MODERATE SWARM OFF NORTHERN CALIFORNIA

 

EARTHQUAKE SUMMARY FOR OCTOBER 17, 2017

 

A series of light earthquakes off the coast of Northern California today culminated late in the day with an M 4.2 event.  NEIC reported this earthquake of M 4.2 off the coast of Northern California was felt with intensity II-III in the area(s) of Eureka, California. The last earthquake of M>=4.2 within about 100 km of these epicenters occurred on March 27, 2017 with M 4.2 but the last of larger size was an M 4.6 and 5.0 on September 25, 2016. A moderately large earthquake of M 5.7 hit about 100 km southeast of today's epicenters on September 22, 2017 and this may be regional aftershock activity from that event. October 18 is a high point in the annual seismicity of California and another moderate earthquake in the region is possible in the next several days. This activity is at 148 degree from the Bouvet Island quake of M 6.7 of October 10 and may have been promoted from that source. Forecast 111363 had expected a moderate quake was possible in this region around October 14.

 

O: 17OCT2017 15:12:35  41.1N  127.5W ML=2.8  EMSC   OFF COAST OF NORTHERN CALIFORNIA

O: 17OCT2017 14:58:52  41.2N  127.0W ML=3.0  EMSC   OFF COAST OF NORTHERN CALIFORNIA

O: 18OCT2017 01:30:10  41.2N  127.2W mb=4.2  EMSC   OFF COAST OF NORTHERN CALIFORNIA

O: 17OCT2017 15:20:18  41.3N  127.0W ML=2.8  EMSC   OFF COAST OF NORTHERN CALIFORNIA

O: 17OCT2017 15:22:13  41.3N  127.2W ML=2.8  EMSC   OFF COAST OF NORTHERN CALIFORNIA

O: 17OCT2017 14:02:31  41.3N  127.2W ML=2.9  EMSC   OFF COAST OF NORTHERN CALIFORNIA

O: 17OCT2017 15:20:18  41.3N  127.0W ml=2.8  ANSS   Crescent City California     

P: 14OCT2017 111363    42.5N  126.8W 3.0-4.6 BBAAA  Off Coast of Oregon        

 

On the opposite side of North America a triplet of light earthquakes of M 2.1-2.4 shook New York, Quebec and New Hampshire. These are not unusual events but three in a day at three different epicenters is unusual. These were not reported felt in their respective epicentral areas. Forecasts 111355 and 111358 expected this activity in mid-October.  This activity is at 120 degrees (node 3) from the Bouvet Island quake of M 6.7 of October 10 and may have been promoted from that source.

 

O: 17OCT2017 21:41:26  43.5N   71.6W ML=2.1  EMSC   NEW HAMPSHIRE                

O: 17OCT2017 21:41:25  43.5N   71.6W ml=1.9  ANSS   Sanbornton New Hampshire

P: 14OCT2017 111355    43.0N   71.0W 2.0-4.1 BAAAA  New England                

 

O: 18OCT2017 00:15:14  43.6N   74.5W MD=2.2  EMSC   NEW YORK                      

P: 17OCT2017 111358    45.7N   75.2W 2.0-4.3 ACAAA  New York State             

 

O: 17OCT2017 02:14:10  46.9N   76.4W ML=2.4  NRCA  64 km NW  of Maniwaki         

P: 17OCT2017 111358    45.7N   75.2W 2.0-4.3 ABAAA  New York State             

 

A series of light earthquakes along the path of Hurricane Ophelia in western Europe and the Atlantic Ocean marked the dissipation of that storm. These

occurred in the Azores, Iceland and France. Four earthquakes of M>=3 in France were unusual. Only one earthquake of M>=3.3 has been recorded in northwestern France to date during 2017 - an M 4.1 on July 1, 2017. Other effects from Ophelia included the fanning of deadly fires in Portugal and Spain. More than 60 deaths have been attributed to the Portugal fires, the worst fire season on record.  The activity in Europe had been expected in this summary as:

 

 

"Hurricane Ophelia continued in the North Atlantic with winds up to 115 kts. It is expected to continue as a hurricane and to track west into the Azores and Europe over the next several days. Seismicity in France, Spain and Portugal will probably increase as Ophelia approaches that region. It is then expected to turn to the north reaching Ireland and Scotland around October 18 where minor seismic

events could be triggered by stresses from this unusual hurricane." (October 15, 2017)

 

Much of this activity is occurring at 100-102 degrees from the Bouvet Island quake of October 10 and may be promoted from that source. Seismic energy from large earthquake concentrates on the surface in this distance range.

 

O: 17OCT2017 19:52:44  40.0N   29.9W ML=3.2  EMSC   AZORES ISLANDS REGION        

O: 17OCT2017 20:01:46  40.1N   29.6W ML=3.0  EMSC   AZORES ISLANDS REGION        

P: 18OCT2017 111359    42.0N   29.0W 4.0-5.6 ABAAA  No. Mid-Atlantic Ridge     

 

O: 17OCT2017 23:50:00  42.3N    9.0E ML=3.0  EMSC   CORSICA, FRANCE              

P: 18OCT2017 111346    43.0N   13.0E 3.0-5.3 AACAA  Italy                      

 

O: 18OCT2017 09:37:48  45.5N    6.3E ML=3.2  EMSC   FRANCE                       

O: 17OCT2017 11:35:12  45.5N    6.3E ML=3.3  EMSC   FRANCE                       

P: 15OCT2017 111347    44.0N    7.0E 3.0-4.9 ABAAA  Italy                      

 

O: 18OCT2017 09:06:08  47.5N    0.3W ML=3.0  EMSC   FRANCE                        

P: 18OCT2017 111343    46.0N    3.0E 3.0-5.3 ABCAA  France                     

 

O: 18OCT2017 06:00:24  66.5N   18.0W ML=3.5  EMSC   ICELAND REGION               

P: 12OCT2017 111406    65.0N   18.0W 3.0-4.4 CBAAA  Iceland area                

 

The strongest earthquakes in the world today again occurred in the Tonga region. These included the only events of M>=5 - an M 5.3 and 5.1. They were not reported felt. Forecasts 111428, 111440 and 111441 had expected this activity in mid-October.

 

Like the activity in France and the Azores, much of this activity is occurring at 100-102 degrees from the Bouvet Island quake of October 10 and may be promoted from that source. Seismic energy from large earthquakes concentrates on the surface in this distance range.

 

O: 17OCT2017 07:00:10  16.4S  173.2W mb=4.7  EMSC   TONGA                        

P: 16OCT2017 111428    16.0S  174.0W 4.0-5.5 AAAAA  Tonga Islands              

 

O: 17OCT2017 09:53:45  20.6S  175.6W mb=5.3  EMSC   TONGA                         

P: 13OCT2017 111440    20.0S  175.0W 4.0-5.5 BAAAA  Tonga Islands              

 

O: 17OCT2017 11:27:59  24.0S  175.5W mb=5.1  EMSC   TONGA REGION                 

P: 14OCT2017 111441    25.0S  179.0W 4.0-5.5 BACAA  Tonga Islands              

 

 

 

A

TONGA/FIJI REGION ACTIVE

 

EARTHQUAKE SUMMARY FOR OCTOBER 16, 2017

 

The strongest earthquakes in the world today occurred in the region of Tonga and Fiji. These events of M 5.5 and 5.3 and 5.1 were lightly felt in the area and may have been felt at Pangai, Ha'apai, Tonga according to data from NEIC. These areas became active as the geomagnetic storm ended today. They are located about 10 degrees south of the geomagnetic equator and may have been promoted by effects related to the geomagnetic storm. One of these, an M 4.9, occurred minutes of local solar noon and was probably promoted by tidal stresses which are high at this hour. An M 6.1 hit the Tonga area on October 8 about 500 km north of today's epicenter. The last of M>=5.5 within about 200 km of today's epicenter occurred on September 26, 2017 with M 6.5 and prior to that on June 27, 2017 with M 5.5  These earthquakes are located at 102 degrees from the Bouvet Island earthquake of M 6.7 on October 10. Seismic energy is concentrated on the surface at this  distance from large earthquakes and can help promote additional seismicity at this distance. Forecast 111188 had expected today's activity in mid-October.

 

O: 16OCT2017 20:03:11  23.8S  175.4W mb=5.1  EMSC   TONGA REGION

O: 16OCT2017 18:36:43  23.9S  175.6W Mw=5.5  EMSC   TONGA REGION

O: 16OCT2017 23:52:18  23.9S  175.9W mb=4.9  EMSC   TONGA REGION

O: 16OCT2017 18:20:00  23.9S  175.9W mb=5.1  EMSC   TONGA REGION

O: 16OCT2017 18:09:23  23.7S  175.4W mb=5.4  EMSC   TONGA REGION                 

P:  9OCT2017 111188    24.0S  178.0W 4.0-5.4 CACAA  Tonga Islands              

 

An M 4.1 earthquake in South-Central Canada near Chesterfield today was teh strongest event located in Canada. This epicenter is north of Minnesota and light earthquakes in the area are not uncommon. Three earthquakes of M>=4.1 have hit the area in the past 25 years - an M 4.2 on March 10, 2012; an M 4.4 on May 8, 2004 and an M 5.4 on December 6, 1997. Forecast 111155 had expected a moderate earthquake in this area within about 200 km of this epicenter was possible around October 10. This epicenter is located at 142 degrees from the Bouvet Island earthquake of October 10 and may have been promoted from that source. Other areas at this distance from Bouvet today included an M 4.0 in Hawaii and light earthquakes in Northern California.

 

O: 15OCT2017 02:09:32  65.4N   91.3W ML=4.1  NRCA  231 km NNW of Chesterfield Inle

P: 10OCT2017 111155    65.0N   86.0W 2.5-4.0 BACAA  Nunavit/Hudson Bay, Canada 

 

The strongest earthquake today in the U.S. or Canada was an M 4.5 in the Bering Sea of Alaska. This is in the epicentral region of the Bouvet Island (M 6.7) quake of October 10 and may have been promoted by energy from that source. The only previous earthquake of moderate magnitude this year was an M 4.3  on June 29, 2017. The last earthquake in the Bering Sea within about 250 km of this epicenter with M>=4.5 was an M 4.5 on March 11, 2012. The last of larger magnitude was an M 4.9 on July 10, 2006. Moderate earthquakes in the area often come in pairs, so another such event may occur in the next several days.

 

O: 16OCT2017 13:54:37  63.2N  172.5W mb=4.5  EMSC   BERING SEA                   

O: 16OCT2017 13:54:38  63.2N  172.5W mb=4.5  ANSS   SSW of Gambell Alaska

 

An earthquake of M 4.0 also occurred in the Lana'i City area of the Hawaiian Islands. This event occurred in the western portion of the state and is the strongest west of 157 West longitude since an M 4.1 on July 8, 2003. Earthquakes in the past two years of M 4.2 and M 4.7 occurred about 150 km northeast of today's epicenter on July 30 and February 17, 2017. This epicenter is located at 144 degrees from the Bouvet Island M 6.7 of October 10, 2017. Forecast 111255 had expected this event was possible around October 12.

 

O: 16OCT2017 17:51:09  19.7N  157.5W ML=4.0  EMSC   HAWAIIAN ISLANDS REGION      

O: 16OCT2017 17:51:09  19.7N  157.5W ml=4.0  ANSS   Lana'i City Hawaii

P: 12OCT2017 111255    19.9N  156.1W 3.0-4.4 BABAA  Hawaii                     

 

RKANSAS SHAKES

 

EARTHQUAKE SUMMARY FOR OCTOBER 15, 2017

 

Global seismicity remained at quiet levels today as the current major geomagnetic storm persisted. There were no earthquakes of M>=5. The largest occurred near the coast of Valparaiso, Chile where it was felt. NEIC reported this earthquake of M 4.9 in Central Chile was felt with intensity IV in La Ligua, Valparaiso and Illapel, Coquimbo and II-III in the area(s) of Valparaiso, Vina del Mar, Quilpue, Quillota, Villa Alemana, Calera, Cabildo and San Antonio, Chile. Forecast 111445 had expected this event around October 17.

 

O: 15OCT2017 10:59:13  32.2S   72.8W mb=4.9  EMSC   OFF COAST OF VALPARAISO, CHILE

P: 17OCT2017 111445    31.0S   70.0W 4.0-5.5 ABBAA  Central Chile              

 

"The geomagnetic field was at minor storm conditions today.  The AP level was 26. High latitude geomagnetic field saw major storm conditions with AP at 49. The geomagnetic storm today is the strongest since September 28 when AP reached 55. This could promote a strong earthquake today but more likely 4-5 days after the geomagnetic storm ends.  These are most likely near the geomagnetic equator and/or at high latitudes." (October 14-15, 2017)

 

The most widely felt earthquake in the U.S. or Canada today occurred as an M 3.7 in Arkansas. NEIC reported it was felt with maximum intensity IV in Arkansas at Dell, Manila, Etowah, Leachville, Keiser, Osceola, Blytheville, Monette, with lesser shaking of II-III in Arkansas at Caraway, Luxora, Lepanto, Wilson, Senath. It was also felt lightly in Missouri at Arbyrd, Cardwell, Steele, and in general within about 50-100 km of the epicenter. Felt reports also were noted from Tennessee, Mississippi, Illinois, Kentucky, Indiana, Louisiana, and Minnesota.  This is the strongest earthquake in Arkansas during 2017. The last earthquake within about 200 km of this epicenter with M>=3.7 occurred on April 4, 2015 with M 4.0 and prior to that on June 4, 2014 (M 3.8). Forecast 111046 had expected a light to moderate earthquake in this area around October 9.

 

O: 15OCT2017 10:16:25  35.8N   90.1W MD=3.7  EMSC   ARKANSAS                     

O: 15OCT2017 10:16:25  35.8N   90.1W md=3.7  ANSS   SE of Manila Arkansas

P:  9OCT2017 111046    36.0N   91.0W 2.0-4.4 CAAAA  New Madrid area            

 

The strongest earthquake in the U.S. or Canada today was an M 4.1 in the Pribilof Islands, Alaska. The only event in this region during the past year was an M 4.5 at this same epicenter of June 14, 2017. This is a remote area and these events were not reported felt. Forecast 111384 had expected regional seismicity around October 12.

 

O: 15OCT2017 06:50:30  56.5N  168.3W ML=4.1  EMSC   PRIBILOF ISLANDS, ALASKA REGIO

P: 12OCT2017 111384    53.7N  167.0W 3.5-5.0 BCAAA  Fox Islands, Aleutians     

 

An unusual earthquake also occurred today as an M 3.4 in the area west of Vernonia in western Oregon.  NEIC reported this earthquake of M 3.4  in Oregon was felt with maximum intensity IV in Oregon at Seaside, Gales Creek, and II-III in the area(s) of Vernonia, Astoria, Nehalem, North Plains, Rockaway Beach, Portland and Halsey, Oregon.  The last earthquake within about 100 km of this epicenter with M>=3.4 occurred as an M 3.6 on November 16, 2016. The only other such event in the past 25 years in this region was an M 3.7 ten years ago on September 24, 2007. This, as well as quakes in northern California, Hawaii, Idaho and central California lie at 143-148 degrees from the Bouvet quake of October 10, a distance where concentrated seismic energy returns to the surface and may help promote further seismicity. A reader (PB) sent the following first-hand account of this earthquake:

 

“Last night there was a quake listed by USGS as WNW of Vernonia, OR. It was actually centered in Jewell, a small rural area in the Northwest Oregon Coast Range. I live about 5-7 miles from the epicenter and even though it was only a 3.4 it woke me from a sound sleep and shook my house like crazy. Pictures on the walls tilted and a few small items fell over. I had gone to bed early and made sure I did all I could to ensure a good night's sleep (massage chair, chamomile tea, warm room etc) since I was supposed to be up very early for work. Because I was sleeping so deeply I don't know how long it was shaking before it woke me. Of course I coulnd't go back to sleep, heart pounding so hard it was scary. So did some research online for area quakes and found one reference to local faults on our county website.” (PB October 15, 2017)

 

O: 16OCT2017 05:28:09  45.9N  123.5W ML=3.4  EMSC   OREGON                        

O: 16OCT2017 05:28:09  45.9N  123.5W ml=3.4  ANSS   WNW of Vernonia Oregon

P: 16OCT2017 111374    46.9N  122.0W 2.0-4.1 AAAAA  Washington state, U.S.     

 

An unusual earthquake of M 3.5 occurred in northwestern France today. EMSC reported this earthquake was felt lightly in France at Bouffere and Saint-Clementin. This may be related to stresses from Hurricane Ophelia which remnants passed to the west of this epicenter today. This activity had been expected in the previous issue of this summary as:

 

 

"Hurricane Ophelia continued in the North Atlantic with winds up to 115 kts. It is expected to continue as a hurricane and to track west into the Azores and Europe over the next several days. Seismicity in France, Spain and Portugal will probably increase as Ophelia approaches that region." (October 15, 2017)

 

Forecast 111372 had expected this event to the southeast of this epicenter around October 12. The last earthquake in the area within about 100 km of this epicenter with M>=3.5 was an M 2.9 on January 4, 2017.

 

O: 15OCT2017 22:44:48  47.0N    2.3W ML=3.5  EMSC   FRANCE                       

P: 12OCT2017 111372    46.0N    1.0W 3.0-5.3 BAAAA  Spain                      

 

SHAKING OCCURS IN MONTANA; VENEZUELA; JAVA

 

EARTHQUAKE SUMMARY FOR OCTOBER 14, 2017

 

It was another relatively quiet day in global seismicity with no events of M>5.1. This may be related to the current strong geomagnetic storm which has been in progress for the past four days. These storms disrupt the ionospheric ring currents and induced telluric currents which promote seismicity. Several unusual events did occur today however - the strongest aftershock in western Montana in three months (M 3.9-4.0) and an M 5.1 in western Venezuela near the Colombia border. This was accompanied by a near-antipodal series of events south of Java, Indonesia. Both the Venezuela and the Java epicenters were located at 90 degrees (node 4) from the last strong global earthquake - the M 6.7 in the Bouvet Island area of October 10 - and were probably promoted from that source.

An M 4.5 in Iran and a M 4.5 in Crete were also at 90 degrees from Bouvet Island today.

 

Several light earthquakes were felt today in western Montana. The largest of these was an M 3.9 but associated shocks of M 3.4 were also felt in Lincoln and Helena, Montana with intensity II. The M 3.9 was reported felt with maximum intensity IV in Canyon Creek, Montana, 20 km from the epicenter. Intensity II-III was also reported from Montana at Lincoln, Helena, Clancy, Deer Lodge, Great Falls, and within about 100 km of the epicenter. This is the strongest aftershock of the M 5.8 event of July 6, 2017 in western Montana since the immediate aftershocks on that date which reached M 4.9. An M 3.9-4.0 occurred on July 17 as well.  Forecast 111376 had expected the aftershocks region to be active around October 12. Western Montana is located at 143 degrees from the  M 6.7 in Bouvet Island of October 10. This is a distance at which triggering is likely from core reflections and refractions of seismic energy which returns to the surface at this distance from large earthquakes. Other areas at this distance from Bouvet Islands include Central and northern California where a similar M 3.9 occurred yesterday.

 

O: 15OCT2017 01:41:51  46.9N  112.5W ML=3.9  EMSC   WESTERN MONTANA              

O: 15OCT2017 02:24:49  46.9N  112.6W ML=3.4  EMSC   WESTERN MONTANA              

P: 12OCT2017 111376    46.4N  111.4W 2.0-4.2 BAAAA  Yellowstone/Wyoming        

 

An unusual earthquake occurred today in western Venezuela with M 4.9-5.1. NEIC reported maximum intensity IV in Floridablanca, Santander, Colombia with other lighter shaking of II-III in this area at Pamplona, Piedecuesta, Bucaramaga, and in Sogamoso, Boyaca, Colombia. It was also felt in Venezuela at La Fira and in Rubio, Tachira, Venezuela. The last earthquake within about 100 km of this epicenter in Venezuela was an M 5.1 on August 8, 2017. The last of larger magnitude in the area was an M 5.7 on February 17, 2014 and M 5.2 on July 16, 2007.  Forecast 111216 had expected today's earthquake in this area was likely around October 12.

 

O: 14OCT2017 08:35:43   7.3N   71.9W Mw=4.9  EMSC   APURE, VENEZUELA             

P: 12OCT2017 111216     7.0N   73.0W 4.0-5.7 AAAAA  Colombia                   

 

A series of three moderate events of M 4.6, 4.9 and 4.9 also occurred south of Java, Indonesia today. These occurred in the antipodal area of the Venezuela earthquake. The last earthquake within about 150 km of this epicenter with M>=4.9 occurred August 27, 2017 with M 5.5 and prior to that on November 7, 2015 with M 5.3. Forecast 111427 had expected this activity around October 15.

 

O: 14OCT2017 14:03:31  10.8S  112.3E mb=4.9  EMSC   SOUTH OF JAVA, INDONESIA     

O: 14OCT2017 06:06:56  10.9S  112.3E ML=4.9  EMSC   SOUTH OF JAVA, INDONESIA     

O: 14OCT2017 05:35:36  10.9S  112.3E mb=4.6  EMSC   SOUTH OF JAVA, INDONESIA     

P: 15OCT2017 111427    10.0S  109.0E 4.0-5.5 AACAA  So. of Java                 

 

MODERATELY STRONG AFTERSHOCK IN OAXACA, MEXICO

 

EARTHQUAKE SUMMARY FOR OCTOBER 13, 2017

 

The strongest earthquake in the world today was an M 5.4 aftershock in the Chiapas/Oaxaca region of eastern Mexico. NEIC reported it was felt with intensity II-III in Oaxaca at Tehuantepec, Xadani, Mitla, Santa Lucia del Camino, Puerto Escondido, Putla, and Oaxaca in Chiapas at Tuxtla Gutierrez, San Cristobal de las Casas, in Mexico at Zacamulpa, Mexico City, Nezahualcoyotl; in Quezaltenango, Guatemala; in Tabasco, Mexico at Cardenas, Villahermosa, and at Coatzacoalcos, Veracruz, Mexico. This is the strongest aftershock in the Chiapas/Oaxaca area in more than two weeks. The last larger aftershock was an M 5.6 on September 29. Forecast 111250 and 111248 had expected this activity at this time.

 

O: 13OCT2017 20:12:27  15.1N   93.8W ML=4.0  UNAM  l SUROESTE de PIJIJIAPAN, CHIS *:

O: 13OCT2017 07:51:17  14.8N   94.1W ML=4.2  UNAM  al SUROESTE de PIJIJIAPAN, CHIS *:

O: 13OCT2017 06:38:22  15.0N   94.1W ML=4.3  UNAM  al SUROESTE de PIJIJIAPAN, CHIS *:

O: 13OCT2017 07:41:52  15.0N   94.4W ML=4.0  UNAM  al SUROESTE de TONALA, CHIS *: 15.

O: 13OCT2017 09:37:22  15.1N   94.4W ML=4.0  UNAM  al SUROESTE de TONALA, CHIS *: 15.

O: 13OCT2017 09:39:34  15.1N   94.5W ML=4.0  UNAM  al SUROESTE de TONALA, CHIS *: 15.

O: 13OCT2017 17:11:11  15.0N   94.5W ML=4.1  UNAM  al SUROESTE de TONALA, CHIS *: 15.

O: 13OCT2017 23:40:33  14.8N   94.5W ML=4.4  UNAM  al SUROESTE de TONALA, CHIS *: 14.

O: 13OCT2017 08:46:52  15.3N   94.7W ML=4.1  UNAM  al SURESTE de SALINA CRUZ, OAX *:

O: 13OCT2017 08:17:03  15.3N   94.8W ML=4.0  UNAM  l SURESTE de SALINA CRUZ, OAX *: 1

O: 13OCT2017 09:15:47  15.4N   94.8W ML=4.1  UNAM  l SURESTE de SALINA CRUZ, OAX *: 1

O: 13OCT2017 11:23:29  15.5N   94.9W ML=4.8  UNAM  l SURESTE de SALINA CRUZ, OAX *: 1

O: 13OCT2017 13:48:45  16.4N   95.0W ML=4.0  UNAM   NORESTE de JUCHITAN DE ZARAGOZA,

O: 14OCT2017 01:01:54  16.4N   95.0W ML=4.1  UNAM   ESTE de JUCHITAN DE ZARAGOZA, OAX

O: 13OCT2017 05:48:15  16.4N   95.1W ML=4.3  UNAM   SUROESTE de JUCHITAN DE ZARAGOZA,

O: 13OCT2017 20:12:27  15.1N   93.8W ML=4.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 13OCT2017 09:37:22  15.1N   94.4W ML=4.0  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 13OCT2017 09:39:34  15.1N   94.5W ML=4.0  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 13OCT2017 17:11:11  15.1N   94.5W ML=4.1  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 13OCT2017 23:40:39  15.5N   94.2W mb=4.6  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 13OCT2017 11:23:32  15.9N   94.7W mb=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 14OCT2017 01:01:54  16.4N   95.0W ML=4.1  EMSC   OAXACA, MEXICO

O: 13OCT2017 13:48:45  16.5N   95.0W ML=4.0  EMSC   OAXACA, MEXICO

O: 14OCT2017 00:20:59  16.4N   94.7W Mw=5.4  EMSC   OAXACA, MEXICO               

P: 12OCT2017 111250    16.0N   94.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

P: 13OCT2017 111248    14.0N   93.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

P: 14OCT2017 111248    15.0N   93.0W 3.5-5.6 AAAAA  Chiapas, Mexico            

 

The strongest earthquake widely felt in the U.S. or Canada today was an M 3.9-4.0 in Northern California in the midst of the most deadly fires that state has ever seen. NEIC reported this earthquake was felt with maximum intensity IV in Ukiah, California and II-III in Potter Valley, Willits, Upper Lake, Comptche, Philo, Lakeport, Nice, Hopland, Fort Bragg, Clearlake Oaks, Kelseyville, Covelo, Clearlake, Rohnert Park, Bridgeville, Forest Ranch, Concord, California.

The last earthquake of M>=3.9 in the Lake Country north of 39N and west of 123W in California was an M 4.1 on November 6, 2016 and prior to that on October 4, 2014 (M 3.9). Forecast 111034 and 111297 had expected this activity was likely between October 4 and 16.

 

O: 13OCT2017 23:10:32  39.3N  123.2W Mw=3.9  EMSC   NORTHERN CALIFORNIA          

P:  4OCT2017 111034    39.4N  123.3W 2.5-4.5 CAAAA  Central California         

P: 16OCT2017 111297    39.8N  123.5W 2.5-4.4 BAAAA  Central California         

 

The largest earthquake in the vicinity of the U.S. outside Alaska was an M 4.5 off the coast of Oregon. NEIC reported it was possibly felt in Bandon, Oregon. This is a seismic area which has been relative quiet in recent months. No events of M>=4.4 within about 200 km of this epicenter have occurred during 2017. Earthquakes of M 4.3 hit the area within about 50 km of this epicenter on August 27 and September 5. Forecast 111108 had expected this event was likely around October 11.

 

O: 13OCT2017 16:55:21  43.8N  127.2W mb=4.4  EMSC   OFF COAST OF OREGON          

P: 11OCT2017 111108    43.9N  128.4W 3.0-4.5 AAAAA  Off Coast of Oregon        

 

The strongest earthquakes in the U.S. today again occurred in the Fox Islands region of Alaska. This is the third day of this sequence near the antipode of

 the M 6.7 in Bouvet Island, South Atlantic. The largest of today's events was an M 4.7 that occurred within minutes of local solar noon. Tidal stresses maximize at this time and are likely to have helped promote the earthquake at this time.

 

The last earthquake of M>=4.8 within about 150 km of this Fox Islands epicenter occurred as an M 4.9 on September 29, 2017 and prior to that as an M 5.3 on August 9, 2017.  Forecast 111380 had expected today's events within about 50 km of the epicenter were likely around October 16.

 

O: 13OCT2017 08:00:48  52.0N  170.1W mb=4.8  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O: 13OCT2017 22:54:50  52.4N  169.5W ML=3.6  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O: 13OCT2017 23:31:50  52.4N  169.8W mb=4.7  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

P: 16OCT2017 111380    52.4N  170.7W 3.5-5.0 BAAAA  Andreanoff Isls, Aleutians 

 

A light earthquake of M 3.0 was widely felt with intensity II-III south of San Francisco, California today. NEIC reported it was felt in Central California at Gilroy, Watsonville, Aromas, San Martin, San Juan Bautista, Aptos, Morgan Hill, Moss Landing, Capitola, Santa Cruz, Los Gatos, Felton, San Jose, San Francisco, and Auburn, California. NEIC reported an aftershock of M 2.5 in Central California was felt with intensity II-III in the area(s) of Gilroy, San Juan Bautista, Morgan Hill, Aptos and Sunnyvale, California.  Forecasts 111029 and 111294 had expected this activity was likely around October 11-14. Seismicity in California often increases at this time of yea, with maximum output around October 15-20, the second highest peak after that half a year earlier in mid-April. This is probably promoted by regional fires (which are an unloading event) and tropical cyclones which change motion of the North American plate.

 

 

O: 13OCT2017 11:32:28  37.0N  121.5W MD=2.5  EMSC   NORTHERN CALIFORNIA          

O: 13OCT2017 18:12:55  37.0N  121.7W MD=2.0  EMSC   NORTHERN CALIFORNIA          

O: 13OCT2017 11:13:53  37.0N  121.7W ML=2.9  EMSC   NORTHERN CALIFORNIA          

P: 11OCT2017 111029    37.2N  122.1W 2.5-4.4 AAAAA  Central California         

P: 14OCT2017 111293    37.1N  121.1W 2.5-4.4 AAAAA  Central California         

 

ANDREANOF ISLANDS ACTIVE

 

EARTHQUAKE SUMMARY FOR OCTOBER 12, 2017

 

The strongest seismicity in the U.S. or Canada today occurred in the Andreanof Islands of Alaska. This activity of M 4.8, 4.8 and 4.2 is occurring in the eastern Andreanof Islands within about 200 km of the exact antipode of the  Bouvet Island M 6.7 of October 10. This had been expected in previous issues of this summary as:

 

"The exact antipode (of the Bouvet Island earthquake) is in the Andreanof Islands, neighboring the Rat Islands on the east at 54N 172W. This is a seismic area and could see a moderate to large quake in the next several days, although this seems unlikely at this time." (October 10-11, 2017)

 

The Bouvet Island earthquake occurred at 54S 9E while today's activity in the Fox Islands occurred at 52-53N 170-171W within at minimum 100 km from the exact Bouvet antipode. Frequent readers of this report know that two epicenters are antipodal if the latitudes are numerically the same and in opposite hemispheres and the longitudes add to 180 and are in opposite hemispheres. In this case consider 54S and 53N latitudes and 9E and 171W. Further activity in the Fox or Andreanof Islands is likely in the next several days.

 

The last earthquake of M>=4.8 within about 150 km of this Fox Islands epicenter occurred as an M 4.9 on September 29, 2017 and prior to that as an M 5.3 on August 9, 2017.  Forecast 111380 had expected today's events within about 50 km of the epicenter were likely around October 16.

 

O: 13OCT2017 08:00:48  52.0N  170.1W mb=4.8  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O: 13OCT2017 07:39:27  52.9N  170.5W mb=4.3  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O: 12OCT2017 08:23:03  52.1N  170.1W mb=4.8  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O: 12OCT2017 08:23:03  52.1N  170.2W mb=4.8  ANSS   Yunaska Island Alaska

P: 16OCT2017 111380    52.4N  170.7W 3.5-5.0 AAAAA  Andreanoff Isls, Aleutians 

 

O: 11OCT2017 00:08:26  54.2S    8.1E mb=5.3  EMSC   BOUVET ISLAND REGION         

O: 10OCT2017 18:53:33  54.3S    8.5E Mw=6.7  EMSC   BOUVET ISLAND REGION         

P: 12OCT2017 111456    55.0S    2.0E 4.0-5.4 AACAA  Atlantic-Indian Ridge      

 

The largest earthquake in the world today was an M 5.5 in Argentina. No damage was reported from this intermediate depth event. NEIC reported this earthquake of M 5.5 in Argentina was felt with maximum intensity IV in Los Andes, Valparaiso, Chile, and II-III in the area(s) of Valparaiso, and Santiago, Chile and in Argentina at Rio Tercero, Cordoba; San Juan and  Mendoza. This is the strongest earthquake in Argentina within about 200 km of this epicenter since an M 5.6 on September 9, 2016. The only event of significantly larger magnitude in this region in the past 25 years was an M 5.8 on November 13, 2015. The only other event in the region of M>=5.5 in the past 25 years was an M 5.5 on March 17, 2004.  Forecast 111445 had expected an earthquake in this area around October 19.

 

O: 12OCT2017 18:59:09  31.0S   65.6W Mw=5.5  EMSC   CORDOBA, ARGENTINA           

P: 19OCT2017 111445    31.0S   68.0W 4.0-5.6 CABAA  Central Chile              

 

A moderate earthquake of M 4.1-4.4 in northern Philippines occurred today as the eye of Tropical Storm Khanun passed over this epicenter. This is another example of seismic triggering by stresses associated with tropical cyclones. This had been expected in the previous issue of this summary:

 

"Tropical Storm Khanun (24W) continued over the northern Philippines today with winds up to 45 kts. It is expected to track to the west reaching North Vietnam near Hanoi by October 16. Seismicity in northern Philippines may increase as this storm passes through the area. Strike-slip events in southeastern Asia may also be promoted in the next week." (October 11-12, 2017)

 

PHIVOLCS reported this earthquake was felt with intensity III in Tuguegarao City, Northern Philippines. The last earthquake with M>=4.4 within about 100 km of this epicenter in Luzon, Philippines was an M 4.7 on July 7, 2017.  Forecast 110985 had expected a moderate quake in Luzon, Philippines around October 10.

 

O: 12OCT2017 05:36:13  17.2N  122.0E mb=4.4  EMSC   LUZON, PHILIPPINES           

O: 12OCT2017 05:36:13  17.4N  121.9E MS=4.1  PHI  Felt with intensity III in Tugue

P: 10OCT2017 110985    19.0N  120.0E 3.5-4.9 ABBAA  Luzon, Philippines         

 

MODERATE QUAKES IN GREECE, SOUTH SANDWICH ISLANDS

 

EARTHQUAKE SUMMARY FOR OCTOBER 11, 2017

 

The strongest earthquake in the world today was an M 5.3 in the South Sandwich Islands. It was not reported felt in this remote area. An earthquake series beginning with an M 6.5 hit the area about 100 km west of this epicenter beginning on May 10, 2017 with the last M 5.3 on May 15, 2017. This is the first such earthquake in the area east of 25W in the South Sandwich Islands since an M 5.6 on December 29, 2014.  Forecast 111209 had expected a moderate earthquake in this area was likely around October 9. This earthquake occurred within about an hour of local solar midnight and may have been promoted by elevated tidal stresses which are high at this hour.

 

O: 12OCT2017 03:12:23  56.3S   24.7W mb=5.3  EMSC   SOUTH SANDWICH ISLANDS REGION

P:  9OCT2017 111209    56.0S   26.0W 4.0-6.0 BAAAA  So. Sandwich Islands       

 

An earthquake of M 5.1 occurred today in the region of Greece. NEIC reported it was felt with maximum intensity IV in Volos, Magnesia, Greece as well as in Attiki at Peuki, Pallini, Kholargos, Viron, Voula, Vouliagmeni, and in Rentina, Karditsa, Greece. Lesser shaking occurred within about 200 km of the epicenter in areas of Thessaloniki, Ahaia, Evvoia nad Magnisia. Communities within 125 km of this quake feeling the shaking included Patitirion, Magnisia; Skiros, Evvoia and Kifisia, Attiki, Greece. The last earthquake in the Aegean Sea with M>=5.1 within about 200 km of this epicenter occurred as an M  5.2 on June 9, 2015. The last of significantly larger size was an M 5.4 on November 17, 2014. Forecast 111286 expected this event within about 100 km of this epicenter was likely around October 15. This earthquake occurred within about an hour of local solar midnight and may have been promoted by elevated tidal stresses which are high at this hour.

 

O: 11OCT2017 22:49:43  39.1N   24.2E Mw=5.1  EMSC   AEGEAN SEA                   

P: 15OCT2017 111286    39.0N   23.0E 3.0-4.8 BAAAA  Aegean Sea                 

 

The strongest earthquake in the U.S. or Canada today was an M 4.9 in the area south of Alaska near the Alaska Peninsula. The last earthquake of M>=4.9 in the

area south of Alaska within about 150 km since an M 5.5 on December 7, 2013. Forecast 111377 had expected this event was likely around October 12.

 

O: 12OCT2017 00:01:53  54.9N  156.1W mb=4.9  EMSC   SOUTH OF ALASKA              

P: 12OCT2017 111377    54.8N  158.7W 3.5-5.1 AABAA  Alaska Peninsula           

 

An unusual earthquake occurred today in the area of Vancouver Island with M 4.5.

NEIC reported this earthquake of M 4.5 in Vancouver, British Columbia, Canada was felt with intensity II-III in the area(s) of British Columbia at Port Alberni, Campbell River, Ladysmith, Sooke, Chemainus, Victoria, White Rock, Cultus Lake and in Washington at Deming, Lynden, Bellingham and Point Roberts.

Earthquakes Canada reported no damage from this event. No tsunami was expected.

This event was preceded by a series of foreshocks of M 3.0 and 3.1. This epicenter is located at 150 degrees from Bouvet Island and may have been promoted by energy from that source. It occurred near local solar midnight, a time of  high tidal stresses which may also have helped trigger this event at this time. The last earthquake of M>=4.5 within about 100 km of this epicenter was an  M 4.5 on January 19, 2016. The last of M>4.5 was an M 5.5 on August 19, 2012 more than five years ago. Forecast 111373 had expected this event within about 50 km of this epicenter was likely around October 13.

 

O: 11OCT2017 16:12:04  48.8N  129.0W ML=3.0  NRCA  229 km W   of Tofino

O: 11OCT2017 09:53:24  48.2N  128.3W ML=3.2  NRCA  206 km WSW of Tofino

O: 11OCT2017 09:26:05  48.2N  128.3W ML=4.4  NRCA  205 km WSW of Tofino

O: 11OCT2017 09:26:08  48.4N  127.9W Mw=4.5  EMSC   VANCOUVER ISLAND, CANADA REGIO

P: 13OCT2017 111373    48.3N  128.5W 2.8-4.9 AAAAA  Vancouver Island area      

 

STRONG EARTHQUAKE IN SOUTH ATLANTIC REGION - PROMOTES VANCOUVER AND IDAHO EVENTS

 

EARTHQUAKE SUMMARY FOR OCTOBER 10, 2017

 

A strong M 6.7 earthquake hit the Bouvet Island region of the South Atlantic today. It was followed by a moderate aftershock of M 5.3. These events are the strongest in the region in the year 2017. The only moderate event in the area this year was an M 5.1 on March 31, 2017. The only event in the Bouvet Islands region in the past 25 years of M>=6.7 had been an M 6.0 on April 15, 2014 about 100 km north of today's epicenter. This Bouvet Island earthquake is in the antipodal zone from the last large global earthquake - the M 6.6 in the Rat Islands of October 8. It is likely it was triggered by strong, concentrated, seismic energy from that event. The exact antipode is in the Andreanof Islands, neighboring the Rat Islands on the east at 54N 172W. This is a seismic area and could see a moderate to large quake in the next several days, although this seems unlikely at this time. EMSC reported today's earthquake was felt strongly in the Bouvet Island region. It was followed in the distance range 140-150 degrees by unusually strong earthquakes of M 4.5-4.6 in southern Idaho and Vancouver, British Columbia, Canada. Forecast 111456 had expected a moderate to strong quake in this area around October 12. This epicenter is located at 109 degrees from the great Chiapas, Mexico earthquake of September 8 (M 8.2) and may have been promoted from that source as well. Activity at this distance from Bouvet Island today (100-109 degrees) occurred also in Banda Sea, Caspian Sea, Chiapas, and the north Atlantic west of Portugal.

 

O: 11OCT2017 00:08:26  54.2S    8.1E mb=5.3  EMSC   BOUVET ISLAND REGION         

O: 10OCT2017 18:53:33  54.3S    8.5E Mw=6.7  EMSC   BOUVET ISLAND REGION         

P: 12OCT2017 111456    55.0S    2.0E 4.0-5.4 AACAA  Atlantic-Indian Ridge      

 

The largest earthquake in the U.S. or Canada today was an M 4.5 in the Vancouver Island area of British Columbia, Canada. NEIC reported it was felt with intensity II-III in Victoria, B.C. and in Cultus Lake, British Columbia, Canada. This event was preceded by a series of foreshocks of M 3.0 and 3.1. This epicenter is located at 150 degrees from Bouvet Island and may have been promoted by energy from that source. It occurred near local solar midnight, a time of  high tidal stresses which may also have helped trigger this event at this time. The last earthquake of M>=4.5 within about 100 km of this epicenter was an  M 4.5 on January 19, 2016. The last of M>4.5 was an M 5.5 on August 19, 2012 more than five years ago. Forecast 111373 had expected this event within about 50 km of this epicenter was likely around October 13.

 

O: 11OCT2017 09:26:08  48.4N  127.9W Mw=4.5  EMSC   VANCOUVER ISLAND, CANADA REGIO

O: 11OCT2017 09:26:08  48.4N  127.9W mb=4.5  ANSS   WSW of Tofino Canada

P:  3OCT2017 111118    48.7N  129.0W 2.8-4.9 CAAAA  Vancouver Island area      

P: 13OCT2017 111373    48.3N  128.5W 2.8-4.9 AAAAA  Vancouver Island area      

 

O: 10OCT2017 08:29:56  49.0N  129.2W ML=3.0  NRCA  228 km SW  of Pt. Hardy       

O:  9OCT2017 12:01:00  49.0N  129.3W ML=3.1  NRCA  236 km SW  of Pt. Hardy       

O:  9OCT2017 12:13:45  48.9N  129.2W ML=3.1  NRCA  234 km SW  of Pt. Hardy       

P: 13OCT2017 111373    48.3N  128.5W 2.8-4.9 AAAAA  Vancouver Island area      

 

An M 4.5-4.6 earthquake also occurred in the aftershock zone of southern Idaho. NEIC reported this event in southern Idaho of M 4.1 was felt with maximum intensity IV in Idaho at Montpelier and at Idaho Falls and in Wyoming at Afton, Auburn. Lesser shaking of intensity II-III was felt in Wyoming at Bedford, Thayne, Rock Springs, Green River, Jackson, Grover and in Utah at Portage. It was also felt with intensity II-III in Idaho at Grace, Paris, Preston, Saint Charles, Lava Hot Springs, Dayton, Pocatello and Malad City.  NEIC reported an aftershock of M 2.8 in southern Idaho was felt with intensity IV in the area(s) of Soda Springs, Idaho. This is the strongest aftershock of the M 5.3 of September 2 since an M 4.6 on September 11 a month ago. It may have been promoted by the Bouvet Island earthquake which is located at 140-141 degrees away. Seismic energy from the core boundaries is reflected and refracted and returns to the surface in this distance range in a concentrated form. Seismicity in this distance range often increases following strong quakes suggesting some of this is triggered. Forecast 111375 expected this earthquake within the aftershock zone was likely around October 12.

