MODERATELY STRONG QUAKE SOUTH OF AUSTRALIA

 

EARTHQUAKE SUMMARY FOR APRIL 21, 2018

 

The largest earthquake of the day was an M 5.8 on the Western Indian-Antarctic Ridge south of Australia. It was not reported felt in this remote area. It occurred within about 30 minutes of local solar midnight and may have been promoted from the geomagnetic storm and tidal effects which maximized near this hour. The high latitude (near Antarctica) suggests the geomagnetic storm was a major promoter of this event. This is the strongest earthquake within about 300 km of this epicenter since an M 5.9 on December 13, 2008, the only such event in the region with M>=5.8 in the past 25 years.  Forecasts 116090 and 116375 had expected this event within about 100 km of the epicenter between April 18 and 25. The antipode of this earthquake is in eastern Quebec at 49N 58W, an area where low-level seismicity occurs and may be promoted by energy concentrations from the Indian-Antarctic event today.

 

O: 21APR2018 19:44:20  49.1S  123.5E Mw=5.8  EMSC   WESTERN INDIAN-ANTARCTIC RIDGE

P: 18APR2018 116090    49.0S  122.0E 4.0-5.6 BAAAA  So. of Australia           

P: 25APR2018 116375    49.0S  122.0E 4.0-5.5 BAAAA  So. of Australia           

 

Seismicity in Hawaii was up today in concurrence with the geomagnetic storm which probably helped promote it. Two earthquakes of M>=3 were recorded in the region, an M of M 3.0 and 3.1 and were felt lightly in Hawaii at Kula, Wailuku and Lahaina. The largest of these of M 3.1 occurred within about an hour of local solar midnight and may also have been promoted by tidal stresses. Geomagnetic effects had been anticipated in this summary in previous issues as:

 

 

"The geomagnetic field saw minor storm conditions today. The AP level was 47. High latitude geomagnetic field was also stormy with AP at 56. KP levels at high latitude reached 7 mid-day on April 20. It is likely this was triggered by an undetected CME from the sun. This is the most active the geomagnetic field has been since it reached AP 47 on November 8, 2017 with high latitude AP 82. This could launch a new round of increased seismicity beginning April 21 with most likely strong quakes near the geomagnetic equator and at high latitudes around April 24-27,  but this may change depending on how long the storm lasts (it is not expected to be a long-lived event)." (April 20-21, 2018)

 

O: 22APR2018 09:21:02  19.5N  155.9W ml=3.1  ANSS   NNW of Honaunau-Napoopoo Hawai

P: 22APR2018 116142    19.9N  156.1W 3.0-4.5 AAAAA  Hawaii                     

 

O: 22APR2018 02:57:40  19.5N  156.4W ML=3.0  EMSC   HAWAII REGION, HAWAII        

P: 22APR2018 116142    19.9N  156.1W 3.0-4.5 AAAAA  Hawaii                     

 

An earthquake of M 4.0 occurred far off the Oregon coast today and may have been felt lightly in the areas of Neskowin and Nehalem, Oregon and possibly at Redding, California. This regional activation may have been promoted by an earthquake of M 6.0 south of Africa near the antipode on April 19 as noted in this summary at the time:

 

"  ... The antipode (of the Prince Edward Islands M 6.0) at 42 N 138W is off the coast of Oregon in an aseismic region, but regional seismicity off Oregon could follow." (April 20, 2018)

 

The last earthquake of M>=4.0 within about 150 km of this epicenter was an M 4.0

on March 16, 2018. A larger quake hit the area with M 5.5 on January 28, 2018. Forecast 116273 had expected today's event within about 25 km of the epicenter was likely around April 22.

 

O: 21APR2018 09:50:08  44.0N  128.6W mb=4.0  EMSC   OFF COAST OF OREGON           

P: 22APR2018 116273    44.1N  128.8W 3.0-4.6 AAAAA  Off Coast of Oregon        

 

The strongest earthquake in the U.S. or Canada today was an M 4.7 in the Unimak Island area of Alaska. It was not reported felt in this remote area. Two earthquakes in the region occurred to the east of this with M 4.5-4.6 on April 16 and 19, but the only events of larger size in the past half year were in late February, 2018 with M 4.8 and 5.1. Forecast 116305 expected today's event was likely around April 22. As the quake occurred within about 30 minutes of local solar noon, it is likely it was promoted by high tidal stresses which maximize at this hour.

 

O: 21APR2018 22:31:26  53.9N  164.0W mb=4.7  EMSC   UNIMAK ISLAND REGION, ALASKA 

P: 22APR2018 116305    54.5N  163.5W 3.5-4.9 AAAAA  Unimak Islands, Aleutians  

 

The strongest earthquake in California today was an M 3.3 in central California west of Parkfield. NEIC reported this earthquake of M 3.3 in Central California was felt with intensity II-III in the area(s) of San Ardo and King City, California.  This area often sees enhanced seismicity during and following strong geomagnetic storms. The last event of M>=3.3 within about 50 km of this epicenter occurred on August 12, 2017 (M 3.4) and prior to that an M 3.5 on April 13, 2017.  Forecast 115931 had expected an event in this ara around April 19.

 

O: 22APR2018 05:23:27  36.2N  120.8W ML=3.3  EMSC   CENTRAL CALIFORNIA           

P: 19APR2018 115931    36.1N  120.1W 2.5-5.0 BAAAA  Central California         

 

STRONG GEOMAGNETIC STORM MAY INCREASE SEISMICITY

 

EARTHQUAKE SUMMARY FOR APRIL 20, 2018

 

The geomagnetic field saw minor storm conditions today. The AP level was 47. High latitude geomagnetic field was also stormy with AP at 56. KP levels at high latitude reached 7 mid-day on April 20. It is likely this was triggered by an undetected CME from the sun. This is the most active the geomagnetic field has been since it reached AP 47 on November 8, 2017 with high latitude AP 82. This could launch a new round of increased seismicity beginning April 21 with most likely strong quakes near the geomagnetic equator and at high latitudes around April 24-27, but this may change depending on how long the storm lasts (it is not expected to be a long-lived event).

 

The earthquake of M 3.6-4.1 yesterday in Michigan occurred as this geomagnetic storm hit the earth and was probably triggered by it.

 

Several moderate earthquakes including an M 4.9 and 4.1 occurred today in Greece during a major geomagnetic storm. An M 4.7 in The region of Halkidiki and Thessalonika was felt with intensity V in Sikea and IV in Polikhronon, Kalivai Poliyirou, Ayios Paulos with lesser shaking in Kalamaria, Pilaia, Ambelokipoi, Thessalonika, Greece. This region often sees increased seismicity during geomagnetic storms. It is part of the general activation of the Anatolian Fault zone in recent weeks.

 

O: 21APR2018 01:34:41  39.9N   23.8E mb=4.1  EMSC   AEGEAN SEA                   

O: 21APR2018 00:20:03  40.0N   23.6E mb=4.9  EMSC   AEGEAN SEA                    

P: 19APR2018 116000    40.0N   23.0E 3.0-5.2 AAAAA  Romania/NW Turkey          

 

An M 2.5 quake was widely felt in the San Francisco Bay area today. NEIC reported intensity II-III for this event from Danville, Diablo, Alamo, San Ramon, Walnut Creek, Clayton, Moraga, Castro Valley, Dublin, Lafayette, Concord, Orinda, Concord, Oakland, Antioch, Martinez, Richmond, San Francisco, Livermore, Santa Clara, Manteca, Modesto, and Sacramento, California. NEIC reported an aftershock of M 2.6 in the San Francisco, California area was felt with intensity II-III in the area(s) of Danville, Lafayette and San Francisco, California.

 

O: 21APR2018 03:44:39  37.8N  122.0W MD=2.5  EMSC   SAN FRANCISCO BAY AREA, CALIF.

P: 22APR2018 116189    37.7N  121.9W 2.5-4.6 AAAAA  Central California         

 

 

The strongest earthquake in the U.S. or Canada today was an M 3.9 in Oklahoma.

NEIC reported this earthquake of M 3.9 in Kansas was felt with intensity II-III in the area(s) of Deer Creek, Oklahoma and Caldwell, Kansas. Larger earthquakes in this region often occur with strong geomagnetic storms and high tidal stresses. Earthquakes of M 5.0 and 4.5 occurred in the area on April 9 and April 7, the strongest in the past half year. Forecast 115966 had expected an event within about 50 km of the M 3.9 was likely with magnitude up to M 3.9 around April 18.

 

O: 20APR2018 19:53:33  36.9N   97.6W mb=2.7  EMSC   OKLAHOMA                     

O: 20APR2018 19:27:04  36.9N   97.6W mb=2.9  EMSC   OKLAHOMA                     

O: 20APR2018 19:28:49  36.9N   97.6W mb=3.9  EMSC   OKLAHOMA                     

O: 20APR2018 19:15:54  37.0N   97.6W mb=2.6  EMSC   OKLAHOMA                     

P: 18APR2018 115966    37.0N   97.0W 2.0-3.9 AAAAA  Southern Plains            

 

The strongest earthquake in the world today was an M 5.1 in Burma (Myanmar). NEIC reported this earthquake of M 5.1 in Myanmar was felt with intensity II-III in the area(s) of Rangoon, Myanmar.  This appears to be an aftershock of the M 6.0 that hit the same epicenter on January 11, 2018. Forecast 115876 expected this event was likely within about 50 km of this epicenter around April 20.

 

O: 20APR2018 22:29:23  18.4N   96.1E Mw=5.1  EMSC   MYANMAR                      

P: 20APR2018 115876    19.0N   96.0E 4.0-5.4 AAAAA  Andaman Islands            

 

EARTHQUAKE SHAKES MICHIGAN

 

EARTHQUAKE SUMMARY FOR APRIL 19, 2018

 

An earthquake of M 3.6-4.1 on the Michigan-Ontario border was widely felt in that area today. Earthquakes Canada reported this earthquake was felt in Windsor, Essex, Kingsville and Amherstburg, Ontario. NEIC reported intensity III-IV in Michigan through out an area about 200 km of the epicenter including at Grosselle, Rockwood, Trenton, Wyandotte, Rivervies, Southgate, Ecorse, Lincoln Park, River Rouge, Detroit, Allen Park, Flat Rock, Dearborn, Newport, Grosse Point among many other communities. NEIC reported it was felt with intensity IV in Ontario at Amherstburg, Harrow, Colchester, and lesser shaking in Tilbury, Chatham, Ridgetown, Sarnia, Paris, Brantford. It was also reported felt in Pennsylvania, Virginia, Ohio, and within about 500 km of the epicenter in Ohio at Bellville, Thompson, Chardon, Huron, Holland, Perrysburg, Woodville, Sylvania, Toledo, Oregon, Isle Saint George. When the USGS noted in a press release yesterday that an urban earthquake was likely in the near term in the U.S. Detroit, Michigan was probably not on their collective mind. The last earthquake within about 200 km of this epicenter in Michigan with M>=3.6 occurred May 2, 2015 about 200 km to the west of this epicenter with M 4.2. No earthquakes of M>=3.6 have hit this region within about 150 km in at least 25 years. Most of the regional activity occurs in Ohio which is where it had been expected at this time in the forecasts of this summary. This epicenter is located at the third node (120 degrees) from the M 7.0 in New Britain of March 29 and at the eighth node (45 degrees) from the M 8.0 in the Gulf of Alaska of January 23, 2018 and may have been promoted from these sources. Forecast 116274 had expected this activity was likely about 200 km to the east

of this epicenter around April 22.

 

 

O: 20APR2018 00:01:35  42.1N   83.1W Mw=3.6  EMSC   MICHIGAN                     

O: 20APR2018 00:01:35  42.1N   83.0W ML=4.1  NRCA  6 km ENE of Amherstburg

P: 22APR2018 116274    42.0N   80.0W 2.0-4.1 AABAA  Ohio/Lake Erie             

 

The swarm in central Nebraska also continued today with an M 3.3. NEIC reported this earthquake of M 3.3 in Nebraska was felt with intensity II-III in the area(s) of Callaway, Arnold, Merna, Stapleton, Broken Bow, Ansley, McCook, Grand Island, Omaha, Nebraska. This activity began April 9 with an M 3.3. The strongest event in the series was an M 3.7 on April 10. It is somewhat unusual for a long series to aftershocks to occur in this area and this may still be precursory to a larger event along the Pacific-North American Plate boundary to the west. Forecast 116238  expected today's aftershocks was likely around April 23.

