STRONG EARTHQUAKE IN FIJI CONTINUES GEOMAGNETIC TRIGGERING

 

EARTHQUAKE SUMMARY FOR AUGUST 18, 2017

 

The strongest earthquake of the day was an M 6.4 in the Fiji Islands. This event occurred at the tail end of a solar flare of C4+ class which began about 30 minutes earlier. This flare is the strongest in more than a month - since a C5.8 class event of July 15, 2017. As today's event occurred within a few  degrees of the geomagnetic equator at deep focus, it is likely, like the Atlantic M 6.6 yesterday, it was promoted by this and other flare activity which began late on August 18 (UT). This had been expected in the previous summary as:

 

"This is the strongest geomagnetic storm since AP reached 51 on May 28 with high latitude AP of 84. With the new moon, this storm could activate a number of moderate to strong earthquakes. These would most likely occur near the geomagnetic equator expanding outwards over the next five days to 10-15 degrees from the equator. Some increases in event magnitude at high latitudes is also expected through August 24." (August 18, 2017)

 

While a strong M 7.0 quake hit the area about 500 km southwest of today's epicenter on January 3, 2017 and again on February 24, 2017 an equal distance to the south with M 6.9, this is the strongest event within about 250 km of this epicenter with M>=6.4 since an M 6.9 on September 24, 2016 and prior to that an M 7.1 on November 1, 2014, both about 200 km south of this epicenter. The last nearer such event occurred as an M 6.4 on April 3, 2011. Forecasts 109844 and 110082 had expected this event within about 100 km of the epicenter was likely between August 18 and 22. This epicenter is at the fifth node (72 degrees) from the M 7.7 in the Komandorsky Islands of July 17 and  may have been promoted from that source.

 

O: 19AUG2017 02:00:51  17.9S  178.8W Mw=6.4  EMSC   FIJI REGION                  

O: 19AUG2017 02:00:52  18.0S  178.9W mw=6.4  ANSS   SE of Lambasa Fiji

P: 18AUG2017 109844    17.0S  179.0W 4.0-5.5 AAAAA  Tonga Islands              

P: 22AUG2017 110082    18.0S  180.0W 4.0-5.8 BAAAA  Tonga Islands              

 

An earthquake of M 4.8 hit the region of Puerto Rico today. NEIC reported it was felt with maximum intensity IV in Puerto Rico at San German, Yauco, Penuelas, Caguas, Canovanas, Trujillo Alto, Carolina, Bayamon (V), San Juan, Arecibo, Fort Buchanan, Guaynabo, and in general within about 100 km of the epicenter. Heightened seismicity had been expected for Puerto Rico at this time. In the August 15, 2017 report for example, it was noted:

 

"An unusually large M 4.4-4.6 earthquake, also possibly related to stresses from Hurricane Gert was also located, but not reported felt, in Puerto Rico and the U.S. Virgin Islands today. At M 4.6 or M 4.4 this event is the strongest in the Puerto Rico area since an M 4.7 on July 17, 2017 and the second largest in the Puerto Rico area this year. Forecast 109677 had expected  this event was likely within about 100 km of this epicenter around August 15. Some of the great earthquakes in the Puerto Rico Trench have occurred in mid-August so there is some increased danger at this time for the region of the long-overdue great quake. Seismic effects from Hurricane Gert in this area had been anticipated in this summary as early as August 11 as:" (August 15, 2017)

 

"A system is currently northeast of the Virgin Islands at 21N 63W and tracking to the Leeward Islands and could help trigger a moderate earthquake in this area where seismicity has been occurring in recent weeks." (August 11, 2017)

 

The last earthquake in Puerto Rico with M>=4.9 was an M 6.4 on January 13, 2014 and prior to that an M 5.3 on December 17, 2011.   Forecast 109931 had expected today's moderate event was likely around August 22.

 

O: 18AUG2017 20:12:57  18.9N   66.6W mb=4.9  EMSC   PUERTO RICO REGION           

P: 22AUG2017 109931    18.0N   67.0W 3.4-5.0 AAAAA  Puerto Rico                

 

The strongest earthquake in the U.S. or Canada was an M 3.3 in the area of the Grise Fiord in northern Canada. This is a remote area and this event may be related to unloading of ice in the area at the end of summer. The last earthquake within about 250 km of this epicenter reported by NRCA with M>=3.3 was an 4.6 on November 9, 2014 about 200 km west of today's epicenter. Similar events occurred on November 26, 2012 and January 7, 2002. Forecast 109830 had expected a regional event was possible around August 19.  

 

O: 18AUG2017 07:06:51  76.4N   88.4W ML=3.3  NRCA  145 km W from Grise Fiord     

O: 18AUG2017 07:06:51  76.4N   88.4W ML=3.3  NRCA  145 km W from Grise Fiord     

P: 19AUG2017 109830    80.0N   90.0W 4.0-5.4 ACAAA  Arctic Ocean Region        

 

The most widely felt earthquake in the U.S. today was an M 3.2 in southeastern Missouri in the New Madrid Fault zone.  This earthquake of M 3.2 was widely felt in the New Madrid region of Missouri and Tennessee today. NEIC reported maximum intensity V in Marston, Missouri and IV in New Madrid, Missouri. Lesser shaking of intensity II-III was felt in Missouri at Portageville, Wardell, Perryville, Saint Louis; in Arkansas at Little Rock, Pine Bluff, Paragould; also felt in Paducah Kentucky, in Tennessee at Cordova, Tiptonville, and possibly in Oak Grove, Louisiana. This is the strongest earthquake within the region this year. The last earthquake in the area of southeastern Missouri with M>=3.2 was an M 3.4 on September 9, 2016 and prior to that an M 3.3 on June 17, 2012. Earthquakes in Tennessee about 75 km northeast of this epicenter occurred on May 16, 2017 (M 3.3) and March 15, 2017 (M 3.6). Forecast 109721 had expected this event within about 10 km of the epicenter was likely around August 17. The coincidence of today's event with the solar eclipse two days away suggests stresses related to that event may have helped promote today's earthquake as suggested in previous issues of this summary:

 

"The greatest eclipse will occur over the New Madrid Fault in Missouri and Tennessee. A moderate earthquake is possible in this area in the period August 18-25." (August 17-18, 2017)

 

O: 18AUG2017 15:18:21  36.5N   89.6W MD=3.2  EMSC   SOUTHEASTERN MISSOURI        

O: 18AUG2017 15:18:21  36.4N   89.6W md=3.2  ANSS   ENE of Portageville Missouri

P: 17AUG2017 109721    36.5N   89.6W 2.0-4.1 AAAAA  New Madrid area            

 

An equally unlikely earthquake to the New Madrid event occurred today with M 2.4 in the area of Dover, Arkansas. It was not reported felt in the epicentral area. The last event of M>=2.4 within about 50 km of this epicenter occurred on  M 2.9 on July 28, 2016. Forecast 109751 had expected this earthquake was likely around August 21.

 

O: 18AUG2017 12:49:57  35.4N   93.1W MD=2.4  EMSC   ARKANSAS                     

O: 18AUG2017 12:49:57  35.4N   93.1W md=2.4  ANSS   4km NE of Dover

P: 21AUG2017 109751    34.0N   93.0W 2.0-4.1 BBAAA  Southeast U.S.             

 

 

STRONG QUAKE UNDER CENTRAL ATLANTIC LIKELY PROMOTED BY GEOMAGNETIC STORM

 

EARTHQUAKE SUMMARY FOR AUGUST 17, 2017

 

The strongest earthquake in the world today was an M 6.6-6.7 north of Ascension Island in the central Atlantic. It was not reported felt in this remote epicentral area. It occurred on the geomagnetic equator at the height of the strongest geomagnetic storm in three months, since May 28 and was probably triggered by effects from this storm. A series of tropical waves and storms is beginning across the Atlantic as well with one very near the epicenter of today's earthquake, possibly influencing the timing of this event. The new geomagnetic storm and tropical cyclones across the Atlantic are likely to reset the global seismic map encouraging more seismicity in the regions of the Atlantic, the Caribbean and Central and North America in the next several weeks.

 

The geomagnetic field was at minor storm conditions today.  The AP level was 29.

High latitude geomagnetic field also saw stormy  conditions with AP at 59. This is the strongest geomagnetic storm since AP reached 51 on May 28 with high latitude AP of 84. With the new moon, this storm could activate a number of moderate to strong earthquakes. These would most likely occur near the geomagnetic equator expanding outwards over the next five days to 10-15 degrees from the equator. Some increases in event magnitude at high latitudes is also expected through August 24. The M 6.7 in the mid-Atlantic occurred at the height of this storm on the equator and was probably promoted by it.

 

No earthquakes of M>=5.5 have been recorded within about 250 km of this Atlantic epicenter during 2017. The last earthquake within this distance of the epicenter with M>=6.6 was an M 6.6 on February 18, 1996. The only event in the region in the past 25 years of larger magnitude was an M 6.9 on August 28, 1992. Forecast 109634 had expected this earthquake was likely about 200 km to the west around August 14. Areas at 103 degrees from this epicenter include much of the area from Central California north to Oregon and Washington and Southeast Alaska. These regions were active following this Atlantic event and may be expected to show some triggered activity in the next several days.  In particular, the area of Central California, including San Francisco, has had a flurry of small events over the past week and may be due for a larger triggered earthquake with the eclipse and effects from the Atlantic event today. This epicenter is near the seventh node from the events in western Turkey and the Dodecanese Islands, Greece of July 20 (M 6.7) and may have been influenced by energy from those events.

 

O: 18AUG2017 02:59:25   1.2S   13.7W Mw=6.6  EMSC   NORTH OF ASCENSION ISLAND    

O: 18AUG2017 02:59:21   1.1S   13.6W mw=6.6  ANSS   North of Ascension Island"

O: 17AUG2017 08:52:24   5.7S   12.5W mb=5.1  EMSC   ASCENSION ISLAND REGION      

P: 14AUG2017 109634     1.0S   16.0W 4.0-5.6 BABAA  Central Mid-Atlantic       

 

The most widely felt earthquake in the U.S. or Canada today was an M 4.0 in southeastern Alaska. NEIC reported it was felt with maximum intensity IV in Hoonah, Alaska and II-III in Gustavus, Haines, Skagway, Elfin Cove, Douglas, Juneau, Whitehorse and Angoon, Alaska. This is an aftershock of the two events of M 6.2 on May 1, the strongest such aftershock since May 21 when an M 4.3 occurred. Forecast 109812 had expected this event was likely within about 100 km of the epicenters around August 19.

 

O: 18AUG2017 04:44:36  59.0N  136.4W ML=4.0  EMSC   SOUTHEASTERN ALASKA           

P: 19AUG2017 109812    59.0N  138.0W 3.0-4.4 AAAAA  Southeast Alaska           

 

An earthquake of M 4.9 also occurred today in the Rat Islands, Alaska. It occurred near local solar noon a time when tidal stresses are high and may have been  promoted by them. This is the strongest earthquake in the Rat Islands since an M 5.0 on June 21. Forecast 109809 had expected this event within about 50 km  of this epicenter was likely around August 18.

 

O: 18AUG2017 01:17:00  51.3N  178.8E mb=4.9  EMSC   RAT ISLANDS, ALEUTIAN ISLANDS

P: 18AUG2017 109809    52.0N  179.0E 4.0-5.6 AAAAA  Rat Islands                

 

An unusually large M 4.2 earthquake hit the area of Lisbon, Portugal today. NEIC reported it was felt with intensity II-III in Carregado, Castanheira de Ribatejo, Milharado, Venda do Pinheiro, Ericeira, Lisbon, Estoril, Portugal. EMSC reported light to moderate intensity in Portugal at Alenquer, Carregado, Vila Franca de Xira, Sao Joao dos Montes, Alcoentre, Ramalhal, Alverca do Ribatejo, Torres Vedras, Salvaterra de Magos and other communities within about 50 km of the epicenter. This epicenter is near the antipode of strong earthquakes which have occurred in New Zealand recently. This summary has watched this region carefully because antipodal triggering was and is a distinct possibility following the New Zealand activity. The area is capable of great earthquakes such as the Lisbon quake of November 1, 1766 and more recently activity off the coast of M 8+ in the 1960's. These events can and do generate Atlantic-wide destructive tsunamis.

 

This is the strongest earthquake felt in mainland Portugal since an M 4.5 on December 29, 2005. The strongest earthquake within about 250 km of this in the past 25 years occurred in the Atlantic west of Portugal as an M 4.7 on May 26, 1990.  Forecast 109719 had expected this event within about 75 km of the epicenter was likely around August 21.

 

O: 17AUG2017 09:06:56  39.0N    9.1W ML=2.0  EMSC   PORTUGAL                     

O: 17AUG2017 06:44:56  39.0N    9.1W mb=4.2  ANSS   Arruda dos Vinhos Portugal

O: 17AUG2017 06:44:56  39.1N    9.0W mb=4.2  EMSC   PORTUGAL                     

P: 21AUG2017 109719    39.0N    8.0W 3.5-4.9 BAAAA  Morocco/Spain              

 

The full moon will arrive at 18:30 UT on August 21. Longitudes which are sub-solar at the time of full moon are near 97W and 83E and include the Central U.S. Mexico and Central America in the west and India, China, Afghanistan and western Indonesia in the east. These longitude zones are most likely to see significant tidal triggering within about three days of August 21. Other areas may also see tidal triggering at this time, especially where fluids mitigate seismicity and where vertical motions are common. The much-anticipated solar eclipse of August 21 will pass over much of the central U.S. and will be viewed by millions of people at this vacation time of year. The eclipse is the first to be visible over the entire U.S. in 99 years. The full eclipse will be  visible from the Pacific Northwest through Lincoln, Nebraska and into the  southeast of the U.S. Tidal triggering could occur in Washington, Oregon or Northern California with lesser triggering in the central and southeastern U.S. Like the full moon this will reach maximum when over 97 West longitude (83 East) with maximum effects in the regions of Oklahoma and Kansas. The greatest  eclipse will occur over the New Madrid Fault in Missouri and Tennessee. A  moderate earthquake is possible in this area in the period August 18-25. The M 6.7 in the Central Atlantic today would be at the end point of this eclipse path and may have been promoted by high tidal stresses.

 

An M 5.3 in Mexico today occurred in the state of Guerrero. The earthquake in Guerrero, Mexico today was felt with intensity II-III in Mexico City and Nezahualcoyoti, Mexico. This is the largest earthquake in Guerrero, Mexico during the year 2017. The last of M>=5.3 was an event of M 5.5 on November 23, 2015 and prior to that  an M 6.0 on May 10, 2014 - and aftershock of an M 7.2 on April 18, 2014.  Forecasts 109402 and 109674 had expected this event within about 25 km was likely between August 11 and 18.  This epicenter is at the fourth node from the Atlantic event (90 degrees) and may have been promoted from that source.

 

O: 18AUG2017 05:58:06  16.8N  100.4W ML=4.1  EMSC   OFFSHORE GUERRERO, MEXICO    

O: 17AUG2017 02:43:54  16.5N   99.0W ML=4.1  UNAM  l SURESTE de SAN MARCOS, GRO *: 16

O: 17AUG2017 16:03:21  16.9N   99.8W ML=4.0  UNAM   NORESTE de ACAPULCO, GRO *: 16.92

O: 18AUG2017 05:58:06  16.8N  100.4W ML=4.1  UNAM  l SUROESTE de COYUCA DE BENITEZ, G

O: 18AUG2017 05:15:11  16.8N  100.4W ML=5.3  UNAM  l SUR de ATOYAC DE ALVAREZ, GRO *:

O: 17AUG2017 16:03:21  16.9N   99.8W ML=4.0  EMSC   GUERRERO, MEXICO             

O: 18AUG2017 05:15:14  17.0N  100.3W mb=5.2  EMSC   GUERRERO, MEXICO             

P: 11AUG2017 109402    17.0N  100.0W 3.5-5.1 CAAAA  Oaxaca, Mexico             

P: 18AUG2017 109674    16.0N  100.0W 3.5-5.2 AAAAA  Oaxaca, Mexico             

 

MODERATELY STRONG QUAKE SHAKES RYUKYU ISLANDS, JAPAN

 

EARTHQUAKE SUMMARY FOR AUGUST 16, 2017

 

A moderately strong earthquake of M 5.7 was widely felt in the Ryukyu Islands of Japan today. NEIC reported it was felt with intensity II-III in Okinawa at Nago, Ishikawa, Yomitan, Gushikawa, Okinawa, Chatan, Ginowan, Urasoe,  and Nana, Japan. This is probably related to stresses from Typhoon Noru which passed over this epicenter last week. This level of activity in the Ryukyu Islands had been

expected at this time in this report:

 

Super -"Typhoon Noru continued today over Kyushu, Japan with winds up to 080 kts. It is expected to continue on the unusual track to the south of Honshu. Seismicity in the region of Kyushu, the Ryukyu Islands and Honshu may include a moderate to large event as Noru passes through the region." (August 7-10, 2017)

 

and

 

"... lessening of normal friction along the subduction zone under Honshu as the island rises with lessened atmospheric pressure load. Seismicity in the region of  Honshu may include a moderate to large event as Noru passes through the region. A moderate seismic watch for the area is in effect through August 11." (August 7-8, 2017)

 

Two earthquakes of M>=5.7 have hit the Ryukyu Islands during 2007 - an M 6.1 on May 9 and an M 5.9 on July 26 but none have occurred within 200 km of this epicenter this year. The last earthquake of M>=5.7 within about 200 km of this epicenter was an M 6.0 on September 26, 2016 and prior to that an M 5.8 on October 22, 2014.  Forecast 109691 had expected a moderate event in this region was likely around August 18.

 

O: 16AUG2017 12:51:24  28.8N  127.9E Mw=5.7  EMSC   NORTHWEST OF RYUKYU ISLANDS  

P: 18AUG2017 109691    27.0N  127.0E 4.0-5.4 ABAAA  Ryukyu Islands             

 

An M 3.6 in Hawaii today was felt with intensity III in Keaau, Honokaa and Kamuela, Hawaii. The last event in Hawaii of M>=3.6 was an M 4.2 on July 30, 2017. Forecast 109662 expected a moderate event in Hawaii was likely around August 18.

 

NEIC reported an earthquake of M 2.9 in Hawaii was also felt with intensity II-III in the area(s) of Ookala, Laupahoehoe, Honokaa, Pepeekeo, Paauilo, Kamuela, and Princeville, Hawaii.

 

O: 16AUG2017 13:53:42  19.9N  154.6W ML=3.6  EMSC   HAWAII REGION, HAWAII        

O: 16AUG2017 13:53:42  19.9N  154.6W ml=3.6  ANSS   Hawaiian Paradise Park Hawaii

O: 16AUG2017 15:24:03  20.1N  155.3W ML=2.9  EMSC   HAWAII REGION, HAWAII        

P: 18AUG2017 109662    18.8N  155.2W 3.0-4.6 AAAAA  Hawaii                     

 

 

MODERATE QUAKES IN CHILE AND SUMATRA RELATED TO TIDAL STRESSES

 

EARTHQUAKE SUMMARY FOR AUGUST 15, 2017

 

Moderate earthquakes of M 5.5 in Central Chile and of M 5.4 in Sumatra, Indonesia today occurred at times and locations suggestive of tidal promotion. The strongest of these - the M 5.5 in Central Chile occurred within several hours of local solar noon, a time when tidal stresses are maximized. The other event in  Mentawai, Sumatra occurred at a longitude where tidal stresses associated with the full and upcoming new moon are greatest as noted in previous summaries:

 

 

"The full moon arrived at 18:11 UT on August 7. Longitudes which were sub-solar at the time of full moon are near 92W and 88E and include the Central U.S. Mexico and Central America in the west and India, China, Afghanistan and western Indonesia in the east. These longitude zones are most likely to see significant tidal triggering within about three days of August 7. Other areas may also see tidal triggering at this time, especially where fluids mitigate seismicity and where vertical motions are common. The much-anticipated solar eclipse of August 21 will pass over much of the central U.S. and will be viewed by millions of people at this vacation time of year. The full eclipse will be  visible from the Pacific Northwest through Lincoln, Nebraska and into the  southeast of the U.S. Tidal triggering could occur in Washington, Oregon or Northern California with lesser triggering in the central and southeastern U.S. Like the full moon this will reach maximum when over 97 West longitude (83 East) with maximum effects in the regions of Oklahoma and Kansas. The greatest  eclipse will occur over the New Madrid Fault in Missouri and Tennessee. A  moderate earthquake is possible in this area in the period August 18-25." (August 7-11, 2017)

 

The M 5.5 in Central Chile continued a string of moderately large to large events from Peru and Chile over the past week. An M 5.8 hit this region off the coast of Coquimbo on August 12 and this is probably an aftershock of that event. Forecasts 109862 and 109846 had expected a moderately large regional event was likely around August 16.

 

CSN reported this earthquake at M 5.3 was felt with intensity V in  La Serena; IV Vicuna, Coquimbo, III Ovalle, Rio Hurtado; II Andacollo, Felt in Coquimbo, Chile. NEIC reported this earthquake of M 5.1 in Chile was felt with intensity IV in Valparaiso and II-III in the area(s) of La Serena, Coquimbo, Quilpue, Villa Alemana and Santiago, Chile.

 

O: 15AUG2017 19:03:20  29.9S   72.2W Mw=5.5  EMSC   OFFSHORE COQUIMBO, CHILE     

O: 15AUG2017 19:03     30.0S   72.8W mb=5.3  GUC    La Serena; IV Vicuna, Coquimbo

P: 14AUG2017 109862    30.0S   69.0W 4.0-5.6 AACAA  Coast Central Chile        

P: 16AUG2017 109846    29.0S   68.0W 4.0-5.6 AACAA  Argentina                  

 

The M 5.4 in the Mentawai area of Indonesia is antipodal to northern Ecuador

(2N 80W) and may see a promoted event in that region in the next several days.

BMG reported it was felt with intensity III in Tuapejat, II-III in Padang, Painan, and I-II in Bukittinggi, Payakumbuh, Padang Panjang, and Sawah Lunto, Mentawai, Sumbar, Indonesia. A series of moderate to strong earthquakes in western Indonesia in the past week has included an M 6.4 in Sumatra. This may be a regional aftershock of that event. The last earthquakes of M>=5.4 within about 100 km of this epicenter were an M 6.6 on January 9, 2017 and an M 5.8 on August 24, 2016. Forecast 109648 had expected this earthquake within this region was likely  around August 20. This epicenter is at the fifth node (72 degrees) from the M 6.6 in the Auckland Islands region of New Zealand and may have been promoted from that source.

 

O: 16AUG2017 04:09:05   2.3S   99.9E mb=5.4  EMSC   KEP. MENTAWAI REGION, INDONESI

O: 16AUG2017 04:09:03  02.3S  099.8E MS=5.4  BMG  Felt with intensity III

P: 20AUG2017 109648     2.0S   99.0E 4.0-5.6 BAAAA  So. of Sumatera            

 

The strongest earthquake of the day was an M 5.7 in northern Tonga near Samoa. It was not reported felt. An M 5.6-5.7 hit Tonga on January 28 but this is the strongest event in Tonga since an M 6.1 on October 26, 2016. Forecast 109838 had expected today's earthquake within about 25 km of the epicenter was likely around August 18.  This epicenter is at the fifth node (72 degrees) from the M 7.7 in the Komandorsky Islands of July 17 and may have been promoted from that source.

 

O: 15AUG2017 06:01:47  15.1S  173.3W Mw=5.7  EMSC   TONGA                        

P: 18AUG2017 109838    15.0S  173.0W 4.0-5.5 BAAAA  Samoa Islands               

 

An earthquake of M 4.7 in Northern Algeria today was preceded by an M 3.9 foreshock. The mainshock was felt with maximum intensity up to V in Merouana and lesser shaking in N'Gaous, Batna, Ain Oulmene, and El Eulma, Algeria. An M 4.9 hit about 500 km west of this on July 11 but the last event within  about 250 km of this epicenter with M>=4.7 was an M 4.8 on March 21, 2015. Forecast 109758 had expected today's event in this region was likely around August 16. This epicenter is located at node 4 (90 degrees) from the M 7.7 Komandorsky Island earthquake of July 17 and may have been promoted from that source.

 

O: 15AUG2017 06:41:00  35.3N    4.9E ML=3.9  EMSC   NORTHERN ALGERIA             

O: 15AUG2017 14:50:43  35.6N    5.8E mb=4.7  EMSC   NORTHERN ALGERIA             

P: 16AUG2017 109758    37.0N    4.0E 3.0-4.6 ABAAA  Western Mediterranean      

 

Another moderate earthquake occurred along the northern Mid-Atlantic Ridge today. This event of M 4.8 is about 400 km to the southeast of the swarm which hit the area yesterday. It was not reported felt in this remote area. This is the strongest earthquake recorded within about 200 km of this epicenter with M>=4.8 since an M 5.0 on December 23, 2015. The largest event in the region in the past 25 years was an M 5.4 on November 21, 2003. Forecast 109779 had expected this earthquake was likely within about 50 km of this epicenter around August 18.

 

O: 16AUG2017 02:27:31  45.5N   27.9W mb=4.8  EMSC   NORTHERN MID-ATLANTIC RIDGE  

P: 18AUG2017 109779    45.0N   28.0W 4.0-5.6 AAAAA  No. Mid-Atlantic Ridge     

 

 

 

EARTHQUAKES IN SOUTH PACIFIC; PAPUA NEW GUINEA

 

EARTHQUAKE SUMMARY FOR AUGUST 14, 2017

 

Two moderately large earthquake occurred today. The largest of these was an M 5.6 in the Pacific-Antarctic Ridge and later in the day an M 5.5 in Papua New Guinea occurred. The event in the Pacific Antarctic Ridge was not reported felt in this remote epicentral area. The last event of M>=5.6 within about 250 km of this epicenter occurred as an M 6.0 on February 16, 2016 and prior to that on May 19, 2015 with M 6.7. 

 

O: 14AUG2017 05:35:11  55.3S  129.3W Mw=5.6  EMSC   PACIFIC-ANTARCTIC RIDGE      

 

The earthquake in Papua New Guinea of M 5.5 was not unusual.

BMG reported this earthquake was felt with intensity III in Keerom and II-III in Wamena and Jayapura, Papua New Guinea, Indonesia.  The last earthquake of M>=5.5 within about 250 km of this epicenter was an  M 5.6 on September 24, 2016. An M 7.0 occurred in thies region to the west of today's epicenter on July 27, 2015. 

 

O: 14AUG2017 23:49:30   3.8S  140.4E mb=5.5  EMSC   PAPUA, INDONESIA             

O: 14AUG2017 23:49:28  03.8S  140.5E MS=5.5  BMG  Felt with intensity III in Keerom and II-III in Wamena and Jayapura, Papua New Guinea, Indonesia.

P: 17AUG2017 109646     3.0S  140.0E 4.0-5.6 BAAAA  Papua New Guinea           

 

 

An earthquake in the general area of Tokyo, Japan of M 4.8 was widely felt in southeastern Japan today where it was felt with intensity up to IV at Tokyo, Komai, Musashino and Mitaka. NEIC reported intensity II-III in Chiba Prefecture at Narashino, Chiba, Ichikawa, Narita, Tomisato, Urayasu,  and in Ibaraki at Toride, Naka, Tsuchiura, Kawaguchi, Saitama, Ishige; in Saitama; in Kanagawa at Yokohama, Kawasaki, and in general within about 150 km of the epicenter.

Earlier in the day and to the north an M 4.9 was lightly felt in Akita and Yokosuka, Japan. This is probably a reaction to stresses from Typhoon Noru which passed north of this epicenter over the past two days and had been expected in this report to promote regional seismicity at this time as:

 

"... lessening of normal friction along the subduction zone under Honshu as the island rises with lessened atmospheric pressure load. Seismicity in the region of  Honshu may include a moderate to large event as Noru passes through the region.  A moderate seismic watch for the area is in effect through August 11." (August 7-8, 2017)

 

The earthquake today near Tokyo of M 4.8 was the first of this magnitude within about 100 km of Tokyo since an M 5.0 on August 10. An M 5.5 on February 19, 2017 is the strongest earthquake to occur this year in the area. Forecast 109728 had expected this event within about 100 km of this epicenter areound August 17.

 

O: 14AUG2017 09:11:33  35.8N  140.1E mb=4.8  EMSC   NEAR EAST COAST OF HONSHU, JAP

O: 14AUG2017 09:11:34  35.8N  140.1E mb=4.8  ANSS   ENE of Shiroi Japan

P: 17AUG2017 109728    35.0N  141.0E 4.0-5.4 BAAAA  Off East Coast Honshu      

 

O: 14AUG2017 03:06:00  39.6N  143.4E mb=4.9  EMSC   OFF EAST COAST OF HONSHU, JAPA

P: 12AUG2017 109768    40.0N  142.0E 3.5-5.6 AAAAA  Hokkaido, Japan            

 

 

An unusually large earthquake of M 2.7 (EMSC) to M 3.3 (NRCA) near Ottawa, Canada today was felt in the region. The last earthquake within about 100 km of this epicenter with M>=3.3 occurred on August 5, 2015 with M 3.5.  Forecast 109503 and 109777 had expected this activity within about 25 km of this epicenter was likely in early August.  NEIC reported this earthquake of M 2.7 in Quebec, Canada was felt with intensity II-III in the area(s) of Buckingham, Quebec; in Ontario at Bourget, Ottawa and Tweed; in Williston, Vermont, Cooperstown and Buffalo, New York. Earthquakes Canada gave this M 3.3 and noted it was lightly felt in Ottawa and the Outaouais region. This epicenter is located at the fifth node (72 degrees) from the activity continuing in Western Turkey and may be promoted by it.

 

O: 14AUG2017 20:58:36  45.7N   75.5W ML=3.3  NRCA  240 km NE of Ottawa, Canada   

O: 14AUG2017 20:58:34  45.7N   75.4W mb=2.7  EMSC   ONTARIO-QUEBEC BORD REG., CANA

O: 14AUG2017 20:58:34  45.7N   75.4W mb=2.7  ANSS   ENE of Val-des-Monts Canada

P:  6AUG2017 109503    45.7N   75.2W 2.0-4.1 CAAAA  New York State             

P: 13AUG2017 109777    46.0N   72.0W 2.0-4.1 AABAA  New England                

 

A strong series of earthquakes occurred in the Mammoth Lakes region of California today where events of M 3.4 and 3.5 were lightly felt. The only earthquakes in the year 2017 of M>=3.5 in the Mammoth Lakes region of California occurred on July 9 (M 3.9) and June 20, 2017 (M 3.5). There is some evidence that these events are reaching closer to the surface in the past year and may reflect magma motions beneath the area. This activity may also be a response to the passage of Hurricane Gert over the continental shelf and resulting motions of North America.  Forecast 109700 had expected a light to moderate earthquake in the Mammoth Lakes area around August 14.

 

O: 14AUG2017 10:37:41  37.5N  118.8W MD=2.0  EMSC   CENTRAL CALIFORNIA           

O: 14AUG2017 11:08:26  37.5N  118.8W MD=2.0  EMSC   CENTRAL CALIFORNIA           

O: 14AUG2017 07:55:42  37.5N  118.8W MD=2.1  EMSC   CENTRAL CALIFORNIA           

O: 14AUG2017 11:12:51  37.5N  118.8W MD=2.1  EMSC   CENTRAL CALIFORNIA           

O: 15AUG2017 04:50:22  37.5N  118.8W MD=2.1  EMSC   CENTRAL CALIFORNIA           

O: 14AUG2017 06:01:31  37.5N  118.8W MD=2.4  EMSC   CENTRAL CALIFORNIA           

O: 14AUG2017 06:21:40  37.5N  118.8W MD=2.5  EMSC   CENTRAL CALIFORNIA           

O: 14AUG2017 07:06:35  37.5N  118.8W MD=2.9  EMSC   CENTRAL CALIFORNIA           

O: 14AUG2017 08:02:05  37.5N  118.8W MD=2.9  EMSC   CENTRAL CALIFORNIA           

O: 14AUG2017 11:37:45  37.5N  118.8W ML=2.3  EMSC   CENTRAL CALIFORNIA           

O: 14AUG2017 08:47:39  37.5N  118.8W ML=3.4  EMSC   CENTRAL CALIFORNIA           

O: 14AUG2017 08:08:21  37.5N  118.8W ML=3.5  EMSC   CENTRAL CALIFORNIA           

P: 14AUG2017 109700    37.6N  118.7W 2.5-4.4 AAAAA  California/Nevada area     

 

An unusually large M 4.4-4.6 earthquake, also possibly related to stresses from Hurricane Gert was also located, but not reported felt, in Puerto Rico and the U.S. Virgin Islands today. At M 4.6 or M 4.4 this event is the strongest in the Puerto Rico area since an M 4.7 on July 17, 2017 and the second largest in the Puerto Rico area this year. Forecast 109677 had expected  this event was likely within about 100 km of this epicenter around August 15. Some of the great earthquakes in the Puerto Rico Trench have occurred in mid-August so there is some increased danger at this time for the region of the long-overdue great quake. Seismic effects from Hurricane Gert in this area had been anticipated

in this summary as early as August 11 as:

 

"A system is currently northeast of the Virgin Islands at 21N 63W and tracking to the Leeward Islands and could help trigger a moderate earthquake in this area where seismicity has been occurring in recent weeks." (August 11, 2017)

 

O: 14AUG2017 08:13:53  18.9N   65.3W MD=3.0  EMSC   PUERTO RICO REGION           

O: 14AUG2017 22:11:48  19.4N   65.0W md=4.4  ANSS   Amalie U.S. Virgin Islands

O: 14AUG2017 22:11:47  19.4N   65.3W mb=4.6  EMSC   PUERTO RICO REGION           

O: 14AUG2017 23:11:10  19.5N   65.2W MD=3.0  EMSC   PUERTO RICO REGION           

P: 15AUG2017 109677    19.0N   66.0W 3.4-5.1 AAAAA  Puerto Rico                

 

STRONG EARTHQUAKE IN CENTRAL PERU CONTINUES REGIONAL ACTIVATION

 

EARTHQUAKE SUMMARY FOR AUGUST 13, 2017

 

The strongest seismicity in the world today continued in the region of Peru. An M 5.6 (EMSC) to 6.1 (IGP) earthquake hit central Peru and was widely felt. This is a region which saw a moderate earthquake two days ago when a similar M 6.1 was recorded and widely felt in southern Peru.

 

IGP reported this earthquake was felt with intensity V in  Satipo, Pto. Bermudez, Villa Rica; IV La Merced, Atalaya, Oxapampa; III-IV Pto Inca, Huancayo, Pozuzo; III La Oroya, Cerro Pasco; II Huanuco, Huanta, Peru.

NEIC reported this earthquake of M 5.6 in Central Peru was felt with intensity V in Huancayo, Junin, Peru and II-III in the area(s) of Huanuco and Lima, Peru.  The last earthquake within about 250 km of this epicenter with M>=5.6 occurred on October 25, 2014.  No earthquakes of M>6 have been previously recorded in this area in the past 25 years. A major earthquake of M 7.5 hit about 400 km east of this epicenter at a deep focus of 611 km on November 24, 2015. This may have set the area upslope the subduction zone for the type of earthquake seen today. Forecast 109566 had expected this event was likely within about 100 km of the epicenter in early August. This epicenter is at 106 degrees from the series of events in Western Turkey and at 101 degrees from the Auckland, New Zealand event of July 11, distances at which concentrated energy from major events returns to the earth's surface and may help trigger additional seismicity.

 

O: 13AUG2017 16:51:23  10.7S   74.5W Mw=5.6  EMSC   CENTRAL PERU                 

O: 13AUG2017 16:51     10.8S   74.7W mb=6.1  IGP    Satipo, Pto. Bermudez, Villa R

P:  3AUG2017 109566    10.0S   75.0W 3.5-5.0 CAAAA  Brazil                      

 

Moderate earthquakes of M 4.9, 4.7 and M 4.4 were widely felt in western Turkey and the Dodecanese Islands of Greece today. The event of M 4.9 was reported felt in Izmir, Turkey with maximum intensity V and IV in Milas, Mugla, Turkey and Kos, Dodecanese Islands, Greece. This event was also felt in Greece with intensity II-III in Kardamaina, Simi, and Kos and in Turkey at Bodrum, Sultanbeyli, Marmaris. An M 4.7 was felt with maximum intensity at Milas, Mugla, Turkey and III in Bodrum and Marmaris, Turkey and in the Dodecanese Islands at Kos and Simi, Greece. A number of foreshocks and aftershocks occurred with M>4 which were felt in Turkey at Modrum, Mugla, Turkey. These are regional aftershocks of the M 6.7 which hit the Dodecanese Islands of July 20, but the series appears to be migrating to the north and east, perhaps signaling a major Anatolian Fault earthquake is near. The last event of M>=4.9 in this aftershocks sequence was an M 5.3 on  August 8, 2017. Forecasts 109754 and 109696 had expected moderate activity in the region around August 14-16.

 

O: 13AUG2017 16:31:22  37.1N   27.7E ML=4.0  EMSC   WESTERN TURKEY               

O: 13AUG2017 17:09:07  37.1N   27.7E ML=4.0  EMSC   WESTERN TURKEY               

O: 13AUG2017 12:28:15  37.1N   27.7E ML=4.2  EMSC   WESTERN TURKEY               

O: 13AUG2017 11:16:53  37.1N   27.7E ML=4.9  EMSC   WESTERN TURKEY               

O: 13AUG2017 16:35:23  37.1N   27.7E mb=4.4  EMSC   WESTERN TURKEY               

O: 14AUG2017 02:43:49  37.2N   27.6E mb=4.7  EMSC   WESTERN TURKEY               

P: 14AUG2017 109754    37.0N   28.0E 3.5-5.1 AAAAA  Turkey                     

P: 16AUG2017 109696    37.0N   27.0E 3.0-4.5 AAAAA  Aegean Sea                 

 

O: 13AUG2017 08:51:47  38.8N   27.8E ML=4.2  EMSC   WESTERN TURKEY               

P: 11AUG2017 109427    39.0N   27.0E 3.0-4.5 AAAAA  Aegean Sea                 

 

No significant (M>=5) or unusual earthquakes were reported in Europe today.

 

A strong series of earthquakes also occurred in the North Atlantic mid-Ocean Ridge today. This is an unusual location for moderate seismicity. A foreshock of M 5.0 occurred March 1, 2007 but the last of M>5.1 within about 200 km of these epicenters occurred on September 30, 2013 with M 5.4. The last within about 100 km of this epicenter was an M 5.7 on May 17, 2002. Forecast 109807 had expected a moderate earthquake was possible in this region of the North Atlantic around August 12. This activity is in the antipodal area of the M 6.6 South of New Zealand of July 11 and may have been promoted by focused energy from that event. A possible motivator for this series is Tropical Storm Gert which entered the North Atlantic today after encountering the continental slope earlier in the day.

 

O: 14AUG2017 00:43:51  48.7N   28.0W mb=4.5  EMSC   NORTHERN MID-ATLANTIC RIDGE  

O: 14AUG2017 00:24:45  48.7N   28.0W mb=4.9  EMSC   NORTHERN MID-ATLANTIC RIDGE  

O: 14AUG2017 00:54:48  48.8N   28.0W mb=4.5  EMSC   NORTHERN MID-ATLANTIC RIDGE  

O: 14AUG2017 00:29:04  48.8N   28.0W mb=5.0  EMSC   NORTHERN MID-ATLANTIC RIDGE  

O: 14AUG2017 00:19:19  48.9N   28.0W mb=4.8  EMSC   NORTHERN MID-ATLANTIC RIDGE  

O: 14AUG2017 00:29:04  48.7N   27.9W mb=5.1  ANSS   Northern Mid-Atlantic Ridge" 

P: 12AUG2017 109807    53.0N   32.0W 4.0-5.6 ACCAA  North Mid-Atlantic Ridge   

 

EMSC also shows a moderate M 5.2 in the middle of this swarm in the stable portion of the North Atlantic off Massachusetts. It is likely this is a  miscalculation of one of the events in the Mid-Atlantic, but needs to be confirmed by further calculation as this is a highly unlikely event.

 

O: 14AUG2017 00:26:37  43.4N   51.6W ML=5.2  EMSC   NORTH ATLANTIC OCEAN         

 

The strongest earthquake in the U.S. or Canada today was an M 4.6 in the Andreanof Islands of Alaska. It was not reported felt in this remote area. The last earthquake in the Andreanof Islands within about 100 km of today's epicenter with M>=4.6 occurred on April 4 with M 5.6 and aftershocks. Forecast 109799 had expected this event within about 50 km of the epicenter was likely around August 12.

 

O: 13AUG2017 23:24:30  51.9N  176.8W mb=4.6  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P: 12AUG2017 109799    51.6N  177.6W 3.5-5.1 AAAAA  Andreanoff Isls, Aleutians 

 

 

STRONG EARTHQUAKE IN SUMATRA CONTINUES TIDAL PATTERN

 

EARTHQUAKE SUMMARY FOR AUGUST 12, 2017

 

A strong earthquake of M 6.4-6.6 hit the region of Bengkulu, Sumatra today. NEIC reported maximum intensity IV in Bengkulu, Curup and Padang, Sumatra with intensity II-III felt in Sumatra at Pagar Alam, and as far as Singapore and Johor Bahru and Sekudai, Malaysia more then 600 km from the epicenter.