 

O: 11OCT2017 01:53:54  42.6N  111.4W ML=2.8  EMSC   SOUTHERN IDAHO               

O: 10OCT2017 10:40:33  42.6N  111.4W Ml=2.1  EMSC   SOUTHERN IDAHO               

O: 11OCT2017 01:24:25  42.6N  111.4W mb=4.6  EMSC   SOUTHERN IDAHO               

O: 11OCT2017 01:24:25  42.5N  111.4W mw=4.1  ANSS   Soda Springs Idaho

O: 10OCT2017 10:04:00  42.7N  111.4W ML=2.2  EMSC   SOUTHERN IDAHO               

P: 12OCT2017 111375    43.0N  111.5W 2.0-4.1 AAAAA  Yellowstone/Wyoming        

 

STRONGLY FELT QUAKES IN CENTRAL CALIFORNIA AND TARAPACA, CHILE

 

EARTHQUAKE SUMMARY FOR OCTOBER 9, 2017

 

A strong earthquake of M 6.3 hit the Tarapaca region of northern Chile today. CSN reported this earthquake was felt with intensity   VII in  Arica, Pocon Chile, VI Cuya, Putre,   V  Visviri, Alcerreca, Quebrada Blanca, Pozo Almonte, Mamina, La Tirana, Pisagua, Huara, Alcerreca, IV Alto Hospicio, Quillagua, Ujina, Pica, Colchane, Cerro Colorado, Cancosa, III Chungara-Complejo Fronterizo, Chile. Felt in Tarapaca, Arica, Parinacota and Antofagasta, Chile and in northern Peru.

NEIC reported it was felt with intensity V in Tarapaca at Arica, Chile and in Tacna, Peru. Intensity IV was reported from Iquique, Arequipa and Ilo, Moquegua, Peru with lesser shaking at La Paz, Bolivia. Previous issues of this summary had pinpointed the likelihood of a strong quake in Tarapaca at this time as:

 

"The induced motions (from Hurricane Irma) can affect regional seismicity but much of this motion will be absorbed by the geologic plasticity of the Florida Peninsula. Some effect on seismicity along the western North American subduction zone as noted above can be expected. But areas along the northern South American subduction zone are also likely to be affected. For example, during the landfall event of October 20, 1921, an earthquake of M 7.1 hit southern Peru and northern Chile in the Tarapaca area (also on October 20). In that hurricane no major effects were noted in the Mexican or California regions to seismicity. In general, with the exception of the northern South American subduction zone there is little evidence that landfall in the Tampa area of Florida is highly promotional to regional seismicity patterns." (September 9, 2017)

 

The epicenter in Tarapaca, Chile is about 10 degrees south of the local geomagnetic equator and was likely promoted by telluric currents induced from ionospheric ring currents overhead. This is the strongest earthquake within about 200 km

of this event in Tarapaca since an M 6.4 on March 23, 2015. Forecast 111186 had expected this event was likely about 100 km to the south of today's epicenter around October 8. This epicenter is at the third node (120 degrees) from the Rat Island event yesterday of M 6.6 and was probably promoted from that source.

 

O: 10OCT2017 06:32:19  18.6S   69.6W Mw=6.3  EMSC   TARAPACA, CHILE              

O: 10OCT2017 07:21:42  18.6S   69.7W Mw=4.8  EMSC   TARAPACA, CHILE              

O: 10OCT2017 07:04:45  18.6S   69.8W Mw=4.5  EMSC   TARAPACA, CHILE              

O: 10OCT2017 06:32     18.5S   69.7W mb=6.3  GUC    Arica, Pocon Chile, VI Cuya, P

P:  8OCT2017 111186    20.0S   70.0W 4.0-5.7 ABAAA  So. Peru/Bolivia           

 

The strongest earthquake in the U.S. or Canada today was an M 4.1 in the Aromas area south of San Francisco, California.

It was widely felt in the region. NEIC reported intensity IV in San Jose, 10 km from the epicenter and V in Coyote, California. Intensity II-III was also felt at Mount Hamilton, Morgan Hill, Milpitas, Livermore, Campbell, Los Gatos, Santa Clara, San Martin and in general within about 100 km of the epicenter. This is the first earthquake of M>=4 in the San Francisco area since an M 4.0  on August 17, 2015. The last earthquake in this region of larger magnitude was an M 4.3 on March 30, 2009. The only event in the area of larger magnitude than this in the past 10 years occurred 10 years ago as an M 5.5 on Halloween October 31, 2007. As noted in the previous summary this area was subject to triggering from the M 6.6 in the Rat Islands, Alaska yesterday. It lies at 45 degrees (node 8) from that event, the strongest in the U.S. in more than two years as noted:

 

 

"An earthquake of M 2.9 south of San Francisco today was followed by an M 2.5 about eight hours later. This activity had been expected in forecast 111029 to occur in early October. NEIC reported this earthquake of M 2.5 in Central California was felt with intensity II-III in the area(s) of San Juan Bautista and Morgan Hill, California. This activity is at 45 degrees from the Rat Islands event and may represent an area where a larger earthquake could occur in the next several days." (October 8-9, 2017)

 

Forecast 111029 had expected this event within this area was likely up to M 4.4 around October 11.

 

O: 10OCT2017 00:53:18  37.3N  121.7W Mw=4.1  EMSC   NORTHERN CALIFORNIA          

P: 11OCT2017 111029    37.2N  122.1W 2.5-4.4 AAAAA  Central California         

 

STRONG SEISMICITY AT HIGH LATITUDES; NEAR GEOMAGNETIC EQUATOR

 

EARTHQUAKE SUMMARY FOR OCTOBER 8, 2017

 

Strong earthquakes hit three areas today. Two of these were at high auroral latitudes - an M 6.6 in the Rat Islands and an M 6.3 in the Balleny Islands south of New Zealand. The third occurred about 10 degrees south of the geomagnetic equator in Tonga with M 6.1. The Rat Islands earthquake was the strongest in the U.S. or Canada in nearly two years. This was the seismic pattern expected for this time as noted in previous issues of this summary:

 

"The strongest associated seismicity is likely around October 5-8 with a strong earthquake about 10-15 degrees from the geomagnetic equator or at auroral latitudes is possible during this time period." (October 3-6, 2017)

 

The earthquake in the Rat Islands of M 6.6 was the strongest in the U.S. or Canada since an M 7.1 on January 24, 2016 near Anchorage, Alaska. An M 7.7 quake hit west of today's epicenter  in the Komandorsky Islands, Russia on July 17, 2017 and was preceded a month-and-a-half earlier by an M 6.8 west of the Near Islands, Alaska. Today's earthquake of M 6.6 appears to be the strongest aftershock to date of the M 7.9 which hit the Rat Islands on June 23, 2014.

 

Forecast 111139 had anticipated a possibly strong earthquake in the Rat Islands within about 100 km of this epicenter was likely around October 4. This epicenter is at the fifth node from the strong earthquakes in Mexico (72 degrees) and was probably promoted from those sources.

 

O:  8OCT2017 22:34:33  52.4N  176.8E Mw=6.6  EMSC   RAT ISLANDS, ALEUTIAN ISLANDS

P:  4OCT2017 111139    51.0N  178.0E 4.0-5.8 BBAAA  Rat Islands                

 

At the time of the M 7.9 Rat Islands earthquake in June, 2014, a strong sequence of light to moderate earthquakes followed the next day in Central California. At the time this summary noted the connection between these events as follows:

 

"A strong series of light earthquakes is occurring in the Kettleman City area of California to the east of Parkfield. This sequence began with an M 3.2 and an M 3.0 but was followed by at least six light earthquakes of M 2.5-3.0 in the next several hours. These earthquakes are being felt with intensity III in the epicentral area and could represent a foreshock series to a larger regional earthquake. The sequence was probably triggered by seismic energy from the Rat Islands as this epicenter is located at 45 degrees (node 8) from that  great quake" (June 24, 2014)

 

An earthquake of M 2.9 south of San Francisco today was followed by an M 2.5 about eight hours later. This activity had been expected in forecast 111029 to occur in early October. NEIC reported this earthquake of M 2.5 in Central California was felt with intensity II-III in the area(s) of San Juan Bautista and Morgan Hill, California.  This activity is at 45 degrees from the Rat Islands event and may represent an area where a larger earthquake could occur in the next several days.

 

O:  8OCT2017 10:11:21  36.5N  121.0W MD=2.5  EMSC   CENTRAL CALIFORNIA           

O:  8OCT2017 01:40:15  36.9N  121.6W MD=2.9  EMSC   CENTRAL CALIFORNIA           

P:  6OCT2017 111029    36.7N  121.4W 2.5-4.4 AAAAA  Central California         

 

 

An M 6.2 (EMSC) - M 6.3 (NEIC)  earthquake also hit the region of the Balleny Islands, south of Australia and New Zealand today. This is probably a strike-slip event and could encourage horizontal motions elsewhere in the world. An earthquake of M 5.7 hit about 100 km south of this epicenter on June 3, 2017 and within about 50 km an M 5.2 occurred on June 7, 2017 but this is the strongest event in the Balleny Islands since an M 6.6 three years ago on October 9, 2012. The antipode to this epicenter is in Iceland at 62N 25W, a seismic area where a moderate earthquake could occur in the next several days.

 

O:  8OCT2017 20:49:03  61.7S  154.5E Mw=6.2  EMSC   BALLENY ISLANDS REGION       

 

The third strong earthquake today occurred in Tonga with M 6.1. Tonga is generally an active region but had not seen any strong earthquakes until today during 2017. The strongest previous in this area this year was an M 5.7 on August 15, 2017.

The last earthquakes of M>=6.1 within about 200 km of this epicenter occurred a year ago on September 24, 2016 with M 6.4 and prior to that on July 6, 2015 (M 6.2).  Forecast 111187 had expected this activity was likely in the Tonga region within about 100 km of this epicenter around October 11.

 

O:  8OCT2017 14:04:41  19.0S  175.8W Mw=6.1  EMSC   TONGA                        

P: 11OCT2017 111187    20.0S  175.0W 4.0-5.5 BAAAA  Tonga Islands              

 

Moderate earthquakes on Mid-Ocean Ridges also occurred in the Mid-Indian Ridge with M 5.4 and on the northern Mid-Atlantic Ridge of M 5.0 occurred. The antipode of the Indian Ridge event is located at 13N 114W south of the Gulf of California.

The area north of this is an active seismic area and may see related seismicity in the next several days.

 

O:  8OCT2017 14:14:12  10.5N   41.3W mb=5.0  EMSC   NORTHERN MID-ATLANTIC RIDGE  

 

O:  9OCT2017 00:28:24  12.7S   66.3E mb=4.9  EMSC   MID-INDIAN RIDGE             

O:  9OCT2017 03:46:52  12.8S   66.3E mb=5.4  EMSC   MID-INDIAN RIDGE             

P: 10OCT2017 111167    17.0S   67.0E 4.0-5.6 ACAAA  So. Indian Ocean           

 

 

 

 

SEISMICITY FOLLOWS HURRICANE NATE

 

EARTHQUAKE SUMMARY FOR OCTOBER 7, 2017

 

The only active tropical storm in the world today - Hurricane Nate - moved northward through Central America and made landfall on the border of Mississippi and Louisiana. A series of moderate earthquakes followed Nate on its path north. These  began in Panama and were most prominent in Costa Rica and Nicaragua with M 4.0-4.5. None of these were widely felt but do illustrate triggering of seismicity by tropical cyclones as noted in previous issues of this report:

 

"Tropical Storm Nate (TD 16) continued off eastern Yucatan, Mexico today with winds up to 50 kts. TS Nate is expected to track to the north reaching the Panhandle of Florida and Alabama around October 8 as a category 1 hurricane. Seismicity in the Nicaragua, Guatemala,  Honduras will probably be elevated over the next three days." (October 5-6, 2017)

 

O:  8OCT2017 03:38:47  12.0N   87.8W mb=4.9  EMSC   NEAR COAST OF NICARAGUA      

O:  8OCT2017 00:30:26  12.1N   87.7W mb=4.2  EMSC   NEAR COAST OF NICARAGUA      

P:  6OCT2017 110990    12.0N   87.0W 3.5-5.2 AAAAA  Nicaragua                  

 

O:  7OCT2017 21:24:08  13.5N   90.5W mb=4.1  EMSC   OFFSHORE GUATEMALA           

P:  7OCT2017 110978    13.0N   90.0W 3.5-5.1 AAAAA  Guatemala                  

 

The strongest earthquake in the U.S. or Canada today was an M 4.2 in Central Alaska. NEIC reported this event was felt with intensity II in Talkeetna and Matanuska-Sustina border, Alaska. The last earthquake within about 100 km of this epicenter was an M 4.6 on August 31, 2017  and prior to that an M 4.2 on May 2, 2017.

Forecast 111150 had expected this earthquake around October 7.

 

O:  7OCT2017 16:07:15  63.1N  151.5W ML=4.2  EMSC   CENTRAL ALASKA               

P:  7OCT2017 111150    61.3N  152.3W 3.2-5.1 ABAAA  Central Alaska             

 

An earthquake of M 2.9 occurred in the area of Central California near San Juan Bautista, California today. NEIC reported this earthquake of M 2.9 in Central California was felt with intensity II-III in the area(s) of San Juan Bautista, Salinas, Watsonville, Sunnyvale, and Pleasanton, California. The last earthquake of M>=2.9 within about 50 km of this epicenter was an M 3.2 on September 20, 2017 at the same epicenter as today's event. Forecast 111029 had expected this earthquake within about 25 km of the epicenter to occur around October 6.

 

O:  7OCT2017 17:27:58  36.6N  121.1W MD=2.6  EMSC   CENTRAL CALIFORNIA           

O:  8OCT2017 01:40:15  36.9N  121.6W MD=2.9  EMSC   CENTRAL CALIFORNIA           

P:  6OCT2017 111029    36.7N  121.4W 2.5-4.4 AAAAA  Central California         

 

Aftershocks continued in the Chiapas/Oaxaca area of Mexico today. The largest of these 13 moderate sized events was an M 4.6-4.8. The strongest event in the region, however was an M 4.7 about 200 km northwest of the aftershock zone in Oaxaca. This is the strongest earthquake within about 100 km of this epicenter since an M 5.0 on May 4, 2007 and prior to that an M 5.0 on September 24, 2005.   NEIC reported this earthquake of M 4.7 in Oaxaca, Mexico was felt with intensity IV in Tlalixtac and Oaxaca, and III in Etla and Santa Lucia del Camino, Oaxaca, Mexico. Forecast 110993 had expected this event in Oaxaca was likely around October 8.

 

O:  8OCT2017 01:21:13  17.3N   96.8W mb=4.7  EMSC   OAXACA, MEXICO               

O: 08OCT2017 01:21:10  16.9N   97.1W ML=4.7  UNAM  l OESTE de CUILAPAM, OAX *: 16.96°

P:  8OCT2017 110993    16.0N   96.0W 3.5-5.1 ABAAA  Oaxaca, Mexico             

 

O: 07OCT2017 22:35:58  15.1N   93.8W ML=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 07OCT2017 08:44:50  15.2N   93.9W ML=4.1  EMSC   OFFSHORE CHIAPAS, MEXICO

O:  7OCT2017 09:05:23  15.1N   93.6W ML=4.3  EMSC   OFFSHORE CHIAPAS, MEXICO     

P: 11OCT2017 110973    15.0N   93.0W 3.5-5.5 BAAAA  Chiapas, Mexico            

 

O: 07OCT2017 12:29:01  15.7N   95.2W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 07OCT2017 12:37:58  15.7N   95.2W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 07OCT2017 05:00:36  15.8N   95.3W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 07OCT2017 16:04:47  16.6N   95.0W mb=4.3  EMSC   OAXACA, MEXICO

O: 07OCT2017 17:02:45  16.7N   94.8W mb=4.3  EMSC   OAXACA, MEXICO

O: 07OCT2017 20:29:01  16.7N   95.2W ML=4.6  EMSC   OAXACA, MEXICO

O:  7OCT2017 04:11:20  17.3N   95.4W ML=4.1  EMSC   OAXACA, MEXICO               

P:  7OCT2017 110975    18.0N   95.0W 3.5-5.2 AAAAA  Chiapas, Mexico            

 

GLOBAL SEISMICITY ACTIVE WITH FULL MOON

 

EARTHQUAKE SUMMARY FOR OCTOBER 6, 2017

 

Global seismicity changed from a quiet to an active state today with the full moon and the end of the geomagnetic storm of late September. This had been expected in the previous issue of this summary. Moderately strong to strong quakes occurred in the South Atlantic (M 5.7); the South Indian Ocean (M 4.7) and Japan (M 5.6, 6.0). Much of this activity could be due to the full moon tidal stresses but some was probably promoted by geomagnetic effects.

 

The strongest earthquake of the day was an M 6.0 off the east coast of Honshu, Japan. It was followed by aftershocks of M 4.6 and 5.7. These were all felt in the area of Fukushima and possibly Tokyo, Japan. The mainshock of M 6.0 was reported by NEIC to have been felt  with maximum intensity V in Iwaki, Fukushima. It wa also felt with intensity II-III in Honshu in the prefectures of Miyagi, Iwate, Fukushima, Ibaraki, Yamagata, Tochigi, Chiba, Saitama, Aomori, Tokyo, Gunma, and Hokkaido as far as about 500 km. The location well off-shore prevented higher intensities and damage. The M 4.6 was reported by NEIC to have been felt with intensity II in Koriyama, Fukushima and in Tokyo. On October 1, this activity had been anticipated in this summary as:

 

"This continues a series of moderate to strong earthquakes in this region off eastern Honshu, Japan and may represent a return to normal seismicity in this region which has been in the stress shadow of the M 9+ quake of March 11, 2011 for the past five years. Forecasts 111055 and 110762 had expected today's activity was likely in late September or early October. The activity in this area in the past week has probably been promoted by concentrated seismic energy from the M 8.2 and aftershocks in Chiapas, Mexico which is located at 103-104 degrees distance. Seismic energy from large earthquakes reflects and refracts off core-mantle boundaries and returns to the surface in this distance range, apparently promoting further seismicity." (October 1, 2017)

 

At the time of the last new moon an M 6.1 earthquake also hit this region off eastern Honshu. It had been linked to the new moon at the time in this summary:

 

" ... the M 8.2 event in Chiapas/Oaxaca, Mexico (in combination with the new moon tidal stresses) appear to have promoted strong earthquakes off the coast of Honshu, Japan (M 6.1) ..." (September 21, 2017)

 

Today's earthquakes off Honshu were most likely promoted by the enhanced tidal stresses with the full moon as were these previous events. Hair triggering of this type suggests there is still much seismic potential in the region which can be triggered by tidal stresses.

 

NEIC reported the aftershock of M 5.4-5.7 was closer to shore and was more widely and strongly felt. Intensity VI was felt in Fukushima at Shirakawa and V in Iwaki, Fukushima. Intensity IV was felt  in Fukushima at Koriyama, Fukushima, and as far as 400 km away in the prefectures of Aomori, Kanagawa, Yamanashi, Iwate, Tokyo, Gunma, Saitama, Niigata, Chiba, Miyagi, Tochigi and Ibaraki, Japan. This earthquake within about 30 minutes of local solar midnight and was probably promoted by tidal stresses associated with the full moon. Forecast 111056 had expected it within about 100 km to occur around October 2. The M 6.0 was located at 104 degrees from the M 8.2 of September 8 in eastern Mexico. As concentrated energy from Mexico has been common in this area over the past month, it was probably also promoted from this source. Other seismicity in this distance range from Mexico today occurred in the Sea of Japan (M 4.3); Guam (M 4.7) and the

Northern Mariana Islands (M 4.5).

 

O:  6OCT2017 14:56:42  37.1N  141.1E Mw=5.6  EMSC   NEAR EAST COAST OF HONSHU, JAP

P:  2OCT2017 111056    38.0N  141.0E 4.0-5.5 BAAAA  Off East Coast Honshu      

 

The last event within about 200 km of the epicenter of the M 6.0 was an M 6.1 on September 20, 2017 with the last new moon and prior to that as an M 6.8 on May 12, 2015. The area showed strong seismic events on March 11, 2011 with the great M>9 subduction zone event and tsunami of that date off Japan. The earthquake of M 6.0 on the outer rise of the subduction zone occurred within about 100 km of forecast 111070 which expected it around October 6.

 

O:  6OCT2017 17:08:00  37.4N  144.0E mb=4.6  EMSC   OFF EAST COAST OF HONSHU, JAPA

O:  6OCT2017 07:59:32  37.5N  144.0E Mw=6.0  EMSC   OFF EAST COAST OF HONSHU, JAPA

P:  6OCT2017 111070    38.0N  145.0E 4.0-5.4 AAAAA  So. of Honshu              

 

O:  6OCT2017 22:30:20  43.1N  138.9E mb=4.3  EMSC   EASTERN SEA OF JAPAN         

P:  4OCT2017 111115    42.0N  137.0E 3.5-5.6 ABBAA  Sea of Japan               

 

A moderately large earthquake of M 5.7 also hit the Tristan da Cunha region of the South Atlantic today. This event was probably promoted by tidal stresses associated with the full moon. The last event within about 200 km of this epicenter with M>=5.7 occurred on July 2, 2015, a regional aftershock of an M 7.0 on June 17, 2015. Prior to that earthquakes hit the region in April, 2011 and 2012. This earthquake was at a right angle from the M 8.2 in Mexico of September 8 (90 degrees node 4) and was probably also promoted from that event and aftershocks.

 

O:  6OCT2017 17:41:26  35.3S   15.7W Mw=5.7  EMSC   TRISTAN DA CUNHA REGION      

 

An earthquake of M 4.7 also occurred in the region of South Indian Ocean near the Kerguelen Islands. As it occurred within minutes of local solar midnight it was probably promoted by the high tidal stresses associated with the full moon. Three earthquakes of M>=4.7 have hit the region in the past 25 years - an M 4.7 on March 15, 2014; an M 4.9 on March 12, 2014 and an M 5.3 on July 28, 2007. This is a remote area and this earthquake was not reported felt in the area. This earthquake is located at 143 degrees from the M 8.2 in Mexico of September 8. Seismic energy from the mainshock and aftershocks reaches this surface distance in  a concentrated form and can help promote additional seismicity at 142-146 degrees. An M 4.5 and M 5.0 in the Andaman Islands of India today was also at 145 degrees from the Mexican epicenter.

 

O:  6OCT2017 18:43:43  49.2S   69.0E mb=4.7  EMSC   KERGUELEN ISLANDS REGION     

O: 06OCT2017 18:43:43  49.2S   68.9E mb=4.7  ANSS   Port-aux-Francais French Southern Territories

 

Seismicity in the Chiapas/Oaxaca area of eastern Mexico saw maximum events of M 4.4 and 4.5. Much of this activity occurred around local solar midnight and noon, suggesting strong tidal triggering of these aftershocks. The M 8.2 mainshock of September 8 was also associated with the full moon but was probably triggered by a strong geomagnetic storm which began at the same time as that earthquake. Forecast 110973 and 110972 expected this activity between

 October 5 and 8.

 

O: 06OCT2017 19:39:29  14.9N   94.1W ML=4.2  UNAM  al SUROESTE de PIJIJIAPAN, CHIS *:

O: 06OCT2017 18:06:32  16.4N   94.9W ML=4.0  UNAM  l ESTE de JUCHITAN DE ZARAGOZA, OA

O: 06OCT2017 10:11:59  16.4N   95.2W ML=4.5  UNAM  l SUROESTE de CD IXTEPEC, OAX *: 1

O: 06OCT2017 06:11:12  14.9N   94.0W ML=4.1  UNAM  al SUROESTE de PIJIJIAPAN, CHIS *:

O: 06OCT2017 05:50:51  16.4N   95.3W ML=4.4  UNAM  l NOROESTE de TEHUANTEPEC, OAX *:

O: 06OCT2017 05:44:03  16.5N   95.2W ML=4.0  UNAM  l SUROESTE de CD IXTEPEC, OAX *: 1

O: 06OCT2017 04:21:18  15.4N   94.8W ML=4.0  UNAM  l SURESTE de SALINA CRUZ, OAX *: 1

O: 06OCT2017 03:53:24  17.5N   94.8W ML=4.2  UNAM  l SURESTE de SAYULA DE ALEMAN, VER

O: 06OCT2017 06:11:12  15.0N   94.0W ML=4.1  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 06OCT2017 18:06:32  16.4N   94.9W ML=4.0  EMSC   OAXACA, MEXICO

O: 06OCT2017 05:50:51  16.4N   95.3W ML=4.4  EMSC   OAXACA, MEXICO

O: 06OCT2017 10:11:59  16.5N   95.2W ML=4.5  EMSC   OAXACA, MEXICO

O:  6OCT2017 19:39:29  14.9N   94.1W ML=4.2  EMSC   OFF COAST OF CHIAPAS, MEXICO 

P:  5OCT2017 110973    15.0N   94.0W 3.5-5.7 AAAAA  Chiapas, Mexico            

P:  8OCT2017 110972    14.0N   94.0W 3.5-5.6 AAAAA  Chiapas, Mexico            

 

The strongest earthquake in the U.S. or Canada today was an M 4.3 in the Rat Islands, Alaska. It was not reported felt in the epicentral area. The last earthquake in the Rat Islands of M>=4.3 was an M 4.8 on September 19, 2017 and prior to that an M 4.6 on August 21, 2017. This occurred with the solar eclipse of August 21. It is likely that today's event and that in August were promoted by strong tidal stresses. Forecast 111139 had expected this earthquake within about 75 km of this epicenter was likely around October 4.

 

O:  6OCT2017 05:56:28  51.6N  178.5E mb=4.3  EMSC   RAT ISLANDS, ALEUTIAN ISLANDS

P:  4OCT2017 111139    51.0N  178.0E 4.0-5.8 AAAAA  Rat Islands                

 

SEISMIC QUIET SHOULD END TODAY

 

EARTHQUAKE SUMMARY FOR OCTOBER 5, 2017

 

Quiet seismic conditions continued today throughout the world. However this condition is likely to end today or tomorrow with the likelihood of strong earthquakes high during the next three days. This is related to the end of a strong geomagnetic storm and by tidal stresses associated with the Full moon which arrived today as noted in previous summaries:

 

"The strongest associated seismicity is likely around October 5-8 with a strong earthquake about 10-15 degrees from the geomagnetic equator or at auroral latitudes is possible during this time period." (October 3-5, 2017)

 

and

 

"The full moon will arrive at 18:40 UT on October 5. Longitudes which are sub-solar at this time include those near 100 West longitude while those at anti-solar are near 80 East longitude. These include the aftershock zones in Mexico and the

Central U.S. and Mesoamerica in the west and Pakistan and India, among others, in Asia. These will experience the maximum tidal stress with this full moon but tidally promoted seismicity is not limited to these areas. Vertical motions including strong subduction zone events will be enhanced during the next seven days through October 8 at least." (October 3-5, 2017)

 

The only earthquake in the world today with M>=5 was an M 5.4 in the area of Antofagasta, northern Chile.  NEIC reported this earthquake of M 5.4 in Northern Chile was felt with intensity IV in Calama, Antofagasta, Chile and II-III in the area(s) of Antofagasta, Chile.  CSN reported this earthquake was felt with intensity V in  Quillagua; IV La Tirana, Calama, Maria Elena, Sierra Gorda, Tocopilla; III   Alto Hospicio, Huara, Iquique, Felt in Tarapaca and Antofagasta.

This is the strongest earthquake in the Antofagasta region of Chile since an M 6.3 on April 15, 2017. A smaller event of M 5.7 hit the region on January 11 and an M 5.4, similar to today's event occurred June 6, 2017. Forecast 111178 had expected this event was likely within about 50 km of this epicenter around October 3.

 

"As Hurricane Irma makes landfall along the east coast of Florida it will push Florida to the north and east with winds and storm surges. The induced motions can affect regional seismicity but much of this motion will be absorbed by the geologic plasticity of the Florida Peninsula. Some effect on seismicity along the western North American subduction zone

as noted above can be expected. But areas along the northern South American subduction zone are also likely to be affected. For example, during the landfall event of October 20, 1921, an earthquake of M 7.1 hit southern Peru and northern Chile in the Tarapaca area (also on October 20). In that hurricane no major effects were noted in the Mexican or California regions to seismicity. In general, with the exception of the northern South American subduction zone there is little evidence that landfall in the Tampa area of Florida is highly promotional to regional seismicity patterns." (September 9, 2017)

 

Forecast 111178 expected this earthquake within about 50 km of this epicenter was likely around October 3 in association with the full moon. This earthquake is located at the seventh node (51 degrees) from the M 7.1 in Puebla, Mexico of September 19 and may have been promoted from that source.

 

O:  5OCT2017 08:11:35  22.4S   68.4W Mw=5.4  EMSC   ANTOFAGASTA, CHILE           

O:  5OCT2017 08:11     22.4S   68.6W mb=5.5  GUC    Quillagua; IV La Tirana, Calam

P:  3OCT2017 111178    22.0S   69.0W 4.0-5.6 AAAAA  Coast No. Chile            

 

The aftershocks sequence in Chiapas and Oaxaca, Mexico continued today at a reduced level. The strongest event was an M 4.3 off the coast of Oaxaca. Strong tidal stresses associated with the full moon may encourage a stronger quake

in the next two days.

 

O: 05OCT2017 18:22:16  15.6N   94.8W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 05OCT2017 12:34:25  15.8N   95.1W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 05OCT2017 20:40:17  16.0N   95.3W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 05OCT2017 17:10:01  16.5N   95.0W ML=4.0  EMSC   OAXACA, MEXICO

O: 05OCT2017 04:55:18  17.2N   95.2W ML=4.4  EMSC   OAXACA, MEXICO

O:  5OCT2017 14:38:09  15.3N   94.6W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO      

P:  4OCT2017 110993    15.0N   96.0W 3.5-5.3 AAAAA  Oaxaca, Mexico              

P:  5OCT2017 110973    15.0N   94.0W 3.5-5.7 AAAAA  Chiapas, Mexico            

P:  7OCT2017 110974    15.0N   95.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

 

UNUSUAL ANTIPODAL PAIR IN MID-INDIAN RIDGE; GULF OF CALIFORNIA

 

EARTHQUAKE SUMMARY FOR OCTOBER 4, 2017

 

An unusual near-antipodal pair occurred today, first in the mid-Indian Ridge with M 4.8 and about an hour later in the Gulf of California (M 4.1, 4.2). This event of M 4.8 was the strongest in the world today (along with an M 4.8 aftershock in Oaxaca, Mexico). The mid-Indian event was not reported felt in this oceanic region. It occurred near local solar midnight and was likely promoted by strong tidal stresses associated with the full moon today. The last event of M>=4.8 within about 200 km of this epicenter under the Indian Ocean was an M 4.8 on March 28, 2017. The last of larger magnitude was an M 5.2 on November 10, 2014. Two events of M 4.8-4.9 hit the region in 2016 about 250 km northwest of today's epicenter.  Forecast 111184 expected a moderate earthquake in this region around October 8.

 

O:  4OCT2017 18:48:03  22.9S   69.3E mb=4.8  EMSC   MID-INDIAN RIDGE             

P:  8OCT2017 111184    28.0S   66.0E 4.0-5.7 BCCAA  So. Indian Ocean           

 

This earthquake in the Indian Ocean area occurred at 23S 69E within about 200 km of exact antipodal of two later events in the Gulf of California of M 4.2 and 4.1 at 23N 109W. Forecast 111006 had expected these events in the Gulf of California were likely around October 11 within about 25 km of these epicenters. The antipodal relation of these events is unknown but as they occurred about 50 minutes apart with the Gulf of California event near local solar noon, prime time for tidal triggering, it may be coincidental caused by strong tidal stresses at both points.

 

O:  4OCT2017 19:37:14  23.8N  108.6W mb=4.1  EMSC   GULF OF CALIFORNIA           

O: 04OCT2017 19:37:21  23.8N  108.8W ML=4.2  UNAM  al NORESTE de SAN JOSE DEL CABO, B

O:  5OCT2017 00:28:47  24.2N  108.5W ML=4.1  EMSC   GULF OF CALIFORNIA           

P: 11OCT2017 111006    24.0N  109.0W 3.5-5.0 CAAAA  Gulf of California         

 

 

Several of today's aftershocks in the Chiapas/Oaxaca aftershock zone were lightly felt. This included an M 4.3 felt at Tehuantepec, Oaxaca. The largest aftershock today was an M 4.8 off the coast of Chiapas, Mexico, one of the two largest events in the world today.

 

O: 04OCT2017 07:34:11  15.0N   94.1W mb=4.8  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 04OCT2017 23:15:29  15.0N   94.3W ML=4.2  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 04OCT2017 19:02:04  15.2N   94.7W ML=4.3  EMSC   OFF COAST OF OAXACA, MEXICO

O: 04OCT2017 10:39:37  15.4N   94.7W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 05OCT2017 00:30:41  15.4N   94.8W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 04OCT2017 05:20:13  15.6N   95.3W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 04OCT2017 21:05:44  15.7N   94.5W mb=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 04OCT2017 15:17:50  15.9N   94.8W mb=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 05OCT2017 03:28:55  16.1N   95.3W ML=4.1  EMSC   OAXACA, MEXICO

O: 04OCT2017 18:53:35  16.4N   95.1W ML=4.1  EMSC   OAXACA, MEXICO

O: 04OCT2017 22:21:51  16.4N   95.1W ML=4.1  EMSC   OAXACA, MEXICO

O: 05OCT2017 03:36:42  16.5N   95.1W ML=4.2  EMSC   OAXACA, MEXICO

O: 04OCT2017 18:45:21  16.7N   95.0W mb=4.3  EMSC   OAXACA, MEXICO

 

The strongest earthquake in the U.S. or Canada today was an M 4.3 in the Kodiak Island region of Alaska. An M 5.5 in the area occurred on August 31 and this is probably the largest aftershock of that event to date. Forecast 111147  expected a light to moderate event in this region around October 4.

 

NEIC reported this earthquake of M 4.3 in Kodiak, Southern Alaska was felt with intensity II-III in the area(s) of Kodiak and Homer, Alaska.

 

O:  5OCT2017 02:03:58  58.4N  152.9W ML=4.3  EMSC   KODIAK ISLAND REGION, ALASKA 

P:  4OCT2017 111147    60.1N  153.4W 3.2-4.9 ABAAA  Central Alaska             

 

The strongest earthquakes in the U.S. outside Alaska today occurred in Oklahoma with M 3.5 and 3.6. These are not unusual earthquakes and occur frequently. They  are a bit larger than typical background at this time. The last events of M>=3.5 in Oklahoma occurred as an M 3.8 on September 24, 2017 and M 4.3 with the last full moon on September 8, 2017.

 

Forecast 111074 had expected this activity around October 7. It is likely the increased magnitude was promoted by tidal stresses associated with the full moon of today.

 

O:  4OCT2017 22:06:44  36.5N   98.7W mb=3.5  EMSC   OKLAHOMA                     

O:  5OCT2017 00:51:38  36.5N   98.8W mb=2.6  EMSC   OKLAHOMA                     

O:  5OCT2017 00:12:01  36.5N   98.8W mb=3.4  EMSC   OKLAHOMA                     

P:  7OCT2017 111074    37.0N   98.0W 2.0-4.0 AAAAA  Southern Plains            

 

An M 2.7 earthquake occurred in the area south of San Francisco, California today and was followed by a series of foreshocks and aftershocks. Two of these occurred near local noon and my have been promoted by tidal stresses associated with the full moon today. This area near Aromas, California has been showing increased seismicity in recent months most of which is associated with new or full moons. The last quake within about 50 km of this epicenter with M>=2.7 occurred on September 20 with M 3.2. An M 2.9 also hit this area on August 23. Forecast 111029 had expected this event within about 25 km  of this epicenter

 

NEIC reported this earthquake of M 2.7 in Central California was felt with intensity II-III in the area(s) of Aromas, Salinas, Watsonville, Santa Cruz, San Jose, Santa Clara, and possibly Berkeley, California.

 

O:  4OCT2017 19:05:03  36.5N  121.1W MD=2.0  EMSC   CENTRAL CALIFORNIA           

O:  4OCT2017 19:01:10  36.5N  121.1W MD=2.2  EMSC   CENTRAL CALIFORNIA           

O:  4OCT2017 06:51:39  36.7N  121.2W MD=2.1  EMSC   CENTRAL CALIFORNIA           

O:  4OCT2017 15:58:38  36.9N  121.6W MD=2.7  EMSC   CENTRAL CALIFORNIA           

P:  6OCT2017 111029    36.7N  121.4W 2.5-4.4 AAAAA  Central California         

 

Moderate earthquakes also continued today in the area north of Costa Rica.  These followed a similar event yesterday as reported in this summary:

 

"To the south of Mexico a tropical depression (16) formed today north of  Panama.  NHC has given this system 70% probability of becoming a tropical cyclone in the next two days. It is currently near 10N 80W with winds up to 25 kts. An earthquake in Panama of M 4.6 was probably promoted by this disturbance. A similar event of M 4.5 hit the area on September 5. Forecast 110935 had expected this event was likely around October 9 within about 50 km of this epicenter." (October 3-4, 2017)

 

Tropical Depression 16 formed off the the north coast of Costa Rica and Panama today with winds up to 35 kts. Two earthquake in Panama of M 4.1 and 4.2 was probably felt in Costa Rica and Panama near the eye of this storm was promoted by this disturbance. TD 16 is expected to track to the north reaching the Panhandle of Florida and Alabama around October 8 as a category 1 hurricane. Seismicity in the Costa Rica, Nicaragua, Panama and Honduras will probably be elevated over the next three days. A moderate earthquake in these areas and possibly in northern Colombia could occur in conjunction with the full moon and this storm.

 

O:  4OCT2017 15:13:00   8.8N   84.3W ML=3.9  EMSC   OFF COAST OF COSTA RICA      

O:  5OCT2017 02:00:00   8.8N   84.3W ML=4.1  EMSC   OFF COAST OF COSTA RICA      

P:  9OCT2017 110935     8.0N   83.0W 3.5-5.2 BAAAA  Costa Rica                  

 

MODERATELY STRONG QUAKE IN NORTH ATLANTIC

 

EARTHQUAKE SUMMARY FOR OCTOBER 3, 2017

 

A moderately large earthquake of M 5.7-5.8 occurred today in the North Atlantic area about 1000 km east of the Leeward and Windward Islands. This is a remote area and this event was not reported felt in the epicentral area west of the mid-ocean ridge. The area has seen some unusual activity over the past year but had previously been relatively quiet. The only comparable earthquake in at least 25 years occurred at this epicenter on July 27, 2017 with M 6.0. At the time this summary  reviewed the recent seismic history of the area as:

 

"This is an unusual epicenter as it does not really lie on the Mid-Atlantic Ridge but far to the west of that feature. It is too large for simple volcanic feature collapse, and is in an area which does not normally see this magnitude seismicity. The only event in the past 25 years of M>=5.9 in the region within about 500 km of this epicenter was an M 5.9 on October 1, 1998 about 500 km to the east of today's event. The only event off the ridge of M>=5.9 ever recorded was an M 7.2 on December 1, 1950 but this too, was about 200 km east of today's epicenter. Forecast 109144 had expected this event was likely on the Mid-Atlantic Ridge around July 29. This epicenter is located at 104 degrees from the great M 7.7 quake in the Komandorsky Islands of July 17, 2017. This is a distance at which triggering is expected due to concentrated seismic energy at the surface following major earthquakes." (July 28, 2017)

 

Forecast 110989 had expected this event was likely within about 300 km of this epicenter around October 5.

 

O:  3OCT2017 20:39:04  13.5N   49.2W Mw=5.7  EMSC   NORTH ATLANTIC OCEAN         

O: 03OCT2017 20:39:05  13.4N   49.4W mb=5.8  ANSS   North Atlantic Ocean"

P:  5OCT2017 110989    15.0N   46.0W 4.0-5.8 ABCAA  Mid-Atlantic Ridge         

 

The strongest aftershock in the Chiapas, Mexico aftershocks zone was an M 4.8 among a dozen other events of M>=4. This continues to be an active zone with the potential for a larger event with the full moon tomorrow. As expected  some of the activity in Mexico today moved to the Guerrero and Michoacan areas where an M 4.6 occurred. A tropical disturbance off southern Chiapas continues to dampen larger aftershocks in the area at this time.

 

O: 04OCT2017 07:34:13  15.1N   94.0W mb=4.8  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 03OCT2017 06:32:35  15.2N   94.1W ML=4.4  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 03OCT2017 22:02:28  15.3N   94.7W ML=4.2  EMSC   OFF COAST OF OAXACA, MEXICO

O: 03OCT2017 11:16:03  15.4N   94.8W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 04OCT2017 05:20:13  15.6N   95.3W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 04OCT2017 00:21:56  15.9N   96.4W ML=4.0  EMSC   OAXACA, MEXICO

O: 04OCT2017 01:04:29  16.3N   95.3W ML=4.3  EMSC   OAXACA, MEXICO

O: 03OCT2017 13:10:12  16.5N   95.0W ML=4.0  EMSC   OAXACA, MEXICO

O: 03OCT2017 19:03:37  16.5N   95.1W ML=4.1  EMSC   OAXACA, MEXICO

O:  3OCT2017 18:16:08  16.5N   95.1W ML=4.3  EMSC   OAXACA, MEXICO               

P:  2OCT2017 110975    17.0N   94.0W 3.5-5.6 AAAAA  Chiapas, Mexico            

P:  4OCT2017 110993    15.0N   96.0W 3.5-5.3 AAAAA  Oaxaca, Mexico             

P:  5OCT2017 110973    15.0N   94.0W 3.5-5.7 AAAAA  Chiapas, Mexico            

 

O:  3OCT2017 06:02:50  18.6N  101.4W ML=4.1  EMSC   MICHOACAN, MEXICO            

O: 04OCT2017 03:16:26  19.1N  102.7W ML=4.6  UNAM   ESTE de TEPALCATEPEC, MICH *: 19.

O:  4OCT2017 03:16:26  19.2N  102.8W ML=4.6  EMSC   MICHOACAN, MEXICO            

P:  3OCT2017 110987    18.0N  101.0W 3.5-5.1 ABBAA  Michoacan, Mexico          

 

To the south of Mexico a tropical depression (18) formed today north of Panama.  NHC has given this system 70% probability

of becoming a tropical cyclone in the next two days. It is currently near 10N 80W with winds up to 25 kts. An earthquake in Panama of M 4.6 was probably promoted by this disturbance. A similar event of M 4.5 hit the area on September 5. Forecast 110935 had expected this event was likely around October 9 within about 50 km of this epicenter.

 

NEIC reported this earthquake of M 4.2 in Panama was felt with intensity II-III in the area(s) of Chiriqui, Panama at Guarumal, David and Boquete.

 

O:  3OCT2017 23:43:58   8.6N   82.8W mb=4.2  EMSC   PANAMA-COSTA RICA BORDER REGIO

P:  9OCT2017 110935     8.0N   83.0W 3.5-5.2 CAAAA  Costa Rica                 

 

The strongest earthquake in the U.S. or Canada today was an M 4.1 in the Alaska Peninsula. The last earthquake of larger magnitude in this area within about 100 km of this epicenter was an M 5.2 on May 28, 2017. Forecast 111144 had expected this event within about 25 km of this epicenter around October 2.

 

NEIC reported this earthquake of M 4.1 in the Alaskan Peninsula was felt with intensity II-III in the area(s) of Cold Bay, Alaska.