 

O: 19APR2018 13:15:02  41.4N  100.2W mb=3.3  EMSC   NEBRASKA                      

P: 23APR2018 116238    41.0N  100.0W 2.0-4.0 BAAAA  Southern Plains            

 

The strongest earthquake of the day was an M 6.0 in the Prince Edward Islands on the South Indian Ridge south of South Africa. This is a remote oceanic area and this earthquake was not reported felt in this region. The last earthquake in the Prince Edward Islands region with M>=6 occurred on July 4, 2005 nearly 13 years ago. Other events of M>=6 in  the region occurred April 28, 1997 (M 6.6-6.8) and May 21, 1998 (M 6.3). Today's event occurred within about 30 minutes of local solar midnight and was likely promoted by high tidal stresses which maximize at this hour. This earthquake is at 101-103 degrees from the M 7.1 events in New Britain and was probably promoted from that source. Forecast 116084 had expected this event within about 200 km of the epicenter was likely around April 19.  The antipode at 42 N 138W is off the coast of Oregon in an aseismic region, but regional seismicity off Oregon could follow.

 

O: 19APR2018 21:09:17  42.8S   42.3E Mw=6.0  EMSC   PRINCE EDWARD ISLANDS REGION 

P: 19APR2018 116084    41.0S   43.0E 4.0-5.7 ABAAA  So. Indian Ocean           

 

The strongest earthquake in the U.S. or Canada today was an M 4.5 in the Unimak Island, Alaska. It was not reported felt in the region. A similar M 4.6 hit the area three days ago on April 16. The largest quake in this area in the past half year was an  M 5.1 on February 27, 2018. Forecast 116019 had expected today's activity was likely around April 21.

 

O: 19APR2018 14:37:11  53.8N  163.6W mb=4.5  EMSC   UNIMAK ISLAND REGION, ALASKA 

P: 21APR2018 116019    53.9N  165.3W 3.5-5.0 AAAAA  Fox Islands, Aleutians     

UNPRECEDENTED QUAKE HITS CENTRAL ATLANTIC

 

EARTHQUAKE SUMMARY FOR APRIL 18, 2018

 

An earthquake of M 5.5 hit the eastern Central Atlantic region today. This is  an unprecedented earthquake in this relatively non-seismic area. No earthquakes of M>=5.5 have hit this region in the past 25 years. The only event located in  the region is seismic history of the past 100 years may have been an M 6.0 about 200 km east of this on September 30, 1971. This is somewhat questionable due to the timing and stations which reported this magnitude. Today's earthquake was not alone. It followed an M 5.0 at 25 degrees to the southwest of this in the southern Mid-Atlantic Ocean 17 minutes 11 seconds earlier. The SCS phase from this earthquake, while small, was in the epicentral area of the M 5.5 when that earthquake occurred and may have helped trigger it. Seismicity at 25 West longitude in the South Sandwich Islands also continued today. A strong promoter of this activity may have been the high stresses associated with the new moon of April 16. This summary had noted in this regard:

 

 

"The new moon arrived at 01:57 UT on April 16. As with previous new and full moons this tends  to increase seismicity in longitude bands near 30W and 150E. These include the mid-Atlantic and much of the Pacific subduction zone in the east including New Guinea, the south southwest Pacific, Japan, Kamchatka and the western Aleutians. These areas could see enhanced seismicity from April 14-19 with the chance of a moderate to large quake during this period." (April 14-18, 2018)

 

These two earthquakes in the Mid-Atlantic occurred within about one hour of local solar noon and were probably promoted by high tidal stresses which maximize at this hour. Forecast 116070 had expected the southern event was likely around April 20. Forecast 115866 had expected the event off Africa to the southwest in mid-April. These events are at 144-148 degrees from the M 7.6 in PNG of February 25, a distance where seismic promotion from distant quakes is likely.

 

O: 18APR2018 13:07:19   0.4S    6.6W mb=5.5  EMSC   SOUTH ATLANTIC OCEAN         

P: 13APR2018 115866     2.0S   13.0W 4.0-5.4 BBCAA  No. of Ascension Isl       

 

O: 18APR2018 12:50:08  24.9S   13.4W mb=5.0  EMSC   SOUTHERN MID-ATLANTIC RIDGE  

P: 20APR2018 116070    20.0S   12.0W 4.0-5.6 ACAAA  So. Mid-Atlantic Ridge     

 

The strongest earthquake in the world today was an M 5.8 in Southern Iran.

NEIC reported it was felt with intensity II-III in Iran, Bahrain, Saudi Arabia, Qatar and Kuwait. No damage was immediately reported. This is the largest earthquake in Southern Iran within about 200 km of this epicenter since an M 6.4 on April 9, 2013 and prior to that an M 6.2 on May 6, 1999.  Forecast 116173 expected this event within about 50 km of this epicenter was likely around April 22. This epicenter is at the third node (120 degrees) from Bolivia and 101 degrees from New Britain (node 7), distances at which seismic promotion is likely from large quakes.

 

O: 19APR2018 06:34:46  28.4N   51.7E mb=5.8  EMSC   SOUTHERN IRAN                

P: 22APR2018 116173    28.0N   52.0E 3.5-4.9 BAAAA  So. Iran/Persian Gulf      

 

California, but especially Alaska remained at quiet seismic conditions today. An M 3.6 in the Gulf of Alaska was the strongest quake in the U.S. or Canada, the first event of M>=3 in Alaska in the past several days. The USGS admitted that no one should be surprised by a strong urban quake in California in the near term. This summary has pointed out that the next month is a period of historically increased seismicity in California. The earthquakes of M 3.8 and 4.1 in central California yesterday are a worrisome sign for a further event of moderate to large size in California in the next several weeks.

 

MODERATE QUAKE SHAKES ANTIGUA AND BARBUDA

 

EARTHQUAKE SUMMARY FOR APRIL 17, 2018

 

 

An earthquake of M 4.7 in Antigua and Barbuda today was widely felt in that region. NEIC reported it was felt with intensity V in Antigua and Barbuda at Parham, Saint Peter; IV in Freetown, Carlisle, All Saints, English Harbour, Potters Village, Swetes, Cedar Grove, Saint John's Old Road, Bolands; in Salem Montserat; New Castle, Monkey Hill, Basseterre, Mansion, Charlestown, Boyds, Saint Kitts and Nevis; in Guadeloupe at Bair-Mahault, Pointe-Noire, Point-a-Pitre, Petit-Bourg, Bouillante, and Basse-Terre. This continued an expansion of seismicity along the edges of the Atlantic Ocean which may have been promoted by the new moon tidal stresses as noted in previous summaries:

 

"The new moon arrived at 01:57 UT on April 16. As with previous new and full moons this tends  to increase seismicity in longitude bands near 30W and 150E. These include the mid-Atlantic and much of the Pacific subduction zone in the east including New Guinea, the south southwest Pacific, Japan, Kamchatka and the western Aleutians. These areas could see enhanced seismicity from April 14-19 with the chance of a moderate to large quake during this period." (April 14-17, 2018)

 

This epicenter is about 150 km north of an M 5.5 in Antigua and Barbuda of February 9 but is probably not an aftershock of it. Forecast 115888 expected this event was likely around April 12.

 

O: 17APR2018 20:26:51  17.2N   61.8W mb=4.7  EMSC   ANTIGUA AND BARBUDA REGION   

P: 12APR2018 115888    16.0N   62.0W 3.0-5.0 BBAAA  Leeward Islands            

 

The tidal stress-promoted seismicity in the Atlantic also continued today in the South Sandwich Islands with events of M 4.9 and 5.0. This continues the moderate activity in the region of the past several days. These events were not felt in the South Sandwich Islands. Forecast 116093 had expected this activity around April 17 within about 100 km of these epicenters.

 

O: 17APR2018 23:17:53  55.1S   28.5W mb=4.9  EMSC   SOUTH SANDWICH ISLANDS REGION

O: 17APR2018 23:43:06  55.2S   28.3W mb=5.0  EMSC   SOUTH SANDWICH ISLANDS REGION

P: 17APR2018 116093    56.0S   28.0W 4.0-6.0 AAAAA  So. Sandwich Islands       

 

The strongest earthquake in the U.S. or Canada today was an M 4.3 in western Montana. NEIC reported this earthquake of M 3.8-4.3 in Western Montana was felt with intensity IV in Montana at Canyon Creek, Lincoln and II-III in the area(s) of Garrison, Wolf Creek, Helena, Augusta, East Helena, Missoula, Butte, Great Falls, Hamilton and Gallatin Gateway. An aftershock of M 2.7 was felt with intensity II-III in Canyon Creek, Lincoln, Helena, Montana.  This is the strongest aftershock to date of the M 5.8 (and immediate aftershocks of M 5.4 and 5.0) which occurred on July 6, 2017. That event was one of several unlikely events in the U.S. associated with last year's solar eclipse. An M 4.2 also occurred on October 19, 2017. Forecast 115986 had expected this area would be active around April 15. These epicenters area at 104 degrees from the M 7.6 in Papua New Guinea of February 25 and were probably promoted from that source.

 

O: 17APR2018 12:36:34  46.9N  112.5W MD=2.0  EMSC   WESTERN MONTANA              

O: 17APR2018 23:03:47  46.9N  112.5W ML=2.1  EMSC   WESTERN MONTANA              

O: 17APR2018 11:41:22  46.9N  112.5W ML=2.7  EMSC   WESTERN MONTANA              

O: 17APR2018 11:11:14  46.9N  112.5W ML=4.3  EMSC   WESTERN MONTANA              

P: 15APR2018 115986    44.6N  112.0W 2.0-4.1 CAAAA  Montana/Idaho              

 

An unusually large quake in southern Quebec, Canada near Ferme-Neuve of M 3.5 also occurred today. Earthquakes Canada reported this earthquake of M 3.5 in Quebec, Canada was felt with intensity II-III in the area(s) of Ferme-Neuve, Quebec. This is the strongest earthquake within about 200 km of this epicenter since an M 3.7 on September 9, 2015. Forecast 115990 had expected this earthquake within about 50 km of this epicenter was likely around April 16.

 

O: 17APR2018 22:59:24  46.7N   75.6W ML=3.5  EMSC   SOUTHERN QUEBEC, CANADA      

O: 17APR2018 22:59:24  46.7N   75.6W ML=3.5  NRCA  12 km W   of Ferme-Neuve

P: 16APR2018 115990    47.0N   76.0W 2.0-4.1 AAAAA  New York State             

 

The strongest seismicity of the day continued in the areas of Indonesia, the Philippines and the Mariana Islands. This activity is probably being promoted after the end of the geomagnetic storm. While shocks of M 5.0 and 5.2 in the Ceram Sea of Indonesia continued, the largest event of the day was an M 5.4  South of the Mariana Islands and Guam. This event was not felt in the area.

The last earthquake within about 100 km of this epicenter south of the Mariana Islands with M>=5.4 was an M 5.6 on February 2, 2017. A series of strong quakes about 350 km to the southwest of today's epicenter hit the region on December 8, 2017. Forecast 115902 had expected this event was likely around April 12.

 

O: 18APR2018 05:32:00  11.9N  142.2E mb=5.4  EMSC   SOUTH OF MARIANA ISLANDS     

P: 12APR2018 115902    11.0N  141.0E 4.0-5.7 CAAAA  So. Marianas/Guam          

 

O: 17APR2018 06:44:01   3.6S  131.5E mb=5.0  EMSC   CERAM SEA, INDONESIA         

O: 18APR2018 07:06:55   3.7S  131.3E Mw=5.2  EMSC   CERAM SEA, INDONESIA         

P: 14APR2018 115875     6.0S  131.0E 4.0-5.4 BCAAA  West Irian, PNG             

 

CALIFORNIA GETS LUCKY

 

EARTHQUAKE SUMMARY FOR APRIL 16, 2018

 

A pair of light to moderate earthquakes were felt widely today in the area of Southern California north of Los Angeles (M 4.0) and in San Franciso (M 3.8).