BMG reported the event at M 6.6 was felt with intensity V in Bengkulu, Kepahiang and Bengkulu Utara; IV in Lubuk linggau, Kerinci, Bengkulu Selatan, Liwas; II-III in Padang, Pariaman, Tua Pejat, Mentawai and Pesisir Selatan; and I-II in Padang Panjang, Bukit Tinggi, Payakumbuh, Solok and Solok Selatan, Bengkulu, Indonesia. This event which occurred near local solar noon, was probably promoted by strong tidal stresses associated with the full moon. Large earthquakes have been prominent in eastern Asia since the full moon and have included events of M 6.0-6.5 in in Sichuan and Xinjiang, China, Mindoro, Philippines and today's Sumatran event. The tidal forecast for seismicity associated with this full moon had expected this pattern as:

 

 

"The full moon will arrive at 18:11 UT on August 7. Longitudes which are sub-solar at the time of full moon are near 92W and 88E and include the Central U.S. Mexico and Central America in the west and India, China, Afghanistan and WESTERN INDONESIA (Emphasis added) in the east. These longitude zones are most likely to see significant tidal triggering within about three days of August 7. Other areas may also see tidal triggering at this time, especially where fluids mitigate seismicity and where vertical motions are common." (August 5-7, 2017)

 

A small local tsunami is possible but was not reported with this earthquake. The last earthquake within about 200 km of this epicenter in Bengkulu, Indonesia with M>=6.4 occurred on June 1, 2016 with M 6.5 about 250 km northwe4st of today's epicenter. An M 7.8 hit the Bengkulu area on October 25, 2010 but the area has been in seismic shadow (with exception of the June, 2016 event) since that time. Forecast 109383 had expected a moderately strong earthquake was possible in this area south of Sumatra around August 8. The distance between the Sumatra quake and an earlier M 5.8 in Coquimbo, Chile is 145 degrees, a distance at which seismic triggering is deemed likely from concentrated seismic energy returning to the surface.

 

O: 13AUG2017 03:08:11   3.8S  101.6E mw=6.4  ANSS   W of Bengkulu Indonesia

O: 12AUG2017 03:08:10  03.8S  101.6E MS=6.6  BMG  Felt with intensity V

O: 13AUG2017 03:08:13   3.6S  101.7E Mw=6.4  EMSC   SOUTHERN SUMATRA, INDONESIA  

P:  8AUG2017 109373     5.0S  102.0E 4.0-5.6 BBAAA  So. of Sumatera            

 

The antipode of today's earthquake is at 4N 79W an area of western Colombia north of Ecuador. Antipodal seismicity is common in these two areas and this region could see a moderate to large earthquake in the next week.

 

An M 5.8 in the area of central Chile near Coquimbo also occurred today. This is in the antipodal area of the M 6.5 event in Sichuan, China which occurred with the full moon on August 8 at 33N 104E (compare with 30S 72W). NEIC reported this earthquake was felt with maximum intensity IV in Vicuna, Coquimbo and II-III in La Serena, Valparaiso, Chile and Mar del Plata, Buenos Aires, Argentina. CSN reported this earthquake was felt with intensity IV in  La Serena, III Vallenar, Coquimbo, Paihuano; II Copiapo, Felt in Atacama, Coquimbo, Chile. The last earthquake of M>=5.8 in the Coquimbo aftershocks zone was an M 6.3 on February 10, 2016. The area saw a strong series of events in 2015 following an M 8.3 on September 16, 2015 south of this epicenter but has been in seismic shadow from that event since early 2016. Forecast 109862 had expected this area could see a moderately large event around August 14.

 

O: 12AUG2017 12:54     30.3S   72.2W mb=5.7  GUC    La Serena, III Vallenar, Coqui

O: 12AUG2017 12:54:12  30.2S   72.3W mw=5.8  ANSS   WSW of Coquimbo Chile

O: 12AUG2017 21:31:18  30.3S   72.2W Mw=4.3  EMSC   OFFSHORE COQUIMBO, CHILE     

O: 12AUG2017 12:54:11  30.3S   72.2W Mw=5.8  EMSC   OFFSHORE COQUIMBO, CHILE     

O: 12AUG2017 09:39:41  30.4S   71.6W mb=4.2  EMSC   COQUIMBO, CHILE              

P: 14AUG2017 109862    30.0S   69.0W 4.0-5.6 BAAAA  Coast Central Chile         

P: 14AUG2017 109862    30.0S   69.0W 4.0-5.6 AABAA  Coast Central Chile        

 

A moderate earthquake of M 5.3 also occurred today in Kyushu, Japan. NEIC reported it was felt with moderate intensity IV in Nichinoomote, Kagoshima, Japan. It appears to have been promoted by stresses from Typhoon Noru as noted in the previous summary:

 

 

"Typhoon Noru continued today over southwestern Honshu, Japan with winds up to 080 kts. It is expected to continue on the  track taking it over Honshu north of Tokyo. This could allow a lessening of normal friction along the subduction zone under Honshu as the island rises with lessened atmospheric pressure load. Seismicity in the region of  Honshu may include a moderate to large event as Noru passes through the region. A moderate seismic watch for the area is in effect through August 11." (August 7-8, 2017)

 

The last earthquake in Kyushu, Japan of M>=5.3 was an M 5.7 on April 29, 2017. The only other such event during 2017 has been an M 5.4 on March 11, 2017. Forecast 109445 had expected this event was likely within about 10 km of the epicenter in early August.

 

O: 12AUG2017 18:23:46  30.0N  131.2E Mw=5.3  EMSC   KYUSHU, JAPAN                

O: 12AUG2017 18:23:43  30.0N  131.1E mw=5.3  ANSS   S of Nishinoomote Japan

P:  3AUG2017 109445    30.0N  131.0E 3.5-4.9 CAAAA  Kyushu, Japan area         

 

The strongest earthquake in the U.S. or Canada today was an M 4.7 south of Alaska and east of the Alaska Peninsula. It was not reported felt in this remote area. The last earthquake within about 150 km of this epicenter with M>=4.7 was an M 4.8 seven years ago on February 12, 2010. This was an aftershock of an M 5.8 on May 16, 2009. Today's event does not appear to be an aftershock.  Forecast 109797 had expected an event in this region with moderate magnitude was likely around August 14 west of this epicenter. The distance between the M 6.6 in Sumatra and this epicenter in Alaska is 103 degrees, a distance at which seismic triggering is thought likely from energy returning to the surface after reflecting off internal earth boundaries.

 

O: 12AUG2017 14:41:21  55.5N  151.8W mb=4.7  EMSC   SOUTH OF ALASKA              

P: 14AUG2017 109797    54.7N  156.9W 3.5-5.1 AACAA  Alaska Peninsula           

 

PERU ACTIVE ALONG ENTIRE SUBDUCTION ZONE

 

EARTHQUAKE SUMMARY FOR AUGUST 11, 2017

 

The strongest earthquake in the world today was an M 5.6 (EMSC) to M 6.0 (IGP)  in Southern Peru. NEIC reported it was felt with maximum intensity V in Camana, Arequipa, Peru and in Ica, Peru. This event follows and M 6.3 in Mindoro, Philippines which occurred yesterday. Both earthquakes lie near the geomagnetic equator and are nearly antipodal to each other. Earthquake promotion from the last geomagnetic storm along with tidal and antipodal effects probably helped trigger today's series of moderate earthquakes in Peru. In addition to the M 6.0 in southern Chile, moderate quakes also occurred about every 400 km to the north including in central Chile at 13 South latitude, 8.5 South and 4.0 South latitudes in Peru. This pattern is probably not coincidental and under stronger triggering conditions could have led to a much stronger Peru-wide earthquake if these moderate  ruptures had combined into one.

 

IGP reported the earthquake in Southern Peru of M 5.6-6.0 was felt with intensity V in  Atico; IV Ocona, Caraveli; III-IV Chala, Camana, Aplao, Pausa, Viraco; II-III Arequipa, Cotahuasi, Coracora; II Nazca, Puquio, Chivay, Peru.

The last earthquake of M>=6.0 in southern Peru was an M 6.4 on July 18, 2017.  Forecast 109578 had expected this earthquake within about 50 km of the epicenter was likely around August 9. The M 6.0 is at the third node from the M 7.7 Komandorsky Islands quake of July 17 and was probably promoted from that source.

 

O: 11AUG2017 21:45:07  16.3S   73.5W Mw=5.6  EMSC   NEAR COAST OF SOUTHERN PERU  

O: 11AUG2017 21:45     18.4S   73.6W mb=6.0  IGP    Atico; IV Ocona, Caraveli; III

P:  9AUG2017 109578    18.0S   73.0W 4.0-5.8 AAAAA  So. Peru/Bolivia           

 

O: 12AUG2017 06:30     13.8S   78.5W mb=4.7  IGP    Pisco, Chincha, II Canete, Per

O: 12AUG2017 06:30:44  13.7S   76.4W mb=4.4  EMSC   NEAR COAST OF CENTRAL PERU   

P: 13AUG2017 109833    14.0S   73.0W 4.0-5.4 AACAA  Central Peru               

 

IGP reported this earthquake was felt with intensity II-III in Pisco, Chincha, II Canete, Peru. NEIC reported this earthquake of M 4.4 near the coast of central Peru  was felt with intensity II-III in the area(s) of Pisco, Ica, Peru.

 

O: 12AUG2017 02:45      8.9S   75.7W mb=5.3  IGP    Aguaytia; II-III Huanuco, Ting

O: 12AUG2017 02:45:50   8.9S   75.6W mb=4.7  EMSC   CENTRAL PERU                 

P:  3AUG2017 109566    10.0S   75.0W 3.5-5.0 CBAAA  Brazil                     

 

IGP reported this earthquake was felt with intensity III-IV in Aguaytia; II-III Huanuco, Tingo Maria; II Pucalpa, Peru. NEIC reported this earthquake of M 4.7 in Northern Peru was felt with intensity IV in the area(s) of Tingo Maria, Huanuco, Peru.

 

O: 11AUG2017 20:17      5.5S   81.2W mb=4.3  IGP    Sechura, Paita, II Talara, Piu

O: 11AUG2017 20:17:56   5.3S   80.9W mb=4.7  EMSC   NEAR COAST OF NORTHERN PERU  

P: 13AUG2017 109636     4.0S   80.0W 4.0-5.6 ABAAA  Ecuador                    

 

IGP reported this earthquake was felt with intensity III in  Sechura, Paita, II Talara, Piura, Peru. NEIC reported this earthquake of M 4.7 in Northern Peru was felt with intensity IV in the area(s) of La Huaca, Piura, Peru. 

 

 

An aftershock of M 4.8 occurred in Botswana today. NEIC reported maximum intensity IV in Molepolole, Kweneng, Botswasa and II-III in Pilane, Kgaphamadi, Tlokwent, Dumadumane, Mogoditshane, Gaborone, Gabane, Mmokolodi, Ramotswa, Sekoma, and Francistown and in South Africa at Rustenburg, and Verwoerdburg. This is an aftershock of the M 6.5 earthquake in Botswana of April 3, 2017 - an unprecedented quake - but is not at that epicenter. This epicenter lies about 150 km southeast of that  mainshock and was probably triggered by regional redistribution of local stresses. It lies near 100 degrees from the Mindoro M 6.3 event in the Philippines which occurred yesterday and at the fourth node (90 degrees) from the M 6.0 in Peru, both of which may have helped promote this event. Forecast 109592 had expected a regional moderate quake near Botswana around August 9.

 

O: 12AUG2017 02:37:47  23.6S   25.7E mb=4.8  EMSC   BOTSWANA                     

P:  9AUG2017 109592    27.0S   27.0E 3.0-4.4 BCAAA  Rep. South Africa          

 

An earthquake of M 4.2 occurred today in the region of Bridgeport and Lee Vining, California. NEIC reported it was felt with maximum intensity IV in Fish Camp, California and II-III in California at Lee Vining, Bridgeport, June Lake, Mammoth Lakes, Coleville, Yosemite National Park, Bishop, Oakhurst, Groveland, El Portal, Ml Wuk Village, Midpines, Mariposa and in general within about 100 km of the epicenter. and in Nevada at Hawthorne, Gardnerville,   The last earthquake within about 50 km of this epicenter with M>=4.2 was an M 5.8 and an aftershock of M 5.5 on December 28, 2016.  Forecast 109700 had expected a moderate quake was possible about 50 km south of this around August 14.

 

O: 12AUG2017 03:00:10  38.1N  118.9W ML=4.2  EMSC   CENTRAL CALIFORNIA           

P: 14AUG2017 109700    37.6N  118.7W 2.5-4.4 AAAAA  California/Nevada area     

 

This was followed by an M 3.7 in the Coalinga area of central California. NEIC reported this earthquake was felt with intensity II in Coalinga, California. The last earthquake to occur within about 50 km of this epicenter in the Coalinga area with M>=3.7 occurred on February 1, 2017 with M 4.2 and prior to that on March 27, 2015 with M 4.1. Forecast 109702 had expected today's event within about 25 km was likely around August 15.

 

O: 12AUG2017 08:40:00  36.3N  120.3W ML=3.7  EMSC   CENTRAL CALIFORNIA           

O: 12AUG2017 08:40:00  36.3N  120.3W ml=3.7  ANSS   NNE of Coalinga California

P: 15AUG2017 109702    36.1N  120.1W 2.5-4.4 BAAAA  Central California         

 

The strongest earthquake in the U.S. or Canada today was another in the aftershock series in the Fox Islands which followed events of M 5.4 and 5.5 in the area two days ago. These are not being felt in this remote area. Forecast 109533 had expected this activity in the Fox Islands was likely around August 9.

 

O: 11AUG2017 14:39:16  52.7N  169.3W mb=4.3  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

P:  9AUG2017 109533    51.9N  169.2W 3.5-5.2 AAAAA  Fox Islands, Aleutians     

 

TIDAL STRESSES CONTINUE TO PROMOTE SEISMICITY

 

EARTHQUAKE SUMMARY FOR AUGUST 10, 2017

 

Strong tidal stresses associated with the full moon continued to enhance seismicity on opposite sides of the globe today. The strongest earthquake of the day occurred at an intermediate focus with M 6.2 near Manila, Philippines and was widely felt but not damaging. This event occurred within about 1 hour of local solar noon, a time of high tidal stresses, and near the longitude of maximum stress as noted in previous issues. The opposite longitude in eastern Mexico was also active. Chiapas, Mexico experienced an M 5.0 and M 4.8 earthquake today, perhaps reflecting stresses from both Tropical Storm Franklin and the full moon.

 

The strong earthquake of M 6.2 at an intermediate focus beneath southern Tagalog, Philippines was felt over a large area of central Philippine but no major damage was reported. NEIC noted, among most communities within about 300 km of the epicenter,  maximum shaking IV in Southern Tagalog at Calaca, Bulihan, Silang, Santa Clara, Noveleta, Imus, Manila, Taytay, Lucban, and Guiguinto, Luzon. Intensity VI was felt in Central Luzon at Guagua and V in Gutad and San Nicolas, with IV as far as 400 km from the epicenter. 

This is the strongest earthquake in the region of Mindoro, Philippines since events of M 6.5 on October 8, 2004; an M 6.2 on October 9, 2003 and an M 7.1 on November 14, 1994. Forecast 109392 had expected this event within about 25 km of the epicenter was likely in early August. Regional activity associated with the full moon in the past several days included two strong quakes in Sichuan, China (M 6.5) and in Xinjiang, China (M 6.3).

 

O: 11AUG2017 05:28:26  14.0N  120.7E Mw=6.2  EMSC   MINDORO, PHILIPPINES         

O: 11AUG2017 05:28:25  14.0N  120.7E mw=6.2  ANSS   WSW of Tuy Philippines

P:  3AUG2017 109392    14.0N  121.0E 3.5-5.1 CAAAA  Luzon, Philippines         

 

The activity in eastern Mexico included events of M 5.0, 4.8 and 4.4. It was felt in local communities. While this region has been active throughout the year, the M 5.0 and 4.8 are the strongest events in the Chiapas region since two of M 5.6 and 5.1 accompanied the M 6.8 in Guatemala on June 14, 2007 nearly two months ago. An M 5.3 also hit the region on May 30 and again on May 31. Forecasts 109382 and 109656 had expected this activity was likely between August 7 and 15 within about 50 km of these epicenters.

 

These quakes in Chiapas, Mexico were reported felt with intensity II-III in the area(s) of Tapachula, Chiapas, Mexico and Olintepeque, Quezaltenango, Guatemala.

Like a swarm today in southern California, this event is at 103 degrees from the

M 6.7 of July 20 in the Dodecanese Islands, Greece and may have been promoted

from that source.

 

O: 11AUG2017 01:07:16  13.7N   92.9W ML=5.0  EMSC   OFF COAST OF CHIAPAS, MEXICO 

O: 10AUG2017 09:53:08  14.5N   92.8W ML=4.8  UNAM  l SUROESTE de TAPACHULA, CHIS *: 1

O: 11AUG2017 01:07:16  13.7N   92.9W ML=5.0  UNAM  al SUROESTE de CD HIDALGO, CHIS *:

P: 15AUG2017 109656    14.0N   93.0W 3.5-5.4 BAAAA  Chiapas, Mexico            

 

O: 10AUG2017 22:25:19  13.7N   93.0W ML=4.4  EMSC   OFF COAST OF CHIAPAS, MEXICO 

O: 10AUG2017 22:25:19  13.7N   93.0W ML=4.4  UNAM  al SUROESTE de CD HIDALGO, CHIS *:

P:  7AUG2017 109382    14.0N   93.0W 3.5-5.4 BAAAA  Chiapas, Mexico            

 

The activity in the Philippines and in Mexico had been anticipated in this summary as:

 

"The full moon will arrive at 18:11 UT on August 7. Longitudes which are sub-solar at the time of full moon are near 92W and 88E and include the Central U.S. Mexico and Central America in the west and India, China, Afghanistan and western Indonesia in the east. These longitude zones are most likely to see significant tidal triggering within about three days of August 7. Other areas may also see tidal triggering at this time, especially where fluids mitigate seismicity and where vertical motions are common." (August 5-7, 2017)

 

and that in Mexico as:

 

"Tropical Storm Franklin continued today north of Belize with winds up to 50 kts. It is expected to track over the Yucatan and into central Mexico over the next four days. This track allows the over-riding plate (Mexico and North America) to rise reducing normal friction across the subduction zone. This could give rise to a moderate to strong earthquake from Guerrero, Mexico east to Honduras and El Salvador including areas of Guatemala. This could combine with strong tidal stresses with the full moon today to promote a moderate to large earthquake in the next five days in the area. A seismic watch is currently in effect for eastern Mexico, Guatemala, El Salvador and Honduras through August 11." (August 8-10, 2017)

 

Many areas of the northwestern coast of the U.S. and Canada were active today. An M 5.0 in Southern Alaska was joined by an M 4.8 off the coast of Oregon and California.  The moderate earthquake in Southern Alaska today was reported by NEIC to have been felt with intensity II-III in Alaska at Anchor Point, Ninilchik, Clam Gulch, Kasilof, Soldotna, Homer, Sterling, Kenai, Cooper Landing, Anchorage, Indian, Seward, Elmendorf AFB, Fort Richardson, Willow, Girdwood, Eagle River, Wasila, and Chugiak, Alaska. This is the strongest earthquake in Southern Alaska since an M 5.5 on March 2, 2017 and the second strongest of the year. Forecast 109816 had expected this event within about 50 km of the epicenter was likely around August 17.

 

O: 11AUG2017 06:18:16  60.1N  152.5W Mw=5.0  EMSC   SOUTHERN ALASKA              

P: 17AUG2017 109816    60.2N  151.7W 3.2-5.1 CAAAA  Central Alaska              

 

The M 4.8 off the coast of Oregon is the strongest in that region in the current year. An M 4.2 on May 4 previously held that status. The last earthquake in the region with M>=4.8 within about 200 km of this epicenter was an M 5.5 on November 28, 2016 about 200 km northwest of today's epicenter.  Forecast 109783 had expected this event was likely around August 14.

 

NEIC reported this earthquake of M 4.8 off the coast of Oregon  was felt with intensity I-II in the area(s) of Smith River, Crescent City, McKinleyville, Yreka, California and in Coos Bay, Brookings and Gold Beach, Oregon.

 

O: 10AUG2017 18:59:36  42.0N  125.7W Mw=4.8  EMSC   OFF COAST OF OREGON          

P: 14AUG2017 109783    43.1N  126.5W 3.0-4.7 BBAAA  Off Coast of Oregon        

 

The strongest activity in California today was a swarm in the Holtville area near the border of Southern California and Mexico. This swarm included an M 3.2 and two events of M 2.9. Occasionally swarms in this region can increase in size and duration but that does not appear to be the current case. The last earthquake of M>=3.2 within about 50 km of this swarm occurred on July 18, 2017 (M 3.3). The last event of significantly larger magnitude in the area occurred April 29, 2017 (M 3.5-3.7). Forecast 109735 had expected this activity in this area was likely around August 12. As noted in previous reports this activity is at 103 degrees from the M 6.7 in western Turkey and was probably promoted from that source.

 

NEIC reported this earthquake of M 3.2 in California was felt with intensity II-III in the area(s) of Holtville, El Centro, Imperial, and Brawley, California.

 

O: 10AUG2017 16:36:41  32.8N  115.4W ML=2.0  EMSC   SOUTHERN CALIFORNIA          

O: 10AUG2017 23:05:15  32.8N  115.5W ML=2.1  EMSC   SOUTHERN CALIFORNIA          

O: 10AUG2017 16:45:06  32.8N  115.5W ML=2.4  EMSC   SOUTHERN CALIFORNIA          

O: 10AUG2017 17:37:02  32.8N  115.5W ML=2.4  EMSC   SOUTHERN CALIFORNIA          

O: 10AUG2017 17:40:14  32.8N  115.5W ML=2.5  EMSC   SOUTHERN CALIFORNIA          

O: 10AUG2017 17:04:09  32.8N  115.5W ML=2.9  EMSC   SOUTHERN CALIFORNIA          

O: 10AUG2017 17:14:42  32.8N  115.5W ML=3.2  EMSC   SOUTHERN CALIFORNIA          

O: 10AUG2017 22:52:09  33.2N  116.0W ML=2.9  EMSC   SOUTHERN CALIFORNIA           

P: 12AUG2017 109735    32.5N  115.7W 2.5-4.4 AAAAA  So. California             

 

MODERATE EARTHQUAKE SHAKES TOKYO, JAPAN AREA

 

EARTHQUAKE SUMMARY FOR AUGUST 9, 2017

 

A moderate earthquake of M 5.0 near Tokyo, Japan today was widely felt within

about 100 km of the epicenter. Maximum intensity IV was reported by NEIC in Chiba at Chiba, Funabashi, Ichikawa, Kashiwa, Narita, Matsudo, Tomisato, Urayasu; in Ibaraki at Mitsukaido, Toride, Naka; in Saitama at Yashio, Soka, among other communities. It was also reported felt in Tokyo, Gunma, Tochigi, Yamanashi, Shizuoka, Miyagi Prefectures, Honshu, Japan.  This was the strongest earthquake in the world since the last report.

 

This event may have been promoted by the passage of Tropical Storm Noru over Honshu north of this epicenter over the past several days. Previous issues of this summary had placed the area on a seismic watch as follows:

 

"Typhoon Noru continued today over southwestern Honshu, Japan with winds up to 080 kts. It is expected to continue on the  track taking it over Honshu north of Tokyo. This could allow a lessening of normal friction along the subduction zone under Honshu as the island rises with lessened atmospheric pressure load. Seismicity in the region of  Honshu may include a moderate to large event as Noru passes through the region. A moderate seismic watch for the area is in effect through August 11." (August 7-8, 2017)

 

The only earthquake of larger magnitude in the Tokyo area during 2017 was an M 5.5 on February 19, 2017. Forecast 109453 had expected today's event within about 30 km was likely around August 10.

 

O: 10AUG2017 00:36:30  35.7N  140.1E Mw=5.0  EMSC   NEAR EAST COAST OF HONSHU, JAP

O: 10AUG2017 00:36:30  35.7N  140.1E mw=5.0  ANSS   SE of Shiroi Japan

P: 10AUG2017 109453    36.0N  140.0E 4.0-5.4 AAAAA  Off East Coast Honshu      

 

The strongest earthquake in California today was an M 3.7 in Big Bear City, Southern California. NEIC reported it was felt with intensity II-III in Big Bear City and Big Bear Lake as well as in Angelus Oaks, Forest Falls, Skyforest, Mentone, Running Springs, Cedar Glen, Yucaipa, Lake Arrowhead, Blue Jay, Highland, Morongo Valley, Calimesa, Lucerne Valley, Apple Valley, Redlands, Beaumont, San Bernardino, Loma Linda and in general within about 100 km of the epicenter as far as Los Angeles. This event which occurred within about an hour or local solar noon may have been promoted by high tidal stresses associated with the full moon. The last earthquake within about 50 km of this epicenter with M>=3.7 was an M 3.9 on December 28, 2016  and in February, 2016 when a series of moderate quakes rocked the area. Forecast 109463 had expected this event within about 30 km was likely around August 10.

 

O:  9AUG2017 17:17:08  33.5N  116.5W ML=2.2  EMSC   SOUTHERN CALIFORNIA          

O:  9AUG2017 10:20:23  33.7N  116.7W ML=2.2  EMSC   SOUTHERN CALIFORNIA          

O:  9AUG2017 14:16:47  33.9N  116.3W ML=2.2  EMSC   SOUTHERN CALIFORNIA          

O:  9AUG2017 20:40:50  34.2N  116.9W Mw=3.5  EMSC   SOUTHERN CALIFORNIA          

O:  9AUG2017 20:40:50  34.2N  116.9W Mw=3.7  ANSS   SOUTHERN CALIFORNIA           

P: 10AUG2017 109463    33.9N  116.9W 2.5-4.5 AAAAA  So. California             

 

The strongest earthquake in the U.S. or Canada outside the Aleutians, Alaska today was an M  4.3 in the Queen Charlotte Islands of Canada. NEIC reported this earthquake of M 4.3 in Southeastern Alaska was felt with intensity II-III in the area(s) of Craig, Klawock and Ketchikan, Alaska. An earthquake of M 4.1 hit this region on March 29, 2017, but this is the strongest in the area within about 150 km of this epicenter since an M 4.8 on May 27, 2013. A strong M 7.5 hit the area on January 5, 2013 and these may be aftershocks of that event.  Forecast 109531 had expected this earthquake was likely within about 100 km  of this epicenter around August 8. A powerful nor'easter passed off the coast of Massachusetts over the past two days. The coincidence of these types of events may not be so incidental as noted in previous issues of this report.

 

O: 10AUG2017 03:44:10  54.5N  134.1W ML=4.3  EMSC   QUEEN CHARLOTTE ISLANDS REGION

O: 10AUG2017 03:44:10  54.5N  134.1W ML=4.3  NRCA  QUEEN CHARLOTTE ISLANDS REGION          

P:  8AUG2017 109531    55.0N  135.0W 3.0-4.9 AAAAA  British Colombia           

 

Aftershocks, including an M 4.8, continued today in the Fox Islands, Aleutians. The area was hit by an M 5.4 and 5.5 (updated magnitudes) early on August 9 and had been reported in the previous report:

 

"The strongest earthquakes in the U.S. or Canada were a pair of M 5.3 events in the Fox Islands. This is a remote area and these were not reported felt. Prior to these two events, the Fox Islands had seen only one earthquake  of M>5.3 during the year 2017 - an M 5.8 on May 24, 2017. Forecast 109533 had expected  today's earthquake was likely within about 50 km of this epicenter to occur around August 9." (August 9, 2017)

 

O:  9AUG2017 05:58:07  52.4N  169.0W ML=3.2  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O:  9AUG2017 13:52:39  52.5N  169.1W ML=3.8  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O:  9AUG2017 05:48:28  52.5N  169.2W Mw=5.4  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O:  9AUG2017 05:40:41  52.5N  169.2W Mw=5.5  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O:  9AUG2017 13:49:30  52.7N  169.2W mb=4.8  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

P:  9AUG2017 109533    51.9N  169.2W 3.5-5.2 AAAAA  Fox Islands, Aleutians     

 

STRONG EARTHQUAKES HIT CHINA

 

EARTHQUAKE SUMMARY FOR AUGUST 8, 2017

 

Two strong earthquakes occurred in or near China today. The first occurred in southern China with M 6.5 while the second was an M 6.3 in northcentral China near Kazakshstan. This event was reported felt with intensity III in Almaty, Kazakhstan.

 

The earthquake in Sichuan, China was reported by NEIC to have been felt with maximum intensity VI and V in Sichuan at Yaan, and IV in Yinchuan, Xichang, Xian, Shaanxi, Lanzhou, Gansu, and Mianyang, Sichuan. Intensity II-III was felt within about 1000 km of the epicenter including in Sichuan at Deyang, Guangkou, Tianpeng, Chengdu, Huayang, Baoji, Shaanxi, Leshan, Daxian, Yuxia, Chongqing, Luzhou, Fuling, Lishan, Luoyang, Henan, Jiexiu, Shanxi, Zhengzhou. Yima, Zunyi, Changsha, Hunan and Handan, Hebei, China. Most of the felt reports for this event are from cities several hundred km to the west of the epicenter. Reports from nearer the epicentral region have not yet been published, but it is likely that there was extensive damage in the epicentral area which will be published later. The last earthquake with M>=6.5 within about 250 km of this epicenter in Sichuan, China was an M 7.9 on May 12, 2008 which did extensive damage throughout the area. Forecast 109164 had expected a regional event with moderately strong magnitude in the area was possibly in late July or early August. These epicenters are located at the sixth node (60 degrees) from the Dodecanese Islands, Greece earthquake of M 6.7 which occurred on July 20 and at the seventh node (51 degrees) from the M 7.7 in the Komandorsky Islands of July 17 and may have also been promoted from that source.

 

O:  8AUG2017 22:49:31  33.2N  103.8E mb=4.5  EMSC   SICHUAN-GANSU BORDER REG, CHIN

O:  9AUG2017 02:17:04  33.2N  103.9E mb=4.8  EMSC   SICHUAN-GANSU BORDER REG, CHIN

O:  8AUG2017 13:19:50  33.2N  104.0E Mw=6.5  EMSC   GANSU, CHINA                 

P: 31JUL2017 109164    28.0N  104.0E 4.0-5.5 CCAAA  Myanmar                    

 

O:  8AUG2017 21:37:18  33.5N  103.9E mb=4.2  EMSC   SICHUAN-GANSU BORDER REG, CHIN

P:  8AUG2017 109468    35.0N   99.0E 3.5-5.1 ABCAA  So. China                  

 

NEIC reported the earthquake of M 6.3 in Northern China was felt with intensity VI in Kazakhstan at Druzhba, Almaty; IV in Toutunhe, Xinjiang, China and II-III in the area(s) of Yining, Shihezi, Urumqi, Xinjiang, China and in Esik, Almaty, Kazakhstan, Esik, Almaty, Oskemen, Astana, Kazakhstan and in Biskek, Kyrgyzstan.  Many of the cities reporting this event lie to the west in the region of Kazakhstan. Damage reports are not immediately published for this region however, but some damage from an earthquake of M>=6.3 in this area is likely and will be reported later. This may be a case of stress redistribution following the M 6.5 earlier in the day in Sichuan, China combined with high tidal stresses with the full moon. The last earthquake of M>=6.3 within about 250 km of this  epicenter was an M 6.3 on June 29, 2012. Forecasts 109545 and 109452 had expected a moderate regional earthquake in the area in early August. These epicenters are located at the third node (120 degrees) from the Guatemala earthquakes (M 6.8) of June, 2017 and may have been promoted from that source.

 

O:  9AUG2017 05:22:42  44.3N   82.9E mb=4.7  EMSC   NORTHERN XINJIANG, CHINA     

O:  8AUG2017 23:39:22  44.3N   82.7E mb=5.2  EMSC   NORTHERN XINJIANG, CHINA     

O:  8AUG2017 23:27:51  44.3N   82.9E Mw=6.3  EMSC   NORTHERN XINJIANG, CHINA     

O:  9AUG2017 00:22:36  44.4N   82.9E mb=4.5  EMSC   NORTHERN XINJIANG, CHINA     

O:  9AUG2017 00:40:27  44.5N   82.0E mb=4.4  EMSC   NORTHERN XINJIANG, CHINA     

O:  8AUG2017 23:44:37  44.5N   83.0E mb=5.3  EMSC   NORTHERN XINJIANG, CHINA     

P:  1AUG2017 109545    50.0N   88.0E 3.0-4.6 CCCAA  So. Siberia                

P: 11AUG2017 109452    39.0N   78.0E 3.8-5.4 ACCAA  Northern India             

 

The earthquakes in China appear to have been promoted by high tidal stresses as expected in previous issues of this summary:

 

"The full moon today also saw a series of moderate sub-lunar events in India and China occurring between 90 and 95 East longitude. These were accompanied by a series of moderate earthquakes in Mexico and Central America and the Central

U.S. This was expected in the tidal forecast as:" (August 8, 2017)

 

"The full moon will arrive at 18:11 UT on August 7. Longitudes which are sub-solar at the time of full moon are near 92W and 88E and include the Central U.S. Mexico and Central America in the west and India, China, Afghanistan and western Indonesia in the east. These longitude zones are most likely to see significant tidal triggering within about three days of August 7. Other areas may also see tidal triggering at this time, especially where fluids mitigate seismicity and where vertical motions are common." (August 5-7, 2017)

 

The strongest earthquakes in the U.S. or Canada were a pair of M 5.3 events in the Fox Islands. This is a remote area and these were not reported felt. Prior to these two events, the Fox Islands had seen only one earthquake  of M>5.3 during the year 2017 - an M 5.8 on May 24, 2017. Forecast 109533 had expected  today's earthquake was likely within about 50 km of this epicenter to occur around August 9.

 

O:  9AUG2017 05:40:41  52.5N  169.1W mb=5.3  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O:  9AUG2017 05:48:29  52.5N  169.2W mb=5.3  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

P:  9AUG2017 109533    51.9N  169.2W 3.5-5.2 AAAAA  Fox Islands, Aleutians     

 

An unusual earthquake near Temiscaming, Ontario, Canada occurred on August 7 with M 2.0. While not felt or damaging this event emphasizes the antipodal nature of some seismicity. In the previous summary it had been noted in regard to an M 5.8 in the South Indian Ocean:

 

"The antipode of this event (in the South Indian Ocean) at 47N 80W is located at a slightly active area  of Ontario north of Ohio and may see a triggered small event in the next several days." (August 7, 2017)

 

O:  7AUG2017 20:56:44  47.1N   78.5W ML=2.0  NRCA  65 km NE from Temiscaming     

P:  7AUG2017 109503    47.0N   76.0W 2.0-4.1 AABAA  New York State             

 

O:  6AUG2017 19:32:06  47.3S   99.8E Mw=5.8  EMSC   SOUTHEAST INDIAN RIDGE       

O: 06AUG2017 19:32:06  47.3S   99.8E mw=5.8  ANSS   Southeast Indian Ridge"

P:  4AUG2017 109611    46.0S   96.0E 4.0-5.4 ABCAA  So. Indian Ocean           

 

The strongest earthquake in California today was an M 2.8 in the region south of San Francisco. An M 2.0 also occurred within San Francisco. The M 2.8 was widely felt with light intensity. NEIC reported this earthquake of M 2.8 in Central California was felt with intensity II-III in the area(s) of California at Gilroy, San Martin, Morgan Hill and San Jose, California. The last earthquake within about 30 km of this epicenter with M>=2.8 occurred on July 21, 2017 (M 2.8). The last of larger magnitude was an M 3.1 on July 17, 2017. Forecast 109434 had expected this event within this area was likely around August 8.

 

O:  8AUG2017 17:29:14  37.0N  121.5W MD=2.8  EMSC   NORTHERN CALIFORNIA          

P:  8AUG2017 109434    36.8N  121.3W 2.5-4.8 AAAAA  Central California         

 

MODERATE AFTERSHOCK SHAKES DEDECANESE ISLANDS, TURKEY

 

EARTHQUAKE SUMMARY FOR AUGUST 7, 2017

 

A moderate aftershock of M 5.3 struck the Dodecanese Islands and western Turkey today. This event, which occurred in conjunction with the full moon, appears to confirm the role of tidal stress in this sequence. Today's  event is the strongest aftershock to date of the M 6.7 mainshock of July 20, 2017 as noted in this summary at the time:

 

"A strong earthquake of M 6.7 hit the Greek Dodecanese Islands today. This was a tidally promoted event as it occurred within about 15 minutes of local solar midnight in an area where high tidal stresses and triggering were expected at this time as noted in the previous issue of this report: (July 21, 2017)

 

 

"The new moon will arrive on July 23 at 09:46 UT. Longitudes which are sub-solar at this time center around 35 East longitude while those which are anti-solar are near 145 West longitude. These include the East African Rift, the middle east and eastern Europe in the east and Alaska in the west. Tidal triggering will enhance seismicity in these area but tidal triggering is not limited to these longitude and could occur in many tectonic regimes. Tidal enhancement of seismicity is most likely through July 26 and may combine with stresses from tropical storms and geomagnetic storms to trigger strong earthquakes." (July 19-20, 2017)

 

The region of western Turkey and the Dodecanese Islands was active over the past two days, especially around local midnignt and local solar noon, a pattern which is likely to reflect tidal stress which is strongest at these hours.

 

The M 5.3 today was reported by NEIC to have been felt with intensity IV in the

Dodecanese Islands at Kos, Ziparioni, Kardamaina, and Milas, Mugla, Turkey. Intensity II-III was felt in Turkey at Marmaris, Izmir, Datca and Istanbul and in Greece at Kokkarion, Fanai, Kefalos, and Pilion. A foreshock of M 4.6 hit earlier in the day and was felt with intensity IV in Kos, Dodecanese Islands and III in Datca and Bodrum, Turkey.

 

Forecast 109427 and 109426 had expected this aftershock was likely with the

full moon in early August, 2017. Guatemala, El Salvador, Southern California, the Mariana Islands and Costa Rica, where moderate earthquakes occurred today are at 103 degrees from the Dodecanese epicenters, a distance at which earthquake triggering is deemed likely and were probably promoted by energy from this source.

 

O:  7AUG2017 05:44:25  37.0N   27.6E ML=4.0  EMSC   DODECANESE IS.-TURKEY BORDER R

O:  8AUG2017 01:46:19  37.0N   27.6E ML=4.2  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 08AUG2017 07:42:22  37.0N   27.6E mw=5.3  ANSS   SE of Bodrum Turkey

O:  8AUG2017 07:42:20  37.0N   27.6E Mw=5.3  EMSC   WESTERN TURKEY               

P: 10AUG2017 109427    38.0N   26.0E 3.0-4.8 AAAAA  Aegean Sea                 

 

O:  7AUG2017 05:18:47  37.0N   27.6E mb=4.6  EMSC   WESTERN TURKEY               

P:  2AUG2017 109426    37.0N   27.0E 3.0-4.6 BAAAA  Aegean Sea                 

 

The strongest seismicity of the day, however, occurred in the New Britain (M 5.8) and Bismarck Sea areas (M 5.3, 5.3, 5.2) of the southwest Pacific.  This continues activation of the region which began earlier in August. The event in New Britain of M 5.8 was lightly felt and is the strongest  in that region since an M 6.2 on May 15. The Bismarck Sea events were the strongest in that region during the year 2017. The last of larger magnitude than M 5.3 occurred on January 31, 2016 with M 5.6. Forecast 109366 had expected the New Britain earthquake around August 11 while forecast 109367 had anticipated the Bismarck Sea earthquakes were likely within about 100 km around August 5. The event in the New Britain region is at the third node (120 degrees) from the Dodecanese Islands while the Bismarck Sea activity is at the third node from the events of Guatemala of June, 2017 (M 6.8, 6.8). The activity in the Bismarck Sea is also at the sixth node (60 degrees) from the Komandorsky Islands M 7.7 of July 17.

 

O:  7AUG2017 06:26:43   5.4S  151.8E Mw=5.8  EMSC   NEW BRITAIN REGION, P.N.G.   

P:  7AUG2017 109571    10.0S  151.0E 4.0-5.6 ACAAA  New Ireland                

P: 11AUG2017 109366     4.0S  153.0E 4.0-5.5 BBAAA  New Britain                

 

O:  7AUG2017 12:12:11   3.4S  146.8E mb=5.3  EMSC   BISMARCK SEA                  

O:  7AUG2017 12:02:50   3.4S  146.9E Mw=5.3  EMSC   BISMARCK SEA                 

O:  7AUG2017 11:07:25   3.4S  146.9E mb=5.2  EMSC   BISMARCK SEA                 

P:  5AUG2017 109367     4.0S  146.0E 4.0-5.6 AAAAA  New Ireland                

 

An earthquake of M 4.9 in the Ryukyu Islands, Japan today was widely felt with maximum intensity III in Okinawa at Chatan, Tomigusuku, Okinawa and II in Naha, Ginowan and Ishikawa, Japan.

 This event may have been promoted by stresses from Typhoon Noru as noted in previous summaries:

 

"Typhoon Noru continued today over Kyushu, Japan with winds up to 100 kts. It is expected to continue on the unusual track to the south of Honshu. Seismicity in the region of Kyushu, the Ryukyu Islands and Honshu may include a moderate to large event as Noru passes through the region." (August 5-6, 2017)

 

Today's event in the Ryukyu Islands follows an M 5.2 on July 19 near this epicenter and an M 5.9 north of this on July 26 in the Ryukyu Islands. Forecast 109421 had expected today's epicenter would be active around August 4.

 

O:  8AUG2017 05:49:38  26.8N  127.2E mb=4.9  EMSC   RYUKYU ISLANDS, JAPAN        

P:  4AUG2017 109421    26.0N  126.0E 4.0-5.6 BAAAA  Ryukyu Islands             

 

The strongest earthquakes in California today were a pair of M 3.0 events  on the southern border with Baja California, Mexico. These were followed by a series of light aftershocks. These epicenters are at 103 degrees from the Dodecanese Islands and were probably promoted by energy from that region, which continued active today. As the events of M 3.0 occurred within about an hour of local solar midnight, they were also probably promoted by tidal stresses with the full moon today. The last similar activity within about 30 km of this epicenter occurred on January 1, 2017 with events of M 3.1 which followed a strong swarm and an M 4.0 on December 31, 2016. Forecast 109459 had expected today's activity was likely around August 6.