 

O:  3OCT2017 06:59:27  54.6N  161.4W ML=4.1  EMSC   ALASKA PENINSULA             

P:  2OCT2017 111144    54.3N  161.4W 3.5-4.9 AAAAA  Unimak Islands, Aleutians  

 

ANTIPODAL PAIR COMPLETED IN SUMARTA; COLOMBIA

 

EARTHQUAKE SUMMARY FOR OCTOBER 2, 2017

 

The antipodal pair in Colombia and Sumatra was completed today with an M 4.6 south of Sumatra. This follows an M 5.1-5.7 in Colombia of October 1. In that summary it had been noted:

 

"Moderate to strong earthquakes in this area (Colombia) often pair with similar events in the area south of Sumatra. On September 25, 2017 an M 5.1 did hit within about 100 km of the antipode of the Colombia epicenter at 6S 106.5E (compare with 7N 73.5W for antipode)." (October 1, 2017)

 

Forecast 110677 had expected today's Sumatra earthquake was likely at the end of September or early October within about 100 km of this epicenter.

 

O:  2OCT2017 18:46:34   7.0S  102.3E mb=4.6  EMSC   SOUTHWEST OF SUMATRA, INDONESI

O: 02OCT2017 18:46:35   7.1S  102.4E mb=4.6  ANSS   SW of Biha Indonesia

P: 27SEP2017 110677     6.0S  102.0E 4.0-5.5 BAAAA  So. of Sumatera            

 

O: 01OCT2017 01:35:26   7.5N   73.1W mb=5.1  ANSS   El Playon Colombia

O:  1OCT2017 01:35:24   7.5N   73.1W Mw=5.7  EMSC   NORTHERN COLOMBIA            

P:  1OCT2017 110934     7.0N   73.0W 4.0-5.8 AAAAA  Colombia                   

 

The strongest earthquake of the day was an M 5.3 in southern Vanuatu. This event, while not reported felt in this remote area, occurred at 103 degrees from the great M 8.2 in Chiapas Mexico of September 8, in a pattern discussed in previous issues of this report. Seismic energy is concentrated at this distance by reflection and refraction off core-mantle boundaries following strong earthquakes and this nearly month-long daily moderate to strong aftershocks. This destabilized the area near 103 degrees from Chiapas helping to promote seismic events such as today's earthquake and the eruption of volcanoes to the north, also in Vanuatu as described in the previous issue of this summary. Today's earthquake had been expected within about 100 km of the epicenter  in forecast 111189 around October 2.

 

O:  2OCT2017 21:37:56  19.5S  167.7E mb=5.3  EMSC   VANUATU REGION               

O: 02OCT2017 21:37:57  19.5S  167.7E mb=5.3  ANSS   W of Isangel Vanuatu

P:  2OCT2017 111189    20.0S  169.0E 4.0-5.5 AAAAA  Vanuatu Islands            

 

Aftershocks also continued today in the region of Chiapas and Oaxaca, Mexico. The strongest today was M 4.9. An earthquake of M 4.1 in Michoacan, Mexico today may signal a possible moderate earthquake in the area corresponding with the full moon.

 

The full moon will arrive at 18:40 UT on October 5. Longitudes which are sub-solar at this time include those near 100 West longitude while those at anti-solar are near 80 East longitude. These include the aftershock zones in Mexico and the

Central U.S. and Mesoamerica in the west and Pakistan and India, among others, in Asia. These will experience the maximum tidal stress with this full moon but tidally promoted seismicity is not limited to these areas. Vertical motions including strong subduction zone events will be enhanced during the next seven days through October 8 at least.

 

Forecast 110987 had expected the Michoacan quake was likely around October 3.

 

O:  3OCT2017 06:02:50  18.6N  101.4W ML=4.1  EMSC   MICHOACAN, MEXICO            

O: 03OCT2017 06:02:50  18.5N  101.3W ML=4.1  UNAM  l OESTE de HUETAMO, MICH *: 18.56°

P:  3OCT2017 110987    18.0N  101.0W 3.5-5.1 AAAAA  Michoacan, Mexico          

 

O: 03OCT2017 05:30:33  15.4N   93.9W mb=4.9  ANSS   Tres Picos Mexico

O: 02OCT2017 22:56:53  15.0N   94.3W ML=4.2  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 03OCT2017 05:30:32  15.4N   94.0W mb=4.9  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 02OCT2017 12:13:26  15.6N   95.0W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 03OCT2017 04:52:12  15.7N   95.2W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 02OCT2017 08:10:58  15.7N   95.3W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O:  3OCT2017 06:32:28  14.9N   94.3W ML=4.6  EMSC   OFF COAST OF CHIAPAS, MEXICO 

P:  4OCT2017 110993    15.0N   96.0W 3.5-5.3 AAAAA  Oaxaca, Mexico             

P:  5OCT2017 110973    15.0N   94.0W 3.5-5.7 AAAAA  Chiapas, Mexico             

 

O: 02OCT2017 10:39:35  16.1N   94.8W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 03OCT2017 05:39:14  16.1N   95.7W ML=4.4  EMSC   OAXACA, MEXICO

O: 02OCT2017 13:40:07  16.4N   94.9W ML=4.1  EMSC   OAXACA, MEXICO

O: 02OCT2017 07:53:03  16.4N   95.1W ML=4.2  EMSC   OAXACA, MEXICO

O:  2OCT2017 08:41:08  16.7N   94.9W mb=4.3  EMSC   OAXACA, MEXICO               

P:  2OCT2017 110975    17.0N   94.0W 3.5-5.6 AAAAA  Chiapas, Mexico            

 

O:  3OCT2017 06:32:28  14.9N   94.3W ML=4.6  EMSC   OFF COAST OF CHIAPAS, MEXICO 

P:  4OCT2017 110993    15.0N   96.0W 3.5-5.3 AAAAA  Oaxaca, Mexico             

P:  5OCT2017 110973    15.0N   94.0W 3.5-5.7 AAAAA  Chiapas, Mexico            

 

O:  2OCT2017 08:41:08  16.7N   94.9W mb=4.3  EMSC   OAXACA, MEXICO                

P:  2OCT2017 110975    17.0N   94.0W 3.5-5.6 AAAAA  Chiapas, Mexico            

 

Light earthquakes also continued in the eastern U.S. today. The largest of these was an M 2.2 in southeastern Missouri on the New Madrid Fault zone.  Minor quakes were also reported in South Carolina (M 1.9); Arkansas (M 1.7);

New Hampshire (M 1.4). These represent normal background seismicity. It has been nearly 1.5 months since the total solar eclipse on August 21 triggered a series of light to moderate earthquakes nearly daily along the solar eclipse path in the following two weeks. But this triggering now appears to have dissipated.

 

O:  2OCT2017 15:12:39  36.6N   89.8W MD=2.2  EMSC   SOUTHEASTERN MISSOURI        

P:  4OCT2017 111047    36.3N   89.5W 2.0-4.1 AAAAA  New Madrid area            

 

O:  2OCT2017 06:32:03  35.0N   82.9W md=1.9  ANSS   Pickens South Carolina       

P:  3OCT2017 111040    35.0N   82.0W 2.0-4.3 AAAAA  Kentucky/Tennessee/NC      

 

O:  2OCT2017 09:31:47  35.9N   90.1W md=1.7  ANSS   E of Manila Arkansas         

P: 29SEP2017 110755    36.7N   89.7W 2.0-4.4 BAAAA  New Madrid area            

 

O:  2OCT2017 08:12:38  43.7N   71.3W ml=1.4  ANSS   Tuftonboro New Hampshire     

P:  5OCT2017 111095    43.0N   70.0W 2.0-4.2 BAAAA  Maine                       

 

O: 29SEP2017 05:06:30  47.5N   70.1W ML=1.2  NRCA  CHARLEVOIX SEISMIC ZONE       

P: 29SEP2017 110808    47.3N   70.5W 2.0-3.9 AAAAA  New England                

 

EVACUATIONS IN VANUATU BEGIN FOLLOWING ERUPTION ON AMBAE ISLAND

 

EARTHQUAKE SUMMARY FOR OCTOBER 1, 2017

 

Manaro Voui volcano on Ambae, northern Vanuatu erupted today. This eruption triggered the evacuation by sea of nearly 11,000 residents of the island of Ambae, Vanuatu. Many have taken residence in emergency shelters pending evacuation.

The eruption polluted water supplies on Ambae, leaving no drinkable water on the island. Ambae volcano is located at 15.4S 167.8E. Volcanoes Ambrym and Lopevi in Vanuatu are also active at this time. Like much of the other strong seismicity in the world in the past month, this volcano is located at 102-103 degrees from the great M 8.2 earthquake in

Chiapas, Mexico of September 8. Seismic energy from large events reflects off and refracts off of core-mantle boundaries and returns to the surface at this distance range. It is likely that this volcanic eruption and other seismicity in Vanuatu in recent days was promoted by this energy from the Mexican earthquake. This had previously been noted in this summary as follows:

 

"NEIC reported the M 6.4 in Vanuatu was probably felt with intensity IV and reported with intensity III in Vila, Shefa, Vanuatu. The M 6.4 was preceded by an M 4.7 in central Vanuatu about five hours earlier. That event was at 103 degrees from the M 8.2 Mexican shock. It only takes a nudge. ...  Today's epicenter is located at 101-102 degrees from the great M 8.2 quake in  Mexico of September 8. As noted above this probably was promoted by concentrated energy reflected to this distance on the surface. It only takes a nudge." (September 21, 2017)

 

Ambae, Vanuatu also lies within a few degrees of the geomagnetic equator and the recent geomagnetic storm probably had abetted the eruption at that site as noted in previous summaries:

 

"Some seismicity near the equator and poles may increase in the next day but major increases are more likely  October 4-6, about 4-5 days after the current storm becomes inactive." (October 1, 2017)

 

The largest earthquake in the U.S. or possessions today was an M 4.4 in Puerto Rico. NEIC reported it was felt with intensity II-III in Mayaguez, Puerto Rico. Puerto Rico has recently seen great destruction from hurricanes and damage from  a large earthquake is not a pleasant alternative. But hurricanes and bring about conditions which encourage seismicity and many of the strongest earthquakes in Puerto Rico have occurred during hurricane season. The last earthquake in Puerto

Rico of M>4.4 was an M 4.9 on  August 18, 2017. Two other such events have occurred in this island during 2017 - an M 4.7 on July 17 and an  M 4.6 on August 14. Forecast 110996 had expected today's event was likely around October 1.

 

O:  1OCT2017 08:57:43  18.5N   67.8W mb=4.4  EMSC   MONA PASSAGE, PUERTO RICO    

P:  1OCT2017 110996    18.0N   67.0W 3.4-4.9 AAAAA  Puerto Rico                

 

MODERATELY STRONG QUAKES STRIKE ALONG EQUATOR

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 30, 2017

 

A pair of moderately strong earthquakes struck along the earth's equator today. These included an M 5.1-5.7 in northern Colombia and an M 5.5 in Halmahera, Indonesia. These were probably promoted by the geomagnetic storm which began three days ago and is still in progress.

 

The strongest earthquake of the day was an M 5.1 (NEIC) to M 5.7 (EMSC) quake in northern Colombia. Due to its intermediate depth and magnitude it was widely felt in Colombia. NEIC reported maximum intensity IV in Colombia at Cucuta, Bucaramanga, Santander, and II-III within about 400 km of the epicenter in Colombia at Floridablanca, Pamplona, San Cristobal, Soata, Sogamoso, San Alberto, Tunja, Rionegro, Medellin, Cajica, Envigado, Chia, Sabaneta, Itagui, Cota, La Calera, Bogota, Pereira, Cartagena and Barranquilla, Colombia.  Moderate to strong earthquakes in this area often pair with similar events in  the area south of Sumatra. On September 25, 2017 an M 5.1 did hit within about 100 km of the antipode of the Colombia epicenter at 6S 106.5E (compare with 7N 73.5W for antipode). This followed signs of a possible eruption in this area of  Indonesia two days before as noted in this summary:

 

"An imminent eruption of Agung Volcano in Bali, Indonesia has caused the evacuation of more than 50,000 from areas surrounding the volcano. The last eruption of Agung was in 1963.  That eruption killed more than 1000 people but evacuation procedures were not as sophisticated in that event 54 years ago. More than 1000 earthquakes have been recorded in the past several days in the region including several of moderate magnitude. Agung is Bali's largest volcano." (September 25, 2017)

 

Further seismicity near the Sumatra site may be promoted from today's Colombia event. The earthquake in Colombia may have also been promoted by the current geomagnetic storm. This summary had expected this in the previous issue  as:

 

"Some seismicity near the equator and poles may increase in the next day but major increases are more likely after the first of October, about 4-5 days after the current storm becomes inactive." (September 29-30, 2017)

 

This is the strongest earthquake in Northern Colombia during the year 2017, surpassing in size the M 5.0 on August 8, 2017. The last event of M>=5.1 in Northern Colombia within about 200 km of today's epicenter was an M 5.3 nearly two years ago on November 7, 2015. The last of M>=5.7 was an M 6.2 on March 10, 2015. Forecast 110934 had expected today's event within about 50 km of this epicenter around October 1.

 

O: 01OCT2017 01:35:26   7.5N   73.1W mb=5.1  ANSS   El Playon Colombia

O:  1OCT2017 01:35:24   7.5N   73.1W Mw=5.7  EMSC   NORTHERN COLOMBIA            

P:  1OCT2017 110934     7.0N   73.0W 4.0-5.8 AAAAA  Colombia                   

 

The earthquake in Colombia occurred 10 minutes after the third strongest event of the day - an M 4.9 in Ibaraki, Japan. NEIC reported this event in Japan was felt with intensity II-III in Ibaraki at Mito, Utsunomiya, Tsukuba, Chiyoda, Tsuchiura, Naka, and in Tokyo, Sendai, Miyagi, Kasukabe, Saitama and Sano, Tochigi, Japan. This continues a series of moderate to strong earthquakes in this region off eastern Honshu, Japan and may represent a return to normal seismicity in this region which has been in the stress shadow of the M 9+ quake of March 11, 2011 for the past five years. Forecasts 111-55 and 110762 had expected today's activity was likely in late September or early October. The activity in this area in the past week has probably been promoted by concentrated seismic energy from the M 8.2 and aftershocks in Chiapas, Mexico which is located at 103-104 degrees distance. Seismic energy from large earthquakes reflects and refracts off core-mantle boundaries and returns to the surface in this distance range, apparently promoting further seismicity.

 

O:  1OCT2017 01:25:07  36.9N  140.5E mb=4.9  EMSC   NEAR EAST COAST OF HONSHU, JAP

P:  3OCT2017 111055    36.0N  142.0E 4.0-5.4 AAAAA  Off East Coast Honshu      

P: 27SEP2017 110762    37.0N  141.0E 4.0-5.8 BAAAA  Off East Coast Honshu      

 

After a series of moderate and light earthquakes in Halmahera, Indonesia over the past several days events of M 5.5 and M 5.3 occurred today. These occurred  north and east of the series of M 4.7-4.8 quakes of September 28 ih Halmahera.

BMG reported an M 5.2-5.3 was felt with intensity III-IV in Morotai, Halmahera Timur, Tobelo, and III in Halmahera Utara, Indonesia. The event of M 5.5 north of Halmahera was not immediately reported felt. An M 5.6 occurred near the northern event on January 1, 2017, the largest previous quake in this area. A similar M 5.6-5.7 hit south of this on January 21, 2017. Forecast 110937 had expected this activity was likely in early October. 

 

O: 30SEP2017 10:30:01  01.8N  128.8E MS=5.2  BMG  Felt with intensity III-IV in Morotai, Halmahera Timur, Tobelo, and III in Halmahera Utara, Indonesia.

O: 30SEP2017 10:30:02   2.0N  128.8E mb=5.3  EMSC   HALMAHERA, INDONESIA         

P:  4OCT2017 110937     3.0N  128.0E 4.0-5.4 BAAAA  Halmahera                  

 

O: 30SEP2017 23:15:33   3.9N  128.6E Mw=5.5  EMSC   NORTH OF HALMAHERA, INDONESIA

P:  4OCT2017 110937     3.0N  128.0E 4.0-5.4 AAAAA  Halmahera                  

 

Aftershocks also continued in the area of Chiapas and Oaxaca today. Most of those of M>=4 were occurred in the Oaxaca region. This represents a shift to the west of the major aftershock zone over the past week from Chiapas to Oaxaca.

 

O: 30SEP2017 09:00:56  15.3N   94.8W ML=4.1  EMSC   OFF COAST OF OAXACA, MEXICO

O: 30SEP2017 09:48:38  15.4N   94.1W mb=4.4  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 30SEP2017 18:31:40  15.4N   94.8W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 30SEP2017 19:23:35  15.8N   95.1W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 30SEP2017 12:18:11  15.9N   95.1W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 30SEP2017 18:15:50  16.3N   94.7W mb=4.7  EMSC   OFFSHORE OAXACA, MEXICO

O: 30SEP2017 09:20:31  16.4N   95.1W ML=4.0  EMSC   OAXACA, MEXICO

O: 01OCT2017 02:53:14  16.4N   95.2W ML=4.1  EMSC   OAXACA, MEXICO

O: 30SEP2017 12:56:29  16.4N   95.2W ML=4.1  EMSC   OAXACA, MEXICO

O: 30SEP2017 22:45:25  16.8N   95.4W ML=4.1  EMSC   OAXACA, MEXICO               

P:  2OCT2017 110975    16.0N   94.0W 3.5-5.8 AAAAA  Chiapas, Mexico             

P: 30SEP2017 110687    17.0N   94.0W 3.5-5.6 AAAAA  Chiapas, Mexico            

 

The strongest earthquake in the U.S. or Canada today was once again in the Yunaska, Fox Islands region of Alaska's Aleutians. This event of M 4.3 was larger but not as widely felt as an M 4.1 in Southern Alaska near Homer and Anchor Point. Forecast 110841 had expected the event in the Fox Islands within about 50 km  of that epicenter whereas the event in Southern Alaska had  been expected in forecast 111147.

 

O:  1OCT2017 00:05:28  52.0N  170.0W mb=4.3  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O: 01OCT2017 00:05:28  52.0N  169.9W mb=4.3  ANSS   Yunaska Island Alaska

P: 30SEP2017 110841    51.9N  169.2W 3.5-5.1 AAAAA  Fox Islands, Aleutians     

 

NEIC reported the earthquake of M 4.1 in Southern Alaska was felt with intensity II-III in the area(s) of Homer and possibly Anchorage, Alaska.

 

O: 30SEP2017 21:15:06  59.6N  152.2W ML=4.1  EMSC   SOUTHERN ALASKA              

P:  1OCT2017 111147    60.1N  150.6W 3.2-5.0 AAAAA  Central Alaska             

 

MODERATE QUAKE SHAKES SICHUAN, CHINA

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 29, 2017

 

The strongest earthquake in the world today was an M 5.5 in Sichuan, China. NEIC reported maximum intensity IV in Sichuan at Nanchong and II-III in Mianyang, Dawan, Chengdu and Huayang, China. No damage was immediately reported with this earthquake but reports from China are often delayed and it is likely that damage and loss of property occurred in this earthquake in Sichuan. This event may have been promoted by the current geomagnetic which, like this events, maximizes near local solar noon. A large M 6.5 hit about 150 km northwest of this on August 8. Foreshocks to today's event may have included an M 4.9 on July 16, 2007. Forecast 110721 had expected today's earthquake was likely to the south around September 28.

 

O: 30SEP2017 06:14:39  32.3N  105.1E Mw=5.5  EMSC   SICHUAN-GANSU BORDER REG, CHIN

O: 30SEP2017 06:14:36  32.3N  105.0E mb=5.5  ANSS   WSW of Magong China

P: 28SEP2017 110721    28.0N  104.0E 4.0-5.4 ACAAA  Myanmar                    

 

An earthquake of M 4.6 also shook Central Turkey today. NEIC reported intensity II in Antalya, Turkey at Serik and Manavgat, Turkey. No major damage or casualties were reported. This continues the activation of western Turkey which has included a strong earthquake in the Dodecanese Islands of Greece. Most of this activity is occurring at 103 degrees from Chiapas, Mexico and may be promoted by concentrated seismic energy from that region. The last earthquake of M>=4.6 within about 200 km of today's epicenter occurred as an M 4.7  on October 19, 2016 and prior to that an M 5.4 on October 6, 2015. Most moderate earthquakes in this region occur in the autumn between August and October and may be driven by meteorological stresses. Forecast 110786 expected a moderate earthquake in this area around September 29.

 

O: 29SEP2017 16:08:40  37.0N   30.7E mb=4.6  EMSC   WESTERN TURKEY               

P: 29SEP2017 110786    39.0N   31.0E 3.5-5.1 ABAAA  Turkey                     

 

An earthquake of M 5.0 (EMSC) to M 5.4 (GEONET) also occurred near Opotiki, North Island today. GEONET reported this earthquake was felt with weak intensity in the area of northern North Island,  New Zealand. 46 people reported feeling this earthquake with 37 of weak intensity and 9 with light intensity in North Island, New Zealand; none felt the quake with strong to severe intensity. The last and only earthquake in the area in the year 2017 was a similar M 5.4

on January 22, 2017. Forecast 111197 had expected this earthquake was likely in early October.

 

O: 30SEP2017 06:34:35  37.2S  179.1E Mw=5.0  EMSC   OFF E. COAST OF N. ISLAND, N.Z

O: 30SEP2017 06:34:33  37.1S  179.1E ML=5.4  GEONET Felt with weak intensity

O: 30SEP2017 06:34:36  37.1S  178.8E mw=5.0  ANSS   Opotiki New Zealand

P:  2OCT2017 111197    37.0S  177.0E 3.0-4.4 AABAA  North Island, N.Z.         

 

Moderate aftershocks continued in Chiapas and Oaxaca, Mexico today. The strongest of these was M 4.9-5.0 and was probably lightly felt in Chiapas. This is typical aftershock activity in the region. Forecast 110686 had expected this activity to continue at this time.

 

O: 29SEP2017 20:30:58  14.8N   94.3W mb=4.7  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 29SEP2017 15:30:43  14.9N   93.3W ML=4.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 29SEP2017 10:55:08  14.9N   94.2W ML=4.0  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 29SEP2017 08:46:48  15.0N   94.0W mb=4.4  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 30SEP2017 06:22:40  15.0N   94.3W ML=4.3  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 29SEP2017 11:45:20  15.2N   94.0W mb=4.5  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 29SEP2017 21:50:50  15.2N   94.2W mb=4.9  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 29SEP2017 10:41:51  15.2N   94.8W ML=4.0  EMSC   OFF COAST OF OAXACA, MEXICO

O: 30SEP2017 05:38:46  15.3N   94.5W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 29SEP2017 13:12:01  15.7N   95.2W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 29SEP2017 15:23:54  15.8N   94.7W mb=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 29SEP2017 21:00:01  15.8N   95.1W ML=4.8  EMSC   OFFSHORE OAXACA, MEXICO

O: 30SEP2017 01:28:09  16.0N   95.2W ML=4.6  EMSC   OFFSHORE OAXACA, MEXICO

O: 29SEP2017 21:15:03  16.1N   95.1W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 29SEP2017 08:58:24  16.1N   95.4W ML=4.0  EMSC   OAXACA, MEXICO

O: 29SEP2017 19:22:27  16.2N   94.9W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 30SEP2017 05:42:59  16.4N   95.1W ML=4.0  EMSC   OAXACA, MEXICO

O: 30SEP2017 00:29:39  16.5N   95.2W ML=4.0  EMSC   OAXACA, MEXICO

O: 29SEP2017 15:02:35  16.5N   95.6W ML=4.0  EMSC   OAXACA, MEXICO

O: 29SEP2017 19:52:45  16.6N   95.1W ML=4.4  EMSC   OAXACA, MEXICO

O: 29SEP2017 04:33:15  14.9N   94.1W mb=5.0  ANSS   Tres Picos Mexico            

P: 25SEP2017 110686    14.0N   94.0W 3.5-5.5 BAAAA  Chiapas, Mexico            

P: 30SEP2017 110686    14.0N   93.0W 3.5-5.4 AAAAA  Chiapas, Mexico            

 

The most unusual earthquake in the U.S. or Canada today was an M 3.2 in northern New Mexico. NEIC reported this earthquake was felt in New Mexico with intensity II-III in Rociada, Mora, Cleveland and Albuquerque, New Mexico. The last event within about 100 km of this epicenter of M>=3.2 in New Mexico occurred on October 17, 2011 with M 3.5. Two other events have hit in this area with M>=3.2 in the past 25 years - an M 3.2 on December 18, 2010 and an M 3.8 on July 4, 1995.  Forecast 110746 expected this event in this region around September 28.

 

O: 29SEP2017 11:35:53  35.9N  105.4W ML=3.2  EMSC   NEW MEXICO                   

P: 28SEP2017 110746    36.9N  105.1W 2.0-4.0 AAAAA  Colorado area              

 

The strongest seismicity in the U.S. or Canada today continued in the Aleutian Island and included an M 4.0 in the Fox Islands. This is probably a regional aftershock of the M 5.0 which hit the area and was reported in this summary in the previous issue. Forecast 110841 had expected this activity was likely within about 50 km of this epicenter around September 30.

 

O: 29SEP2017 10:40:30  51.6N  168.1W mb=4.0  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

P: 30SEP2017 110841    51.9N  169.2W 3.5-5.1 AAAAA  Fox Islands, Aleutians     

 

MODERATE AFTERSHOCK IN CHIAPAS, MEXICO

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 28, 2017

 

The strongest earthquake today was an M 5.6 in the Chiapas/Oaxaca, Mexico aftershock zone of the September 8, 2017. This occurred after several days of events of M<4.5 and may have been promoted by the strong geomagnetic storm currently in progress. Other earthquakes in the aftershock sequence followed the general pattern observed over the past days. Areas to the west of this in Guerrero, Mexico were also showing increased seismicity today. Some, or all of this may have been promoted by the current strong geomagnetic storm.

 

O: 28SEP2017 11:39:45  14.8N   94.2W ML=4.2  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 29SEP2017 01:45:39  15.1N   93.6W ML=4.3  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 28SEP2017 18:17:25  15.1N   94.3W ML=4.2  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 28SEP2017 09:50:31  15.2N   94.6W ML=4.0  EMSC   OFF COAST OF OAXACA, MEXICO

O: 28SEP2017 16:55:22  15.2N   94.6W ML=4.1  EMSC   OFF COAST OF OAXACA, MEXICO

O: 28SEP2017 20:23:09  15.3N   93.8W ML=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 28SEP2017 12:26:41  15.3N   93.9W ML=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 28SEP2017 08:49:35  15.4N   94.5W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 28SEP2017 11:02:48  15.4N   94.9W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 28SEP2017 21:25:27  15.8N   94.9W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 29SEP2017 02:08:18  15.9N   95.2W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 28SEP2017 21:31:24  16.5N   95.1W ML=4.5  EMSC   OAXACA, MEXICO

O: 28SEP2017 09:57:48  16.5N   95.2W ML=4.1  EMSC   OAXACA, MEXICO

O: 29SEP2017 02:16:05  16.5N   95.2W ML=4.3  EMSC   OAXACA, MEXICO

O: 28SEP2017 07:27:14  16.5N   95.2W ML=4.4  EMSC   OAXACA, MEXICO               

O: 28SEP2017 07:27:14  16.5N   95.2W ML=4.4  EMSC   OAXACA, MEXICO               

O: 29SEP2017 04:00:24  15.0N   94.0W mb=5.6  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 29SEP2017 04:00:22  14.9N   94.0W mb=5.6  ANSS   Tres Picos Mexico

P: 30SEP2017 110687    17.0N   94.0W 3.5-5.6 AAAAA  Chiapas, Mexico            

 

The M 5.6 in Mexico was followed 18 minutes later by an M 3.0 near Stroud, Oklahoma. This event was reported felt with maximum intensity III in Stroud, Cushing and possibly Sapulpa, Oklahoma. At 21 degrees from the Mexican quake, it may have been promoted by ScS phases from that event which arrived in this epicentral area of Oklahoma about 16 minutes (2 minutes before) the subsequent event in Oklahoma.

 

The strongest earthquake today in the U.S. or Canada outside Alaska was an M 4.4 in the area of Vancouver Island, British Columbia as reported by Earthquakes Canada. The last event of M>=4.4 within about 100 km of this epicenter was an

M 4.8 on June 10, 2017.  Forecast 110838 expected this unfelt event within about 50 km of the epicenter was likely around September 28.

 

O: 28SEP2017 07:48:02  50.6N  130.5W ML=4.4  NRCA  218 km W   of Pt. Hardy       

O: 28SEP2017 05:46:33  51.1N  130.7W ML=3.0  NRCA  216 km WSW of Bella Bella     

P: 28SEP2017 110838    50.4N  130.2W 3.0-4.9 AAAAA  British Colombia           

 

Three moderate earthquakes also occurred in the Aleutian of Alaska today. Two of these occurred in the area south of the Fox Islands near Yunaska Island with  M 4.5 and 5.0. This is the strongest seismicity in this region within about 100 km

of this epicenter since August 9, 2017 (M 5.3) and prior to that an M 5.2 on May 19, 2017. Forecast 110831 had expected this area to be active around September 30.

 

 

O: 29SEP2017 01:26:45  52.1N  170.0W mb=4.5  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O: 29SEP2017 01:26:45  52.0N  170.0W mb=4.5  ANSS   Yunaska Island Alaska

O: 29SEP2017 01:22:41  52.3N  170.2W mb=4.9  ANSS   Yunaska Island Alaska

O: 29SEP2017 01:22:40  52.4N  169.9W ML=5.0  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

P: 30SEP2017 110841    51.9N  169.2W 3.5-5.1 AAAAA  Fox Islands, Aleutians     

 

The other unfelt event was an M 4.4 in the central Andreanof Islands, an area which has been relatively quiet in recent months. The last earthquake of M>=4.4 within about 100 km of this epicenter was an M 4.6 on August 13, 2017 and prior to that on August 1, 2017 with M 5.2.  Forecast 110836 had expected this event was likely around September 25 within about 100 km of this epicenter. It is likely that this and the activity in the Fox Islands was promoted by the strong geomagnetic storm in progress. It occurred within about 20 minutes of local solar noon, a prime time for geomagnetic  triggering.

 

O: 28SEP2017 23:16:42  51.4N  175.6W ML=4.4  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P: 25SEP2017 110836    51.2N  174.4W 3.5-5.3 BAAAA  Andreanoff Isls, Aleutians 

 

GEOMAGNETIC STORM MAY PROMOTE ADDITIONAL EQUATORIAL SEISMICITY

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 27, 2017

 

The geomagnetic field was at stormy conditions today.  The AP level was 37. High latitude geomagnetic field also saw major storm conditions with AP at 47. This is the strongest geomagnetic storm since AP reached 96 on September 8 - a condition which was accompanied by the great M 8.2 quake in Chiapas, Mexico. Some seismicity near the equator and poles may increase in the next day but major increases are more likely after the first of October, about 4-5 days after the current storm becomes inactive.

 

Seismicity in the aftershocks zone of the M 8.2 in Chiapas and succeeding events in Oaxaca and Guerrero and Puebla continued today. The largest of these were of M 4.2-4.3 and no events of M>=5 occurred today.

 

O: 27SEP2017 11:55:31  15.2N   94.5W ML=4.3  EMSC   OFF COAST OF OAXACA, MEXICO

O: 27SEP2017 12:22:53  15.2N   94.7W ML=4.3  EMSC   OFF COAST OF OAXACA, MEXICO

O: 27SEP2017 15:30:24  15.4N   94.7W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 28SEP2017 04:56:13  15.4N   94.8W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 28SEP2017 05:01:13  15.5N   95.1W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 27SEP2017 11:25:10  15.6N   95.0W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 27SEP2017 14:31:44  15.7N   94.5W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 27SEP2017 21:09:09  15.8N   95.2W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 27SEP2017 23:30:16  16.1N   95.1W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 27SEP2017 20:35:26  16.3N   95.0W ML=4.0  EMSC   OAXACA, MEXICO

O: 27SEP2017 09:37:49  16.5N   95.1W ML=4.1  EMSC   OAXACA, MEXICO

O: 28SEP2017 07:27:14  16.5N   95.2W ML=4.4  EMSC   OAXACA, MEXICO

O: 28SEP2017 05:08:41  16.7N   94.9W mb=4.2  EMSC   OAXACA, MEXICO                

P: 30SEP2017 110687    17.0N   94.0W 3.5-5.6 AAAAA  Chiapas, Mexico            

 

The strongest earthquake in the U.S. or Canada today was an M 4.0 in the area of the Fox Islands south of the Aleutians. This is a remote area and this event was not reported felt in the area. The last earthquake with M>=4 within

about 100 km of this epicenter was an M 5.9 on May 24, 2017. Forecast 110841 had expected this event within about 50 km of the epicenter was likely around September 24.

 

O: 27SEP2017 17:14:09  52.9N  165.5W ML=4.0  EMSC   SOUTH OF ALEUTIAN ISLANDS    

P: 24SEP2017 110841    52.3N  165.7W 3.5-4.9 BAAAA  Fox Islands, Aleutians     

 

The strongest activity in the world today were a series of quakes in the region of Japan of M 4.8-5.4. The strongest of these was an M 4.5 (EMS) - 5.4 (CWB) off eastern Honshu in the area of the southern Ryukyu Islands.  CWB reported this earthquake was felt with intensity I in Hualien and Taitung Counties, Taiwan. Forecast 110724 had expected this event within about 50 km around September 27. This event is at the third node (120 degrees) from the Chiapas M 8.2 event and was probably promoted by energy from that source.

 

O: 27SEP2017 21:56:38  25.1N  123.4E mb=4.5  EMSC   NORTHEAST OF TAIWAN          

O: 27SEP2017 21:56:39  24.7N  123.6E ML=5.4  TAI    Hualien, Taiwan              

P: 27SEP2017 110724    25.0N  123.0E 4.0-5.6 AAAAA  Ryukyu Islands             

 

Earthquakes in the Bonin Islands and off the east coast of Honshu, Japan of M 4.7-4.8 continued the activity in the region at 103 degrees from the M 8.2 Chiapas  earthquake of September 8. These area probably by concentrated seismic energy

from that event and the continuing aftershocks. These events were not reported felt but were probably lightly felt in the epicentral areas. Forecasts 110713 had expected the M 4.7 and M 4.8 in the Bonin Islands was likely at the end of

September while the M 4.8 off eastern Honshu was expected within about 50 km of that epicenter around September 27 in forecast 110762.

 

O: 27SEP2017 21:47:40  28.6N  140.7E mb=4.7  EMSC   BONIN ISLANDS, JAPAN REGION  

O: 27SEP2017 21:10:37  28.8N  140.6E mb=4.8  EMSC   BONIN ISLANDS, JAPAN REGION  

P: 30SEP2017 110713    29.0N  142.0E 4.0-5.5 AAAAA  Bonin Islands              

 

O: 28SEP2017 07:11:29  37.4N  141.5E mb=4.8  EMSC   NEAR EAST COAST OF HONSHU, JAP

P: 27SEP2017 110762    37.0N  141.0E 4.0-5.8 AAAAA  Off East Coast Honshu      

 

STRONG QUAKE IN NORTHERN HONSHU, JAPAN AT 103 DEGREES FROM CHIAPAS, MEXICO

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 26, 2017

 

The strongest earthquake in the world today was a strong M 5.9 in northern Honshu, Japan. NEIC reported it was felt with maximum intensity VI in Kamaishi, Iwate and IV in Misawa, Aomori. Also felt with intensity II-III within about 250 km of this epicenter at Morioka, Aomori, Hanamaki, Kizukuri, Shichigahama, Sendai, Tsukuba, Naka, Narashino, Tokyo and Higshimurayama, Japan. This earthquake occurred at 103-104 degrees from the M 8.2 of September 8, 2017 in Chiapas, Mexico. Seismic energy from large earthquakes is reflected and refracted off core-mantle boundaries and returns to the surface at this distance. As seismicity is often seen to increase dramatically at this distance from and after large earthquakes, it appears that triggering of zonal seismicity is occurring. The relation between Japan and Mexico in this regard has been previously emphasized in this report. As an example most recently on September 21 as follows:

 

 

"Far Distance triggering from Chiapas today apparently included an M 4.6 in the Sea of Japan at 103 degrees from the Chiapas epicenter. Further activity in the Hokkaido area of M>=5 may be expected in the next several days." (September 10, 2017)

 

"The distance from the great Mexican earthquake of September 8 to this epicenter is 103 degrees, supporting the hypothesis that it was a triggered event." (September 21, 2017)

 

Today's event is the strongest within about 200 km of this epicenter in more than a year. An M 6.0 occurred about 100 km east of this epicenter on August 20, 2016 and prior to that an M 6.7 hit north of this on January 14, 2016. Forecast 110796 expected today's event in this area was likely around September 26. This epicenter is 104 degrees from the M 8.2 in Mexico. Other events at this distance today from Mexico include an M 4.6 felt in central Vanuatu.

 

O: 26SEP2017 20:22:13  40.3N  142.4E Mw=5.9  EMSC   NEAR EAST COAST OF HONSHU, JAP

O: 26SEP2017 20:22:11  40.3N  142.4E mw=5.9  ANSS   ESE of Hachinohe Japan

P: 26SEP2017 110796    40.0N  144.0E 3.5-5.7 AAAAA  Hokkaido, Japan            

 

An M 2.1 in Central California south of San Francisco near Aromas, California was recorded 17 minutes after the M 5.9 in Honshu, Japan. This event is at the fifth node (72 degrees) from Japan. Reflected waves from Japan (PPPP and PcS) were at the point of rupture in California when this M 2.1 occurred. Hair triggering of this type suggests the triggered area, in this case central California, is under considerable stress which could lead to a larger earthquake in a short time/distance from today's epicenter near Aromas, California.

 

O: 26SEP2017 20:39:01  36.9N  121.6W MD=2.1  EMSC   CENTRAL CALIFORNIA           

P: 27SEP2017 110740    37.3N  121.6W 2.5-4.4 AAAAA  Central California         

 

A light series of earthquakes is occurring in the Ojai region of western Los Angeles, California. The largest to date is an M 2.6. NEIC reported this was felt with maximum intensity IV in Santa Paula, California and II-III in Ojai, Ventura, Carpinteria, Oak View, Camarillo, and Malibu, California. This should be watched as it is occurring in a region where a moderate to strong earthquake could occur shortly as part of the 22-23 year cycle of large events in the area. The last earthquake within about 50 km of these epicenters occurred on August 24, 2017 while the last of larger magnitude was an M 3.2 on May 6, 2017. Forecast 110774 had expected an event in this region around September 26.

 

 

O: 27SEP2017 06:24:12  34.4N  119.4W ML=2.1  EMSC   SOUTHERN CALIFORNIA          

O: 27SEP2017 05:30:30  34.4N  119.4W ML=2.2  EMSC   SOUTHERN CALIFORNIA          

O: 27SEP2017 04:48:35  34.4N  119.4W ML=2.5  EMSC   SOUTHERN CALIFORNIA          

P: 26SEP2017 110774    34.7N  119.0W 2.5-4.4 AAAAA  So. California             

 

Moderate aftershocks in Chiapas and Oaxaca, Mexico continued today with the largest of M 4.5. These were not strongly felt and no additional damage was reported. A light aftershock of the Puebla earthquake of September 19 (M 7.1) was also recorded today. This event of M 3.0 is one of the strongest aftershocks in that region since the mainshock occurred. Forecast 110722 had expected this aftershocks was likely within about 15 km of the epicenter around September 17.

 

O: 26SEP2017 10:56:52  20.1N   99.1W ML=3.0  UNAM  l SURESTE de PROGRESO, HGO *: 2

P: 27SEP2017 110722    20.0N   99.0W 3.0-4.6 AAAAA  Northern Mexico            

 

Forecasts 110686 and 110687 had expected the aftershock sequence to linger at this time.

 

O: 26SEP2017 10:25:58  15.2N   94.6W ML=4.1  EMSC   OFF COAST OF OAXACA, MEXICO

O: 26SEP2017 20:39:53  15.4N   94.8W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 26SEP2017 16:07:48  15.7N   94.5W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 26SEP2017 13:42:36  15.7N   95.0W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 26SEP2017 07:07:58  16.4N   95.1W ML=4.4  EMSC   OAXACA, MEXICO

O: 26SEP2017 10:55:07  16.4N   95.2W ML=4.0  EMSC   OAXACA, MEXICO

O: 26SEP2017 15:12:03  16.4N   95.2W ML=4.0  EMSC   OAXACA, MEXICO

O: 26SEP2017 07:40:18  16.4N   95.2W ML=4.1  EMSC   OAXACA, MEXICO

O: 26SEP2017 22:02:01  16.4N   95.2W ML=4.1  EMSC   OAXACA, MEXICO

O: 27SEP2017 06:14:39  16.5N   95.1W ML=4.0  EMSC   OAXACA, MEXICO

O: 26SEP2017 18:53:44  16.5N   95.2W ML=4.8  EMSC   OAXACA, MEXICO

O: 26SEP2017 08:31:46  16.6N   95.1W ML=4.2  EMSC   OAXACA, MEXICO               

P: 24SEP2017 110687    16.0N   95.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

P: 25SEP2017 110686    14.0N   94.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

 

It was a quiet day in U.S. and Canadian seismicity. The strongest events were an M 3.4 in western Nevada; an 3.3 in Hawaii and an M 3.0 off the coast of northern California but these (with the Nevada exception) were not reported felt in their respective epicentral areas. The most unusual felt earthquake in the U.S. or Canada today was a mere M 2.9 as no quakes of M>=3 occurred in Alaska, California or the central Plains. This earthquake occurred in the Yellowstone National Park area of Wyoming. The only earthquake in the Yellowstone area in the past month of greater magnitude

was an M 3.1 on September 17. Forecast 110832 had expected today's event within about 50 km of this epicenter around September 25.

 

NEIC reported this earthquake of M 2.9 in Wyoming was felt with intensity II-III in the area(s) of Yellowstone National Park, Wyoming.

 

O: 26SEP2017 06:31:10  44.8N  110.7W ML=2.9  EMSC   YELLOWSTONE NAT. PARK, WYOMING

P: 25SEP2017 110832    44.2N  110.3W 2.0-4.0 AAAAA  Yellowstone/Wyoming        

 

O: 26SEP2017 21:51:23  40.3N  127.0W ML=3.0  EMSC   OFF COAST OF NORTHERN CALIFORN

P: 29SEP2017 110814    40.3N  127.2W 2.5-4.6 BAAAA  Off Coast of No. Calif     

 

O: 26SEP2017 18:21:37  19.3N  155.2W ML=3.3  EMSC   ISLAND OF HAWAII, HAWAII     

P: 28SEP2017 110693    19.9N  155.8W 3.0-4.4 AAAAA  Hawaii                     

 

NEIC reported the earthquake of M 3.4 in Nevada was felt with intensity II-III in the area(s) of Hawthorne, Nevada.

 

O: 26SEP2017 08:40:06  38.4N  118.9W ML=3.4  EMSC   NEVADA                       

P: 25SEP2017 110737    38.4N  118.2W 2.5-4.6 AAAAA  California/Nevada area     

 

An event of M 4.8 did shake the U.S. Possession of Guam today. The epicenter was north of Guam but much of Guam reported tremor from this event. This may be  an aftershock of the M 5.7 which hit the area on September 2. Forecasts 110433

and 110708 expected this in mid- to late-September closer to Guam. Guam is located at 145 degrees from the great Mexican quake and was probably promoted by energy concentrated at that distance following reflections off core boundaries to this distance on the surface. NEIC reported this earthquake of M 4.8 in the Mariana Islands was felt with intensity II-III in the area(s) of Guam at Yigo, Tamuning, Mangilao, Hagatna, Santa Rita and Merizo.