The event in San Francisco occurred two minutes and 38 seconds after the M 4.0 to the south and was probably triggered by the S-wave and surface waves from that event which arrived at the San Francisco epicenter at the time that earthquake initiated. This will probably be a classic example of regional earthquake triggering by seismic waves. This can also be thought of as a strain propagating along the San Andreas Fault Zone and being relieved in the second quake in San Francisco. Motion along the fault zone did not occur except at the end points where the earthquakes occurred. This is unusual. Had the entire length between the  two epicenter had moved, California would have experienced a major earthquake - a lucky break. This does give some evidence where the weak point in Central California is – the second event - and where a strong or major quake is likely to occur next, probably with a major flare or new or full moon tidal stresses. It is also likely that this activity which occurred before noon was promoted by strong tidal stresses associated with the new moon today as  noted in the previous issue of this summary:

 

 

"Among other areas which often sees increased seismicity during new and full moon tidal stresses is the region of Central California from north of Los Angeles to San Francisco. An M 3.7 hit near Bakersfield yesterday and may indicated the area is due for some increases in seismicity following the M 5.3-5.4 south of Los Angeles in early April. There were, however, no significant events  reported in California today as the region saw very quiet conditions." (April 15-16, 2018)

 

The earthquake in San Francisco was reported by NEIC to have been felt by nearly 6000 responders with intensity II-III within about 100 km of the epicenter in the areas of Milpitas, San Jose, Mount Hamilton, Freemont, Livermore, Santa Clara, Alviso, Sunnyvale, Pleasanton, Newark and San Francisco, California among other communities. The last earthquake within about 50 km of this epicenter with M>=3.8 was an M  3.9 on December 27, 2017 and before than an M 4.1 on October 10, 2017. Forecast 115933 had expected this event within about 5 km of this epicenter was likely around April 17.

 

O: 16APR2018 16:39:26  37.4N  121.8W Mw=3.8  EMSC   SAN FRANCISCO BAY AREA, CALIF.

P: 17APR2018 115933    37.4N  121.8W 2.5-4.8 AAAAA  Central California         

 

The M 3.8-4.0 in the Bakersfield area south of San Francisco was reported by NEIC to have been felt with intensity II-III in Bakersfield, Frazier Park, Arvin, Lamont, Taft, Lebec, Bodfish, Valencia, Santa Clarita, Lancaster and Oxnard among others. The last earthquake within about 75 km of this epicenter with M>=4.1 occurred on March 12, 2016 and prior to that an M 4.2 on January 4, 2015.  Forecast 115963 had expected this event within about 10 km of the epicenter was likely around April 17.

 

O: 16APR2018 16:36:48  35.0N  119.0W ML=4.1  EMSC   CENTRAL CALIFORNIA           

P: 17APR2018 115963    34.9N  119.0W 2.5-4.6 AAAAA  So. California             

 

The strongest earthquake in the U.S. or Canada today was an M 4.6 in the Unimak Island area of Alaska. It was not reported felt in this area. The only larger events in the Unimak area in the past half year were a pair in late February on February 20 (M 4.8) and February 27 (M 5.1). Forecast 116030 had expected the Unimak area would be active in mid-April.

 

O: 16APR2018 14:51:28  53.4N  163.5W mb=4.6  EMSC   UNIMAK ISLAND REGION, ALASKA 

P: 13APR2018 116030    54.3N  162.7W 3.5-5.1 BAAAA  Unimak Islands, Aleutians  

 

The strongest seismic events of the day continued in central Indonesia in the Ceram Sea with M 5.5, 5.2 and 5.0. These follow an M 5.9-6.4 in the Molucca Sea yesterday. Today's events were not reported felt. The M 5.5 occurred near local solar noon and, like the event in Molucca yesterday were probably promoted by geomagnetic and tidal stresses which maximize at this hour. The last earthquake  in the Seram Sea of M>=5.5 was an M 6.1 on February 26, 2018, the only such event in the area in the past half year. The last event in the Seram Sea within  about 250 km of today's epicenter with M>=5.5 occurred as an  M 5.7 on March 8, 2018 and prior to that an M 5.6 on December 14, 2015. Forecasts 115612 and 115875 had expected this activity south of these epicenters in mid-April.

  

O: 16APR2018 21:15:52   3.2S  130.7E mb=4.3  EMSC   SERAM, INDONESIA             

O: 17APR2018 02:52:35   3.5S  131.3E Mw=5.5  EMSC   CERAM SEA, INDONESIA         

O: 17APR2018 06:44:06   3.5S  131.4E mb=5.0  EMSC   CERAM SEA, INDONESIA         

O: 17APR2018 04:05:10   3.6S  131.3E mb=4.4  EMSC   CERAM SEA, INDONESIA         

O: 17APR2018 04:55:57   3.6S  131.4E mb=5.2  EMSC   CERAM SEA, INDONESIA         

P: 10APR2018 115612     5.0S  131.0E 4.0-5.4 CBAAA  West Irian, PNG            

P: 14APR2018 115875     6.0S  131.0E 4.0-5.4 BCAAA  West Irian, PNG            

 

STRONG QUAKE IN MOLUCCA, INDONESIA

 

EARTHQUAKE SUMMARY FOR APRIL 15, 2018

 

The strongest earthquake of the day in the world occurred in the Molucca Sea of Indonesia with M 5.9-6.4. This was probably promoted by the end of the current geomagnetic storm as it lies about 10 degrees south of the local geomagnetic equator and had been expected in this summary as:

 

"This concludes the most active the field has been since March 25 when similar conditions existed. Other regions where seismicity can increase during geomagnetic storms include areas of high heat flow where small changes in temperature can push seismicity to a higher level. A strong earthquake could occur near the geomagnetic equator or at high latitudes around April 15-17." (April 13-15, 2018)

 

The event in the Molucca Sea was reported by NEIC to have been felt with intensity III in Manado, Sulawesi, Indonesia. BMG reported it was felt with intensity III-IV in Halmahera barat, Ternate and II-III in Bitung, Halmahera, Indonesia.  The last earthquake within about 200 km of this epicenter with M>=5.9 was an M 5.9 on November 18, 2017. The last of larger magnitude than M 6.3 occurred as an M 6.6 on December 21, 2014.  Forecast 115849 had expected this activity within about 50 km of the epicenter around April 13. This event is at 144 degrees from the M 7.6 in Honduras of January 10 and may have been promoted by concentrated seismic energy from that event.

 

O: 15APR2018 19:30:44   1.4N  126.9E Mw=5.9  EMSC   MOLUCCA SEA                  

O: 15APR2018 19:30:42  01.4N  126.8E MS=6.4  BMG  Felt with intensity III-IV

P: 13APR2018 115849     2.0N  127.0E 4.0-5.7 AAAAA  Halmahera                  

 

An M 5.2-5.4 in the northern Philippines followed the Molucca Sea quake 13 minutes later. The PcS/SCP phase from Molucca would have arrived at 15 degrees to the north in the northern Philippines at this time and may have helped trigger this Philippines event. NEIC reported this earthquake of M 5.2 in Northern Philippines was felt with intensity V in the Cagayan Valley at Turod and IV at Atulayan and II-III in the area(s) of Awallan, Casambalangan, Cagayan Valley and in Bangued, Cordillera, Philippines. PHIVOLCS reported this earthquake was felt with intensity V in Baggao, Gonzaga and Satnat Teresita, Cagayan; IV in Tuguegaro City and Enrile, Cagayan and I in Penablanca, Cagayan, Philippines. Forecast 115891 had expected this event within about 100 km was likely around April 15.

 

O: 15APR2018 19:43:56  17.9N  122.3E mb=5.2  EMSC   LUZON, PHILIPPINES           

O: 15APR2018 19:43:54  18.0N  122.3E MS=5.4  PHI  Felt with intensity V

P: 15APR2018 115891    19.0N  122.0E 3.5-5.0 ABAAA  Luzon, Philippines         

 

The region of Tonga and Fiji was also active today. The strongest regional events were M 5.2. One of these - in Tonga - occurred within 10 minutes of local solar noon, an hour when tidal stresses maximize and was probably promoted by tidal stresses associated with the new moon as previous noted in this summary:

 

 

"The new moon will arrive at 01:57 UT on April 16. As with previous new and full moons this will tend to increase seismicity in longitude bands near 30W and 150E. These include the mid-Atlantic and much of the Pacific subduction zone in the east including New Guinea, the south southwest Pacific, Japan, Kamchatka and the western Aleutians. These areas could see enhanced seismicity from April 14-19 with the chance of a moderate to large quake during this period." (April 14-15, 2018)

 

Forecasts 116059 and 116072 had expected this activity in Tonga/Fiji at this time. NEIC reported the earthquake of M 5.2 in Fiji was felt with intensity IV in the area(s) of Suva, Central Fiji.

 

O: 15APR2018 23:12:57  20.2S  177.4E mb=5.2  EMSC   SOUTH OF FIJI ISLANDS        

O: 15APR2018 12:51:23  20.5S  177.9W mb=4.4  EMSC   FIJI REGION                  

P: 17APR2018 116059    19.0S  178.0W 4.0-5.5 ABAAA  Tonga Islands              

 

O: 15APR2018 23:40:20  23.7S  175.3W mb=5.2  EMSC   TONGA REGION                 

P: 20APR2018 116072    23.0S  176.0W 4.0-5.7 BAAAA  Tonga Islands              

 

A number of other areas such as Papua New Guinea, the South Sandwich Islands, and others also saw activity today which may have tidally promoted. The earthquakes in the South Sandwich Islands of M 4.8 and 5.1 occurred near local solar midnight in an area of high tidal stress and were probably promoted by this. This is the third epicenter in the South Sandwich Islands in the past week to see moderate earthquakes. Forecast 116094 had expected this activity in mid-April.

 

O: 15APR2018 05:51:47  59.4S   25.9W mb=4.8  EMSC   SOUTH SANDWICH ISLANDS REGION

O: 16APR2018 03:30:50  59.4S   27.0W mb=5.1  EMSC   SOUTH SANDWICH ISLANDS REGION

P: 20APR2018 116094    61.0S   26.0W 4.0-5.6 BBAAA  Southern  Ocean            

 

An M 4.4 on the other end of the Atlantic today also appears to have tidally promoted as it occurred at 32 degrees West longitude. This event at the northern end of the Reykjanes ridge bucks the trend of recent event to occur at the southern end of this ridge. The last earthquake within about 200 km of this epicenter with M>=4.4 occurred on January 11, 2018 and prior to that in September 2017. Forecast 116024 expected today's event within about 50 km was likely around April 17.

 

O: 15APR2018 07:59:27  58.4N   32.0W mb=4.4  EMSC   REYKJANES RIDGE              

P: 17APR2018 116024    58.0N   32.0W 4.0-5.8 AAAAA  North Mid-Atlantic Ridge   

 

Among other areas which often sees increased seismicity during new and full moon tidal stresses is the region of Central California from north of Los Angeles to San Francisco. An M 3.7 hit near Bakersfield yesterday and may indicated the area is due for some increases in seismicity following the M 5.3-5.4 south of Los Angeles in early April. There were, however, no significant events  reported in California today as the region saw very quiet conditions.

 

MODERATELY STRONG QUAKES UNDER ATLANTIC OCEAN

 

EARTHQUAKE SUMMARY FOR APRIL 14, 2018

 

The strongest earthquakes in the world today occurred under the Atlantic Ocean at opposite ends of that body of water. The strongest of these was an M 5.4 in  the Scotia Sea north of Antarctica while a series of events of M 4.5-5.2 also occurred in the northern Atlantic near the Azores. These appear to be related to the tidal stresses with the new moon coming in a day. This summary had noted this possibility in previous issues as:

 

"The new moon will arrive at 01:57 UT on April 16. As with previous new and full moons this will tend to increase seismicity in longitude bands near 30W and 150E. These include the mid-Atlantic and much of the Pacific subduction zone in the east including New Guinea, the south southwest Pacific, Japan, Kamchatka and the western Aleutians. These areas could see enhanced seismicity from April 14-19 with the chance of a moderate to large quake during this period." (April 12-14, 2018)

 

The M 5.4 in the Scotia Sea was not felt in this remote area. It is the strongest event in the Scotia Sea region within about 250 km of this epicenter since an M 5.9 on May 6, 2017 and prior to that an M 5.5 more than 10 years ago on January 15, 2007. A major earthquake of M 7.0 hit the region on August 20, 2006 and these may be aftershocks of that event. Forecast 116094 had expected this event was likely within about 100 km of this epicenter around April 12.

 

O: 14APR2018 08:17:20  61.4S   36.8W mb=5.4  EMSC   SCOTIA SEA                   

P: 12APR2018 116094    61.0S   34.0W 4.0-5.7 AABAA  Southern  Ocean            

 

The earthquakes in the Azores, Portugal in the North Atlantic occurred at a triple point where three ocean ridges meet. Theses moderate quakes of M 4.6, 4.7, 4.8 and 5.2 were not reported felt in this region but may have been lightly felt in this remote area. An M 4.9 hit the region on March 28, 2018 but the last event of within about 300 km of these epicenters with M>=5.2 was an M 5.5 on August 30, 2107 and prior to that an M 5.3 on March 29, 2017.  Forecast 115991 had expected this activity within about 100 km of today's epicenters around April 19. This activity is at 144 degrees from the earthquakes in the South Pacific from Papua New Guinea to New Ireland and was probably promoted from that region.