 

NEIC reported these two earthquakes of M 3.0 in Baja California were felt with intensity II-III in the area(s) of El Centro, Holtville, Mexicali, Baja, Imperial, Fontana, Rancho Cucamonga, Chino, California.

 

O:  7AUG2017 13:57:30  32.0N  116.2W ML=2.2  EMSC   BAJA CALIFORNIA, MEXICO      

O:  7AUG2017 09:00:05  32.8N  115.5W ML=2.1  EMSC   SOUTHERN CALIFORNIA          

O:  7AUG2017 12:45:42  32.8N  115.5W ML=2.2  EMSC   SOUTHERN CALIFORNIA          

O:  7AUG2017 14:22:01  32.8N  115.5W ML=2.2  EMSC   SOUTHERN CALIFORNIA          

O:  7AUG2017 11:52:25  32.8N  115.5W ML=2.3  EMSC   SOUTHERN CALIFORNIA          

O:  7AUG2017 12:27:59  32.8N  115.5W ML=2.6  EMSC   SOUTHERN CALIFORNIA          

O:  7AUG2017 08:34:01  32.8N  115.5W ML=3.0  EMSC   SOUTHERN CALIFORNIA          

O:  7AUG2017 08:44:05  32.8N  115.5W ML=3.0  EMSC   SOUTHERN CALIFORNIA          

P:  6AUG2017 109459    32.4N  115.8W 2.5-4.5 AAAAA  So. California             

 

The full moon today also saw a series of moderate sub-lunar events in India and China occurring between 90 and 95 East longitude. These were accompanied by a series of moderate earthquakes in Mexico and Central America and the Central

U.S. This was expected in the tidal forecast as:

 

"The full moon will arrive at 18:11 UT on August 7. Longitudes which are sub-solar at the time of full moon are near 92W and 88E and include the Central U.S. Mexico and Central America in the west and India, China, Afghanistan and western Indonesia in the east. These longitude zones are most likely to see significant tidal triggering within about three days of August 7. Other areas may also see tidal triggering at this time, especially where fluids mitigate seismicity and where vertical motions are common." (August 5-7, 2017)

 

O:  8AUG2017 00:35:37  24.4N   93.5E ML=4.3  EMSC   MANIPUR, INDIA REGION        

P:  9AUG2017 109416    24.0N   94.0E 4.0-5.6 AAAAA  Myanmar                    

 

O:  7AUG2017 11:25:07  26.3N   91.7E ML=3.4  EMSC   ASSAM, INDIA                 

P:  9AUG2017 109416    24.0N   94.0E 4.0-5.6 ACBAA  Myanmar                    

 

O:  7AUG2017 13:12:36  31.8N   94.7E mb=4.5  EMSC   EASTERN XIZANG               

P:  6AUG2017 109468    32.0N   95.0E 3.5-5.1 AAAAA  So. China                  

 

O:  7AUG2017 10:47:30   9.6N   85.9W mb=4.7  EMSC   OFF COAST OF COSTA RICA      

P:  6AUG2017 109381    10.0N   84.0W 3.5-5.1 AABAA  Caribbean Sea              

 

O:  7AUG2017 06:15:05  13.0N   90.0W Mw=4.7  EMSC   OFFSHORE EL SALVADOR         

P:  1AUG2017 109387    14.0N   90.0W 3.5-5.5 CAAAA  Guatemala                  

 

O:  7AUG2017 04:58:47  17.4N   94.9W ML=4.3  UNAM  l SUR de SAYULA DE ALEMAN, VER

P:  6AUG2017 109383    17.0N   94.0W 3.5-5.1 AAAAA  Chiapas, Mexico            

 

EARTHQUAKE IN SOUTH INDIAN OCEAN TIDALLY PROMOTED

 

EARTHQUAKE SUMMARY FOR AUGUST 6, 2017

 

The strongest earthquake of the day was an M 5.8 in the South Indian Ocean. This is a remote oceanic area and this event was not reported felt. At 99 East longitude and occurring within several hours of local solar midnight this  is a prime candidate for tidal promotion with the full moon. The forecast for tidal seismicity at this time had read:

 

"The full moon will arrive at 18:11 UT on August 7. Longitudes which are sub-solar at the time of full moon are near 92W and 88E and include the Central U.S.

Mexico and Central America in the west and India, China, Afghanistan and western Indonesia in the east. These longitude zones are most likely to see significant tidal triggering within about three days of August 7. Other areas may also see tidal triggering at this time, especially where fluids mitigate seismicity and where vertical motions are common." (August 5-7, 2017)

 

The antipode of this event at 47N 80W is located at a slightly active area of Ontario north of Ohio and may see a triggered small event in the next several days. This is the strongest earthquake within about 250 km of this epicenter since an M 6.2 on February 5, 2010 and before that on April 9, 2006 (M 5.8).  The strongest quake in the area in the past 25 years was an M 6.5-6.6 on June 13, 2002. Forecast 109611 had expected this event in the South Indian Ocean was likely around August 4.

 

O:  6AUG2017 19:32:06  47.3S   99.8E Mw=5.8  EMSC   SOUTHEAST INDIAN RIDGE       

O: 06AUG2017 19:32:06  47.3S   99.8E mw=5.8  ANSS   Southeast Indian Ridge"

P:  4AUG2017 109611    46.0S   96.0E 4.0-5.4 ABCAA  So. Indian Ocean           

 

A second event in the Southwest Indian Ridge occurred about half an hour before the event in the southeast Indian Ridge. This event of M 4.7 also appears to have been tidally promoted as it occurred within about 15 minutes of local solar midnight in a zone of high tidal stress. This event is the strongest within about 200 km of this epicenter since an M 4.8 and 5.5 on July 12, 2016. Forecast 109607 had expected it was likely around August 5. This, and the earthquake in the Southeast Indian Ridge of M 5.8 are both located at 145 degrees from the events in Guatemala of June (M 6.8). This is a distance at which seismic energy is concentrated at the surface following large earthquakes and it is likely these were promoted by energy from Guatemala.

 

O:  6AUG2017 20:09:01  33.2S   57.1E mb=4.7  EMSC   SOUTHWEST INDIAN RIDGE       

P:  5AUG2017 109607    34.0S   55.0E 4.0-5.6 AABAA  So. Indian Ocean           

 

Seismicity in Mexico and Central America was also high today and included a half dozen events of M>=4. The strongest of these appears to have been tidally promoted at it occurred within 15 minutes of local solar midnight at 90 West longitude. This event of M 4.7 occurred off the coast of El  Salvador. It appears to be an aftershock of an M 6.2 at this epicenter which occurred May 12, 2017, the second strongest long-term aftershock in the area since an M 5.3 on May 25, 2017. Forecast 109387 had expected this event in early August.

 

O:  7AUG2017 06:15:03  13.0N   90.0W Mw=4.7  EMSC   OFFSHORE EL SALVADOR         

P:  1AUG2017 109387    14.0N   90.0W 3.5-5.5 CAAAA  Guatemala                  

 

The most unusual earthquake and largest in the general areas of the U.S., Canada and surroundings was an M 4.1 in Sonora, Mexico. This event is the largest within about 150 km of this epicenter since an M 4.5 within about 25 km of this epicenter on October 16, 1999. Today's event was not reported felt.

 

O:  6AUG2017 22:55:00  30.8N  110.9W ML=4.1  EMSC   SONORA, MEXICO               

O: 06AUG2017 22:55:00  30.7N  110.8W ML=4.1  UNAM  l NORESTE de MAGDALENA DE KINO, SO

 

 

UNUSUAL ACTIVITY IN SOUTHWEST PACIFIC

 

EARTHQUAKE SUMMARY FOR AUGUST 5, 2017

 

A series of unusual earthquakes in the region of Zealandia and Australia occurred today. In addition to the strongest earthquake of the year in Australia (M 4.8) and an unusual M 4.6 in the Auckland Islands of New Zealand, the strongest earthquake in the world today was an M 5.7-5.8 near-local noon event in the Solomon Islands. The timing suggests tidal or geomagnetic promotion.

NEIC reported it was felt with intensity IV in Honiara, Guadalcanal, Solomon Islands. The last earthquake within about 200 km of this epicenter with M>=5.8 was recorded on January 10 and 19, 2017 with M 6.3 and 6.5 respectively. An aftershock of these events most recently occurred as an M 5.8 on May 24, 2017. 

Forecast 109583 had expected today's event within about 100 km of this epicenter in early August.

 

O:  6AUG2017 00:15:10  10.2S  161.4E Mw=5.8  EMSC   SOLOMON ISLANDS              

O: 06AUG2017 00:15:10  10.3S  161.5E mw=5.7  ANSS   Kirakira Solomon Islands

P:  1AUG2017 109583    11.0S  162.0E 4.0-5.6 BAAAA  Vanuatu Islands            

 

An unusual earthquake occurred today with M 4.6 south of the Auckland Islands, New Zealand. This is a remote area and the event was not reported felt. It  follows events of M 6.5 and 4.9 on July 11 and 12 and foreshocks on May 22 and 24 of M 4.8 and 4.9. These events occurred about 400 km northeast of today's epicenter and this event is not a classical aftershock of those. It is the strongest earthquake within about 200 km of this epicenter since an M 4.6 on July 24, 2013. The last event of significantly larger magnitude in the area was an M 6.0 on November 5, 2009. Forecast 109614 had expected a moderate aftershock in the area in early August. This epicenter is located at 104-105 degrees from the M 7.7 Komandorsky Island earthquake of July 17 and at 145 degrees from the Dodecanese quake of July 20 and was probably promoted by concentrated seismic reflections and refractions which return to the surface at this distane.

 

O:  5AUG2017 22:42:40  51.3S  162.3E mb=4.6  EMSC   AUCKLAND ISLANDS, N.Z. REGION

O: 05AUG2017 22:42:40  51.3S  162.3E mb=4.6  ANSS   Auckland Island New Zealand

P:  2AUG2017 109614    48.0S  165.0E 3.0-5.1 BCBAA  Southern S. Isl. N.Z.      

 

A second unusual earthquake in Australia occurred near Halls Creek in north-central Australia. It was reported felt with intensity III in the epicentral area. It is the strongest earthquake of hit Australia during the year 2017. The last earthquake within about 300 km of this epicenter in Western Australia of M>=4.9 occurred more than 25 years ago. The only events within this distance of today's epicenter of M>=4 in the past 25 years occurred on November 6, 2016 (M 4.8); December 5, 2003 (M 4.8) and December 16, 1995 (M 4.2). Today's event had not been forecast. Today's epicenter is at 152-143 degrees from the events in Guatemala of mid-June, a distance at which seismic promotion is likely.

 

O:  6AUG2017 04:21:49  19.2S  128.0E mb=4.9  EMSC   WESTERN AUSTRALIA             

O: 06AUG2017 04:21:51  19.2S  128.1E mb=4.9  ANSS   Halls Creek Australia

 

The largest earthquake in the U.S. or Canada today was an M 4.6 in the Rat Islands, Aleutians. This event was not felt in this remote area. The last earthquake of M>=4.6 in the Rat Islands occurred on June 21, 2017 with M 5.0. The strongest event in the area during the current year was an M 5.8 on April 27, 2017. Forecast 109543 expected today's earthquake within about 50 km of the epicenter was most likely around August 2. This epicenter is about 200 km from the antipode of the moderate earthquakes in the Southern Atlantic of the past three days. It is about 400 km east of the M 7.7 Komandorsky Islands earthquake of July 17 and was probably a regional reaction to that event.

 

O:  5AUG2017 10:05:37  51.4N  178.8E mb=4.6  EMSC   RAT ISLANDS, ALEUTIAN ISLANDS

P:  2AUG2017 109543    52.0N  179.0E 4.0-5.7 BAAAA  Rat Islands                

 

The most unusual earthquake in the U.S. today was an M 1.8 in southern Pennsylvania. Earthquakes in this area often precede by hours to several days events in  Southern or Central California of moderate magnitude. Today's event of M 1.8 however, is probably not a precursor as it is too small. The larger the event in Pennsylvania the stronger the expected California event in general. The last earthquake recorded in Southern Pennsylvania of any magnitude by ANSS was an M 2.3 on April 23, 2017 and prior to that an M 3.0 on January 17, 2016. Forecast 109444 expected a regional event was possibly around August 7.  Today's event occurred within about 30 minutes of local solar midnight and may have been promoted by tidal stresses which maximize near this hour.

 

O:  5AUG2017 05:26:56  39.8N   76.4W ml=1.8  ANSS   Susquehanna Trails Pennsylvani

P:  7AUG2017 109444    37.0N   77.0W 2.0-4.1 ACAAA  Kentucky/Tennessee/NC      

 

SEISMICITY IN MINDANAO, PHILIPPINES COINCIDES WITH NEW GEOMAGNETIC STORM

 

EARTHQUAKE SUMMARY FOR AUGUST 4, 2017

 

The strongest earthquake in the world today was an M 5.8 in Southern Mindanao, Philippines. NEIC reported it was felt with maximum intensity V in Buayan, southern Mindanao and IV in Mindanao at Katangawan, Klinan, Polo, Pongpong, San Jose, and Sulit and II-III in Polonuling, Bato, Davao, Biao, Taywanak, Malanday, Southern Tagalog, Philippines.  A regional aftershock of M 5.0 also occurred about 300 km north of the M 5.8 in northern Mindanao. NEIC reported maximum intensity VI in Valencia, Northern Mindanao; V in Lais, Southern Mindanao; IV in Cagayan, Barra, Gingoog; and II-III in Butuan, Caraga, Libertad, Opol, Lumbia, Damilag, Manolo Fortich, Northern Mindanao, Philippines. These events lie on the geomagnetic equator and coincided with the strongest  geomagnetic storm in nearly three weeks. They were probably promoted by the initial effects of this storm.

 

The geomagnetic field was at minor storm conditions today.  The AP level was 23.

High latitude geomagnetic field saw major storm conditions with AP at 39. This is the strongest geomagnetic storm since AP reached 41 on July 16-17. The earthquakes near the geomagnetic equator in Mindanao, Philippines may have been promoted by effects from these storms. Further activity along the geomagnetic equator and/or at high latitudes is likely over the next three days and is most likely towards the period August 7-9. The current storm conditions are likely to be short-lived.

 

The last earthquakes of M>=5.8 in Mindanao occurred as an M 6.8 on April 28  near the southern epicenter today and as an M 5.7 on April 11, 2017 near the northern epicenter. Forecasts 109099 and 109347 had expected this activity within about 150 and 25 km of the epicenters likely in late July or early August. This activity is at the sixth node (60 degrees) from the M 7.7 in the Komandorsky Islands of July 17 and may have been promoted from that source.

 

O:  5AUG2017 00:30:42   6.2N  125.4E Mw=5.8  EMSC   MINDANAO, PHILIPPINES        

P: 26JUL2017 109099     6.0N  127.0E 4.0-5.7 CABAA  Halmahera                  

 

O:  5AUG2017 07:39:17   8.0N  125.3E mb=5.0  EMSC   MINDANAO, PHILIPPINES        

P:  3AUG2017 109347     8.0N  125.0E 4.0-5.6 AAAAA  Central Philippines        

 

An M 5.1-5.8 also was recorded east of Taiwan today.  CWB reported this earthquake was felt with intensity II in Yilan Taitung and Changhua Counties and I in Hualien, Nantou, Hsinchu, Chiayi, Taichung, Yunlin, Changhua, Taipei Counties, Taiwan. This event may have been promoted by Tropical Storm Haitung as previous noted in this report:

 

"TS HAITANG (TD 12W) continued today west of the Philippines and Taiwan with winds up to 40 kts. It is expected to track to the north and to dissipate over southern China around August 1. Some increases in seismicity in Taiwan and the northern Philippines are possible with this storm in the region. The antipode is at 26S 61W in an active seismic area of Bolivia. A moderate, promoted, earthquake in this area is possible in the next three days. " (August 1, 2017)

 

The last earthquake within about 300 km of this epicenter east of Taiwan with M>=5.8 was an M 6.1 on May 9, 2017. An aftershock of M 5.1 occurred June 2. This is the largest earthquake within about 200 km of this epicenter during the current year, however. The last event in this region of M>=5.8 was an M 5.9 on June 23, 2016. The last of M>=5.1 was an M 5.4 on November 24, 2016. Forecasts 109424 and 109421 had expected this activity was likely in early August.

 

O:  4AUG2017 11:19:46  24.6N  123.6E Mw=5.1  EMSC   SOUTHWESTERN RYUKYU ISL., JAPA

O:  4AUG2017 11:19:41  24.2N  124.0E ML=5.8  TAI    Hualien, Taiwan              

P:  1AUG2017 109424    24.0N  123.0E 4.0-5.4 BAAAA  Taiwan                     

P:  8AUG2017 109421    25.0N  123.0E 4.0-5.5 BAAAA  Ryukyu Islands             

 

Typhoon Noru was also helping seismicity along today. Moderate earthquakes in the Volcano and Izu Islands of southeastern Japan were probably promoted by stresses from Noru as expected in previous reports:

 

"Super Typhoon Noru continued today in the Volcano Islands region with winds up to 130 kts. It is expected to continue on the unusual track to the south along the  Volcano-Mariana arc over the next several days. Unusual stresses are placed on the earth when tropical storms run counter to the normal track direction and and help promote strong earthquakes in their unusual wake. Normally storms in this region track to the northeast, so Noru is a strong exception to the normal tracking and could trigger  a moderate to large regional event." (August 1-2, 2017)

 

O:  5AUG2017 00:39:46  25.7N  139.3E mb=5.0  EMSC   VOLCANO ISLANDS, JAPAN REGION

P:  3AUG2017 109409    29.0N  140.0E 4.0-5.6 ACAAA  Bonin Islands              

 

O:  4AUG2017 09:49:06  32.4N  142.0E mb=4.7  EMSC   IZU ISLANDS, JAPAN REGION    

P:  5AUG2017 109471    34.0N  143.0E 4.0-5.4 ABAAA  So. of Honshu              

 

In the west a storm north of Venezuela was likely a promoter of a minor earthquake in Venezuela today. In the previous issue this reported noted this possibility as:

 

"Tropical cyclones may be forming near Trinidad and Tobago and in the eastern Central Atlantic at 7N 25W. NHC gives these 20% and 40% chance of becoming tropical cyclones in the next two days. The storm north of Venezuela may  increase seismicity in the eastern Caribbean in the next several days." (August 4, 2017)

 

O:  4AUG2017 18:44:59   8.9N   71.4W Mw=3.4  EMSC   ZULIA, VENEZUELA             

P:  2AUG2017 109400    10.0N   70.0W 3.4-5.1 ABBAA  No. Venezuela              

 

The strongest earthquake in the U.S. or Canada today was an M 4.8 in the Andreanof Islands, Alaska. It was not reported felt in this remote epicentral zone. This is probably an aftershock of the M 6.4 which hit this epicenter on May 8, 2017, the second largest long-term aftershock of that event. The other occurred as an M 4.9 on June 21, 2017. Forecast 109528 had expected this event within about 50 km was likely around August 7.

 

O:  5AUG2017 02:07:46  51.5N  178.5W mb=4.8  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P:  7AUG2017 109528    51.6N  177.6W 3.5-5.3 AAAAA  Andreanoff Isls, Aleutians 

 

UPCOMING SOLAR ECLIPSE MAY AFFECT U.S. SEISMICITY

 

EARTHQUAKE SUMMARY FOR AUGUST 3, 2017

 

A light M 2.7 earthquake was widely felt in eastern Tennessee today. NEIC reported it was felt with intensity II-III in Kodak, Sevierville, Dandridge, New Market, Seymour, Jefferson City, Knoxville, Gatlinburg, La Follette, Jonesboro, Columbia, Tennessee and possibly as far as Virginia and Indiana. The maximum solar eclipse of August 21 will occur near this epicenter. More regional seismicity, including a possible moderate earthquake, is likely leading up to and following the eclipse. The tidal forecast for the full moon of August 7 and the new moon of August 21 reads:

 

"The full moon will arrive at 18:11 UT on August 7. Longitudes which are sub-solar at the time of full moon are near 92W and 88E and include the Central U.S. Mexico and Central America in the west and India, China, Afghanistan and western Indonesia in the east. These longitude zones are most likely to see significant  tidal triggering within about three days of August 7. Other areas may also see tidal triggering at this time, especially where fluids mitigate seismicity and where vertical motions are common. The much-anticipated solar eclipse of August 21 will pass over much of the central U.S. and will be viewed by millions of people at this vacation time of year. The full eclipse will be visible from the Pacific Northwest through Lincoln, Nebraska and into the southeast of the U.S. Tidal triggering could occur in Washington, Oregon or Northern California with lesser triggering in the central and southeastern U.S. Like the full moon this will reach maximum when over 97 West longitude (83 East) with maximum effects in the regions of Oklahoma and Kansas. The greatest  eclipse will occur over the New Madrid Fault in Missouri and Tennessee. A  moderate earthquake is possible in this area in the period August 18-25." (August 3-4, 2017)

 

The strongest earthquakes in Eastern Tennessee during 2017 have been of M 2.7-2.8 and occurred with the last new moons on July 23 and June 25. These events suggest a component of tidal triggering and a larger than average likelihood of a moderate regional event with the new moon of August 21. Forecast 109444  had expected today's event was likely around August 2.

 

 

O:  4AUG2017 00:40:14  35.9N   83.6W MD=2.7  EMSC   EASTERN TENNESSEE            

P:  2AUG2017 109444    36.0N   83.0W 2.0-4.2 AAAAA  Kentucky/Tennessee/NC      

 

 

The strongest earthquake in the U.S. or Canada today was an M 3.6 in Northern

California. NEIC reported it was felt with intensity II in Janesville, Susanville and Carmichael, California. The last earthquake with M>=3.6 within about 100 km of this epicenter occurred exactly one year ago on August 2 and August 4, 2016 as a series of events of M 4.1, 4.8, and 4.4. Yearly repeats of earthquakes are not uncommon and are statistically significant. Weather patterns are the most likely promoting factor of annual earthquakes. Forecast 109506 expected today's event in this region was likely around August 5.

 

O:  3AUG2017 21:25:01  40.4N  120.0W Mw=3.6  EMSC   NORTHERN CALIFORNIA          

P:  5AUG2017 109506    40.0N  120.9W 2.5-4.4 AAAAA  Northern California        

 

The most widely felt earthquake in the world today was an M 5.1 south of Java, Indonesia. NEIC reported it was felt with intensity IV in Yogyakarta at Depok and in Java at Sidareja and II-III at Jatiwangi and Wonosobo, Java and in Yogyakarta at Kasihan and Yogyakarta, Indonesia. BMG reported it was felt with intensity III in Cilacap, Bantul, Purworejo, Pandandaran, Kebumen; II-III in Kulon Progo, Yogyakarta and Godean and II in Pacitan, Java, Indonesia. This was a near local solar midnight earthquake and was possibly promoted by tidal stresses which normally maximize at this hour. The last earthquake of M>=5.1 in the region South of Java occurred July 8, 2017 with M 5.2. The strongest of the year was an M 5.6 on April 29 and again on June 11, 2017. Forecast 109372  had expected today's event was likely within about 100 km of the epicenter around August 4.

 

O:  3AUG2017 16:14:25   8.3S  109.0E mb=5.1  EMSC   JAVA, INDONESIA              

O: 03AUG2017 16:14:23  08.4S  109.0E MS=5.3  BMG  Felt with intensity III

P:  4AUG2017 109372     8.0S  108.0E 4.0-5.5 AAAAA  So. of Java                

 

The strongest global activity today was a pair of M 5.3 quakes in the region of Tonga. These were accompanied by other shocks of M 4.9. These are not unusual events. The strongest earthquake in Tonga during 2017 has been an M 5.6 on July 16 and an M 5.5 on July 16 at the epicenter near 20 South latitude but a M 5.3 also occurred at the 17 South latitude on July 17 after three months of inactivity in the region at these magnitude levels. Forecasts 109313 and 109581 had expected this activity in late July or early August.

 

O:  3AUG2017 09:52:23  17.6S  172.9W mb=4.9  EMSC   TONGA REGION                 

O:  3AUG2017 08:53:31  17.7S  172.9W Mw=5.3  EMSC   TONGA REGION                 

P: 30JUL2017 109313    17.0S  173.0W 4.0-5.6 BAAAA  Tonga Islands              

 

O:  3AUG2017 23:43:26  19.8S  173.6W mb=5.3  EMSC   TONGA                        

P:  3AUG2017 109581    19.0S  174.0W 4.0-5.6 AAAAA  Tonga Islands              

 

Light earthquakes also continued today in Oklahoma following the M 4.2 there yesterday. An M 3.3 was felt with intensity IV in Oklahoma at Edmond and II-III in Arcadia, Oklahoma City, Guthrie, Cashion, Cushing, Enid, and Claremore. Reports from Wichita, Kansas; Aubrey, Texas; Ozark, Arkansas and Blair, Nebraska are probably in error. An M 3.2 was reported felt in Cushing, Stroud, Edmond and Tulsa, Oklahoma. An M 2.9 near Guthrie was felt there with intensity II-III and in Edmond, Coyle, Arcadia, and Oklahoma City, Oklahoma. NEIC reported the earthquake of M 2.6 in Oklahoma was felt with intensity IV in Luther, Oklahoma and II-III in the area(s) of Oklahoma City, Oklahoma.

 

Light earthquakes near the upcoming eclipse path also occurred today as a minor swarm in Arkansas, Kansas and in Virginia. These areas could see activation with high tidal stresses. Much of this activity, as well as that in Tonga, is occurring at the fifth node from the M 7.7 in the Komandorsky Islands of July 17 and may be promoted from that source.

 

O:  3AUG2017 22:01:04  35.7N   97.2W mb=2.6  EMSC   OKLAHOMA                     

O:  3AUG2017 16:11:46  35.7N   97.4W mb=3.3  EMSC   OKLAHOMA CITY AREA, OKLAHOMA 

O:  3AUG2017 06:40:44  35.7N   97.4W mb=3.5  EMSC   OKLAHOMA CITY AREA, OKLAHOMA 

O:  3AUG2017 11:05:41  35.8N   97.4W mb=2.9  EMSC   OKLAHOMA                     

O:  4AUG2017 06:58:49  35.9N   96.7W mb=2.3  EMSC   OKLAHOMA                     

O:  3AUG2017 14:50:10  35.9N   96.7W mb=3.2  EMSC   OKLAHOMA                     

P:  3AUG2017 109474    36.0N   97.0W 2.0-4.1 AAAAA  Southern Plains            

 

O:  3AUG2017 10:06:33  36.4N   93.0W MD=2.1  EMSC   ARKANSAS                     

O: 03AUG2017 10:32:42  36.4N   93.0W md=1.8  ANSS   NE of Harrison Arkansas

O: 03AUG2017 10:31:14  36.3N   93.0W md=1.0  ANSS   NE of Harrison Arkansas

O: 03AUG2017 10:29:57  36.4N   93.0W md=1.2  ANSS   NE of Harrison Arkansas

O: 03AUG2017 10:27:36  36.4N   93.0W md=1.7  ANSS   NNE of Harrison Arkansas

O: 03AUG2017 10:06:33  36.4N   93.0W md=2.1  ANSS   NE of Harrison Arkansas

P:  8AUG2017 109448    38.0N   91.0W 2.0-4.6 BBBAA  New Madrid area            

 

O:  3AUG2017 15:18:03  37.1N   97.6W mb=2.3  EMSC   KANSAS                       

P:  3AUG2017 109474    36.0N   97.0W 2.0-4.1 AAAAA  Southern Plains            

P: 31JUL2017 109215    37.0N   97.0W 2.0-4.0 BAAAA  Southern Plains             

 

O:  3AUG2017 06:37:25  37.5N   78.4W MD=2.3  EMSC   VIRGINIA                     

P:  7AUG2017 109444    37.0N   77.0W 2.0-4.1 BAAAA  Kentucky/Tennessee/NC      

 

 

MODERATE EARTHQUAKE SHAKES OKLAHOMA CITY, OKLAHOMA

 

EARTHQUAKE SUMMARY FOR AUGUST 2, 2017

 

A moderate earthquake of M 4.2 was widely felt in Oklahoma today and was centered near Edmond and Oklahoma City. NEIC reported maximum intensity V in Edmond and Arcadia and IV in Oklahoma City, Jones, Spencer, Guthrie, Luther, Wellston, and II-III in Harrah, McLoud, Mustang, Meeker, Norman, El Reno, Stillwater, Shawnee, Seminole, Hydro, Ada, Sand Springs, Sapulpa, Beggs, Mounds, Tulsa, Bixby, Barnsdall, Broken Arrow, Owasso, Bartlesville, Oologah and Whitefield, Oklahoma. It was also reported felt with intensity II-III in Kansas at Belle Plaine, Wichita, and Gardner and possibly in Arkansas and Tennessee.

Elsewhere in Oklahoma light earthquakes of M 2.6 wer felt in Mooreland, of M 2.6 in Edmond and Arcadia and Norman, Oklahoma and as an M 3.3 in Edmond, Oklahoma City, Guthrie and Arcadia.

 

The M 4.2 was within about 10 km of Oklahoma City, the largest within about 50 km of that epicenter during the current year - 2017. Two other events of M 4.2 have occurred in Oklahoma this year - on May 13 and July 14. The last earthquake within about 50 km of this epicenter with M>4.2 was an M 4.5 on December 7, 2013 and an M 4.4 on October 13, 2010. These are the largest earthquakes in the area after the current activation began in 2010. Forecast 109474 had expected today's event was likely around August 6. There were some precursory effects noted in this summary in Oklahoma indicating a high level of stress. For example in the previous summary it was noted:

 

"NEIC reported an earthquake of M 3.4 in Kansas was felt with intensity IV in Caldwell and II-III in the area(s) of Mayfield and Wichita, Kansas.  This earthquake occurred 11.4 minutes after the M 5.6 in Argentina and at a distance of 71 degrees. The p-wave from Argentina would have been coincident with the Kansas earthquake and probably triggered it." (August 1-2, 2017)

 

O:  2AUG2017 20:45:26  35.7N   97.4W ML=3.3  EMSC   OKLAHOMA                     

O:  3AUG2017 02:56:37  35.7N   97.4W Mw=4.2  EMSC   OKLAHOMA CITY AREA, OKLAHOMA 

O:  2AUG2017 22:16:38  35.7N   97.4W mb=2.6  EMSC   OKLAHOMA                     

O:  2AUG2017 07:49:33  35.7N   97.4W mb=3.0  EMSC   OKLAHOMA                     

O:  3AUG2017 06:40:44  35.7N   97.4W mb=3.5  EMSC   OKLAHOMA CITY AREA, OKLAHOMA 

P:  6AUG2017 109474    35.0N   97.0W 2.0-4.1 BAAAA  Southern Plains            

 

Another moderate earthquake occurred in the region near Tokyo, Japan today. This event of M 4.5 was reported by NEIC to have been felt with maximum intensity IV in Tsuchiura, Ibaraki; Kawaguchi, Saitama; Oizumi, Gunma; and as far as 75 km from the onshore epicenter. Intensity II-III was also reported felt in Kasukabe, Nake, Kashiwa, Koga, Soka, Inzai, Matsudo, Ichikawa, Chiba, Narashino, Narita, Hoya, Tokyo, Tokorozawa, Itsunomiya Tochigi, Musashino, Chiba, Thomisato, Mitaka, Komae, Kawasaki, Kanagawa, Yokohama, Sagamihara, and Hitachi among other communities. As noted in the previous summary, this activity may be driven by stresses from Typhoon Noru:

 

"They may reflect stresses from Super-Typhoon Noru which is current south of Honshu, Japan and may turn north and pass over the island leading to a stronger earthquake in the next week. This summary had expected associated activity with Noru as follows: (August 2, 2017)

 

"Super Typhoon Noru continued today South of Honshu, Japan with winds up to 125 kts. It is expected to continue on the unusual track to the south along the  Volcano-Mariana arc over the next several days. Unusual stresses are placed on the earth when tropical storms run counter to the normal track direction and and help promote strong earthquakes in their unusual wake. Normally storms in this region track to the northeast, so Noru is a strong exception to the normal tracking and could trigger  a moderate to large regional event." (August 1, 2017)

 

Forecast 109453 had expected this activity was likely around August 4.

 

O:  3AUG2017 04:45:05  36.1N  139.9E mb=4.5  EMSC   EASTERN HONSHU, JAPAN        

P:  4AUG2017 109453    36.0N  142.0E 4.0-5.4 AABAA  Off East Coast Honshu      

 

A moderate earthquake in northeastern India was also widely felt today. This event of M 5.2 was reported felt with maximum intensity IV in Dharmanagae, Tripura, India and II-III in Gauhati, Dispur, Lala, Hailakandi, Silchar and Lumding, Assam and in Mawlai, Meghalaya, Champhai, Aizawi, Mizoram, and in Churachandpur, Moirang and Manipur, India. This is the strongest earthquake in eastern India since an M 5.6 in the India-Bangladesh area of January 3, 2017. Forecast 109163 had expected the area would see a moderate earthquake at the end of July or in early August.

 

O:  2AUG2017 18:18:07  24.3N   93.6E mb=5.2  EMSC   MANIPUR, INDIA REGION        

P: 29JUL2017 109163    23.0N   95.0E 4.0-5.6 BBAAA  Myanmar                    

 

The activity in the Southern Mid-Atlantic Ridge continued today with an M 5.0. This is a remote area and this event was not reported felt. It follows an M 5.1 on August 1, 2017. This epicenter is within about 250 km of the antipode of the M 7.7 in the Komandorsky Islands of July 17 and was probably triggered by volcanism on the South Mid-Atlantic Ridge triggered by antipodal effects of the Komandorsky great shock.  This is a classical example of antipodal triggering after a major earthquake. Other than the M 5.1 on August 1, the last earthquake of M>=5 within about 250 km of this epicenter in the Southern Mid-Atlantic Ridge occurred on  August 29, 2016 and prior to that on June 27, 2015 both with M 5.2-5.4. Forecast 109617 had expected activity in this region was likely around August 4.

 

O:  2AUG2017 16:16:32  53.8S    5.0W mb=5.0  EMSC   SOUTHERN MID-ATLANTIC RIDGE  

P:  4AUG2017 109617    55.0S    2.0E 4.0-5.4 ABCAA  Atlantic-Indian Ridge      

 

MODERATE EARTHQUAKES CONTINUE IN CHILE

 

EARTHQUAKE SUMMARY FOR AUGUST 1, 2017

 

The M 5.6 in Argentina yesterday was followed today by a second M 5.6 about 500 km to the southwest in the Santiago, Metropolitana region of Chile. NEIC reported it was felt with intensity V more than 100 km from the epicenter ar San Bernardo, Talagante, Limache, Quilpue, Valparaiso, and IV in Lampa, Santiago, Los Andes, Puente Alto, Penaflor, Buin, El Monte, Paine, Quillota, Melipilla, Vina del Mar and II-III in Graneros, San Antonio, Rancagua, Santa Cruz, Molina, Talca, Coihueco, Concepcion, and as far as 500 km from the epicenter.

CSN reported this earthquake was felt with intensity VI in  Santiago, Melipilla, Penaflor; V Paine, El Monte, Caragena, El Quisco, Tl Tabo, Quillota, San Antonio, Santo Domingo, Villa Alemana, Zapallar, Puento Alto, Talaganet, Til Til, Coltauco, Navidad; IV La Ligua, Llayllay, Quilpue, San Felipe, Valparaiso, Las Cabras, Mostazal, Rancagua, San Fernando, Santa Cruz, III Los Vilos, Salamanca, Curico; II Illapel, Lituece, Pencahue, Talca. Felt in the regions of Coquimbo, Valparaiso, Santiago, and Maule, Chile. No major damage was reported with this widely felt earthquake. The last earthquake within about 200 km of this epicenter with M>=5.6 was felt on August 13, 2014 with M 6.4. That event may have been a foreshock to the M 8.3 about 150 km to the north on September 16, 2015. Forecast 109601 had expected a regional event with magnitude up to M 5.6 was likely to the south in early August. This is possibly a regional aftershocks of the M 5.6 which hit beneath Argentina on August 1. This event is located at the seventh node (51-52 degrees) from the earthquakes of M 6.8 in Guatemala in June and may have been promoted from that source.

 

O:  2AUG2017 07:15:12  33.3S   70.3W mb=5.6  EMSC   REGION METROPOLITANA, CHILE  

O:  2AUG2017 07:15     33.2S   70.6W mb=5.4  GUC    Santiago, Melipilla, Penaflor;

P: 28JUL2017 109331    34.0S   73.0W 4.0-5.7 BABAA  Central Chile              

P:  5AUG2017 109601    35.0S   72.0W 4.0-5.6 BBAAA  Central Chile              

 

In the previous issue of this summary the earthquake in Argentina had been noted as:

 

"An earthquake of M 5.6 hit below Argentina today. GUC reported it was felt in

Chile with intensity V in Alto del Carmen and Vallenar; IV in Freirina and III in Copiapo, Tierra Amarilla, La Higuera, La Serena, Paiguano and Vicuna. Also felt in the regions of Atacama and Coquimbo, Chile. NEIC reported it was felt with intensity II in Rio Cuarto, Cordoba, Argentina. No damage was reported. While an M 6.4 occurred in Argentina on February 18, 2017 that epicenter was more than 500 km to the north of today's. The current quake is the largest within about 250 km of the epicenter since an M 5.7 and M 6.2 on November 13, 2016 and may be an aftershock of those events. Forecast 109587 had expected this event in Argentina was likely around August 3." (August 1, 2017)

 

 

CSN reported this earthquake was felt with intensity V in  Alto del Carmen, Vallenar; IV Freirina; III Copiapo, Tierra Amarilla, La Higuera, La Serena, Paiguano, Vicuna, Felt in Atacama dn Coquimbo, Chile.

 

O:  1AUG2017 06:13:52  28.6S   68.7W Mw=5.6  EMSC   LA RIOJA, ARGENTINA          

O:  1AUG2017 06:13     28.5S   69.3W mb=5.7  GUC    Alto del Carmen, Vallenar; IV

P:  3AUG2017 109587    28.0S   67.0W 4.0-5.6 AABAA  Argentina                  

P:  7AUG2017 109587    28.0S   68.0W 4.0-5.6 CAAAA  Argentina                  

P: 30JUL2017 109317    28.0S   67.0W 4.0-5.7 AABAA  Argentina                  

 

 

NEIC reported an earthquake of M 3.4 in Kansas was felt with intensity IV in Caldwell and II-III in the area(s) of Mayfield and Wichita, Kansas. This earthquake occurred 11.4 minutes after the M 5.6 in Argentina and at a distance of 71 degrees. The p-wave from Argentina would have been coincident with the Kansas earthquake and probably triggered it.

 

O:  1AUG2017 06:25:12  37.1N   97.6W mb=3.4  EMSC   KANSAS                       

O: 01AUG2017 06:25:12  37.1N   97.6W mb=3.4  ANSS   N of Caldwell Kansas

P: 29JUL2017 109216    38.0N   99.0W 2.0-3.9 AAAAA  Southern Plains            

 

An earthquake of M 4.8 in Romania was widely felt today. NEIC reported maximum intensity IV in Bacau and II-III in Boldesti-Scaeni, Sinaia, Bucharest, Galati, Iasi, Izmayil, Ukraine and Chisinau, Moldava. A smaller foreshock earlier in the day of M 4.3 was reported felt with intensity IV in Buzau; III in Onesti and II in Bucharest, Romania. Like recent strong activity in Crete (M 5.3) and the Dodecanese Islands, Greece (M 6.7) these earthquakes in Romania may have been promoted by the strong tidal stresses associated with the new moon as noted in this summary in previous issues:

 

"The new moon will arrive on July 23 at 09:46 UT. Longitudes which are sub-solar at this time center around 35 East longitude ..  eastern Europe" (July 21-27, 2017)

 

The last earthquake in Romania with M>=4.8 occurred on December 27, 2016 and September 23, 2016 each with M 5.6. The area had been quiet previously at this magnitude level since October, 2013.  Forecast 109515 had expected today's event was likely in early August in Romania. Most earthquakes in Romania occur at an intermediate depth, and are felt at the surface with little associated damage.

 

O:  2AUG2017 02:32:12  45.5N   26.4E mb=4.8  EMSC   ROMANIA                       

O:  1AUG2017 10:27:51  45.5N   26.5E mb=4.3  EMSC   ROMANIA                      

P:  5AUG2017 109515    46.0N   27.0E 3.0-5.1 BAAAA  Romania/NW Turkey          

 

The second strongest quake in the world today occurred as an M 5.3 north of

Tokyo, Japan. It was followed by an M 4.8 nearer Tokyo. These events were widely felt. NEIC reported this earthquake of M 4.8 north of Tokyo, Japan  was felt with intensity V in Iwai, Ibaraki, Asaka, Saitama,  and Oyama, Tochigi and IV in Moka, Narita, Wako, Ageo, Tsuchiura, Japan and II-III in the area(s) of Tsukuba, Naka, Toride, Kashiwa, Shanan, Chiba, Koga, Moka, Kamagaya, Matsudo, Hatogaya, Kawaguchi, Saitama, Funabashi, Narashino, Hanyu, Mito, Utsunomiya, Kawagoe, Tokyo, Chiba, Miyoshi, Oi, Kumagaya, Oizuni, Tokorozawa, Mitaka, Iruma, Komai, Kawasaki, Hitachi, Yokohama, Hachioji, Yamato, Sagamihara, Kimitsu, Maebashi, Gunma, Takasaki, Kamakura, Yokosuka and Komono, Nagano up to 150 km from the epicenter. A foreshock of M 5.0 to the north of this earlier in the day was felt with intensity VI in Hitachi and Hitachinaka, Ibaraki; V in Tokai, Tsukuba, Tsuchiura, Naka, Toride, Shawa, Kasukabe, Mito, Kasukabe, Nagareyama,  and IV Oizumi, Saitama, Chiba, Ayase, Kashiwa, Tomisate, Chiba, in Aizuwakamatsu, Oarai, Ujiie, Utsunomiya, and in general within about 200 km of the epicenter. They may reflect stresses from Super-Typhoon Noru which is current south of

Honshu, Japan and may turn north and pass over the island leading to a stronger earthquake in the next week. This summary had expected associated activity with Noru as follows:

 

"Super Typhoon Noru continued today South of Honshu, Japan with winds up to 125 kts. It is expected to continue on the unusual track to the south along the  Volcano-Mariana arc over the next several days. Unusual stresses are placed on the earth when tropical storms run counter to the normal track direction and and help promote strong earthquakes in their unusual wake. Normally storms in this region track to the northeast, so Noru is a strong exception to the normal tracking and could trigger  a moderate to large regional event." (August 1, 2017)

 

The M 5.3 is the first event at this magnitude or greater within about 100 km of this epicenter since January 4, 2017 when an M 5.2 was recorded. The last of larger magnitude occurred on December 28, 2016 with M 5.9.  Forecasts 109453 and 109196 had expected this activity in late July or early  August.