 

O: 26SEP2017 23:44:12  14.1N  145.1E mb=4.8  EMSC   ROTA REGION, N. MARIANA ISLAND

P: 18SEP2017 110433    13.0N  144.0E 4.0-5.6 CBAAA  So. Marianas/Guam          

P: 22SEP2017 110708    13.0N  143.0E 4.0-5.4 BBBAA  So. Marianas/Guam          

 

STRONG QUAKES IN SOUTH PACIFIC BETRAY MEXICAN TRIGGERING

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 25, 2017

 

A pair of strong earthquakes in the South Pacific today showed signs of being promoted by energy from the series of earthquakes in Mexico this past month. The strongest of these Pacific Island earthquakes was an M 6.4 south of the Fiji Islands, but an earlier earthquake in the region of M 6.0 also hit the region of New Britain. The M 6.4 in Fiji was a right angle quake to the M 8.2 in Chiapas of September 8 - it (and two events in Tonga of M 5.1 and 4.5)  occurred at exactly 90.0 degrees from that epicenter while the New  Britain earthquake of M 6.0, at 108 degrees from the M 7.1 Puebla earthquake was likely promoted by concentrated energies from that event.

 

The earthquake south of Fiji occurred at an intermediate depth near 100 km  and was not reported felt in this remote area. The last earthquake with M 6.4 within about 150 km of this epicenter occurred as an M 7.4 on May  23, 2013. An M 6.9 occurred about 250 km northwest of today's epicenter on February 24, 2017.

Forecast 110905 expected this event within about 50 km of the epicenter was likely around September 29.

 

O: 26SEP2017 04:20:00  23.6S  176.9W Mw=6.4  EMSC   SOUTH OF FIJI ISLANDS        

P: 29SEP2017 110905    24.0S  177.0W 4.0-5.4 BAAAA  Tonga Islands              

 

Fiji was not the only active area of the South Pacific today. In addition to the M 6.0 in New Britain three moderate earthquakes were felt up and down the Vanuatu Islands and a moderate earthquake was felt in North Island, New Zealand (M 4.8). Details can be found under the regional listings below. The M 6.0 in New Britain was the strongest within about 150 km of that epicenter since an M 6.3 on December 17, 2016 and prior to that an M 6.1 on December 10, 2016 about 200 km west of today's epicenter. An M 7.9 hit near this epicenter on  December 17, 2016. Forecast 110667 had expected this event was possible within about 100 km of the epicenter around September 28. Much of this activity including the Vanuatu events of M 4.6 and 4.6 occurred at 101-104 degrees from the great M 8.2 in Chiapas, Mexico of September 8. It was probably promoted by concentrated seismic energy from that event and aftershocks. Other events at this distance

from Mexico today occurred in southern Honshu, Japan near Tokyo (M 4.2).

 

O: 25SEP2017 20:29:24   6.3S  152.8E Mw=6.0  EMSC   NEW BRITAIN REGION, P.N.G.   

P: 28SEP2017 110667     7.0S  153.0E 4.0-5.5 BAAAA  New Britain                

 

Aftershocks continued in the aftershock sequence of the M 8.2 in Chiapas and the M 6.1 in Oaxaca, Mexico today. There were no events of M>=4.7  today for the first time since these sequences began. No major additional damage was reported in the area. The Mexico City quake is now reported to have killed at least 315 people. Forecast 110686 and others had expected this activity at this time.

 

O: 25SEP2017 07:50:40  14.9N   93.8W mb=4.4  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 25SEP2017 06:27:06  15.1N   93.7W ML=4.3  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 25SEP2017 14:30:35  15.1N   94.6W ML=4.6  EMSC   OFF COAST OF OAXACA, MEXICO

O: 25SEP2017 16:29:31  15.2N   94.7W ML=4.5  EMSC   OFF COAST OF OAXACA, MEXICO

O: 25SEP2017 09:36:53  15.4N   94.7W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 25SEP2017 09:39:21  15.4N   94.7W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 25SEP2017 17:54:34  15.4N   94.8W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 25SEP2017 14:09:31  15.5N   94.2W mb=4.4  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 25SEP2017 07:23:45  15.5N   94.2W mb=4.5  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 25SEP2017 04:29:14  15.7N   94.6W mb=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 25SEP2017 23:52:24  15.7N   95.2W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 25SEP2017 19:08:04  16.0N   95.1W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 25SEP2017 03:47:16  16.3N   95.1W ML=4.1  EMSC   OAXACA, MEXICO

O: 25SEP2017 15:05:25  16.3N   95.1W ML=4.2  EMSC   OAXACA, MEXICO

O: 25SEP2017 18:35:45  16.4N   95.0W ML=4.2  EMSC   OAXACA, MEXICO

O: 25SEP2017 10:42:43  16.4N   95.0W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 25SEP2017 17:09:32  16.4N   95.1W ML=4.1  EMSC   OAXACA, MEXICO

O: 25SEP2017 17:09:32  16.4N   95.1W ML=4.1  EMSC   OAXACA, MEXICO

O: 25SEP2017 05:07:17  16.4N   95.1W ML=4.2  EMSC   OAXACA, MEXICO

O: 25SEP2017 05:55:12  16.4N   95.1W ML=4.2  EMSC   OAXACA, MEXICO

O: 25SEP2017 10:29:25  16.4N   95.1W ML=4.3  EMSC   OAXACA, MEXICO

O: 25SEP2017 17:46:00  16.4N   95.2W ML=4.3  EMSC   OAXACA, MEXICO

O: 25SEP2017 19:20:55  16.6N   95.0W ML=4.3  EMSC   OAXACA, MEXICO

O: 26SEP2017 05:33:20  14.9N   94.2W mb=4.6  EMSC   OFF COAST OF CHIAPAS, MEXICO 

P: 25SEP2017 110686    14.0N   94.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

The strongest earthquake in the U.S. or Canada was an M 3.6 in the aftershock sequence of the M 5.8 of July 6. Only one other aftershock has reached M 3.6 in this area since early July - an M 3.6 on August 20, 2017. Today's event was probably felt lightly in the epicenter area. Forecast 110805 had expected regional activity in this aftershock zone was likely around September 29.

 

O: 25SEP2017 08:44:42  46.9N  112.5W ML=3.6  EMSC   WESTERN MONTANA              

P: 29SEP2017 110805    45.7N  112.1W 2.0-4.1 BBAAA  Montana/Idaho              

 

POSSIBLE IMMINENT ERUPTION OF AGUNG VOLCANO, BALI, BRINGS EVACUATIONS

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 24, 2017

 

An imminent eruption of Agung Volcano in Bali, Indonesia has caused the evacuation of more than 50,000 from areas surrounding the volcano. The last eruption of Agung was in 1963. That eruption killed more than 1000 people but evacuation procedures were not as sophisticated in that event 54 years ago. More than 1000 earthquakes have been recorded in the past several days in the region including several of moderate magnitude. Agung is Bali's largest volcano. Agung began to show signs of eruptive activity after the M 7.1 which struck central Mexico on September 19. This volcano is at 145 degrees from the Mexican epicenter. Seismic waves reflect and refract off core boundaries and return to the surface at this distance in concentrated form. It is likely that this eruption was promoted by these waves from Mexico. Another volcanic eruption triggered by waves from the earthquake in Puebla, Mexico was Popocatepetl in Central Mexico which continues to erupt. Forecast 110400 had expected seismicity in this area in late September.

 

O: 24SEP2017 10:48:59   8.3S  113.0E ML=3.1  EMSC   JAVA, INDONESIA              

P: 19SEP2017 110400     6.0S  113.0E 4.0-5.4 BCAAA  So. of Bali                

 

The largest earthquake in the world today was an M 5.7 aftershock of the great

M 8.2 in Chiapas of September 8. NEIC reported today's earthquake was felt with intensity II-III in Chiapas at Tuxtla Gutierrez, San Cristobal de las Casas, Comitan, Ocozocoautla, in Quetzaltnango and Santa Catarina Pinula, Guatemala, and in other areas of eastern Mexico. Forecast 110686 and 110687 had expected this aftershock activity.

 

O: 24SEP2017 12:41:47  15.1N   94.2W ML=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 25SEP2017 02:26:25  15.1N   94.2W ML=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 24SEP2017 10:48:00  15.3N   94.3W ML=4.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 24SEP2017 10:06:10  15.4N   94.1W Mw=5.7  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 24SEP2017 22:35:55  15.4N   94.5W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 24SEP2017 15:52:06  15.5N   95.1W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 24SEP2017 23:29:30  15.7N   94.3W Mw=4.7  EMSC   OFFSHORE OAXACA, MEXICO

O: 24SEP2017 11:50:22  15.9N   94.4W mb=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 25SEP2017 00:56:50  15.9N   94.7W mb=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 24SEP2017 10:53:12  16.0N   94.6W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 24SEP2017 11:50:16  15.3N   94.9W ML=4.5  UNAM  al SURESTE de SALINA CRUZ, OAX

P: 22SEP2017 110686    15.0N   94.0W 3.5-5.6 AAAAA  Chiapas, Mexico            

 

O: 24SEP2017 09:26:52  16.4N   95.0W ML=4.3  EMSC   OAXACA, MEXICO

O: 24SEP2017 12:11:09  16.4N   95.2W ML=4.0  EMSC   OAXACA, MEXICO

O: 24SEP2017 19:12:47  16.4N   95.2W ML=4.2  EMSC   OAXACA, MEXICO

O: 24SEP2017 07:59:43  16.5N   94.9W mb=4.0  EMSC   OAXACA, MEXICO

O: 24SEP2017 15:02:50  16.5N   95.0W mb=4.2  EMSC   OAXACA, MEXICO

O: 24SEP2017 15:59:16  16.5N   95.1W ML=4.0  EMSC   OAXACA, MEXICO

O: 24SEP2017 16:53:02  16.5N   95.2W ML=4.1  EMSC   OAXACA, MEXICO

O: 24SEP2017 18:13:21  16.6N   95.3W ML=4.2  EMSC   OAXACA, MEXICO

O: 24SEP2017 18:13:21  16.6N   95.3W ML=4.2  UNAM  l NOROESTE de CD IXTEPEC, OAX *

P: 24SEP2017 110687    16.0N   95.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

O: 24SEP2017 07:13:34  15.6N   96.4W ML=4.0  UNAM  l SURESTE de S PEDRO POCHUTLA,

P: 22SEP2017 110704    15.0N   96.0W 3.5-5.5 AAAAA  Oaxaca, Mexico             

 

An earthquake of M 4.9 occurred today in the Dodecanese Islands of Greece and Turkey today. NEIC reported maximum intensity IV in Kos, Dodecanese Islands and in Bodrum, Mugla, Turkey. Lesser shaking of II-III was felt in Greece at Pilion, Antmakhia, Kardamaina, Panormos, and in Milas, Turkey among other communities in western Turkey. This epicenter is at 103-104 degrees from the great M 8.2 earthquake in Chiapas, Mexico of September 8, 2017 and was probably promoted by concentrated energy from that event. Forecast 110731 had expected this was likely around September 24.

 

O: 24SEP2017 16:57:16  36.9N   27.3E mb=4.9  ANSS   N of Kos Greece

O: 24SEP2017 16:57:17  36.9N   27.3E Mw=4.5  EMSC   DODECANESE IS.-TURKEY BORDER R

P: 24SEP2017 110731    38.0N   26.0E 3.0-4.6 ABAAA  Aegean Sea                 

 

STRONG EARTHQUAKE FELT IN OAXACA, MEXICO

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 23, 2017

 

A strong earthquake of M 6.1 in Oaxaca, Mexico continued the elevated seismicity in that area today. NEIC reported it was felt with maximum intensity VII in Juchitan, Oaxaca and IV in Xadani, Atzompa, Oaxaca; Tuxtla Guiterrez, Chiapas, Cordoba, Veracruz; Atizapan, Metepec, Cuautitlan Izcalli, Tenancingo, Zacamulpa, Coatepec, San Pablo de las Salinas, Tlalnepantla, Naucalpan, Buenavista, Mexico City, Santa Catarina Pinula and Mixco Guatemala; Nezahualcoyotl, Iguala,  Los Reyes, Cuernavaca, Morelos, Magdalena Tequisistlan, Mitla, Las Chapas, and Coatzacoalcos, Veracrus, Ocozocoautla, Huatulco, Tectacpan, Oaxaca, Sant Lucis del Camino and in general within about 100 km of the epicenter.

This is a regional aftershock of the M 8.2 of September 8 south of Chiapas, Mexico. It was widely felt because the epicenter was not offshore but under land. This earthquake claimed five deaths bringing the toll in the series of earthquakes in Mexico this month to well over 400 with an estimated cost to Mexico of more than $8 billion U.S. Dollars. These include the five killed today, 95 in the M 8.2 on September 8 and 305 in the Puebla quake which shook Mexico City on September 19. In addition to the earthquakes, the eruption of Popocatepetl south of Mexico City continued today and send ash clouds into the sky.  The strongest aftershock of the M 8.2 in Chiapas was an M 5.8. NEIC reported it was felt with intensity IV in Oaxaca and Chiapas at Juchitan, Tuxtla Gutierrez, Xadani, and II-III in Mexico City, Atzompa, Oaxaca, Puerto Escondido, Coyotepec, Quetzaltenango, Guatemala, Villahermosa, Tabasco, Mexico and An aftershock of M 4.9 was felt with intensity II-III in Matias Romero, Mitla, Oaxaca and in Veracruz at Cordoba and in Mexico City. Also felt with light intensity in San Pedro Sacatepequez, San Marcos, Guatemala. An immediate aftershock of M 4.8 was felt with intensity II in Mitla, Oaxaca, Fortin, Veracruz and Mexico City. Smaller aftershocks were also generally felt in Tuxtla Gutierrez, Chiapas, Mexico with light intensity. Forecasts 110686 and 110687 had expected this activity was likely around September 24-25.

 

O: 23SEP2017 08:35:12  14.7N   93.3W ML=4.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 23SEP2017 07:29:21  14.8N   93.2W ML=4.3  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 23SEP2017 11:16:06  14.9N   94.3W ML=4.0  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 23SEP2017 08:42:08  15.0N   93.6W ML=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 23SEP2017 08:30:53  15.0N   94.3W ML=4.1  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 23SEP2017 08:27:40  15.1N   93.8W ML=4.1  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 23SEP2017 07:12:51  15.2N   94.6W ML=4.3  EMSC   OFF COAST OF OAXACA, MEXICO

O: 23SEP2017 10:55:04  15.3N   94.6W ML=4.1  EMSC   OFF COAST OF OAXACA, MEXICO

O: 23SEP2017 09:43:43  15.3N   94.7W ML=4.2  EMSC   OFF COAST OF OAXACA, MEXICO

P: 24SEP2017 110687    16.0N   95.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

P: 25SEP2017 110686    14.0N   94.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

O: 23SEP2017 04:56:37  15.7N   95.2W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 23SEP2017 03:34:26  15.7N   96.4W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 23SEP2017 07:18:56  15.8N   94.5W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 23SEP2017 20:53:34  16.2N   95.3W ML=4.3  EMSC   OAXACA, MEXICO

O: 23SEP2017 20:36:23  16.3N   95.2W ML=4.6  EMSC   OAXACA, MEXICO

O: 23SEP2017 14:54:04  16.3N   95.3W ML=4.4  EMSC   OAXACA, MEXICO

O: 24SEP2017 00:20:04  16.4N   95.0W ML=4.0  EMSC   OAXACA, MEXICO

O: 23SEP2017 20:01:08  16.4N   95.1W ML=4.2  EMSC   OAXACA, MEXICO

P: 24SEP2017 110687    16.0N   95.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

P: 25SEP2017 110686    14.0N   94.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

O: 24SEP2017 02:03:35  16.6N   94.8W mb=4.2  EMSC   OAXACA, MEXICO

O: 23SEP2017 15:06:34  16.6N   95.0W mb=4.2  EMSC   OAXACA, MEXICO

O: 23SEP2017 14:31:46  16.7N   94.9W mb=4.9  EMSC   OAXACA, MEXICO

O: 23SEP2017 12:53:02  16.7N   95.0W Mw=6.1  EMSC   OAXACA, MEXICO

O: 23SEP2017 12:53:02  16.7N   94.9W mw=6.1  ANSS   Matias Romero Mexico

O: 23SEP2017 23:06:34  16.7N   95.0W mb=4.5  EMSC   OAXACA, MEXICO

O: 23SEP2017 14:18:20  16.7N   95.1W mb=4.4  EMSC   OAXACA, MEXICO

O: 23SEP2017 16:24:53  16.8N   94.7W mb=4.4  EMSC   OAXACA, MEXICO

O: 23SEP2017 14:27:52  16.8N   95.0W mb=4.2  EMSC   OAXACA, MEXICO

O: 23SEP2017 13:24:12  16.8N   95.0W mb=4.8  EMSC   OAXACA, MEXICO

O: 23SEP2017 16:16:28  17.0N   95.1W ML=4.6  EMSC   OAXACA, MEXICO

P: 24SEP2017 110687    16.0N   95.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

P: 25SEP2017 110686    14.0N   94.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

 

An earthquake of M 5.7 was also felt widely today in Northern Mindanao, Philippines. NEIC reported it was felt with maximum intensity IV in Northern Mindanao at Sumpong, Cagayan, Barra, Bugo, and within about 100 km of the epicenter. Lesser shaking of II-III was felt in Talangnan, Central Visayas and in northern Mindanao at Lagonglong, El Salvador, Igpit, Davao, Libertad, Mahayag, Lumbia, Lacson, Valencia and Kibawe, Philippines. PHIVOLCS reported the M 5.4-5.7 was felt with intensity VI in Dalilanga, Bukidnon; V in Cagayan De Oro City; IV in Pangantucan, Kadingilan, Maramag, Damulog, Quezond and Don Carlos Budkidnon; Valencia City; Malaybalay City, Bukidnon; III in Kabacan, North Cotabato; Talakag, Bukidnon; Tagoloan, Misamis Oriental and II in Kidapawan City, Philippines. An aftershocks of M 4.3 was felt with intensity IV in Kalilangan, Bukidnon; III in Pangantucan, Maramag and Valencia City, Bukidnon and II in Cagayan Del Oro City, Philippines. Another aftershock of M 4.0 was felt with intensity III in Wao, Lanao Del Sur, and II in Cagayan de Oro City, Philippines. An event of M 5.1 earlier in the day shook area of Central Luzon including intensity II in Subic and Prinza, Southern Tagalog, Philippines. The last earthquake of M>=5.7 in Mindanao was an M 5.8 on August 5 about 150 km south of today's epicenter. Forecast 110648 had expected today's activity in Mindanao was likely at the end of September.

 

O: 23SEP2017 20:47:05  07.5N  124.6E MS=5.4  PHI  Felt with intensity VI

O: 23SEP2017 21:17:30  07.5N  124.7E MS=4.3  PHI  Felt with intensity IV

O: 24SEP2017 02:39:23  07.7N  124.8E MS=4.0  PHI  Felt with intensity III

O: 23SEP2017 20:47:08   7.8N  124.8E Mw=5.7  EMSC   MINDANAO, PHILIPPINES        

P: 30SEP2017 110648     7.0N  126.0E 4.0-5.7 CAAAA  Central Philippines        

 

The earthquake in Mindoro of M 5.1 had been expected in forecast 110696 in late September within about 100 km of this epicenter.

 

O: 23SEP2017 13:30:33  13.7N  120.8E mb=5.1  EMSC   MINDORO, PHILIPPINES         

P: 28SEP2017 110696    13.0N  121.0E 3.5-5.1 BAAAA  Luzon, Philippines         

 

The strongest earthquakes in the U.S. or Canada today included an M 3.8 in Oklahoma and an aftershock of M 3.8 in Southern Idaho. Aftershocks of this magnitude or larger have been common in the aftershocks sequence of the M 5.3 of September 2 with the last an M 3.7 on September 16. It is a bit surprising, however, how long this aftershock sequence is taking to wind down. Forecast 110552 had expected a moderate aftershock was likely around September 20. Likewise Oklahoma has been active in September with an M 3.9 on September 16. Forecast 110783 had expected this M 3.8 was likely within about 50 km of the epicenter around September 22.

 

NEIC reported these earthquakes of M 2.6 and M 2.7 in southern Idaho were felt with intensity II-III in the area(s) of Soda Springs, Idaho. The strongest quake in the aftershock sequence today was an M 3.8 felt with intensity II-III in Idaho at Montpelier, Soda Springs, Preston, Bancroft, Franklin and Malad City and in Utah at Clarkston and Tremonton.

 

O: 23SEP2017 18:50:01  42.6N  111.4W ML=2.6  EMSC   SOUTHERN IDAHO

O: 23SEP2017 16:35:27  42.6N  111.4W ML=2.7  EMSC   SOUTHERN IDAHO

O: 24SEP2017 05:28:35  42.6N  111.5W ML=3.2  EMSC   SOUTHERN IDAHO

O: 23SEP2017 15:20:00  42.5N  111.4W Mw=3.8  EMSC   SOUTHERN IDAHO               

P: 20SEP2017 110552    43.0N  111.5W 2.0-4.1 BAAAA  Yellowstone/Wyoming        

 

NEIC reported the earthquake of M 3.8 in Oklahoma was felt with intensity V in Perry, Oklahoma; IV in Red Rock and II-III in the area(s) of Stillwater, Glencoe, Pawnee, Ponca City, Perkins, Edmond, Skiatook, Sapulpa, Tulsa, Kiefer, Oklahoma City, Jenks, Broken Arrow, and in Wichita and Andover, Kansas.

 

O: 24SEP2017 01:11:37  36.4N   97.1W Mw=3.8  EMSC   OKLAHOMA                     

P: 22SEP2017 110783    37.0N   97.0W 2.0-3.9 AAAAA  Southern Plains            

 

A more unusual earthquake occurred in Utah today with M 3.4. While an M 4.3 hit about 250 km southeast of this epicenter on September 8, no other events of M>=3.4 have been recorded in Utah during the year 2017. Forecast 110787 had expected Utah would be active towards the end of September. There was no reported damage with today's Utah earthquake.

 

O: 24SEP2017 04:38:44  38.6N  112.1W ML=3.4  EMSC   UTAH                         

O: 24SEP2017 04:38:44  38.6N  112.1W ml=3.4  ANSS   ESE of Monroe Utah

P: 30SEP2017 110787    37.0N  111.8W 2.0-4.0 CBAAA  Utah area                  

 

MODERATELY LARGE QUAKE SHAKES NORTHERN CALIFORNIA COAST

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 22, 2017

 

The strongest earthquake in the world today occurred off the coast of northern California with M 5.7. NEIC reported it was felt with intensity II-III onshore at Ferndale, Loleta, Fortuna, Eureka, Arcata, Bayside, McKinleyville, Trinidad, Blue Lake, Fort Bragg, Willits, Potter Valley, Windsor, Petaluma, Arbuckle, Napa and at Central Point, Oregon. It was followed by an aftershock of M 3.9. NEIC reported it was felt with intensity II-III in California at Ferndale, Loleta, Fortuna, Petrolia, Eureka, Bayside, Meyers Flat and McKinleyville. A foreshock of M 3.0 was reported felt in Arcata, California. This appears to be the most recent in a series of migrating epicenters along the western coast of North America. This series has included an M 8.2 in Chiapas, Mexico; an M 7.1 near Mexico City; an M 5.5 in the Gulf of California and today's event of M 5.7 off northern California. Today's event may have been promoted by stresses from Hurricanes Jose and Maria as noted in the previous summary.

 

"Maria is expected to track directly north as a major hurricane along the continental slope perhaps encouraging a moderate earthquake along the North American-Pacific plate interface in the western U.S." (September 21-22, 2017)

 

and

 

"Seismicity in the western U.S. and Canada may increase as Jose makes a close approach to New Jersey. A moderate quake in the Vancouver or British Columbia region or southeastern Alaska could be promoted by stresses from Jose." (September 20, 2017)

 

The timing of today's mainshock off Northern California also suggests promotion The event occurred within about half an hour of local solar noon, a time of maximum tidal stresses associated with the new moon. This is the strongest

earthquake off the coast of Northern California within about 200 km of this epicenter since an M 6.5 on December 8, 2016 and prior to that on September 3, 2016 and January 28, 2015 - both with M 5.7. It is also the strongest earthquake in California since an M 5.7 in the California-Nevada border on December 28, 2016 and the largest in the state during the current year - 2017. Forecast 110538 had expected a moderate earthquake in the area within about 75 km of this epicenter was likely around September 21.

 

O: 22SEP2017 19:50:15  40.4N  126.9W Mw=5.7  EMSC   OFF COAST OF NORTHERN CALIFORNIA

O: 22SEP2017 19:50:15  40.4N  126.8W mw=5.7  ANSS   W of Ferndale California     

P: 21SEP2017 110538    40.9N  126.3W 2.5-4.6 AAAAA  Off Coast of No. Calif     

 

Light to moderate foreshocks and aftershocks including an M 3.9 about 200 km east of the mainshock

preceded and followed the M 5.7.

 

O: 22SEP2017 16:54:11  40.4N  125.4W ml=3.0  ANSS   WSW of Ferndale California   

O: 22SEP2017 16:54:13  40.4N  125.2W ML=3.3  EMSC   OFFSHORE NORTHERN CALIFORNIA

O: 22SEP2017 23:17:19  40.5N  124.4W ML=3.9  EMSC   OFFSHORE NORTHERN CALIFORNIA

P: 26SEP2017 110814    40.5N  124.7W 2.5-4.4 AAAAA  Off Coast of No. Calif     

P: 21SEP2017 110538    40.9N  126.3W 2.5-4.6 AAAAA  Off Coast of No. Calif     

 

Aftershocks also continued in the aftershock zone of the M 8.2 Chiapas quake in Mexico of September 8. The strongest of these today had magnitudes less than M 4.5.

 

 

O: 22SEP2017 08:04:53  14.9N   94.4W ML=4.1  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 22SEP2017 08:27:47  15.1N   94.5W ML=4.0  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 22SEP2017 16:21:44  15.3N   94.2W ML=4.3  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 22SEP2017 09:20:30  15.6N   95.0W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 22SEP2017 17:40:27  15.3N   94.6W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 22SEP2017 09:26:53  15.8N   95.1W ML=4.3  UNAM  l SUR de SALINA CRUZ, OAX *: 15

P: 22SEP2017 110686    15.0N   94.0W 3.5-5.6 AAAAA  Chiapas, Mexico             

P: 22SEP2017 110687    17.0N   95.0W 3.5-5.2 AAAAA  Chiapas, Mexico            

P: 22SEP2017 110704    15.0N   96.0W 3.5-5.5 AAAAA  Oaxaca, Mexico             

P: 24SEP2017 110687    16.0N   95.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

MODERATELY STRONG QUAKE IN GULF OF CALIFORNIA

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 21, 2017

 

A moderately strong earthquake of M 5.5 in the Gulf of California, Mexico continued the seismic activation of that nation today. This occurred two days after the remnants of Hurricane Norma passed over the area. This summary had expected a moderate to large quake in the Gulf of California associated with Norma at this time as:

 

"TS Norma continued today south of the Gulf of California, Mexico with winds up to 55 kts. It is expected to track directly north encountering seismic sections of the Gulf of California around September 18 and 19. A moderate earthquake in the Gulf of California is possible at that time." (September 17-19, 2017)

 

and in the previous issue of this summary:

 

"It is possible that stress migration in this case (Mexico, September 2017) is east to west and the next moderate quake in the sequence could be in the Baja or Gulf of California area rather than in Chiapas or Oaxaca." (September 20-21, 2017)

 

NEIC reported today's earthquake was felt with maximum intensity IV in La Palma, Sinaloa, Mexico but it was also reported felt with lesser intensity in Sinaloa at La Reforma, Culiacan, Mazatlan, at Puerto Vallarta, Jalisco; in Baja California at Rosarito, La Paz, Los Cabos, Cabo San Lucas and perhaps in San Diego, California, although this is unlikely. The last earthquake of M>=5.5 in the Gulf of California within about 200 km  of this epicenter was an M 6.2 on October 8, 2014. Two larger quakes since then - and M 6.6 on September 13, 2015 and an M 5.7 on March 29, 2017 occurred about 240 km northwest of today's epicenter. Forecast 110440 had expected a moderate earthquake in the Gulf of California around September 21.

 

O: 22SEP2017 05:33:45  23.5N  108.6W ML=5.1  UNAM  al NORESTE de SAN JOSE DEL CABO, B

O: 22SEP2017 05:33:47  23.6N  108.5W Mw=5.5  EMSC   GULF OF CALIFORNIA           

O: 22SEP2017 05:33:44  23.6N  108.8W mw=5.5  ANSS   Jose del Cabo Mexico

P: 21SEP2017 110440    25.0N  113.0W 3.5-5.1 ABCAA  Gulf of California         

 

The strongest earthquake in the U.S. or Canada today was an M 4.2 in Central Alaska. NEIC reported it was felt with intensity II in the Matanuska-Sustina Border, Talkeetna and Chugiak, Alaska. An earlier event of M 3.6 near Talkeetna, Alaska today was felt with intensity II in Skwentna and Wasilla, Alaska. This area has seen two other earthquakes of M 4.2-4.3 during 2017 - on September 13 and August 21, 2017. The last earthquake of larger magnitude in the area was an M 4.7 on November 17, 2016. Forecast 110583 had expected this event was likely within about 25 km around September 18.

 

O: 21SEP2017 22:15:21  62.8N  148.8W ML=4.2  EMSC   CENTRAL ALASKA               

P: 18SEP2017 110583    62.7N  149.3W 3.2-5.0 BAAAA  Central Alaska             

 

An M 4.0 also hit southeastern Alaska today near Skagway where it was reported felt with intensity II. Earthquakes Canada noted no felt reports nor tsunami were associated with this earthquake. This is the strongest earthquake within  about 100 km of this epicenter since an M 4.1 on August 10, 2015. The last of stronger magnitude was an M 4.3 on January 4, 2012. Forecast 110854 expected this event was likely within about 10 km of this epicenter around September 22.

 

O: 21SEP2017 10:09:16  58.1N  139.0W ML=4.1  NRCA  139 km SSE of Yakutat         

O: 21SEP2017 10:09:19  58.1N  139.0W ML=4.0  EMSC   OFF COAST OF SOUTHEASTERN ALAS

P: 22SEP2017 110854    58.0N  139.0W 3.0-4.4 AAAAA  Southeast Alaska           

 

A second event of M 2.7 hit the area near San Francisco today. This follows an M 2.7 in the San Francisco, California Bay area yesterday, the strongest in months. Today's earthquake was reported felt with intensity II-III in San

Martin, Gilroy, San Jose, Fremont, Millbrae, Concord, California. An M 2.5 in

the eastern foothills east of Fremont and north of San Jose was also felt earlier in the day. NEIC reported this event was felt with intensity II-III in  San Jose, Fremont, Sunnyvale, Mountain View, Los Gatos, Morgan Hill, Danville, San Francisco, Martinez and Napa, California. Forecasts 110741 and 110740 had expected this activity within about 25 km  was likely around September 24-27.

 

O: 22SEP2017 04:44:23  37.5N  121.8W MD=2.1  EMSC   SAN FRANCISCO BAY AREA, CALIF.

O: 21SEP2017 05:56:50  37.5N  121.8W MD=2.5  EMSC   SAN FRANCISCO BAY AREA, CALIF.

P: 24SEP2017 110741    37.8N  122.6W 2.5-4.6 BAAAA  Central California         

P: 27SEP2017 110740    37.3N  121.6W 2.5-4.4 CAAAA  Central California         

 

Aftershocks in the Chiapas and Oaxaca states of Mexico continued to be felt today. Reports of intensity II-III from these quakes were reported to NEIC from  Mixco, Guatemala; Mexico City and San Jose el Alto, Queretaro, Mexico.

 

O: 22SEP2017 05:07:23  14.8N   94.2W ML=4.0  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 21SEP2017 10:39:55  14.9N   94.1W ML=4.2  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 22SEP2017 08:04:53  14.9N   94.4W ML=4.1  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 21SEP2017 17:23:02  15.0N   94.1W mb=4.1  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 21SEP2017 04:07:46  15.0N   94.5W ML=4.0  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 21SEP2017 15:55:14  15.1N   93.7W ML=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 22SEP2017 08:27:47  15.1N   94.5W ML=4.0  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 21SEP2017 21:48:49  15.2N   94.5W ML=4.0  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 21SEP2017 20:22:31  15.3N   93.9W mb=4.8  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 22SEP2017 03:51:28  15.3N   94.7W ML=4.1  EMSC   OFF COAST OF OAXACA, MEXICO

O: 22SEP2017 09:20:30  15.6N   95.0W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 21SEP2017 21:34:59  15.7N   94.9W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 21SEP2017 11:44:28  15.8N   93.3W mb=4.8  EMSC   CHIAPAS, MEXICO

O: 21SEP2017 04:43:31  15.8N   95.1W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 22SEP2017 09:26:53  15.8N   95.1W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 21SEP2017 10:23:57  15.8N   95.2W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 22SEP2017 04:45:25  16.0N   95.2W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

P: 22SEP2017 110686    15.0N   94.0W 3.5-5.6 AAAAA  Chiapas, Mexico            

P: 22SEP2017 110687    17.0N   95.0W 3.5-5.2 AAAAA  Chiapas, Mexico            

P: 22SEP2017 110704    15.0N   96.0W 3.5-5.5 AAAAA  Oaxaca, Mexico             

 

 

IT ONLY TAKES A NUDGE

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 20, 2017

 

Global seismicity was at high levels today following the M 7.1 earthquake near Mexico City yesterday. In addition to triggering an eruption of Popocateptl in central Mexico, this earthquake and the M 8.2 event in Chiapas/Oaxaca, Mexico (in combination with the new moon tidal stresses) appear to have promoted strong earthquakes off the coast of Honshu, Japan (M 6.1) and Vanuatu (M 6.4) as well as moderately large quakes in Java/Bali (M 5.7-5.9) and New Guinea (M 5.9) today. The events in Japan and Vanuatu are located at 100-104 degrees from the activity in Mexico. Seismic energy is reflected and refracted off the core-mantle boundary and return to the surface in this distance range, and in a concentrated form can help trigger additional seismicity in this distance range. The event in Java was at 145 degrees from Mexico. Similar reflections off the inner-outer core return to the surface in this distance range with similar consequences on seismicity. These areas have seen increased seismicity since th M 8.2 on September 8 in Mexico but the additional stresses from the first new moon since the full moon of September 6 probably set off the strong flux of seismicity today. Previous summaries had anticipated most of this activity in associated with this new moon - it only takes a nudge to put the local stress over the rupture limit.

 

The M 6.1 off the east coast of Honshu, Japan today was reported by NEIC to have been felt with intensity II-III in Honshu in Iwate, Miyagi, Fukushima, Aomori, Akita, Ibaraki, Tochigi, Chiba, Saitama, Gunma, Tokyo, Nara, Yamanashi, Osaka and Hyogo Prefectures, Japan.

 

"Far Distance triggering from Chiapas today apparently included an M 4.6 in the Sea of Japan at 103 degrees from the Chiapas epicenter. Further activity in the Hokkaido area of M>=5 may be expected in the next several days." (September 10, 2017)

 

"A moderate earthquake of M 4.6 was widely felt in the region of Tokyo, Japan today. … A similar quake hit the area on September 10 with M 4.6 about 50 km to the west of today's epicenter.  The last earthquake in this area prior to September 10 of M>=4.6 was an M 4.6 on December 25, 2016. More recent activity to the east of this epicenter occurred on August 10 (M 5.1) and August 14, 2017 (M 4.8).  … This event is near the 103 degree triggering distance from the great Mexican quake of September 8. More, but larger, earthquakes from the Kurils to eastern Japan may be expected in coming days. (September 14, 2017)

 

This epicenter is on the outer rise of the Japanese subduction zone. This suggests some pent-up stress in the area and the possibility of a strong earthquake down the subduction zone near 38 North latitude. This is the strongest earthquake off the east coast of Honshu, Japan during the year 2017. The last events of M>=6.1 in the area occurred on November 11 and November 21, 2016 (M 6.2 and 6.9) and prior to that on May 12, 2015. The current quiet in the region is likely due to the stress shadow from the March 11, 2011 event of M 9.3. This was most recently noted in the summary of September 18 as:

 

"The last earthquake within about 100 km of this epicenter occurred on July 20, 2017 with a new moon. This is in the shadow of the M 9+ quake of March 11, 2011 and should be relative quiet for many years as the stress has been largely removed with that quake. Forecast 110482 had expected this event around September 14. This epicenter is at 105 degrees (a distance at which triggering is likely) from the great Mexican earthquake and was probably promoted from that source." (September 18, 2017)

 

Both this event in Japan and an M 5.3-5.7 south in Taiwan may be delayed from

Typhoon Talim which passed over these areas earlier this week. This summary had expected this as:

 

"Typhoon Talim continued west of the Mariana Islands today with winds up to 80 kts. It is expected to track towards Taiwan over the next two days  reaching typhoon levels around September 14. Seismicity in the Mariana and Volcano Islands and in the Northern Philippines and Taiwan is expected to increase as this storm passes through the region. A seismic watch is in effect for the areas of Guam, northern Philippines and Taiwan through September 16." (September 15, 2017)

 

The area was placed under a seismic advisory in this summary on September 18 as:

 

"Typhoon Talim continued over Honshu and Hokkaido, Japan today with winds up to 70 kts. A moderate earthquake in Japan is likely as this storm passes through the region. The area of Honshu and Hokkaido and the Kuril Islands is under a seismic advisory through September 19." (September 17-19, 2017)

 

The distance from the great Mexican earthquake of September 8 to this epicenter is 103 degrees, supporting the hypothesis that it was a triggered event. But it only takes a nudge. Forecast 110778 had expected this activity was likely around September 22.

 

O: 20SEP2017 16:37:16  38.0N  144.7E Mw=6.1  EMSC   OFF EAST COAST OF HONSHU, JAPA

O: 20SEP2017 16:37:16  38.0N  144.7E mw=6.1  ANSS   ESE of Kamaishi Japan

P: 22SEP2017 110778    39.0N  143.0E 4.0-5.4 AAAAA  So. of Honshu              

 

As noted above, a moderately strong quake of M 5.3-5.7 shook Taiwan today.

No damage or casualties were reported. This is the strongest earthquake in Taiwan this year. An M 5.4 hit the area on April 30, 2017. The last event in Taiwan of M>5.3 was an M 5.7 on October 6, 2016. This is near the third node (120 degrees) from the M 7.1 in Central Mexico yesterday and may have been promoted from that source as well. NEIC reported this earthquake of M 5.3 in Taiwan was felt with intensity IV in Shalu, Taitung and II-III in the area(s) of Hualien, Taichung, Changhwa, Kaohsiung, Tainan, Hsinchu, Taoyuan, Taipei, Keelung and in mainland China at Quanzhou, Fujian. CWB reported this earthquake was felt with intensity V in Taitung; IV in Hualien; III in Chiayi, Yunlin, Tainan and Changhua; II in Taitung, Nantou, Kaohsiung, Taichung, Yilan, Pingtung, Chiayi, Yunlin, Miaoli, and I in Taoyuan, Hsinchu, Taipei and Penghu Counties, Taiwan. Forecast 110451 had expected this event was likely around September 19.

 

 

O: 20SEP2017 14:29:56  23.3N  121.8E ML=5.7  TAI    Hualien, Taiwan              

O: 20SEP2017 14:29:55  23.3N  121.9E Mw=5.3  EMSC   TAIWAN                       

P: 19SEP2017 110451    23.0N  121.0E 4.0-5.4 AAAAA  Taiwan                     

 

NEIC reported the M 6.4 in Vanuatu was probably felt with intensity IV and reported with intensity III in Vila, Shefa, Vanuatu. The M 6.4 was preceded by an M 4.7 in central Vanuatu about five hours earlier. That event was at 103 degrees from the M 8.2 Mexican shock. It only takes a nudge.

 

"This event in Guatemala is ... at 103 degrees from a tidally triggered event of Vanuatu  of M 5.8 which occurred about seven hours earlier. This is a distance at which seismic energy reflected and refracted off the core-mantle boundary returns in concentrated state to the surface. Seismicity subsequently often increases this distance range, probably due to the arriving energy. When an area is near rupture this can be precipitated by a large but non-major earthquake ...  Was the area of Chiapas-Guatemala ready for such a triggered event? This summary has been following an escalation of seismicity in Guatemala and Chiapas, Mexico over the past several days which began with the passage of Tropical Depression Calvin over these epicenters and was noted in the previous issue of this summary" (June 14, 2017) - repeated in the summary of September 8, 2017 following the great Mexican quake.

 

Today's epicenter is located at 101-102 degrees from the great M 8.2 quake in  Mexico of September 8. As noted above this probably was promoted by concentrated energy reflected to this distance on the surface. It only takes a nudge.

 

An earthquake of M 5.8 hit in Vanuatu near this epicenter on June 14 with the first of the Guatemala/Chiapas Mexico quakes (M 6.7). At M 6.4 this is the largest event in Vanuatu within about 500 km of this epicenter since an M 7.0 about 400 km north of this on April 28, 2016. The last within 200 km was an M 6.7 on March 9, 2012 but it only takes a nudge. Forecast 110892 had expected this event was likely within about 100 km of the epicenter around September 25.

 

O: 20SEP2017 20:09:50  18.8S  169.1E Mw=6.4  EMSC   VANUATU                      

O: 20SEP2017 20:09:49  18.8S  169.1E mw=6.4  ANSS   NNW of Isangel Vanuatu

P: 25SEP2017 110892    19.0S  170.0E 4.0-5.4 BAAAA  Vanuatu Islands            

 

O: 20SEP2017 15:32:28  14.9S  167.0E mb=4.7  EMSC   VANUATU                      

P: 19SEP2017 110612    15.0S  167.0E 4.0-5.6 AAAAA  Vanuatu Islands            

 

A strong earthquake of M 5.9 also hit regions of eastern New Guinea today. It was probably felt in the epicentral area. It was followed by aftershocks of M 4.7 and 5.2 among others. This is the strongest earthquake in this area since an M 5.9 on January 8, 2017. The last event within about 150 km of this epicenter with M>5.9 was an M 6.9 on October 17, 2016 about 150 km southeast of today's epicenter but it only takes a nudge. This epicenter is at the third node (120 degrees) from the great Chiapas earthquake of September 8. Forecast 110395 had expected today's quake was likely around September 17 in  this region.

 

O: 20SEP2017 22:13:35   5.1S  147.9E Mw=5.9  EMSC   EASTERN NEW GUINEA REG., P.N.G

O: 20SEP2017 22:13:36   5.1S  147.8E mw=5.9  ANSS   Finschhafen Papua New Guinea

O: 20SEP2017 22:36:07   5.1S  148.0E mb=4.7  EMSC   NEW BRITAIN REGION, P.N.G.   

O: 20SEP2017 22:17:24   5.2S  148.0E mb=5.2  EMSC   EASTERN NEW GUINEA REG., P.N.G

P: 17SEP2017 110395     6.0S  149.0E 4.0-5.4 BAAAA  New Ireland                

 

The earthquake of M 5.7 in Java was reported by NEIC to have been felt in Bali at Denpasar and Kuta, Indonesia. BMG reported this earthquake was felt with intensity III in Denpasar, Bali, Indonesia. This is the strongest earthquake this year in the regions near Java and Bali. The last event within about 200 km of this epicenter with M>=5.7 was an M 5.9 on June 6, 2004 but it only takes a nudge.  Forecast 110400 had expected this event within about 10 km of the epicenter was likely around September 19. This epicenter is located at 145-146 degrees from the Mexico City M 7.1 quake yesterday, a distance at which triggering is expected from concentrated seismic energy released in that earthquake.