 

 

O: 14APR2018 21:37:47  40.5N   29.3W mb=4.7  EMSC   AZORES ISLANDS REGION        

O: 14APR2018 17:13:39  40.5N   29.4W mb=4.6  EMSC   AZORES ISLANDS REGION        

O: 14APR2018 16:53:11  40.5N   29.6W mb=4.8  EMSC   AZORES ISLANDS REGION        

O: 14APR2018 18:34:13  40.7N   29.4W Mw=5.2  EMSC   AZORES ISLANDS REGION        

P: 19APR2018 115991    40.0N   30.0W 4.0-5.6 BAAAA  No. Mid-Atlantic Ridge     

 

The most widely felt earthquake in the U.S. or Canada today occurred near the coast of Oregon. NEIC reported this earthquake of M 3.1 off the coast of Oregon  was felt with intensity IV in Aumsville, Oregon and II-III in the area(s) of Silverton, Sublimity, Salem, Mount Angel, Scotts Mills, Salem, Turner, Molalla, Lyons, Canby, Oregon City, Newberg, Monmouth, Lake Oswego, Portland, Oregon.

This may be an aftershock of an M 4.0 that occurred near this epicenter on December 14, 2017. Forecast 115998 had expected today's activity in mid-April.

 

O: 15APR2018 03:45:41  45.0N  122.8W ML=3.1  EMSC   OREGON                       

P: 21APR2018 115998    45.3N  121.7W 2.0-3.9 CAAAA  Oregon state, U.S.         

 

NEW MOON AND UNUSUAL QUAKE IN EASTERN BRAZIL

 

EARTHQUAKE SUMMARY FOR APRIL 13, 2018

 

A highly unusual earthquake in eastern Brazil with M 3.2 was felt in the area of Santa Catarina, Brazil today. Reports on NEIC indicate intensity II-III in Sao Jose,  Florianopolis and Brusque, Santa Catarina, Brazil were associated with this minor earthquake. This may be related to the new moon which will reach maximum tidal stresses while over the central and northern Atlantic on April 16. The forecast of seismicity related to the new moon as published in the previous summary stated:

 

"The new moon will arrive at 01:57 UT on April 16. As with previous new and full moons this will tend to increase seismicity in longitude bands near 30W and 150E. These include the mid-Atlantic and much of the Pacific subduction zone in the east including New Guinea, the south southwest Pacific, Japan, Kamchatka and the western Aleutians. These areas could see enhanced seismicity from April 14-19 with the chance of a moderate to large quake during this period." (April 13, 2018)

 

One other earthquake within about 500 km of this epicenter has been recorded in the past 25 years - an M 5.2 on April 23, 2008.

 

O: 13APR2018 12:28:58  27.7S   48.8W mb=3.2  EMSC   SANTA CATARINA, BRAZIL       

 

The strongest earthquake in the world today was an M 5.4 in Hokkaido, Japan. It was followed three hours later by an M 5.0 in the Kuril Islands. This is the strongest earthquake in Hokkaido within about 250 km of this epicenter in the past half year. An earthquake of M 6.2 hit about 400 km southwest of this in Hokkaido on January 24, 2018.  Forecast 116003 had expected the Hokkaido quake was likely around April 12.

 

O: 13APR2018 18:59:55  43.3N  145.8E Mw=5.4  EMSC   HOKKAIDO, JAPAN REGION       

P: 12APR2018 116003    45.0N  146.0E 3.5-5.6 ABAAA  So. Kurils                 

P: 16APR2018 115979    42.0N  145.0E 3.5-5.8 BBAAA  Hokkaido, Japan            

 

O: 13APR2018 21:46:52  46.5N  150.9E mb=5.0  EMSC   KURIL ISLANDS                

P: 13APR2018 116005    47.0N  154.0E 3.5-5.6 AABAA  So. Kurils                 

 

There is some question about the largest quake today as GEONET gave an event north of North Island, New Zealand M up to 5.9. But most other reporters give this event M 5.0. GEONET reported this earthquake was felt with moderate intensity in the area of northern North Island,  New Zealand. 38 people reported feeling this earthquake with 28 feeling weak intensity and 10 with light intensity and none with extreme intensity in North Island, New Zealand; none felt the quake with strong to severe intensity. The last earthquake within about 150 km of today's epicenter off the east coast of North Island, New Zealand occurred on October 14, 2014 with M 6.1. A strong quake in the region occurred on April 18, 2014 with M 6.5-6.6 after a quiet period of nine years. Forecast 116078 had expected a moderate quake in this area around April 13.

 

O: 13APR2018 13:38:10  35.6S  178.5E Mw=5.0  EMSC   OFF E. COAST OF N. ISLAND, N.Z

O: 13APR2017 13:38:12  35.7S  178.6E ML=5.9  GEONET Felt with moderate intensity

P: 13APR2018 116078    37.0S  179.0E 3.5-5.1 ABAAA  E. of North Islands N.Z.   

 

The strongest earthquake in California today was an M 3.7 north of Los Angeles.

NEIC reported it was felt with intensity II-III near Caliente within about 75 km  of the epicenter. Reports of light to moderate shaking were reported at NEIC from Caliente, Bodfish, Wofford Heights, Tehachapi, Lake Isabella, Bakersfield, Weldon, Arvin, Glennville, Onyx, Frazier Park, Springville, Strathmore, California. The last earthquake in the Bakersfield area within about 50 km of this epicenter with M>=3.7 occurred nearly four years ago with an M 3.8 on June 27, 2014. That event was probably an aftershock of an M 4.2-4.3 on April 19, 2014. Forecast 115963 had expected this activity in mid-April within about 15 km of this epicenter. Today's event may have been promoted by stress redistribution following the M 5.3-5.4 in the Channel Islands, California of early April.

 

O: 13APR2018 15:24:46  35.4N  118.5W Mw=3.7  EMSC   CENTRAL CALIFORNIA           

P: 14APR2018 115963    35.7N  118.1W 2.5-4.4 AAAAA  So. California             

P: 19APR2018 115963    35.3N  118.6W 2.5-4.5 CAAAA  So. California             

 

The largest earthquake in the U.S. or Canada today was an M 4.9 in the Alaska

Peninsula where it was not reported felt. Other than an M 5.0 about 150 km northeast of this epicenter on February 23, 2018, this is the largest earthquake in the Alaska Peninsula in the past half year. Forecast 116030 had expected today's event was likely around April 17.

 

O: 14APR2018 03:29:42  54.4N  160.9W mb=4.9  EMSC   ALASKA PENINSULA             

P: 17APR2018 116030    54.7N  161.2W 3.5-5.2 BAAAA  Unimak Islands, Aleutians  

 

 

 

SOUTH SANDWICH ISLANDS REMAIN ACTIVE

 

EARTHQUAKE SUMMARY FOR APRIL 12, 2018

 

The strongest earthquake in the world today occurred as an M 5.3 in the South Sandwich Islands. It was deep and not felt in this remote area. The largest earthquake in the South Sandwich Islands in the past six months was an M 5.7 on April 9 about 100 km south of today's epicenter. Today's event appears to be a regional aftershock of that event. Forecast 116093 expected this event within about 100 km of this epicenter was likely around April 13.

 

O: 12APR2018 16:29:05  56.5S   27.4W mb=5.3  EMSC   SOUTH SANDWICH ISLANDS REGION

P: 13APR2018 116093    57.0S   26.0W 4.0-5.6 AAAAA  So. Sandwich Islands       

 

Several earthquakes of M 4.0-4.1 occurred today in the U.S. and Canada. An M 4.0  in the Southern Yukon Territory of Canada was lightly felt in that region. The only quake in the southern Yukon in the past half year with M>=4.0 was an M 4.3 about 100 km southeast of this on April 5. Forecast 116034 expected today's event within about 25 km of this epicenter around April 15.

 

O: 12APR2018 23:44:31  60.9N  138.3W ML=4.0  EMSC   SOUTHERN YUKON TERRITORY, CANA

P: 15APR2018 116034    61.0N  138.0W 3.2-5.0 BAAAA  Central Alaska             

 

The swarms in Hawaii and Yellowstone dissipated today suggesting a trigger which was short-term such as geomagnetic effects. The events of M>=2 in Yellowstone, Wyoming were no longer occurring but an M 2.2 did occur in West Yellowstone, Montana.

 

O: 12APR2018 22:50:15  44.8N  111.1W ML=2.2  EMSC   YELLOWSTONE NAT. PARK, MONTANA

P: 13APR2018 116010    44.6N  110.8W 2.0-3.9 AAAAA  Yellowstone/Wyoming        

 

An earthquake west of Yellowstone in western Montana did exceed M 3.0 today. This event is the strongest in Western Montana since an M 3.9 about 250 km north of this on January 7, 2018. Today's event is the strongest within about 200 km  of this epicenter since an M 4.0 nearly two years ago on June 14, 2016.  Forecast 115986 had expected this event was likely within about 30 km of the epicenter around April 15.  

 

O: 13APR2018 00:11:08  44.8N  112.3W ML=3.7  EMSC   WESTERN MONTANA              

P: 15APR2018 115986    44.6N  112.0W 2.0-4.1 AAAAA  Montana/Idaho              

 

The swarm in Hawaii also dissipated but a number of events in this area exceeded M 2.5 today, as they did yesterday. No event of M>3 have occurred in this swarm. Forecast 115887 had expected this activity would peak around April 17.

 

O: 12APR2018 13:50:47  19.2N  155.4W Ml=2.7  EMSC   ISLAND OF HAWAII, HAWAII     

O: 12APR2018 07:01:21  19.4N  155.3W MD=2.5  EMSC   ISLAND OF HAWAII, HAWAII     

O: 12APR2018 07:28:15  19.4N  155.3W MD=2.5  EMSC   ISLAND OF HAWAII, HAWAII     

O: 12APR2018 09:20:58  19.4N  155.3W MD=2.5  EMSC   ISLAND OF HAWAII, HAWAII     

O: 12APR2018 09:34:10  19.4N  155.3W MD=2.5  EMSC   ISLAND OF HAWAII, HAWAII     

O: 12APR2018 08:09:37  19.4N  155.3W MD=2.6  EMSC   ISLAND OF HAWAII, HAWAII     

O: 13APR2018 04:37:46  19.4N  155.3W ML=2.5  EMSC   ISLAND OF HAWAII, HAWAII     

P: 17APR2018 115887    19.3N  155.2W 3.0-4.4 BAAAA  Hawaii                     

 

The strongest earthquake in California today occurred in Southern California north of Baker and Lander, California. The last event within about 50 km of this epicenter with M>=3.2 was an M 3.7 on January 14, 2018 and prior to that an M 3.2 on June 2, 2016. Forecast 115962 expected this event was likely within about 10 km of this epicenter was likely around April 15. 

 

O: 13APR2018 02:47:50  34.9N  116.4W ML=3.2  EMSC   SOUTHERN CALIFORNIA           

P: 15APR2018 115962    34.9N  116.4W 2.5-4.9 AAAAA  So. California             

 

An earthquake of M 2.5 in Los Angeles was also widely felt.  NEIC reported this earthquake of M 2.5 in Los Angeles, California was felt with intensity IV in Carson, California and II-III in the area(s) of Gardena, Torrance, Compton, Los Angeles, Hawthorne, Lawndale, Long Beach, Huntington Beach, Ontario, Ladera Ranch, California.  Forecast 115959 had expected this event was likely in mid-April. This is the first such event in Los Angeles since the M 5.3-5.4 in the Channel Islands south of this in early April. Quakes such as this may indicate areas which were stressed by the Channel Islands quake and areas where a further moderate quake is possible and has been promoted forward in time.