 

O:  1AUG2017 17:02:06  36.8N  140.7E mb=5.3  EMSC   NEAR EAST COAST OF HONSHU, JAP

P:  4AUG2017 109453    36.0N  142.0E 4.0-5.4 BAAAA  Off East Coast Honshu      

 

O:  1AUG2017 22:15:56  36.1N  140.0E mb=4.8  EMSC   NEAR EAST COAST OF HONSHU, JAP

P:  4AUG2017 109453    36.0N  142.0E 4.0-5.4 BABAA  Off East Coast Honshu      

P: 30JUL2017 109196    35.0N  139.0E 3.5-5.0 ABAAA  No. Honshu, Japan          

 

The strongest earthquake in the U.S. or Canada today was an M 3.9 in southern Alaska. NEIC reported it was felt with intensity IV in Willow, Alaska and II-III in Chugiak, Fort Richardson, Anchorage, Eagle River, Talkeetna, Palmer and Moose Pass, Alaska. The last earthquake within about 100 km of this epicenter with M>=3/9 was an M 4.6 on May 29, 2017. Forecast 109288 had expected this event was likely around July 30.

 

O:  1AUG2017 09:35:26  61.7N  149.7W ML=3.9  EMSC   SOUTHERN ALASKA              

P: 30JUL2017 109288    60.9N  151.1W 3.2-5.0 AAAAA  Central Alaska             

 

The strongest earthquake near the U.S. outside Alaska was an M 3.6 off the coast of Baja California. This continued the activation of this region following the M 6.7 in Greece of July 20. The area is at 103 degrees from Greece and this activation was probably promoted by concentrated seismic energy from that source. Forecasts 109458 and 109205 had expected this activity at the end of July or in early August. Other earthquakes of 103-104 degrees from Greece occurred today in the South Sandwich Islands (M 4.8) and in Guatemala (M 4.1).

 

O:  1AUG2017 11:00:07  31.3N  116.8W ML=3.6  EMSC   OFFSHORE BAJA CALIFORNIA, MEXI

P:  1AUG2017 109458    32.1N  116.4W 2.5-4.5 AAAAA  So. California             

P: 31JUL2017 109205    31.9N  116.3W 2.5-4.4 AAAAA  So. California             

 

An unusually large earthquake occurred in the North Atlantic today. This is an aftershock of the unprecedented earthquake at this epicenter of  July 27 as noted in that day's summary:

 

"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)

 

O:  2AUG2017 00:16:12  13.5N   49.4W Mw=5.2  EMSC   NORTH ATLANTIC OCEAN         

P:  7AUG2017 109396    15.0N   46.0W 4.0-6.1 BBCAA  Mid-Atlantic Ridge         

 

MODERATELY STRONG QUAKE SHAKES CHILE AND ARGENTINA

 

EARTHQUAKE SUMMARY FOR JULY 31, 2017

 

An earthquake of M 5.6 hit below Argentina today. GUC reported it was felt in

Chile with intensity V in Alto del Carmen and Vallenar; IV in Freirina and III in Copiapo, Tierra Amarilla, La Higuera, La Serena, Paiguano and Vicuna. Also felt in the regions of Atacama and Coquimbo, Chile. NEIC reported it was felt with intensity II in Rio Cuarto, Cordoba, Argentina.

No damage was reported. While an M 6.4 occurred in Argentina on February 18, 2017 that epicenter was more than 500 km to the north of today's. The current quake is the largest within about 250 km of the epicenter since an M 5.7 and M 6.2 on November 13, 2016 and may be an aftershock of those events. Forecast 109587 had expected this event in Argentina was likely around August 3.

 

O:  1AUG2017 06:13:52  28.6S   68.7W Mw=5.6  EMSC   LA RIOJA, ARGENTINA          

P:  3AUG2017 109587    28.0S   67.0W 4.0-5.6 AAAAA  Argentina                  

 

An M 5.3 in Crete, Greece was the strongest earthquake today. NEIC reported it was felt with intensity II-III in Palaiokhora, Khania, Ayia Marina, Kolimvari, Hania Greece and in Rodos, Dodecanese Islands, Greece. This is probably regional activity caused by stress redistribution following the M 6.7 Dodecanese Islands, Greece quake of July 20. No damage or casualties were reported with today's event. The last earthquake in Crete of larger magnitude was a simlar M 5.3 on July 15, 2017 about 100 km east of today's epicenter. The last of significantly larger magnitude occurred on June 16, 2013 with M 6.0. An M 5.4 occurred about 200 km east of this on May 25, 2016.  Forecast 109185 had expected today's event was likely within about 50 km  of this epicenter around July 29. This event is located at 102 degrees from the June events in Guatemala of M 6.9 and was probably promoted from that source.

 

O: 31JUL2017 21:29:12  34.5N   24.0E mb=5.2  EMSC   CRETE, GREECE                

O: 31JUL2017 21:29:11  34.4N   24.0E mb=5.3  ANSS   SSE of Palaiochora Greece

P: 29JUL2017 109185    34.0N   24.0E 3.0-4.7 AAAAA  Crete                      

 

The strongest earthquakes in the U.S. or Canada today was an M 4.8 in the eastern Fox Islands region followed by an M 5.1 in the Andreanof Islands, Alaska. of  Alaska. NEIC reported it was felt with intensity IV in Akutan and II in Unalaska, Alaska. The Fox Islands, Alaska quake was joined by a near-antipodal event of M 5.1 on the mid-Southern Atlantic ridge. This earthquake which is truly antipodal to the Rat Islands was not reported felt in this remote epicentral area. The event in the Andreanof Islands was about 300 km east of the true antipode of the South Atlantic earthquake and occurred 37 minutes after that event. There are many core and surface reflections arriving at the antipode at this time and they may have helped promoted the Andreanof Islands earthquake. These events area at 103 degrees from the New Zealand quake of July 11 (M 6.9) and may have been promoted at this distance where seismic energy is concentrated following large quakes. Like the earthquake in Crete and an M 3.9 in Sakhalin today, this epicenter is also at 100-102 degrees from the Guatemala earthquakes of June, 2017.

 

O:  1AUG2017 04:23:26  53.1S    5.0W mb=5.1  EMSC   SOUTHERN MID-ATLANTIC RIDGE  

P: 31JUL2017 109340    55.0S    2.0E 4.0-5.4 ABCAA  Atlantic-Indian Ridge      

 

The last major activity in the Andreanof Islands occurred May 8-10 with an M 6.4 about 150 km west of today's epicenter. July has been a quiet month in the area with the strongest an M 4.3 on July 14 in the eastern Andreanof Islands. Forecast 109265 had expected today's activity was possible around July 30.

 

O:  1AUG2017 05:00:25  52.0N  176.3W mb=5.2  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

O: 01AUG2017 05:00:26  51.9N  176.3W mb=5.2  ANSS   E of Adak Alaska

O: 01AUG2017 05:00:24  51.5N  176.1W ml=5.1  ANSS   Aleutians, Alaska

P: 30JUL2017 109265    51.8N  178.0W 3.5-5.1 AAAAA  Andreanoff Isls, Aleutians 

 

The earthquake of M 4.8 in the eastern Fox Islands was the largest within about 200 km of this epicenter during the current year. The last earthquake in this area of M>=4.8 occurred on October 27, 2016 about 200 km southeast of today's epicenter with M 5.8. Forecasts 109534 and 109270 had expected this event was likely at the end of July or in early August.

 

O: 31JUL2017 09:02:57  54.1N  165.4W mb=4.8  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

P:  2AUG2017 109534    53.5N  165.8W 3.5-5.2 AAAAA  Fox Islands, Aleutians     

P: 31JUL2017 109270    53.6N  166.1W 3.5-5.3 AAAAA  Fox Islands, Aleutians     

 

HAWAII SHAKES POSSIBLY RELATED TO TROPICAL STORMS FERNANDA AND GREG

 

EARTHQUAKE SUMMARY FOR JULY 30, 2017

 

The strongest earthquake in the U.S. or Canada today was an M 4.2 in Hawaii. NEIC reported it was felt with intensity II-III in Hawaii at Hawi, Hana, Kula, Kapaau, Kihei, Makawao, Haiku, Waikoloa, Paia, Kahului, Kamuela, Honokaa, Wailuku, Kailua Kona, Paauilo, Holualoa, Kealakekua, Kaunakakai, Hilo, Papaikou, Kualapuu, Honolulu and Kailua and in general within about 200 km of the epicenter. The last earthquake within about 100 km of today's event, and the only such quake during the current year, 2017, was an M 4.7 on February 17, 2017. An M 5.2-5.3 about 150 km to the south on June 8 was probably not related to today's event. In the past several days tropical storms and hurricanes have made close approaches to Hawaii. These may have added stresses to the region which resulted in today's tectonic earthquake. For example, TS Greg and prior to that Fernanda passed near Hawaii in the past several days and threatened seismicity as noted in previous issues of this report:

 

"TS    GREG     2017-07-25  00:00 UT  15.0N  155.4W  050 kts  Eastern Pacific         

 

TS Greg (TD 07E) continued today in the eastern Pacific south of Hawaii with winds up to 050 kts. It is expected to track to the west over the next week into the Pacific and not to encounter land." (July 24-27, 2017)

 

and

 

"Hurricane Fernanda continued today in the eastern Pacific with winds up to 45 kts. It is expected to ... This storm appears to be headed for Hawaii where it may bring moderate seismicity and/or volcanism." (July 24, 2017)

 

Forecasts 109159 and 109411 had expected this activity in Hawaii was likely

at the end of July or in early August.

 

O: 30JUL2017 12:01:06  20.4N  156.1W ml=4.2  ANSS   WNW of Hawi Hawaii           

O: 30JUL2017 12:01:06  20.4N  156.1W ML=4.2  EMSC   MAUI REGION, HAWAII          

P: 30JUL2017 109159    20.4N  155.1W 4.0-5.4 AAAAA  Hawaii area                

P:  8AUG2017 109411    20.3N  156.6W 4.0-5.6 CAAAA  Hawaii area                

 

The strongest earthquake in the world today was an M 5.7 in the Central Kuril Islands. This followed an M 5.3 in the region of Tokyo, Japan. In both cases these are unusually large events in an area which has seen mostly moderate seismicity since aftershocks of the March 11, 2011 M 9 quake and tsunami. This and other recent activity may indicate a return to higher background rates and "normal" regional seismicity. It may also be seismicity related to the beginning of Typhoon season. For example Typhoon Noru was updated today to a Super Typhoon with winds up to 160 kts. This intensity can be a strong stressor on the earth leading to possibly strong earthquakes as noted in this summary:

 

"Super Typhoon Noru continued today in the Volcano Islands region with winds up to 160 kts. It is expected to continue on the unusual track to the south along the  Volcano-Mariana arc over the next several days. Unusual stresses are placed on the earth when tropical storms run counter to the normal track direction and and help promote strong earthquakes in their unusual wake. Normally storms in this region track to the northeast, so Noru is a strong exception to the normal tracking and could trigger  a moderate to large regional event." (July 29-30, 2017)

 

The strongest earthquake this year in the Kuril Islands occurred a month ago on June 28 in the southern Kurils about 500 km southwest of today's epicenter with M 5.8. The last earthquake of M>=5.7 within about 250 km of today's event occurred on November 14, 2014 (M 5.7) and November 25, 2013 (M 5.8). These may have been aftershocks of an M 7.2 of April 19, 2013 within about 50 km of today's event.  Forecast 109256 had expected a moderate to moderately strong earthquake within about 150 km of this epicenter was likely around July 31.

 

O: 30JUL2017 21:00:48  46.2N  151.0E Mw=5.7  EMSC   KURIL ISLANDS                

P: 31JUL2017 109256    45.0N  152.0E 3.5-5.4 ABAAA  So. Kurils                 

 

O: 30JUL2017 22:33:43  48.4N  153.8E mb=4.3  EMSC   KURIL ISLANDS                

P: 31JUL2017 109256    49.0N  152.0E 3.5-5.4 AAAAA  So. Kurils                 

 

The earthquake of M 5.3 north of Tokyo, Japan today was widely felt in the area.

NEIC reported this earthquake of M 5.3 in Japan was felt with intensity II-III in the area(s) of Tsuchiura, Ibaraki and in Tokyo, Japan.  It is the strongest quake within about 100 km of this epicenter since an M 5.7 on November 14, 2014. The strongest this year in the region was an M 5.2 on January 4, 2017.  Forecast 109200 expected it within about 100 km around July 28.

 

O: 30JUL2017 12:45:05  36.2N  143.7E Mw=5.3  EMSC   OFF EAST COAST OF HONSHU, JAPA

O: 30JUL2017 14:28:51  36.6N  141.0E mb=4.3  EMSC   NEAR EAST COAST OF HONSHU, JAP

P: 28JUL2017 109200    36.0N  142.0E 4.0-5.6 AAAAA  Off East Coast Honshu      

 

ANTIPODAL PAIRS IN COLOMBIA/SUMATRA AND NEW ZEALAND/SPAIN

 

EARTHQUAKE SUMMARY FOR JULY 29, 2017

 

A series of antipodal pairs hit at least two areas today. The strongest of these followed an earthquake in Sumatra, Indonesia of M 5.5 on July 25 and occurred as  a pair of moderate events in Colombia today.  These events of M  4.5 and 4.7 were reported by NEIC to have been felt with intensity VI in Murillo, Tolima, Colombia and II-III in Villamaria, Pereira and Bello, Colombia.  This summary had anticipated these events as an antipodal response to the M 5.5 in Sumatra as follows:

 

"The strongest earthquake in the world today was an M 5.5 southwest of Sumatra, Indonesia. It was not initially reported felt and was followed by moderate aftershocks  of M 4.5 and 4.9. The last earthquake of M>=5.5 in this region was an M 5.5 on March 7, 2017 about 50 km southeast of today's epicenter. Forecast 109121 had expected this event within about 100 km of the epicenter, likely around July 28. Today's event follows a near-antipodal M 5.0 in Colombia two days ago. Antipodal pairs in these two regions are common especially at times of high geomagnetic activity." (July 26, 2017) 

 

O: 25JUL2017 23:23:24   5.6S  101.5E Mw=5.5  EMSC   SOUTHWEST OF SUMATRA, INDONESI

O: 25JUL2017 23:57:49   5.7S  101.4E mb=4.9  EMSC   SOUTHWEST OF SUMATRA, INDONESI

O: 26JUL2017 00:21:50   5.8S  101.3E mb=4.5  EMSC   SOUTHWEST OF SUMATRA, INDONESI

P: 28JUL2017 109121     5.0S  102.0E 4.0-5.6 BAAAA  So. of Sumatera            

 

O: 27JUL2017 19:24:49   4.4S  102.0E mb=5.1  EMSC   SOUTHERN SUMATRA, INDONESIA  

P: 28JUL2017 109121     5.0S  102.0E 4.0-5.6 AAAAA  So. of Sumatera            

 

The earthquakes in Colombia followed an M 5.7 about 150 km southeast of these epicenters which occurred on February 6, 2017 and may be regional aftershocks of that event. The last event within about 100 km of these epicenters of M>=4.

occurred April 29 with  M 5.0. Forecast 109095 had expected today's earthquake was likely around July 31. These epicenters are at 101-102 degrees from the M 7.7 in the Komandorsky Islands of July 17 and may have been promoted from that source.

 

O: 30JUL2017 05:57:02   4.8N   75.3W Mw=4.5  EMSC   COLOMBIA                     

O: 30JUL2017 05:40:41   4.9N   75.0W mb=4.7  EMSC   COLOMBIA                      

P: 31JUL2017 109095     5.0N   76.0W 4.0-5.5 AAAAA  Colombia                   

 

A moderate M 4.5 earthquake in North Island, New Zealand was followed by an M 3.1 lightly felt event in Spain near the antipode.  GEONET reported the M 4.5 was felt with light intensity northeast of Whanganui and in southwestern North Island and northern South Island. Light to moderate intensity was reported throughout much of southern and western North Island and northern South Island. More than 189 people reported feeling this earthquake with weak or light intensity; 17 with moderate; and none with strong to extreme shaking. Forecast 109337 and 109333 had expected the event in New Zealand was likely around July 28-30. The earthquake in Spain had been anticipated to occur in early August within about 150 km of this epicenter in forecast 109447.

 

O: 29JUN2017 16:15:16  39.7S  175.2E MS=4.5  GEONET Felt with light intensity    

P: 28JUL2017 109333    39.0S  176.0E 3.0-4.6 AAAAA  North Island, N.Z.         

P: 30JUL2017 109337    40.0S  176.0E 3.0-4.6 AAAAA  North Island, N.Z.         

 

O: 30JUL2017 06:56:29  37.9N    2.4W ML=3.1  EMSC   SPAIN                        

P:  6AUG2017 109447    37.0N    4.0W 3.5-4.9 CAAAA  Morocco/Spain              

 

The strongest earthquakes of the day occurred as an M 5.3 quake in the Lake Edward region of Uganda. NEIC reported it was widely felt throughout Uganda with intensity II-III in Uganda at Katwe, Mbarara, Fort Portal, Kisoro, Kigali, Masaka, Lukaya, Entebbe, Kampala, Kireka and Bweyogerere, Central and western Uganda. The only moderate earthquake in Uganda during the year 2017 has been an M 4.7 in the Lake Albert region on February 25. The last earthquake of M>=5.3 in the area within about 200 km of today was an M 5.9 on September 10, 2016. The last event in the Lake Edward area of M>=5.3 was an M 5.3 on June 29, 2001. This, along with the M 6.7 in Greece of July 20 (near the same longitude) may be related to excess tidal stress associated with the last new moon as noted in this summary:

 

"The new moon will arrive on July 23 at 09:46 UT. Longitudes which are sub-solar at this time center around 35 East longitude while those which are anti-solar are near 145 West longitude. These include the East African Rift" (July 21-28, 2017)

 

O: 30JUL2017 07:02:29   0.3S   29.8E mb=5.3  EMSC   LAKE EDWARD REGION, UGANDA   

P: 18JUL2017 108851     2.0S   29.0E 3.0-4.6 DBAAA  Lake Victoria area         

 

The strongest earthquake in the U.S. or Canada today was an M 4.4-4.6 aftershock of the M 5.1 off the coast of Northern California which occurred yesterday. Today's event was reported by NEIC to have been felt with intensity II-III in California at Samoa, Eureka, McKinleyville, Arcata, Korbel, Crescent City.

Forecast 109507 had expected this activity within about 100 km of this epicenter was likely in late July or early August.

 

O: 29JUL2017 17:08:24  41.1N  125.4W Mw=4.4  EMSC   OFFSHORE NORTHERN CALIFORNIA 

O: 29JUL2017 17:08:26  41.1N  125.3W mw=4.6  ANSS   106km WNW of Eureka

P:  1AUG2017 109507    41.8N  126.9W 2.5-4.4 AABAA  Off Coast of No. Calif     

P:  2AUG2017 109507    40.3N  124.7W 2.5-4.5 BAAAA  Off Coast of No. Calif     

 

An earthquake near Hutchinson, central Kansas was widely felt with light intensity today.

NEIC reported this earthquake of M 3.0 in Central Kansas was felt with intensity II-III in the area(s) of South Hutchinson, Hutchinson, Inman, Sylvia, and Cheney, Kansas.  This epicenter is somewhat unusual in the current series of earthquakes affecting the mid-section of the U.S. central Plains states. It is the largest within  about 50 km of this epicenter in the past 25 years. Earthquakes of M 3.5 hit the region on August 19, 2016 about 60 km southeast of this and an M 3.0 hit about 100 km to the southwest on July 24, 2001. This appears to have been the first of the precursors to the modern regional seismicity. This summary had expected a shift in regional tectonics was likely in 1999 or 2000. Forecast 109216 had expected today's event around July 29.

 

O: 30JUL2017 00:13:44  38.0N   98.0W mb=3.0  EMSC   KANSAS                       

P: 29JUL2017 109216    38.0N   99.0W 2.0-3.9 AAAAA  Southern Plains            

 

An unusual earthquake of M 4.4 was also felt in the region of Cuba today. NEIC reported this earthquake of M 4.4 in Cuba was felt with intensity V in the area(s) of Varadero, Matanzas, Cuba. Most recent activity in the area has occurred south of the Island, so today's event north of Cuba is out of the ordinary. Two earthquakes west of this occurred on January 9, 2014 and on March 9, 2014, both about 150 km east of today's epicenter and were the only such events within about 200 km of this epicenter in the past 25 years.

 

O: 30JUL2017 03:41:32  23.3N   81.6W mb=4.4  EMSC   CUBA REGION 

 

UNPRECEDENTED M 5.9 LOCATED IN NORTH ATLANTIC SEAFLOOR

 

EARTHQUAKE SUMMARY FOR JULY 27, 2017

 

The strongest earthquake of the day was an M 5.9 in the North Atlantic Ocean. NEIC reported it may have been felt with intensity III in Bulkeley, Saint George, Barbados direct to the west of the epicenter on the Northern Mid-Atlantic Ridge. This may be an erroneous felt report.

 

A tropical storm may be forming in the Central Mid-Atlantic area. This system is currently located at 10N 38W and moving to the west. NHC expects it to develop into a tropical storm within five days with 30% probability. The M 5.9 in the central mid-Atlantic may have been promoted by stresses from this storm.

 

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.

 

O: 27JUL2017 17:53:26  13.5N   49.2W Mw=5.9  EMSC   NORTH ATLANTIC OCEAN         

P: 29JUL2017 109144    15.0N   45.0W 4.0-5.9 ABCAA  Mid-Atlantic Ridge         

 

The antipodal area of the event in the North Atlantic was also active today. An M 5.8 in the Buru, Indonesia region preceded the Atlantic event by about 5 hours at a distance of 170 degrees. An M 4.9 in the Seram area of Indonesia occurred about 174 degrees from the Atlantic epicenter. The event in Buru is the strongest within about 200 km of this epicenter since an M 6.4 on June 5, 2016

and prior to that an M 6.0 on May 2, 2014.  Forecast 109123 had expected this event was likely as a regional earthquake around July 29. This epicenter is near the 103 degree distance from the M 6.7 in the Dodecanese Islands, Greece of July 20 and may have been promoted from that source.

 

 

O: 27JUL2017 12:08:37   3.6S  126.1E Mw=5.8  EMSC   BURU, INDONESIA              

P: 29JUL2017 109123     1.0S  123.0E 4.0-5.4 ACCAA  Sulawesi area              

 

O: 27JUL2017 13:55:17   3.9S  129.1E mb=4.9  EMSC   SERAM, INDONESIA             

P: 28JUL2017 109124     4.0S  131.0E 4.0-5.5 AABAA  West Irian, PNG            

 

A moderate earthquake of M 5.3 also hit in the Izu Islands south of Honshu, Japan today. It was not reported felt in this remote area. It was probably promoted by Typhoon Noru which had its eye about 150 km to the east of this epicenter at the time the earthquake occurred. This had been expected in previous issues of this report as:

 

"TYPH  NORU     2017-07-28  00:00 UT  29.5N  145.3E  080 kts  N Pacific Ocean      

 

Typhoon Noru continued today in the northwest Pacific Ocean with winds up to 080 kts. It is expected to track to the west reaching the Bonin Islands of southern Japan around July 28." (July 25-27, 2017)

 

The last earthquake within about 200 km of this epicenter in the Izu Islands with M>=5.3 occurred on October 4, 2016 with M 5.7.  Forecast 109212 had expected this earthquake within about 70 km of the epicenter was likely around July 29.

 

O: 27JUL2017 23:58:55  29.3N  143.0E Mw=5.3  EMSC   IZU ISLANDS, JAPAN REGION    

P: 29JUL2017 109212    30.0N  143.0E 4.0-5.6 AAAAA  So. of Honshu              

 

The strongest earthquake in the U.S. or Canada today was an M 3.5 in the Bakersfield region of southern/central California.  NEIC reported this earthquake of M 3.5 near Kernville, California  was felt with intensity II-III in the area(s) of Onyx, Weldon, Inyokern, Kernville, Lake Isabella, Bodfish, Caliente, Bakersfield, Clovis and generally within about 100 km of the epicenter. This is the strongest earthquake within about 50 km of this epicenter since an M 3.5 on June 4, 2015 and prior to that an M 3.6 on March 24, 2015.

Forecast 109209 had expected this event was likely in this area around July 27.

Like the events in Indonesia, this epicenter is near the 103 degree distance from the Dodecanese Islands, Greece and, along with other continuing activity in Southern California today,  may have been promoted from that source.

 

O: 28JUL2017 03:40:17  35.5N  118.4W ML=2.5  EMSC   CENTRAL CALIFORNIA           

O: 28JUL2017 00:48:48  35.6N  118.2W ML=3.5  EMSC   CENTRAL CALIFORNIA           

P: 27JUL2017 109209    35.8N  117.6W 2.5-4.4 AAAAA  So. California             

 

TROPICAL STORMS PUSH SEISMICITY IN ASIA; SOUTH AMERICA

 

EARTHQUAKE SUMMARY FOR JULY 26, 2017

 

A strong earthquake hit the Ryukyu Islands today with M 5.9-6.0. NEIC reported

it was felt in Okinawa with intensity II-III at Ishikawa, Okinawa, Chatan, Urasoe, Naha, Japan. This may be related to the approach of TS Nesat to the continental slope as noted in the previous issue of this report:

 

"A new Tropical Storm - TS Nesat -  formed today in the northwest Pacific Ocean with winds up to 055 kts. It is expected to track to the northwest reaching Taiwan around July 31. This storm is hitting the continental shelf off the northeastern Philippines at this time and motions induced from it could help promote seismicity further to the west in Taiwan and the Ryukyu Islands of Japan and perhaps later in Honshu." (July 25-26, 2017)

 

The last earthquake with M>=5.9 within about 200 km of this epicenter in the

Ryukyu Islands occurred on September 26, 2016 with M 6.0 and prior to that on May 27, 2015 with M 5.9. The last of larger magnitude was an M 6.5 on March 2, 2014 and on May 25, 2010. Forecast 109190 had expected it to the north around July 24. This is located at the third node (120 degrees) from the M 6.8 quakes in Guatemala of June 14 and 22, 2017 and may have been promoted from those sources.

 

 

O: 26JUL2017 13:27:47  26.9N  130.3E mb=4.7  EMSC   SOUTHEAST OF RYUKYU ISLANDS  

O: 26JUL2017 10:32:58  27.0N  130.1E Mw=5.9  EMSC   SOUTHEAST OF RYUKYU ISLANDS  

P: 24JUL2017 109190    30.0N  131.0E 3.5-5.0 ACAAA  Kyushu, Japan area         

 

A pair of moderate earthquakes of M 4.8 and 4.5 also were felt in Taiwan as  TS NESAT moved into the area. These were the first moderate earthquakes in  that area in more than a week. Forecasts 109169 and 109168 had expected this activity within about 100 km of the epicenters was likely around July 24-27. 

 

O: 26JUL2017 17:28:34  23.3N  121.6E ML=4.5  TAI    Hualien, Taiwan              

P: 24JUL2017 109169    22.0N  122.0E 4.0-5.4 AAAAA  Taiwan                     

 

CWB reported this earthquake was felt with intensity III in Taitung and II in Hualien Counties, Taiwan.

 

O: 27JUL2017 07:08:12  21.7N  121.5E ML=4.8  TAI    Hualien, Taiwan              

P: 27JUL2017 109168    22.0N  121.0E 4.0-5.4 AAAAA  Taiwan                     

 

CWB reported this earthquake was felt with intensity II in Taitung and I in Pingtung, Tainan, Chiayi and Yunlin Counties, Taiwan.

 

The earthquake in the Ryukyu Islands followed 22 minutes after an M 5.1 in Antofagasta, Chile. The distance between these epicenters is 162 degrees. PKP waves have a cusp at this time and distance and may have helped to trigger the quake in Japan. The event in Chile may also have been promoted by effects from tropical storms. A series of moderate earthquakes has hit this area in the past week as Tropical Storm Sonca passed near the antipode near Vietnam. This antipodal activity had been  expected in previous issues of this summary:

 

"TS SONCA (TD 08W) continued today east of Vietnam with winds up to 050 kts. It is expected to to the west dissipating over the next several days. It could help promote seismicity in southern Asia in the meantime. The antipode is at 17S 73W, an area of southern Peru, Bolivia and northern Chile which saw a strong earthquake three days ago and could see additional promoted seismicity in the next several days." (July 23-26, 2017)

 

An earthquake of M 3.8-4.3 also occurred nearer the forecast epicenter today near Antofagasta, Chile. Forecasts 109327 and 109317 had expected this activity in the Antofagasta region was likely around July 26, 2017.

 

CSN reported the earthquake of M 5.0-5.1 was felt with intensity IV in  Sierra Gorda, Antofagasta; III Calama, Maria Elena, San Pedro de Atacama, Diego de Almagro. Felt in Antofagasta and Atacama, Chile.

 

O: 26JUL2017 10:11     24.0S   69.5W mb=5.0  GUC    Sierra Gorda, Antofagasta; III

O: 26JUL2017 10:11:00  24.1S   69.4W Mw=5.1  EMSC   ANTOFAGASTA, CHILE           

P: 26JUL2017 109317    24.0S   67.0W 4.0-5.8 AABAA  Argentina                  

P: 21JUL2017 109059    24.0S   69.0W 4.0-5.4 BAAAA  Coast No. Chile            

 

CSN reported the earthquake of M 3.8-4.3 was felt with intensity III in  Alto Hospicio, Iquique, Felt in Tarapaca, Chile.

 

O: 26JUL2017 18:04:41  20.1S   70.1W mb=4.3  EMSC   TARAPACA, CHILE               

O: 26JUL2017 18:04     20.1S   70.1W mb=3.8  GUC    Alto Hospicio, Iquique, Felt i

P: 26JUL2017 109327    20.0S   71.0W 4.0-5.6 AAAAA  So. Peru/Bolivia           

 

A moderate earthquake of M 4.6 occurred in Iceland today and was followed by regional aftershocks in the M 3.0-4.0 range, including events of M 3.8, 3.9 and 4.0 about 150 km southwest of the M 4.6. It was not reported felt, nor were the aftershocks. The last, and only other earthquake of M>=4.5 within about 250 km of the mainshock during 2017 was an M 4.6 on April 10. Forecast 109291 had  expected this activity in Iceland within about 150 km of the mainshock was likely around July 27. Iceland is located at the sixth node (60 degrees) from the M 7.7 earthquake of July 17 in the Komandorsky Islands and may have been promoted from that source.

 

O: 26JUL2017 22:18:15  63.6N   19.1W mb=4.5  EMSC   ICELAND                      

P: 27JUL2017 109291    65.0N   18.0W 3.0-4.6 ABAAA  Iceland area               

 

O: 26JUL2017 11:40:01  63.9N   22.2W ML=3.9  EMSC   ICELAND REGION               

O: 26JUL2017 13:55:25  63.9N   22.2W ML=4.0  EMSC   ICELAND REGION               

O: 26JUL2017 13:59:54  63.9N   22.3W ML=3.1  EMSC   ICELAND REGION               

O: 26JUL2017 20:25:02  63.9N   22.3W ML=3.8  EMSC   ICELAND REGION               

P: 27JUL2017 109291    65.0N   18.0W 3.0-4.6 ABBAA  Iceland area               

 

The strongest earthquakes in the U.S. or Canada today occurred in two separate swarms in Southern California. The largest of these, a swarm near Calipatria, California, included an event of M 3.6 and 3.3. The other included an M 3.1 and was about 100 km to the west of the Calipatria swarm. The M 3.6 is the first of M>=3.6 within about 50 km of these epicenters since an M 3.6 on March 1, 2017. The last of larger magnitude was an M 4.0 on December 31, 2016. Forecast 109206 had expected this event within about 25 km of the epicenter was most likely around July 24. These epicenters are located at 102-103 degrees from the M 6.7 in the Dodecanese Islands of July 20. This is an area which was put under a seismic watch following that event in this summary as follows:

 

 

"The strongest earthquake in the U.S, Canada and Vicinity today was an M 3.9 in Baja California with an aftershock of M 3.0 one minute before the mainshock in Greece. This event occurred shortly before the event in Greece but may be related by distance as it is located at 102-103 degrees from the earthquake in Greece. Baja and Southern California as well as eastern Mexico are in this triggering distance range and should be carefully watched in the next week for signs of a larger impending earthquake. This is not impossible in mid-July as the Bakerfield earthquake 65 year ago today of July 21, 1952 of M 7.7-8.0  illustrates. The 22-year cycle in seismicity in Southern California peaking this year also has not seen an expected event yet." (July 20-21, 2017)

 

O: 26JUL2017 20:12:12  33.2N  115.6W ml=2.2  ANSS   WNW of Calipatria CA

O: 26JUL2017 20:03:33  33.2N  115.6W ml=2.2  ANSS   WNW of Calipatria CA

O: 26JUL2017 19:56:34  33.2N  115.6W ml=2.1  ANSS   WNW of Calipatria CA

O: 26JUL2017 19:53:20  33.2N  115.6W ml=2.1  ANSS   WNW of Calipatria CA

O: 26JUL2017 19:43:57  33.2N  115.6W mw=3.6  ANSS   13km WNW of Calipatria

O: 26JUL2017 19:12:14  33.2N  115.6W ML=2.1  EMSC   SOUTHERN CALIFORNIA          

O: 26JUL2017 19:53:20  33.2N  115.6W ML=2.1  EMSC   SOUTHERN CALIFORNIA          

O: 26JUL2017 20:03:33  33.2N  115.6W ML=2.2  EMSC   SOUTHERN CALIFORNIA          

O: 26JUL2017 20:12:12  33.2N  115.6W ML=2.2  EMSC   SOUTHERN CALIFORNIA          

O: 26JUL2017 19:03:36  33.2N  115.6W ML=2.7  EMSC   SOUTHERN CALIFORNIA          

O: 26JUL2017 19:08:42  33.2N  115.6W ML=3.3  EMSC   SOUTHERN CALIFORNIA          

O: 26JUL2017 19:56:34  33.2N  115.7W ML=2.1  EMSC   SOUTHERN CALIFORNIA          

O: 26JUL2017 19:43:57  33.2N  115.7W Mw=3.6  EMSC   SOUTHERN CALIFORNIA          

P: 24JUL2017 109206    32.9N  115.6W 2.5-4.6 AAAAA  So. California             

 

The westerly swarm included four event of M>=2 and an M 3.1. NEIC reported this earthquake of M 2.7 in Southern California was felt with intensity II-III in the area(s) of Aguanga, Anza and Idyllwild, California. This followed an M 3.1 earlier in the day felt in the same area. The last event within this region about 50 km from the epicenter of M>=3.1 was an M 3.5 a month ago on June 18, 2017. Earthquake of this type have been occurring about once a month during 2017. Forecast 108946 had expected this earthquake within about 10 km of the epicenter around July 21.

 

O: 26JUL2017 06:39:32  33.5N  116.8W ML=2.0  EMSC   SOUTHERN CALIFORNIA          

O: 26JUL2017 16:17:23  33.5N  116.8W ML=2.0  EMSC   SOUTHERN CALIFORNIA          

O: 26JUL2017 12:13:13  33.5N  116.8W ML=2.7  EMSC   SOUTHERN CALIFORNIA          

O: 26JUL2017 06:38:23  33.5N  116.8W ML=3.1  EMSC   SOUTHERN CALIFORNIA          

P: 21JUL2017 108946    33.4N  116.7W 2.5-4.4 BAAAA  So. California             

 

TROPICAL STORM NESAT SET TO INFLUENCE ASIAN SEISMIC PATTERN

 

EARTHQUAKE SUMMARY FOR JULY 25, 2017

 

 

A new Tropical Storm - TS Nesat -  formed today in the northwest Pacific Ocean with winds up to 055 kts. It is expected to track to the northwest reaching Taiwan around July 31. This storm is hitting the continental shelf off the northeastern Philippines at this time and motions induced from it could help promote seismicity further to the west in Taiwan and the Ryukyu Islands of Japan and perhaps later in Honshu. Seismicity in Honshu was slight elevated today with four moderate earthquakes of M 4-5 recorded in the region.

 

O: 25JUL2017 15:50:33  37.5N  141.5E mb=4.4  EMSC   NEAR EAST COAST OF HONSHU, JAP

P: 24JUL2017 109201    38.0N  142.0E 4.0-5.4 AAAAA  Off East Coast Honshu      

P: 25JUL2017 109201    37.0N  142.0E 4.0-5.6 AAAAA  Off East Coast Honshu      

 

NEIC reported this earthquake of M 4.4 off eastern Honshu, Japan was felt with intensity II-III in the area(s) of Sendai, Miyagi and Koriyama, Fukushima, Japan.

 

O: 25JUL2017 12:08:05  39.5N  141.9E Mw=4.5  EMSC   EASTERN HONSHU, JAPAN        

P: 25JUL2017 109212    39.0N  143.0E 4.0-5.5 AAAAA  So. of Honshu              

 

NEIC reported this earthquake of M 4.5 off northern Honshu, Japan  was felt with intensity II-III in the area(s) of Hachinohe, Aomori, Japan.

 

O: 26JUL2017 00:37:20  40.2N  143.3E mb=4.3  EMSC   OFF EAST COAST OF HONSHU, JAPA

P: 23JUL2017 109232    41.0N  143.0E 3.5-5.6 BAAAA  Hokkaido, Japan            

 

O: 25JUL2017 16:55:20  42.4N  145.6E mb=4.5  EMSC   HOKKAIDO, JAPAN REGION       

P: 23JUL2017 109232    41.0N  143.0E 3.5-5.6 ABBAA  Hokkaido, Japan            

 

An earthqake of M 4.9 in the western Visayas of the Philippines may also have

been promoted from TS Nesat.  NEIC reported this earthquake of M 4.9 in the Philippines was felt with intensity II-III in the area(s) of Nabitasan, Western Visayas, Philippines. PHIVOLCS reported this earthquake was felt with intensity IV in Anini-y and Tobias Fornier, Antique and II in Bacolod City; Iloilo City and La Paz, Iloilo City, Philippines. The last earthquake within about 150 km of this epicenter with M>=4.9 was an M 5.4 on August 15, 2016. The last nearer event at this magnitude or higher was an M 5.5 on June 9, 2014. 

Forecast 109140 had expected this event with was likely around July 29.

 

O: 25JUL2017 19:51:44  10.2N  122.1E mb=4.9  EMSC   PANAY, PHILIPPINES           

O: 25JUL2017 19:52:00  10.1N  122.0E MS=5.0  PHI  Felt with intensity IV

P: 29JUL2017 109140    12.0N  121.0E 3.5-5.2 BBAAA  Luzon, Philippines         

 

The strongest earthquake in the world today was an M 5.5 southwest of Sumatra, Indonesia. It was not initially reported felt and was followed by moderate aftershocks  of M 4.5 and 4.9. The last earthquake of M>=5.5 in this region was an M 5.5 on March 7, 2017 about 50 km southeast of today's epicenter. Forecast 109121 had expected this event within about 100 km of the epicenter, likely around July 28. Today's event follows a near-antipodal M 5.0 in Colombia two days ago. Antipodal pairs in these two regions are common especially at times of high geomagnetic activity. 

 

O: 25JUL2017 23:23:24   5.6S  101.5E Mw=5.5  EMSC   SOUTHWEST OF SUMATRA, INDONESI

O: 25JUL2017 23:57:49   5.7S  101.4E mb=4.9  EMSC   SOUTHWEST OF SUMATRA, INDONESI

O: 26JUL2017 00:21:50   5.8S  101.3E mb=4.5  EMSC   SOUTHWEST OF SUMATRA, INDONESI

P: 28JUL2017 109121     5.0S  102.0E 4.0-5.6 BAAAA  So. of Sumatera            

 

The most widely felt earthquake in the U.S. or Canada today occurred near Seattle and Tacoma, Washington. NEIC reported this earthquake of M 2.7 in Washington State was felt with intensity II-III in the area(s) of Bremerton, Port Orchard, Bainbridge Island, Seattle, Indianola, Poulsbo, Kingston, Port Ludlow, Freeland and Marysville, Washington. A series of earthquakes hit the area around May 10-11, 2017 with maximum magnitude M 3.5-3.6. Today's event appears to be an aftershock of those events. Forecast 109259 had expected this event was likely at the end of July.

 

O: 25JUL2017 09:08:43  47.6N  122.6W ML=2.7  EMSC   SEATTLE-TACOMA AREA, WASHINGTO

P: 29JUL2017 109259    47.5N  121.8W 2.0-3.9 BAAAA  Washington state, U.S.     