 

O: 20SEP2017 23:59:24   6.1S  113.0E Mw=5.7  EMSC   JAVA, INDONESIA              

O: 20SEP2017 23:59:24   6.1S  113.0E mw=5.7  ANSS   NNE of Kemeduran Indonesia

O: 20SEP2017 23:59:22  06.3S  113.0E MS=5.2  BMG  Felt with intensity III

P: 19SEP2017 110400     6.0S  113.0E 4.0-5.4 AAAAA  So. of Bali                

 

The strongest earthquake in California today was an M 3.6-3.7 in Northern California. NEIC reported it was felt with maximum intensity IV in California at Bella Vista, Oak Run, Whitmore, and II-III in Montgomery Creek, Burney, Lakehead, Redding, Millville, Shasta Lake, Palo Cedro, Shingletown, Hat Creek, Anderson, Mount Shasta, McArthur, Cottonwood, Red Bluff, Herlong, Danville.

This is the strongest earthquake in Northern California within about 100 km  of this epicenter since an M 4.4 on May 10, 2005 more than 12 years ago. The area may see water-related triggering and effects from the new moon and the  earthquakes in Mexico could have helped promote this event at this time.  Forecast 110536 had expected this event around September 19 within about 50 km of this epicenter.

 

O: 20SEP2017 17:48:39  40.9N  122.0W MD=2.1  EMSC   NORTHERN CALIFORNIA          

O: 20SEP2017 17:10:08  40.9N  122.0W ML=3.6  EMSC   NORTHERN CALIFORNIA          

P: 19SEP2017 110536    40.7N  122.3W 2.5-4.6 AAAAA  Northern California        

 

An earthquake of M 2.7 was felt today in the area of San Francisco, California. NEIC reported intensity II-III in Pleasant Hill, Walnut Creek, Lafayette, Martinez, Pittsburg, Berkeley, Suisun City, Oakland, San Ramon, Discovery Bay, San Jose, California. San Francisco has seen a series of light earthquakes in the past week, possibly related to the strong solar flares of last week and the moderate geomagnetic storm which followed or to the great Mexican quake of September 8. The last earthquake in the San Francisco Bay area of M>=2.7 was an M 4.0 on June 21. The only event which exceeded M 3.0 this year was an M 3.8 on April 30, 2017. Forecast 110741 had expected today's event was likely around September 24 within about 50 km of this epicenter.

 

O: 21SEP2017 00:07:39  38.0N  122.1W MD=2.7  EMSC   SAN FRANCISCO BAY AREA, CALIF.

P: 24SEP2017 110741    37.8N  122.6W 2.5-4.6 BAAAA  Central California         

 

Aftershocks in Chiapas and Oaxaca continued today but there were no events of M>5.1. A quiet day in the aftershock sequence. None of these were reported felt in the area. It is possible that stress migration in this case is east to west and the next moderate quake in the sequence could be in the Baja or Gulf of California area rather than in Chiapas or Oaxaca.

 

O: 20SEP2017 09:40:43  15.1N   94.4W ML=4.4  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 20SEP2017 07:15:31  15.1N   94.5W ML=4.1  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 20SEP2017 10:39:28  15.3N   93.4W mb=4.7  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 20SEP2017 09:29:06  15.5N   94.8W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 20SEP2017 14:37:25  15.7N   95.1W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 20SEP2017 23:54:18  15.7N   95.2W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 20SEP2017 08:13:30  15.9N   95.1W ML=4.6  EMSC   OFFSHORE OAXACA, MEXICO

O: 20SEP2017 10:39:26  15.0N   93.6W ML=5.1  UNAM  l SUROESTE de PIJIJIAPAN, CHIS *:

O: 21SEP2017 00:44:18  15.0N   93.6W ML=4.5  EMSC   OFFSHORE CHIAPAS, MEXICO     

P: 22SEP2017 110686    15.0N   94.0W 3.5-5.6 AAAAA  Chiapas, Mexico            

P: 22SEP2017 110687    17.0N   95.0W 3.5-5.2 AAAAA  Chiapas, Mexico            

P: 22SEP2017 110704    15.0N   96.0W 3.5-5.5 AAAAA  Oaxaca, Mexico             

 

No moderate aftershocks followed the M 7.1 in Central Mexico. Two minor events near the epicenter did occur with M 2.3 and 1.9. This lack of aftershocks can be interpreted in two ways. A great deal of pent up stress remains in the area and is locked or the triggering conditions which brought on the initial shock were of sufficient magnitude to push a fault that was not ready to go over the rupture edge.

 

O: 20SEP2017 08:17:59  20.3N   99.0W ML=2.3  UNAM  l NOROESTE de ACTOPAN, HGO *: 2

P: 27SEP2017 110722    20.0N   99.0W 3.0-4.6 CAAAA  Northern Mexico            

 

O: 20SEP2017 08:03:53  19.3N   99.3W ML=1.9  UNAM   SUR de CUAJIMALPA, CDMX *: 19.

P: 19SEP2017 110430    19.0N   99.0W 3.5-5.2 AAAAA  Oaxaca, Mexico             

 

 

MAJOR EARTHQUAKE DEADLY IN CENTRAL MEXICO - THE OTHER SHOE DROPS

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 19, 2017

 

A major earthquake of M 7.1 hit the Mexican State of Puebla today, apparently dropping the other shoe anticipated in this summary of September 12. This deadly earthquake was widely felt in the area of Mexico City and surroundings where it was deadly and caused buildings to collapse. A state of disaster has been declared for Mexico City. NEIC reported maximum intensity IX in Puebla at Raboso, Puebla and Emiliano Zapata, Moreles, and VIII in Puebla at Atlixco, Chiautia, Atzompa, and in Morelos at Xochitepec, Cocyoc, Tlayacapan, in the State of Mexico at Juchitepec, Montecillo, Malinalco, Chimalpa, Mexico City, Jilozingo,  and in general within about 150 km of the epicenter. It was felt with intensity V-VI as far as Veracruz, Queretaro, Guanajuato, and V in Jalisco, Chiapas more than 700 km from the epicenter. Maximum intensity VII was felt within about 100 km of the epicenter in areas including those in Puebla at Chautia, Cholula, Puebla, Cuautlancingo, Momoxpan, Aparicio, Almecatla, Atlatlahucan, Tepoztlan, Mexico. More than 250 were confirmed dead in this earthquake which hit about 120 km south of Mexico City near local solar noon.

The devastated remains of schools, apartment buildings, homes and businesses throughout the area were being searched for survivors. The quake occurred hours after an earthquake drill commemorating the 32nd anniversary of Mexico's deadliest quake - an M 8.1 on September 19, 1985 which killed more than 35,000. Today's quake while not as large or deadly occurred much closer to Mexico City. Confirmed deaths per state included: Morelos 72; Puebla 43; Mexico City 117; Mexico State 12; Guerrero 3 and Oaxaca 1. Thousands were injured and many children were missing in collapsed schools. The timing of the quake near noon was particularly bad for school children most of whom were in school at the time. At least 44 high rise buildings in Mexico City collapsed or were severely damaged in the quake. Because Mexico City is built on filled soil in an old swamp shaking is amplified and often leads to higher destructive power of large earthquakes. Tolls in all categories of death and destruction will rise in coming days. It is the worst quake in Mexico City since September 1985. A second quake on September 21, 1985 of M 7.1 contributed to the damage and deaths in that catastrophe.

 

The timing of today's earthquake near local solar noon in conjunction with the new moon alignment strongly suggests tidal triggering to this event. This summary had noted this possibility in the last summary as:

 

 

"The new moon will arrive at 05:30 UT on September 20. Longitudes which are sub-solar at this time are near 98 East and those anti-solar are near 82 West longitude. These include the same areas subject to high tidal stresses in the last new moon/eclipse of August 21. Areas in the west include the Mexican and central American and South American subduction zones while those in the east include western Indonesia and southeast Asia. These are the most likely to see tidal triggering in the next week. A strong regional aftershock in Mexico continues to be a possibility." (September 17-18, 2017)

 

Earlier indications had pinpointed this region of Mexico as an area to watch for a subsequent possibly major event as noted on the day of the M 8.2 in Chiapas, Mexico in this summary:

 

"A second epicenter in the Mexican Subduction Zone also saw a swarm of  moderate events today. This area became active at local solar midnight and was probably activated by solar flares and tidal stresses which maximize their effects at this time." (September 8, 2017)

 

And on September 14 it was noted:

 

"TS Max formed today south  of central Mexico with winds up to 55 kts. It is expected to track to the north making landfall near Acapulco, Mexico early on September 15. As it reaches areas north of the subduction zone, atmospheric unloading could promote a moderate to strong earthquake near the eye (about 16-17N 99-100W). This area is under seismic watch for the next three days through September 18." (September 14, 2017)

 

The main promoter of today's earthquake however appears to be landfall of Hurricane Maria on the Caribbean. Maria is a major category 5 hurricane with gusts up to 225 mph and sustained winds of around 175 mph. It hit the same area of the Caribbean today as the similar hurricane - Irma did on September 8 as the M 8.2 quake hit Chiapas, Mexico. Horizontal motions of the tectonic plates associated with these storms probably triggered both events. The two cases are completely analogous. Previous summaries had noted the effect of Irma on the area of Chiapas as follows:

 

" (The earthquake in Chiapas) is also directly west of  Hurricane Irma. Stresses on land associated with Irma probably were the major promotional effect triggering this earthquake" (September 8, 2017)

 

"This earthquake was probably triggered by a combination of plate motions induced from Hurricane Irma (horizontal) and Hurricane Katia (vertical) ...

 

The remarkable resemblance of the paths (and effects) of Hurricanes Irma and Maria had previously been noted in this summary as:

 

"After striking Puerto Rico, the path (of Maria) is uncertain but the resemblance of this path to that of Hurricane Irma is remarkable" (September 17-18, 2017)

 

Like the M 8.2 on September 8, today's event of M 7.1 also was associated with strong geomagnetic activity. The M 8.2 occurred as the CME from the strongest flare in 12 years hit the earth. Geomagnetic activity also peaked yesterday at the strongest levels (KP 7) since September 8 and was probably also  promotional to the Mexican earthquake today as noted in the previous summary:

 

"The geomagnetic field was at active conditions today.  The AP level was 22.

High latitude geomagnetic field saw major storms with AP at 51. Strong seismicity is still possible within 10-15 degrees from the geomagnetic equator and at high auroral latitudes around September 18-21." (September 19, 2017)

 

The last earthquake of M>=7.1 in the Puebla State of Mexico within about 200 km of this epicenter was an M 7.2 on April 18, 2014 about 200 km southwest of today's event. That was the only such earthquake in the area in at least 25 years.  Forecast 110430 had expected today's activity was likely on September 19 within about 50 km of this epicenter.

 

O: 19SEP2017 18:14:40  18.4N   98.7W ML=7.1  UNAM  l SURESTE de AXOCHIAPAN, MOR *: 18

O: 19SEP2017 18:14:38  18.6N   98.5W Mw=7.1  EMSC   PUEBLA, MEXICO               

O: 19SEP2017 18:14:40  18.4N   98.7W ML=7.1  UNAM  l SURESTE de AXOCHIAPAN, MOR *: 18

O: 19SEP2017 18:14:39  18.6N   98.4W mw=7.1  ANSS   ENE of Raboso Mexico

P: 19SEP2017 110430    19.0N   99.0W 3.5-5.2 AAAAA  Oaxaca, Mexico             

 

A remarkable series of earthquakes in New Zealand today followed the M 7.1 in Central Mexico. The largest of these was an M 6.1 in the Auckland Islands of southern New Zealand, but moderate earthquakes hit in the Cook Strait (M 5.0)  and north of North Island as well. The M 6.1 in the Auckland Islands is the strongest in that area since an M 6.5 on July 11 northeast of this epicenter. A similar event was reported on August 4 with M 4.6. Forecasts 110923 and 110630 had expected this activity in mid-September. This summary had previously noted that strong earthquakes in New Zealand were likely at this time as it is located at 101-108 degrees from the Chiapas, Mexico M 8.2, a distance at which triggering often occurs following major earthquakes.

 

NEIC reported this earthquake of M 6.1 in the Auckland Islands, New Zealand was felt with intensity II-III in the area(s) of Dunedin, Otago, South Island and Greytown, Wellington, North Island, New Zealand.

 

O: 20SEP2017 01:44:36  46.7S  168.0E ML=4.8  EMSC   OFF W. COAST OF S. ISLAND, N.Z

P: 13SEP2017 110638    46.0S  167.0E 3.0-5.1 CAAAA  Southern S. Isl. N.Z.      

 

O: 20SEP2017 01:43:30  50.4S  162.6E Mw=6.1  EMSC   AUCKLAND ISLANDS, N.Z. REGION

O: 20SEP2017 01:43:30  50.4S  162.5E mw=6.1  ANSS   Auckland Island New Zealand

P: 28SEP2017 110923    47.0S  165.0E 3.0-5.1 CCBAA  Southern S. Isl. N.Z.      

 

An earthquake in the Cook Strait of New Zealand was also widely felt today. GEONET reported it was felt with moderate intensity in the area of northern South Island and southern North Island, New Zealand. 3430 people reported feeling this earthquake including 965 with weak intensity; 1776 with light intensity; 611 with moderate shaking; 76 with strong intensity and one with extreme intensity. No damage was reported.  NEIC reported this earthquake of M 5.0 in Cook Strait, New Zealand was felt with intensity II-III in the area(s) of Wellington and IV in Makara-Ohariu, New Zealand. This is the largest earthquake in the Cook Strait since M 5.2 on January 5, 2017. Forecast 110636 had expected this event within about 100 km of the epicenter was likely around September 21.

 

O: 20SEP2017 02:42:09  41.5S  174.4E mb=5.0  EMSC   COOK STRAIT, NEW ZEALAND     

O: 20SEP2017 02:42:10  41.8S  174.3E ML=5.3  GEONET Felt with moderate intensity

P: 21SEP2017 110636    41.0S  175.0E 3.0-4.9 AAAAA  So. Island, N.Z.           

 

O: 19SEP2017 23:05:04  36.4S  179.7E mb=4.7  EMSC   OFF E. COAST OF N. ISLAND, N.Z

P: 26SEP2017 110913    35.0S  179.0E 3.0-4.5 CBAAA  North Island, N.Z.         

 

The strongest earthquake in the U.S. or Canada outside Alaska today was an M 3.8 in Illinois. This appears to be a delayed eclipse earthquake lying on the path of totality of the August 21, 2017 solar eclipse. It is similar to an earthquake in Illinois which occurred with the greate M 8.2 in Mexico on September 8, but, unlike  that event today's occurred before the Mexican quake, not after. NEIC reported today's earthquake in Illinois was felt with maximum intensity IV in Mount Carmel, Bone Gap, Browns, West Salem, Illinois. It was also reported felt with lesser intensity through much of Illinois, Indiana and Missouri up to about 400 km from the epicenter. No damage or casualties were reported with this earthquake. The earthquake of September 9 was M 3.2. The last of M>=3.8 within about 150 km of this Illinois epicenter occurred on April 18, 2008 with M 5.4 with an aftershock of M 4.0 on April 21, 2008. Forecast 110474 had expected today's event in this region was likely around September 16.

 

O: 19SEP2017 11:47:28  38.4N   87.9W Mw=3.8  EMSC   ILLINOIS                     

P: 16SEP2017 110474    38.0N   89.0W 2.0-4.3 BAAAA  New Madrid area            

 

The strongest earthquakes in California today were a pair of M 3.2 and 3.7 in the Coso Junction area of central California. The first of these at 23 degrees from the Mexico City quake occurred several minutes after surface waves from that event arrived at this epicenter. This was probably the trigger for the subsequent California seismicity. These two events were part of a swarm in the region including an M 2.0 at 1430 UT but showed considerable increase in magnitude after the Mexican quake which suggests a triggering effect. The last earthquake within about 50 km of today's activity was an M 3.7 on May 25, 2017 but the last of larger magnitude occurred more than three years ago on March 15, 2014 with M 4.0. Forecast 110495 had expected today's earthquakes were likely within about 10 km of these epicenters around September 18.

 

NEIC reported this earthquake of M 3.7 in Little Lake north of Coso Junction  was felt with intensity II-III in the area(s) of Porterville, Burbank, Los Angeles, California. It followed a M 3.2 event in the same area.

 

O: 19SEP2017 14:30:25  36.0N  117.8W ML=2.0  EMSC   CENTRAL CALIFORNIA           

O: 19SEP2017 16:56:50  36.0N  117.8W ML=2.5  EMSC   CENTRAL CALIFORNIA           

O: 19SEP2017 18:34:13  36.0N  117.8W ML=3.2  EMSC   CENTRAL CALIFORNIA           

O: 19SEP2017 18:45:43  36.0N  117.8W ML=3.7  EMSC   CENTRAL CALIFORNIA           

P: 18SEP2017 110495    35.9N  117.7W 2.5-4.4 AAAAA  So. California             

 

The strongest earthquake in Alaska was an M 4.8 in the Rat Islands where it was not felt. The last earthquake of M>=4.8 in the Rat Islands was an M 4.9 near today's epicenter on August 18. Forecast 110571 had expected this event was likely around September 15.

 

O: 19SEP2017 14:49:35  52.0N  178.1E mb=4.8  EMSC   RAT ISLANDS, ALEUTIAN ISLANDS

P: 15SEP2017 110571    52.0N  178.0E 4.0-5.8 BAAAA  Rat Islands                

 

Aftershocks also continued in the Chiapas/Oaxaca zone today. The strongest of these was lightly felt with M 5.4.

 

NEIC reported an earthquake of M 4.6 in Oaxaca, Mexico was felt with intensity II-III in the area(s) of Tehuantepec, Oaxaca and Coatepec, Mexico.

 

O: 19SEP2017 09:00:41  15.0N   94.3W ML=4.0  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 19SEP2017 09:47:03  15.1N   93.7W ML=4.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 19SEP2017 09:03:21  15.1N   93.8W ML=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 19SEP2017 07:53:16  15.1N   94.1W Mw=5.4  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 20SEP2017 09:40:43  15.1N   94.4W ML=4.4  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 20SEP2017 10:39:29  15.3N   93.4W mb=4.7  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 19SEP2017 21:13:18  15.3N   94.6W mb=4.9  EMSC   OFF COAST OF OAXACA, MEXICO

O: 19SEP2017 09:42:01  15.4N   94.7W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 19SEP2017 07:20:18  15.4N   94.8W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 19SEP2017 09:35:35  15.5N   94.7W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 19SEP2017 07:03:02  15.7N   94.6W mb=4.9  EMSC   OFFSHORE OAXACA, MEXICO

O: 20SEP2017 04:15:51  15.9N   94.8W mb=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 20SEP2017 08:13:30  15.9N   95.1W ML=4.6  EMSC   OFFSHORE OAXACA, MEXICO

O: 20SEP2017 04:49:17  16.0N   95.1W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 20SEP2017 03:28:05  16.1N   94.9W mb=4.6  EMSC   OFFSHORE OAXACA, MEXICO

O: 19SEP2017 23:11:34  16.3N   94.7W mb=4.6  EMSC   OAXACA, MEXICO

 

 

STRONG CHILE QUAKE TRIGGERS STRONG AFTERSHOCK IN MEXICO

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 18, 2017

 

A strong M 5.8-5.9 earthquake in Central Chile off the coast of Coquimbo, Chile occurred near local noon today and was widely felt. It was followed 32 minutes later by a similar event of M 5.6-5.8 in the aftershocks zone of the M 8.2 of September 8 in Chiapas and Oaxaca, Mexico. It appears that seismic reflections off the core boundaries from Chile dynamically triggered the strong Mexican aftershock. The strongest earthquake (M 3.6) in the area of western Los Angeles, California in more than 2 years also occurred today and was widely felt near local midnight.

 

An M 5.9 earthquake shook the area of Central Chile near Valparaiso today. NEIC reported maximum felt intensity of VI was felt in Quilpue and Valparaiso. Intensity V was reported from Vina del Mar, Quillota, Villa Alemana, and San Antonio with IV in Lampa, Santiago, Rancagus, San Vicente, Salamanca and III in Illapel, La Ligua and Calera. CSN reported it at M 5.7 and noted it was felt with maximum intensity V in  Llaillay; IV Canela, Combarbala, Los Vilos, Papudo, Petorca, Putaendo, Valparaiso, Tiltil; III Navidad, Mostazal, Graneros, Santiago, Puente Alto, Maria Pinto, Curacavi, Santo Domingo, Quillota, Salamanca, Illapel. Felt in Coquimbo, Valparaiso, Santiago and O'Higgins, Chile.

No major damage was reported from this ofshore earthquake. No tsunami was expected nor observed. The last earthquake within about 200 km of this epicenter was an M 5.7 on June 12, 2017 and an M 5.8 on August 12, 2017. An M 6.3 north of this by about 200 km occurred on February 10, 2016. This is probably an aftershock of an M 8.3 which hit within about 50 km of today's epicenter nearly exactly two years ago on September 16, 2015. Forecast 110627 had expected this quake about 100 km  to the south around September 17.

 

NEIC reported this earthquake of M 5.6 in Chiapas, Mexico was felt with maximum intensity IV in the epicentral area. This epicenter is located at 51.4 degrees from the great Mexican quake of September 8 (exact node 7) and was probably promoted from that source.

 

O: 18SEP2017 15:35:20  31.8S   72.2W mb=4.3  EMSC   OFFSHORE COQUIMBO, CHILE

O: 18SEP2017 14:28:55  31.9S   72.2W mb=4.3  EMSC   OFFSHORE COQUIMBO, CHILE

O: 18SEP2017 13:46:56  31.8S   72.1W mw=5.8  ANSS   WSW of Illapel Chile

O: 18SEP2017 13:46:56  31.8S   72.1W mw=5.7  GUC    WSW of Illapel Chile

O: 18SEP2017 13:47:00  31.8S   71.8W Mw=5.9  EMSC   OFFSHORE COQUIMBO, CHILE     

P: 17SEP2017 110627    33.0S   71.0W 4.0-5.6 ABAAA  Central Chile              

 

The earthquake in Chile was followed by an M 5.6-5.8 in eastern Mexico 32-33 minutes later at a distance of 51.5 degrees (node 7). As PkkP waves from Chile arrived in Mexico at the time of the initiation of the second quake, it appears the event in Mexico was dynamically triggered by these waves from the Chile earthquake. No major damage or tsunami was expected nor reported from these aftershocks. Forecasts 110409, 110428 and 110686 had expected this activity in mid-September.

 

O: 18SEP2017 14:19:10  14.7N   94.8W ML=5.8  UNAM  al SUR de SALINA CRUZ, OAX *: 14.7

O: 18SEP2017 14:19:12  15.3N   94.6W mw=5.6  ANSS   Francisco del Mar Mexico

O: 18SEP2017 14:19:12  15.2N   94.7W Mw=5.6  EMSC   OFF COAST OF OAXACA, MEXICO

O: 19SEP2017 07:53:18  15.2N   94.0W Mw=5.4  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 18SEP2017 13:41:56  15.1N   94.4W ML=4.3  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 18SEP2017 15:13:59  15.2N   94.6W mb=4.7  EMSC   OFF COAST OF OAXACA, MEXICO

O: 18SEP2017 22:13:33  15.2N   94.7W mb=4.2  EMSC   OFF COAST OF OAXACA, MEXICO

O: 18SEP2017 19:51:32  15.3N   94.6W mb=4.9  EMSC   OFF COAST OF OAXACA, MEXICO

O: 19SEP2017 01:11:42  15.3N   94.7W ML=4.3  EMSC   OFF COAST OF OAXACA, MEXICO

O: 19SEP2017 01:45:47  15.3N   94.7W ML=4.4  EMSC   OFF COAST OF OAXACA, MEXICO

O: 18SEP2017 09:19:21  15.3N   94.8W ML=4.0  EMSC   OFF COAST OF OAXACA, MEXICO

O: 19SEP2017 06:15:59  15.4N   94.1W ML=4.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 19SEP2017 07:20:18  15.4N   94.8W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 18SEP2017 06:04:24  15.5N   94.1W ML=4.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 19SEP2017 01:23:26  15.5N   94.4W mb=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 19SEP2017 04:20:05  15.5N   94.8W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 19SEP2017 00:59:57  15.5N   95.1W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 18SEP2017 17:53:57  15.5N   95.2W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 18SEP2017 17:57:35  15.5N   95.2W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 19SEP2017 05:21:32  15.6N   94.8W ML=4.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 18SEP2017 17:49:40  15.6N   95.3W ML=4.6  EMSC   OFFSHORE OAXACA, MEXICO

O: 18SEP2017 07:31:28  15.7N   94.5W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 18SEP2017 08:41:04  15.7N   94.5W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 19SEP2017 07:03:02  15.7N   94.5W mb=4.9  EMSC   OFFSHORE OAXACA, MEXICO

O: 19SEP2017 03:26:25  15.7N   95.2W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 18SEP2017 21:16:05  15.8N   95.0W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 18SEP2017 23:29:55  15.8N   95.1W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 18SEP2017 17:25:42  15.8N   95.2W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 18SEP2017 12:07:01  16.2N   95.1W mb=4.9  EMSC   OFFSHORE OAXACA, MEXICO

O: 19SEP2017 09:29:14  17.0N   96.9W ML=4.2  EMSC   OAXACA, MEXICO

O: 18SEP2017 15:59:17  15.0N   94.2W ML=4.3  EMSC   OFF COAST OF CHIAPAS, MEXICO 

P: 18SEP2017 110409    14.0N   94.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

P: 18SEP2017 110428    16.0N   97.0W 3.5-5.3 AAAAA  Oaxaca, Mexico             

P: 22SEP2017 110686    15.0N   94.0W 3.5-5.6 AAAAA  Chiapas, Mexico            

 

The strongest earthquake in the U.S. or Canada outside Alaska today was an M 3.6 in Los Angeles, California. NEIC reported it was felt with maximum intensity V in Los Angeles and IV in Beverly Hills, Santa Monica. Lesser shaking within about 40 km of the epicenter was felt with MMI II-III in California at Pasadena, Simi Valley, Hermosa Beach, Manhattan Beach, Porter Ranch, West Hills, Burbank, Northridge, Woodland Hills, Playa del Rey, Los Angeles, North Hollywood, Reseda, Culver City, Venice, Van Nuys, Tarzana, Encino, Santa Monica, West Hollywood, Sherman Oaks, Pacific Palisades, California.  The location of this epicenter south of the Simi Valley, California reminds that 2017 is the 22nd year in

a repeating 22 or 23 year cycle of large earthquakes around M 6.7  in the area.

In the past two cycles this has included the San Fernando quake of February, 1971 and the Northridge quake of January, 1994, both destructive in the area. Both had notable foreshocks to the south in the general vicinity of today's epicenter several days before their respective mainshocks. Conditions may ripe for a moderate quake in the area with seismic effects of one of the largest quakes ever recorded in Chiapas, Mexico; landfall of Hurricane Jose and later Maria occurring in concert with the full moon on September 20. These could help promote regional seismicity at this time. The last earthquake in Los Angeles of M>=3.6 within about 50 km of this epicenter was an  Forecasts 110491 and 110772 had expected this event in mid-September. The last earthquake of M>=3.6 in this area occurred nearly 2.5 years ago as an M 3.8 on May 3, 2015.

 

O: 19SEP2017 06:20:44  34.1N  118.5W ML=3.6  EMSC   GREATER LOS ANGELES AREA, CALI

O: 19SEP2017 06:20:44  34.1N  118.5W ml=3.6  ANSS   NW of Westwood CA

P: 13SEP2017 110491    34.4N  118.6W 2.5-4.4 CAAAA  So. California             

P: 25SEP2017 110772    33.9N  118.3W 2.5-4.5 CAAAA  So. California             

 

The strongest earthquake in Alaska today was an M 4.3 in the Andreanof Islands, Aleutians where it was not reported felt. The last earthquake of M>=4.3 within about 100 km of this epicenter was an M 5.4 on September 11, 2017. Today's event appears to be an aftershock of the September 11 quake. Forecast 110557 had expected this event in this region around September 16.

 

O: 18SEP2017 14:32:54  51.6N  178.4W ML=4.3  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P: 16SEP2017 110557    51.7N  179.7W 3.5-5.3 AAAAA  Andreanoff Isls, Aleutians 

 

SEISMICITY ALONG GEOMAGNETIC EQUATOR ACTIVE

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 17, 2017

 

The strongest earthquakes of the day occurred with M 5.7 within about 10 degrees of the local geomagnetic equator. These events in the southern mid-Atlantic Ridge and New Guinea followed the pattern expected after major geomagnetic storms described in previous issues of this summary:

 

"Strong seismicity is still possible within 10-15 degrees from the geomagnetic equator and at high auroral latitudes around September 18-21." (September 15-17, 2017)

 

The earthquake in the Southern Mid-Atlantic is the strongest within about 200 km  of that epicenter since a similar M 5.7 on September 26, 2002 - the only such event in at least 25 years.  It was not reported felt in this epicentral area. Forecast 110624 had expected this event in this region was likely around September 21.

 

O: 18SEP2017 05:28:03  18.5S   12.8W Mw=5.7  EMSC   SOUTHERN MID-ATLANTIC RIDGE  

P: 21SEP2017 110624    20.0S   12.0W 4.0-5.4 BBAAA  So. Mid-Atlantic Ridge     

 

The event of M 5.7 in New Britain was also not reported felt. It occurred within  about 10 degrees of the geomagnetic equator and was probably promoted by geomagnetic effects. The last earthquake in the region within about 200 km of this epicenter occurred on July 7, 2017 (M 5.7). The last of stronger magnitude was an M 6.3 on March 5, 2017. Forecast 110395 had expected this event within about 25 km of the epicenter was likely around September 17.

 

O: 17SEP2017 14:26:09   6.3S  148.9E Mw=5.7  EMSC   NEW BRITAIN REGION, P.N.G.   

P: 17SEP2017 110395     6.0S  149.0E 4.0-5.4 AAAAA  New Ireland                

 

Seismicity in the Tonga region near the geomagnetic equator was also active today. The largest of these events, an M 5.4 had been forecast in #110609 to occur within about 150 km of this epicenter in mid-September.

 

O: 17SEP2017 14:50:02  16.7S  173.6W mb=5.4  EMSC   TONGA                        

P: 15SEP2017 110609    17.0S  172.0W 4.0-5.4 AABAA  Tonga Islands              

 

One of the stronger felt earthquakes today was an M 4.9 near the east coast of Honshu, Japan. This event occurred as Typhoon Talim passed over the Honshu region. This leads to an atmospheric unloading event with low pressures over the overriding plate, which can encourage seismicity. This had been noted in the previous issue of this summary as:

 

"A moderate earthquake in Japan is likely as this storm passes through the region. The area of Honshu and Hokkaido and the Kuril Islands is under a seismic advisory through September 19." (September 16-17, 2017)

 

The last earthquake within about 100 km of this epicenter occurred on July 20, 2017 with a new moon. This is in the shadow of the M 9+ quake of March 11, 2011 and should be relative quiet for many years as the stress has been largely removed with that quake. Forecast 110482 had expected this event around September 14. This epicenter is at 105 degrees (a distance at which triggering is likely) from the great Mexican earthquake and was probably promoted from that source.

 

O: 17SEP2017 09:25:00  37.2N  141.4E mb=4.9  EMSC   NEAR EAST COAST OF HONSHU, JAP

P: 14SEP2017 110482    38.0N  141.0E 4.0-5.7 BAAAA  Off East Coast Honshu      

 

The aftershock sequence in Chiapas and Oaxaca, Mexico continued to slowly relax today. While at least 20 events of M>=4 were recorded, there were none of M>=5. This may change in the next several days as tidal stresses increase with the new moon and the geomagnetic field becomes more organized.

 

O: 17SEP2017 09:35:55  15.0N   94.2W ML=4.0  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 18SEP2017 01:39:43  15.0N   94.3W ML=4.2  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 17SEP2017 10:02:53  15.3N   94.8W ML=4.0  EMSC   OFF COAST OF OAXACA, MEXICO

O: 18SEP2017 00:31:37  15.4N   94.7W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 17SEP2017 17:53:03  15.4N   94.9W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 17SEP2017 16:29:26  15.5N   93.5W ML=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 18SEP2017 01:50:09  15.5N   94.0W mb=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 18SEP2017 06:04:24  15.5N   94.1W ML=4.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 17SEP2017 13:12:14  15.6N   94.2W mb=4.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 17SEP2017 09:06:54  15.6N   95.2W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 17SEP2017 16:54:42  15.6N   95.3W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 17SEP2017 09:25:50  15.8N   94.4W ML=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 17SEP2017 17:33:48  15.8N   95.0W ML=4.6  EMSC   OFFSHORE OAXACA, MEXICO

O: 18SEP2017 00:19:34  15.8N   95.2W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 18SEP2017 02:24:03  15.8N   95.2W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 17SEP2017 09:21:46  15.9N   94.9W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 17SEP2017 19:52:35  15.9N   95.2W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 17SEP2017 18:40:42  16.1N   95.0W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 17SEP2017 06:07:58  16.1N   95.0W mb=4.8  EMSC   OFFSHORE OAXACA, MEXICO

O: 17SEP2017 06:03:32  16.1N   95.1W mb=4.5  EMSC   OFFSHORE OAXACA, MEXICO

 

With the new moon approaching on September 20 seismicity along the solar eclipse path of the previous new moon is likely to be active. The largest earthquakes in the U.S. or Canada, outside Alaska occurred in this limited zone with  an M 3.6 in southern Idaho and an M 3.1 in Yellowstone National Park. The earthquake in Yellowstone is the strongest since an M 3.2 on August 21 accompanied the previous new moon and eclipse. Today's epicenter is near Old Faithful but this event is probably too small to affect plumbing and timing at that classic geyser. Forecasts 110553 and 110832 had expected this activity between September 16 and 22.

 

NEIC reported this earthquake of M 3.1 in Yellowstone, Wyoming was felt with intensity II-III in the area(s) of Yellowstone National Park, Wyoming.

 

O: 17SEP2017 05:38:44  44.3N  110.8W ML=3.1  EMSC   YELLOWSTONE NAT. PARK, WYOMING

P: 16SEP2017 110553    44.2N  110.3W 2.0-4.1 AAAAA  Yellowstone/Wyoming        

P: 22SEP2017 110832    44.6N  110.8W 2.0-4.0 BAAAA  Yellowstone/Wyoming        

 

The largest earthquake in the U.S. or Canada today was an M 3.6 aftershock in Southern Idaho. Since the mainshock in this area on September 2, 2017 (M 5.3) aftershocks have reached the M>=3.6 level on four of the past five days. This has been a very active aftershock sequence. Today's event had been forecast in 110552 to occur around September 20 with magnitude up to M 4.1. Like Yellowstone, it is likely that earthquakes in this area are modulated by groundwater which rises or falls with increasing tidal stresses.

 

NEIC reported this earthquake of M 3.6 in Southern Idaho was felt with intensity II-III in the area(s) of Grace, Soda Springs and Rexburg, Idaho.

 

O: 17SEP2017 15:59:58  42.5N  111.4W ML=2.8  EMSC   SOUTHERN IDAHO

O: 17SEP2017 19:28:47  42.6N  111.4W ML=2.5  EMSC   SOUTHERN IDAHO

O: 17SEP2017 07:09:41  42.6N  111.4W ML=2.6  EMSC   SOUTHERN IDAHO

O: 17SEP2017 07:40:47  42.6N  111.5W ML=2.4  EMSC   SOUTHERN IDAHO

O: 18SEP2017 04:49:09  42.6N  111.5W Mw=3.6  EMSC   SOUTHERN IDAHO

O: 17SEP2017 16:11:04  42.5N  111.4W ML=2.6  EMSC   SOUTHERN IDAHO               

P: 20SEP2017 110552    43.0N  111.5W 2.0-4.1 BAAAA  Yellowstone/Wyoming        

 

MODERATE AFTERSHOCK IN SOUTHEAST ALASKA

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 16, 2017

 

A moderate M 5.1 earthquake shook the area of Southeastern Alaska today. It was  reported by NEIC to have been felt with intensity II-III in Alaska at Skagway, Haines, Gustavus, Elfin Cove, Juneau, Hoonah, Douglas, Petersburg, Gakona, Anchorage and Soldotna and in the Canadian Yukon at Whitehorse.  This is the strongest aftershock of the M 6.2 which hit the area on May 1 since that date (that was a double event with two earthquakes of M 6.2 and a third of M 5.2 on May 1, 2017). Earthquakes Canada reported this event was felt, without damages, in Whitehorse, Yukon, Canada. Forecast 110580 had expected a moderate aftershock within about 25 km of this epicenter was likely around September 20.

 

O: 16SEP2017 23:38:01  59.9N  136.7W ML=5.0  EMSC   SOUTHEASTERN ALASKA          

O: 16SEP2017 23:38:03  59.9N  136.7W mw=5.1  ANSS   WNW of Skagway Alaska

P: 20SEP2017 110580    60.0N  137.0W 3.2-5.0 BAAAA  Central Alaska             

 

The earthquake in Southeastern Alaska occurred 11-12 minutes after an M 3.9 in Oklahoma (s-wave travel time for the 35 degrees separating these two epicenters). The M 3.9 was the largest earthquake in the U.S. or Canada outside Alaska today. NEIC reported it was felt with maximum intensity IV in Oklahoma at Cushing, Wellston, Arcadia, Choctaw, and Edmond and in general with intensity II-III within about 100 km of the epicenter. Intensity II-III was felt in Oklahoma at Stroud, Agra, Drumright, Chandler, Tryon, Coyle, Luther, Guthrie, Newalla and Oklahoma City among other communities in Oklahoma. This is the strongest earthquake in Oklahoma since an M 3.9 on September 8, in association with the great Mexican quake of that date. Prior to that the largest was an M 4.2 on August 2, 2017. Forecast 110501 had expected today's event within about 25 km of the epicenter was likely around September 17.

 

O: 16SEP2017 23:26:59  35.9N   96.7W mb=3.9  EMSC   OKLAHOMA                     

O: 16SEP2017 23:26:59  35.9N   96.7W mb=3.9  ANSS   NNW of Stroud Oklahoma

P: 17SEP2017 110501    36.0N   97.0W 2.0-4.1 AAAAA  Southern Plains            

 

The strongest earthquake in the world today was an M 5.5 in the area of Kamchatka. It was reported felt in Kamchatka at Mohovaja and Jelizovo within about 100 km from the epicenter. This is near the antipode of the similar-sized event in the South Sandwich Islands which occurred yesterday and is part of a series of moderate to moderately strong earthquakes currently striking high latitudes. This activity is likely promoted by the strong geomagnetic storm currently in progress as noted in the previous summary:

 

"The geomagnetic field was at minor storm conditions today.  The AP level was 36. High latitude geomagnetic field saw major storms with AP at 51. Strong seismicity is still possible within 10-15 degrees from the geomagnetic equator and at high auroral latitudes around September 18-21." (September 16, 2017)

 

The earthquake in Kamchatka is the strongest in that region since an M 6.6 about 500 km northeast of this epicenter on March 29, 2017. There have been no larger quakes within about 250 km of this epicenter during 2017. The last earthquake of M>=5.5 within the 250 km radius of this epicenter was an M 5.5 on November 25, 2016 and prior to that an M 5.7 on April 14, 2016. The area was shaken by an M 7.2 on January 30, 2016. Forecast 110564 had expected this event within about 100 km of the epicenter around September 14.

 

O: 16SEP2017 21:00:57  53.0N  159.7E Mw=5.5  EMSC   OFF EAST COAST OF KAMCHATKA  

P: 14SEP2017 110564    54.0N  159.0E 4.0-5.7 AAAAA  Kamchatka                  

 

Moderate aftershocks also continued in the regions of Chiapas and Oaxaca, Mexico today. The strongest of these were of M 5.3 and 5.0. Activity at the M 4-5 range was higher than yesterday however. Forecast 110410 and 110409 expected this activity between September 14 and 18.

 

O: 16SEP2017 10:18:27  14.9N   94.3W ML=4.5  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 16SEP2017 11:23:24  15.0N   94.1W mb=4.9  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 16SEP2017 10:38:07  15.1N   94.2W mb=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 16SEP2017 21:32:26  15.2N   94.4W mb=4.1  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 16SEP2017 19:35:29  15.3N   94.5W Mw=5.0  EMSC   OFF COAST OF OAXACA, MEXICO

O: 16SEP2017 12:25:20  15.4N   94.7W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 16SEP2017 23:10:41  15.5N   94.2W mb=4.5  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 16SEP2017 18:58:03  15.6N   94.7W mb=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 16SEP2017 23:41:31  15.6N   95.2W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 16SEP2017 22:28:47  15.6N   95.2W ML=4.6  EMSC   OFFSHORE OAXACA, MEXICO

O: 16SEP2017 16:00:13  15.7N   95.2W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 16SEP2017 14:36:57  15.7N   95.2W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 16SEP2017 17:46:07  15.7N   95.6W mb=4.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 16SEP2017 17:07:16  16.1N   95.1W mb=4.5  EMSC   OFFSHORE OAXACA, MEXICO

P: 14SEP2017 110410    17.0N   95.0W 3.5-5.5 AAAAA  Chiapas, Mexico             

P: 18SEP2017 110409    14.0N   94.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

 

EXTENSIONAL AREAS ACTIVE

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 15, 2017

 

The most active areas of the world today were extensional regimes including ocean ridges and the East African Rift Valley. These earthquakes tend to occur when land motions are horizontal. Horizontal motions often are encouraged by strong tropical storms such as have been occurring in the past several weeks.

 

An earthquake of M 5.0 occurred on the East African Rift in the D.R. Congo. NEIC

reported it was felt with intensity V in Cyangugu, Rwanda and II in Kigali, Rwanda. In the Congo it was felt with intensity IV in Goma and III in Bukavu. The last  earthquake within about 250 km of this epicenter in the Congo with M>=5.0 was an M 5.8 on August 7, 2015. Today's event was likely promoted by geomagnetic effects as it lies near the geomagnetic equator. Forecast 110393 had expected this event within about 50 km of the epicenter  to occur around September 13.

 

 

O: 15SEP2017 17:45:46   2.8S   28.8E Mw=4.9  EMSC   LAC KIVU REGION, CONGO       

O: 15SEP2017 17:45:47   2.7S   28.8E mb=5.0  ANSS   Republic of the Congo

P: 13SEP2017 110393     2.0S   29.0E 3.0-4.6 AAAAA  Lake Victoria area         

 

The strongest earthquake of the day was an M 5.6 in the South Sandwich Islands. It was not reported felt in this area. This is the strongest earthquake in the South Sandwich Islands since an M 6.0 on September 4, 2017. An M 6.4 also occurred on May 10, 2017 with aftershocks of M 5.7 on May 11 and 30. Forecast 110642 had expected this event was likely within about 50 km of this epicenter around September 18.

 

O: 15SEP2017 18:48:07  55.4S   28.4W Mw=5.6  EMSC   SOUTH SANDWICH ISLANDS REGION

P: 18SEP2017 110642    55.0S   28.0W 4.0-6.0 BAAAA  So. Sandwich Islands       

 

A pair of ocean ridge events of M 4.7 each also occurred on the Western Indian-Antarctic Ridge today. This and other ocean ridge activity today was probably promoted by the strong geomagnetic storm last week. These events are at nearly the opposite longitude and at the same high southern latitude as the events in the South Sandwich Islands. The only moderate quake within about 500 km of this epicenter during 2017 was an M 4.6 on January 22, 2017. Today's activity in this region had not been forecast.