 

O: 12APR2018 10:53:12  33.9N  118.3W ML=2.5  EMSC   GREATER LOS ANGELES AREA, CALI

P: 14APR2018 115959    33.8N  117.7W 2.5-4.9 AAAAA  So. California             

 

SEISMICITY UP IN YELLOWSTONE; HAWAII

 

EARTHQUAKE SUMMARY FOR APRIL 11, 2018

 

A number of areas of high heat flow showed energetic seismic activity today. In

the U.S. these included a swarm in Yellowstone of M>2 and in Hawaii at a similar magnitude level. Elsewhere the Volcano Islands of Japan were active as were volcanic areas near the equator. This activity may be related to the minor storms in  the geomagnetic field which continued today and were described in this summary in the previous issue:

 

 

"The geomagnetic field saw slightly unsettled to active conditions today.  The AP level was 18. High latitude geomagnetic field also saw minor storm conditions with AP at 34. This is the most active the field has been since March 25 when similar conditions existed. Other regions where seismicity can increase during geomagnetic storms include areas of high heat flow where small changes in temperature can push seismicity to a higher level. A strong earthquake could occur near the geomagnetic equator or at high latitudes around April 13-16." (April 10-11, 2018)

 

The activity in Yellowstone, Wyoming was low level with 8 earthquakes of M>=2 within about two hours. The largest of these was an M 2.4. It joins a series of unusual earthquakes in the central and Rocky Mountains of the U.S. over the past several days. These have included a series in central Nebraska, the largest of which was an M 3.7 and several in Oklahoma of M 4.5-5.0. The active geomagnetic conditions may be a promotional cause for these but other scenarios have been put forward in previous issues of this summary. The largest earthquake in Yellowstone in the past half year was an M 3.0 on February 25, 2018. This concluded a swarm in west Yellowstone which began February 18. Forecast 115758 had expected this swarm was likely around April 9. Yellowstone is at 106 degrees  from the M 7.6 in PNG and may have been promoted from that source. Light to  moderate quakes in the Gulf of California today occurred at a similar distance from PNG.

 

O: 11APR2018 16:42:36  44.4N  110.4W MD=2.1  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 11APR2018 16:43:46  44.4N  110.4W ML=2.0  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 11APR2018 17:41:57  44.4N  110.4W ML=2.0  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 11APR2018 17:19:19  44.4N  110.4W ML=2.1  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 11APR2018 21:13:56  44.4N  110.4W ML=2.1  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 11APR2018 16:52:15  44.4N  110.4W ML=2.2  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 11APR2018 16:50:20  44.4N  110.4W ML=2.3  EMSC   YELLOWSTONE NAT. PARK, WYOMING

O: 11APR2018 16:06:36  44.4N  110.4W ML=2.4  EMSC   YELLOWSTONE NAT. PARK, WYOMING

P:  9APR2018 115758    44.2N  110.3W 2.0-3.9 AAAAA  Yellowstone/Wyoming        

 

While there is always low level seismicity in Hawaii at Kilauea on the big island, the sudden enhancement of light earthquakes in the area suggest a resurgence of volcanism is in progress. As noted, this may be related to the ohmic heating of the magma by geomagnetic induction in the current geomagnetic storm. This series, like that in Yellowstone is likely to be short-lived if this is the case. Forecast 115623 and 115643 had expected this activity in Hawaii in early April.

 

O: 11APR2018 09:47:08  19.4N  155.3W MD=2.5  EMSC   ISLAND OF HAWAII, HAWAII

O: 12APR2018 00:30:19  19.4N  155.3W MD=2.5  EMSC   ISLAND OF HAWAII, HAWAII

O: 12APR2018 07:01:21  19.4N  155.3W MD=2.5  EMSC   ISLAND OF HAWAII, HAWAII

O: 12APR2018 07:28:15  19.4N  155.3W MD=2.5  EMSC   ISLAND OF HAWAII, HAWAII

O: 12APR2018 00:04:27  19.4N  155.3W MD=2.6  EMSC   ISLAND OF HAWAII, HAWAII

O: 12APR2018 08:09:37  19.4N  155.3W MD=2.6  EMSC   ISLAND OF HAWAII, HAWAII

O: 11APR2018 12:21:09  19.4N  155.3W MD=2.8  EMSC   ISLAND OF HAWAII, HAWAII

O: 11APR2018 10:46:08  19.4N  155.3W MD=2.9  EMSC   ISLAND OF HAWAII, HAWAII

O: 11APR2018 23:41:42  19.5N  155.4W Md=2.7  EMSC   ISLAND OF HAWAII, HAWAII     

P:  8APR2018 115623    19.9N  156.1W 3.0-4.6 BAAAA  Hawaii                     

 

O: 11APR2018 16:26:31  20.2N  155.7W ML=2.5  EMSC   HAWAII REGION, HAWAII        

P:  7APR2018 115643    20.1N  156.1W 4.0-5.6 BAAAA  Hawaii area                

 

 

The strongest earthquake in the world today occurred as an M 5.5 off the south coast of Oaxaca, Mexico. NEIC reported it was felt with intensity IV in Ixhuatan and Guichicovi, Oaxaca, Mexico. Lesser shaking may have been felt in Chiapas, Veracruz, Mexico City, Michoacan and Puebla States in Mexico. The last earthquake within about 150 km of this epicenter with M>=5.5 occurred on October 14, 2017 with M 5.5. A great quake occurred about 100 km to the east of this on September 8, 2017 (M 8.1). The largest aftershocks have reached M 5.7-5.8 and with the exception of the M 5.5 in October, 2017 all occurred within the first three weeks of the mainshock. As the largest long-term aftershock today's event takes on special significance. It suggests there is still stress in the area that could be relieved by a strong or major aftershock.  Forecast 115617 had expected this event was likely around April 9.

 

O: 11APR2018 07:30:40  15.8N   94.8W Mw=5.5  EMSC   OFFSHORE OAXACA, MEXICO

O: 11APR2018 07:30:42  15.8N   94.8W mw=5.5  ANSS   Francisco del Mar Mexico

O: 11APR2018 07:30:38  15.5N   95.0W ML=5.5  UNAM  l SUR de SALINA CRUZ, OAX *: 15

P:  9APR2018 115617    16.0N   94.0W 3.5-5.1 AAAAA  Chiapas, Mexico            

 

The strongest earthquake in the U.S. or Canada today occurred in southern Alaska near Valdez with M 4.1.  NEIC reported this earthquake of M 4.1 in Southern Alaska was felt with intensity II-III in the area(s) of Valdez, Seward, Anchorage, Girdwood, Eagle River, Elmendord AFB, Wasilla, Soldotna, and Cordova, Alaska.  This is the first event of M>=4.1 within about 100 km of this epicenter since an M 5.3 on November 27, 2017 and prior to that an M 4.4 on July 11, 2017, the only such regional events in the past year. This epicenter is at 105 degrees from the M 6.8 in Bolivia of April 2, 2018 and may have been promoted from this source. Forecast 115781 had expected today's event in early April.

 

O: 11APR2018 16:44:11  60.6N  147.6W ML=4.1  EMSC   SOUTHERN ALASKA              

P:  2APR2018 115781    60.1N  148.4W 3.2-5.1 CAAAA  Central Alaska             

 

STRONG CHILE QUAKE RELATED TO GEOMAGNETIC STORM

 

EARTHQUAKE SUMMARY FOR APRIL 10, 2018

 

A strong earthquake of M 6.2 in Central Chile in Coquimbo today was widely felt. NEIC reported intensity VII in Coquimbo at Salamanca; VI in Illapel; V in Ovalle, Coquimbo, Vicuna, Coquimbo and in Limache, Valparaiso. Intensity IV was felt as far as 250 km in Valparaiso at Vina del Mar, La Serena, Quilpue, Vallenar, and in San Rafael, Mendoza, Argentina.  CSN reported this earthquake was felt with intensity VI in  Zapallar, Punitaqui, La Serena, Andacollo; V Alto del Carmen, Huasco, Vallenar, Coquimbo, La Higuera, Los Vilos, Ovalle, Algarrobo, Cartagena, El Quisco, El Tabo, La Ligua, Llaillay, Los Andes, Nogales, Quillota, Rinconada, San Antonio, San Felipe, Santo Domingo, Valparais, Villa Alemana, Vina del Mar, IV Mostazal, Tiltil, Talaganet, Santiago, Puente Alto, Penaflor, Padre Hurtado, Lampa, Isla de Maipo, El Monte, Colina, Quilpue, Olmue, Limache, Tierra Amarilla, Copiapo and II-III in Melipilla, Paredones, Rancagua, San Fernando, Curico, Molina, Pencahue, Rio Claro, Talca, Concepcion, Felt in Atacama, Coquimbo, Valparaiso, Metropolitana, O'Higgins, Maule and Biobio, Chile. This is the strongest earthquake within about 250 km of this epicenter since an M 6.9 on April 24, 2017, a year ago, and prior to that an M 6.3 within about 100 km of today's epicenter on February 10, 2016. A great earthquake occurred about 50 km south of this on September 16, 2015 with M 8.3. Today's event is probably a long-term aftershock of that event. Forecast 115828 expected this event within this region was likely around April 7 to the north of this epicenter. It was located about 15 degrees south of the geomagnetic equator and may have been promoted by the minor geomagnetic storm which  coincided with the quake.

 

O: 10APR2018 10:19:34  31.0S   71.4W Mw=6.2  EMSC   COQUIMBO, CHILE              

O: 10APR2018 10:19     31.0S   71.6W mb=6.2  GUC    Zapallar, Punitaqui, La Serena

P:  7APR2018 115828    30.0S   72.0W 4.0-5.5 BAAAA  Coast Central Chile        

 

A moderate earthquake of M 4.6 occurred in northern India today. ASC reported

it was felt in parts of Singrauli District near Rihand reservoir in eastern Madhya Pradesh. It was felt with intensity IV in Bargawan, Jayant, Morwa, Singrauli, Vidhyanagar and Waidhan. People fled outside in Ampara and Bijipur and cracks developed in building walls in Anpara. Some power outages were reported. The event was also reported felt with lighter intensity II-III in Bagni, Bina, Ghorawal, Arma, Khaliari, Myorpur, Ramgarh, Renukoot, Robersganj, Shaktinagar, Sukrit and Waini and in Gurmura, Hkariya and Obra with lesser intensity. One person fainted in Gainiari-Baliari and was hospitalized due to the quake. This event occurred about 15 degrees north of the geomagnetic equator and may have been promoted by the current geomagnetic storm. If it is reservoir-related seismicity, this too can be promoted by  geomagnetic effects. The last earthquake of M>=4.6 within about 200 km of this epicenter in India was an M 5.0 on October 18, 2012 and prior to that an M 4.8 on June 12, 2001. The strongest event in the area in the past 25 years was an M 5.8 southwest of this on May 21, 1997. Regional activity had been expected for the period around April 11.

 

NEIC reported this earthquake of M 4.6 in northern India was felt with intensity V in Pipri, Uttar Pradesh,  IV in Tribuvannagar, Dang Deokhuri, Nepal and II-III in the area(s) of Renukut, Uttar Pradesh and Sidhi, Madhya Pradesh, India.

 

 

O: 10APR2018 14:14:19  24.1N   82.6E mb=4.6  EMSC   MADHYA PRADESH REGION, INDIA 

P: 11APR2018 115649    27.0N   88.0E 3.5-5.5 ACCAA  Nepal                      

 

Two moderate earthquakes of M 4.3 and 4.5 were lightly felt in the Virgin Islands today. They were reported felt in Puerto Rico. These may also have been promoted by the geomagnetic storm today as they occur in a region of high heat flow and volcanism. The area of the Virgin Islands has been active in recent week including an M 4.7 on April 6, an M 4.5 on March 15 and an M 4.9 on February 9, 2018. Forecast 115624 had expected this event within about 50 km was likely around April 8. This activity is located at the fifth node (72 degrees) from the  great M 8.0 in the Gulf of Alaska of January 23, 2018.