 

Southern California also continued in an active mode today. This may be partially due to its distance - about 103 degrees from the M 6.7 in the Dodecanese Islands of July 20. Seismic energy is concentrated at this distance and can help promote additional seismicity in this distance zone. Among regional earthquakes at this distance from Greece was a strong swarm in the Gulf of California which continued today at lesser magnitudes.

 

O: 25JUL2017 11:28:57  32.4N  115.5W ML=2.1  EMSC   BAJA CALIFORNIA, MEXICO      

P: 24JUL2017 109205    32.4N  115.8W 2.5-4.5 AAAAA  So. California             

 

O: 26JUL2017 01:53:52  33.2N  116.1W ML=2.7  EMSC   SOUTHERN CALIFORNIA          

P: 28JUL2017 109205    32.6N  116.1W 2.5-4.5 AAAAA  So. California             

 

NEIC reported this earthquake of M 2.7 in Southern California was felt with intensity II-III in the area(s) of Borrego Springs, California.

 

O: 26JUL2017 06:39:32  33.5N  116.8W ML=2.0  EMSC   SOUTHERN CALIFORNIA          

O: 26JUL2017 06:38:23  33.5N  116.8W ML=3.1  EMSC   SOUTHERN CALIFORNIA          

P: 21JUL2017 108946    33.4N  116.7W 2.5-4.4 BAAAA  So. California             

 

NEIC reported this earthquake of M 3.1 in California was felt with intensity II-III in the area(s) of Aguanga, Anza, Temecula, Valley Center, Vista, La Quinta, San Diego and Spring Valley, California.

 

 

NEW ZEALAND REGION ACTIVE NORTH TO SOUTH

 

EARTHQUAKE SUMMARY FOR JULY 24, 2017

 

On an otherwise uneventful day in global seismicity, the region os New Zealand saw a series of earthquakes stretching about every 500 km north in the Kermadec Islands to the Balleny Islands on the south. The strongest of these was an M 5.0 in the Balleny Islands. The others were M 4.7-4.9 with an M 4.4 in North Island north of Wellington. Forecasts 109335, 109074, 109337 and 109339 had expected these events in late July within about 100 km each.

 

O: 25JUL2017 07:13:28  34.5S  178.8W mb=4.8  EMSC   SOUTH OF KERMADEC ISLANDS    

P: 26JUL2017 109335    34.0S  180.0W 4.0-5.4 AAAAA  So. Kermadec Islands       

 

O: 24JUL2017 15:04:39  35.7S  178.6E mb=4.9  EMSC   OFF E. COAST OF N. ISLAND, N.Z

P: 21JUL2017 109076    35.0S  179.0E 3.0-4.4 BAAAA  North Island, N.Z.         

 

O: 24JUL2017 22:34:46  40.3S  176.8E MS=4.4  GEONET Felt with weak to light intensity

P: 26JUL2017 109337    40.0S  175.0E 3.0-4.6 AAAAA  North Island, N.Z.          

 

GEONET reported this earthquake was felt with weak to light intensity in the area of Central North Island, New Zealand. 6 felt reports were published including 4 of weak and 2 of light shaking.

 

O: 24JUL2017 16:20:48  44.5S  167.5E ML=4.7  EMSC   SOUTH ISLAND OF NEW ZEALAND  

O: 24JUL2017 16:20:46  44.4S  167.2E MS=4.8  GEONET Felt with weak to light intensity

P: 22JUL2017 109339    44.0S  168.0E 3.0-5.0 AAAAA  So. Island, N.Z.           

 

GEONET reported this earthquake was felt with weak to light intensity in the area of Southern South Island, New Zealand. 96 felt reports were published including 48 of weak and 44 of light shaking and 4 of moderate intensity.

 

O: 24JUL2017 15:50:12  61.6S  160.8E mb=5.0  EMSC   BALLENY ISLANDS REGION       

 

An unusual earthquake of M 5.0 also hit the Southern Mid-Atlantic Ridge today. This is in the antipodal area of the M 7.7 in the Komandorsky Islands of July 20 and may have been promoted by energy from that event. It is also near the antipode of TS Kulap in the northwest Pacific with possible promotion from antipodal energy concentrations from that storm as noted in previous summaries:

 

"TS Kulap continued today in the northwest Pacific Ocean with winds up to 045 kts. It is expected to track east of TD Noru to the west reaching the Volcano Islands of southern Japan around July 27. If it is still a storm at that time a regional seismic watch from the Volcano and Bonin Islands may be called. The antipode in the south Atlantic at 33S 15W is not a seismic zone but lies near the Southern mid-Atlantic Ridge. A moderate earthquake was recorded on this section of the Southern mid-Atlantic today and may have been promoted by antipodal effects of this storm." (July 24, 2017)

 

This is the strongest earthquake within about 250 km of this epicenter since an M 5.0 on November 15, 2016. The last of larger magnitude was an M 5.6 on June 13, 2014. Forecast 109087 had expected this segment of the Mid-Atlantic Ridge would like be active around July 21.

 

O: 24JUL2017 18:33:49  47.3S   11.9W mb=5.0  EMSC   SOUTHERN MID-ATLANTIC RIDGE  

P: 21JUL2017 109087    44.0S   16.0W 4.0-5.4 CCAAA  So. Mid-Atlantic Ridge     

 

The most unusual earthquake in the U.S. or Canada today occurred in northern Alaska with M 3.1. It was not reported felt in this remote epicentral zone but Only two other earthquakes have been recorded north of 70 degrees latitude in this area of Alaska in the past 25 years  - an M 4.4 on December 24, 2005 and an M 4.1 on November 6, 1999 both far to the west of today's epicenter. The strongest quake of the day was an unremarkable event in Southern Alaska of M 3.6, forecast within about 100 km to occur around July 24 in forecast 109288.

 

O: 24JUL2017 09:11:09  70.1N  143.6W ML=3.1  EMSC   NORTHERN ALASKA              

 

O: 24JUL2017 21:26:42  59.7N  152.5W ML=3.6  EMSC   SOUTHERN ALASKA              

P: 24JUL2017 109288    60.1N  150.6W 3.2-5.1 AAAAA  Central Alaska             

 

The strongest activity in North America continued to be shocks in the Gulf of California swarm which continued today at lower magnitudes than yesterday. These events are being recorded but not felt in the area. Forecast 108897 had expected this activity was likely around July 19.

 

O: 24JUL2017 05:04:37  24.8N  109.0W ML=4.0  EMSC   GULF OF CALIFORNIA           

O: 24JUL2017 05:04:37  24.7N  109.0W ML=4.0  UNAM  al SUROESTE de GUASAVE, SIN *: 24.

P: 19JUL2017 108897    24.0N  109.0W 3.5-4.9 BAAAA  Gulf of California         

 

 

STRONG SWARM HITS GULF OF CALIFORNIA

 

EARTHQUAKE SUMMARY FOR JULY 23, 2017

 

A notable swarm of earthquake with at least seven of M>=4 and maximizing with an M 4.5 hit the Gulf of California today. This activity was not unexpected at  this time as these events lie 104-105 degrees from the epicenter of the M 6.7 in Greece of July 20, 2017 and from the New Zealand event of July 11 of M 6.8. This summary had emphasized this on July 21 as follows:

 

"The strongest earthquake in the U.S, Canada and Vicinity today was an M 3.9 in Baja California with an aftershock of M 3.0 one minute before the mainshock in Greece. This event occurred shortly before the event in Greece but may be related by distance as it is located at 102-103 degrees from the earthquake in Greece. Baja and Southern California as well as eastern Mexico are in this triggering distance range and should be carefully watched in the next week for signs of a larger impending earthquake. This is not impossible in mid-July as the Bakerfield earthquake 65 year ago today of July 21, 1952 of M 7.7-8.0 illustrates. The 22-year cycle in seismicity in Southern California peaking this year also has not seen an expected event yet." (July 21, 2017)

 

Today's earthquakes were not reported felt in this remote epicentral area. Recent Tropical Storm activity south and west of Mexico may have helped promote today's events, but thus far these storms have tracked into the Pacific. Later in the season they will begin to turn north and make landfall in Baja or in the Gulf of California.

 

The only earthquake of significantly larger magnitude in the Gulf of California during 2017 has been an M 5.2 on March 29 about 150 km northwest of today's epicenters. Forecasts 108897 had expected today's activity was likely around July 19 within about 100 km of these epicenters.

 

O: 04JUL2017 01:37:52  24.8N  109.3W ML=4.0  UNAM  al SUROESTE de LOS MOCHIS, SIN *:

O: 04JUL2017 01:56:46  24.8N  109.3W ML=4.0  UNAM  al SUROESTE de LOS MOCHIS, SIN *:

O: 04JUL2017 01:36:16  24.8N  109.3W ML=4.1  UNAM  al SUROESTE de LOS MOCHIS, SIN *:

O: 04JUL2017 01:43:45  24.8N  109.3W ML=4.5  UNAM  al SUROESTE de LOS MOCHIS, SIN *:

O: 04JUL2017 04:02:52  25.2N  109.8W ML=4.0  UNAM  al SUROESTE de AHOME, SIN *: 25.25

O: 04JUL2017 01:48:45  25.2N  109.8W ML=4.1  UNAM  l SUROESTE de AHOME, SIN *: 25.25°

O: 04JUL2017 03:14:07  25.3N  109.8W ML=4.2  UNAM  l SUROESTE de AHOME, SIN *: 25.38°

O: 24JUL2017 01:37:52  24.9N  109.4W ML=4.0  EMSC   GULF OF CALIFORNIA           

O: 24JUL2017 01:56:46  24.9N  109.4W ML=4.0  EMSC   GULF OF CALIFORNIA           

O: 24JUL2017 00:54:57  24.9N  109.4W ML=4.1  EMSC   GULF OF CALIFORNIA           

O: 24JUL2017 00:42:32  24.9N  109.4W ML=4.2  EMSC   GULF OF CALIFORNIA           

O: 24JUL2017 00:27:20  24.9N  109.4W ML=4.4  EMSC   GULF OF CALIFORNIA           

O: 24JUL2017 01:43:43  25.0N  109.6W mb=4.3  EMSC   GULF OF CALIFORNIA           

O: 24JUL2017 03:14:04  25.2N  109.7W mb=4.2  EMSC   GULF OF CALIFORNIA           

O: 24JUL2017 01:36:12  25.2N  109.8W mb=4.2  EMSC   GULF OF CALIFORNIA           

O: 24JUL2017 04:02:52  25.3N  109.8W ML=4.0  EMSC   GULF OF CALIFORNIA           

P: 19JUL2017 108897    24.0N  109.0W 3.5-4.9 BBAAA  Gulf of California         

 

 

The strongest earthquake in the world today was an M 5.6 in Northern Honshu, Japan. NEIC reported it was felt with intensity II-III in Misawa, Aomori and Sendai, Miyagi, Japan. This is the largest earthquake off northern Honshu, Japan during the year 2017. Earthquakes of M 5.1 hit south of this on July 6 and M 4.9 on May 20, 2017. The last event within about 150 km of this epicenter occurred on August 20, 2016 with M 6.0.  Forecasts 109232 and 109231 had expected this event was likely around July 23-28. This event is at 103 degrees from the strong June earthquakes in Guatemala and may have been promoted by energy from those events of M 6.8.

 

O: 23JUL2017 15:35:45  40.1N  143.2E Mw=5.6  EMSC   OFF EAST COAST OF HONSHU, JAPA

P: 23JUL2017 109232    41.0N  143.0E 3.5-5.6 AAAAA  Hokkaido, Japan            

P: 28JUL2017 109231    40.0N  142.0E 3.5-5.8 BAAAA  Hokkaido, Japan            

 

The strongest earthquake within the U.S. or Canada today was an M 4.0 in Southern Alaska. NEIC reported it was felt with intensity IV in Matanuska-Sustina Border, Alaska and II-III in Talkeetna, Wasilla and Anchorage, Alaska.

The last event within about 100 km of this epicenter with M>=4 was an M 4.1 on April 26, 2017. Forecast 109290 had expected this activity around July 23.

 

O: 24JUL2017 04:07:55  62.1N  150.2W ML=4.0  EMSC   CENTRAL ALASKA                

O: 24JUL2017 04:07:55  62.1N  150.2W ml=4.0  ANSS   WSW of Y Alaska

P: 23JUL2017 109290    62.9N  150.2W 3.2-5.3 AAAAA  Central Alaska             

 

AFTERSHOCKS CONTINUE IN GREECE AND TURKEY

 

EARTHQUAKE SUMMARY FOR JULY 22, 2017

 

A pair of aftershocks of M 4.6 and 4.7 in the Dodecanese Islands of Greece were widely felt today. These events follow the M 6.7 at this epicenter of July 20 which did considerable damage in the area, injured more than 500 and killed at least two people. Today's strongest aftershocks were reported by NEIC to have been felt with intensity IV in Pilion, Kardamaina and Kos, Dodecanese Islands and II-III in Kefalos and Antimakhia, Greece as well as with intensity III in Bodrum and Marmaris, Mugla, Turkey up to 150 km from the epicenter. Forecasts 108908 and 109171 had expected this, and other activity in the area, in the period July 18-28 within about 100 km of these epicenters. An earthquake of M 4.3 also occurred in western Turkey today. This epicenter is not far from Istanbul where a large upcoming event is being prepared for. The occurrence of this M 4.3 days after the M 6.7 in the Dodecanese Islands suggests stresses are close to the breaking point in western Turkey at a number of sites. This could lead to a propagating rupture on the Anatolian Fault system and a major earthquake. Both the series in the Dodecanese Islands and the new epicenter in Turkey area at 103 degrees from the M 6.8 events in Guatemala of June 14 and 22 and were probably promoted from that source.

 

O: 22JUL2017 17:25:46  36.6N   26.8E ML=4.7  EMSC   DODECANESE ISLANDS, GREECE   

P: 18JUL2017 108908    36.0N   26.0E 3.0-4.8 BAAAA  Aegean Sea                  

 

O: 22JUL2017 17:09:21  37.0N   27.4E ML=4.5  EMSC   DODECANESE IS.-TURKEY BORDER RE

P: 28JUL2017 109171    38.0N   26.0E 3.0-4.9 CAAAA  Aegean Sea                 

 

O: 22JUL2017 22:12:32  40.0N   27.2E ML=4.3  EMSC   WESTERN TURKEY               

P: 19JUL2017 108990    41.0N   27.0E 3.0-5.3 BAAAA  Romania/NW Turkey          

 

The most widely felt earthquake in the U.S. or Canada today was an M 2.7 in northern  Arkansas. It was reported felt with moderate intensity through about 100 km from the epicenter.  The only events in Arkansas this year of M>=2.6 occurred about 100 km northwest of today's epicenter on June 11 and 16 with M 3.6 and 2.8 and 200 km south of this on January 12, 2017. The last event within about 100 km of this epicenter of M>=2.8 occurred July 28, 2016 with M 2.8-2.9. Forecast 109194 had expected regional activity around July 25.

 

NEIC reported this earthquake of M 2.7 in Arkansas was felt with intensity IV in Timbo, Arkansas and II-III in the area(s) of Fox, Mountain View, Edgemont, Onia, Fairfield Bay, Shirley, Marcella, Leslie, Dennard, Calico Rock, Marshall, Saint Joe, Harrison, Benton, Arkansas.

 

O: 22JUL2017 22:23:33  35.8N   92.3W MD=2.6  EMSC   ARKANSAS                     

P: 25JUL2017 109194    36.3N   89.5W 2.0-4.0 BABAA  New Madrid area            

 

The largest earthquake in the U.S. or Canada today was an M 5.1 in the Near Islands, Alaska. This is an aftershock of the June 2 M 6.8 mainshock. The area was re-activated following the M 7.7 in the Komandorsky Islands of July 17 and a series of moderate aftershocks in the Near Islands have occurred in the past week. Forecast 109273 had expected this event within about 50 km of this epicenter was likely around July 27.  This event is at 103 degrees from the M 6.6 in  Southern New Zealand of July 11, 2017, a distance at which seismic promotion is likely following large earthquakes. An earthquake of M 4.3 in the northern Kuril Islands and an M 4.8 in Northeastern China shared this distance to New Zealand today.

 

O: 23JUL2017 04:10:03  53.7N  170.7E mb=5.1  EMSC   NEAR ISLANDS, ALEUTIAN ISLANDS

P: 27JUL2017 109273    54.0N  170.0E 4.0-5.9 BAAAA  Near Islands               

 

The most unusual earthquake of the day occurred in northeastern China with M 4.8. NEIC reported this earthquake of M 4.8 in Northeastern China was felt with intensity IV in Qianguo, Jilin, China and V in Fuyu and IV in Harbin Heilongjiang, China and II-III in the area(s) of Saertu, Changchun, Lanxi and Jilin. It was also felt with intensity II in Shenyang, Liaoning, China.

This is the strongest earthquake within about 200 km of this epicenter in northeastern China since an M 5.5 on November 22, 2013. That event was an aftershock of an M 5.4 on October 31, 2013, the strongest in teh area in the past 25 years. Events of M>=4.8 hit the area on July 25, 2005 (M 4.9) and December 20, 2009 (M 4.8). Forecast 108978 had expected this event was likely within about 50 km of this epicenter around July 20. This event is at 101 degrees from the M 6.6 in  Southern New Zealand of July 11, 2017, a distance at which seismic promotion is likely following large earthquakes. An earthquake of M 4.3 in the northern Kuril Islands and an M 5.1 in the Near Islands, Alaska shared this distance to New Zealand today.

 

 

O: 22JUL2017 23:13:36  45.2N  124.7E mb=4.8  EMSC   JILIN-HEILONGJIANG BDR, CHINA

P: 20JUL2017 108978    45.0N  124.0E 3.5-5.4 AAAAA  NE China                   

 

Unusually large activity in the Virgin Islands continued today following the M 4.7 yesterday north of this region. An M 4.2-4.3 was the largest event in  the region today. It may be related to the event north of the Virgin Islands yesterday as noted in this summary:

 

 

"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 subduction zone earthquakes and in some cases can be precursory." (July 22,, 2017)

 

No earthquakes have occurred within the Virgin Islands Region during the current year. The last of M>4.3 was an M 4.4 on  November 18, 2016.   Forecasts 109156 and 109138 had expected this activity was likely between July 22 and 26.

 

O: 23JUL2017 00:18:03  19.1N   64.8W mb=4.3  EMSC   VIRGIN ISLANDS REGION        

O: 23JUL2017 00:18:02  19.3N   64.7W md=4.2  ANSS   Town British Virgin Islands

O: 22JUL2017 16:18:20  19.7N   64.5W MD=3.2  EMSC   VIRGIN ISLANDS REGION        

P: 22JUL2017 109156    20.0N   66.0W 3.0-4.8 AAAAA  Bahamas/No. Caribbean      

P: 24JUL2017 109138    18.0N   64.0W 3.0-5.3 ABAAA  Leeward Islands            

P: 26JUL2017 109138    19.0N   65.0W 3.0-5.1 BAAAA  Leeward Islands            

 

MODERATE CHILE QUAKE SHOWS CONTINUING METEOROLOGIAL PROMOTION

 

EARTHQUAKE SUMMARY FOR JULY 21, 2017

 

Global seismicity was marked today by continuing aftershocks in Guatemala, the Dodecanese Islands of Greece and Turkey and in the Komandorsky Islands of Russia. Despite this continuing presence, the largest earthquake of the day was probably promoted by smaller effects from two moderate tropical storms currently hitting Vietnam and the Philippines/Taiwan region. This earthquake of M 5.3 occurred at the antipode in southern Chile from TD 08W as expected in previous issues of this summary as:

 

"TD 08W continued today east of Vietnam with winds up to 040 kts. It is expected track to the west dissipating over the next several days. It could help promote seismicity in southern Asia in the meantime. The antipode is at 18S 68W, an area of southern Peru, Bolivia and northern Chile which saw a strong earthquake three days ago and could see additional promoted seismicity in the next several days. An M 5.3 occurred in northern Chile on July 19 and was felt with intensity IV." (July 20, 2017)

 

Forecast 109319 had expected this event within about 25 km of this epicenter

was likely around July 24.

 

O: 22JUL2017 06:29:50  21.2S   69.2W Mw=5.3  EMSC   TARAPACA, CHILE               

P: 24JUL2017 109319    21.0S   69.0W 4.0-5.5 AAAAA  Coast No. Chile            

 

Moderate aftershocks up to M 5.0 in the Dodecanese Islands, Greece continued to be felt throughout the region today. Maximum intensity was reported by NEIC at Bodrum, Turkey and Kos, Greece but light to moderate shaking also afflicted the Dodecanese Islands at Pilion, Kardamaina, Antimakhia, Kefalos, Simi and Rodos and western Turkey at Milas, Marmaris, Soke, Aydin, Koycegiz, Fethiye. 

This activity had been anticipated at this time in forecast 108908 within about 100 km of these events.

 

A moderate M 4.5 in Crete, Greece also occurred today. NEIC reported it was felt in Greece with intensity II-III in Nea Anatoli, Ierapetra, Arkalokhorion, Aghios Nikolaos, and Iraklion among other localities within about 50 km of the epicenter. This is probably and aftershock of the M 5.3 which hit Crete on July 15 and is the largest aftershock in Crete to date of this event. Forecast 109171 had expected this event was likely within about 50 km of this epicenter around July 22.

 

Moderate regional activity also extended to central Italy today where and M 4.3 aftershock was widely felt. This is an aftershock of the M 5.7 which hit this epicenter on January 18, 2017. The only other aftershock to date of that event following January 18 with M>=4.3 occurred on February 3, 2017 with M 4.7. Forecast 108971 had expected today's event was likely in Italy within about 50 km of this epicenter around July 19.

 

NEIC reported this earthquake of M 4.3 in Central Italy was felt with intensity II-III in the area(s) of Abruzzen and Marken, Italy at Pietracamela, Teramo, Penna San Giovanni, Mogliano and Numana and in general within about 100 km of the epicenter.

 

 

O: 22JUL2017 02:13:07  42.6N   13.4E mb=4.3  EMSC   CENTRAL ITALY                

P: 19JUL2017 108971    43.0N   13.0E 3.0-5.2 AAAAA  Italy                      

 

O: 21JUL2017 10:36:53  34.8N   25.5E ML=4.3  EMSC   CRETE, GREECE                

P: 22JUL2017 109171    35.0N   26.0E 3.0-4.8 AAAAA  Aegean Sea                 

 

O: 21JUL2017 17:09:45  36.9N   27.3E mw=5.0  ANSS   NE of Kos Greece

O: 21JUL2017 17:09:49  36.9N   27.4E mb=4.6  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 21JUL2017 09:55:54  36.9N   27.7E ML=4.1  EMSC   ODECANESE IS.-TURKEY BORDER RE

P: 17JUL2017 108908    38.0N   26.0E 3.0-4.8 BBBAA  Aegean Sea                 

 

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. Forecast 1090156 had expected today's earthquake was likely within about 100 km of this epicenter around July 22.

 

O: 22JUL2017 09:41:04  20.1N   65.0W mb=4.7  EMSC   NORTH OF THE VIRGIN ISLANDS  

O: 22JUL2017 09:41:04  20.1N   65.0W mb=4.7  ANSS   Town British Virgin Islands

P: 22JUL2017 109156    20.0N   66.0W 3.0-4.8 AAAAA  Bahamas/No. Caribbean       

 

While Southern and Baja California continued to experience seismic effects  from the Dodecanese Islands earthquake of M 7.7. These areas lie at 103 degrees from that epicenter and could see moderate to strong seismic promotion in  coming days. The most widely felt earthquake in the U.S., however occurred in the New Madrid Fault zone of Tennessee.

 

NEIC reported this earthquake of M 2.7 in Baja California was felt with intensity II-III in the area(s) of Mexicali, Baja California.

 

O: 21JUL2017 21:53:24  32.2N  115.1W ML=2.7  EMSC   BAJA CALIFORNIA, MEXICO      

P: 24JUL2017 109205    32.4N  115.8W 2.5-4.5 BAAAA  So. California             

 

The earthquake in Tennessee was the first of M>=2.9 within about 100 km of

this epicenter since May 16, 2017 when an M 3.3 hit about 50 km northeast of today's epicenter. Forecast 109194 had expected this event within about 25 km of this epicenter was likely around July 25.

 

NEIC reported this earthquake of M 2.9 in Tennessee was felt with intensity II-III in the area(s) of Portageville, Missouri, Martin, Tennessee; Paducah, and La Grange, Kentucky and Brookland, Arkansas.

 

O: 21JUL2017 17:20:42  36.5N   89.6W mb=2.9  EMSC   SOUTHEASTERN MISSOURI        

O: 22JUL2017 06:39:57  36.5N   89.6W md=1.1  ANSS   SSW of Lilbourn Missouri

O: 21JUL2017 17:20:42  36.5N   89.6W md=2.9  ANSS   NW of Tiptonville Tennessee

P: 25JUL2017 109194    36.3N   89.5W 2.0-4.0 BAAAA  New Madrid area            

 

 

STRONG TIDAL QUAKE HITS DODECANESE ISLANDS, GREECE

 

EARTHQUAKE SUMMARY FOR JULY 20, 2017

 

A strong earthquake of M 6.7 hit the Greek Dodecanese Islands today. This was a tidally promoted event as it occurred within about 15 minutes of local solar midnight in an area where high tidal stresses and triggering were expected at this time as noted in the previous issue of this report:

 

 

"The new moon will arrive on July 23 at 09:46 UT. Longitudes which are sub-solar at this time center around 35 East longitude while those which are anti-solar are near 145 West longitude. These include the East African Rift, the middle east and eastern Europe in the east and Alaska in the west. Tidal triggering will enhance seismicity in these area but tidal triggering is not limited to these longitude and could occur in many tectonic regimes. Tidal enhancement of seismicity is most likely through July 26 and may combine with stresses from tropical storms and geomagnetic storms to trigger strong earthquakes." (July 19-20, 2017)

 

Geomagnetic effects from the strongest high latitude geomagnetic storm in more than a year were also prominent earthquake promoters at this time as noted in  previous issues of this report:

 

"This is the strongest storm since May 28 when AP reached 54 and the strongest at high latitudes since it reached AP of 117 on May 8, 2016 more than a year ago. Seismicity is expected to be high near the geomagnetic equator and at high latitudes over the next five days through July 23, some promoted by induced

electrical currents. A major earthquake is possible at the end of this period." (July 17-21, 2017)

 

 

The mainshock was reported by NEIC to have been felt with intensity up to VII within about 30 km of Bodrum, Mugla, Turkey and in the Dodecanese Islands, Greece at Kos and Ziparion. Intensity V-VI was felt in Datca, Turkey and Pilion Dodecanese Islands, Greece. Lesser shaking was reported from  the Dodecanese Islands at Kardamaina, Antimakhia, Kalimnos, Khorion, Panormos, Milas, Kefalos, Simi, Lakkion, and other areas within about 150 km of the epicenter. Minor damage occurred in the epicentral area. Aftershocks were generally felt with intensity II-III within about 100 km of their epicenters in the regions of Rodos and Falirakion, Dodecanese Islands, Greece. Larger aftershocks  were reported felt with intensity up to VII in Kos and V in Kardamaina with lesser shaking in the Dodecanese Islands at Pilion, Kefalos, Simi, Ialisos, Rodos, Falirakion and Mesana, Greece.

 

The region has been active for several years and has seen most recent swarms following mainshocks of M>=5.3 on February 7, 2017 and December 20, 2016 (mainshocks of M 5.4 each). The last foreshock to today's activity within about 150 km of the epicenter was an M 4.9 on May 17. Earthquakes of M 5.0 on May 27 and 28 and on April 21, 2017 were followed by extensive aftershocks sequences. Some of these were expected (in this summary) to be indicators of an upcoming strong regional event as noted in the April 22, 2017 issue:

 

"A pair of moderate earthquakes hit the region of northwestern Turkey today. They occurred at slightly different epicenters about an hour apart with the second of M 4.9 probably triggered by the first of M 5.0. The first of these of M 5.0 was reported by EMSC to have been felt with moderate intensity in Usak and Alasehir, Turkey and with intensity VI in Selendi, Manisa; V in Foca, Izmir; IV in Turgutlu and Izmir and II-III in Khios, Greece and in Turkey at Ayvalik, Kestel, Bursa, Aydin, Kutahya, Turkey. EMSC reported the second was felt moderately in Turkey at Kusadasi, Soke, Balikesir, Denizli, Canakkale, and Istanbul, Turkey and in Petra, Greece. The second of  these was reported by NEIC to have been felt with intensity IV in Turkey at Izmir, Menemen, and with intensity II-III in Manisa, Selcuk, Kusadasi, Ayvalik, Balikesir, and Sultanbeyli, Istanbul. These lie near the projected epicenter of a major upcoming quake in the Istanbul area and may be precursory to such a shortly expected event. As they are separated by nearly 100 km they may mark the ends of such a rupture.  They are the first events of M>=5 within about 100 km of this region since events of M 5.9 on May 19, 2011 in the east and of M 5.2 on April 17, 2003 in the west." (April 22, 2017) 

 

and on May 28:

 

"An earthquake of M 5.0 and aftershock of M 4.9 were also widely felt in the region south of Istanbul, Turkey on the Anatolian Fault zone. A large earthquake in this area is widely anticipated." (May 28, 2017)

 

The earthquakes of April 22 and 23 occurred on the 25th and 26th day of the lunar month, as did today's activity. This is two days before the new moon in  both cases and probably is a tidally driven earthquake promotion mechanism in the region. The last earthquake of M>=4.5 in the Dodecanese Islands of Greece was an M 4.9 on May 17, 2017.

 

The last earthquake within about 200 km of today's epicenters with M>=6.7 in

Greece occurred on January 8, 2006 about 300 km to the west of today's event. The last earthquake of M>6.7 within about 200 km of today's epicenter occurred on April 25, 1957, 60 years ago. As such this is a very important regional earthquake.   Forecasts 108908 and 108959 had expected today's activity was likely between July 17 and 21. These earthquakes 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. The second strongest  earthquake of the day - an M 5.5 in Vanuatu - was also at 103 degrees from  Guatemala. This summary discussed this relation in detail in the issue of June 23.

 

O: 21JUL2017 00:10:33  34.6N   25.7E ML=4.4  EMSC   CRETE, GREECE                

P: 22JUL2017 109171    35.0N   26.0E 3.0-4.8 AAAAA  Aegean Sea                 

 

O: 21JUL2017 00:33:52  36.8N   26.4E mb=4.3  EMSC   DODECANESE ISLANDS, GREECE   

O: 20JUL2017 22:50:45  36.8N   27.6E ML=4.0  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 21JUL2017 01:56:29  36.9N   27.4E ML=4.1  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 20JUL2017 22:31:11  36.9N   27.4E Mw=6.7  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 20JUL2017 22:31:12  36.9N   27.5E mw=6.7  ANSS   SSE of Bodrum Turkey

O: 21JUL2017 02:12:34  36.9N   27.4E mb=4.7  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 20JUL2017 22:37:38  36.9N   27.6E ML=4.1  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 21JUL2017 03:59:01  36.9N   27.6E ML=4.1  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 21JUL2017 05:14:00  36.9N   27.6E ML=4.2  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 21JUL2017 01:35:44  36.9N   27.6E ML=4.4  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 21JUL2017 01:38:49  36.9N   27.6E ML=4.6  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 20JUL2017 22:54:34  36.9N   27.6E Mw=4.5  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 21JUL2017 05:04:00  36.9N   27.6E Mw=4.6  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 21JUL2017 05:05:24  36.9N   27.7E Mw=4.6  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 21JUL2017 05:52:13  37.0N   27.3E ML=4.0  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 21JUL2017 01:50:30  37.0N   27.4E ML=4.0  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 21JUL2017 00:53:48  37.0N   27.4E ML=4.1  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 21JUL2017 01:25:34  37.0N   27.4E ML=4.1  EMSC   DODECANESE IS.-TURKEY BORDER R

O: 20JUL2017 22:53:00  37.0N   27.4E mb=4.6  EMSC   WESTERN TURKEY               

O: 20JUL2017 23:23:52  37.0N   27.4E mb=4.8  EMSC   DODECANESE IS.-TURKEY BORDER R

P: 18JUL2017 108908    36.0N   26.0E 3.0-4.8 AAAAA  Aegean Sea                 

P: 17JUL2017 108908    38.0N   26.0E 3.0-4.8 BAAAA  Aegean Sea                 

P: 21JUL2017 108959    39.0N   28.0E 3.5-4.9 ABAAA  Turkey                     

 

O: 20JUL2017 23:45:31  38.2N   26.3E mb=4.1  EMSC   NEAR THE COAST OF WESTERN TURK

P: 21JUL2017 108959    39.0N   28.0E 3.5-4.9 AABAA  Turkey                     

 

O: 20JUL2017 07:15:44  38.4N   21.9E ML=4.2  EMSC   GREECE                       

P: 19JUL2017 108933    39.0N   22.0E 3.0-4.7 AAAAA  No. Greece                 

 

 

The strongest earthquake in the U.S, Canada and Vicinity today was an M 3.9 in Baja California with an aftershock of M 3.0 one minute before the mainshock in Greece. This event occurred shortly before the event in Greece but may be related by distance as it is located at 102-103 degrees from the earthquake in Greece. Baja and Southern California as well as eastern Mexico are in this triggering distance range and should be carefully watched in the next week for signs of a larger impending earthquake. This is not impossible in mid-July as the Bakerfield earthquake 65 year ago today of July 21, 1952 of M 7.7-8.0  illustrates (see Earthquake History section of this report for further details on this earthquake). The 22-year cycle in seismicity in Southern California peaking this year also has not seen an expected event yet. NEIC reported it was felt with intensity II-III in Baja California at Maneadero and Tijuana and in Southern California at San Diego, Spring Valley, La Mesa, El Cajon, La Jolla, Santee, California. The last earthquake within about 100 km of this epicenter with M>=3.9 occurred on September 7, 2014 with M 4.0-4.2 and prior to that on February 23, 2013 (M 4.1). This is the strongest earthquake south of 32N latitude in the area since an M 4.9 on December 13, 2008 and may signal increased regional seismicity in this area to come. Forecast 109205 had expected regional activity at moderate levels around July 24.

 

O: 20JUL2017 22:30:13  31.8N  117.1W ML=3.1  EMSC   OFFSHORE BAJA CALIFORNIA, MEXI

O: 20JUL2017 22:30:13  31.8N  117.1W ml=3.1  ANSS   El Sauzal B.C. MX

O: 20JUL2017 21:05:51  31.8N  117.1W ml=2.8  ANSS   El Sauzal B.C. MX

O: 20JUL2017 21:05:51  31.9N  117.1W ML=2.8  EMSC   OFFSHORE BAJA CALIFORNIA, MEXI

O: 20JUL2017 19:42:21  31.9N  117.1W ML=3.9  EMSC   OFFSHORE BAJA CALIFORNIA, MEXI

P: 24JUL2017 109205    32.4N  115.8W 2.5-4.5 BAAAA  So. California             

 

 

SE

TROPICAL STORMS CONTINUE TO PROMOTE SEISMICITY

 

EARTHQUAKE SUMMARY FOR JULY 19, 2017

 

A series of earthquakes hit today in areas recently hit by major tropical storms or near their antipodes. The strongest of these events was an M 5.9-6.0 in the region of Mauritius and Reunion Island in the South Indian Ocean. This is antipodal to a series of hurricanes south of Mexico and was discussed extensively in the previous issue of this report. An M 5.8 also occurred off the coast of Honshu, Japan in an area previously visited by Typhoon Nanmadol earlier in July. An M 5.1 also occurred today in  the region of Barbados at an epicenter where the eye of Tropical Storm Don passed over in the past two days.

 

The earthquake in the South Indian Ocean near Mauritius and Reunion Islands of M 5.9-6.0 occurred near the antipode of a series of storms over the past week which have tracked south of Mexico. The possibility of such an antipodal earthquake had been discussed in this summary in the previous issue some of which  follows:

 

"A series of tropical storms south of Mexico is unlikely to promote much higher seismicity in that region as they are situated over the Pacific Plate, causing it to rise and increasing normal stress across the Mexican-Pacific subduction zone. This should lead to a reduction of regional seismicity. Microseisms, however concentrating by geometry at the antipode could lead to a substantial increase in activity in the Indian Ocean near Mauritius and Reunion Island on the Indian mid-Ocean Ridge. This has been a consistent theme in this summary over the years. In particular, on July 14 it was noted in regard to Hurricane Fernanda:" (July 18-19, 2017)

 

"Hurricane Fernanda continued today south of western Mexico with winds up to 90 kts. It is expected to track to the west over the next week far from land. No seismic watch is expected with this storm. The antipode at 11S 66E is in the South Indian Ridge where a promoted earthquake is possible." (July 14, 2017)

 

This is the strongest earthquake in the region of Mauritius or Reunion since an  M 6.7 on July 26, 2012 and prior to that an M 6.3 on August 16, 2010. The event in 2012 was the largest in the region within about 300 km of this epicenter in the past 25 years.  Forecast 109049 had expected this event was likely around July 17 within about 50 km of this epicenter.

 

 

O: 19JUL2017 12:16:25  17.5S   66.7E Mw=5.9  EMSC   MAURITIUS - REUNION REGION   

P: 17JUL2017 109049    17.0S   67.0E 4.0-5.4 AAAAA  So. Indian Ocean           

 

A moderately strong earthquake also occurred today off the east coast of Honshu, Japan with M 5.8. NEIC reported maximum intensity IV in Hitachi, Ibaraki and in Koriyama, Fukushima, Japan. Intensity II-III was reported from Sendai, Miyagi in Ibaraki at Mito, Minori, Kashima, Tsuchiura, Naka, Ishige; in Tochigi at Oyama, Utsunomiya; in Chiba at Narita, Tomisato, Kashiwa, Narashino, Chiba, Ichikawa; in Gunma at Ora, Ota; in Saitama at Misato, Soka, Ageo, Warabi, Kawaguchi, Saitama, Toda, Kawagoe, Wako, in Tokyo at Tokyo, Mitaka, Komai; in Kanagawa at Kawasaki, Yokohama,  Yokosuka, Fujisawa, Samukawa and as far as Shizuoka and Akita, Japan up to 300 km from the epicenter. TS Nanmadol passed over this epicenter earlier this month and may have helped promote today's event as noted at the time:

 

"TS    NANMADOL 2017-07-05  00:00 UT  34.8N  142.4E  040 kts  SE Honshu, Japan                

 

Tropical Storm Nanmadol (05W) passed over Tokyo, Japan with winds up to 40 kts today. It is expected to dissipate over the next day.  While this is not a strong storm the location of the eye could reduce normal friction along the Japanese subduction zone making a strong earthquake in the area likely at this time. This is the first storm of the new typhoon season, and while not large, it  could have seismic triggering potential for the area. Japan is under a seismic watch through July 7. A moderate to strong quake may occur in the  subduction zone of eastern or southern Japan during this period." (July 7, 2017)

 

This is the strongest earthquake off the coast of Honshu, Japan since a similar M 5.8 on February 28, 2017 within 25 km of this epicenter. The last earthquake within about 200 km of this epicenter with M>=5.8 occurred on December 28, 2016 with M 5.9. A strong M 6.9 hit the region on November 21, 2016.  Forecast 108940 had expected today's event within about 50 km of the epicenter around July 19.

 

O: 20JUL2017 00:11:26  37.4N  141.5E Mw=5.8  EMSC   NEAR EAST COAST OF HONSHU, JAP

O: 20JUL2017 00:56:50  37.4N  141.6E mb=4.3  EMSC   NEAR EAST COAST OF HONSHU, JAP

P: 19JUL2017 108940    38.0N  142.0E 4.0-5.5 AAAAA  Off East Coast Honshu      

 

An earthquake of M 5.1 in the Barbados region of the Caribbean today was felt

with intensity II-III in Bridgetown, Saint Michael, Barbados and in Couva, Trindad and Tobago. Tropical Storm Don passed over this epicenter over the past two days ago and probably helped trigger today's event as was expected in previous issues of this report:

 

"TS    DON      2017-07-18  00:00 UT  11.5N   55.4W  045 kts  NE of Venezuela      

 

TS DON formed today northeast of Venezuela with winds up to 045 kts. It is expected to track to the west north of Venezuela and Colombia over the next four days. Seismicity may increase in the region of Venezuela and Colombia as this storm passes by." (July 18, 2017)

 

The last earthquake in the Barbados region within about 200 km of this epicenter occurred on April 20, 2016 with M 5.8 and prior to that an M 5.0 on October 28, 2015. Forecast 108893 had expected this event about 300 km to the west was likely around July 16. This epicenter is located at 102-103 degrees from the M 7.7 in the Komandorsky Islands. Strong seismic energy returns to the surface at this distance from major earthquakes and can help trigger additional seismicity.

 

O: 19JUL2017 13:31:36  12.3N   58.6W Mw=4.8  EMSC   BARBADOS REGION, WINDWARD ISL.

P: 16JUL2017 108893    11.0N   62.0W 3.4-5.1 BBCAA  Windward Islands           

 

The strongest activity in the U.S. or Canada today continued in the Near Islands, Aleutians as part of the aftershock sequence of the June 2 M 6.8 event there, re-energized by the Komandorsky M 7.7 of July 17 just to the west. The Near Islands are remote and these events are not being felt in that region. Earthquakes of M 4.6 and 4.9 were recorded in the Near Islands today. Forecast 109009 had expected this activity within about 50 km of these epicenter was likely around July 18.