 

O: 15SEP2017 15:55:10  51.9S  140.4E mb=4.7  EMSC   WESTERN INDIAN-ANTARCTIC RIDGE

O: 15SEP2017 15:47:02  52.0S  139.6E mb=4.7  EMSC   WESTERN INDIAN-ANTARCTIC RIDGE

 

Moderate earthquakes of M 4.5 and M 4.6 occurred in Guerrero, Mexico today as Hurricane Max made landfall. These events were reported felt with intensity II-III in Acapulco and San Marcos, Guerrero. This summary had expected it as:

 

"TS Max continued today south  of central Mexico with winds up to 75 kts. It is expected to track to the north making landfall near Acapulco, Mexico early on September 15. As it reaches areas north of the subduction zone, atmospheric unloading could promote a moderate to strong earthquake near the eye (about 16-17N 99-100W). This area is under seismic watch for the next three days through September 18." (September 14-15, 2017)

 

Forecast 110429 had expected this activity around September 12 within about  25 km of this epicenter. The last earthquake within about 100 km of this activity was an M 5.2 on August 18, 2017.

 

O: 16SEP2017 02:22:30  16.7N  100.0W ML=4.6  EMSC   OFFSHORE GUERRERO, MEXICO

O: 16SEP2017 02:22:30  16.6N  100.0W ML=4.6  UNAM  l SUROESTE de ACAPULCO, GRO *: 16.

O: 16SEP2017 02:27:08  16.8N  100.1W ML=4.5  UNAM  l SUR de COYUCA DE BENITEZ, GRO *:

O: 16SEP2017 05:46:12  16.8N  100.1W ML=4.2  EMSC   OFFSHORE GUERRERO, MEXICO

O: 16SEP2017 02:27:08  16.8N  100.1W ML=4.5  EMSC   OFFSHORE GUERRERO, MEXICO    

P: 12SEP2017 110429    17.0N  100.0W 3.5-5.2 BAAAA  Oaxaca, Mexico             

 

The Caribbean also continued at active conditions today. An M 4.6 in Martinique was  felt with maximum intensity IV in Le Lamentin, Fort-de-France, Martinique and with intensity II-III in Martinique at Schoelcher, Les Trois-Ilets, Saint-Pierre, Cap Estate and Castries. The only earthquake in Martinique of larger magnitude this years was an M 5.7 on February 3, 2017. This is probably and aftershock of that event. Forecast 110416 had expected today's event within about 50 km of the epicenter to occur around September 12.

 

O: 15SEP2017 10:58:31  15.0N   60.6W Mw=4.6  EMSC   MARTINIQUE REGION, WINDWARD IS

O: 15SEP2017 10:58:31  15.0N   60.6W mw=4.6  ANSS   Petite Riviere Salee Martinique

P: 12SEP2017 110416    15.0N   60.0W 3.0-5.2 BAAAA  Leeward Islands            

 

Also in the Caribbean, Hurricane Irma struck the island of Barbuda hard on  September 5-6. With winds up to 200 kts, up to 95% of the built structure was destroyed. Survivors have now all been evacuated. For the first time in more than 300 years there are no people living in Barbuda. An M 4.4 earthquake in Barbuda today was therefore not reported felt as there was no one there to feel it. This earthquake was probably promoted by residual stresses from Hurricane Irma. An earthquake of M 5.6 on April 17, 2017 was preceded by an M 4.5 foreshock on April 17. These are the only quakes of M>=4.4 in Barbuda during 2017. Forecast 110417 expected today's activity within about 100 km of this epicenter was likely around September 18.

 

O: 16SEP2017 05:43:32  17.5N   60.9W mb=4.4  EMSC   ANTIGUA AND BARBUDA REGION   

P: 18SEP2017 110417    18.0N   62.0W 3.0-5.3 AAAAA  Leeward Islands            

 

A series of minor earthquakes under a sacred volcano in North Korea followed the nuclear tests near there last month. More than sanctions from other nations, this may give North Korea pause in their nuclear testing. China has restricted access to the area fearing a triggered volcanic eruption may occur.

 

The strongest earthquakes in the U.S. or Canada today was an M 4.2 in northern Hawaii and an M 4.6 in the Fox Islands, Aleutians. NEIC reported this event was felt with intensity II-III in Hawaii at Kaneohe Bay, Kailua, Kaaawa, Waimanalo, Kaneohe, Honolulu, Hauula, Laie, Aiea, Pearl City, Mililani, Haleiwa, Wahiawa, Pearl Harbor, Waipahu, Mauna Loa, Waialua, Waianae, Kualapuu, Kaunakakai, Lahaina and in general within about 100 km of the epicenter. This event is well to the northwest of normal volcanic tremor which frequently shakes the region. The last earthquake of M>=4.2 within about 150 km of this epicenter in Oahu was an M 4.5 on June 21, 2013, the only such event in Hawaii in at least 25 year. Three others, including an M 4.7 on March 9, 2017 lay just outside the 150 km radius.  Forecast 110441 had expected this event in this area was likely around September 18. This epicenter is located at the sixth node (60 degrees) from the strong quake in Chiapas, Mexico, M 8.2 on September 8 and was probably promoted from that source. 

 

O: 16SEP2017 06:40:37  21.6N  157.5W ML=4.2  EMSC   OAHU REGION, HAWAII          

P: 18SEP2017 110441    20.3N  156.6W 4.0-5.6 ABAAA  Hawaii area                

 

The last earthquake of M>=4.6 in the Fox Islands occurred on September 8 with M 4.7. Forecast 110563 had expected this event within about 100  km of the epicenter around September 14.

 

O: 16SEP2017 01:34:49  52.1N  170.6W mb=4.6  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

P: 14SEP2017 110563    52.4N  169.4W 3.5-4.9 AAAAA  Fox Islands, Aleutians     

 

ANOTHER MODERATELY LARGE QUAKE ON TYPHOON TALIM'S PATH

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 14, 2017

 

The strongest earthquake in the world today was an M 5.8 in the northern Mariana Islands north of Guam. NEIC reported it was felt with intensity III in Saipan at San Roque and Garapan and in Tinian, MP. This area had been expected to see enhanced seismicity at this time because Typhoon Talim passed through the region two days ago. This  summary had expected a moderate to strong earthquake in the Northern Mariana Islands at this time - most likely associated with a strong ocean storm. This had been noted in  previous summaries as:

 

 

"Typhoon Talim continued west of the Mariana Islands today with winds up to 80 kts. It is expected to track towards Taiwan over the next two days  reaching typhoon levels around September 14. Seismicity in the Mariana and Volcano Islands and in the Northern Philippines and Taiwan is expected to increase as this storm passes through the region. A seismic watch is in effect for the areas of Guam, northern Philippines and Taiwan through September 16. An M 5.8 in the Volcano Islands today appears to have been promoted by stresses from this storm." (September 11, 2017)

 

An M 5.5 hit near this epicenter about 100 km to the east on June 9, 2017 but the last event within about 150 km of this epicenter with M>=5.8 was an M 7.7 on July 29, 2015. Today's event appears to be the strongest aftershock to date of that event.  Forecast 110426 had expected this event within about 25 km of this epicenter was likely around September 12.

 

O: 14SEP2017 17:41:34  18.7N  145.9E Mw=5.8  EMSC   PAGAN REG., N. MARIANA ISLANDS

P: 12SEP2017 110426    19.0N  146.0E 4.0-5.5 AAAAA  No. Marianas               

 

The second largest earthquake today was an M 5.2 in the Easter Island Region of the South Pacific. It was not reported felt in the area. The last earthquake within about 500 km of this epicenter in the Easter Island area was an M 4.7 on March 18, 2017. The last of M>=5.2 occurred as an M 5.4 about 250 km to the south on September 12, 2016 while the last within about 150 km was an M 5.2 on September 21, 2014, the last of a series of aftershocks of an M 6.1 on September 5, 2014.

 

This epicenter in the South Pacific is within about 300 km of being antipodal to an event of M 4.6 which occurred earlier in the day in the Iran-Pakistan border region. Antipodal pairs are more common during periods of strong  flare/geomagnetic activity, and a relation between these and the current geomagnetic storm is possible. Forecast 110622 had expected the event in the  Pacific whereas 110447 had expected Pakistan to be active in mid-September. The most recent earthquakes in this area of Pakistan of M>=4.6 occurred on July 9, 2017 (M 4.7) and March 18, 2017 (M 4.6) - both about 200 km east of today's epicenter.

  

O: 15SEP2017 01:38:19  26.8S  112.7W mb=5.2  EMSC   EASTER ISLAND REGION         

P: 13SEP2017 110622    24.0S  112.0W 4.0-5.4 ACAAA  So. East Pacific Rise      

 

O: 14SEP2017 13:17:42  27.2N   63.5E mb=4.6  EMSC   IRAN-PAKISTAN BORDER REGION  

P: 21SEP2017 110447    29.0N   68.0E 3.5-4.9 ABCAA  Pakistan                   

 

An earthquake of M 3.3 in the foothills east of San Francisco, California occurred today. NEIC reported they were felt with intensity II-III in Milpitas, San Jose, Santa Clara, Fremont, Alviso, Sunnyvale, Campbell, Mountain View, Cupertino, Menlo Park, San Mateo, San Francisco, California.

The M 3.3 followed a foreshock of M 2.6 which was felt with intensity II-III in San Jose, Milpitas, Mount Hamilton, Fremont, Pleasanton and Santa Cruz, California. The last earthquake with M>=3.3 within the San Francisco or San Jose area was an M 3.8 on April 30, 2017 and prior to that in September 13 and 28, 2016 (M 3.3, 3.5). Forecast 110460 had expected today's activity was likely around September 13 within about 25 km of these epicenters. This area often becomes active with strong solar flares and geomagnetic storms and this may have been the prime promoter for today's events. While earthquakes of M 3.2 also occurred in northern and western Texas and in Kansas and Oklahoma today, these events of M>=3.3 were the strongest in the U.S. or Canada today.

 

O: 15SEP2017 04:59:31  37.4N  121.8W md=2.8  ANSS   East Foothills California

O: 15SEP2017 01:27:18  37.4N  121.8W md=2.0  ANSS   East Foothills California

O: 15SEP2017 01:17:47  37.4N  121.8W ml=3.3  ANSS   East Foothills California

O: 14SEP2017 17:32:17  37.4N  121.8W ml=3.3  ANSS   East Foothills California

O: 14SEP2017 19:31:15  37.4N  121.8W md=2.6  ANSS   East Foothills California    

P: 13SEP2017 110460    37.7N  121.9W 2.5-4.4 AAAAA  Central California         

 

Aftershocks of the M 8.2 in Chiapas, Mexico of September 8 continued today but at a reduced level. For the first time since the mainshock no aftershocks of  M>=5 were recorded in Chiapas or Oaxaca today. Hurricane Max is making landfall to the west in Guerrero and may be locking the subduction zone preventing strong aftershocks. A moderate earthquake near Acapulco, Mexico where landfall is expected is possible, however. Forecast 110410 had expected today's activity in Chiapas.

 

O: 15SEP2017 02:45:33  15.1N   93.8W ML=4.9  UNAM  l SUROESTE de PIJIJIAPAN, CHIS *:

P: 13SEP2017 110410    16.0N   93.0W 3.5-5.3 AAAAA  Chiapas, Mexico            

P: 14SEP2017 110410    17.0N   95.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

CALIFORNIA QUIESCENCE ENDS

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 13, 2017

 

Two events of M>=3.3 shook southern California today. These are the first earthquakes of M>=3.3 in the State of California during the month of September, 2017 and the first in the past two weeks - since an M 3.5 on August 31, 2017 in the area south of the Geysers, California. The last such quiet period occurred more than five years ago. This summary has hypothesized that the motions of Hurricane Irma caused an increase in friction across faults in California, shutting down much of the regional seismicity. With Irma no longer in the picture, faults are free to slip.  An M 3.5 shook the Baja area of Southern California today. NEIC reported it was felt with intensity II-III in Imperial, El Centro, Calexico, Brawley, Winterhave, Twentynine Palms, California.

This is the strongest earthquake within about 50 km of this epicenter near

Imperial since an M 3.7 on April 29, 2017 and prior to that an M 4.0 on March 22, 2017. A strong swarm hit the area at the end of 2016. Forecast 110486 had expected today's earthquake was likely around September 14 within about 25 km of the epicenter.

 

O: 13SEP2017 23:37:25  32.8N  115.6W ML=2.2  EMSC   SOUTHERN CALIFORNIA          

O: 13SEP2017 22:21:27  32.8N  115.6W ML=3.5  EMSC   SOUTHERN CALIFORNIA          

O: 13SEP2017 22:32:17  32.9N  115.6W ML=2.0  EMSC   SOUTHERN CALIFORNIA          

P: 14SEP2017 110486    32.5N  115.7W 2.5-4.4 AAAAA  So. California             

 

An M 3.3 also was felt in the Joshua Tree region of Southern California shortly before the event near Imperial. This event was reported felt with intensity II-III in Desert Hot Springs, Joshua Tree, Rancho Mirage, Yucca Valley, Palm Springs, Palm Desert, and Landers, California.  The last earthquake of M>=3.3 in the Joshua Tree area within about 50 km of this epicenter occurred September 24, 2016 with M 3.4. Forecast 110490 had expected this event was likely around September 17.

 

O: 13SEP2017 21:59:42  34.0N  116.3W ML=3.3  EMSC   SOUTHERN CALIFORNIA          

P: 17SEP2017 110490    34.3N  116.5W 2.5-4.6 BAAAA  So. California             

 

A moderate earthquake of M 4.6 was widely felt in the region of Tokyo, Japan today. NEIC gave maximum intensity V in Fuchu, Tokyo and IV in Saitama at Soka, Wako, and Niiza and in Musashino, Tokyo. Lesser shaking of intensity II-III was reported within about 75 km of the epicenter in Kasukabe, Sayama, Koshigaya, Kawagoe, Saitama, Tokorozawa, Kawaguchi, and Warabi, Saitama; Nitta, Gunma; Naka, Ibaraki; Yokosuka, Yamato, Yokohama, Atsugi, Sagamihara, Kawasaki, Kanagawa; Inzai, Funabashi, Urayasu, Matsudo, Fussa,  Chiba;  and in Tokyo at Machida, Hachioji, Tokyo, Akishima, Musashimurayama, Komae, Chofu, Mitaka, Kokubunji and Higashimurayama.  A similar quake hit the area on September 10 with M 4.6 about 50 km to the west of today's epicenter.  The last earthquake in this area prior to September 10 of M>=4.6 was an M 4.6 on December 25, 2016. More recent activity to the east of this epicenter occurred on August 10 (M 5.1) and August 14, 2017 (M 4.8).  The event near Tokyo had been anticipated in Forecast 110481 within about 50 km of the epicenter  was likely around September 16. This event is near the 103 degree triggering distance from the great Mexican quake of September 8. More, but larger, earthquakes from the Kurils to eastern Japan may be expected in coming days.

 

O: 14SEP2017 00:27:25  35.8N  139.5E Mw=4.6  EMSC   NEAR S. COAST OF HONSHU, JAPAN

P: 16SEP2017 110481    36.0N  140.0E 4.0-5.6 AAAAA  Off East Coast Honshu      

 

 

 

An unusual M 3.1-3.2 earthquake also shook the state of West Virginia today. NEIC reported it was felt with intensity IV within about 25 km of the epicenter in West Virginia at Ballard, Greenville, Peterstown, Lindside, and in Virginia at Rich Creek. Lesser shaking of II-III was felt in West Virginia at Wayside, Forest Hill, Wolf Creek, Talcott, Pipestem, Athens, Pence Springs, Waiteville, Hinton, Union, Lerona, Sinks Grove, Nimitz, Princeton, Gap Mills, Ronceverte,  and in Virginia at Blacksburg, Pearisburg, Newport, Eggleston, Ripplemead, Glen Lyn, Pembroke. Felt reports were also made from North Carolina, Ohio, Maryland, Kentucky, and Pennsylvania. This epicenter was near the path of totality of the total eclipse of August 21. The timing of this event within minutes of local solar noon suggests tidal promotion,  This is the strongest earthquake within about 150 km of this epicenter in  West Virginia since an M 3.4 on July 18, 2016 and prior to that on March 31, 2013. It is the strongest within about 100 km of the epicenter in at least 25 years. Forecast 110199 had expected this event in this region in early September in association with the full moon.

 

O: 13SEP2017 17:33:10  37.5N   80.7W MD=3.1  EMSC   WEST VIRGINIA                

O: 13SEP2017 17:33:10  37.5N   80.7W md=3.1  ANSS   NNE of Pearisburg Virginia

P:  4SEP2017 110199    37.2N   81.9W 2.0-4.0 CAAAA  Kentucky/Tennessee/NC      

 

The strongest earthquake in the U.S. or Canada today was an M 4.2 in Southern Alaska. NEIC reported it was felt with intensity IV in Talkeetna and II-III on the Matanusk-Sustina Border, Eagle River, Wasilla, Chugiak, and Anchorage, Alaska. The last earthquake of M>=4.3 within about 100 km of this epicenter occurred on August 31, 2017 with M 4.6 and prior to that on April 29, 2017 (M 5.2). Forecast 110585 had expected this earthquake in this region was likely to occur around September 15.

 

O: 13SEP2017 07:22:18  62.9N  150.0W ML=4.2  EMSC   CENTRAL ALASKA               

P: 15SEP2017 110585    63.2N  151.4W 3.2-4.9 AAAAA  Central Alaska             

 

The strongest seismicity in the world today continued to occur as aftershocks

 of the M 8.2 Chiapas, Mexico earthquake of September 8. The strongest of today's events were M 5.2 and 5.3. They were lightly felt in the area north of the epicenter.

 

An M 4.1 in Guerrero, Mexico may point to further seismic activity along

the Mexican subduction zone.

 

TS Max formed today south  of central Mexico with winds up to 55 kts. It is expected to track to the north making landfall near Acapulco, Mexico early on September 15. As it reaches areas north of the subduction zone, atmospheric unloading could promote a moderate to strong earthquake near the eye (about 16-17N 99-100W). This area is under seismic watch for the next three days through September 18.  Today's earthquake is just north of TS Max. Forecast 110157 had expected this event was possible around September 10.

 

O: 13SEP2017 11:51:44  18.2N  101.7W ML=4.1  EMSC   GUERRERO, MEXICO             

O: 13SEP2017 11:51:44  18.1N  101.7W ML=4.1  UNAM  l NORESTE de LAS GUACAMAYAS, MICH

P: 10SEP2017 110157    19.0N  102.0W 3.5-5.1 BAAAA  Michoacan, Mexico          

 

O: 13SEP2017 17:59:33  16.3N   95.1W ML=4.7  EMSC   OAXACA, MEXICO

O: 14SEP2017 05:03:20  14.5N   93.0W mb=4.7  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 13SEP2017 11:27:12  14.8N   94.2W ML=4.2  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 13SEP2017 09:10:04  15.1N   93.7W ML=4.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 13SEP2017 09:18:22  15.1N   94.3W ML=4.2  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 13SEP2017 13:55:25  15.2N   93.6W ML=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 13SEP2017 17:53:23  15.2N   93.7W ML=4.5  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 13SEP2017 21:42:18  15.2N   93.9W mb=4.7  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 13SEP2017 09:13:06  15.3N   94.5W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 13SEP2017 09:20:46  15.3N   94.6W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 14SEP2017 00:57:19  15.3N   95.2W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 13SEP2017 08:34:08  15.3N   95.3W ML=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 14SEP2017 00:46:54  15.5N   94.7W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 13SEP2017 09:46:23  15.6N   94.5W mb=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 14SEP2017 06:06:01  15.7N   94.4W mb=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 13SEP2017 10:44:23  15.7N   94.5W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 13SEP2017 21:30:51  15.7N   95.0W mb=5.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 13SEP2017 09:57:10  15.8N   94.7W mb=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 13SEP2017 12:48:32  15.9N   93.6W mb=4.5  EMSC   CHIAPAS, MEXICO

O: 13SEP2017 16:59:23  16.0N   94.6W mb=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 13SEP2017 19:54:40  16.0N   95.1W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 13SEP2017 20:04:10  16.0N   95.1W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 14SEP2017 05:20:28  14.4N   93.1W mb=4.1  EMSC   OFFSHORE CHIAPAS, MEXICO     

P: 13SEP2017 110410    16.0N   93.0W 3.5-5.3 ABAAA  Chiapas, Mexico            

P: 14SEP2017 110410    17.0N   95.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

STRONG SWARM IN REYKJANES RIDGE, NORTH ATLANTIC

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 12, 2017

 

A strong swarm of earthquakes occurred today in the northern Mid-Atlantic in the

Reykjanes Ridge system south of Iceland. These follow earthquakes of M 5.7 on September 1 and M 5.9, the largest in the past 25 years in the region on September 10. To date, smaller aftershocks had not been recorded. Today's activity is located about 150 km north of the two mainshocks of earlier September and do no represent classical aftershocks but were probably promoted by those larger shocks. Forecast  110567 had expected this activity was likely around September 14.

 

O: 12SEP2017 21:14:19  58.1N   32.5W mb=4.6  EMSC   REYKJANES RIDGE

O: 12SEP2017 19:09:11  58.1N   32.5W mb=4.7  EMSC   REYKJANES RIDGE

O: 12SEP2017 23:10:35  58.1N   32.5W mb=4.9  EMSC   REYKJANES RIDGE

O: 12SEP2017 22:13:27  58.1N   32.6W mb=4.8  EMSC   REYKJANES RIDGE

O: 12SEP2017 21:04:06  58.1N   32.4W mb=4.9  EMSC   REYKJANES RIDGE              

P: 14SEP2017 110567    57.0N   33.0W 4.0-5.4 ABAAA  North Mid-Atlantic Ridge   

 

The aftershock sequence in the Chiapas/Oaxaca area of Mexico following the  M 8.2 of September 8 was somewhat reduced today. There were two earthquakes of M>=5 - an M 5.1 and 5.2 recorded today. Forecasts 110409, 110410 and 110428 had expected additional activity in the area around September 12-13 (forecasts published before the mainshock).

 

NEIC reported  these aftershocks in Chiapas, Mexico continued to be lightly felt today. An event of M 5.2 in Chiapas, Mexico was felt with intensity II-III in the area(s) of Tuxtla Gutierrez, Chiapas.

 

O: 13SEP2017 00:51:39  15.1N   93.7W ML=4.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 12SEP2017 15:28:24  15.1N   93.8W mb=5.1  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 13SEP2017 00:19:04  15.1N   94.4W ML=4.4  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 12SEP2017 16:58:13  15.2N   93.1W mb=4.5  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 12SEP2017 18:29:33  15.2N   94.1W mb=4.6  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 12SEP2017 18:36:08  15.3N   93.6W mb=4.4  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 13SEP2017 02:01:42  15.3N   94.4W mb=5.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 12SEP2017 07:19:26  15.3N   95.0W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 13SEP2017 05:09:34  15.4N   93.5W mb=4.5  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 12SEP2017 21:26:51  15.4N   94.9W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 13SEP2017 02:43:11  15.5N   94.2W mb=4.4  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 13SEP2017 01:16:56  15.5N   94.3W mb=4.1  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 13SEP2017 03:32:00  15.6N   95.0W ML=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 12SEP2017 20:07:34  15.7N   94.4W mb=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 12SEP2017 19:06:12  15.7N   94.6W mb=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 12SEP2017 09:20:04  15.7N   94.8W mb=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 12SEP2017 23:25:32  15.8N   94.5W ML=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 12SEP2017 15:25:19  16.0N   94.3W mb=4.3  EMSC   OFFSHORE OAXACA, MEXICO

O: 12SEP2017 11:06:18  16.2N   94.8W mb=4.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 12SEP2017 18:42:04  16.4N   95.0W mb=4.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 13SEP2017 04:05:54  15.0N   94.4W ML=4.4  EMSC   OFF COAST OF CHIAPAS, MEXICO 

P: 12SEP2017 110409    15.0N   95.0W 3.5-5.9 AAAAA  Chiapas, Mexico             

P: 12SEP2017 110428    15.0N   96.0W 3.5-5.7 AAAAA  Oaxaca, Mexico             

P: 13SEP2017 110410    16.0N   93.0W 3.5-5.3 AAAAA  Chiapas, Mexico            

 

The strongest earthquake in the U.S. or Canada today was an M 4.3 in southern

Alaska. The last earthquake of M>=4.3 within about 100 km of this epicenter occurred on August 31, 2017 with M 4.6 and prior to that on April 29, 2017 (M 5.2). Forecast 110585 had expected this earthquake in this region was likely to occur around September 15.

 

O: 13SEP2017 07:22:17  62.9N  149.9W ml=4.3  ANSS   Southern Alaska.             

P: 15SEP2017 110585    63.2N  151.4W 3.2-4.9 AAAAA  Central Alaska             

 

Seismicity in the area of southern Idaho was sharply reduced today with only three events of M 2.0-2.5. This follows a major swarm over the past three days in the area including at least four events of M>=4. Forecast 110552 had expected this activity to peak around September 12.

 

NEIC reported an earthquake of M 2.8 in Southern Idaho was felt with intensity II-III in the area(s) of Montpelier and Soda Springs, Idaho.

 

O: 12SEP2017 13:27:06  42.6N  111.4W ML=2.4  EMSC   SOUTHERN IDAHO

O: 13SEP2017 06:57:18  42.6N  111.4W ML=2.5  EMSC   SOUTHERN IDAHO

O: 12SEP2017 09:39:03  42.6N  111.5W ML=2.1  EMSC   SOUTHERN IDAHO

O: 12SEP2017 18:23:05  42.5N  111.5W ML=2.8  EMSC   SOUTHERN IDAHO               

P: 12SEP2017 110552    43.2N  111.0W 2.0-4.0 AAAAA  Yellowstone/Wyoming        

 

A pair of moderate earthquakes occurred in the southern Caribbean area today. These occurred in the Barbados region, Windward Islands and in the Zulia area of Venezuela. Together, these events remind that the southern Caribbean has  had damaging earthquakes and is vulnerable to earthquake damage. The Barbados event is the second strongest in Barbados during 2017 - after an M 4.8 about 200 km south of this on July 19. It had been expected around September 12 in forecast 110416.

 

O: 12SEP2017 16:38:30  13.9N   58.4W mb=4.6  EMSC   BARBADOS REGION, WINDWARD ISL.

P: 12SEP2017 110416    15.0N   60.0W 3.0-5.2 ABAAA  Leeward Islands            

 

The earthquake of M 4.7 in Venezuela is the strongest in the Zulia area during

2017. Forecast 110427 had expected this was likely to the east of this epicenter around September 12.

 

O: 13SEP2017 03:07:03   9.5N   73.1W mb=4.7  EMSC   ZULIA, VENEZUELA             

P: 12SEP2017 110427    10.0N   71.0W 3.5-4.9 AABAA  Northern Venezuela         

 

WAITING FOR THE OTHER SHOE TO DROP

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 11, 2017

 

Moderate-sized aftershocks also continued from Guatemala to Oaxaca, Mexico today. The strongest of these was an M 4.9 southwest of Pijijiapan, Mexico. NEIC reported it was felt with intensity II-III in Olintepeque, Guatemala City, Santa Catarina Pinula, Guatemala and at Villahermose, Tabasco, Mexico.

The toll from the mainshock has now risen to at least 96 with at least 2 million people in need of aid. The press is reporting this as the largest earthquake ever recorded in Mexico - not sure where this comes from, but larger quakes have been recorded than M 8.1 in that country. Thousands of building were destroyed during the earthquake which was probably triggered by the arrival in the earth's environment of the CME from the strongest solar flare in nearly 12 years (X9.3). A second, slightly smaller flare (X8.3) occurred yesterday and the CME from that may be due to hit earth September 12-13. Global seismicity is expected to increase with the likelihood of a major earthquake near the geomagnetic equator or at high latitudes is  possible during the next four days. Aftershocks of M>=5 are listed here, others are in the regional "AMERICA" section below.

 

NEIC reported the earthquakes of M 5.3 and M 5.6 in Eastern Mexico and Guatemala was felt with intensity IV in San Cristobal de las Casas, Chiapas and II-III in the area(s) of Villahermosa, Tabasco, Mexico and in Guatemala at Olintepeque, Quezaltenango and in Mixco. Forecasts 11410 and 110428 had expected this activity around September 12-14. These forecasts were first published prior to the great Mexican quake of September 8.

 

O: 12SEP2017 05:08:47  15.2N   93.8W Mw=5.3  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 12SEP2017 01:12:34  15.5N   94.2W Mw=5.1  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 11SEP2017 14:56:00  15.5N   94.2W mb=5.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 12SEP2017 05:08:45  15.0N   94.0W ML=5.3  UNAM  al SUROESTE de PIJIJIAPAN, CHIS *:

O: 12SEP2017 01:12:31  15.0N   94.5W ML=5.2  UNAM  al SUROESTE de TONALA, CHIS *: 15.

O: 11SEP2017 21:09:13  15.0N   94.2W ML=5.6  UNAM  al SUROESTE de TONALA, CHIS *: 15.

O: 11SEP2017 14:55:58  15.2N   94.6W ML=5.2  UNAM  al SURESTE de SALINA CRUZ, OAX *:

O: 11SEP2017 21:09:13  15.0N   93.8W Mw=5.4  EMSC   OFFSHORE CHIAPAS, MEXICO     

P: 12SEP2017 110428    15.0N   96.0W 3.5-5.7 AAAAA  Oaxaca, Mexico             

P: 13SEP2017 110410    16.0N   93.0W 3.5-5.3 AAAAA  Chiapas, Mexico            

P: 14SEP2017 110410    17.0N   95.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

The strongest earthquake of the day occurred as an M 5.7 in the Volcano Islands of southeastern Japan. The Volcano Islands about the Mariana Islands on the  north and are part of the Guam region. The previous summary had placed this area under a seismic watch for this time as follows: 

 

"A pair of moderate earthquakes also occurred in the Guam and Rota regions of the Mariana Islands today. This may have been promoted by stresses from Tropical Storm Talim which passed through the area several days ago. This summary had expected this activity as:

 

"TS Talim continued west of Guam today with winds up to 50 kts. It is expected to track towards Guam over the next four days.  It should reach typhoon levels around September 14. Seismicity in Guam and the Northern Philippines and Taiwan is expected to increase as this storm passes through the region. A seismic watch is in effect for the areas of Guam. " (September 9-10, 2017)

 

The last earthquake in the Volcano Islands of M>=5 was an M 5.2 on June 4, 2017 but today's event is the strongest in this area since an M 6.2 on August 4, 2016. 2016. Forecast 110452 had expected this event within about 150 km of this epicenter was likely in mid-September.

 

O: 11SEP2017 17:35:09  24.0N  142.4E Mw=5.7  EMSC   VOLCANO ISLANDS, JAPAN REGION

P: 19SEP2017 110452    23.0N  143.0E 4.0-5.6 CAAAA  Volcano Islands            

 

A new tropical depression - TD 21W - in the Central Philippines was accompanied today by a moderate earthquake which was widely felt.  TD 21W formed today over the central Philippines with winds up to 35 kts. It is expected to track  into South Asia by September 15. An M 4.8 occurred while the eye of TD 21W was passing through the area of central Philippines today and was probably promoted by stresses from this storm. Forecast 110418 had expected this event around September 12.

 

PHIVOCS reported this quake was felt with intensity IV in Guiuan, Easter, Samar, III in Salcedo and Lawaan, Eastern Samar and II in Tacloban and Palo, Leyte, Phlippines. NEIC reported this earthquake of M 4.8 in Central Philippines was felt with intensity V in the area(s) of Balangiga, Eastern Visayas, Philippines.

 

O: 11SEP2017 18:25:38  10.9N  126.1E MS=4.9  PHI  Felt with intensity IV

O: 11SEP2017 18:25:39  10.9N  125.9E mb=4.8  EMSC   LEYTE, PHILIPPINES           

P: 12SEP2017 110418    10.0N  125.0E 3.5-4.9 AAAAA  Luzon, Philippines         

 

A moderate aftershock of M 4.6 in southern Utah today was accompanied by a number of lightly felt aftershocks including an M 4.1 and M 4.3. The mainshock today was reported by NEIC to have been felt with maximum intensity V in Montpelier, Idaho and IV in Soda Springs, Idaho. This event was also felt with intensity II-III in Idaho at Grace, Preston, Bancroft, Franklin, Inkom, Pocatello, Swan Valley, Malad City, Idaho Falls; in Wyoming at Jackson, Etna, Thayne, Bedford, Afton, Smoot, and in Utah at Richmond. NEIC reported other aftershocks  in southern Idaho were felt with intensity II-III in the area(s) of Pocatello and Soda Springs, Idaho. Larger aftershocks were also reported felt with intensity II-III in Utah at Logan and Eagle Mountain today. Earthquakes of M>=3 today are listed here, others are in the "ROCKY MOUNTAIN" regional section below. Forecast 110552 had expected this activity around September 12. This activity is a surprisingly strong aftershock sequence following the M 5.3 on September 2 which, in turn, was located under the path of totality of the solar eclipse of August 21, 2017.

 

O: 11SEP2017 13:38:34  42.5N  111.4W ML=3.0  EMSC   SOUTHERN IDAHO

O: 11SEP2017 15:11:32  42.5N  111.4W ML=3.0  EMSC   SOUTHERN IDAHO

O: 11SEP2017 14:05:29  42.5N  111.4W ML=3.4  EMSC   SOUTHERN IDAHO

O: 11SEP2017 09:36:31  42.5N  111.4W ML=4.4  EMSC   SOUTHERN IDAHO

O: 11SEP2017 10:00:17  42.6N  111.4W ML=3.0  EMSC   SOUTHERN IDAHO

O: 11SEP2017 11:46:31  42.6N  111.4W ML=3.1  EMSC   SOUTHERN IDAHO

O: 11SEP2017 19:20:04  42.6N  111.5W ML=3.0  EMSC   SOUTHERN IDAHO

O: 11SEP2017 15:33:53  42.6N  111.5W ML=3.1  EMSC   SOUTHERN IDAHO

O: 12SEP2017 00:00:25  42.6N  111.5W ML=3.1  EMSC   SOUTHERN IDAHO

O: 11SEP2017 12:34:30  42.6N  111.5W Mw=4.1  EMSC   SOUTHERN IDAHO

O: 11SEP2017 17:31:29  42.5N  111.4W ML=2.5  EMSC   SOUTHERN IDAHO               

P: 12SEP2017 110552    43.2N  111.0W 2.0-4.0 AAAAA  Yellowstone/Wyoming        

 

In addition to the M 4.6 in Idaho today, a similar sized quake hit the Alaska Peninsula. It was not reported felt in this remote area. An M 4.3 hit the same epicenter on September 9 suggesting some stress to be relieved in a larger coming quake. The strongest quake within about 150 of this epicenter during 2017 was an M 4.9 on February 27, 2017. The last event in this region of M>=4.6 was an M 4.6 on March 24, 2017. Forecast 110286 had expected this earthquake was likely in early September.

 

O: 12SEP2017 06:43:42  55.3N  157.2W Ml=4.6  EMSC   ALASKA PENINSULA             

O: 12SEP2017 06:43:42  55.3N  157.2W ml=4.6  ANSS   Alaska Peninsula

P:  6SEP2017 110286    54.8N  158.7W 3.5-4.9 CAAAA  Alaska Peninsula           

 

The largest earthquake in the U.S. or Canada, however, occurred as an M 5.1-5.4

in the western Andreanof Islands of Alaska. This is another remote area where earthquakes, event large events, are seldom reported felt. This appears to be  a regional aftershock of an M 6.2 event which hit about 50 km northwest of this on May 8, 2017, the strongest aftershock in the region since May 10, 2017. Forecast 110288 had expected this event was likely around September 8.

 

O: 11SEP2017 21:52:08  51.5N  178.3W Mw=5.1  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

O: 11SEP2017 21:52:08  51.5N  178.4W Mw=5.4  NEIC   ANDREANOF ISLANDS, ALEUTIAN IS

P:  8SEP2017 110288    51.7N  179.7W 3.5-5.3 BAAAA  Andreanoff Isls, Aleutians 

 

An unusually large earthquake of M 5.0 also hit the region of northern Greece today.  NEIC reported this earthquake of M 5.0 in Northern Greece was felt with intensity II-III in the area(s) of Northern Greece at Karditsa and Diminion, Magnisia, Greece.  The last earthquake within about 100 km of this epicenter in Greece with M>=5 was an M 5.5 on October 15, 2016 (and aftershocks to October 16).  Forecast 110205 had expected this event within about 100 km of the epicenter was likely around September 9. This appears to be part of the seismic ping-pong between the area of Greece and Western Turkey and the Guatemala-eastern Mexico area which this summary has been following since the Guatemala events of mid-June. For example when an M 6.7 occurred southeast of today's epicenter in the Dodecanese Islands of Greece it was reported:

 

"These earthquakes (in the Dodecanese Islands) are located at 103 degrees from the strong events in Guatemala of M 6.9 of June 14 and 22. Seismic energy reflected and refracted off the core-mantle boundary following strong earthquakes concentrates at the surface at this distance and may help promote further seismicity. This activity is also at 146 degrees from the M 6.6 of southern New Zealand of July 11, a distance at which concentrated seismic energy may help promote additional seismicity. This summary has named the process of two areas triggering each other - seismic ping-pong." (July 21, 2017)

 

and when a M 6.3 in Turkey on June 13 was followed by an M 6.7 on the Chiapas-Guatemala border on June 14 it was also noted:

 

"This event in Guatemala is located at 101-102 degrees from the M 6.3 in Turkey which occurred yesterday. It is also at 103 degrees from a tidally triggered event of Vanuatu of M 5.8 which occurred about seven hours earlier. This is a distance at which seismic energy reflected and refracted off the core-mantle boundary returns in concentrated state to the surface. Seismicity subsequently often increases this distance range, probably due to the arriving energy. When an area is near rupture this can be precipitated by a large but non-major earthquake such as the event of M 6.3 in Turkey-Greece. Was the area of Chiapas-Guatemala ready for such a triggered event? This summary has been following an escalation of seismicity in Guatemala and Chiapas, Mexico over the past several days which began with the passage of Tropical Depression Calvin over these epicenters and was noted in the previous issue of this summary" (June 14, 2017) - repeated in the summary of September 8, 2017 following the great Mexican quake.

 

It should come as no surprise, then that this earthquake in Greece was near the 102 degrees (100 degrees) from the great earthquake in Mexico of September 8. Forecast 110205 expected this activity was likely in northern Greece around September 9.

 

O: 11SEP2017 16:20:15  39.1N   21.5E mb=5.0  EMSC   GREECE                       

O: 11SEP2017 16:20:15  39.2N   21.6E mb=5.0  ANSS   WSW of Neochorion Greece

P:  9SEP2017 110205    39.0N   20.0E 3.0-4.8 AABAA  No. Greece                 

 

X8.3 SOLAR FLARE AFFECTS SEISMICITY

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 10, 2017

 

The strongest earthquake in the world today was an M 5.9 in the Reykjanes Ridge south  of Iceland. This is a remote area and this earthquake was not reported felt. This epicenter was near local solar noon when the X8.3 solar flare occurred several hours earlier. Solar Flare effects (SFE) from that event probably helped promote a larger magnitude for this earthquake than typical. The largest events within about 200 km of this epicenter in the past 25 years have been  of M 5.5-5.7, the last of which was an M 5.5 on October 6, 2011. The other event in the region of M 5.7 occurred on October 6 and 7, 2002. This epicenter is at the sixth node (60 degrees) from the great earthquake  in Chiapas, Mexico and was probably promoted from that source. Conditions  on October 6, 2011 (Hurricane Ophelia hit Virginia two days earlier) were similar to those in place today as noted in the summary from that date:

 

"The Reykjanes Ridge was at solar noon when a strong geomagnetic storm hit with Kp up to 8 and AP 20 for the day. This is the latitude and longitude which is most likely to be affected by sudden commencement geomagnetic storms such as this. At the same time two C-class solar flares occurred and probably added to  the triggering effects of the geomagnetic storm. The area was also under stress from the Post Tropical cyclone Ophelia which passed near the epicenters of these events late yesterday and early today. The combination of these triggering stresses probably forced these earthquakes at this time." (October 6-7, 2011)

 

Today's event on the Northern Mid-Atlantic Ridge had been forecast to occur around September 14 within about 50 km of this epicenter.

 

O: 10SEP2017 21:40:21  57.2N   33.6W Mw=5.9  EMSC   REYKJANES RIDGE              

P: 14SEP2017 110567    57.0N   33.0W 4.0-5.4 BAAAA  North Mid-Atlantic Ridge   

 

The CME from the X9.3 flare of September 6 triggered the great M 8.2 earthquake in Chiapas, Mexico of September 8. The flare of X8.3 today and its CME, likely to reach the earth environment around September 13-14 could also trigger a strong earthquake, depending upon when it arrives and the geomagnetic storm initiates. SWPC expects this could be as early as September 13.

 

An earthquake of M 5.5 also occurred today in Hokkaido, Japan. This event was reported felt with intensity II-III in Hokkaido at Tomakomai and Sapporo and in Aomori at Misawa and Kizukuri, Japan.  This area, which is expected to see a large quake in the next week, is at 102-103 degrees from the great Chiapas earthquake of September 9 (M 8.2). This was reported in this summary in the previous issue when a smaller foreshock occurred in Hokkaido as:

 

"Far-distance triggering from Chiapas today apparently included an M 4.6 in the Sea of Japan at 103 degrees from the Chiapas epicenter. Further activity in the Hokkaido area of M>=5 may be expected in the next several days." (September 9-10, 2017)

 

Other area at 103 degrees from Chiapas include Central New Zealand and western Turkey and the mid-east. These regions may expect to see a strong earthquake in the next month.

 

A second event in Japan of M 4.6 occurred west of Tokyo. It was reported widely felt in the Tokyo area including with intensity II-IV at Akishima, Sagamihara, Higashimurayama, Machida, Tama, Ebina, Yamato, Ayase, Komai, Musashino, Yokohama, Kawasaki, Kawaguchi, and Tokyo. The last earthquake in this area of M>=4.6 was an M 4.6 on December 25, 2016. More recent activity to the east of this epicenter occurred on August 10 (M 5.1) and August 14, 2017 (M 4.8). This earthquake occurred near the maximum of the X8.3 solar flare today, the second strongest in more than two years, and was near local solar midnight when the flare occurred. It is likely that it was promoted by Solar Flare Effects.

 

The event near Tokyo had been anticipated in Forecast 110481 within about 100  km of that epicenter while the Hokkaido event had been expected around September 7. The only earthquake during 2007 of larger magnitude then M 5.5 in Hokkaido, Japan was an M 5.7 on March 7, 2007.