 

O: 11APR2018 01:03:50  19.1N   64.5W mb=4.3  EMSC   VIRGIN ISLANDS REGION        

O: 10APR2018 13:08:11  19.2N   64.2W ML=3.0  EMSC   VIRGIN ISLANDS REGION        

O: 11APR2018 00:48:14  19.2N   64.4W ML=3.2  EMSC   VIRGIN ISLANDS REGION        

O: 11APR2018 01:00:24  19.3N   64.7W mb=4.5  EMSC   VIRGIN ISLANDS REGION        

P:  8APR2018 115624    19.0N   64.0W 3.0-5.0 BAAAA  Leeward Islands            

 

 

Some of this activity was probably promoted by minor storm conditions in the geomagnetic field. The quakes in Chile and in India lie at about 15 degrees south and north of the geomagnetic equator. These are most likely to affect areas where water or lava is a prime agent in modulating regional seismicity and near the geomagnetic equator and high latitudes. Such regions include Taupo, New Zealand, Volcanic regions and Yellowstone National Park, U.S. among others. This summary stated in this regard:

 

"The geomagnetic field saw slightly unsettled to active conditions today.  The AP level was 18. High latitude geomagnetic field also saw minor storm conditions with AP at 34. This is the most active the field has been since March 25 when similar conditions existed. Other regions where seismicity can increase during geomagnetic storms include areas of high heat flow where small changes in temperature can push seismicity to a higher level. A strong earthquake could occur near the geomagnetic equator or at high latitudes around April 13-16." (April 10-11, 2018)

 

The largest earthquake in the U.S. or Canada today was an M 3.7 in Central Nebraska. The earthquake of M 3.3 in central Nebraska yesterday was followed by a series including an M 3.7 today. This is unusual and may further point to a strong western U.S. quake in the next week. Seismicity often peaks in the western U.S. in late March through mid-April. This has included notable earthquakes in Alaska in March, 1964 and in San Francisco in April, 1906 among many others. In the case of California this has been related to weather patterns and this is likely the case in Alaska as well. This, along with moderate seismicity in Oklahoma may also be promoted by the geomagnetic storm today. The mainshock of M 3.7 was reported with intensity IV in Nebraska at Callaway and II-III in Arnold, Merna, Stapleton, Brady and Ogallala, Nebraska. Aftershocks in Nebraska were felt in Stapleton, Arnold and Broken Bow, Nebraska with intensity II-III. In the previous issue this summary addressed this unusual sequence as:

 

 

"The most unusual earthquake in the U.S. today was an M 3.3 in Central Nebraska. NEIC reported it was felt with intensity IV in Arnold, Nebraska and II-III in Callaway, Merna, Stapleton, Broken Bow, Brady, North Platte, Minden, McCook, Saint Paul, Lincoln, Raymond and Clearwater, Nebraska. It was also reported from Plankinton, South Dakota. Light earthquakes in this area, prior to the activation of the central U.S. Plain States in 2011, were considered in this summary to be mine canaries, often followed within hours or days by strong quakes along the western U.S. plate transitions in Alaska, Washington or California. This relation is no longer as clear-cut but may still show a relation of unusual quakes in those regions. In the current case the M 5.0 and 4.5 in Oklahoma and the M 5.3-5.4 in the Channel Islands south of Los Angeles, California may have promoted this event in Nebraska, but a major earthquake is still possible in the activation of western U.S. in the next several days. The last event within about 100 km of this epicenter in Nebraska was an M 3.5 on January 4, 2014 and prior to that an M 3.6 on August 19, 2015. These are the only such earthquakes in this area in the past 15 years - since an

M 4.2 on November 3, 2002." (April 10, 2018)

 

Note that the M 3.7 in Nebraska is the strongest since the M 4.2 in that region

of November 3, 2002.

 

O: 10APR2018 11:41:06  41.4N  100.1W mb=3.7  EMSC   NEBRASKA                     

O: 10APR2018 11:55:02  41.4N  100.2W mb=2.5  EMSC   NEBRASKA                     

O: 10APR2018 15:49:10  41.4N  100.2W mb=3.1  EMSC   NEBRASKA                     

 

MODERATE QUAKES IN OKLAHOMA AND NEBRASKA AND SEISMIC POTENTIAL IN WESTERN U.S.

 

EARTHQUAKE SUMMARY FOR APRIL 9, 2018

 

The strongest earthquake in the U.S. or Canada today, like yesterday, occurred in the region of Oklahoma. Today's event of M 4.5, while smaller than the M 5.0 of April 7, and is the second strongest in the region in the past half year. It was felt in much the same area as the M 5.0 which was described in this report as:

 

"One of the strongest earthquakes in Oklahoma in the current series occurred today with M 4.6 (ANSS) to M 5.0 (EMSC). NEIC reported it was felt throughout much of Oklahoma and Kansas and as far as Missouri, Arkansas, Texas, Tennessee, Kentucky and possibly Wisconsin. Maximum shaking was V reported at Billings, Oklahoma and IV in Perry, Mulhall, Enid, Crescent, Hennessey and in general within about 50 km of this epicenter. Several M 3.0 foreshocks preceded the mainshock. The last earthquake in Oklahoma within about 200 km of today's epicenter with M>=5 was an M 5.0 on November 7, 2016. Since the region became active in 2011 six earthquakes of M>=5 have occurred in or near Oklahoma - in November, 2011 and in 2016 on February 13, September 3 and November 7. Of these two were of M 5.6-5.8. Forecast 115707 had expected today's event was likely around April 6." (April 8, 2018)

 

Like the last event of M>=5, the last of M 4.5-4.9 in Oklahoma occurred in November, 2016 as an M 4.5 on November 2, 2016 and prior to that on January 7, 2-16 with M 4.8.

 

The most unusual earthquake in the U.S. today was an M 3.3 in Central Nebraska. NEIC reported it was felt with intensity IV in Arnold, Nebraska and II-III in Callaway, Merna, Stapleton, Broken Bow, Brady, North Platte, Minden, McCook, Saint Paul, Lincoln, Raymond and Clearwater, Nebraska. It was also reported from Plankinton, South Dakota. Light earthquakes in this area, prior to the activation of the central U.S. Plain States in 2011, were considered in this summary to be mine canaries, often followed within hours or days by strong quakes along the western U.S. plate transitions in Alaska, Washington or California. This relation is no longer as clear-cut but may still show a relation of unusual quakes in those regions. In the current case the M 5.0 and 4.5 in Oklahoma and the M 5.3-5.4 in the Channel Islands south of Los Angeles, California may have promoted this event in Nebraska, but a major earthquake is still possible in the activation of western U.S. in the next several days. The last event within about 100 km of this epicenter in Nebraska was an M 3.5 on January 4, 2014 and prior to that an M 3.6 on August 19, 2015. These are the only such earthquakes in this area in the past 15 years - since an M 4.2 on November 3, 2002. The relation between larger quakes in Alaska and those in Nebraska was noted in this summary at the time:

 

"The major news in the U.S. and Canada today was the Mw 7.9 in Central and southern Alaska. This is probably the strongest earthquake in this region and in the U.S. and Canada continental area since the great Good Friday earthquake of March 28, 1964.

 

The largest earthquake in the lower 48 states occurred about an hour and a half before the Alaska earthquake with Ml 4.3 in eastern Nebraska." (November 4, 2002)

 

 3 28 10  8 43 1964  43.000 -101.600  16 5.0   Wyoming/Dakotas

 

This repeated a pattern from the great earthquake of March 28, 1964 of M>9 in the area of southern Alaska - the largest quake recorded in recent history in North America. On March 28, 2018, this summary reminded  readers in the history section of the relation between this event in Nebraska and the subsequent quake in Alaska as:

 

"A foreshock occurred on March 27. Furniture vibrated and moved at Van Tassell. Also felt in Nebraska and South Dakota.

 

This event was felt over a large area of Nebraska, South Dakota, and border areas of Montana and Wyoming. It was the most widely felt shock since that of November 15, 1877 and was the first to center in Nebraska since March 1, 1935. At Alliance, part of a  Chimney cap fell on one residence. A highway about 10 miles south of Merriam sustained about 75 cracks and steep banks reportedly fell into the Niobrara River. Plaster fell, walls cracked and several dishes broke. Slight damage was also obtained in Martin and Deadwood, So. Dakota. The logical conclusion is that this event and the others in the western U.S. on this and the previous date were in some way related to the great Alaska  earthquake." (March 28, 2018)

 

 

O:  9APR2018 09:33:46  41.4N  100.1W mb=3.3  EMSC   NEBRASKA                     

 

It is of some interest that five days ago on April 4, an M 5.0 earthquake in the Mid-Indian Ridge occurred. This epicenter is within 25 km of the exact antipode of the Nebraska quake today. This event was the strongest earthquake within about 200 km of this unusual epicenter since an M 5.5 on June 24, 2017 and prior to that an M 5.5 on May 18, 2015.  

 

O:  4APR2018 13:11:42  41.6S   80.1E mb=5.0  EMSC   MID-INDIAN RIDGE             

P:  4APR2018 115831    37.0S   79.0E 4.0-5.5 ACAAA  So. Indian Ocean           

 

An M 4.7 earthquake was widely felt in Central Italy today continuing the re-activation of this region in the past week. Today's event was reported by NEIC to have been felt with intensity IV in Amondola, Marken, Italy and in Foligno, Umbria. Intensity II-III was reported from Marken at Camerino, Apiro, Macerata, Serra San Quirico, Ascoli Piceno, Numana, and Pesaro and in Rome Italy and in Umbria at Perugia, Todi, and Assisi, Italy.

 

"One of the areas of western Europe which has been active since the full moon is central Italy. This became active with the full moon on March 31 with an M 3.9 and has continued to produce light to moderate quakes since that time. The

 largest today was an M 4.3, the strongest in the area since an M 4.6 on December 3, 2017. This activity is likely to continue for several more days." (April 4, 2018)

 

Today's event of M 4.7 was followed by a strong aftershock sequence including an  M 3.5. Many of these were felt with light intensity in central Italy. The last earthquake in central Italy of M>=4.7 occurred with the mainshock of January 18, 2017 of M 5.7 with aftershocks of M 4.7, 5.6 and 5.2. Forecast 115727 had expected this activity was likely around April 10 in Italy.

 

O: 10APR2018 03:11:31  43.1N   13.0E mb=4.7  EMSC   CENTRAL ITALY                

P: 10APR2018 115727    43.0N   14.0E 3.0-5.6 AAAAA  Italy                      

 

A moderately strong earthquake of M 5.1-5.5 also occurred north of North Island, New Zealand today. This was the largest earthquake of the day.  GEONET reported this quake was felt with moderate intensity in the area of northern North Island,  New Zealand. 18 people reported feeling this earthquake with 12 of weak intensity and 4 with light intensity in North Island, New Zealand; one felt the quake with moderate and one with strong to severe intensity. The quake occurred within about 30 minutes of local solar midnight and was probably promoted by tidal stresses which maximize at this hour. The tidal quake forecast for the full moon had emphasized the region of New Zealand and western Europe (Italy) as:

 

" ... As with the past two full moons this will affect most strongly seismicity in the Atlantic Ocean and western Europe in the west near 10W and in the east near 170E in the region from Fiji and Vanuatu south to New Zealand ... " (April 1-4, 2018)

 

The last earthquake in New Zealand within about 200 km of this epicenter off North Island with M>=5.5 occurred October 8, 2016 with M 5.5. A major quake of M 7.1 hit the region on September 1, 2016.  Forecast 115830 had expected this event was likely in early April. Many areas with horizontal motion caused by seismic events such as in southern California, and the Anatolian Fault in Turkey and Greece have been active in the past several days and this pattern is likely to continue as in this event in New Zealand.

 

O: 09APR2018 12:14:23  37.1S  178.9E ML=5.5  GEONET Felt with moderate intensity

O:  9APR2018 12:14:25  37.3S  179.0E mb=5.1  EMSC   OFF E. COAST OF N. ISLAND, N.Z

P:  6APR2018 115830    38.0S  177.0E 3.0-4.5 BABAA  North Island, N.Z.         

 

The strongest aftershock of the M 5.3-5.4 quake in the Channel Islands south of Los Angeles, California of April 5, 2018 occurred today with M 2.7. Today's event was reported felt with intensity II in San Dimas, California. Forecast 115699 had expected this event within about 5 km of this epicenter around April 11.

 

O: 10APR2018 07:04:12  33.8N  119.7W ML=2.7  EMSC   CHANNEL ISLANDS REG., CALIFORN

P: 11APR2018 115699    33.8N  119.7W 2.5-4.7 AAAAA  So. California              

 

 

MODERATELY STRONG QUAKE SHAKES WESTERN HONSHU, JAPAN

 

EARTHQUAKE SUMMARY FOR APRIL 8, 2018

 

A moderately strong earthquake of M 5.6-5.7 was widely felt in western Honshu, Japan today. NEIC gave maximum intensity VI in Izumo, Shimane with V in Hikawa and IV in Matsue, Shimane. It was also felt with intensity IV-V in Tottori, Hiroshima, Yamaguchi, Okayama, and II-III in Tottori, Ehime, Kagawa, Kochi, Fukuoka, Hyogo, Oita, Fukuoka, Osaka, Kyoto, Shiga and Kanagawa and in general within about 300 km from the epicenter. NEIC reported aftershocks of M 4.7 each in Western Honshu, Japan were felt with intensity II-III in the area(s) of Izumo, Shimane, Hiroshima and Okayama, Japan. About 1000 homes lost water and/or power and some roads cracked. At least one person was injured in the quake which was followed by three moderate aftershocks of M 4.5-4.7. The last earthquake within about 200 km of this epicenter was an M 6.2 on October 21, 2016 and prior to that an M 6.3 i Kyushu on March 13, 2015 and a similar M 6.3 on June 11, 2006.  Forecasts 115678 and 115426 had expected the area to be active in late March or early April.