 

O: 20JUL2017 06:49:44  53.6N  170.2E mb=4.6  EMSC   NEAR ISLANDS, ALEUTIAN ISLANDS

O: 20JUL2017 04:24:45  53.6N  171.4E mb=4.9  EMSC   NEAR ISLANDS, ALEUTIAN ISLANDS

P: 18JUL2017 109009    53.0N  171.0E 4.0-5.8 AAAAA  Near Islands               

 

ISMIC PROMOTION FROM KOMANDORSKY IS; TROPICAL STORMS LINGERS

 

EARTHQUAKE SUMMARY FOR JULY 18, 2017

 

A series of tropical storms south of Mexico is unlikely to promote much higher seismicity in that region as they are situated over the Pacific Plate, causing it to rise and increasing normal stress across the Mexican-Pacific subduction zone. This should lead to a reduction of regional seismicity. Microseisms, however concentrating by geometry at the antipode could lead to a substantial increase in activity in the Indian Ocean near Mauritius and Reunion Island on the Indian mid-Ocean Ridge. This has been a consistent theme in this summary over the years. In particular, on July 14 it was noted in regard to Hurricane Fernanda:

 

"Hurricane Fernanda continued today south of western Mexico with winds up to 90 kts. It is expected to track to the west over the next week far from land. No seismic watch is expected with this storm. The antipode at 11S 66E is in the South Indian Ridge where a promoted earthquake is possible." (July 14, 2017)

 

With additional storm (Greg and 08E) taking the Fernanda path this summary is anticipating addition seismic danger in the South Indian Ocean as:

 

 

"TROPICAL DEPRESSION 08E 

 

----  -------  ----------  --------  -----  ------  -------  ---------------

TD    08E      2917-07-19  00:00 UT  14.9N  119.7W  040 kts  South of W. Mexico      

 

TD 08E formed today south of Mexico with winds up to 040 kts. It is expected to

It is expected to track south of North America into the Pacific. No seismic watch is expected with this storm.. The antipode is at 15S 60E, an area of the South Indian Ocean where combined effects of Greg, Fernanda and 08E could help trigger a moderate to strong earthquake or Volcanic episode on Reunion Island in the next four days

 

TROPICAL STORM GREG (07E) 

 

----  -------  ----------  --------  -----  ------  -------  ---------------

TS    GREG     2017-07-19  00:00 UT  14.6N  109.6W  055 kts  South of W. Mexico      

 

TS Greg (TD 07E) continued today south of Mexico with winds up to 055 kts. It is expected to track to the west over the next week into the Pacific and not to encounter land. No seismic watch is expected with this storm. The antipode is at 15S 70E, an area of the South Indian Ocean where combined effects of Greg, Fernanda and 07E could help trigger a moderate to strong earthquake in the next four days." (July 18-19, 2017)

 

This region in the South Indian Ocean is also near the 103 degree distance from the Komandorsky Islands where an M 7.7 yesterday could help promote regional seismicity. It is also near the geomagnetic equator and could see seismic enhancement effects from the recent geomagnetic storm.

 

Otherwise, the strongest seismicity in the world today continued in the aftershocks of the M 7.7 Komandorsky Islands event of July 17. The strongest of these was an M 5.3 but the sequence is far from over and another strong earthquake is likely in the area in coming days. Forecast 109009 had expected this activity in the Komandorsky Islands was likely around July 18.

 

O: 18JUL2017 05:51:30  53.0N  169.1E mb=4.4  EMSC   KOMANDORSKIYE OSTROVA REGION 

P: 18JUL2017 109009    53.0N  171.0E 4.0-5.8 AAAAA  Near Islands               

 

O: 18JUL2017 16:52:45  53.8N  169.2E mb=4.1  EMSC   KOMANDORSKIYE OSTROVA REGION  

O: 19JUL2017 02:01:19  53.8N  169.2E mb=4.4  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 19JUL2017 03:25:02  53.9N  169.8E mb=4.8  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 08:00:01  54.1N  169.0E mb=4.1  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 09:34:10  54.2N  169.2E mb=4.1  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 07:10:46  54.3N  169.0E mb=4.5  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 13:10:52  54.4N  169.0E mb=4.5  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 10:39:30  54.6N  168.8E mb=4.4  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 05:02:59  54.6N  168.8E mb=4.6  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 05:20:55  54.6N  169.3E mb=4.4  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 05:20:55  54.6N  169.3E mb=4.4  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 20:39:41  54.7N  168.0E mb=4.4  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 06:02:39  55.2N  167.1E mb=5.3  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 19:31:24  55.5N  166.8E mb=4.8  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 06:39:53  55.6N  166.5E mb=4.7  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 09:17:12  55.7N  166.4E mb=4.5  EMSC   KOMANDORSKIYE OSTROVA REGION 

P: 18JUL2017 109009    56.0N  166.0E 4.0-5.9 AAAAA  Komandorsky Isl            

 

Yellowstone National Park in Wyoming/Montana has seen a slowly diminishing swarm of earthquakes over the past three weeks. This followed a strong start to the swarm in June and early July. This appears to have been re-energized following the M 7.7 in the Komandorsky Islands. An M 3.6 earthquake occurred in the area today and was accompanied by lighter quakes of M 2.2, 2.5, 2.8 and 2.2 among others. The M 3.6 is the second strongest earthquake in the swarm following an M 4.3 on June 14 at the beginning of this activity. Yellowstone is located at 51 degrees from the Komandorsky Islands, a nodal (#7) distance at which seismicity may be enhanced following major earthquakes. Forecast 109001 had expected  light to moderate Yellowstone activity around July 20.

 

NEIC reported this earthquake of M 3.6 in West Yellowstone, Montana was felt with intensity IV in West Yellowstone and II-III in the area(s) of Yellowstone National Park, Wyoming, Livingston, Montana and Island Park, Idaho.

 

O: 18JUL2017 20:33:56  44.8N  111.0W ML=2.2  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 18JUL2017 16:19:55  44.8N  111.0W ML=2.5  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 18JUL2017 20:40:24  44.8N  111.0W ML=2.8  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 18JUL2017 20:31:10  44.8N  111.0W ML=3.6  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 18JUL2017 20:52:46  44.8N  111.1W ML=2.2  EMSC   YELLOWSTONE NAT. PARK, WYOMING

P: 20JUL2017 109001    44.8N  111.9W 2.0-3.9 AAAAA  Yellowstone/Wyoming        

 

The strongest earthquake in the U.S. or Canada outside the Komandorsky aftershock zone in Near Island, Alaska today was an M 4.0 in the Kenai Peninsula, Alaska. This earthquake had been anticipated in forecast 109024 to occur in mid-July. The only events of M>=4 on the Kenai Peninsula during 2017

occurred on July 7 (M 4.4); May 30 (M 5.5) and May 7 (M 5.2). Today's event is probably an aftershock of theses earlier earthquakes.

 

 

NEIC reported the earthquake of M 4.0 in Kenai Peninsula, Alaska was felt with intensity II-III in the area(s) of Soldotna, Kasilof, Sterling, Cooper Landing, Kenai, Homer and Eagle River, Alaska. NEIC reported the earthquake of M 3.3 in Southern Alaska was felt with intensity II-III in the area(s) of Soldotna, Kenai and Anchorage, Alaska.

 

O: 18JUL2017 23:42:39  60.2N  150.9W ML=4.0  EMSC   KENAI PENINSULA, ALASKA      

O: 18JUL2017 08:29:12  60.5N  152.2W ML=3.3  EMSC   SOUTHERN ALASKA              

P: 15JUL2017 109024    60.9N  151.1W 3.2-5.1 BAAAA  Central Alaska              

 

Moderate aftershocks up to M 5.1 continued today in the Near Islands, Aleutians, Alaska. Aftershocks of the M 6.8 in the Near Islands of June 2 had large dissipated until the M 7.7 in the Komandorsky Islands yesterday. The aftershock sequence, however regenerated following the Komandorsky event. Forecast 109009 had expected this activity was likely around July 18.

 

O: 18JUL2017 08:40:34  53.0N  171.6E mb=4.2  EMSC   NEAR ISLANDS, ALEUTIAN ISLANDS

O: 18JUL2017 20:18:38  53.3N  171.9E mb=5.1  EMSC   NEAR ISLANDS, ALEUTIAN ISLANDS

O: 18JUL2017 04:48:28  53.5N  171.1E mb=4.7  EMSC   NEAR ISLANDS, ALEUTIAN ISLANDS

P: 18JUL2017 109009    53.0N  171.0E 4.0-5.8 AAAAA  Near Islands               

 

The earthquake of M 4.6 in Puerto Rico yesterday was followed by an M 4.4 to the west in the Dominican Republic today revealing regional activation at this time. A strong earthquake is likely in the area, being well overdue and regional activations can be an important clue as to when this will occur. The last earthquake of larger magnitude in the Dominican Republic was an M 4.5 on June 22, 2017. The strongest event of the current year was an M 4.7 on April 3, 2017.

Forecast 108888 had expected this event within about 100 km of the epicenter around July 19.

 

NEIC reported these earthquakes of M 4.3 and 3.0 in the Dominican Republic were felt with intensity II-III in the area(s) of Otra Banda, La Altagracia, Dominican Republic.

 

O: 18JUL2017 07:14:04  18.0N   68.2W MD=3.0  EMSC   DOMINICAN REPUBLIC REGION    

O: 18JUL2017 07:09:43  18.1N   68.0W ML=4.4  EMSC   MONA PASSAGE, PUERTO RICO    

O: 18JUL2017 09:48:57  18.2N   68.2W MD=3.0  EMSC   MONA PASSAGE, DOMINICAN REPUBL

P: 19JUL2017 108888    19.0N   68.0W 3.4-4.9 AAAAA  Puerto Rico                

 

 

M

STRONG EARTHQUAKE IN PERU FOLLOWS MAJOR KOMANDORSKY EVENT

 

EARTHQUAKE SUMMARY FOR JULY 17, 2017

 

As anticipated in this summary, strong to major earthquakes rocked areas on the geomagnetic equator and at high latitudes. The strongest of these was an M 7.7 in the Komandorsky Islands or Russia east of Kamchatka. This is the strongest earthquake in the world in half a year - since an M 8.0 in New Britain on January 22, 2017. The only other earthquake of M>=7 during 2017 was an M 7.9 on January 3, 2017 in the Tonga/Fiji area. It was preceded earlier by an M 6.2 foreshock. An earthquake of M 6.4 in Southern Peru followed several hours after the M 7.7 coincidental with a strong C-class solar flare. This event was probably promoted  by the Komandorsky event as it lies at the third node (120 degrees) from that epicenter. It was probably also promoted by high tidal stresses as it occurred within about an hour of local solar midnight. It is located on the geomagnetic equator in Peru and the current geomagnetic storm likely triggered the earthquake at this time. This activity had been anticipated in the previous summary as:

 

 

"The geomagnetic field was at major storm conditions today.  The AP level was 41. High latitude geomagnetic field also saw major storm conditions with AP at 91.  Aurora were observed. This is the strongest storm since May 28 when AP reached 54 and the strongest at high latitudes since it reached AP of 117 on May 8, 2016 more than a year ago. Seismicity is expected to be high near the geomagnetic equator and at high latitudes over the next five days through July 23, some promoted by induced electrical currents. A major earthquake is possible at the end of this period." (July 16-17, 2017)

 

The M 7.7 in the Komandorsky Islands of Russia was reported by NEIC to have damaged areas of Nikolskoye, Kamchatka with intensity VIII shaking. A tsunami was generated and initial reports gave height of 10 cm at Shemya,  A strong earthquake occurred in the Near Islands, Aleutians on June 2, 2017 with M 6.8 and this may be an extension of a propagating stress to the west. The strongest

earthquake in the Komandorsky Island during 2017 had been an M 4.9 on March 3. Earthquakes in this area including Kamchatka often coincide with strong geomagnetic storms and triggering is highly likely in this high latitude zone. Earthquakes within about 500 km of this epicenter of M>=7 have occurred most recently on November 6, 1990 with M 7.1. No earthquake of M>=7.7 have occurred in this area in at least 25 years. The last recorded event of M>=7.5 in the region was an 8.8 on June 20, 1936. Other such quakes occurred December 17, 1929 (M 7.8); September 2, 1907 (M 7.7); June 29, 1898 (M 7.6); January 22, 1858 (M 7.5) and October 28, 1849 (M 7.5). With the exception of the event in 1936 with questionable magnitude, today's earthquake is among the strongest ever recorded in this region.  Forecast 109009 had expected today's active would be strong and within about 100 km of these epicenters.

 

The epicenters in the Komandorsky Islands today are located at 103-104 degrees from the last major global earthquake - the M 6.6 in the Auckland Islands of New Zealand which occurred on July 11, 2017. Seismic energy from strong shocks reflects and refracts off core-mantle boundaries and returns to the surface in concentrated form at this distance. This may help promote zonal seismicity at this distance, such as the events in the Komandorsky Islands today. Other areas experiencing enhanced seismicity at this distance from the Auckland Islands today included central California (M 3.1, 2.9); the Gulf of California (M 4.6); and the Near Islands, Aleutians (M 5, 5.1 ..).

 

O: 18JUL2017 00:51:20  54.3N  168.9E mb=4.4  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 17JUL2017 23:49:29  54.3N  169.3E mb=5.2  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 00:26:31  54.4N  168.9E mb=5.3  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 01:03:48  54.4N  169.0E mb=4.8  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 17JUL2017 23:34:14  54.5N  168.8E mw=7.7  ANSS   ESE of Nikol'skoye Russia

O: 17JUL2017 23:34:14  54.5N  168.9E Mw=7.7  EMSC   KOMANDORSKIYE OSTROVA REGION 

P: 18JUL2017 109009    53.0N  171.0E 4.0-5.8 ABAAA  Near Islands               

 

O: 17JUL2017 11:23:01  54.6N  168.7E mb=5.1  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 17JUL2017 11:05:09  54.7N  168.6E Mw=6.2  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 17JUL2017 13:19:42  54.7N  168.8E mb=4.5  EMSC   KOMANDORSKIYE OSTROVA REGION 

O: 18JUL2017 01:51:40  55.5N  166.6E mb=5.1  EMSC   KOMANDORSKIYE OSTROVA REGION 

P: 18JUL2017 109009    56.0N  166.0E 4.0-5.9 AAAAA  Komandorsky Isl            

 

A series of regional aftershocks hit the Near Islands in the minutes following the M 7.7 in the Komandorsky Islands and may mark the end of the rupture. This is also the location of the M 6.8 of June 2 in the Near Islands where stress was relieved in that event. Propagation of the rupture further east is unlikely because of this earlier event.

 

O: 17JUL2017 23:52:49  53.2N  171.9E mb=5.1  EMSC   NEAR ISLANDS, ALEUTIAN ISLANDS

O: 17JUL2017 23:57:48  53.4N  170.9E mb=5.2  EMSC   NEAR ISLANDS, ALEUTIAN ISLANDS

O: 18JUL2017 01:06:39  53.9N  170.2E mb=5.0  EMSC   NEAR ISLANDS, ALEUTIAN ISLANDS

P: 18JUL2017 109009    53.0N  171.0E 4.0-5.8 AAAAA  Near Islands               

 

 

The earthquake in Peru of M 6.4 was felt with minor damage and intensity VII in Camana, Arequipa and IV in Acari, Arequipa, Nazca, Tacna, Arica, Mala, Lima Provinces, Iquique, Tarma, Chosica, San Luis and Lima. A further promoting factor may have been microseisms from TS Talas. This had been noted in the previous summary as:

 

"TS Talas continued today east of Vietnam with winds up to 065 kts. It is expected to track to the west over the next two days, dissipating over Burma and Laos on July 17. Induced motions may help activate strike-slip faulting as far as Myanmar, India and Afghanistan in the next several days. The antipode is in northern Chile at 18S 75W, a region where a promoted seismic event is  possible. These regions are under a weather-induced seismic watch through July 20 with the potential for a strong earthquake in this time and areas." (July 16-17, 2017)

 

The last earthquake in Southern Peru of moderately large magnitude was an M 5.7 on June 24 about 150 km north of today's epicenter. The last of larger magnitude in the region of southern Peru or northern Chile within about 200 km of this epicenter occurred on September 25, 2013 about 100 km northwest of this and with M 7.6 on July 7, 2001 (M 7.6) an aftershock of an M 8.4 of June 23, 2001. That  event occurred in conjunction with a solar eclipse witnessed throughout the region which occurred on June 21, 2001 beginning in central Chile.   This summary argued at the time that this was not coincidental and that strong tidal stresses associated with the eclipse, as in the Izmit, Turkey event of August, 1999 helped time the occurrence of this event. Incidentally, a much anticipated solar eclipse will be visible across much of the United States a month from now on August 21, 2017. It is likely to promote seismicity from Oregon and California to southeastern U.S.  This summary will watch this event carefully. Forecast 109051 had expected today's event within about 50 km of this epicenter around July 14.

 

IGP reported the M 6.3 was felt with intensity V in Peru at  Atico; III-IV Arequipa, II-III Tacna, Moquiegua; II Ica, Peru. CSN reported it was felt with intensity III in Chile at  Arica, Cuya, Pocon Chile, Alto Hospicio, Huara, Iquique. Felt in Arica, Parinacota and Tarapaca, Chile. The M 4.5 aftershock was felt with intensity II-III in  Atico, Peru.

 

O: 18JUL2017 02:05:19  16.4S   73.7W Mw=6.4  EMSC   NEAR COAST OF SOUTHERN PERU  

O: 18JUL2017 02:05     16.6S   73.8W mb=6.3  IGP    Atico; III-IV Arequipa, II-III

O: 18JUL2017 02:05:19  16.4S   73.6W mw=6.4  ANSS   WNW of Camana Peru

O: 18JUL2017 02:05     16.9S   73.6W mb=6.3  GUC    Arica, Cuya, Pocon Chile, Alto

O: 18JUL2017 03:28     16.4S   74.0W mb=4.5  IGP    Atico, Peru.                 

P: 14JUL2017 109051    17.0S   74.0W 4.0-5.8 BAAAA  So. Peru/Bolivia           

 

An earthquake of M 3.1 south of San Francisco, California was widely felt today.

NEIC gave maximum intensity IV in Freedom, California with intensity II-III reported within about 125 km of the epicenter at Merced, San Francisco, Manteca, Los Altos, Sunnyvale, Santa Clara, Campbell, Santa Cruz, Monterey, Pacific Grove, San Jose, Marina, Morgan Hill, Castroville, Aptos, San Martin, Salinas, San Juan Bautista, Moss Landing, Gilroy, Aromas and Watsonville, California. A foreshock of M 2.9 was felt in the same area. This is the strongest earthquake within about 50 km of this epicenter since an M 3.5 on May 22, 2017. Forecast 108915 had expected this events within about 25 km of this epicenter was likely around July 18.

 

O: 17JUL2017 22:21:36  36.9N  121.7W ML=2.9  EMSC   NORTHERN CALIFORNIA          

O: 17JUL2017 22:32:07  36.9N  121.7W ML=3.1  EMSC   NORTHERN CALIFORNIA          

P: 18JUL2017 108915    37.1N  121.5W 2.5-4.6 AAAAA  Central California         

 

AJOR GEOMAGNETIC STORM MAY BRING FRESH SEISMICITY

 

EARTHQUAKE SUMMARY FOR JULY 16, 2017

 

The geomagnetic field was at major conditions today.  The AP level was 41. High latitude geomagnetic field also saw major storm conditions with AP at 91. Aurora were observed. This is the strongest storm since May 28 when AP reached 54 and the strongest at high latitudes since it reached AP of 117 on May 8, 2016 more than a year ago. Seismicity is expected to be high near the geomagnetic equator and at high latitudes over the next five days through July 23, some promoted by induced electrical currents. A major earthquake is possible at the end of this period. The strongest earthquakes of the day, a pair of events of M 5.4 and 5.6 on the geomagnetic equator in Tonga may have been the first of this activity.

 

The last earthquake within about 200 km of today's event in Tonga with M>=5.6 was an M 5.6 on November 16, 2016 and prior to that on January 25, 2016 both with M 5.6-5.7. The last regional event of significantly greater magnitude occurred on July 6, 2015 with M 5.8-6.2.  Forecast 109065 had expected today's earthquakes were likely within about 50 km of this epicenter around July 15.

 

O: 17JUL2017 01:20:46  20.4S  173.9W Mw=5.6  EMSC   TONGA                        

O: 17JUL2017 01:20:32  20.4S  173.3W mw=5.6  ANSS   ESE of Pangai Tonga

O: 16JUL2017 17:06:41  20.4S  173.5W mw=5.5  ANSS   SE of Pangai Tonga

O: 16JUL2017 17:06:47  20.4S  174.0W Mw=5.5  EMSC   TONGA                        

P: 15JUL2017 109065    20.0S  174.0W 4.0-5.6 AAAAA  Tonga Islands              

 

An earthquake of M 4.5 occurred in the Arctic Ocean as today's geomagnetic storm hit and may have been triggered by it. This event in the Svalbard region north of Norway was not reported felt. It is the strongest in the area since an M 5.0 on May 31, 2007 and may be an aftershock of that earthquake. Forecast 109039 had expected a moderate earthquake in this area around July 13.

 

O: 16JUL2017 04:49:22  77.0N   18.7E mb=4.5  EMSC   SVALBARD REGION               

O: 16JUL2017 04:49:24  77.0N   18.7E mb=4.5  ANSS   Svalbard and Jan Mayen

P: 13JUL2017 109039    74.0N   14.0E 3.0-4.6 BCAAA  Norway                     

 

A moderate earthquake of M 4.7 in Puerto Rico today topped the list of events in the U.S. or Possessions. NEIC reported this earthquake was felt with maximum intensity IV in Puerto Rico at Arecibo, Rincon, Bayamon, and with intensity II-III in  Aguas Buenas, San Juan, Guaynabo, Carolina, Toa Alta, Catano, Morovis, Dorado, Vega Baja and Hatillo.  This event at 64 West longitude, and the M 5.9 in Minahasa, Indonesia yesterday at 122 East longitude may have been promoted by today's geomagnetic storm and the high tidal stresses associated with the full moon which maximized near this longitude as previously reported in this summary:

 

"The full moon arrived at 04:07 UT on July 9, 2017. Longitudinal zones which were sub-solar at this time lie near 120 degrees East longitude and 60 degrees

west longitude and include area of Japan, the Philippines and Indonesia in the

east and the Caribbean and South America in the West." (July 7-13, 2017)

 

The mainshock of M 4.7 and an aftershock of M 4.4 four hours later were the strongest earthquake recorded in Puerto Rico during the year 2017 and the largest within about 200 km of these epicenters since an M 5.8 on May 28, 2014 - a regional aftershock of the M 6.4 of January 13, 2014. Forecast 108889 had expected  today's earthquake was likely around July 15 within about 100 km of the epicenter. No major damage was reported with today's earthquake.

 

NEIC reported this earthquake of M 4.1 in Puerto Rico was felt with intensity II-III in the area(s) of San German, Puerto Rico.

 

O: 17JUL2017 06:12:09  19.0N   66.8W mb=4.4  EMSC   PUERTO RICO REGION           

O: 17JUL2017 02:19:04  19.0N   66.9W mb=4.7  EMSC   PUERTO RICO REGION           

O: 17JUL2017 02:19:02  19.1N   66.8W md=4.7  ANSS   Hatillo Puerto Rico

O: 17JUL2017 02:38:09  19.1N   66.7W mb=4.0  EMSC   PUERTO RICO REGION           

O: 17JUL2017 05:15:09  19.1N   66.8W MD=3.4  EMSC   PUERTO RICO REGION           

O: 17JUL2017 03:29:08  19.1N   66.8W Md=3.0  EMSC   PUERTO RICO REGION           

P: 15JUL2017 108889    19.0N   66.0W 3.4-5.3 AAAAA  Puerto Rico                

 

An earthquake of M 4.6 in the Gulf of California today may have been promoted by the passage of the strong hurricane Fernanda to the southwest over the past several days. This summary, in past issues, had noted this possibility. The only earthquake of larger magnitude in the Gulf of California during 2017 was an M 5.2 at this same epicenter on March 29. Forecast 108897 had expected today's event around July 19.

 

O: 17JUL2017 05:25:22  25.8N  110.1W ML=4.6  EMSC   GULF OF CALIFORNIA           

O: 17JUL2017 05:25:22  25.7N  110.0W ML=4.6  UNAM  l OESTE de AHOME, SIN *: 25.78°, -

P: 19JUL2017 108897    24.0N  109.0W 3.5-4.9 ABAAA  Gulf of California         

 

The largest earthquake in California today was an M 3.5 near Boron, Central California. NEIC reported it was felt with intensity II-III in Edwards, Boron, Mojave, Littlerock, Los Angeles, California. The last earthquake within about 50 km of this epicenter in Southern California with M>=3.5 occurred on June 4, 2017 also with M 3.5, the last of larger magnitude in the area was an M 4.3 on December 27, 2015, following a pair of M 3.7 and 3.8 the day before.

Forecasts 108688 and 108949 had expected this event was likely between July 11 and 17.

 

O: 16JUL2017 13:27:49  35.0N  117.4W ML=3.5  EMSC   SOUTHERN CALIFORNIA          

P: 11JUL2017 108688    35.9N  117.7W 2.5-4.4 BAAAA  So. California             

P: 17JUL2017 108949    35.6N  118.4W 2.5-4.6 AAAAA  So. California             

 

The most unusual earthquake of the day was an M 4.9 near the geomagnetic equator in the South Pacific Ocean. This event is the first of this size within about 400 km of this epicenter in at least 25 years.

 

O: 16JUL2017 19:26:43   5.8S  122.8W mb=4.9  EMSC   SOUTH PACIFIC OCEAN          

 

 

MODERATE EARTHQUAKE SHAKES OKLAHOMA

 

EARTHQUAKE SUMMARY FOR JULY 14, 2017

 

The strongest earthquake in the U.S. or Canada today was an M 4.2 in the area of Stroud, Oklahoma. NEIC reported this event was felt with intensity IV in Stroud, Cushing, Drumright, Chandler, Yale, Jennings, Meeker, Stillwater, Luther, Pawnee, and in general within about 60 km of the epicenter. Intensity II-III was felt within about 200 km of the epicenter in Oklahoma, Kansas, Arkansas, Missouri, Texas, and possibly as far as 500 km away in Iowa, Colorado and Indiana. A strong aftershock sequence followed and many of these aftershocks were felt with intensity II-III in the area from Stroud to Stillwater within about 50 km of the epicenters. The only other event in Oklahoma during 2017 of M>=4.2 was an M 4.2 on May 13, 2017. The last event of larger magnitude occurred  on November 7, 2016 with M 5.0. This event occurred at the same epicenter as today's which may be considered an aftershock of the November earthquake. Forecast 108954 had expected today's earthquake was likely around July 12 with the full moon within about 50 km of today's epicenter. This epicenter at 120 degrees (node 3) from southern New Zealand may also have been promoted by the M 6.6 there on July 11.

 

O: 14JUL2017 14:03:30  35.9N   96.7W ML=2.7  EMSC   OKLAHOMA

O: 14JUL2017 14:04:50  35.9N   96.7W Mw=3.5  EMSC   OKLAHOMA

O: 14JUL2017 14:17:50  35.9N   96.7W Mw=3.7  EMSC   OKLAHOMA

O: 14JUL2017 13:47:35  35.9N   96.7W Mw=4.2  EMSC   OKLAHOMA

O: 14JUL2017 14:55:51  35.9N   96.7W mb=2.7  EMSC   OKLAHOMA

O: 14JUL2017 15:04:21  35.9N   96.7W mb=2.9  EMSC   OKLAHOMA

O: 14JUL2017 15:39:29  36.0N   97.9W mb=2.3  EMSC   OKLAHOMA

O: 14JUL2017 19:03:01  36.0N   97.9W mb=2.4  EMSC   OKLAHOMA

O: 14JUL2017 15:11:32  36.0N   97.9W mb=2.7  EMSC   OKLAHOMA

O: 14JUL2017 20:34:24  36.8N   97.6W mb=2.2  EMSC   OKLAHOMA                     

P: 12JUL2017 108954    36.0N   96.0W 2.0-4.1 AAAAA  Southern Plains            

 

The strongest earthquake in the world today was an M 5.3 in Central Chile. NEIC

reported it was felt with intensity V-VI in Vina del Mar, La Ligua, Quilpue, Valparaiso, Chile. Intensity II-IV was reported from Santiago, Concepcion, Bio Bio, Chile. CSN reported this earthquake was felt with intensity  IV in  San Antonio, III Valparaiso, Vina del Mar, Navidad, Felt in Valparaiso, Chile.

A foreshock of M 4.6 was felt with intensity IV in Valparaiso, Chile. The last earthquake within about 100 km of today's event was an M 5.9 on April 28, an aftershock of an M 6.9 which hit the area on April 24. Today's event occurred about 100 km southwest of that mainshock and may be a regional aftershock. Forecast 109071 had expected this event was likely around July 15.

This epicenter is at the seventh node (52 degrees) from the earthquakes of M 6.9 in Guatemala of June 14 and 22 and may have been promoted from that source.

 

O: 14JUL2017 12:00:29  33.7S   72.5W Mw=5.3  EMSC   OFFSHORE VALPARAISO, CHILE   

O: 14JUL2017 11:41:15  33.7S   72.6W mb=4.5  EMSC   OFFSHORE VALPARAISO, CHILE   

O: 14JUL2017 12:00     33.8S   72.5W mb=5.4  GUC    San Antonio, III Valparaiso, V

P: 15JUL2017 109071    33.0S   73.0W 4.0-5.8 AAAAA  Central Chile              

 

NORTHERN SUMATRA SHAKES

 

EARTHQUAKE SUMMARY FOR JULY 13, 2017

 

The largest earthquakes in the world today occurred along the Southwestern Pacific subduction zone and included an 5.0-5.5 in Sumatra, the largest of the day as well as events of M 5.1 in the Kermadec Islands and in Timor, Indonesia. The last earthquake within about 200 km of the event in Sumatra with M>=5.5 was an M 5.4 on January 6, 2017. The last event in the region with stronger magnitude occurred on September 1, 2016 with M 5.8 and prior to that on November 8, 2015 (M 6.1). 

 

BMG reported this earthquake was felt with intensity IV in Aekgodang and III in Padang Sidempuan, Sialang and Sipirok, Sumatra, Indonesia.

 

Forecast 108841 had expected today's epicenter would be active around July 15. Activity in Sumatra at this time had been thought likely following the M 6.4-6.6 south of New Zealand as noted in this summary at the time:

 

"Sumatra could see moderate to large triggering in the next several days." (July 11, 2017)

 

O: 14JUL2017 02:11:30   1.5N   99.2E ML=3.9  EMSC   NORTHERN SUMATRA, INDONESIA  

O: 14JUL2017 01:25:16  01.4N  099.2E MS=5.5  BMG  Felt with intensity IV

O: 14JUL2017 01:25:15   1.5N   99.3E mb=5.0  EMSC   NORTHERN SUMATRA, INDONESIA  

P: 15JUL2017 108841     0.0N   99.0E 4.0-5.4 ABAAA  So. Sumatera               

 

The strongest earthquakes in the U.S. or Canada today were a pair of events of M 4.3 in  The Andreanof Islands and in Central Alaska. The event in the Andreanof Islands was not reported felt and is the furthest east event of M>=4.3 in the Andreanof group during the year 2017. It was not felt in this remote epicentral area. Forecast 109003 had expected this event within about 100 km of this epicenter was likely around July 12.

 

O: 14JUL2017 03:11:49  51.8N  172.7W mb=4.3  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P: 12JUL2017 109003    52.1N  171.3W 3.5-5.0 AAAAA  Andreanoff Isls, Aleutians 

 

The last earthquake of M>=4.3 within about 100 km of today's epicenter in Central Alaska was an M 4.2 on May 2, an aftershocks of an M 5.3 on April 29, 2017. Forecast 109027 had expected this event within about 50 km of the epicenter was likely around July 16.

 

O: 14JUL2017 00:09:14  63.2N  151.0W mb=4.3  EMSC   CENTRAL ALASKA               

P: 16JUL2017 109027    62.6N  151.4W 3.2-5.1 AAAAA  Central Alaska             

 

A strong swarm of earthquakes hit the Mammoth Lakes region near the California-Nevada border today. The strongest of these was an M 2.9. The area became active after the M 6.6 in Leyte, Philippines last week and has seen several swarms since then. Mammoth Lakes is at 103 degrees from the Leyte epicenter and was probably promoted by concentrated seismic energy from that source.

 

NEIC reported this earthquake of M 2.5 in Mammoth Lakes, California was felt with intensity II-III in the area(s) of Kelseyville and Clearlake, California.

Most of today's events occurred during the period between 02:00 and 03:00 am local time and suggest a tidal influence in the timing. Forecast 108910 had expected this activity was likely around July 14.

 

O: 13JUL2017 10:58:56  37.6N  118.8W md=2.6  ANSS   Mammoth Lakes California

O: 13JUL2017 10:57:46  37.6N  118.8W md=2.6  ANSS   Mammoth Lakes California

O: 13JUL2017 10:57:02  37.6N  118.8W md=2.5  ANSS   Mammoth Lakes California

O: 13JUL2017 10:55:24  37.6N  118.8W md=2.5  ANSS   Mammoth Lakes California

O: 13JUL2017 10:54:07  37.6N  118.8W md=2.4  ANSS   Mammoth Lakes California

O: 13JUL2017 10:53:45  37.6N  118.8W md=2.9  ANSS   Mammoth Lakes California

O: 13JUL2017 10:52:49  37.6N  118.8W md=2.1  ANSS   Mammoth Lakes California

O: 13JUL2017 10:52:44  37.6N  118.8W md=2.5  ANSS   Mammoth Lakes California

O: 13JUL2017 10:48:31  37.6N  118.8W md=2.9  ANSS   Mammoth Lakes California

O: 13JUL2017 10:10:24  37.6N  118.8W md=2.2  ANSS   Mammoth Lakes California

O: 13JUL2017 10:07:44  37.6N  118.9W md=2.1  ANSS   Mammoth Lakes California

O: 13JUL2017 10:07:33  37.6N  118.8W md=2.6  ANSS   Mammoth Lakes California

O: 13JUL2017 19:46:22  37.5N  118.8W Md=2.2  EMSC   CENTRAL CALIFORNIA           

O: 13JUL2017 10:58:56  37.6N  118.8W MD=2.6  EMSC   LONG VALLEY AREA, CALIFORNIA 

O: 13JUL2017 10:10:24  37.6N  118.8W Md=2.2  EMSC   LONG VALLEY AREA, CALIFORNIA 

O: 13JUL2017 10:07:33  37.7N  118.8W MD=2.5  EMSC   LONG VALLEY AREA, CALIFORNIA 

O: 13JUL2017 10:52:44  37.7N  118.8W MD=2.5  EMSC   LONG VALLEY AREA, CALIFORNIA 

O: 13JUL2017 10:55:24  37.7N  118.8W MD=2.5  EMSC   LONG VALLEY AREA, CALIFORNIA 

O: 13JUL2017 10:57:46  37.7N  118.8W MD=2.6  EMSC   LONG VALLEY AREA, CALIFORNIA 

O: 13JUL2017 10:48:31  37.7N  118.8W MD=2.9  EMSC   LONG VALLEY AREA, CALIFORNIA 

O: 13JUL2017 10:53:45  37.7N  118.8W MD=2.9  EMSC   LONG VALLEY AREA, CALIFORNIA 

P: 14JUL2017 108910    37.3N  118.3W 2.5-4.4 AAAAA  California/Nevada area     

 

An unusual earthquake of M 3.5 hit in the southern Virgin Islands today. NEIC reported this earthquake of M 3.5 in the Virgin Islands was felt with intensity II-III in the area(s) of Saint John and Saint Thomas, Virgin Islands; Road Town, Tortola, British Virgin Islands and Blowing Point, Anguilla. This is the strongest earthquake within about 100 km of this epicenter in the Virgin Islands since an M 3.6 on March 23 and an M 3.8 on January 8, 2017. Forecast 108877 had expected a light to moderate quake in the region was possibly around July 15. Tidally promoted seismicity in this area had been expected with high stresses around the full moon as noted in this summary in previous issues:

 

"The full moon arrived at 04:07 UT on July 9, 2017. Longitudinal zones which were sub-solar at this time lie near 120 degrees East longitude and 60 degrees

west longitude and include area of Japan, the Philippines and Indonesia in the

east and the Caribbean and South America in the West. These are the most likely area to see strong tidal triggering with this full moon, and some of this may have already begun. Tidal triggering is not limited to these area, however,  as many regions respond with promoted seismic activity during full and new moons." (July 7-11, 2017).

 

O: 13JUL2017 23:23:35  18.3N   64.7W MD=3.5  EMSC   VIRGIN ISLANDS REGION        

P: 15JUL2017 108877    18.0N   64.0W 3.0-5.3 AAAAA  Leeward Islands            

 

STRONG QUAKE IN NEW IRELAND

 

EARTHQUAKE SUMMARY FOR JULY 12, 2017

 

A strong earthquake of M 6.3 hit the region of New Britain/Ireland today. NEIC reported it was felt with intensity VI in Kokopo, East New Britain and II-II in Rabaul, East New Britain and in New Ireland at Namatanai, Papua, New Guinea.

New Britain and New Ireland are in a highly seismic zone and often experience strong earthquakes but currently the region is experiencing a seismic lull.

The last earthquake within about 150 km of today's epicenter with M>=6.4 occurred on  December 17, 2016 with M 7.9. Today's event is probably an aftershock, the largest to date of that earthquake. Forecast 108852 had expected today's event was likely within about 100 km of this epicenter around July 15. As today's event occurred within 10 degrees of the geomagnetic equator and within about an hour of local solar noon, it is likely that both tidal and geomagnetic effects helped promote this event at this time.

 

O: 13JUL2017 03:36:08   4.8S  153.2E Mw=6.4  EMSC   NEW IRELAND REGION, P.N.G.   

O: 13JUL2017 04:02:35   4.9S  153.2E mb=4.8  EMSC   NEW IRELAND REGION, P.N.G.   

P: 15JUL2017 108852     5.0S  154.0E 4.0-5.4 AAAAA  New Britain                

 

Moderately large earthquakes also hit deep under the Sea of Japan (M 5.9) and off the coast of Maule, Chile (M 5.5). The event under the Sea of Japan lies at 102-103 degrees from the eye of TS Fernanda, a new storm which formed today south of Mexico. Microseisms can disturbed this distance and can help promote seismicity as previously noted in this summary:

 

"TS  FERNANDA   2017-07-13  00:00 UT  11.9N  112.6W  050 kts  southwest of Mexico                 

 

TS Fernanda formed today south of western Mexico with winds up to 45 kts. It is expected to track to the west over the next week far from land. No seismic watch is expected with this storm. The antipode at 11S 66E is in the South Indian Ridge where a promoted storm is possible. The area of Kyushu, Japan lies at 103 degrees from the eye of Fernanda and may see promoted activity. A moderately strong quake of M 5.9 in the Sea of Japan today also lies at 102-103 degrees from the eye of Fernanda and may have been promoted by microseisms from that storm. The region of Czech Republic is also at 103 degrees from this eye and part of the activity there may  have been promoted from this storm." (July 12, 2017)

 

The last earthquake of M>=5.5 in the Sea of Japan was an M 5.6 on March 27, 2017. The last of M>=5.9 occurred on April 6, 2013 with M 5.9. This was an aftershock of an M 6.4 on April 5, 2013.  Forecast 108714 had expected this event within about 150 km of this epicenter was likely in early July.

 

NEIC reported this earthquake of M 5.9 in the Sea of Japan was felt with intensity II-III in the area(s) of North Korea at Chongjin, Hamgyongbukto and in Pyongyang.

 

O: 12JUL2017 19:48:06  40.9N  131.8E Mw=5.9  EMSC   SEA OF JAPAN                 

P:  1JUL2017 108714    41.0N  129.0E 3.5-5.4 CABAA  NE China                   

 

An earthquake of M 5.5 off the coast of central Chile near Bio Bio today was felt with intensity II-III in Chile at Concepcion, Bio Bio; Machali, O'Higgins, Valparaiso, Quilpue and Vina del Mar, Valparaiso. CSN reported this earthquake was felt with intensity  IV in  Constitucion, Cauquenes, Pelluhue; III San Fernando, Santa Cruz, Molina, Talca; II Rancagua, Felt in Maule and O'Higgins, Chile. A larger earthquake of M 5.9 hit the same epicenter on July 4. This is probably an aftershock of that earthquake and the second strongest in the Maule, Chile region during 2017. Forecast 108807 had expected this earthquake within about 100 km of the epicenter was likely around July 9-11. It is located at the seventh node (51.4 degrees) from the Guatemala earthquakes of June 14 and 22 of M 6.8-6.9 and may have been promoted from those sources.

 

 

O: 12JUL2017 09:08:18  35.4S   73.1W Mw=5.5  EMSC   OFFSHORE MAULE, CHILE

O: 12JUL2017 08:19:52  35.4S   73.3W mb=4.5  EMSC   OFFSHORE MAULE, CHILE

O: 12JUL2017 09:08     35.3S   73.4W mb=5.5  GUC    Constitucion, Cauquenes, Pellu

P:  9JUL2017 108807    36.0S   72.0W 4.0-5.7 BAAAA  Central Chile              

P: 11JUL2017 108807    37.0S   73.0W 4.0-5.6 ABAAA  Central Chile              

 

The most unusual earthquake in the U.S. or Canada today occurred near Saint George, Utah. NEIC reported this earthquake of M 3.4 in Utah was felt with intensity II-III in the area(s) of Utah at Saint George, Santa Clara, Washington, Ivins, Hurricane. It is the largest earthquake in the area of Arizona during the year 2017. The last earthquake of M>=3.4 within about 100 km of this epicenter occurred on May 5, 2016 of M 3.8 about 100 km northwest of this epicenter.  Forecast 108929 had expected a moderate earthquake within this area was likely around July 12.