 

O: 10SEP2017 15:51:08  35.7N  139.1E mb=4.6  EMSC   NEAR S. COAST OF HONSHU, JAPAN

P: 16SEP2017 110481    36.0N  140.0E 4.0-5.6 CAAAA  Off East Coast Honshu      

 

O: 10SEP2017 08:44:24  41.8N  142.8E Mw=5.5  EMSC   HOKKAIDO, JAPAN REGION       

P:  7SEP2017 110252    43.0N  143.0E 3.5-5.6 BBAAA  Hokkaido, Japan            

 

The strongest earthquakes in the U.S. or Canada today were a pair of moderate M 4.7 and 4.6 aftershock in Southern Idaho.  This is the strongest aftershock of the M 5.3 which hit the region on September 2 since two events of M 4.7 and 4.8 on September 3. The timing of this event, simultaneous with landfall of Hurricane Irma in Southern Florida suggests a promotional aspect to that storm for this earthquake. NEIC reported the M 4.7 was felt with intensity IV in Soda Springs, Montpelier, Lava Hot Springs, and Grace, Idaho and along with the M 4.6 with intensity II-III in Idaho at Soda Springs, Grace, Montpelier, Paris, Preston, Lava Hot Springs, Saint Charles, Firth, Pocatello, Malad City, Idaho Falls, and Rexburg; in Wyoming at Afton, Bedford, Thayne, Etna, and Cora and in Utah at Richmond, Portage, and Farmington.  A number of light aftershocks of M 3-4 were also felt, mostly in the Soda Springs area of Idaho. Only events of M>=4 are listed here, the more complete list is in the "ROCKY MOUNTAIN" regional listing below. Forecasts 110283 and 110552 had expected this activity

around September 8-12.

 

O: 10SEP2017 19:05:13  42.6N  111.4W ML=4.2  EMSC   SOUTHERN IDAHO

O: 10SEP2017 11:12:40  42.6N  111.4W Mw=4.6  EMSC   SOUTHERN IDAHO

O: 10SEP2017 09:47:12  42.5N  111.3W mb=4.8  EMSC   SOUTHERN IDAHO               

P:  8SEP2017 110283    43.0N  111.5W 2.0-4.1 AAAAA  Yellowstone/Wyoming        

P: 12SEP2017 110552    43.2N  111.0W 2.0-4.0 AAAAA  Yellowstone/Wyoming        

 

An M 3.8 earthquake was also felt in Southern Colorado today. This series began in early September 2001 and has continued off-and-on since that time. The cause is probably injection well technology, but this is not certain. Larger events in the Trinidad, Colorado area often occur in August or September of the year. Today's event was reported felt with intensity II-III in Weston and Trinidad, Colorado. A slightly smaller event hit the same area on September 8, 2017 with M 3.7. The last earthquake of larger magnitude then M 3.8 in the area was an M 3.9 on August 23, 2016 and an M 3.9 on August 20, 2015. An M 4.0 occurred on February 6, 2016. Forecast 110465 had expected this event within about 20 km of the epicenter was likely in mid-September.

 

O: 10SEP2017 08:34:41  37.0N  105.0W ML=3.8  EMSC   COLORADO                     

P: 15SEP2017 110465    37.0N  105.2W 2.0-4.1 BAAAA  Colorado area              

 

An earthquake of M 3.8 in northern Italy also followed the X8.3 solar flare today.  EMSC reported this earthquake of M 3.8 in Northern Italy was felt with intensity II-III in the area(s) of Ponte dell'Olio, Ligagnano Val D'arda, Piacenza, and Pavia, Italy among others.  A similar event in northern Italy accompanied the X9.3 flare of September 6 as noted at the time in this summary:

 

"While the most likely promoted seismicity from the flare will occur around September 10-12, an unusual earthquake of M 3.8 in northern Italy accompanied the X9.3 flare. It was within minutes of local solar noon at the time of flare 7340 (X9.3) and SFE and/or tidal stresses were probably promotional factors to the timing of this event. The earthquake was felt with light to moderate intensity in Italy at Valcozzena an Pera according to EMSC. Several light aftershocks were also felt in the region. The last earthquake within about 100 km of this epicenter in northern Italy with M>=3.8 was an M 4.5 on June 9, 2012. The timing and rarity of this event suggest it was triggered by the X9.3 solar flare as the sun was directly overhead at the time." (September 6-7, 2017)

 

Forecast 110521 had expected a moderate earthquake in this region of northern

Italy was likely around September 12 but the flare probably brought this earlier in time.

 

O: 10SEP2017 18:00:54  44.8N    9.7E ML=3.8  EMSC   NORTHERN ITALY               

P: 12SEP2017 110521    44.0N   11.0E 3.0-5.3 AAAAA  Italy                      

 

The most active areas of the world today continued the aftershock sequence

in Southern Idaho and that of the great quake of September 7 (M 8.2) in Chiapas, Mexico. Earthquakes in eastern Mexico included several aftershocks of M>=5 but these were not widely felt. Other earthquakes of M<5.0 are listed under the "AMERICA" regional listing below. A second epicenter was also active in the Oaxaca, Mexico area - this about 400 km to the west of the Chiapas series. This is near an epicenter which was active hours before the M 8.2 and may precede  a larger regional event. Additional aftershocks are listed under the "AMERICA" section below. Forecast 110409 had expected the activity in Chiapas was likely around September 12. Forecasts 110164 and 110429 had expected the activity near 99 West longitude in Oaxaca between September 6 and 12.

 

O: 10SEP2017 15:28:54  15.2N   94.5W mb=5.0  EMSC   OFF COAST OF CHIAPAS, MEXICO

O: 10SEP2017 08:39:39  15.8N   94.4W mb=5.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 10SEP2017 23:45:46  14.2N   93.6W mb=4.3  EMSC   OFF COAST OF CHIAPAS, MEXICO 

P: 12SEP2017 110409    15.0N   95.0W 3.5-5.9 AAAAA  Chiapas, Mexico            

 

NEIC reported the earthquake of M 4.6 in Oaxaca, Mexico was felt with intensity II-III in the area(s) of Puerto Escondido, Oaxaca, Mexico. An M 4.5 in the same area was felt earlier in the day at Mexico City and Puerto Escondido, Mexico.

 

O: 10SEP2017 12:00:29  15.9N   98.5W mb=4.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 10SEP2017 13:25:49  15.6N   98.9W ML=4.1  UNAM  al SUROESTE de PINOTEPA NACIONAL,

O: 10SEP2017 13:25:53  15.7N   98.7W mb=4.3  EMSC   OFFSHORE OAXACA, MEXICO      

P:  6SEP2017 110163    16.0N   98.0W 3.5-5.1 AAAAA  Oaxaca, Mexico             

P: 12SEP2017 110429    17.0N   99.0W 3.5-5.3 ABAAA  Oaxaca, Mexico             

 

A pair of moderate earthquakes also occurred in the Guam and Rota regions of the Mariana Islands today. This may have been promoted by stresses from Tropical Storm Talim which passed through the area several days ago. This summary had expected this activity as:

 

"TS Talim continued west of Guam today with winds up to 50 kts. It is expected to track towards Guam over the next four days.  It should reach typhoon levels around September 14. Seismicity in Guam and the Northern Philippines and Taiwan is expected to increase as this storm passes through the region. A seismic watch is in effect for the areas of Guam. " (September 9-10, 2017)

 

Forecasts 110166 and 110433 had expected these events in mid-September.

 

O: 11SEP2017 01:32:09  13.0N  143.5E mb=4.6  EMSC   GUAM REGION                  

P:  9SEP2017 110166    13.0N  143.0E 4.0-5.4 AAAAA  So. Marianas/Guam          

 

O: 10SEP2017 14:59:05  14.1N  146.8E mb=4.9  EMSC   ROTA REGION, N. MARIANA ISLAND

P: 15SEP2017 110433    14.0N  145.0E 4.0-5.4 BABAA  So. Marianas/Guam          

 

HURRICANE IRMA LANDFALL NEAR TAMPA, FLORIDA UNLIKELY TO BE MAJOR SEISMIC PROMOTER

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 9, 2017

 

A moderately strong aftershock in Chiapas and Oaxaca, Mexico of M 5.7 occurred early on September 10 (UT). At the same time Hurricane Irma was beginning to be felt on the coasts of Florida. Irma is a large low pressure system which allows the upper plate to rise with respect to the lower tectonic plate in  the North American subduction zone in eastern Mexico. This will encourage stronger aftershocks in the area in the next several days, as in this case. However, as Irma moved west seismicity in California has virtually ceased at magnitudes M>=2.5, expected as this pushes North America to the west and increases friction across strike-slip faults in California, reducing seismicity. As Irma turns to the north, this will change and seismicity should return to normal in  California in the next two days with the possibility of a moderate earthquake (M>4) along strike-slip fault in that region. Hurricane Irma is expected to make landfall near Tampa, Florida later today as a category 4 (major) hurricane, the first to hit this area in more than  a century. The last category 3 hurricane in the area occurred on October 20, 1921 and is known as the "Tampa Bay Hurricane". A hurricane on September 23-25, 1848 also hit the Tampa Bay area destroying much of the built environment. It headed across the Florida peninsula causing damage on the east coast around September 26. Earthquake records from the time are scattered and no evidence suggests major triggering from this event. An earthquake in the Wellington, New Zealand area of M>7 occurred a month later but cannot be attributed to promotion from this hurricane. Both of these began south of Florida and did not take the current path. Tampa Bay is considered to be the most vulnerable area in the U.S. to hurricane storm surge as determined in 2015 by a major study. Of the top 8 most vulnerable zones, four are in Florida - Tampa, Miami, Fort Myers and Sarasota. Each was expected to see regional damages of more than $50 billion U.S. Dollars. The current path of Irma affects each of these areas, so the cost in Dollars and human misery will be enormous. Such costs do not include related catastrophes such as the Chiapas, Mexico earthquake two days ago which has killed more  than the combined toll of Hurricane Irma to date (there will be some killed in Florida, but evacuations and mitigation plans plus ample warning will  probably keep this toll to a minimum in this area).   As Hurricane Irma makes landfall along the east coast of Florida it will push Florida to the north and east with winds and storm surges. The induced motions can affect regional seismicity but much of this motion will be absorbed by the geologic plasticity of the Florida Peninsula. Some effect on seismicity along the western North American subduction zone as noted above can be expected. But areas along the northern South American subduction zone are also likely to be affected. For example, during the landfall event of October 20, 1921, an earthquake of M 7.1 hit southern Peru and northern Chile in the Tarapaca area (also on October 20). In that hurricane no major effects were noted in the Mexican or California regions to seismicity. In general, with the exception of the northern South American subduction zone there is little evidence that landfall in the Tampa area of Florida is highly promotional to regional seismicity patterns.

 

The earthquake of M 5.7 in Chiapas, Mexico today was reported by NEIC to have been felt with intensity IV in Chiapas at Tuxtla Gutierrez and Coatepec, Mexico. Intensity II-III was felt in Nezahualcoyotl and in Mexico City. Many aftershocks of M>=4 were also recorded today. The strongest of these was an M 5.3. It was felt with intensity II in Oaxaca and Coatzacoalcos, Veracruz, Mexico. Only aftershocks of M>=5 are listed here, a more complete listing in found under the regional sets in the "AMERICA" section.

 

O: 10SEP2017 03:07:25  15.4N   94.4W Mw=5.7  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 10SEP2017 03:07:21  15.3N   94.7W ML=5.8  UNAM  al SURESTE de SALINA CRUZ, OAX *:

O: 09SEP2017 11:50:50  15.7N   94.7W mb=5.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 09SEP2017 15:30:11  15.8N   94.8W mb=5.4  EMSC   OFFSHORE OAXACA, MEXICO

 

Far-distance triggering from Chiapas today apparently included an M 4.6 in the Sea of Japan at 103 degrees from the Chiapas epicenter. Further activity in the Hokkaido area of M>=5 may be expected in the next several days. An unusual earthquake in Chukotka, Russia north of the Andreanof Islands of M 4.2 occurred at exactly 72.0 degrees (node 5) from the Chiapas epicenter.

 

The strongest earthquake in the U.S. or Canada outside Alaska today was an M 4.1 in Southern Idaho, and two of M 3.9 in this aftershock sequence. The M 4.1 was reported with intensity II-III in Idaho at Paris, Preston, Lava Hot Spring,s Saint Charles, Fish Haven, Franklin, Weston, Pocatello, Rigby, Ogden, Rock Springs; in Utah at Provo, Ogden, Tremonton, Portage, Richmond, Lewiston. It was also felt with intensity II-III in Wyoming at Thayne, Etna, and Rock Springs.

Earthquakes of M>=3 in this sequence are listed here, smaller events are in the

regional listing under "ROCKY MOUNTAIN" set.

 

NEIC reported the earthquake of M 3.1 in Southern Idaho was felt with intensity II-III in the area(s) of Soda Springs, Idaho. An earlier event of M 2.6 may have been felt in Fielding, Utah with intensity II. The earthquakes of M 3.9 were reported with intensity II in Soda Springs, Idaho and Etna, Wyoming.

 

Forecast 110283 had expected this activity was likely around September 8.

 

O: 09SEP2017 08:27:20  42.6N  111.4W ML=3.9  EMSC   SOUTHERN IDAHO

O: 09SEP2017 08:23:04  42.6N  111.4W Mw=4.1  EMSC   SOUTHERN IDAHO

O: 09SEP2017 11:52:48  42.6N  111.5W Mw=3.9  EMSC   SOUTHERN IDAHO

P:  8SEP2017 110283    43.0N  111.5W 2.0-4.1 AAAAA  Yellowstone/Wyoming        

 

The strongest earthquake in Alaska today was an M 4.3 in the Alaska Peninsula area. It was not reported felt in this remote area. This is the strongest earthquake in the Alaska Peninsula since an M 5.2 about 200 km to the southwest of this on May 28, 2017. The last of M>=4.3 within about 100 km of this epicenter was an M 4.4 on March 25, 2017. Forecast 110286 had expected this event within about 100 km of this epicenter was likely around September 6.

 

O:  9SEP2017 19:22:47  55.2N  157.1W ML=4.3  EMSC   ALASKA PENINSULA             

P:  6SEP2017 110286    54.8N  158.7W 3.5-4.9 BAAAA  Alaska Peninsula           

 

An unusual set of three light earthquakes of M 3.3, 3.3 and 3.4 occurred today off the coast of Oregon but were not reported felt. The total solar eclipse of August 21 passed directly over this epicenter and with the full moon three days ago may have helped promoted hydrothermal activity in this area off Oregon. The last similar activity in these vents off Oregon occurred on July 12 (M 4.1) and May 13, 2017 (M 4.4). No other similar activity has occurred during 2017.

Forecast 110269 had expected today's activity within about 50 km of these epicenters likely around September 11.

 

O: 10SEP2017 00:46:29  44.3N  129.3W ML=3.4  EMSC   OFF COAST OF OREGON          

O:  9SEP2017 23:34:49  44.4N  129.1W ML=3.3  EMSC   OFF COAST OF OREGON          

O: 10SEP2017 00:42:39  44.5N  129.1W ML=3.3  EMSC   OFF COAST OF OREGON          

P: 11SEP2017 110269    44.5N  129.8W 3.0-4.4 AAAAA  Off Coast of Oregon        

 

TOLL RISES IN GREAT MEXICAN EARTHQUAKE AFTERMATH

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 8, 2017

 

The strongest earthquake in eastern Mexico since 1902 was recalibrated to M 8.2 by NEIC today. This earthquake was probably triggered by a combination of plate motions induced from Hurricane Irma (horizontal) and Hurricane Katia (vertical); Solar Flare effects from the X9.3 solar flare of September 7 (the M 8.2 in Mexico occurred as the CME arrived at the earth and within minutes of the maximum geomagnetic storm, the strongest since March 2015) and effects of the full moon, the first since the solar eclipse of August 21 which maximized near the longitude of the earthquake in Mexico.

 

At least 58 are now confirmed dead and hundreds injured from the earthquake. The toll in the worst-hit areas of Chiapas and Oaxaca is expected to rise as rescue workers arrived in rural areas. Buildings were damaged as far as Mexico City during this midnight earthquake. Damage also occurred throughout Guatemala and some buildings were destroyed. The 58 deaths are more than the 26 reported from Hurricane Irma which was devastating the northern Carribean at the same time. Many (17) of the deaths occurred in Juchitan, Oaxaca. Many buildings including the town hall, a hotel and businesses were reduced to rubble in Juchitan. At least one person was also killed by the quake in Guatemala. Schools in 10 Mexican States were closed pending damage assessment. Millions of people were still without power. Tsunami waves also hit southern Mexico with heights of up to 3.3 meters (10 feet) were reported with this earthquake. The largest waves confirmed by PTWC however, were four feet in height near Salina Cruz but smaller waves were reported elsewhere in Chiapas and Oaxaca. As with many great earthquakes, earthquake lights were prominent with this event. Videos of these lights were made and published on the web as seen in Mexico City. As the quake occurred at the same time as the CME from the X9.3 solar flare of September 7, it is difficult to identify the source of these "earthquake lights" - whether from the largest geomagnetic storm in nearly 2.5 years or from changes in breaking rocks underground.  Hundreds of aftershocks, including dozens of M>=4 have been recorded. Most of these events are being felt in Oaxaca and Chiapas with light intensity.

 

A large foreshock hit the area on June 11 with M 6.9-7.0. The circumstances related to tidal stress (a full moon) and tropical cyclones (TD Calvin was in the area were remarkably similar to the current as noted in the summary from June 14, 2017:

 

"A major earthquake of M 6.9 (EMSC) to 7.0 (UNAM) occurred at an intermediate depth beneath Guatemala and Chiapas, Mexico near local solar midnight today. A foreshock of M 5.6 in Chiapas, Mexico preceded by about 50 minutes the earthquake in Guatemala. This is probably a tidal quake having occurred within about 15 minutes of local solar midnight. ....  When an area is near rupture this can be precipated by a large but non-major earthquake such as the event of M 6.3 in Turkey-Greece. Was the area of Chiapas-Guatemala ready for such a triggered event? This summary has been following an escalation of seismicity in Guatemala and Chiapas, Mexico over the past several days which began with the passage of Tropical Depression Calvin over these epicenters and was noted in the previous issue of this summary as: 

 

"Tropical depression Calvin (03E) continued in the area south of Oaxaca and Chiapas, Mexico with winds up to 40 kts. NHC This storm is located south of the Mexico-Guatemala border at this time and is expected to dissipate over land in the next two days. The area from Chiapas to Oaxaca could see a MODERATE TO LARGE EARTHQUAKE IN THE NEXT THREE DAYS. The area is under an earthquake watch." (June 12-13, 2017)

 

and

 

"The seismicity south of Chiapas, Mexico also appears to have promoted by a combination of stresses from the forming tropical depression over these epicenters and by strong tidal stresses associated with the full moon. The sequence began with an M 5.1-5.2 at 18:47 UT. Local solar noon is about 18:15 UT. Tidal stresses are high at this hour and, as in the case in Vancouver may have helped promote this earthquake at this time." (June 14, 2017)

 

Fifteen aftershocks of M>=5.0 were recorded today. The largest were M 5.3-5.4. Forecasts 110143 and 110144 had expected this activity was likely between September 6 and 9.

 

O: 09SEP2017 04:54:55  15.2N   93.8W Mw=5.4  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 08:34:36  15.3N   94.0W mb=5.3  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 22:28:44  15.4N   93.8W mb=5.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 16:19:19  15.4N   94.1W mb=5.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 18:00:30  15.5N   94.2W mb=5.0  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 16:08:09  15.5N   94.3W mb=5.1  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 12:06:19  15.5N   94.4W mb=5.2  EMSC   OFFSHORE OAXACA, MEXICO

O: 08SEP2017 14:45:00  15.6N   94.3W mb=5.4  EMSC   OFFSHORE OAXACA, MEXICO

O: 09SEP2017 02:43:44  15.6N   94.8W mb=5.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 08SEP2017 14:40:11  15.7N   94.3W mb=5.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 08SEP2017 17:02:54  15.7N   94.6W mb=5.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 08SEP2017 18:24:11  15.7N   95.0W mb=5.1  EMSC   OFFSHORE OAXACA, MEXICO

O: 08SEP2017 11:25:56  15.8N   94.8W mb=5.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 08SEP2017 14:24:56  16.0N   94.3W mb=5.1  EMSC   OFFSHORE OAXACA, MEXICO

O:  9SEP2017 00:01:24  16.9N   94.7W ML=4.9  EMSC   OAXACA, MEXICO               

P:  6SEP2017 110143    15.0N   94.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

P:  9SEP2017 110144    17.0N   94.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

 

An unusual M 3.2 earthquake today shook areas of Illinois, Indiana and Wisconsin. NEIC reported it was felt with intensity II-III in Illinois at Mount Carmel, Bone Gap, Browns, West Salem, Albion,  Owensville, Allendale, Ellery, Grayville, Saint Francisville, Lawrenceville, Greenup, Marion, Nokomis; in Lake Geneva, Wisconsin and in Indiana at Evansville, Vicennes, Princeton, Owensville.

This epicenter is within kms of the point of maximum solar eclipse of the

August 21, 2017. The last earthquake in Illinois within about 100 km of this epicenter was an M 3.4 on May 30, 2015 and prior to that similar quakes on November 20, 2012 and June 5, 2008. A moderate quake of M 5.4 hit today's epicenter on April 18, 2008 and today's event may be an aftershock of that. Forecast 110474 had expected this earthquake in mid-September. The M 8.2 in Mexico hours earlier may have helped promote this event in Illinois. 

 

O:  9SEP2017 04:15:29  38.4N   87.9W mb=3.2  EMSC   ILLINOIS                     

O: 09SEP2017 04:15:29  38.4N   87.9W md=2.9  ANSS   Mount Carmel Illinois

P: 16SEP2017 110474    38.0N   89.0W 2.0-4.3 CAAAA  New Madrid area             

 

The strongest earthquake of M 3.9 in southern Alaska today was the largest event in the U.S.  Forecast 110581 had expected this event within about 10 km of the epicenter was likely around September 12. NEIC reported this earthquake of M 3.9 in Alaska was felt with intensity II-III in the area(s) of Anchor Point, Homer and Soldotna, Alaska.

 

O:  8SEP2017 19:33:09  59.3N  152.6W ML=3.9  EMSC   SOUTHERN ALASKA              

O:  8SEP2017 17:37:28  60.0N  153.4W ML=3.3  EMSC   SOUTHERN ALASKA               

O:  8SEP2017 20:26:41  60.2N  153.2W Ml=3.0  EMSC   SOUTHERN ALASKA              

P: 12SEP2017 110581    60.0N  153.5W 3.2-4.9 AAAAA  Central Alaska             

 

GREAT EARTHQUAKE IN CHIAPAS, MEXICO FOLLOWS X9.3 SOLAR FLARE

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 7, 2017

 

A great earthquake of M 8.0 (EMSC) to 8.4 (UNAM) hit the area south of Oaxaca and Chiapas, Mexico today. It was felt widely from Guatemala City to Mexico City and as far north as Belize. This is the first earthquake in the world with M>=8.0 since an M 8.3 in Central Chile on September 16, 2015 and prior to that an M 8.2 on April 1, 2014 in the area of northern Chile. On average there is approximately two years between great earthquakes such as this. The last earthquake of M>=8.0 within about 300 km of today's epicenter occurred on August 6, 1942 and M 8.4 on September 23, 1902 and April 19, 1902. These were M 8.3-8.4 events. This earthquake had been anticipated in previous issues of this report because of several factors including the X9.3 solar flare yesterday, tidal stresses and the severe geomagnetic storms. It occurred within about an hour of local solar midnight, a time when these effects maximize. It is also directly west of  Hurricane Irma. Stresses on land associated with Irma probably were the major promotional effect triggering this earthquake but previous summaries had pinpointed it in some detail as follows:

 

GEOMAGNETIC PROMOTION:

 

The geomagnetic field was at severe storm conditions today.  The AP level was 38. High latitude geomagnetic field saw severe storm conditions with AP at 60.  Triggering of strong seismicity from the severe geomagnetic storms  today and tomorrow is likely and includes the M 8.0-8.4 quake in eastern Mexico today.  A flare of X1.3 occurred near UT noon today, This follows two similar quakes yesterday including an X9.3 the first X-class solar flare since an X2.1 on March 11, 2015 and the strongest flare in at least 11 year, the solar cycle period. Strong seismicity is likely to be promoted 10-15 degrees from the geomagnetic equator and at high auroral latitudes around September 10-13. This is most likely in areas near 90 East and West longitudes including Indonesia and Central America among others. This is a combined effect of weather, geomagnetic and tidal effects associated with the full moon. The earthquake today in eastern Mexico appears to confirm this analyses. The planetary K-index reached maximum of 8 today, around 0400 UT on September 8. This is the first time it has reach 8 since  March 17, 2015, two and a half years ago. The simultaneity of this geomagnetic storm and the M8+ at the same time in Chiapas, Mexico is powerful coincidental evidence for a triggering relation as previously noted in this summary on many occasions.

 

"Triggering of strong seismicity from the severe geomagnetic storms  today and tomorrow is likely to be delayed due in part to proton storms which along with the electron influx will disrupt ring currents and induced telluric currents. This in turn, will probably dial down seismicity until the ring currents can reform around September 9-12.  Strong seismicity is likely to be promoted 10-15 degrees from the geomagnetic equator and at high auroral latitudes around September 10-13. This is most likely in areas near 90 East and West longitudes including Indonesia and Central America among others. This is a combined effect of weather, geomagnetic and tidal effects associated with the full moon." (September 5-6, 2017)

 

"Hurricane Katia (Depression 13) continued today in the Gulf of Mexico with winds up to 80 kts. This storm is expected to circle clockwise making a second landfall around September 9-10 on the coast of eastern Mexico. The long period of atmospheric low pressure over the area north of Guerrero and Oaxaca, Mexico could promote a strong earthquake in this area in the next week. A seismic watch is being called for the area from Oaxaca west to Michoacan through September 11." (September 7, 2017)

 

"a moderate to strong earthquake around the Caribbean but this is not likely until mid-September after Irma passes into the Caribbean." (September 6-7, 2017)

 

SOLAR FLARE EFFECTS:

 

"A flare of X9.8 occurred near UT noon today, this is the first X-class solar flare since an X2.1 on March 11, 2015 and the strongest flare in at least 11 year, the solar cycle period. Strong seismicity is likely to be promoted 10-15 degrees from the geomagnetic equator and at high auroral latitudes around September 10-13. This is most likely in areas near 90 East and West longitudes including Indonesia and Central America among others. This is a combined effect of weather, geomagnetic and tidal effects associated with the full moon." (September 7, 2017)

 

NEIC reported maximum intensity IX in the region of Chiapas, Mexico. Intensity VII was reported from Tuxtla Gutierrez, Chiapas with V in La Tritaria, San Cristobal de las Casas, Mexico and VI in Solola, Guatemala. Lesser shaking was felt within about 700 km at intensity V-VI as far as Mexico City, Belize, Guatemala, Oaxaca, Chiapas, Puebla and other states of Mexico as far west of Jalisco. It was also reported felt with intensity II-III as far as 2000 km from the epicenter at San Antonio and Austin, Texas. Extreme damage probably occurred in the epicentral zone and internet pictures confirmed this. A tsunami warning with possible waves up to 3 meters was issued by PTWC. While a tsunami likely occurred, reports are unverified at this writing.

 

Internet photos showed extensive damage to buildings in eastern Mexico. At least two people were confirmed dead at this writing. Power was out as far as Mexico City and roofs were damaged throughout the area. In some areas roads were blocked with debris and hotel guests were trapped.

 

Forecast 110143 had expected this epicenter within about 25 km of today's event would be active around September 6. This epicenter is at 104 degrees from the Dodecanese quake of July 20 (M 6.7) and 106 degrees from the Auckland quake of July 11, 2017. These are distances at which strong seismic energy is  reflected to the surface after large earthquakes. It is likely that this weakened the region in preparation for today's great quake.

 

O: 07SEP2017 07:05:23  15.0N   93.9W mb=4.4  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 05:57:03  15.3N   94.2W mb=4.5  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 05:54:20  15.4N   93.8W mb=4.3  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 05:24:39  15.4N   94.4W mb=5.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 05:33:36  15.4N   94.4W mb=5.2  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 06:08:47  15.5N   94.8W ML=5.0  EMSC   OFFSHORE OAXACA, MEXICO

O: 08SEP2017 06:26:21  15.6N   94.3W mb=4.3  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 05:44:29  15.6N   94.6W mb=4.9  EMSC   OFFSHORE OAXACA, MEXICO

O: 08SEP2017 05:01:38  15.9N   94.1W mb=5.7  EMSC   OFFSHORE CHIAPAS, MEXICO

O: 08SEP2017 05:01:38  15.9N   94.1W mb=5.7  ANSS   SW of Paredon Mexico

O: 08SEP2017 04:49:21  15.1N   93.7W mw=8.1  ANSS   SW of Pijijiapan Mexico

O: 08SEP2017 05:44:28  15.5N   94.9W ML=5.6  UNAM  l SURESTE de SALINA CRUZ, OAX *: 1

O: 08SEP2017 05:33:38  15.2N   94.7W ML=5.7  UNAM  al SURESTE de SALINA CRUZ, OAX *:

O: 08SEP2017 05:24:35  15.2N   94.6W ML=5.8  UNAM  al SURESTE de SALINA CRUZ, OAX *:

O: 08SEP2017 05:17:42  15.6N   94.8W ML=6.1  UNAM  l SURESTE de SALINA CRUZ, OAX *: 1

O: 08SEP2017 04:49:20  14.9N   94.3W ML=8.4  UNAM  al SUROESTE de TONALA, CHIS *: 14.

O: 07SEP2017 07:05:26  14.8N   94.1W ML=4.7  UNAM  al SUROESTE de PIJIJIAPAN, CHIS *:

O:  8SEP2017 04:49:21  15.0N   93.8W Mw=8.1  EMSC   OFFSHORE CHIAPAS, MEXICO     

P:  6SEP2017 110143    15.0N   94.0W 3.5-5.5 AAAAA  Chiapas, Mexico            

 

A second epicenter in the Mexican Subduction Zone also saw a swarm of moderate events today. This area became active at local solar midnight and was probably activated by solar flares and tidal stresses which maximize their effects at this time. Forecast 110164 had expected this activity within about 100 km of this epicenter was also likely around September 6. This area may see a moderate to large event in the next several days as a regional aftershock of the M 8+ today to the east.

 

O: 07SEP2017 20:10:15  16.7N  100.1W ML=4.0  UNAM  l SUROESTE de ACAPULCO, GRO *: 16.

O: 07SEP2017 15:49:46  16.8N  100.1W ML=4.1  UNAM  l SUR de COYUCA DE BENITEZ, GRO *:

O: 07SEP2017 15:17:56  16.8N  100.1W ML=4.3  UNAM  l SUR de COYUCA DE BENITEZ, GRO *:

O: 07SEP2017 07:19:54  17.0N  100.1W ML=4.0  UNAM   NOROESTE de COYUCA DE BENITEZ, GR

O: 07SEP2017 07:17:45  17.0N  100.1W ML=4.2  UNAM   SUROESTE de COYUCA DE BENITEZ, GR

O: 07SEP2017 15:49:46  16.8N  100.1W ML=4.1  EMSC   OFFSHORE GUERRERO, MEXICO

O: 07SEP2017 15:17:56  16.8N  100.1W ML=4.3  EMSC   OFFSHORE GUERRERO, MEXICO

O: 07SEP2017 07:19:54  17.0N  100.1W ML=4.0  EMSC   GUERRERO, MEXICO

O: 07SEP2017 07:17:45  17.0N  100.1W ML=4.2  EMSC   GUERRERO, MEXICO

O:  7SEP2017 20:10:15  16.8N  100.1W ML=4.0  EMSC   OFFSHORE GUERRERO, MEXICO    

P:  6SEP2017 110164    18.0N  100.0W 3.5-5.2 ABAAA  Oaxaca, Mexico              

 

The second strongest earthquake in the world today was an M 6.1 in the Japanese Bonin Islands. As the focus of this event was at a deep hypocenter, the cone of felt activity was widespread on the surface. NEIC reported intensity II in Kanagawa, Japan at Yamoto and Sagamihara and in Tokyo, Japan. This may be a delayed reaction the passage of Typhoon Sanvu over this epicenter last week as noted in this summary:

 

"(Typhoon) Sanvu continued today over the Bonin Islands, Japan with winds up to 70 kts. It is expected to track to the north but not to reach Honshu. Areas if the Volcano Islands north to the Izu Islands may see typhoon force winds around September 1. No major earthquakes are expected with this storm but moderate increases in seismicity in southeastern Japan are likely in the next three days." (September 1-4, 2017)

 

Today's earthquake of M 6.1 is the largest in the Bonin Island within about 200 km of today's epicenter since an M 6.2 on August 4, 2016 and prior to that on June 23, 2015 with M 6.3, an aftershock of an M 7.5 on May 30, 2015.  Forecast 110170 had expected this event in the Bonin Islands was likely around September 11.

 

O:  7SEP2017 17:26:50  27.8N  139.8E Mw=6.1  EMSC   BONIN ISLANDS, JAPAN REGION  

P: 11SEP2017 110170    28.0N  142.0E 4.0-5.6 BABAA  Bonin Islands              

 

The strongest earthquake in the U.S. or Canada today was an M 4.7 in the Fox Islands, Aleutians, Alaska. It was not reported felt in this remote area.  This appears to be an aftershock of an M 5.5 on August 9, 2017, a month ago and also associated with the full moon. This epicenter was within minutes of local solar midnight when the X9.3 solar flare occurred on September 7. SFE from that flare likely promoted today's Fox Islands quake as suggested in the previous summary. Forecast 110563 had expected this event within about 25 km of the epicenter was likely in mid-September.

 

O:  8SEP2017 03:24:05  52.2N  169.2W mb=4.7  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

P: 14SEP2017 110563    52.4N  169.4W 3.5-4.9 CAAAA  Fox Islands, Aleutians     

 

The strongest earthquake in the U.S. or Canada today outside Alaska was an M 3.9 in Oklahoma. NEIC reported maximum intensity V in Oklahoma at Kremlin, and IV in Pond Creek, Lamont, Medford, Mardin, Enid, and within about 40 km of the epicenter. Intensity II-III was felt throughout Oklahoma within about 150 km of the epicenter. Lighter shaking of II-III intensity was felt locally in Tonkawa, Carrier, Blackwell, Braman and Ponca Cit among others. The quake was reported felt as far as Atchison, Kansas and Kansas City, Missouri. Stronger earthquakes in the area tend to fall near the times of full and new moons. This suggest a degree of upward promotion in the magnitudes of these events due to tidal stresses. The strongest earthquake in Oklahoma during 2007 has been an M 4.2 on August 3. Others of M>3.9 occurred on March 25, April 9, May 13, May 30, most of which were within a couple of days of full or new moon.

 

 

GIANT FLARE OF X9.3 SENDS CME TOWARDS EARTH

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 6, 2017

 

An X9.3 solar flare occurred today near UT noon. This is the largest flare in the current solar cycle - at least 11 years and the eighth largest in the past 25 years. The last solar flare of X9.0 or higher class occurred as an X9.0 flare on December 5, 2006. The last flare of higher class occurred as an X17.0 on October 28, 2003; an X10 on October 29, 2003 and an X28.0 on November 4, 2003. Solar flares of this class can have unexpected effects on global seismicity. A similar X-flare occurred  in conjunction with the Loma Prieta earthquake of October, 1989 in California. One of the strongest solar flares in recent years occurred on March 11, 1989 with X20. This summary described the flare in October, 2003 as follows:

 

 

"A strong X-class flare occurred around 11:00 UT on October 28. This X18 solar flare is the strongest observed during the current solar cycle. A seismic watch has been declared" (October 28, 2003)

 

and

 

"An extreme event in the geomagnetic field occurred today as the CME from

yesterday's X17-X18 solar flare hit at about 06-07UT on October 29. This summary expects this to have strong repercussions on the seismicity of central Asia and North and South America. Seismic watches currently in effect for these areas have been extended through early November, 2003. The impact of this CME caused the Kp value to raise from quiet to extreme storm within a few minutes. This can have effects from causing strong free earth oscillations to major effects on communications and power grids. The resulting electrical disruptions in the ionosphere and in the earth can lead to triggered seismic activity." (October 29, 2003)

 

The effects of this and the coming geomagnetic storm was published in this summary before the X-class flares occurred in yesterday's issue as"

 

"The geomagnetic field is expected to see severe storm conditions for the next two days. This is associated with particles from a series of M-class solar flares over the past two days. Seismicity, delayed by several days, will probably see several strong events associated with these geomagnetic storms. This is emphasized in the "GEOMAGNETIC" section of this summary as:

 

"Triggering of strong seismicity from the severe geomagnetic storms  today and tomorrow is likely to be delayed due in part to proton storms which along with the electron influx will disrupt ring currents and induced telluric currents. This in turn, will probably dial down seismicity until the ring currents can reform around September 9-12.  Strong seismicity is likely to be promoted 10-15 degrees from the geomagnetic equator and at high auroral latitudes around September 10-13. This is most likely in areas near 90 East and West longitudes including Indonesia and Central America among others. This is a combined effect of weather, geomagnetic and tidal effects associated with the full moon." (September 5-6, 2017) (September 6, 2017)

 

 

While the most likely promoted seismicity from the flare will occur around September 10-12, an unusual earthquake of M 3.8 in northern Italy accompanied the X9.3 flare. It was within minutes of local solar noon at the time of flare 7340 (X9.3) and SFE and/or tidal stresses were probably promotional factors to the timing of this event. The earthquake was felt with light to moderate intensity in Italy at Valcozzena an Pera according to EMSC. Several light aftershocks were also felt in the region. The last earthquake within about 100 km of this epicenter in northern Italy with M>=3.8 was an M 4.5 on June 9, 2012. The timing and rarity of this event suggest it was triggered by the X9.3 solar flare as the sun was directly overhead at the time. Forecast 110253 had expected an earthquake in this area of Italy around September 6.

 

O:  6SEP2017 12:30:32  46.3N   12.0E ML=3.3  EMSC   NORTHERN ITALY               

O:  6SEP2017 12:22:30  46.3N   12.0E ML=3.8  EMSC   NORTHERN ITALY               

P:  6SEP2017 110253    44.0N   11.0E 3.0-5.4 ACAAA  Italy                      

 

The strongest earthquake in an area near solar noon when the flare occurred however, occurred as an M 4.6 several hours later in Iceland. This earthquake occurred in a remote area of Iceland and was not felt. Iceland last saw an  earthquake of M>=4.5 within about 200 km of this epicenter on March 26, 2007 when a series of events of M 5.0 and 4.6 occurred. Today's epicenter, however has not seen an M 4.5 or greater during 2017. The last such event within about 100 km of this epicenter was an M 4.5 on April 8, 2016 and prior to that part of a series in 2014 and 2015 on February 13. 2015. The solar flare appears to be a prime promoter of today's event.  Forecast 110313 had expected today's event within about 25 km of the epicenter was likely around September 8. 

 

O:  7SEP2017 03:08:17  64.7N   17.2W mb=4.5  EMSC   ICELAND                      

O:  7SEP2017 02:15:37  64.7N   17.5W ML=3.2  EMSC   ICELAND                      

P:  8SEP2017 110313    65.0N   17.0W 3.0-4.6 AAAAA  Iceland area               

 

On the other end of the Atlantic, the second strongest earthquake of the day occurred in the South Atlantic in the South Sandwich Islands about an hour after the X9.3 flare. This was also probably triggered by SFE. Forecast 110371 had expected this event in the South Sandwich Islands around September 5.

 

O:  6SEP2017 13:45:08  57.7S   25.3W mb=5.0  EMSC   SOUTH SANDWICH ISLANDS REGION

P:  5SEP2017 110371    56.0S   27.0W 4.0-5.8 ABAAA  So. Sandwich Islands       

 

An earthquake of M 4.8 also occurred south of Australia in the Western Indian-Antarctic Ridge. This was not felt in this remote area. The last earthquake of M>4.8 within about 200 km of this epicenter was an M 5.1 on August 1, 2017 and prior to that as an M 5.0 on November 3, 2013. Forecast 110368 had expected a moderate regional event in this area was likely around September 2. The earthquake was simultaneous with flare #7250 which ended at 0917 UT, the first X-class flare of this size in more than a year and was probably promoted by SFE.

 

O:  6SEP2017 09:16:17  49.3S  116.7E mb=4.8  EMSC   WESTERN INDIAN-ANTARCTIC RIDGE

P:  2SEP2017 110368    49.0S  122.0E 4.0-5.4 BACAA  So. of Australia           

 

On the other side of the world, the two largest earthquakes of the day occurred in the Tonga with M 5.1 and Fiji Islands with M 4.9. These two events were within minutes of local solar midnight when the X9.3 flare occurred, a prime time for triggering by Solar Flare Effects (SFE). The M 4.9 south of Fiji was a local solar noon event and was probably promoted by flares and tidal stresses. It had been  expected within about 100 km of this epicenter in early September in forecast 110354.

 

O:  6SEP2017 19:05:52  15.5S  173.6W mb=5.1  EMSC   TONGA                        

P:  3SEP2017 110339    17.0S  173.0W 4.0-5.4 BBAAA  Tonga Islands              

 

O:  7SEP2017 00:24:32  24.8S  179.8E mb=4.9  EMSC   SOUTH OF FIJI ISLANDS        

P:  3SEP2017 110354    25.0S  179.0E 4.0-5.8 BAAAA  Tonga/Fiji                 

 

The X9.3 was preceded at 0917 UT by an X2.2 solar flare, the strongest in  more than a year. An earthquake of M 4.8 on the western Indian/Antarctic Ridge occurred at the same time and may have been promoted by the flare. Earthquakes in the Montana and Idaho aftershock zones proliferated following this flare and may have also been promoted. It was near local solar noon in the northwest U.S. when this flare occurred.

 

NEIC reported the earthquake of M 4.1 in Southern Idaho was felt with intensity II-III in the area(s) of Soda Springs, Idaho.