 

O:  8APR2018 17:10:57  35.0N  132.6E mb=4.7  EMSC   WESTERN HONSHU, JAPAN        

O:  8APR2018 16:43:54  35.1N  132.5E mb=4.4  EMSC   WESTERN HONSHU, JAPAN        

O:  8APR2018 16:56:46  35.1N  132.6E mb=4.7  EMSC   WESTERN HONSHU, JAPAN        

O:  8APR2018 16:32:31  35.1N  132.6E mb=5.7  EMSC   WESTERN HONSHU, JAPAN        

O: 08APR2018 16:32:31  35.3N  132.5E mw=5.6  ANSS   NNE of Oda Japan

O:  8APR2018 20:05:44  35.2N  132.6E mb=4.4  EMSC   WESTERN HONSHU, JAPAN        

P: 10APR2018 115678    32.0N  132.0E 3.5-4.9 ACAAA  Kyushu, Japan area         

P: 30MAR2018 115426    34.0N  132.0E 3.5-4.9 CBAAA  Kyushu, Japan area         

 

An M 5.7 also occurred in the South Sandwich Islands at an intermediate depth today. Most quakes in this area are not felt and this event was not reported felt in this epicentral region either. The last earthquake in the South Sandwich Islands with M>=5.7 occurred on September 4, 2017 with M 6.0 and prior to that on May 30, 2017 (M 5.7). Forecast 115840 had expected today's event within about 100 km of this epicenter was likely around April 4.

 

O:  9APR2018 00:20:54  57.7S   27.8W Mw=5.7  EMSC   SOUTH SANDWICH ISLANDS REGION

P:  4APR2018 115840    57.0S   27.0W 4.0-5.9 BAAAA  So. Sandwich Islands       

 

An earthquake of M 3.4 in eastern Los Angeles today occurred near local solar midnight and may have been promoted by tidal stresses. NEIC reported this earthquake was felt with intensity IV in Crestline and Riverside, California and II-III within about 50 km of the epicenter. Communities closest to the epicenter which reported intensity II-III included Lytle Cree, Mt Baldy, Rialto, Fontana, Rancho Cucamonga, Hesperia, Rialto, Wrightwood, San Bernardino, Bloomington, Upland and Ontario, California. The last earthquake of M>=3.4 within about 50 km of this epicenter was an M 3.4 on July 16, 2017 and prior to that an M 3.5 on March 18, 2017. The last earthquake in the region of M>4 was an M 4.4 on December 30, 2015 to the east of today's epicenter. Forecast 115698 had expected this event within about 25 km was likely around April 8. This is the first event in Los Angeles of M>3 since the M 5.4 quake south of Los Angeles of April 5. Two light aftershocks of M 2.0-2.5 also hit the region of islands south of Los Angeles, the first significant aftershocks in the region. Some areas are likely to be promoted by stress migration from the M 5.4 mainshock, the strongest in the region in more than 24 years, since the Northridge quake and aftershocks of 1994. It is often helpful to note the epicenters of these regional aftershocks to see where stress is most likely to generate moderate quakes in the near term. The M 6.1 Borrego Springs earthquake celebrates its 50th anniversary today having occurred on April 9, 1968. This is an area where a repeat is likely in the not distant future. 

 

O:  9APR2018 07:31:59  34.3N  117.5W ML=3.4  EMSC   SOUTHERN CALIFORNIA          

P:  8APR2018 115698    34.2N  117.8W 2.5-5.0 AAAAA  So. California             

 

NEIC reported the aftershock of M 2.5 in the Santa Cruz Islands, California was felt with intensity II-III in the area(s) of Oxnard, Ojai, Los Angeles, Ontario and Victorville, California.

 

O:  8APR2018 11:22:53  33.9N  119.7W ML=2.5  EMSC   CHANNEL ISLANDS REG., CALIFORN

O:  8APR2018 17:32:00  34.0N  119.3W ML=2.0  EMSC   CHANNEL ISLANDS REG., CALIFORN

P:  4APR2018 115700    34.7N  119.0W 2.5-4.8 AAAAA  So. California             

P: 11APR2018 115699    33.8N  119.7W 2.5-4.7 AAAAA  So. California             

 

 

 

 

MODERATE QUAKE SHAKES OKLAHOMA AND KANSAS

 

EARTHQUAKE SUMMARY FOR APRIL 7, 2018

 

One of the strongest earthquakes in Oklahoma in the current series occurred today with M 4.6 (ANSS) to M 5.0 (EMSC). NEIC reported it was felt throughout much of Oklahoma and Kansas and as far as Missouri, Arkansas, Texas, Tennessee, Kentucky and possibly Wisconsin. Maximum shaking was V reported at Billings, Oklahoma and IV in Perry, Mulhall, Enid, Crescent, Hennessey and in general within about 50 km of this epicenter. Several M 3.0 foreshocks preceded the mainshock. The last earthquake in Oklahoma within about 200 km of today's epicenter with M>=5 was an M 5.0 on November 7, 2016. Since the region became active in 2011 six earthquakes of M>=5 have occurred in or near Oklahoma - in November, 2011 and in 2016 on February 13, September 3 and November 7. Of these two were of M 5.6-5.8. Forecast 115707 had expected today's event was likely around April 6.

 

O: 07APR2018 16:21:22  35.7N   97.4W mb=3.1  EMSC   OKLAHOMA CITY AREA, OKLAHOMA

O: 07APR2018 10:13:42  36.2N   97.6W mb=2.5  EMSC   OKLAHOMA

O: 07APR2018 11:00:03  36.2N   97.6W mb=2.5  EMSC   OKLAHOMA

O: 07APR2018 09:48:03  36.2N   97.6W mb=3.0  EMSC   OKLAHOMA

O: 08APR2018 03:32:24  36.3N   97.5W mb=2.4  EMSC   OKLAHOMA

O: 07APR2018 19:37:56  36.3N   97.5W mb=2.5  EMSC   OKLAHOMA

O:  7APR2018 12:16:02  36.3N   97.5W mb=5.0  EMSC   OKLAHOMA                     

P:  6APR2018 115707    36.0N   97.0W 2.0-3.9 AAAAA  Southern Plains            

 

A moderate earthquake of M 5.2-5.3 shook regions of Guatemala today. NEIC reported it was felt with intensity II-III in the areas of Escuintla, Quezaltenango, Sacatepequez, Guatemala City, Guatemala and outside Guatemala in Tapachula, Chiapas, Mexico and La Libertad, El Salvador.  The only earthquake in Guatemala to exceed M 5.2 in the past half year was an M 5.4 on December 29, 2017. Forecast 115621 had expected today's earthquake was likely around April 5.

 

O:  8APR2018 05:08:26  13.9N   91.4W Mw=5.2  EMSC   OFFSHORE GUATEMALA           

O:  8APR2018 05:34:29  13.9N   91.7W mb=4.4  EMSC   OFFSHORE GUATEMALA           

O:  7APR2018 08:06:29  14.3N   91.3W mb=4.1  EMSC   GUATEMALA                    

P:  5APR2018 115621    14.0N   92.0W 3.5-5.3 AAAAA  Guatemala                  

 

In addition to the event in Guatemala, a pair of events of M 4.6 and 4.7 occurred today in the Galapagos Islands at 91 West longitude. These too appear to have been promoted by tidal stresses aas they occurred within about an hour of local solar midnight and noon. An M 5.0 on the northern Mid-Atlantic Ridge may have been promoted by similar stresses.

 

O:  8APR2018 04:55:19   1.2N   90.8W mb=4.6  EMSC   GALAPAGOS ISLANDS REGION     

O:  7APR2018 19:33:13   1.4N   90.9W mb=4.7  EMSC   GALAPAGOS ISLANDS REGION     

P:  5APR2018 115583     2.0N   91.0W 3.5-5.1 AAAAA  Galapagos Islands          

 

O:  8APR2018 01:12:09  18.5N   47.6W mb=5.0  EMSC   NORTHERN MID-ATLANTIC RIDGE  

P:  8APR2018 115629    15.0N   45.0W 4.0-5.5 ACBAA  Mid-Atlantic Ridge         

 

A moderate earthquake also shook regions of western Turkey today in the region of Bolu, east of Istanbul on the Anatolian Fault zone. NEIC reported it was felt in Turkey in the areas of Bolu (intensity IV) and II-III in Duzce, Ankara, Golcuk, Kocaeli, and Istanbul. If this represents a new activation of the Anatolian Fault, a moderately large to large quake near Istanbul could occur in the near term. Horizontal ground motions such as in east Africa, Southern California and New Zealand tend to encourage similar motion such as on the Anatolian Fault in Turkey and Greece. The last earthquake within about 200 km of today's epicenter occurred as an M 5.3 on October 15, 2016 and prior to that an M 5.0 on November 24, 2013.   Forecast 115741 had expected this event within about 50 km of the epicenter was likely around April 9. This event occurred within about 30 minutes of local solar midnight and was probably promoted by tidal stresses which maximize at this hour.

 

O:  7APR2018 21:16:31  40.9N   31.7E ML=4.8  EMSC   WESTERN TURKEY               

P:  9APR2018 115741    41.0N   31.0E 3.5-5.0 AAAAA  No. Turkey/Black Sea       

 

An unusually large earthquake of M 3.4 occurred in southern Idaho today.  NEIC reported this earthquake of M 3.4 in Southern Idaho was felt with intensity II-III in the area(s) of Soda Springs, Montpelier and Preston, Idaho. This is part of the series which began on September 2, 2017 with an M 5.3  and has included aftershocks of M 4.3 and 4.1 on January 26, 2018 and October 11, 2017 (M 4.1).

Forecast 115758 had expected this activity to continue with another light quake in early April. Today's Idaho event was preceded by an M 2.7 in Colorado about 21 minutes earlier. Both occurred within about 10 minutes of local solar midnight and were probably promoted by tidal stresses which maximize at this hour. Forecast 115674 had expected the event in Colorado in early April.

 

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

 

O:  7APR2018 07:22:58  42.6N  111.4W ML=3.4  EMSC   SOUTHERN IDAHO               

P:  1APR2018 115758    43.2N  111.0W 2.0-3.9 CAAAA  Yellowstone/Wyoming        

 

O:  7APR2018 07:01:52  39.8N  107.4W ML=2.7  EMSC   COLORADO                     

P:  3APR2018 115674    39.2N  108.4W 2.0-4.0 BAAAA  Colorado area              

 

 

PAPUA NEW GUINEA CONTINUES TO SHAKE

 

EARTHQUAKE SUMMARY FOR APRIL 6, 2018

 

The strongest seismicity in the world today occurred in the region of Papua New Guinea. An M 6.3 hit the aftershock area of the February 25, 2018 (M 7.6) event and an M 5.5 hit northwest of this along the northern coast of New Guinea earlier in the day. These areas lie at 101-103 degrees from the M 5.4 south of Los Angeles, California which occurred on April 5 and may have been promoted from that source among others. This summary had expected this in previous issues as:

 

"... A further triggered moderate quake in the area is still considered a possibility in the next week. In addition to being 101-102 degrees from PNG today's event is also at 106 degrees from the M 6.1 in Mindanao yesterday and may have been promoted from both those areas. Further activity in PNG and to the west of the February event will probably tend to bring more seismicity to Los Angeles especially if it occurs with moderate to large magnitude and seismic ping-pong begins between these two areas in the next several days before stress hardening occurs." (April 6, 2018)

 

The strongest earthquake of the day - the M 6.3 aftershock in New Guinea may have been promoted by an M 5.4 in New Ireland which occurred minutes earlier about 10 degrees to the east of the PNG epicenter. NEIC reported the PNG quake was felt with intensity IV in PNG at Porgera, Enga, Kiunga, Fly River and

II-III in Laiagam, Enga; Mount Hagen, Western Highlands; Aitape, East Sepik; Goroka Eastern Highlands. This is the strongest aftershock in this region of the M 7.6 of February 25, 2018 since an M 6.7 on March 6, 2018, a month ago. Prior to that besides the mainshock of February 25 the last quake of M>=6.3 within about 200 km of this epicenter occurred on March 3, 2000 with M 6.6. Forecast 115603 had expected today's aftershock was likely around April 4-5. It is located at 143 degrees from the M 6.8 in Bolivia of April 2, a distance at which triggering is likely due to concentration of energy at the surface. Other quakes in Indonesia occurred at this distance from Bolivia today in northern PNG and in the Sumba region (M 5.0). 