 

O: 12JUL2017 14:41:50  37.0N  113.6W ML=3.4  EMSC   ARIZONA                      

O: 12JUL2017 14:41:50  37.0N  113.6W ml=3.4  ANSS   Saint George Utah

P: 12JUL2017 108929    37.3N  114.9W 2.5-4.5 AABAA  Nevada area

 

EARTHQUAKE SWARM HITS CZECH REPUBLIC AFTER NEW ZEALAND M 6.6

 

EARTHQUAKE SUMMARY FOR JULY 11, 2017

 

The antipodal region of the M 6.6 off Southern New Zealand which occurred early on July 11 lies in the area of northern Western Europe. Shortly after the New Zealand event a strong series of light earthquakes occurred in this area in the Czech Republic which may have been promoted from New Zealand. The largest of the Czech events was M 3.4 but a series of events of M 2.0-3.4 also accompanied that earthquake. The strongest of these occurred within about 30 minutes of local solar noon and tidal promotion associated with the full moon is also a likely trigger. EMSC reported these events were felt with light to moderate intensity in the Czech Republic at Kraslice, Nova Role, Lomnice and Cheb,  and in Germany at Truen and Wilkau-Hasslau. Oelsnitz, Markneukirchenand Adorf. This is the first significant activity in the Czech Republic during 2017. The last event within about 200 km of these epicenters with M>=3.4 occurred on May 31, 2014; an M 4.0 on September 3, 2011 and an M 4.2 on October 28, 2008. The last swarm similar to today's in the area occurred beginning on October 9, 2008 and lasted through October 28, 2008. The rarity of today's activity and the juxtaposition with the near-antipodal New Zealand event strongly suggests promotion from that source. It is also at 103 degrees from the M 6.8 in the Celebes of May 29 and may have been promoted from that event. Forecast 108746 had expected a moderate event in the are was likely around July 5.

 

O: 11JUL2017 19:17:23  50.3N   12.4E ML=2.7  EMSC   CZECH REPUBLIC               

O: 12JUL2017 05:46:57  50.3N   12.4E ML=2.8  EMSC   CZECH REPUBLIC               

O: 11JUL2017 11:25:35  50.3N   12.4E ML=3.2  EMSC   CZECH REPUBLIC               

O: 11JUL2017 11:58:09  50.3N   12.4E ML=3.4  EMSC   CZECH REPUBLIC               

P:  5JUL2017 108746    50.0N   13.0E 3.0-4.7 CAAAA  No. Germany                

 

The strongest earthquake in the world today was an M 5.3 near the coast of Ecuador. NEIC reported this earthquake of M 5.3 in Ecuador was felt with intensity IV in Muisne, Esmeraldas, Ecuador and II-III in the area(s) of Ecuador at Esmeraldas, Quito, Guaranda, Puyo, Guayaquil, Guayas, and possibly in Quiteno, Panama. This epicenter is near 103 degrees from the M 6.6 off Southern New Zealand and occurred about 5 hours after that event. It is likely that it was promoted by concentrated seismic energy from that source. Among other earthquakes at this distance from New Zealand today were events in the Near Islands, Central and southern California, eastern Mexico, and off the Oregon coast. The last earthquake within about 150 km of this epicenter with M>=5.3 occurred on January 31, 2017 with M 5.4. Ecuador saw an M 6.1 about 200 km from this epicenter on June 30. Forecast 108588 expected today's event as an aftershock of the June 30 earthquake.

 

O: 11JUL2017 12:09:17   0.7N   79.7W Mw=5.3  EMSC   NEAR COAST OF ECUADOR        

P:  9JUL2017 108588     1.0S   81.0W 4.0-5.6 ABBAA  Ecuador                    

 

An unusual earthquake of M 5.0 in the Scotia Sea south of South America today may have been tidally promoted. This event occurred near local solar midnight in a longitude zone where expected seismic triggering from the full moon was considered likely in the tidal forecast:

 

"The full moon arrived at 04:07 UT on July 9, 2017. Longitudinal zones which were sub-solar at this time lie near 120 degrees East longitude and 60 degrees west longitude and include area of Japan, the Philippines and Indonesia in the east and the Caribbean and South America in the West. These are the most likely area to see strong tidal triggering with this full moon, and some of this may have already begun. Tidal triggering is not limited to these area, however,  as many regions respond with promoted seismic activity during full and new moons." (July 7-11, 2017).

 

This event was not felt in this remote area. Two earthquakes in the Scotia Sea area this year have had higher magnitudes - an M 5.8 about 500 km east of this on May 6 and an M 5.3 about 150 km west of this on February 22. Forecast 108830 had expected this event within about 250 km of this epicenter in early July.

 

O: 11JUL2017 22:38:46  60.3S   48.7W mb=5.0  EMSC   SCOTIA SEA                   

P:  1JUL2017 108830    60.0S   44.0W 3.0-5.5 CABAA  So. So. America            

 

The strongest earthquake in the U.S. or Canada today was an M 4.1 in the Rat Islands, Aleutians, Alaska. It was not reported felt in this remote area. The Rat Islands are an active area and the last event in the area of M>=4.1 was an M 5.0 on June 21, 2017. Forecast 109015 had expected today's earthquake within about 50 km of the  epicenter was likely around July 13.

 

O: 11JUL2017 23:42:42  50.7N  178.9E mb=4.1  EMSC   RAT ISLANDS, ALEUTIAN ISLANDS

P: 13JUL2017 109015    51.0N  178.0E 4.0-5.8 AAAAA  Rat Islands                

 

An earthquake of M 4.1 also occurred off the coast of Oregon today but was not felt on the mainland. The only other event within about 250 km of this epicenter off the Oregon Coast during 2017 of similar or larger magnitude was an M 4.4 on May 13. Forecast 108987 had expected today's earthquake was likely around July 14.

 

O: 12JUL2017 03:41:14  44.1N  129.2W mb=4.1  EMSC   OFF COAST OF OREGON          

P: 14JUL2017 108987    44.4N  129.3W 3.0-4.4 AAAAA  Off Coast of Oregon        

 

STRONG EARTHQUAKE RATTLES SOUTHERN NEW ZEALAND

 

EARTHQUAKE SUMMARY FOR JULY 10, 2017

 

An earthquake of M 6.6-6.8 hit the Auckland Islands area south of New Zealand today. EMSC reported it was felt as a rattling more than 500 km to the north in Port Chalmers, New Zealand. NEIC reported moderate shaking throughout South Island including IV at Bluff and Wallacetown and II-III in Tuatapere, Invercargill, Woodlands, Winton, Wyndham, and Gore, Te Anau, Southland and in Otago at Owaka, Clinton, Milton, Queenstown, Dunedin, Waitati, Wanaka and in Christchurch, Canterbury and as far to the north as Reefton and Wellington as far as 1250 km north of the epicenter. Residents reported a rolling sensation for about 20-30 seconds. PTWC did not issue a tsunami watch or warning for this event. GEONET reported it was felt with light intensity in the Southland area and gave a preferred magnitude of M 6.4 but local magnitudes up to M 7.4. There was 1928 felt reports mostly from southern South Island, New Zealand. These included 1227 of weak shaking. Light intensity was felt by 614 and moderate intensity by 82 persons. Strong to extreme shaking was reported by 5 persons with one experiencing severe shaking. This epicenter is at the third node (120 degrees) from the M 5.9 in Montana and near the 103 degree distance from the strong earthquakes in Guatemala of June 14 and 22 (M 6.9). It is likely that it was promoted by energy from these events. It is also likely this high latitude earthquake was promoted by the full moon tidal stresses and by the geomagnetic storm yesterday. This summary had noted in previous issues in regard to this geomagnetic storm:

 

" stormy conditions in the geomagnetic field at this time are being brought on by more flare activity on the sun, the first significant flare activity in several months. This initially should lead to an increase in seismicity especially at sub- and anti-solar longitudes and near the geomagnetic equator. This increase is likely to be followed by several additional days of quiet and several days of high seismicity around July 12-15 as newly incorporated electrons become part of re-energized equatorial and auroral ring currents." (July 10, 2017)

 

Recent earthquakes in the Auckland Islands area occurred on May 22 and 24 (M 4.8-4.9) and on June 6, 2017 (M 4.5) and may have been foreshocks to today's event. The last earthquake with M>=6.5 in the region occurred on September 30, 2007 with an M 7.4 and 6.6 ten years ago. A great earthquake hit the region December 23, 2004, two days before the great tsunamigenic Sumatra earthquake which caused more than 200,000 deaths around the Indian Ocean. While the size of today's event does not compare with that of December, 2004 (M 8+), Sumatra could see moderate to large triggering in the next several days. The December 23 and 24, 2004 issues of this summary noted a strong increase in seismicity in southern South Island after the great quake there and the possibility of major "very dramatic" seismicity elsewhere in the world especially near 103 degrees - a zone which includes southern California among others. Today’s epicenter is also located at 103 degrees from the eye of Hurricane Eugene west of Mexico and may have been promoted by microseisms from that event. Forecasts 108824 and 109086 had expected a moderate earthquake in this area between July 10 and 12, 2017.

 

O: 11JUL2017 07:00:11  49.1S  164.5E Mw=6.5  EMSC   AUCKLAND ISLANDS, N.Z. REGION

O: 11JUL2017 07:00:12  48.9S  164.4E ML=7.4  GEONET Felt with light intensity in the Southland area.

P: 10JUL2017 108824    46.0S  167.0E 3.0-5.2 ACBAA  Southern S. Isl. N.Z.      

P: 12JUL2017 109086    46.0S  167.0E 3.0-5.1 ACBAA  Southern S. Isl. N.Z.      

 

The strongest earthquake in the U.S. or Canada today occurred in Southern Alaska with M 4.3. NEIC reported it was felt with intensity II-III in Valdez, Eagle River, Anchorage and Chugiak, Alaska. The only earthquake of larger magnitude in Southern Alaska within about 150 km  of this epicenter during 2017 was an M 4.6 about 150 km north of this on May 29. Forecast 108759 had expected today's event was likely within about 25 km of the epicenter around July 9.

 

O: 11JUL2017 09:41:11  60.4N  147.4W Ml=3.0  EMSC   SOUTHERN ALASKA              

O: 11JUL2017 09:30:26  60.5N  147.4W ML=4.3  EMSC   SOUTHERN ALASKA               

P:  9JUL2017 108759    60.6N  147.6W 3.2-5.3 AAAAA  Central Alaska             

 

TIDAL AFTERSHOCK HITS LEYTE, PHILIPPINES

 

EARTHQUAKE SUMMARY FOR JULY 9, 2017

 

An aftershock of M 5.9 hit the area of Leyte, Philippines where an M 6.5 occurred two days ago. NEIC reported it was felt with maximum intensity VI in Valencia, Eastern Visayas and V in Pawing and Tangke (Naga, Cebu) Central Visayas. Intensity IV was reported from Gabi, San Antonio and Tunga, Eastern and Central Visayas. Lesser shaking of intensity II-III was reported from the eastern and central Visayas at Ga-as, Palompon, Tabunok, Carmen, Gogon-Cruz, Consolacion, Lapu-Lapu, Mandaue, Mandawa, Dapitan, Cebu, Calero and Minglanilla, Philipines. PHIVOLCS reported it was felt with intensity VI in Ormoc City; V in Kanaga, Leyte; IV in Mayorga, Leyte; Tacloban City; Mandaue City; III in Loay, Maribojoc and Jagna, Bohol, Cebu City ?Talisay City, Cebu; II in Lapu-Lapu City; Cadiz City Negros Occidental; Iloilo City; Tabogon, Cebu and I in Guihuingan, Negros Oriental, Philippines. Slight damage is likely in the epicentral area. At 124 East longitude and occurring within several hours of local solar noon, this event is consistent with strong promotion by high tidal stresses associated with the full moon today as previously noted in this summary:

 

"The full moon will arrive at 04:07 UT on July 9, 2017. Longitudinal zones which are sub-solar at this time lie near 120 degrees East longitude and 60 degrees west longitude and include area of Japan, the Philippines and Indonesia in the east and the Caribbean and South America in the West. These are the most likely

area to see strong tidal triggering with this full moon, and some of this may

have already begun. Tidal triggering is not limited to these area, however," (July 5-9, 2017)

 

This is the largest aftershock to date in this region of Leyte, Philippines. Forecast 108878 had expected a moderately strong aftershock around July 12.

This may be an example of seismic ping-pong. This occurs when a strong earthquake is followed by a second strong preferred distance which is followed by a strong aftershock at the original location etc. In this case Leyte is located at 103 degrees from the M 5.9 in Western Montana which occurred 90 minutes before it. An upswing in Mammoth Lakes, California seismicity, where an M 3.9, the strongest in the current year, 2017, occurred, was also noted at this distance to the Philippines. Seismicity at 103 degrees from large earthquakes often increases following those events and is thought to be promoted by strong concentrations of seismic energy returning to the surface at this distance after reflections and refractions off the core-mantle boundary.

 

O: 10JUL2017 01:41:47  11.0N  124.7E MS=5.8  PHI  Felt with intensity VI in Ormoc

O: 10JUL2017 01:41:49  11.0N  124.8E Mw=5.9  EMSC   LEYTE, PHILIPPINES           

P: 12JUL2017 108878    11.0N  126.0E 3.5-5.2 AAAAA  Luzon, Philippines         

 

A second earthquake, probably tidally promoted, was the second largest event of the day. At M 5.5-5.6 in the South Sandwich Islands, it occurred about an hour after the full moon in an area where tidal stresses were high and was probably promoted by the full moon alignment. Earthquakes in this remote area are seldom felt and today's event was not an exception to this. An earthquake of M 6.4 hit about 200 km southeast of this epicenter on May 10 but no events of this magnitude have occurred in the South Sandwich Islands closer than 200 km to this epicenter during the current year, 2017. Forecast 108829 had expected today's event within about 25 km was likely around July 10.

 

O:  9JUL2017 05:57:03  56.2S   27.5W mb=5.5  EMSC   SOUTH SANDWICH ISLANDS REGION

O: 09JUL2017 05:57:02  56.1S   27.7W mb=5.6  ANSS   the South Sandwich Islands

P: 10JUL2017 108829    56.0S   28.0W 4.0-5.8 AAAAA  So. Sandwich Islands       

 

An unusual (outer-rise?) earthquake of M 3.6 hit north of the Virgin Islands and the northeastern Caribbean Sea today. At 20N latitude it is far north of the normal background seismicity of the region and was not felt in the Virgin Islands to the south. The last earthquake within about 50 km of this epicenter with M>=3.6 was an M 4.5 on September 28, 2012 about 25 km north of today's epicenter. Outer rise quakes occur on the outer rise of the subducting plate (the North American plate subducting beneath the Caribbean plate) and are thought by some to indicate regions of stress build-up where a strong earthquake could be close down the subduction zone. Forecast 108615 had expected a moderate quake in the area around July 9. This epicenter is at 64 degrees West longitude and appears to have been promoted by high tidal stresses associated with the full moon today which maximized near this longitude (see tidal description above).

 

O:  9JUL2017 21:58:41  20.0N   64.2W ML=3.6  EMSC   NORTH OF THE VIRGIN ISLANDS  

P:  9JUL2017 108615    18.0N   64.0W 3.0-5.4 ABAAA  Leeward Islands            

 

The strongest earthquake in the U.S. or Canada today was an M 4.3 in the Kenai Peninsula of Alaska. NEIC reported it was felt with intensity II-III in West Kenai Peninsula Boroug, Anchor Point, Homer, Kenai, Anchorage, Seward, Girdwood, Eagle River and Chugiak, Alaska. The only other earthquake during 2017 within about 100 km of this epicenter in southern Alaska with M>=5.3 occurred as an M 5.5 on March 2 about 50 km east of today's epicenter. An earthquake of M 4.6 in Southern Alaska about 350 km northeast of this occurred on May 29. Forecast 109024 had expected today's event within about 100 km of the epicenter was likely around July 13.

 

O: 10JUL2017 04:31:08  59.7N  153.1W ML=4.3  EMSC   SOUTHERN ALASKA              

P: 13JUL2017 109024    60.2N  151.7W 3.2-5.0 BAAAA  Central Alaska             

 

The largest earthquakes in California today were an M 3.7 in northern California near Hayfork and an M 3.9 in the Mammoth Lakes area. NEIC reported the event in northern California was felt with intensity II-III in Bridgeville, Myers Flat, McKinleyville, Garberville, Dunsmuit, and possibly Sacramento. The Mammoth Lakes event was felt with intensity IV in June Lake, California northwest of Mammoth Lakes. The last earthquake of M>=3.9 in the Mammoth Lakes region of California within  about 50 km of this epicenter occurred December 14, 2016 with M 4.0 and prior to that on February 16, 2016 (M 4.3, 4.8).  Forecast 108910 had expected activity in the Mammoth Lakes area around June 14. Like Western Montana, Mammoth Lakes is located at 103 degrees from Leyte, Philippines and this activity is likely promoted by energy from that region.

 

O:  9JUL2017 15:55:26  37.5N  118.8W MD=2.3  EMSC   CENTRAL CALIFORNIA            

O: 10JUL2017 06:43:44  37.5N  118.8W MD=2.6  EMSC   CENTRAL CALIFORNIA           

O:  9JUL2017 15:48:01  37.5N  118.8W MD=2.7  EMSC   CENTRAL CALIFORNIA           

O: 10JUL2017 07:30:27  37.5N  119.0W MD=2.6  EMSC   CENTRAL CALIFORNIA           

O:  9JUL2017 09:12:05  37.5N  119.0W ML=3.5  EMSC   CENTRAL CALIFORNIA           

O: 09JUL2017 09:12:05  37.5N  119.0W mw=3.9  ANSS   S of Mammoth Lakes

P: 14JUL2017 108910    37.3N  118.3W 2.5-4.4 BAAAA  California/Nevada area     

 

The last earthquake with M>=3.7 within about 50 km of the earthquake in Northern California today occurred on February 3, 2017 with M 3.7. The last of larger magnitude was an M 4.5 on August 28, 2016.  Forecast 108985 had expected this event within this area in mid-July.

 

O: 10JUL2017 01:44:12  40.6N  123.3W Mw=3.7  EMSC   NORTHERN CALIFORNIA          

P: 15JUL2017 108985    40.0N  123.0W 2.5-4.7 BAAAA  Northern California        

 

GLOBAL SEISMICITY TAKES A BREATHER

 

EARTHQUAKE SUMMARY FOR JULY 8, 2017

 

Global seismicity was at quiet levels in most areas of the world today. The largest event of the day was an M 5.2 in Sumatra where it was lightly felt. There were no moderately large or large earthquakes recorded today. This is expected to change with the coming of the full moon today as noted in previous issues of this summary:

 

 

"The full moon will arrive at 04:07 UT on July 9, 2017. Longitudinal zones which are sub-solar at this time lie near 120 degrees East longitude and 60 degrees west longitude and include area of Japan, the Philippines and Indonesia in the east and the Caribbean and South America in the West. These are the most likely area to see strong tidal triggering with this full moon, and some of this may

have already begun. Tidal triggering is not limited to these area, however," (July 5-9, 2017)

 

O:  8JUL2017 22:48:39   7.4S  106.0E mb=5.2  EMSC   JAVA, INDONESIA              

P:  9JUL2017 108599     9.0S  109.0E 4.0-5.4 ABCAA  So. of Java                

 

In the U.S. and Canada the largest earthquakes of the day were a pair of events of M  3.5 in the aftershock zones of Montana and southeastern Alaska. The events in Montana continued an active aftershocks sequence which has been continuing since the mainshock of July 5. No damages or injuries were associated with  either of these events which had been anticipated in forecasts 108977 and 108753 to occur around July 10-12.

 

NEIC reported these earthquakes of M 2.7 and M 2.8 in West Yellowstone, Montana were felt with intensity II-III in the area(s) of Butte and Helena, Montana and at Ashton, Idaho.  The strongest of these was an M 4.1 felt with intensity II-III in Montana at Missoula, Choteau,. Great Falls, Townsend, Clancy, Canyon Creek, Helena, Garrison and Lincoln, Montana and in Banff, Alberta, Canada.

 

O:  8JUL2017 12:42:37  46.9N  112.5W ML=2.6  EMSC   WESTERN MONTANA              

O:  8JUL2017 16:23:38  46.9N  112.5W ML=2.8  EMSC   WESTERN MONTANA              

O:  9JUL2017 01:59:37  46.9N  112.5W ML=3.0  EMSC   WESTERN MONTANA              

O:  8JUL2017 12:56:31  46.9N  112.6W ML=3.5  EMSC   WESTERN MONTANA              

P: 12JUL2017 108977    46.7N  112.1W 2.0-4.2 AAAAA  Montana/Idaho              

 

O:  8JUL2017 18:17:21  59.9N  136.7W ML=3.5  EMSC   SOUTHEASTERN ALASKA          

P: 10JUL2017 108753    59.0N  137.0W 3.0-4.4 AAAAA  Southeast Alaska           

 

MODERATELY STRONG EVENTS IN LOYALTY ISLANDS; HONSHU, JAPAN

 

EARTHQUAKE SUMMARY FOR JULY 7, 2017

 

The strongest earthquake of the day was an M 5.6 in the Loyalty Islands of the southwest Pacific. This is a remote area and this event was not reported felt. At 97 degrees from the M 5.8 in Montana, it is close to the 103 degree distance from that event shared by the M 6.5 in Leyte, Philippines and the M 5.8 yesterday in Papua New Guinea and may have been promoted from the Montana source like these previous events. Today's event is the strongest in the Loyalty Islands during 2017. An event of M 5.5 occurred on March 7, 2017. The last of larger magnitude within about 200 km of today's epicenter was an M 7.2 on August 12, 2016 and is probably the largest aftershock of that event to date.  Forecast 108791 had expected today's event within about 100 km of the epicenter was likely around July 8.

 

O:  8JUL2017 07:27:39  22.5S  173.1E Mw=5.6  EMSC   SOUTHEAST OF LOYALTY ISLANDS 

P:  8JUL2017 108791    23.0S  172.0E 4.0-5.4 AAAAA  Loyalty Islands            

 

The most widely felt earthquake today occurred off the eastern coast of Honshu,

Japan. NEIC reported it was felt with maximum intensity V in Koriyama, Fukushima and IV in Sendai, and Kakuda, Miyagi and Hitachi, Ibaraki, Honshu, Japan. Intensity II-III was also felt in Sukagawa, Fukushima, Mito, Tsukuba, Tsuchiura, Nake, Kukizaki, Narita, Ibaraki,in Narita and Funabashi Chiba, Ageo and Kawagoe, Saitama, in Tochigi at Utsunomiya and Moka and in Tokyo, Japan.  As suggested in earlier issues of this summary this may have been promoted by stresses from Tropical Storm Nanmadol:  

 

"Tropical Storm Nanmadol (05W) passed over Tokyo, Japan with winds up to 40 kts today. It is expected to dissipate over the next day.  While this is not a strong storm the location of the eye could reduce normal friction along the Japanese subduction zone making a strong earthquake in the area likely at this time. This is the first storm of the new typhoon season, and while not large, it  could have seismic triggering potential for the area. Japan is under a seismic watch through July 7. A moderate to strong quake may occur in the  subduction zone of eastern or southern Japan during this period." (July 5, 2017)

 

Activity in the epicentral zone has been slow since the March 11, 2011 great shock which initiated near this epicenter. The last event of M>=5.1 within  about 100 km of this epicenter occurred on February 28, 2017 with M 5.7 and an aftershock of M 5.4 on March 11, 2017. Forecast 108691 had expected this event within about 150 km of the epicenter around July 4.

 

O:  7JUL2017 12:48:36  37.8N  141.1E mb=5.1  EMSC   NEAR EAST COAST OF HONSHU, JAP

P:  4JUL2017 108691    38.0N  143.0E 4.0-5.4 BABAA  So. of Honshu              

 

The strongest earthquake in the U.S. or Canada today occurred in southern Alaska with M 4.1 near Kalifornsky, Alaska. NEIC reported it was felt with light intensity in Alaska at Kasilof, Soldotna, Sterling, Anchor Point, Kenai, Tyonek, Homer, Anchorage, Seward, Girdwood, Wasilla, Eagle Rive and Talkeetna, Alaska.

The largest earthquakes in the Kenai Peninsula, Alaska during 2017 were an event of M 5.5 on May 30 and an M 5.2 on May 7. These were the only other events of

M>=4 this year. Forecast 108760 had expected today's activity within about 25 km of this epicenter around July 9.

 

O:  7JUL2017 14:28:53  60.3N  152.6W Ml=3.4  EMSC   SOUTHERN ALASKA              

O:  7JUL2017 07:58:17  60.5N  151.8W ML=4.4  EMSC   KENAI PENINSULA, ALASKA      

P:  9JUL2017 108760    60.5N  151.5W 3.2-5.0 AAAAA  Central Alaska             

 

Aftershocks of the M 5.8 earthquake in Montana also continued today. These were reported felt in Montana at Helena, Butte, Kalispell and Columbia Falls with intensity II-III. Forecast 108977 expected this activity to continue through mid-July.

 

O:  7JUL2017 20:28:58  46.9N  112.5W ML=2.0  EMSC   WESTERN MONTANA              

O:  7JUL2017 11:20:20  46.9N  112.5W ML=2.3  EMSC   WESTERN MONTANA              

O:  7JUL2017 08:10:52  46.9N  112.5W ML=2.4  EMSC   WESTERN MONTANA              

O:  7JUL2017 06:48:41  46.9N  112.7W ML=2.5  EMSC   WESTERN MONTANA              

P: 12JUL2017 108977    46.7N  112.1W 2.0-4.2 BAAAA  Montana/Idaho              

 

MODERATELY STRONG QUAKE IN EASTERN NEW GUINEA AT 102 DEGREES FROM MONTANA

 

EARTHQUAKE SUMMARY FOR JULY 6, 2017

 

The strongest earthquake in the world today occurred in Eastern New Guinea with M 5.7. NEIC reported this earthquake of M 5.7 in Papua New Guinea was felt with intensity II-III in the area(s) of Lae, Morobe; Kainantu, Eastern Highlands and Port Moresby, Papua New Guinea. Like the M 6.5 in Leyte, Philippines yesterday, this event is also located at 102-103 degrees from the M 5.8 in Montana of July 6. In the previous report it was noted:

 

"A moderately strong earthquake of M 5.8 in western Montana today may have helped trigger an M 6.2 earthquake in Leyte, Central Philippines about an hour and-a-half later. The two epicenters are separated by 103 degrees on the earth's surface. Seismic energy from large events reflects and refracts off core-mantle boundaries and is redirected to the surface where it concentrates around  103 degrees from the mainshock epicenter. A surge in seismicity in this distance zone often follows and is thought to be triggered by this energy." (July 6, 2017)

 

This event occurred near local solar noon and may have been promoted by tidal stresses which are strong at this time. Tidal stress at this longitude was high during the previous new moon as noted in this summary:

 

 

"The new moon arrived on June 24 at 02:31 UT. Areas which were sub-solar at this time lie within about 20 degrees longitude of 145 East longitude while those anti-solar areas are near 35 West longitude. These include the mid-Atlantic Ocean region in the west and Japan and the western Pacific subduction zone in the east. These regions are most likely to see a strong to major earthquake during the period June 22-26 but tidal enhancement of seismicity can occur in many tectonic settings and is most likely near local solar midnight and noon at this time." (June 22-27, 2017)

 

The only earthquake of larger magnitude in the region of Eastern New Guinea during the year 2017 was an M 5.9 on January 8 and this may be an aftershock of that event, the strongest to date. Forecast 108594 had expected a moderately strong earthquake in this region around July 7. Like the M 6.5.

 

O:  7JUL2017 03:42:52   6.7S  148.0E Mw=5.7  EMSC   EASTERN NEW GUINEA REG., P.N.G

P:  7JUL2017 108594     7.0S  145.0E 4.0-5.6 AACAA  New Ireland                

 

Aftershocks continued to be felt in western Montana today. The strongest of these were around M 4.0. They were reported by NEIC to have been felt in Montana at Clancy with intensity IV and with intensity II-III in Helena, East Helena, Missoula, Corvallis, Great Falls, Hamilton, Belgrade, Polson, Bozeman, Whitefish and Billings, Montana and perhaps in Idaho and Washington. These are aftershocks of yesterday's M 5.8 which was widely felt throughout northwestern U.S. and southwestern Canada. Forecast 108977 had expected  this activity in Montana in early July.

 

O: 06JUL2017 11:46:38  46.9N  112.5W ML=2.5  EMSC   WESTERN MONTANA

O: 06JUL2017 10:04:07  46.9N  112.5W ML=2.9  EMSC   WESTERN MONTANA

O: 06JUL2017 10:54:10  46.9N  112.5W ML=2.9  EMSC   WESTERN MONTANA

O: 06JUL2017 10:44:52  46.9N  112.5W ML=3.4  EMSC   WESTERN MONTANA

O: 06JUL2017 13:15:43  46.9N  112.5W ML=3.6  EMSC   WESTERN MONTANA

O: 06JUL2017 15:27:58  46.9N  112.6W Mw=3.7  EMSC   WESTERN MONTANA

O:  6JUL2017 22:24:14  46.8N  112.6W ML=3.8  EMSC   WESTERN MONTANA              

P: 12JUL2017 108977    46.7N  112.1W 2.0-4.2 CAAAA  Montana/Idaho              

 

The strongest earthquake in the U.S. or Canada since last report was an M 4.0 in the Rat Islands, Aleutians, Alaska. The last earthquake of larger magnitude in the Rat Islands was an M 5.0 on June 21. Forecast 108750 expected today's quake was likely within about 100 km of this epicenter around June 8.

 

O:  7JUL2017 02:49:57  52.0N  178.7E mb=4.0  EMSC   RAT ISLANDS, ALEUTIAN ISLANDS

P:  8JUL2017 108750    51.0N  179.0E 4.0-5.8 AAAAA  Rat Islands                

 

STRONG MONTANA QUAKE TRIGGERS EARTHQUAKE IN LEYTE, PHILIPPINES

 

EARTHQUAKE SUMMARY FOR JULY 5, 2017

 

A moderately strong earthquake of M 5.8 in western Montana today may have helped trigger an M 6.2 earthquake in Leyte, Central Philippines about an hour-and-a-half later. The two epicenters are separated by 103 degrees on the earth's surface. Seismic energy from large events reflects and refracts off core-mantle boundaries and is redirected to the surface where it concentrates around  103 degrees from the mainshock epicenter. A surge in seismicity in this distance zone often follows and is thought to be triggered by this energy.

 

The earthquake in Montana was a near-midnight event and may also have been triggered by earth tides which are maximized at this hour. The area often is active in summer months as water becomes more accessible but it has been some time since a large earthquake hit the area. It is possible that the Yellowstone Wyoming/Montana swarm of the past month helped set the area up for this large earthquake which is about 250 km north of that swarm.

 

The mainshock of M 5.8 was felt throughout the northwestern U.S. and southwestern Canada. States reporting light to moderate shaking included, Montana, Idaho, Washington, Utah, Wyoming, Oregon and in Canada, British Columbia, Saskatchewan and Alberta. Light shaking was reported from

up to 800 km from the epicenter at Portland and Beaverton, Bend, The Dalles, Oregon and in Washington at Walla Walla, Prescott, Valley, Metaline Falls, Chewelah, Sprague, Ione, Reardan, Ford, Cusick, Koon Lake, Endicott, Clayton, Medical Lake, Nine Mile Falls, Usk, Fairchile AFB, Deer Park, Cheney, Airway Heights, Spokane, Saint John, Newport, Colbert, Elk, Chattaroy, Clarkston, Colfax, Mead, Valleyford, Veradale, Otis Orchards, Newman Lakes, Fairfield, Pullman, Rockford, Uniontown, Twisp, Wenatchee, Quincy, Omak, Okanogan, Richland, Moses Lake, Keller, Incheliun, Kettle Falls, Prescott, Addy, Colville, Seattle, Lynnwood, Marysville, Auburn, Everett, Bellevue, Shelton, Port Townsend, Brush Prairie, and Yelm. 

 

In Montana the mainshock was felt with intensity VI in Canyon Creek and Lincoln, Montana with possible light to moderate damage in the epicentral area about 25-30 km from these communities. Intensity IV-V in Montana included reports from Garrison, Helena, Augusta, Deer Lodge, Ovando, Clancy, East Helena, Bonner, Drummond, Cascade, Boulder, Winston, Anaconda, Seeley Lake, Clinton, Fairfield, Philipsburg, Fort Shaw, Sun River, Missoula, Butte, Townsend, Condon, Vaughn, Choteau, Great Falls, Stockett, Arlee, Stevensville, Power, Divide, Saint Ignatius, Great Falls, Corvallis, Florence, Black Eagle, San Coulee, Frenchtown, White Sulphur Springs, Malmstrom AFB, Dutton, Three Fors, Ronan, Lolo, Victor, Belt, Dixton, Hamilton, Floweree, Bigfork, Wisdom, Huson, Raynesford, Belgrade, Manhattan, Polson, Valier, Highwood, Big Arm, Sheridan, Conner, Dayton, Rollins, Darby, Lakeside, Plains, Kila, Gallatin Gateway, Virginia City, Chester, and within about 200 km of the epicenter. Intensity II-III in Montana was reported from areas up to 350 km from the epicenter including at Billings, Winnett, Joliet, Troy, Roundup, Park City, Creston, Cranbrook.

 

In Utah it was felt with intensity II-IV in Salt Lake City, and in Idaho at Twin Falls, Preston, Kuna, Meridian, Boise, Gooding, Eagle, Garden City, Fairfield, Garden Valley, Hailey, Arco, Ketchum, Bonners Ferry, Donnelly, Priest River, Oldtown, Blanchard, Rexburg, Spirit Lake, Rathdrum, Post Falls, Sandpoint, Lewiston, Moore, Worley, Sagle, Moscow, Genesee, Potlatch, Coeur D;Alene, Athol, Tensed, Harrison, McCall, Hayden, Saint Anthony, Clark Fork, Saint Maries, Challis, Kendrick, Deary, Kingston, Grangeville, Pinehurst, Nezperce, Island Park, Smelterville, Kellogg, Kamiah, Weippe, Leadore, Mullan, Kooskia, Pierce, Wallace, Orofino, Elk City, Salmon, Carmen, and within about 400 km of the epicenter. It was also reported felt in Wyoming in Yellowstone National Park, Dubois, among others.

 

Canada felt the earthquake with intensity II-III with reports from British Columbia at White Rock, Kamloops, Kelowna, Lumby, Golden, Cranbrook, Penticton, Grand Forks, Chilliwack, Castlegar, Trail, Nelson,  and Walnut Grove up to 800 km from the epicenter. It was also felt in Saskatoon, Saskatchewan; in Alberta at Beaumont, Drumheller, Calgary, Chestermere, Brooks, Medicine Hat, Claresholn, Bow Island, Fort MacLeod, Coalhurst, Coaldale, Lethbridge, Magrath, Cardston. 

 

NEIC reported a number of moderate aftershocks of M 3.9-5.0 in the first several hours after the mainshock in Montana. These were reported felt with intensity II-III within about 150 km of the epicenters, in Montana at Helena, Great Falls, Missoula, Hamilton, Kalispell, Polson, Whitefish, and in Idaho at Wallace, Coeur D'Alene, Post Falls and Boise among others. A foreshock of M 2.3 also occurred at the epicenter of the mainshock about a day earlier. There were no obvious triggers to the foreshock that would have immediately put the area on alert for a larger event.

 

The last earthquake with M>=5.8 in western Montana within about 250 km of today's event occurred on  October  28, 1983 with M 7.3 near Challis, Idaho; in Yellowstone as M 6.1 on June 30, 1975 and as the Hebgen Lake earthquake of August 18, 1959 of M 7.7. A series of earthquake within about 50 km of today's

epicenters hit the area in October, 1935 with maximum magnitude M 6.3 on October 19, 1935 and October 31, 1935. These followed an M 5.9 foreshock on October 12, 1935. Given this regional history it appears likely that strong or moderately strong aftershocks of today's event are likely in the next two weeks. This summary had noted the damage from these earthquakes 82 years ago as:

 

"The main earthquake in a series of earthquakes in Montana in 1935. Two were killed by falling bricks. Damage estimated at $3 million. 300 buildings were damaged and up to 200 chimneys were destroyed. Severe damage at Helena at the High School, City Hall, Kessler Brewery and St. Joseph's Orphanage. Tombstones twisted and overturned. Ground cracks were common especially in allugial material where water flowed from the cracks. Changes in water flow in wells and springs occurred." (October 19, 2016)

 

The only other event of M>=5.8 within about 100 km of today's event that has been recorded occurred on June 28, 1925 with M 6.8 about 100 km southeast of today's epicenter. The historical account in this summary of this event read:

 

"This earthquake occurred east of Helena, Montana with violent shaking over 600 square miles over a felt area of about 300,000 square miles with intensity

VIII. The greatest damage occurred at Manhattan where a large schoolhouse was destroyed. Some reinforced concrete buildings survived. Many chimneys fell in all directions. Rockfalls and landslides destroyed sections of railroad track. At Three Forks similar damage was observed. A church with high unsecured walls was strongly damaged. Cracks appeared in Masonry building however frame buildings were relatively undamaged. Cracks formed in the roads. Felt throughout Montana, North Dakota, Washington and Wyoming." (June 28, 2017)

 

Water is important in promotion of seismicity in this region and the concentration of many of the important regional historical events towards the end of June or in early July is probably not coincidental but may be related to regional weather patterns. While regional earthquake activity is expected to be promoted, it is also likely that changes in groundwater and wells will be noted in the next several days as occurred in 1935.

 

Forecasts 108713 had expected a moderate earthquake in this area was likely in early July.

 

 

O: 06JUL2017 07:31:49  46.9N  112.4W ML=3.9  EMSC   WESTERN MONTANA

O: 05JUL2017 11:26:31  46.9N  112.5W ML=2.3  EMSC   WESTERN MONTANA

O: 06JUL2017 06:48:44  46.9N  112.5W ML=3.1  EMSC   WESTERN MONTANA

O: 06JUL2017 06:54:57  46.9N  112.5W ML=3.5  EMSC   WESTERN MONTANA

O: 06JUL2017 06:59:10  46.9N  112.5W ML=3.8  EMSC   WESTERN MONTANA

O: 06JUL2017 07:08:59  46.9N  112.5W ML=3.9  EMSC   WESTERN MONTANA

O: 06JUL2017 07:02:28  46.9N  112.5W Mw=4.5  EMSC   WESTERN MONTANA

O: 06JUL2017 07:11:58  46.9N  112.6W ML=3.5  EMSC   WESTERN MONTANA

O: 06JUL2017 06:35:36  46.9N  112.7W Mw=4.9  EMSC   WESTERN MONTANA

O: 06JUL2017 06:30:16  47.0N  112.4W Mw=5.8  EMSC   WESTERN MONTANA

O: 06JUL2017 07:27:29  47.0N  112.5W mb=4.4  EMSC   WESTERN MONTANA

O:  6JUL2017 06:30:16  47.0N  112.4W Mw=5.8  EMSC   WESTERN MONTANA              

O: 06JUL2017 06:30:17  46.9N  112.6W mw=5.8  ANSS   SSE of Lincoln Montana

P:  1JUL2017 108713    47.5N  115.8W 2.0-4.0 BACAA  Montana/Idaho              

 

Initial reports from the Philippines are that major damage (intensity IX) occurred in the Eastern Visayas at Naghalin and Ormos. NEIC also reported intensity VI in Jaro. Lesser shaking of intensity V occurred in Gigmoto, Bicol; and Borongan with IV in Cotcot, San Antonio, Liloan, Central Visayas, Balamban, Calero, Jaclupan, Talisay, and within about 200 km of the epicenter. Intensity II-III was reported by NEIC from Jomalig, Southern Tagalog; Iloilo, Nabitasan, Bacolod, Imbang, Brasilisa, Refugio, Naalad, Naga, Toledo, Dapitan, Cebu, Mandawa, Mandaue, Lapu-lapu, Consolacion, Okoy, Silanga, Lawaan and Pawing, Eastern Visayas and within about 300 km of the epicenter.

 

PHIVOLCS reported it was felt with intensity VII in Ormoc City and Kanaga, Leyte; VI in Jaro and Capoocan, Leyte; V in Palo, Leyte; Tacloban City; Cebu City; Mandaue City; IV in Catbalogan City; Cabucgayan and Naval, Biliran; Tolosa and Bato, Leyte, Hinunangan, Southern Leyte Sagay City, Negros Occidental; Burgos, Surigao del Norte; Biliran, Leyte; III in Bogo City and Talisay, Cebu; Roxas City; Iloilo City, Bacolod City; Inopacan, and Baybay, Leyte, Sogod, Southern Leyte, Calatrava, Negros Occidental, Tagbilaran City, Jagna, Bohol, Borongan, Eastern Samar, Guilhulngan City and Tayasan, Negros Oriental; Cadiz City and Toboso, Escalante, Negros Occidental; II in Libjo, San Jose, Cagdianao, Dinagat Islands; Sorsogon City; Lapu-lapu City, San Juan, Southern Leyte, Javier, Leyte, Tanjay City and Sibulan, Negros Oriental, Sorsogon City, Dumaguete City and I in La Carlota City, Negros Occidental; Catarman, Northern Samar.