 

O: 06SEP2017 16:49:53  42.5N  111.4W ML=2.7  EMSC   SOUTHERN IDAHO

O: 06SEP2017 12:42:21  42.5N  111.4W ML=2.9  EMSC   SOUTHERN IDAHO

O: 06SEP2017 16:35:13  42.5N  111.4W ML=3.2  EMSC   SOUTHERN IDAHO

O: 06SEP2017 08:26:30  42.6N  111.3W Mw=4.1  EMSC   SOUTHERN IDAHO

O: 06SEP2017 13:59:48  42.6N  111.4W ML=2.2  EMSC   SOUTHERN IDAHO

O: 06SEP2017 09:36:02  42.6N  111.4W ML=2.3  EMSC   SOUTHERN IDAHO

O: 06SEP2017 17:54:45  42.6N  111.4W ML=2.6  EMSC   SOUTHERN IDAHO

O: 06SEP2017 22:49:32  42.6N  111.4W ML=2.6  EMSC   SOUTHERN IDAHO

O: 06SEP2017 16:26:54  42.6N  111.4W ML=3.1  EMSC   SOUTHERN IDAHO

O: 06SEP2017 11:41:47  42.6N  111.4W ML=3.2  EMSC   SOUTHERN IDAHO

O: 06SEP2017 15:04:47  42.6N  111.4W ML=3.2  EMSC   SOUTHERN IDAHO

O: 06SEP2017 07:32:22  42.6N  111.4W ML=3.5  EMSC   SOUTHERN IDAHO

O: 06SEP2017 07:55:10  42.6N  111.4W ML=4.1  EMSC   SOUTHERN IDAHO

O: 06SEP2017 15:37:21  42.6N  111.5W ML=2.5  EMSC   SOUTHERN IDAHO

O: 06SEP2017 16:55:44  42.6N  111.5W ML=2.5  EMSC   SOUTHERN IDAHO

O: 06SEP2017 10:50:58  42.6N  111.5W ML=2.6  EMSC   SOUTHERN IDAHO

O: 06SEP2017 11:45:49  42.6N  111.5W ML=2.6  EMSC   SOUTHERN IDAHO

O: 06SEP2017 18:29:30  42.6N  111.5W ML=2.6  EMSC   SOUTHERN IDAHO

O: 06SEP2017 10:14:45  42.6N  111.5W ML=2.8  EMSC   SOUTHERN IDAHO

O: 06SEP2017 12:09:17  42.6N  111.5W ML=2.8  EMSC   SOUTHERN IDAHO

O: 06SEP2017 13:29:19  42.6N  111.5W ML=2.8  EMSC   SOUTHERN IDAHO

O: 06SEP2017 20:23:57  42.6N  111.5W ML=2.8  EMSC   SOUTHERN IDAHO

O: 06SEP2017 11:18:47  42.6N  111.5W ML=3.0  EMSC   SOUTHERN IDAHO

O: 06SEP2017 09:52:54  42.6N  111.5W ML=3.1  EMSC   SOUTHERN IDAHO

O: 06SEP2017 07:51:08  42.6N  111.5W ML=3.5  EMSC   SOUTHERN IDAHO

O: 06SEP2017 09:10:54  42.6N  111.5W ML=3.5  EMSC   SOUTHERN IDAHO

O:  6SEP2017 22:58:24  42.7N  111.5W ML=2.6  EMSC   SOUTHERN IDAHO                

P:  8SEP2017 110283    43.0N  111.5W 2.0-4.1 AAAAA  Yellowstone/Wyoming        

 

COMING SEVERE GEOMAGNETIC STORMS LIKELY TO AFFECT GLOBAL SEISMICITY

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 5, 2017

 

The geomagnetic field is expected to see severe storm conditions for the next two days. This is associated with particles from a series of M-class solar flares over the past two days. Seismicity, delayed by several days, will probably see several strong events associated with these geomagnetic storms. This is emphasized in the "GEOMAGNETIC" section of this summary as:

 

"Triggering of strong seismicity from the severe geomagnetic storms  today and tomorrow is likely to be delayed due in part to proton storms which along with the electron influx will disrupt ring currents and induced telluric currents. This in turn, will probably dial down seismicity until the ring currents can reform around September 9-12.  Strong seismicity is likely to be promoted 10-15 degrees from the geomagnetic equator and at high auroral latitudes around September 10-13. This is most likely in areas near 90 East and West longitudes including Indonesia and Central America among others. This is a combined effect of weather, geomagnetic and tidal effects associated with the full moon." (September 5-6, 2017)

 

The strongest earthquake in the world today was an M 5.4 in the Andaman Islands of India. This is the strongest earthquake in the Andaman Islands since a similar M 5.4 on April 5, 2017. It was not reported felt in this area. Forecast 110139 had expected this event within about 25 km of this epicenter was likely around September 7. 

 

O:  6SEP2017 00:10:56  10.2N   93.1E Mw=5.4  EMSC   ANDAMAN ISLANDS, INDIA REGION

P:  7SEP2017 110139    10.0N   93.0E 4.0-5.6 AAAAA  Andaman Islands            

 

Aftershocks continued in the Southern Idaho sequence today. The strongest was an M 4.5. This is a very active and slowly declining sequence but in many ways resembles other aftershock sequence following strong events in the area including the Hebgen Lake quake of 1959 and the Western Montana quake of July 6. The M 4.5 today was reported by NEIC to have been felt with maximum intensity IV in Soda Springs, Idaho and II-III in Idaho at Grace, Montpelier, Lava Hot Springs, Paris, Downey, Inkom, Pocatella, Shelley, Rexburg; in Utah at Salt Lake City, and in Wyoming at Auburn, Afton, Thayne, Bedford, Freedom, Grover, Etna, and Jackson.

 

O: 05SEP2017 23:00:17  42.5N  111.4W ML=3.6  EMSC   SOUTHERN IDAHO

O: 06SEP2017 08:26:31  42.6N  111.3W ML=3.8  EMSC   SOUTHERN IDAHO

O: 06SEP2017 02:36:17  42.6N  111.4W ML=2.6  EMSC   SOUTHERN IDAHO

O: 06SEP2017 00:37:10  42.6N  111.4W ML=2.7  EMSC   SOUTHERN IDAHO

O: 06SEP2017 01:00:16  42.6N  111.4W ML=2.8  EMSC   SOUTHERN IDAHO

O: 06SEP2017 02:26:41  42.6N  111.4W ML=3.0  EMSC   SOUTHERN IDAHO

O: 05SEP2017 22:32:47  42.6N  111.4W ML=3.4  EMSC   SOUTHERN IDAHO

O: 06SEP2017 07:32:22  42.6N  111.4W ML=3.5  EMSC   SOUTHERN IDAHO

O: 06SEP2017 04:36:29  42.6N  111.4W ML=3.8  EMSC   SOUTHERN IDAHO

O: 06SEP2017 07:55:10  42.6N  111.4W ML=4.1  EMSC   SOUTHERN IDAHO

O: 05SEP2017 14:46:42  42.6N  111.5W ML=2.7  EMSC   SOUTHERN IDAHO

O: 05SEP2017 22:46:58  42.6N  111.5W ML=2.9  EMSC   SOUTHERN IDAHO

O: 06SEP2017 01:08:42  42.6N  111.5W ML=2.9  EMSC   SOUTHERN IDAHO

O: 06SEP2017 02:38:44  42.6N  111.5W ML=2.9  EMSC   SOUTHERN IDAHO

O: 06SEP2017 04:27:42  42.6N  111.5W ML=3.0  EMSC   SOUTHERN IDAHO

O: 06SEP2017 02:22:11  42.6N  111.5W ML=3.2  EMSC   SOUTHERN IDAHO

O: 06SEP2017 07:51:08  42.6N  111.5W ML=3.5  EMSC   SOUTHERN IDAHO

O:  6SEP2017 04:37:45  42.6N  111.5W Mw=4.5  EMSC   SOUTHERN IDAHO               

P:  8SEP2017 110283    43.0N  111.5W 2.0-4.1 AAAAA  Yellowstone/Wyoming        

 

Light earthquakes continued in the San Francisco Bay area today with an M 2.5. NEIC reported this event was felt with intensity II-III in Milpitas, San Jose, Soquel and San Rafael, California. Forecast 110192 had expected this activity was likely around September 5.

 

O:  5SEP2017 20:02:09  37.4N  121.8W MD=2.5  EMSC   SAN FRANCISCO BAY AREA, CALIF.

O:  6SEP2017 01:24:38  37.6N  122.0W Md=2.1  EMSC   SAN FRANCISCO BAY AREA, CALIF.

P:  5SEP2017 110192    37.9N  122.0W 2.5-4.5 AAAAA  Central California         

 

A light earthquake of M 3.8 occurred near Vancouver, British Columbia today. NEIC reported it was felt with intensity II-III in British Columbia at Ucluelet, Port Alberni, Parksville, Nanaimo, Walnut Grove and Port Hardy. Earthquakes Canada reported it was felt in Ucluelet, Tofino, Port Alberni, Errington and Nanaimo with no reports of damage. It followed about fifteen minutes after an M 2.8 off the coast of central Oregon, an event which was reported felt with intensity II in Terrebonne, Oregon. An earthquake of M 4.3 off the coast of Oregon was reported felt with intensity II in Coos Bay, Oregon. These last two events fall on the path of totality of the solar eclipse of August 21 and were probably promoted by tidal stresses associated with the full moon which arrives today as previously noted in this summary:

 

"The full moon will arrive on September 6 at 07:03 UT. Longitudes which are antisolar at this time (local solar midnight) are near 110 West while those which are subsolar (local solar noon) are near 70 East longitude. These include areas of the Rocky Mountains and western Mexico in the west and central Asia in the east. It is in these regions where the highest probability of tidal triggering exists for the next week. Many areas can, however, see enhanced seismicity due to earth tides associated with the full moon and are not exclusive to these longitudes." (September 3-6, 2017)

 

The last earthquake in British Columbia with M>=3.8 within about 100 km of

the Vancouver Island event was an M 3.9 on June 19, 2017 and prior to that an M 4.8 on January 8, 2015.  Forecast 110282 had expected this event was likely in early September to the east of today's epicenter.

 

O:  5SEP2017 09:52:00  43.6N  127.4W mb=4.3  EMSC   OFF COAST OF OREGON          

P:  4SEP2017 110269    43.9N  128.4W 3.0-4.7 AAAAA  Off Coast of Oregon        

 

O:  5SEP2017 15:48:10  44.3N  124.3W ML=2.8  EMSC   OFFSHORE OREGON              

O:  6SEP2017 05:09:02  46.4N  122.3W MD=2.1  EMSC   WASHINGTON                   

P:  3SEP2017 110282    46.9N  122.0W 2.0-4.3 AAAAA  Washington state, U.S.     

 

O:  5SEP2017 16:08:37  49.1N  125.5W ML=3.8  EMSC   VANCOUVER ISLAND, CANADA REGIO

O: 05SEP2017 16:08:34  49.0N  125.5W ML=3.6  NRCA  6 km NE  of Ucluelet

P:  2SEP2017 110282    48.9N  123.1W 2.0-4.3 BABAA  Washington state, U.S.     

 

A second active site also saw two light earthquakes in Western Texas today. These events were not reported felt in this epicentral area but may be related to stresses from Hurricane Harvey. This is not the area of Pecos, Texas but another site near Snyder, Texas which has occasionally experienced minor earthquakes. Two earthquakes of M 2.6-2.7 on August 13 and May 6, the only such during 2017. Forecast 110216 had expected regional activity in this area in early September.

 

O:  6SEP2017 08:02:48  32.9N  100.9W mb=2.7  EMSC   WESTERN TEXAS                

O: 05SEP2017 21:37:41  32.8N  100.9W mb=2.5  ANSS   N of Snyder Texas

O: 06SEP2017 08:02:48  32.9N  100.9W mb=2.7  ANSS   N of Snyder Texas

P: 10SEP2017 110216    35.4N  101.8W 2.0-4.1 BCAAA  SW U.S.A                   

 

STRONG SWARM IN NORTHERN VIRGIN ISLANDS; ECLIPSE QUAKES CONTINUE

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 4, 2017

 

Two moderate earthquakes of M 4.3 and M 4.4 occurred today along the path of total eclipse during the event of August 21. The stronger of these was an M 4.4 aftershock in southern Idaho, but an M 4.3 also occurred off the coast of Oregon directly in the total eclipse path. The eclipse, however, was not the only contributor to promoting seismicity today. Hurricane Irma reached the northern Virgin Islands today and was accompanied by an unusually strong series of earthquakes in the area of landfall. A tropical Depression off eastern Mexico also appeared ready to promote larger seismic events in the Mexican subduction zone.

 

The earthquake of M 4.3 off the coast of Oregon occurred near local solar midnight in an area which had been expected to see a moderate eclipse-related event at  this time as noted in previous summaries including that of August 28 when a similar M 4.3 occurred as a foreshock to today's event:

 

"The most unusual earthquake in the U.S., Canada or environs today was an M 4.3 off the coast of Oregon. It was reported by NEIC to have been felt at Coos Bay, Oregon with light intensity. This appears to be a delayed eclipse-related event, the strongest to day on the path of totality of the eclipse of August 21. It had been expected in this summary as:

 

"The strongest seismicity along the eclipse path in the U.S. occurs off the west coast of Oregon and this area of converging plates may see a moderate earthquake in the next several days." (August 21, 2017)

 

The last earthquake of M>=4.3, and only such event during 2017 within about 150 km of this epicenter off the coast of Oregon was an M 4.4 on May 13. Forecast 110025 had expected this earthquake was likely around August 28." (August 28, 2017)

 

 

O:  5SEP2017 09:52:00  43.6N  127.4W mb=4.3  EMSC   OFF COAST OF OREGON          

O: 05SEP2017 09:52:00  43.6N  127.4W mb=4.3  ANSS   WNW of Bandon Oregon

P:  4SEP2017 110269    43.9N  128.4W 3.0-4.7 AAAAA  Off Coast of Oregon        

 

Moderate aftershocks in Idaho continued today with a maximum of M 4.4. These were reported by NEIC to have been felt with intensity II-III in Idaho at Soda Springs, Grace, Montpelier, Malad City, Pocatello, Firth, Franklin, Downey, Preston, Lava Hot Springs, Paris,  and in Wyoming at Auburn, Smoot, Afton, Thayne, and Rock Springs and in Lewiston, Utah. Forecast 110283 (published before the mainshock) had expected this activity at this time.

 

O: 05SEP2017 02:05:38  42.6N  111.4W ML=3.1  EMSC   SOUTHERN IDAHO

O: 05SEP2017 10:02:02  42.6N  111.4W ML=3.1  EMSC   SOUTHERN IDAHO

O: 05SEP2017 09:47:11  42.6N  111.4W ML=3.2  EMSC   SOUTHERN IDAHO

O: 04SEP2017 22:15:47  42.6N  111.4W ML=3.5  EMSC   SOUTHERN IDAHO

O: 04SEP2017 19:04:58  42.6N  111.4W ML=3.6  EMSC   SOUTHERN IDAHO

O: 04SEP2017 19:04:58  42.6N  111.4W ML=3.6  EMSC   SOUTHERN IDAHO

O: 04SEP2017 20:46:55  42.6N  111.5W ML=2.6  EMSC   SOUTHERN IDAHO

O: 04SEP2017 22:10:31  42.6N  111.5W ML=2.8  EMSC   SOUTHERN IDAHO

O: 04SEP2017 20:17:28  42.6N  111.5W ML=3.0  EMSC   SOUTHERN IDAHO

O: 05SEP2017 03:38:51  42.6N  111.5W ML=3.0  EMSC   SOUTHERN IDAHO

O: 05SEP2017 04:34:33  42.6N  111.5W ML=3.1  EMSC   SOUTHERN IDAHO

O: 04SEP2017 22:47:42  42.6N  111.5W ML=3.2  EMSC   SOUTHERN IDAHO

O: 05SEP2017 02:28:31  42.6N  111.5W ML=3.4  EMSC   SOUTHERN IDAHO

O: 05SEP2017 02:28:31  42.6N  111.5W ML=3.4  EMSC   SOUTHERN IDAHO

O: 04SEP2017 20:51:38  42.6N  111.5W ML=3.5  EMSC   SOUTHERN IDAHO

O: 05SEP2017 03:21:10  42.6N  111.5W ML=3.5  EMSC   SOUTHERN IDAHO

O: 04SEP2017 20:12:23  42.6N  111.5W ML=3.7  EMSC   SOUTHERN IDAHO

O: 04SEP2017 23:14:45  42.6N  111.5W ML=3.7  EMSC   SOUTHERN IDAHO

O: 05SEP2017 00:34:41  42.6N  111.5W ML=3.8  EMSC   SOUTHERN IDAHO

O: 05SEP2017 01:32:39  42.6N  111.5W ML=4.0  EMSC   SOUTHERN IDAHO

O: 05SEP2017 03:12:37  42.6N  111.5W Mw=3.9  EMSC   SOUTHERN IDAHO

O: 04SEP2017 18:49:19  42.7N  111.5W ML=2.6  EMSC   SOUTHERN IDAHO

O: 04SEP2017 12:21:20  42.7N  111.5W ML=2.7  EMSC   SOUTHERN IDAHO

O: 04SEP2017 12:29:25  42.7N  111.5W ML=2.8  EMSC   SOUTHERN IDAHO

O: 04SEP2017 12:26:34  42.7N  111.6W ML=2.7  EMSC   SOUTHERN IDAHO

O:  5SEP2017 08:13:15  42.6N  111.4W mb=4.4  EMSC   SOUTHERN IDAHO               

P:  8SEP2017 110283    43.0N  111.5W 2.0-4.1 BAAAA  Yellowstone/Wyoming        

 

A small M 2.0 in Arkansas also occurred today in the path of total eclipse of August 21. This may be an aftershock of an M 3.6 about 25 km southwest of this epicenter on June 11. Forecast 110204 expected regional activity in early September.

 

O:  5SEP2017 12:38:43  36.5N   92.8W Md=2.0  EMSC   ARKANSAS                     

P:  2SEP2017 110204    38.0N   91.0W 2.0-4.3 BBBAA  New Madrid area            

 

The strongest earthquake in the U.S. or Canada today was an M 4.6 south of Alaska. It was not reported felt in this remote area. The only event of similar or larger size south of Alaska within about 200 km of this epicenter during 2007 was an M 4.7 on August 12. An M 4.5 also hit in the region August 19. These are the largest events in the area to date during 2007. Forecast 110286 had expected this event within about 200 km of the epicenter around September 6.

 

O:  5SEP2017 08:23:56  55.8N  153.0W mb=4.6  EMSC   SOUTH OF ALASKA              

P:  6SEP2017 110286    54.7N  156.9W 3.5-4.9 ABCAA  Alaska Peninsula           

 

Three light earthquakes of M 3.6, 3.7 and 3.8 in the region north of the Virgin Islands announced the arrival of Hurricane Irma today. Only one earthquake of  larger magnitude has hit in this region during 2017 - an M 4.7 on July 22, 2017. At the time this summary noted:

 

"An unusual earthquake also occurred north of the Virgin Islands today with M 4.7. From its position it appears to be an outer rise event. Such events often precede strong suduction zone earthquakes and in some cases can be precursory. This is by far the strongest earthquake in this region during 2017. Two previous events on July 9 (M 3.6) and on January 27 (M 3.7) had occurred. The last event of M>=4.7 in the area occurred on July 16, 2015 (M 4.8) and January 10, 2013 (M 5.0). The strongest event in the past 25 years in this area was an M 5.4 on December 28, 1992." (July 22, 2017) 

 

Forecasts 110169 and 110152 had expected this activity between September 4 and September 7. It had been expected as triggered activity associated with Hurrican Irma in the previous summary:

 

"Current track forecasts suggest landfall near the Virgin Islands which are likely to see an earthquake swarm with this storm." (September 4, 2017)

 

O:  4SEP2017 16:36:54  19.8N   64.1W MD=3.8  EMSC   NORTH OF THE VIRGIN ISLANDS  

O:  5SEP2017 07:40:34  19.9N   64.1W MD=3.7  EMSC   NORTH OF THE VIRGIN ISLANDS  

P:  7SEP2017 110169    20.0N   63.0W 3.0-4.5 AAAAA  Bahamas/No. Caribbean      

 

O:  4SEP2017 16:11:56  19.9N   64.3W MD=3.6  EMSC   NORTH OF THE VIRGIN ISLANDS  

P:  4SEP2017 110152    19.0N   64.0W 3.0-5.1 AAAAA  Leeward Islands            

 

Global seismicity may be set to ramp up to a higher level in the next several days. While the largest earthquake in the world today was an M 5.5 in the Vanuatu Islands which was unfelt, flares on the sun were increasing in size. The largest was an M5.8, the first of that size since April, 2017. This was accompanied by several other flares of M-class (see GEOMAGNETIC section below for complete listing). Strong flares can have an immediate Solar Flare Effect (SFE) on seismicity and often increase the size of subsequent earthquakes into the strong to major  categories near the geomagnetic equator or at high latitudes. A global seismic watch is therefore in effect through September 13. During this time a strong to major earthquake is likely near the geomagnetic equator or in combination with the full moon or a hurricane of typhoon.

 

O:  5SEP2017 02:50:02  16.2S  168.0E Mw=5.5  EMSC   VANUATU                       

P:  5SEP2017 110342    18.0S  168.0E 4.0-5.4 AAAAA  Vanuatu Islands            

 

EXPLOSION IN NORTH KOREA HAS LITTLE EFFECT ON GLOBAL SEISMICITY - OR NOT?

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 3, 2017

 

The big news from seismology today was the detection of a M 6.3 explosion in North Korea. This may have been a thermonuclear device or hydrogen bomb as claimed by North Korean sources. Shaking was felt widely within at least 250 km of the blast. Intensity V was felt in North Korea in the Yanggang region at Sungjibaegam, Kapsan, and Hyesan and in China in the Jilin area at Songjianghe, Yanji, and Badaojiang, China. Lesser tremor was felt in Hamhung, North Korea, in South Korea at Seoul, Shiheung, Chemulpo, Ch'onan, and in Jilin, China at Linjiang, Tumen, Hunchun, Dunhua, Dongchang, Huadian, Huinan, Jilan, It was  also reported felt at Vladivostok, Russia and as far as Tokyo, Japan with light intensity more than 1000 km from the blast site. Explosions such as this are easily determined by first arrivals, all of which are compressive. No stress is released as would happen in an earthquake. The daily earthquake map included in this summary shows nodal distances from North Korea today. No seismic increases at nodal distances from the explosion have been in detected at this time, and they are not expected since no stress was released. At M 6.3 this event is on the low side of earth disturbances expected to trigger far-field activity. A good sized hurricane is far more powerful and likely to trigger seismicity at a distance. Some news agencies reported the blast triggered a M 6.3 earthquake and aftershock of M 4.7. This is not true, the M 6.3 was the blast itself and the "aftershock" was a collapse of the hole created by the explosion. This is typical of underground explosions and has been seen many times in the Nuclear Test Site in Nevada. While most testing outside North Korea is now done on computers tests in the U.S. were generally smaller than today's. Some tests in Russia far exceeded  it, however. These were generally conducted in the Severnaya Zemlya area of the Arctic Ocean and included several equivalent to M>7. The largest of these was conducted on October 27, 1973 and was an M 7.6 event north of Siberia. Light from the explosion was seen as far as Canada. Oddly, the only earthquake on record of M>=4 in the State of Florida also occurred on October 27, 1973 in close association with this test. This is particular odd because the Florida event occurred 48 minutes before the explosion. This could be a coincidence of monumental proportion or there could be some unknown physics to be discovered here. Similar distant "foreshocks" have been observed prior to the largest earthquakes in the U.S. For example, the strongest earthquake in South Dakota occurred just prior to the largest earthquake in the U.S. in recorded history - the M 9+ earthquake on Good Friday, March 28, 1964 near Anchorage, Alaska. In this case one can make up stories about interactions because both are tectonic events, but such stories are far more difficult to make convincing in the October 27, 1973 earthquake/blast. The  blast in North Korea was preceded by several hours by one of the largest earthquakes in southern Idaho in recent history - is this another case of "distant foreshock" or another "coincidence". This summary does not trust "coincidence" as an explanation for much, considering it just a lazy way to dismiss near simultaneous phenomena which may or may not be related to each other or to another unexplored phenomenon.

 

O:  3SEP2017 03:30:01  41.3N  129.0E mb=6.3  EMSC   NORTH KOREA                  

O:  3SEP2017 03:38:31  41.4N  129.0E ML=4.1  EMSC   NORTH KOREA                  

 

 

The strongest activity in the U.S. or Canada continued today as aftershocks of the M 5.3 in Southern Idaho that occurred yesterday. The strongest of these was an M 4.8 but many aftershock of M>=3 were also recorded. These were generally felt with intensity II-III in Southern Idaho at Malad City and Lava Hot Springs and in Jackson, Wyoming. Events of M 4.5 and M 4.3 were reported with intensity IV in Lava Hot Springs, Soda Springs and Bancroft, Idaho and lesser intensity at Inkom, Arimo, Swan Valley, Idaho Falls, Pingree, Aberdeen, Rexburg, Grace,

Montpelier, Paris, Pocotello, Malad City, Idaho Falls, Blackfoot, Preston, Idaho and in Wyoming at Green River, Rock Springs, Smoot, Afton, Thayne, Grover, Etna, and as far as northern Utah at Mendon, Portage, Tremonton, Salt Lake City, Alpine, Ogden, Midway, Lindon, Orem, and Clearfield.  Forecast 110283 had expected this activity within about 50 km of this epicenter was likely in early September. Listed here are only the aftershocks of M>=4, a complete listing can be found of M>=3 in the "ROCKY MOUNTAIN" regional earthquake listings below.

 

O: 04SEP2017 06:17:09  42.6N  111.4W mb=4.3  EMSC   SOUTHERN IDAHO

O: 03SEP2017 17:41:42  42.6N  111.4W mb=4.8  EMSC   SOUTHERN IDAHO

O: 03SEP2017 02:29:23  42.6N  111.5W mb=4.2  EMSC   SOUTHERN IDAHO

O:  3SEP2017 16:49:17  42.6N  111.3W mb=4.7  EMSC   SOUTHERN IDAHO               

P:  8SEP2017 110283    43.0N  111.5W 2.0-4.1 BAAAA  Yellowstone/Wyoming        

 

In San Francisco, California an earthquake of M 2.6 was widely felt today. This follows record-breaking heat including a day of 107 F degrees over the past  several days. The heat spell in California has helped ignite the largest blaze ever in the Los Angeles area where fires have burned an area the size of Rhode Island. The earthquake in San Francisco today was reported by NEIC to have been felt with intensity II-III in Concord, Pleasant Hill, Walnut Creek, Lafayette, Martinez, Alamo, Benicia, Orinda, Clayton, Berkeley, Castro Valley, San Francisco, South San Francisco, Santa Clara, Petaluma, San Jose, Willits and possibly Redding, California. This is the strongest earthquake in the San Francisco Bay area since a similar M 2.6 on August 30 and prior to that on June 21, 2017 with M 3.0. Forecast 110192 had expected this earthquake was likely within about 10 km of the epicenter around September 5.

 

O:  4SEP2017 06:49:01  38.0N  122.1W MD=2.6  EMSC   SAN FRANCISCO BAY AREA, CALIF.

O: 04SEP2017 06:49:01  38.0N  122.1W md=2.6  ANSS   Pleasant Hill California

P:  5SEP2017 110192    37.9N  122.0W 2.5-4.5 AAAAA  Central California         

 

Seismicity in the Pecos area of Western Texas continued today with events of M 3.4 and 3.1. The M 3.4 is the strongest in the current series which reinvigorated with the passage of Hurricane Harvey near the area in late August, 2017. The last earthquake of M>=3.4 in the area occurred on September 6, 2016 with M 3.5-3.6, the only other such earthquake in the area in the past 25 years. The summary for September 6, 2016 emphasized tropical storm related seismicity.  Forecast 110216 had expected today's activity within about 30 km of these epicenters was likely around September 2. Today's earthquakes occurred within 30 minutes of local solar midnight and may have been promoted by tidal stresses.

 

O:  3SEP2017 06:27:39  31.2N  103.3W ML=3.4  EMSC   WESTERN TEXAS                

O:  3SEP2017 06:24:37  31.2N  103.4W ML=3.1  EMSC   WESTERN TEXAS                

P:  2SEP2017 110216    31.5N  103.6W 2.0-4.1 AAAAA  SW U.S.A                   

 

The strongest earthquake in the world today was an M 6.0 in the South Sandwich Islands region. It was preceded by an M 5.0 about 200 km to the south two hours earlier. Neither of these events were reported felt in this remote area.

The M 6.0 was the second of M>=6 during 2017. The other was an M 6.4 about 100 km south of this on May 10. Forecast 110371 had expected a moderately large earthquake was likely in this region around September 5.

 

O:  4SEP2017 08:07:36  57.8S   25.7W Mw=6.0  EMSC   SOUTH SANDWICH ISLANDS REGION

P:  5SEP2017 110371    56.0S   27.0W 4.0-5.8 ABAAA  So. Sandwich Islands       

 

O:  4SEP2017 06:18:14  59.5S   25.6W mb=5.0  EMSC   SOUTH SANDWICH ISLANDS REGION

P:  9SEP2017 110372    61.0S   26.0W 4.0-5.4 BBAAA  Southern  Ocean            

 

The earthquake in the South Sandwich Islands of M 6.0 followed an M 5.6 in the Volcano Islands/northern Mariana Islands area at 144 degrees distance. Earthquake energy is reflected and refracted off core boundaries and returns to the surface at this distance, possibly triggering additional seismicity such as the  South Sandwich Islands earthquakes. The earthquake in the Volcano Islands was probably promoted by Typhoon Sanvu which passed over this epicenter several days ago as reported in this summary:

 

"A moderate earthquake of M 4.5 in the Volcano Islands today may have been  triggered by passage of Tropical Storm Sanvu over the epicenter today. This had been expected, along with some additional activity to the north in this summary as:

 

"TS    SANVU    2017-08-29  00:00 UT  21.6N  147.7E  050 kts  Volcano Islands, Japan

 

TS formed today over the Volcano Islands, Japan with winds up to 50 kts. It is expected to track to the north but not to reach Honshu. Areas if the Volcano Islands north to the Izu Islands may see typhoon force winds around September 1. No major earthquakes are expected with this storm but moderate increases in seismicity in southeaster Japan are likely in the next three days." (August 28-29, 2017)

 

and

 

"TS Sanvu continued today over the Izu Islands, Japan with winds up to 80 kts. It is expected to track to the north but not to reach Honshu. Areas if the Volcano Islands north to the Izu Islands may see typhoon force winds around September 1. No major earthquakes are expected with this storm but moderate increases in seismicity in southeastern Japan are likely in the next three days." (September 3, 2017)

 

The last earthquake with M>=5.6 within about 200 km of this event in the Mariana and Volcano Islands occurred on December 14, 2016 (M 5.0). Forecast 110181 had expected an earthquake with magnitude up to M 5.6 was likely in the Volcano Islands in this area around September 3.

 

O:  4SEP2017 04:43:29  21.6N  143.0E Mw=5.6  EMSC   MARIANA ISLANDS REGION       

P:  3SEP2017 110181    23.0N  143.0E 4.0-5.6 ABAAA  Volcano Islands  

 

M 5.3 IN IDAHO POSSIBLY PROMOTED BY SOLAR ECLIPSE

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 2, 2017

 

A moderate M 5.3 occurred in the area of Idaho today and was preceded by an M 4.3 foreshock and a number of light to moderate aftershocks. This epicenter was within a few km of seeing the total eclipse of the sun which occurred on August 21. Tidal stresses from that event probably helped lead to today's earthquakes as was noted in this summary on August 21:

 

"Light earthquakes along or near the eclipse path occurred as an M 3.6 in western Montana; an M 3.2 in Yellowstone, Montana ....  In many cases seismicity promoted by tidal stresses with eclipses can indicate areas where stronger earthquake are likely with the next full or new moons. Monitoring of seismicity at this time can, therefore, help determine the locations of future felt or damaging earthquakes." (August 21, 2017)

 

The full moon of September 6 will just miss a partial lunar eclipse such as occurred at the last full moon on August 7 in the south Indian Ocean. Tidal stresses will be high, however and will maximize near the longitude of Southern Idaho as noted in this summary:

 

"The full moon will arrive on September 6 at 07:03 UT. Longitudes which are antisolar at this time (local solar midnight) are near 110 West while those which are subsolar (local solar noon) are near 70 East longitude. These include areas of the Rocky Mountains and western Mexico in the west and central Asia in the east. It is in these regions where the highest probability of tidal triggering exists for the next week. Many areas can, however, see enhanced seismicity due to earth tides associated with the full moon and are not exclusive to these longitudes." (September 2-3, 2017)

 

A further promoter to today's Idaho quake may have been seismic energy from an M 5.7 north of Guam, Mariana Islands. The Idaho quake occurs at the fourth node (90 degrees) from Guam and the surface wave from Guam arrived in Idaho about 10 minutes before that rupture initiated. SKSPPP core reflections were in Idaho at the time of the rupture and may have been the final straw.

 

NEIC reported the mainshock of M 5.3 was felt with intensity IV in Idaho at Soda Springs, Grace, Montpelier, Bern, Geneva, Bancroft, Paris, Idaho Falls, in Clarkston, Utah   and at Auburn and Grover, Wyoming. Communities within about 100 km of the epicenter reported the quake with intensity II-III. These included, among others, Smithfield, Clarkston, Trenton, Richmond, Lewiston, Utah; Pocatello, Franklin, McCammon, Preston, Lava Hot Springs, Idaho and Thayne, Bedford, Afton, Wyoming. NEIC received felt reports from as far as Walla Walla, Washington and Colorado Springs, Colorado nearly 700 km from the epicenter, but these are probably in error. The larger aftershocks were reported felt in northern Utah at Ogden and Brigham City with light intensity (II). Moderate aftershocks of M 4.1 were reported with intensity II-III in Pocatello and Soda Springs, Idaho, and II-III in Wyoming at Grover and Etna and in Utah at Garden City, Smithfield, Tremonton, Brigham City and Ogden.    The foreshock of M 4.3 about a minute before the M 5.3 was felt with intensity II-III in Pocatello, Idaho; and Thayne, Wyoming. Nearby foreshocks occurred with M 3.4 on February 6, 2017, the strongest earthquake in Idaho to this time in 2017 and on May 8, 2017 with M 2.7. A similar M 5.3 occurred about 30 km to the north of this on April 21, 2001, the only such event within about 100 km of this epicenter of M>=5.3 in at least the past 25 years. The last earthquake of M>=5.3 in the area was an M 6.2 on March 28, 2916. Other earthquakes of M>=5.3 occurred on August 30, 1952 (M 5.8); March 12, 1934 (M 6.6) with aftershocks; October 6, 1909 (M 6.3) and November 10, 1884 (M 6.3).   Forecast 110283 had expected a moderate quake in late August or early September within about 25 km of today's epicenter was possible. These events are located at the seventh node (51-52 degrees) from the M 7.7 in the Komandorsky Islands of July 17. and were probably promoted by energy from that source, the latest major earthquake in the world.

 

O:  3SEP2017 01:13:55  42.0N  111.8W ML=3.0  EMSC   UTAH                         

O:  3SEP2017 01:38:13  42.6N  111.4W ML=2.9  EMSC   SOUTHERN IDAHO               

O:  3SEP2017 00:38:14  42.6N  111.4W ML=3.1  EMSC   SOUTHERN IDAHO               

O:  3SEP2017 01:01:59  42.6N  111.4W ML=3.5  EMSC   SOUTHERN IDAHO               

O:  2SEP2017 23:55:30  42.6N  111.4W mb=4.3  EMSC   SOUTHERN IDAHO               

O:  3SEP2017 01:21:22  42.6N  111.5W ML=2.7  EMSC   SOUTHERN IDAHO               

O:  3SEP2017 02:11:37  42.6N  111.5W ML=2.8  EMSC   SOUTHERN IDAHO               

O:  3SEP2017 01:10:37  42.6N  111.5W ML=3.0  EMSC   SOUTHERN IDAHO               

O:  3SEP2017 00:05:29  42.6N  111.5W ML=3.1  EMSC   SOUTHERN IDAHO               

O:  3SEP2017 00:44:39  42.6N  111.5W ML=3.2  EMSC   SOUTHERN IDAHO               

O:  3SEP2017 00:39:48  42.6N  111.5W mb=4.1  EMSC   SOUTHERN IDAHO               

O:  3SEP2017 02:29:23  42.6N  111.5W mb=4.2  EMSC   SOUTHERN IDAHO                

O:  2SEP2017 23:56:58  42.7N  111.3W Mw=5.3  EMSC   SOUTHERN IDAHO               

O:  3SEP2017 01:27:58  42.7N  111.4W ML=2.8  EMSC   SOUTHERN IDAHO               

O:  3SEP2017 01:16:46  42.7N  111.4W ML=3.1  EMSC   SOUTHERN IDAHO                

O:  3SEP2017 00:07:14  42.7N  111.4W ML=3.2  EMSC   SOUTHERN IDAHO               

O:  3SEP2017 00:17:13  42.7N  111.5W ML=3.7  EMSC   SOUTHERN IDAHO               

P:  8SEP2017 110283    43.0N  111.5W 2.0-4.1 BAAAA  Yellowstone/Wyoming        

 

 

The earthquake in Guam may have been promoted by a C7.7 solar flare (#5610), the strongest in two weeks,  which occurred earlier in the day while Guam was near solar midnight, a prime time for immediate solar flare effects to promote seismicity. A smaller flare of C1.5 was observed by SWPC several minutes before the Guam earthquake and may also have helped promote this event on the geomagnetic equator. Because of this location, Guam often sees seismicity promoted by solar flares. The current geomagnetic storm also reached maximum today around 1500 UT, near midnight in Guam and may have also promoted seismicity there. Guam has seen several moderate foreshocks to today's earthquake which were probably related to the passage and formation of Typhoon Sanvu as noted in previous summaries:

 

"A series of moderate earthquakes also occurred in the region of Guam today with M 5.2 and 4.8 among others. These had been preceded by the formation of TS Sanvu over Guam three days ago." (August 30, 2017)

 

The last earthquake of M>=5.7 in Guam or the Rota region within about 200 km of this epicenter occurred on September 17, 2014 with M 6.7. That event was associated with Typhoon Kalmaegi. In this summary at the time

the association of Guam seismicity and tropical cyclones had been noted as follows:

 

"Seismicity in the region of Guam is often activated by strong storms in that region. This results in a tendency for local seismicity to concentrate in summer months. The largest recent earthquakes in the area occurred in late July, 2011 (M 5.6, 5.6); July and August, 2010 (M 5.5, 5.5). In the past 20 years 128 earthquakes of M>=5.3 have hit near Guam. Of these 45, nearly a third have occurred in the summer months of July, August and September while only about 30 would have been expected by chance." (July 27, 2013, August 13, 2014)

 

 

Forecast 109927 had expected activity in this region with a possibly moderately large event at the end of August or in early September.

 

O:  2SEP2017 23:00:01  14.0N  146.6E Mw=5.7  EMSC   ROTA REGION, N. MARIANA ISLAND

O:  3SEP2017 02:02:32  14.1N  146.8E mb=4.8  EMSC   ROTA REGION, N. MARIANA ISLAND

P: 28AUG2017 109927    16.0N  145.0E 4.0-5.5 BBBAA  No. Marianas               

 

A pair of earthquakes of M 4.5 and 4.4 occurred in Ecuador today. This may be related to antipodal triggering from the M 6.4 in Mentawai, Sumatra, Indonesia of August 31. Readers can confirm the antipodal nature of these events recalling that epicenter are antipodal if their latitudes are similar and in opposite

hemispheres (compare 1N and 1S) and their longitudes, in different hemispheres add numerically to 180 (Compare 99.8E and 80.2W longitudes). This summary had expected the occurrence of this activity in Ecuador at this time as:

 

"This epicenter is at the antipode of the major earthquake and aftershocks in Ecuador beginning with an M 7.8 on April 16, 2016 and may have been promoted following that activity. A possible triggered earthquake in the region of Ecuador or Colombia may occur in the next three days. As this area is in seismic shadow following the M 7.8 of April, 2016, however, such an event is unlikely to be large." (September 1, 2017)

 

Forecast 110120 had expected this activity in Ecuador around September 2.

 

   31AUG2017 17:06:58   1.1S   99.8E Mw=6.4  EMSC   KEP. MENTAWAI REGION, INDONESI

 

O:  3SEP2017 00:27:52   0.7N   80.2W mb=4.5  EMSC   NEAR COAST OF ECUADOR        

O:  3SEP2017 00:26:40   0.7N   80.3W mb=4.4  EMSC   NEAR COAST OF ECUADOR        

P:  2SEP2017 110120     2.0N   85.0W 4.0-5.8 ABCAA  So. of Panama               

 

As this summary was going to press, an M 5.6 earthquake was reported in North Korea. This is much larger than previous nuclear tests in the area and could indicate a new explosive device. This is certainly a nuclear test as it occurred at a shallow depth of 2 km at a time (almost exactly local noon) suggesting it was controlled.

 

NUSUAL M 5.7 IN THE REYKJANES RIDGE

 

EARTHQUAKE SUMMARY FOR SEPTEMBER 1, 2017

 

A strong series of earthquakes hit the region of the Reykjanes Ridge in the Northern mid-Atlantic today. The largest of these was an M 5.7 but it was associated with moderate foreshocks and aftershocks. This is a remote, active area of the Northern mid-Atlantic Ridge but earthquakes in the area are seldom felt. The strongest earthquakes within about 200 km of these epicenters in the past 25 years have been M 5.7 - on January 18, 2005 and October 7, 2002. No larger earthquakes have hit this area in the past 25 years. Forecast 110298 had expected this activity was likely within about 100 km of this epicenter was likely around September 1. Remnants of Tropical Storm  lingered in the area at the time of this series, but the current geomagnetic storm seems more likely to be a prime promoter of this series. These earthquakes are at the sixth node (60 degrees) from the M 6.7 quakes in Guatemala of June, 2017 and from the mid-Atlantic event of M 6.7 of August 18 and may have been promoted from those sources.

 

O:  1SEP2017 09:34:31  56.9N   34.3W mb=4.7  EMSC   REYKJANES RIDGE              

O:  1SEP2017 10:59:40  57.0N   34.0W mb=4.9  EMSC   REYKJANES RIDGE              

O:  1SEP2017 11:11:50  57.1N   33.9W mb=4.8  EMSC   REYKJANES RIDGE              

O:  1SEP2017 11:20:57  57.1N   34.0W Mw=4.9  EMSC   REYKJANES RIDGE              

O:  1SEP2017 11:07:38  57.1N   34.0W Mw=5.7  EMSC   REYKJANES RIDGE              

O:  1SEP2017 10:37:34  57.1N   34.0W mb=4.5  EMSC   REYKJANES RIDGE              

P:  1SEP2017 110298    58.0N   32.0W 4.0-5.6 AAAAA  North Mid-Atlantic Ridge   

 

The strongest felt earthquake today was an M 5.3 in the region of Costa Rica. NEIC reported it was felt with maximum intensity V in Samara, Guanacaste, Costa Rica and IV in Nandayure, Filadeldia, Liberia, and Paquera. Intensity II-III was reported within about 100 km of the epicenter at Fortuna, Venado, Tilaran, Juntas, Belen, Sardinal and other communities. No damage was reported.

The last earthquake in Costa Rica of M>=5.3 was an M 5.3 on April 2 about 300 km to the northwest of today's epicenter. The last of M>=5.3 within about 200 km of this epicenter was an M 5.3 on July 3, 2016 and prior to that an M 5.7 on December 31, 2015. Forecasts 109925 and 109907 expected today's event was likely at the end of August. This epicenter is located at node 5 (72 degrees) from the M 6.7 in the central mid-Atlantic of August 18 and may have been promoted by that event.

 

O:  1SEP2017 07:42:43  10.1N   85.6W Mw=5.3  EMSC   COSTA RICA                   

P: 29AUG2017 109925    11.0N   86.0W 3.5-5.3 AAAAA  Nicaragua                  

P: 30AUG2017 109907    10.0N   84.0W 3.5-5.1 AABAA  Caribbean Sea              

 

An earthquake of M 4.9 in the Dodecanese Islands of Greece was reported felt with intensity II-III in that area at Lardos, Masari, Afantou, Falirakion, Ialosos, Rodos, Karpathos, Kos, Iraklion and in western Turkey at

Felahiye, Koycegiz, Dalaman, and Datca. Although about 150 km southeast of the M 6.7 of July 20, this appears to be a regional aftershocks of that event.

Forecast 110237 had expected this earthquake was likely around September 6.

 

 

O:  1SEP2017 16:48:33  35.9N   28.1E mb=5.0  EMSC   EASTERN MEDITERRANEAN SEA    

O: 01SEP2017 16:48:34  36.0N   28.0E mw=4.9  ANSS   S of Lardos Greece

P:  6SEP2017 110237    37.0N   28.0E 3.5-4.9 BAAAA  Turkey                     

 

The strongest earthquake in the U.S. or Canada today occurred as an M 4.0 in Central Alaska. The last earthquake within about 100 km of this epicenter with M>=4.0 occurred on August 31, 2017 with M 4.9.  This event is probably an aftershock of that earthquake. Forecast 110056 expected today's event was likely within about 50 km of this epicenter in late August or early September.

 

O:  1SEP2017 03:21:20  63.0N  151.0W ML=4.0  EMSC   CENTRAL ALASKA               

P: 28AUG2017 110056    62.7N  150.6W 3.2-4.9 BAAAA  Central Alaska