 

This earthquake may also have been promoted by an M1.3 class solar flare of July 3, 2017 which occurred at local solar midnight and by a C-Class solar flare which occurred one day earlier at local solar noon in the epicentral area which was near sub-solar at the time of those flares. The M-class flare was the first M-class event since an M5.8 on April 3, 2017 more than three years ago while the last C-class event occurred a month ago on June 7 with C1.2. The parameters of the recent flares follow:

 

 

Flare #    START  MAX       END    CLASS     DATE    Flux (Jm-2)

 

7650       1537   1615      1618   M1.3      (July 3, 2017)   4.3E-03      

7710       0405   0425      0444   C1.1      (July 4, 2017)   2.0E-03      

 

 

Tidal effects from the previous new moon and the upcoming full moon may also have been promotional factor as noted in this summary:

 

"The full moon will arrive at 04:07 UT on July 9, 2017. Longitudinal zones which are sub-solar at this time lie near 120 degrees East longitude and 60 degrees west longitude and include area of Japan, the Philippines and Indonesia in the east and the Caribbean and South America in the West. These are the most likely area to see strong tidal triggering with this full moon, and some of this may have already begun. Tidal triggering is not limited to these area, however,  as many regions respond with promoted seismic activity around full and new moons." (July 5, 2017)

 

The timing of this Philippines event may also have been affected by stresses from TS Nanmadol which passed north of this epicenter on July 2. As the first major storm in the area this season stresses would have been strongly  seismic-promotive as noted in this summary in previous issues:

 

 

"Tropical Depression Nanmadol (05W) formed east of Taiwan (20N 124E) with winds up to 40 kts. It is expected to track west of the Ryukyu Island and over northern Honshu, Japan over the next week. The location of the eye could reduce normal friction along the Japanese subduction zone making a strong earthquake in the area likely at this time. This is the first storm of the new typhoon season, and while not large, it  could have seismic triggering potential for the area. Japan is under a seismic watch through July 6." (July 2, 2017)

 

A new storm is forming over this location at this time. The eye is currently at 21N 125E with winds up to 25 kts. But no warnings are currently in effect for the Philippines of for Taiwan until this storm intensifies.

 

The last earthquake in the Leyte area of the Philippines within about 300 km of this epicenter and with M>=6.5 occurred on February 10, 2017 about 250 km southeast of today's epicenter and prior to that on October 15, 2013 (M 7.1)  about 250 km southwest of this epicenter. The last in Leyte was an M 7.1 on June 11, 1995 about 200 km northeast of this epicenter.  Forecast 108525 had expected this earthquake within about 100 km of this epicenter was likely around June 6.

 

O: 06JUL2017 08:03:53  11.1N  124.7E MS=6.5  PHI  Felt with intensity VII

O: 06JUL2017 08:03:57  11.1N  124.6E mw=6.5  ANSS   NNE of Masarayao Philippines

O:  6JUL2017 08:03:58  11.1N  124.8E Mw=6.5  EMSC   LEYTE, PHILIPPINES           

P:  6JUL2017 108616    10.0N  125.0E 3.5-5.1 ABAAA  Luzon, Philippines         

P:  6JUL2017 108616    12.0N  122.0E 3.5-5.0 AACAA  Luzon, Philippines         

 

Tropical Storm Nanmadol may have also triggered another event off the coast of Honshu, Japan today. This earthquake of M 5.1 occurred as the remnants of Nanmadol were passing over the epicenter.  This is the strongest earthquake  within about 150 km of this epicenter, which is far off to sea, perhaps event an outer rise event, during the current year, 2017. The last of larger size this far out to sea was an M 5.3 on June 10, 2016. Forecasts 108691 had expected this event  was likely within about 50 km of the epicenter around July 4.

 

O:  6JUL2017 06:42:24  38.3N  143.5E mb=5.1  EMSC   OFF EAST COAST OF HONSHU, JAPA

P:  4JUL2017 108691    38.0N  143.0E 4.0-5.4 AAAAA  So. of Honshu              

 

MODERATELY STRONG QUAKE IN BIOBIO, CHILE

 

EARTHQUAKE SUMMARY FOR JULY 4, 2017

 

The strongest earthquake in the world today was an M 5.9 which shock Central Chile in the area from Santiago to Valparaiso, Chile. NEIC reported it was felt with intensity IV in Concepcion, Biobio, Chile and II-III in Valparaiso, Santiago, Quilpue and Vina del Mar, Chile. CSN reported this earthquake was felt with intensity  IV in  Constitucion, Chiguayante, Chillan, Concepcion, Coronel, San Carlos, San Pedro de la Paz, Talcahuano; III Cauquenes, Pelluhue, Bulnes; II Cobquecura. Felt in Maule and BioBio, Chile. No major damage was reported with earthquake. This is the largest earthquake within about 150 km of this center since an M 5.9 on November 8, 2016 which followed an M 6.4 about 300 km northeast of this on November 4, 2016 but the last of significantly larger magnitude in this 150 km area was an M 6.4 two years ago on June 20, 2015.  Forecast 108807 had expected this event within about 50 km of the epicenter was

likely around July 3.

 

O: 04JUL2017 16:05:58  35.5S   73.4W mw=5.9  ANSS   BioBio, Chile

O:  4JUL2017 16:05:58  35.5S   73.2W Mw=5.9  EMSC   OFFSHORE MAULE, CHILE        

O:  4JUL2017 16:05     35.6S   73.9W mb=5.8  GUC    Constitucion, Chiguayante, Chi

P:  3JUL2017 108807    36.0S   73.0W 4.0-5.6 AAAAA  Central Chile              

 

The earthquake swarm continued in Macedonia today. The largest in today's earthquakes was an M 4.1 which NEIC reported was felt with intensity IV in Ohrid and Struga, Macedonia. An M 5.0 yesterday has been the strongest in this series to date. Forecast 108728 had expected this activity in early July.

 

O:  4JUL2017 22:05:15  41.2N   20.9E mb=4.1  EMSC   FYR OF MACEDONIA             

P:  2JUL2017 108728    40.0N   23.0E 3.0-5.3 ABBAA  Romania/NW Turkey          

 

The strongest aftershock to date of the M 6.5 of April 3, 2017 in Botswana occurred today with M 4.9. NEIC reported it was felt with intensity II-III in Letlhakane, Boteti and Baborone, Botswana and in North West South Africa at Zeerust. The last moderate aftershock in the area occurred with M 4.6 on April 8 with the largest aftershock an M 5.0 on April 5, 2017. Forecast 108793 had expected a moderate regional event was likely around July 2.

 

O: 04JUL2017 11:37:05  22.6S   25.1E mb=4.9  ANSS   SSW of Letlhakane Botswana

O:  4JUL2017 11:37:04  22.6S   25.1E mb=4.9  EMSC   BOTSWANA                     

P:  2JUL2017 108793    26.0S   28.0E 3.0-4.6 ACBAA  Rep. South Africa          

 

The strongest earthquake in California today was an M 3.2 in the Frazier Park area northwest of Los Angeles. After the Northridge quake of January, 1994 many geoscientists thought this was the location of the next big regional earthquake. As this is the 23rd year in the 23-year cycle of large earthquakes in this area, it is of note that this earthquake occurred. Historically, much of the strong seismicity in this region occurs in late June to July, possibly triggered by weather patterns and landfall of hurricanes. The last earthquake of M>=3.2 within about 50 km of this epicenter occurred on May 30, 2017 with M 3.5 and prior to that as an M 4.1 more than a year ago on March 12, 2016. Forecast 108686 had expected this event within about 25 km of the epicenter was likely in early July.

 

NEIC reported this earthquake of M 3.2 in Southern California was felt with intensity IV in Bakersfield and II-III in the area(s) of Frazier Park, Lebec, Castaic, Tehachapi, Valencia, Granada Hills and Los Angeles, California.

 

O:  4JUL2017 13:42:09  34.9N  119.0W ML=3.2  EMSC   CENTRAL CALIFORNIA           

O: 04JUL2017 13:42:09  34.9N  119.0W ml=3.2  ANSS   Frazier Park CA

P:  9JUL2017 108686    35.0N  119.2W 2.5-4.6 BAAAA  So. California             

 

The largest earthquake in the U.S. or Canada today occurred in the central Andreanof Islands with M 4.0. It was not felt in this remote epicentral area. This area of the western Aleutians, Alaska has been active in the past two weeks. The last event of M>=4.0 in the region within about 100 km of this epicenter occurred on July 1, 2017 with M 4.2. Forecast 108738 expected this event around July 2.

 

O:  5JUL2017 00:36:47  51.2N  177.1W ML=4.0  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P:  2JUL2017 108738    51.7N  178.5W 3.5-5.0 BAAAA  Andreanoff Isls, Aleutians 

 

 

MODERATE EARTHQUAKE IN MACEDONIA PART OF A MAJOR SWARM

 

EARTHQUAKE SUMMARY FOR JULY 3, 2017

 

An earthquake of M 4.8-5.0 in Macedonia today was widely felt with intensity up to V in the epicentral area. A series of felt foreshocks and aftershocks accompanied this event. NEIC reported the mainshock was felt with intensity V in Macedonia at Ohrid and IV in Kosel, Struga, Bitola, and II-III in Lukovo, Prilep, Gramsh, Caska, Struga, Veles, Sopiste, Skopje, and in Albania at Vore, Tirana, Pogradec. It was also felt with intensity II in Pristina, Kosovo and Methohija, Servia and Montenegro and in Sofia, Bulgaria. In response to a foreshock one responder to the EMSC website said he knew what was causing the earthquakes - the sealing of the local volcano was trapping the winds below the earth and causing the quakes. An ancient explanation (Socrates or Aristotle) to a modern problem.

 

The strongest aftershock was an M 4.2. Minor damage was reported in the epicentral area in Macedonia. The only prior event in Macedonia this year with M>=4 occurred on May 14 with an M 4.2 about 100 km north of today's epicenter. The last earthquake within about 150 km of this epicenter in Macedonia of M>=5.0 occurred on September 11, 2016 with M 5.3 and December 29, 2014 (M 5.0).

 

Forecasts 108472 and 108670 had expected this activity was likely at the end of June or in early July. 

 

O:  3JUL2017 18:03:24  41.1N   20.9E mb=4.2  EMSC   FYR OF MACEDONIA             

O:  3JUL2017 11:18:20  41.2N   20.9E mb=5.0  EMSC   FYR OF MACEDONIA              

P:  8JUL2017 108670    39.0N   20.0E 3.0-5.0 BCAAA  No. Greece                 

P: 26JUN2017 108472    40.0N   21.0E 3.0-5.3 CAAAA  Romania/NW Turkey          

 

An earthquake of M 4.5 continued the series of events in the Ryukyu Islands

of southwestern Japan today. Forecast 108641 had expected this event within about 100 km of the epicenter was likely around July 2. It was probably promoted by stresses from Tropical Storm Nanmadol which was centered over this epicenter at the time of the earthquake. This summary had expected this activity in the previous issue as:

 

"Tropical Storm Nanmadol (05W) continued west of the Ryukyu Islands with winds up to 75 kts. It is expected to track west of the Ryukyu Island and over northern Honshu, Japan over the next week. The location of the eye could reduce normal friction along the Japanese subduction zone making a strong earthquake in the area likely at this time. This is the first storm of the new typhoon season, and while not large, it  could have seismic triggering potential for the area. Japan is under a seismic watch through July 6." (July 3, 2017)

 

O:  3JUL2017 17:23:30  27.1N  127.3E mb=4.5  EMSC   RYUKYU ISLANDS, JAPAN        

P:  2JUL2017 108641    28.0N  127.0E 4.0-5.5 AAAAA  Ryukyu Islands              

 

The strongest earthquake in the world today was an M 5.4 in the Solomon Islands. It was not reported felt in this area. The last earthquake within about 150 km of this epicenter with M>=5.4 occurred to the west on May 29 with M 5.4 an aftershock of the M 5.8 of May 24, 2017. Today's earthquake was not reported felt in the epicentral area. Forecast 108787 had expected this event was likely around July 2 within about 100 km of the epicenter.

 

O:  4JUL2017 00:37:17  11.3S  163.0E mb=5.4  EMSC   SOLOMON ISLANDS              

P:  2JUL2017 108787    11.0S  162.0E 4.0-5.6 AAAAA  Vanuatu Islands            

 

MODERATELY STRONG QUAKES CONTINUE IN KERMADEC ISLANDS, NEW ZEALAND

 

EARTHQUAKE SUMMARY FOR JULY 2, 2017

 

Moderately strong earthquakes continued in the Kermadec Islands today with events of M 5.8 and 5.5 in the northern Kermadecs of New Zealand. This continues strong activity in the region of the past two weeks beginning with an M 5.9 on June 15 and including two earthquakes of M 6.0 on June 28 and 29, 2017. As the only permanent settlements in the area are research facilities on Raoul Island, this activity has not been reported felt. Today's earthquakes are not aftershocks of the earlier events in June as they are occurring 300-400 km northeast of those epicenter. The last earthquake of M>=5.8 within about 150 km of today's epicenters occurred July 13, 2016 with M 6.3 and prior to that on August 9, 2015. Earthquakes in  this region in recent years have concentrated in the months of July and August and may be promoted by regional weather patterns. Forecast 108801 had expected this activity within about 100 km of these epicenters around July 1.

 

O:  2JUL2017 12:40:04  27.5S  176.0W Mw=5.5  EMSC   KERMADEC ISLANDS REGION      

O:  2JUL2017 09:58:50  27.5S  176.4W Mw=5.8  EMSC   KERMADEC ISLANDS REGION      

P:  1JUL2017 108801    27.0S  177.0W 4.0-5.8 AAAAA  Tonga Islands              

 

NEIC reported an unusual earthquake of M 1.5 occurred early in the morning on July 2 in the region of Gray and New Gloucester, Maine. It was too light to have been felt in the area but is the first of any magnitude recorded in the New Gloucester, Maine region since a similar M 1.5 on October 14, 2016. The last of larger magnitude in the area was an M 1.9 on January 16, 2014. The last event of M>2 in the area  was an M 2.2 on December 11, 2007. Earthquakes of M 1.7 each hit the area on March 30, 2013 and January 25, 2008. Forecast 108454 had expected this event within about 25 km of the epicenter was likely around June 30.

 

O:  2JUL2017 06:08:13  43.9N   70.3W ml=1.5  ANSS   New Gloucester Maine          

P: 30JUN2017 108454    44.0N   70.0W 2.0-4.1 AAAAA  Maine                      

 

The strongest earthquake in the U.S. or Canada today was an M 3.6 in the Kenai Peninsula, Alaska. The last earthquake within about 100 km of this epicenter with M>=3.6 occurred on May 7, 2017 with M 3.6 and prior to that as an M 3.5 on January 24, 2017. The last of larger magnitude was an M 4.4 on November 30, 2016. Forecast 108758 had expected this event within about 100 km of this epicenter around July 3.

 

NEIC reported this earthquake of M 3.6 in Southern Alaska was felt with intensity II-III in the area(s) of Anchorage and Girdwood, Alaska.

 

O:  2JUL2017 22:37:35  60.9N  151.8W ML=3.6  EMSC   KENAI PENINSULA, ALASKA      

P:  3JUL2017 108758    60.1N  150.6W 3.2-5.1 AAAAA  Central Alaska             

 

A swarm of earthquakes occurred in the Puerto Rico Trench north of that Island. The largest of this group which included nine events of M>=3 was and M 3.4. Much of today's activity centered around local solar noon and may have been promoted by tidal stresses. But the area is overdue for a  major earthquake and tsunami and this portion of the trench is the most likely point for rupture initiation of such an event. The last event of M>3.4 in Puerto Rico was recorded on March 40 with M 4.3. The last of M 3.4 was an  M 3.4 on May 26, 2017.

 

O:  2JUL2017 15:36:14  19.0N   65.3W MD=3.0  EMSC   PUERTO RICO REGION           

O:  2JUL2017 21:39:43  19.0N   65.3W MD=3.2  EMSC   PUERTO RICO REGION            

O:  2JUL2017 16:39:27  19.1N   65.3W MD=3.2  EMSC   PUERTO RICO REGION           

O:  2JUL2017 17:36:13  19.1N   65.3W MD=3.2  EMSC   PUERTO RICO REGION           

O:  2JUL2017 17:13:30  19.1N   65.3W MD=3.4  EMSC   PUERTO RICO REGION           

O:  2JUL2017 15:06:45  19.1N   65.4W MD=3.1  EMSC   PUERTO RICO REGION           

O:  2JUL2017 15:25:18  19.1N   65.4W Md=3.3  EMSC   PUERTO RICO REGION           

O:  2JUL2017 15:17:10  19.2N   65.4W MD=3.0  EMSC   PUERTO RICO REGION           

O:  2JUL2017 15:32:18  19.2N   65.4W MD=3.1  EMSC   PUERTO RICO REGION           

P:  4JUL2017 108626    19.0N   66.0W 3.4-5.3 AAAAA  Puerto Rico                

 

 

LIGHT QUAKES SHAKE ILLINOIS AND SWITZERLAND

 

EARTHQUAKE SUMMARY FOR JULY 1, 2017

 

Global seismicity today prepared for the next round of strong events. Unusual earthquakes were felt in Switzerland (M 4.1-4.3) and Illinois (M 3.1). The strongest earthquake of the day was an M 5.2 in Hokkaido, Japan, possibly related to the M 5.8 event in the Kuril Islands yesterday. Like that event, today's earthquake which was felt in Hokkaido was located at 104 degrees from the two Guatemala quakes of June 14 and 22 of M 6.8-7.0 and was possibly promoted from that source. A new Tropical Storm formed east of Taiwan. This summary issued the following notice:

 

"Tropical Depression Nanmadol (05W) formed east of Taiwan with winds up to 40 kts. It is expected to track west of the Ryukyu Island and over northern Honshu, Japan over the next week. The location of the eye could reduce normal friction along the Japanese subduction zone making a strong earthquake in the area likely at this time. This is the first storm of the new typhoon season, and while not large, it  could have seismic triggering potential for the area. Japan is under a seismic watch through July 6." (July 1, 2017)

 

The last earthquake in Hokkaido of larger magnitude than M 5.2 occurred April 30 with M 5.3. The only event during 2017 in Hokkaido of significantly larger magnitude was an M 5.7 on March 7. Forecast 108706 had expected this earthquake in early July.

 

NEIC reported this earthquake of M 5.2 in Hokkaido, Japan was felt with intensity II-III in the area(s) of Hokkaido at Katahiroshima, Otaru,  Sahikawa and Hakodate, Hokkaido, Japan.

 

O:  1JUL2017 14:45:54  42.8N  141.9E mb=5.2  EMSC   HOKKAIDO, JAPAN REGION       

P:  1JUL2017 108706    42.0N  143.0E 3.5-5.5 AAAAA  Hokkaido, Japan            

P:  5JUL2017 108706    43.0N  143.0E 3.5-5.6 BAAAA  Hokkaido, Japan            

 

Upcoming seismicity will also probably be promoted by minor storms due today in the geomagnetic field. Triggered seismicity is most likely at high and low latitudes around July 6-7.

 

A light earthquake of M 3.1 shook parts of Illinois today. NEIC reported it was felt with intensity II-III in Illinois at Vandalia, Mulberry Grove, Greenville, Carlyle, Pocahontas, Brownstown, Ramsey, Kinmundy, Springfield, Champaign and in Missouri at Saint Louis, Bergen. It was also reported lightly felt in Jasper, Indiana and in Dayton, Ohio. A lighter earthquake occurred in southern Illinois on June 27 (M 2.1) and on May 31 with M 2.2, but this is the strongest earthquake in Illinois during 2017. The last earthquake in Illinois or larger magnitude within about 100 km of today's epicenter occurred on May 30, 2015. The strongest event in the state in the past 25 years was an M 3.9 on June 7, 2011.

Forecast 108669 had expected an event in Illinois was likely around July 4.

 

O:  1JUL2017 18:07:32  38.9N   89.2W Mw=3.1  EMSC   ILLINOIS                     

O: 01JUL2017 18:07:32  38.8N   89.2W mw=3.1  ANSS   16km SW of Vandalia

P:  4JUL2017 108669    38.0N   89.0W 2.0-3.9 BAAAA  New Madrid area            

 

An unusual earthquake of M 4.1-4.3 was felt today throughout much of Switzerland. NEIC reported maximum intensity VI near Montbovon, Freiburg and V in Rossiniere and Monthey, Waadt and Bulle, Freiburg. It was also reported felt with intensity II-III in France at Annecy, Rhone-Alpes and in Switzealand within about 100 km of the epicenter at Solothurn, Carouge, Les Bois, Fribourg, Le Mont-sir-Lausanne, Pully, udex, Ollon, Port-Valais, Saanen, Vevey, Rueyres, Palezieus, Ormont-Dessous, Attalens, Veytaux, Blonay, La Tour-de-Treme, Chatel-Saint-Denis, Gruyeres, and Albeuve, Freiburg, Switzerland.  

While not highly seismic, the station and network in Zurich, Switzerland (ZUR and ETH) has reported earthquakes continuously for more than 100 years and is highly regarded in the geophysical community. The only earthquake in 2017 of larger magnitude in Switzerland was an M 4.6 on March 6, 2017. Forecast 108444 had expected today's event was likely to the south of this epicenter around June 29.

 

O:  1JUL2017 08:10:34  46.5N    7.1E ML=4.3  EMSC   SWITZERLAND                  

O: 01JUL2017 08:10:34  46.5N    7.0E mw=4.1  ANSS   WNW of Chateau-d'Oex Switzerland

P: 29JUN2017 108444    45.0N    8.0E 3.0-5.1 ABAAA  Austria                    

 

The strongest earthquake in the U.S. or Canada today was an M 3.9 in Central Alaska. NEIC reported this earthquake of M 3.1 in Central Alaska was felt with intensity II-III in the area(s) of Matanuska-Sustina Border, Alaska.  The last earthquake within about 100 km of this epicenter with M>=3.9 occurred on May 2, 2017 with M 4.2.  Forecast 108762 had expected this event within about 25 km of the epicenter around July 2.

 

O:  1JUL2017 16:51:52  62.2N  151.3W ML=3.9  EMSC   CENTRAL ALASKA               

O:  1JUL2017 09:48:48  62.6N  150.8W Ml=3.1  EMSC   CENTRAL ALASKA               

P:  2JUL2017 108762    62.7N  150.6W 3.2-5.1 AAAAA  Central Alaska             

 

 

 

STRONG QUAKES CONTINUE IN KERMADEC ISLANDS; NEAR NO.ATLANTIC ANTIPODE

 

EARTHQUAKE SUMMARY FOR JUNE 29, 2017

 

A second earthquake of M 6.0 occurred today in the Kermadec Islands of New Zealand. This event follows a similar earthquake yesterday about 200 km northeast of this epicenter. Today's event was not reported felt in this remote area. This is the strongest earthquake within about 200 km of this epicenter west of the international Date line since  an event of M 6.2 on February 1, 2016 and prior to that as an M 6.2 on November 22, 2009. Forecast 108558 had expected this activity was likely in late June.

 

O: 29JUN2017 07:03:09  31.1S  180.0E Mw=6.0  EMSC   KERMADEC ISLANDS REGION      

O: 29JUN2017 07:03:10  31.1S  180.0W mw=6.0  ANSS   WNW of L'Esperance Rock      

P: 23JUN2017 108558    32.0S  178.0W 4.0-5.4 CABAA  So. Kermadec Islands       

 

Near the antipode of the Kermadec Islands, an unusual earthquake of M 5.4-5.5 occurred in the North Atlantic Ocean. The largest previous earthquake during 2017 along the Atlantic Ridge was an M 5.4 near Ascension Island. This is the strongest earthquake in the mid-Northern Atlantic region within about 250 km of this epicenter since an M 5.7 on November 18, 2011. This area often is active during hurricane season and may be promoted by stresses from those storms. Forecast 108409 had expected today's event within about 150 km of this epicenter was likely around June 24. 

 

The event in the North Atlantic is located at the seventh node (51.4 degrees) from the M 6.8-7.0 quakes in Guatemala on June 14 and 22 and is likely to have been promoted by energy from those events. An event in Central Chile of M 4.8 was at the same distance from Guatemala today.

 

O: 30JUN2017 01:34:58  33.8N   38.6W Mw=5.5  EMSC   NORTHERN MID-ATLANTIC RIDGE  

P: 24JUN2017 108409    33.0N   40.0W 4.0-5.4 CAAAA  No. Mid-Atlantic Ridge     

 

An antipodal pair also occurred beginning with an M 4.6 in North Island, New Zealand and followed by an M 3.5 in Spain within about 200 km of the antipode. Antipodal pairs in these two regions are not uncommon and are probably due to free earth oscillations. The event in New Zealand had been expected in forecast 108556 to occur within about 50 km of that epicenter around June 28 while the earthquake in Spain was thought likely within about 100 km around June 25 in forecast 108401. Neither was reported felt or damaging in their respective epicentral areas.

 

O: 29JUN2017 07:06:43  39.0S  176.6E ML=4.6  EMSC   NORTH ISLAND OF NEW ZEALAND  

P: 28JUN2017 108556    39.0S  176.0E 3.0-4.5 AAAAA  North Island, N.Z.         

 

O: 29JUN2017 22:32:37  37.1N    3.9W ML=3.5  EMSC   SPAIN                        

P: 25JUN2017 108401    36.0N    4.0W 3.5-5.0 BBAAA  Morocco/Spain              

 

Thanks to P.C. in California for sending an account noting that a published article by University of Washington geoscientists shows that distant earthquakes have an effect of underwater landslides off the Northwest coast of the U.S. in some cases triggering them. This may overestimate the danger of tsunamis along the northwest coast. As she says, it is an admission long overdue. This is an effect, probably related to free earth oscillations on extremely unstable systems where landslides, like earthquakes, are on the verge and need only a small trigger to set them off. This can be provided by motion associated with free-earth oscillations. This motion is maximized at nodal distances where D=360*m/n where D is the distance in degrees and m<n are small integers.  

This summary has issued daily reports for years on these distances because they affect the likelihood of earthquakes in specific regions.

 

The strongest earthquake in the U.S. or Alaska today was an M 4.3 in the Bering Strait off western Alaska mainland.  NEIC reported this earthquake of M 4.3 in the Bering Strait, Alaska was felt with intensity II-III in the area(s) of Nome, Alaska.  This is the strongest earthquake within about 200 km of this epicenter in the Bering Strait since an M 4.5 on July 9, 2016 and prior to that an M 4.8 on May 21, 2011.

 

O: 29JUN2017 20:05:21  65.3N  168.8W ML=4.3  EMSC   BERING STRAIT                

 

Strong earthquake swarms continued in West Yellowstone, Wyoming today. This was joined by a strong swarm in the Loihi Seamount south of Hawaii which included

a number of light earthquakes including an M 3.0 and 3.3. These follow a larger

earthquake in the area earlier in June. The nature of today's swarm suggests an underwater volcanic episode is in progress in this area.

 

The event in Yellowstone had been expected within about 25 km of the epicenter around June 29. It is located at the tenth node (36 degrees) from Guatemala  and began shortly after the strong Guatemalan events of June 14 and 22 and was probably promoted from that source.

 

The activity in Hawaii had been anticipated in forecast 108338 within about 10 km of this epicenter and in this summary in the June 9, 2017 report as follows:

 

 

"The strongest earthquake in the U.S. or Canada today was an M 4.5 in Hawaii. NEIC reported this event was felt with intensity IV in Hawaii at Naalehu and Pahala and II-III in Captain Cook, Volcano, Holualoa, Kealakekua, Pahoa, Mountain View, Hilo, Kurtistown, Keaau, Paauilo, Kailua Kona, Papaikou, Ninole, Honomu, Kamuela, Waikoloa, Laupahoehoe, Ookala, Honokaa, Kapaau, Hawi, Kihei, Kahului, Honolulu, Kailua, and Kalaheo and in general within about 350 km of the epicenter. This event is located near Loihi Seamount, an area which had not seen moderate seismicity since an event of M 5.2 on June 5, 2013. A moderate earthquake of M 5.2 hit north of this near Kilauea on June 8, 2017 with M 5.3. This may have promoted the current activity. That earthquake occurred in association with the full moon and may have tidally promoted, not dissimilar to today's association with the new moon. At the time, this summary noted: (June 22, 2017)

 

"Moderate earthquakes at volcanic centers, such as today's event, can change plumbing within the volcano array leading to changes in current eruptive phases either dampening or accelerating the flow of magma. In the current situation, a pair of light earthquakes occurred in the Loihi Seamount area south of Hawaii just before the mainshock. This seamount south of Hawaii was very active about a decade ago but has been quiet for a number of years, so even light activity there, especially in association with the strange seismicity of the past several days could be notable." (June 9, 2017)

 

The activity in Hawaii is located at the sixth node (60 degrees) from the M 6.8-7.0 quakes in Guatemala on June 14 and 22 and is likely to have been promoted by energy from those events.

 

O: 29JUN2017 13:19:57  18.9N  155.3W ML=3.0  EMSC   HAWAII REGION, HAWAII        

O: 29JUN2017 16:18:15  18.9N  155.3W ML=3.2  EMSC   HAWAII REGION, HAWAII        

P: 23JUN2017 108338    18.8N  155.2W 3.0-4.6 CAAAA  Hawaii                     

 

O: 29JUN2017 02:32:07  44.8N  111.0W ML=2.0  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 29JUN2017 02:33:39  44.8N  111.0W ML=2.0  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 29JUN2017 03:20:49  44.8N  111.0W ML=2.0  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 29JUN2017 07:44:34  44.8N  111.0W ML=2.0  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 29JUN2017 03:26:17  44.8N  111.0W ML=2.1  EMSC   YELLOWSTONE NAT. PARK, WYOMING

P: 29JUN2017 108483    44.6N  110.8W 2.0-3.9 AAAAA  Yellowstone/Wyoming        

 

TONGA SEISMICITY MOVES TO THE SOUTH

 

EARTHQUAKE SUMMARY FOR JUNE 28, 2017

 

The moderately strong to strong seismicity in Tonga and Fiji over the past several days moved south into the Kermadec Islands of New Zealand today. An M 6.1 was recorded any may have been felt in North Island, New Zealand at Whangarei, Northland about 1000 km to the south of this event. This is the strongest earthquake located in the Kermadec Islands during 2017. An M 5.9 hit near this epicenter on June 15. The last earthquake in the Kermadec group with M>=6.0 occurred on July 13, 2016 with M 6.3 while the last within about 200 km of today's epicenter occurred more than a year ago as an M 6.1 on June 6, 2016 and prior to that as an M 6.3 on July 3, 2014 with M 6.3. Forecast 108542 had expected the area could see a moderate to large quake around June 29.

 

A local solar midnight earthquake, possibly triggered by high tidal stresses, occurred as an M 4.6 north of the Kermadec Islands earlier in the day. This is not an aftershock nor a foreshock to any recent events but is at an unusual epicenter south of the Fiji Islands.

 

O: 28JUN2017 18:20:52  30.4S  177.4W Mw=6.0  EMSC   KERMADEC ISLANDS, NEW ZEALAND

O: 28JUN2017 18:20:53  30.3S  177.6W mw=6.0  ANSS   Raoul Island New Zealand

P: 29JUN2017 108542    29.0S  176.0W 4.0-5.5 ABAAA  No. Kermadec Islands       

 

O: 28JUN2017 12:12:18  26.2S  178.6E mb=4.7  EMSC   SOUTH OF FIJI ISLANDS        

P: 19JUN2017 108274    24.0S  179.0E 4.0-5.5 CCAAA  Tonga/Fiji                 

 

A moderately strong earthquake also occurred today in the southern Kuril Islands with M 5.8. It was not reported felt and did not trigger a tsunami. This is  the strongest earthquake in the Kuril Islands during 2017. Events of M 5.4 and 5.5

 hit the region on April 20 and June 22 near today's epicenter. When the quake occurred on June 22 this summary noted:

 

"The strongest earthquake in the world today was an M 5.4 in the region of the Kuril Islands. This event was not reported felt in the area. It occurred near local solar noon and may have been enhanced by tidal stresses which maximize near this time. The area will be under high tidal stresses with the new moon on June 24 as noted in this summary:

 

"The new moon will arrive on June 24 at 02:31 UT. Areas which are sub-solar at this time lie within about 20 degrees longitude of 145 East longitude while those anti-solar areas are near 35 West longitude. These include the mid-Atlantic Ocean region in the west and Japan and the western Pacific subduction zone in the east. These regions are most likely to see a strong to major earthquake during the period June 22-26 but tidal enhancement of seismicity can occur in many tectonic settings and is most likely near local solar midnight and noon at this time." (June 21, 2017)

 

While normally an active zone, the Kuril Islands has been relatively quiet this year. The largest events were of M 5.4-5.5 on May 22 and April 20, 2017. The last earthquake of larger magnitude than M 5.5 in the region was an M 5.7 on July 23, 2016. The last within about 200 km of today's epicenter occurred as an M 6.2 on July 20, 2014.  Forecasts 108475 and 108450 had expected today's event within about 150 km of this epicenter was likely around June 24-25." (June 22, 2017)

 

In the distance section of this summary, an increase in seismicity in the Kuril

Islands had been expected as this area lies at 101-103 degrees from the double shocks in Guatemala of M 6.8-7.0 which occurred June 14 and 22. This is a distance at which strong seismic enhancement is often noted following strong earthquakes elsewhere in the world. Concentrated seismic energy from these quakes is  probably promoting this increase. Forecast 108475 had expected this event was likely around June 26.

 

O: 28JUN2017 12:07:30  43.8N  147.9E mb=5.8  EMSC   KURIL ISLANDS                

P: 26JUN2017 108475    45.0N  148.0E 3.5-5.5 AAAAA  So. Kurils                 

 

The strongest earthquake in the U.S. or Canada today was an M 3.9 in the eastern Andreanof Islands, Aleutians, Alaska. This event was not reported felt in this remote area. An earthquake of M 4.0 hit about 50 km west of this on June 24 an on June 5 with M 4.4. Forecast 108486 had expected a moderate earthquake in the area around June 29. 

 

O: 28JUN2017 10:58:19  52.2N  173.5W mb=3.9  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P: 29JUN2017 108486    50.7N  176.2W 3.5-5.0 ABBAA  Andreanoff Isls, Aleutians 

 

 

COMMEMORATING 25 YEARS SINCE LANDERS, CALIFORNIA EARTHQUAKE (M 7.8)

 

EARTHQUAKE SUMMARY FOR JUNE 27, 2017

 

It was a very quiet date in global seismicity today. The largest events of M 4.9 each were located in Hindu Kush, Afghanistan and in Halmahera, Indonesia. Neither of these was damaging and both were felt with light intensity. As often happens in mid-summer seismicity was on the increase in the central U.S. where light earthquakes of M 2.0-2.1 occurred in Illinois and Arkansas as well as the ongoing seismicity in Oklahoma and Kansas. The minor swarm in the Truckee area of Northern California continued at a reduced level. A second minor swarm including an M 2.5 occurred near Landers, California marking 25 years since an M 7.8 at that epicenter.

 

June 28, 2017 is the 25th anniversary of an earthquake of M 7.8 in Southern California which occurred June 28, 1992. The following excerpt from the history section of this report describes that event:

 

" 6 28 11 57 35 1992  34.190 -116.540  10 7.8   So. California

 

The largest earthquake in California in 40 years, this event killed one at Yucca Valley and two others by heart attacks. More than 400 were injured.  Considerable damage occurred to buildings (bowling alley, residences, stores) in the Landers and Yucca Valley area. The maximum intensity of this earthquake was IX. It apparently triggered a second strong event several hours later in  the Big Bear area east of Los Angeles. Estimated cost was $92 million U.S. dollars. Felt in Utah, Arizona, New Mexico, Colorado, Nevada. Surface faulting was observed in the Barstow and Joshua Tree area with more than 5 meters  horizontal displacement and up to 1.0 meters vertical displacement. Seiche was observed from Washington, Colorado and Texas." (June 28, 2016)

 

The author was working in Colorado at the time of this earthquake. Personal recollection of that Sunday? morning may be of interest to readers. It was a hot morning and sleep was fitful. About 6 o'clock I was awakened by the howling of a local dog (Ransom by name) who had made a stand outside my bedroom window. I couldn't get back to sleep because of the  incessant howling, barking and whining Ransom was making. He had never done this before in the years we had been neighbors. So eventually I got up and tried to calm him down, which seemed to work. Because of the heat and disruption I couldn't get back to sleep so I turned on the television and caught the first reports of a major earthquake in southern California. Surface waves from this event would have arrived about the time Ransom started his outburst and major seiche was observed in the area where I was living. I speculate Ransom felt the local effects and was frightened having not felt this before, and needed to tell the world about it, and my bedroom was right next door. It was at the time when automatic web data was just beginning. Initial locations gave the location near Baker, California, a small hamlet in the California Desert which few had ever heard of. But at first, the quake was known as the Baker quake only later to be designated as the Landers earthquake after a somewhat larger town near the epicenter. We used to kid James Lander, founder of the National Earthquake Information Center (NEIC) that he finally had an earthquake named after him (this was not the case but the kidding was in fun anyway).

 

A minor swarm of earthquakes occurred today in the Yucca Valley/Landers area within about 10 km of the epicenter of June 28, 1992 event. The largest of these was M 2.5 within about 10 km of the epicenter of the 1992 event but was not

felt in this remote area. The area experienced a long period of quiet following the M 7.8 in 1992. The last earthquake of M>=2.5 within about 20 km of the  1992 mainshock occurred as an M 3.0 on April 7, 2017 and prior to that an M 3.5 on June 16, 2016 and an M 2.7 on August 3, 2015, the only three such earthquakes  in the past two years in the area. Statistically stronger aftershocks tend to occur about the same time of year, probably due to climate effects. The largest aftershock since 2000 was the M 3.5 in 2016. Forecast 108422 had expected this activity was likely at the end of June.

 

 

O: 27JUN2017 01:00:16  34.3N  116.4W ml=2.0  ANSS   Yucca Valley CA

O: 27JUN2017 01:24:43  34.3N  116.4W ml=2.5  ANSS   Yucca Valley CA

O: 28JUN2017 00:34:13  34.3N  116.5W ml=2.1  ANSS   Yucca Valley CA

O: 28JUN2017 00:34:13  34.3N  116.5W ML=2.1  EMSC   SOUTHERN CALIFORNIA          

P: 23JUN2017 108422    34.3N  116.5W 2.5-4.6 BAAAA  So. California             

 

The strongest earthquake in the U.S. or Canada today occurred within about 45 minutes of local solar noon in the Fox Islands, Aleutians, Alaska with M 4.0. This event was not reported felt. An M 5.8 hit near this epicenter on May 24 and this is probably an aftershock of that earthquake. Forecast 108489 had  expected today's event was likely around June 28.

 

O: 27JUN2017 23:45:26  53.2N  166.7W ML=4.0  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

P: 28JUN2017 108489    52.5N  166.5W 3.5-4.9 AAAAA  Fox Islands, Aleutians     

 

 

MODERATELY STRONG NOON QUAKE HITS FIJI

 

EARTHQUAKE SUMMARY FOR JUNE 26, 2017

 

An earthquake pair of M 5.3 and M 5.8 hit the region of Fiji today within minutes of local solar noon. These are probably tidally promoted seismicity as high tidal stresses occur at local noon and midnight. These are not aftershock of the M 6.2 in Fiji yesterday as they occurred about 500 km south of that epicenter. They were not reported felt in the remote epicentral area. The last earthquake with M>=5.8 within about 250 km of these epicenters was an M 6.1 on June 17, 2017 and these are probably aftershocks of that event. An M 6.9 occurred on February 24, 2017. Forecast 108549 had expected this activity within about 100 km of these epicenters was likely around June 27.

 

O: 27JUN2017 00:14:34  24.8S  177.3W mb=5.3  EMSC   SOUTH OF FIJI ISLANDS        

O: 27JUN2017 00:14:34  24.8S  177.3W mb=5.3  ANSS   the Fiji Islands

O: 27JUN2017 00:14:38  24.6S  177.0W Mw=5.8  EMSC   SOUTH OF FIJI ISLANDS

P: 27JUN2017 108549    25.0S  176.0W 4.0-5.7 AAAAA  Tonga Islands              

 

The strongest earthquakes in the U.S. or Canada today occurred along the northern border of California and Nevada with M 4.0 and 4.1. These were part of a strong swarm in the region which occurred within an hour of local solar midnight and may have been promoted by high tidal stresses which maximize at this hour. NEIC reported maximum intensity V in Truckee, California and IV in Norden, Dutch Flat, Glenbrook, California. Lesser shaking with intensity II-III was reported felt up to 140 km from the epicenter in Sacramento as well as in Sierraville, Soda Springs, Loyalton, Carnelian Bay, Kings Beach, Tahoe Vista, Tahoe City, Incline Village, Alta, Tahoma, Forest Hill, Nevada City, Grass Valley, Colfax, Georgetown, South Lake Tahoe, Rough and Ready, Pollock Pines, Quincy, Applegate, Meadow Vista, Garden Valley, Penn Valley, Cook, Camino, Lotus, Placerville, Newcastle, Somerset, Rescue, Pioneer, Lincoln, El Dorado Hills, Rocklin, Granite Bay, Shingle Springs, Folsom, Orangevale, Fair Oaks, Yuba City, Rancho Cordova, Chico, and in Nevada at Reno, Glenbrook, Sparks, Gardnerville.

 

No major damage was reported. The last earthquake within about 50 km of these epicenters with M>=4.1 occurred on October 27, 2011 with M 4.7-4.9 and prior to that on December 25, 2008 with M 4.5. Forecast 108391 had expected this activity was likely around June 29 about 30 km northwest of these epicenters.

 

O: 27JUN2017 09:04:47  39.5N  120.4W ML=2.9  EMSC   NORTHERN CALIFORNIA

O: 27JUN2017 09:16:28  39.5N  120.4W ML=2.9  EMSC   NORTHERN CALIFORNIA

O: 27JUN2017 09:02:01  39.5N  120.4W ML=4.0  EMSC   NORTHERN CALIFORNIA

O: 27JUN2017 09:09:21  39.5N  120.4W ML=4.1  EMSC   NORTHERN CALIFORNIA

O: 27JUN2017 09:36:29  39.5N  120.3W ML=2.1  EMSC   NORTHERN CALIFORNIA          

P: 29JUN2017 108391    39.8N  120.6W 2.5-4.4 AAAAA  Central California