 

O:  7APR2018 05:48:42   5.9S  142.6E Mw=6.3  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

P:  4APR2018 115603     6.0S  143.0E 4.0-5.5 BAAAA  Papua New Guinea           

P:  5APR2018 115603     5.0S  144.0E 4.0-5.4 AABAA  Papua New Guinea           

 

O:  7APR2018 05:15:21   5.5S  152.0E mb=5.4  EMSC   NEW BRITAIN REGION, P.N.G.   

P:  2APR2018 115596     5.0S  152.0E 4.0-5.6 BAAAA  New Britain                

 

The M 5.5 in northern PNG was located near the epicenter of the M 8.0 of January 10, 1971 which may have helped promote the M 6.7 in the San Fernando Valley of Los Angeles a month later on February 9, 1971. Today's event could encourage further seismicity in the region of Los Angeles, California.  BMG reported today's earthquake in Northern PNG was felt with intensity III in Sarmi, Papua New Guinea, Indonesia. The last earthquake of M>=5.5 within about 200 km of today's epicenter occurred on September 24, 2016 with M 5.6. An M 7.0 occurred about 250 km east of this on July 17, 1998. Forecast 115611 had expected today's event within about 75 km of this epicenter was likely around April 10.

 

O:  6APR2018 07:46:58   1.4S  138.3E Mw=5.5  EMSC   NEAR N COAST OF PAPUA, INDONES

O: 06APR2018 07:46:58   1.5S  138.2E mw=5.5  ANSS   WNW of Abepura Indonesia

O: 06APR2018 07:47:02  01.5S  138.5E MS=5.4  BMG  Felt with intensity III

P: 10APR2018 115611     2.0S  139.0E 4.0-5.6 BAAAA  West Irian, PNG            

 

The strongest earthquake in the U.S. or Canada today was an M 5.2 aftershock in the Gulf of Alaska in the sequence following the M 8.0 there on January 23. This is the second strongest aftershock in the Gulf of Alaska since the immediate aftershocks of late January, 2018 which ended on January 26 with M 5.4. The only other such event since then was an M 5.4 on March 27, 2017 on the eastern end of the aftershock zone. Forecast 115495 had expected today's event was likely in late March or early April in the aftershocks zone.

 

A foreshock of M 5.4 in New Guinea at a distance of 83 degrees from the Gulf of Alaska may have helped trigger an M 5.2-5.3 in that later region which occurred 12.3 minutes after the PNG event. As it takes 12.3 minutes for the P-wave from PNG to arrive in the Gulf of Alaska, it is likely it triggered that subsequent event.

 

O:  6APR2018 20:19:03  56.0N  149.8W ML=4.1  EMSC   GULF OF ALASKA               

O:  6APR2018 20:25:39  56.1N  149.7W mb=4.6  EMSC   GULF OF ALASKA               

O:  7APR2018 03:09:10  56.2N  149.9W Mw=5.2  EMSC   GULF OF ALASKA               

P: 27MAR2018 115495    56.0N  149.0W 3.5-5.0 CAAAA  Gulf of Alaska             

 

O:  7APR2018 02:56:53   6.3S  142.7E Mw=5.3  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

P:  4APR2018 115603     6.0S  143.0E 4.0-5.5 BAAAA  Papua New Guinea           

 

A moderate earthquake of M 4.7 hit the British Virgin Islands today. It was reported felt with intensity IV in the British Virgin Islands at Road Town, Tortola and in the U.S. Virgin Islands at Saint John and Humacao, Puerto Rico. Lesser shaking of II-III was reported from the Virgin Islands at Saint Thomas, Christiansted, Frederiksted, and in Puerto Rico at Fajardo, Culebra, Luquillo, Rio Grande, Humacao, Carolina, San Juan, Trujillo Alto, Bayamon and Ponce. The last earthquake in the Virgin Islands within about 100 km of the M 4.7 today occurred April 19, 2015 with M 4.7. The last of significantly larger magnitude was an M 5.0 on January 10, 2013. Forecast 115624 had expected this event was likely around April 8 within this distance zone. This follows an M 5.0 in Guadeloupe to the south of this which occurred yesterday and was noted in this summary:

 

"NEIC reported this earthquake of M 5.0 in Guadeloupe was felt with intensity II-III in the area(s) of All Saints, Saint John, Antigua and Barbuda.'' (April 5-6, 2018)

 

O:  5APR2018 11:26:59  16.8N   61.0W mb=5.0  EMSC   GUADELOUPE REGION, LEEWARD ISL

P:  3APR2018 115624    17.0N   61.0W 3.0-5.0 AAAAA  Leeward Islands            

 

The M 4.7 in the Virgin Islands was at 143 degrees from New Britain/Ireland and at the fifth node (72 degrees) from the Gulf of Alaska and may have been  promoted by energy by recent large events in those areas.

 

O:  6APR2018 21:21:14  18.7N   64.7W Mw=4.7  EMSC   VIRGIN ISLANDS REGION        

P:  8APR2018 115624    19.0N   64.0W 3.0-5.0 AAAAA  Leeward Islands            

 

MODERATELY STRONG QUAKE SHAKES LOS ANGELES, CALIFORNIA

 

EARTHQUAKE SUMMARY FOR APRIL 5, 2018

 

A moderately strong earthquake of M 5.3-5.4 hit off the coast of Southern California today. This may be the event which this summary has been pointing to at this time being promoted at 100-102 degrees from the Papua New Guinea M 7.6 of February 25, 2018. Readers of this summary are aware that this event had been expected in late March or early April. The last earthquake of M>=5.3 within about 100 km of this epicenter occurred more than 24 years ago as an M 5.3 aftershock of the Northridge quake of M 6.7 of January 17, 1994. That aftershock occurred on March 20, 1994. In the larger area of 250 km about today's epicenter there have been three earthquakes of M>=5.3 in the past 22 years, an M 5.4 on July 29, 2008 east of Los Angeles; an M 6.0 near Parkfield on September 28, 2004 and an M 6.6 near Templeton, California about 250 km north of today's epicenter on December 22, 2003. Thus, today's earthquake is highly significant for the region. It is of particular interest then, that this earthquake had been forecast within days in this region in this summary. This was most recently noted in the April 2, 2018 summary as:

 

"The earthquake quiescence in Southern California which was noted in this summary in the last two issues appears to have come to a close today. After several events in the region of M>2 an M 3.4-3.0 southeast of Los Angeles occurred and was widely felt in the region. This summary had expected a moderate quake in this region at this time triggered by the M 7.6 in Papua New Guinea of February 25, 2018 as follows:

 

"the preponderence of evidence is that these mainshocks in New Guinea do trigger subsequent moderate to strong quakes near 103 degrees away in Southern California in the region of Los Angeles or to the east. Given the 22- to 23 year cyclicity of strong earthquakes in this area, due at this time,  this summary is placing this region under a moderate seismic watch for the next month with the most likely large quakes at the end of March. A seismic watch indicates conditions are right for  the development of significantly increased regional seismicity including  the possibility of a strong earthquake in the watch period. The watch period may be extended depending on regional activity. The most likely area would be east of Los Angeles in the general area north of of Landers, California." (February 25, 2018)

 

"As expected in the previous issue of this summary, the area east of Los Angeles was activated by energy from New Guinea. An M 3.7 in the Mountain View and Anza region  was reported by NEIC to have been widely felt in the area with light intensity" (February 26, 2018) (this earthquake occurred at 33.5N 116.5W about 25 km east of today's epicenter)

 

The seismic quiet period in southern California of the past week was also commented on in the previous issue as:

 

" ... These events (in central California) occur amid the continuing ominous total silence in Southern California of events of M>=2, a condition which may be a seismic quiescence in the region." (March 30 through April 3, 2018)

 

The M 5.3-5.4 in the Channel Islands region of California occurred within about 30 minutes of local solar noon, an hour when tidal stresses area maximized, and these may have promoted today's event as well. Regional seismicity in the Lompoc area, which has been active over the past several days, also appears to have increased following the M 5.4. A further triggered moderate quake in the area is still considered a possibility in the next week. In addition to being 101-102 degrees from PNG today's event is also at 106 degrees from the M 6.1 in Mindanao yesterday and may have been promoted from both those areas. Further activity in PNG and to the west of the February event will probably tend to bring more seismicity to Los Angeles especially if it occurs with moderate to large magnitude and seismic ping-pong begins between these two areas in the next several days before stress hardening occurs.

 

Today's event was felt within about 300 km of the epicenter in much of southern and central California. Intensity IV was reported to NEIC from the Channel Islands National Park, Oxnard, Port Hueneme, Santa Barbara, Ventura, Santa Ynez, Buellton, Fillmore, Lawndale, Inglewood and many other communities. More than 12,000 people reported to NEIC that they had felt the earthquake even though it was about 50 km south of major populated zones. Forecast 115699 had expected today's earthquake was likely at the exact computed epicenter was most likely in early April.

 

O:  5APR2018 19:29:17  33.8N  119.7W Mw=5.4  EMSC   CHANNEL ISLANDS REG., CALIFORN

P: 11APR2018 115699    33.8N  119.7W 2.5-4.7 CAAAA  So. California             

 

So, of what value was the forecast for the California earthquake, the largest in the area in the past 24 years. Evaluate this by answering the following  uestions:

 

Where else did you get more than a month's warning this event was coming?

 

Where else was the exact epicenter of this event published a week before the event occurred?

 

What other source provided this forecast and stood by it without hesitation for more than a month?

 

Where else provided adequate historical context to the activity leading up to today's event?

 

To see the complete comments prior to this earthquake readers are encouraged to revisit previous reports published here.

 

Moderately strong quakes also occurred today in Fiji (M 5.8) and in northern Chile (M 5.6). The quake in Chile was reported by NEIC to have been felt with intensity V in Iquique, Tarapaca, Chile and II-III in Arica, Antofagasta, Chile and in Mollendo, Arequipa, Peru. CSN reported this earthquake was felt with intensity VI in  Alto Hospicio, Iquique, Pisagua;  V Quillagua, IV Codpa, Cuya, Camina, La Tirana, Mamina, Pica, Tocopilla; III Arica, Huara, Ollague; II Colchane, Felt in Arica, Parinacota, Tarapaca and Antofagasts, Chile.

The last earthquake with M>=5.6 within about 150 km of this event in Chile was an M 5.8 on October 7, 2014, a year in which an M 7.6 in Tarapaca, Chile on April 3 was followed by a strong aftershock sequence through October, 2014. Forecast 115818 had expected this event within about 50 km of the epicenter was likely around April 7. This epicenter is located at 100-102 degrees from the great M 8.0 in Alaska of January 23, 2018.

 

O:  5APR2018 11:12     20.3S   70.5W mb=5.6  GUC    Alto Hospicio, Iquique, Pisagu

P:  7APR2018 115818    20.0S   71.0W 4.0-5.7 AAAAA  So. Peru/Bolivia           

 

The event of M 5.8 in Fiji was part of a series of such events in the past several days in Fiji and Tonga. These have been occurring at 103 degrees from the M 6.8 in Bolivia several days ago. These may also have been promoted by tidal stresses as noted in the seismicity forecast associated with the prior full moon:

 

"The full moon arrived on March 31 at 12:37 UT. As with the past two full moons this will affect most strongly seismicity in the Atlantic Ocean and western Europe in the west near 10W and in the east near 170E in the region from Fiji and Vanuatu south to New Zealand and in the north from Kamchatka to the Aleutians of Alaska. While these are areas most likely to see tidal promotion, increased seismicity is likely in many areas where tidal stresses are a mitigating factor." (March 29-April 4, 2018)

 

O:  5APR2018 09:07:58  18.3S  177.9W Mw=5.8  EMSC   FIJI REGION                  

P:  7APR2018 115806    19.0S  178.0W 4.0-5.5 AAAAA  Tonga Islands              

 

STRONG EARTHQUAKE IN MINDANAO, PHILIPPINES

 

EARTHQUAKE SUMMARY FOR APRIL 4, 2018

 

The strongest earthquake in the world today was an M 5.9-6.0 in Mindanao, Philippines. NEIC reported it was felt with intensity II-IV in Southern Mindanao at Canocotan, Davao and Bato, Philippines. PHIVOLCS reported it at M 6.0 felt with intensity IV in Mati City; III in Davao City; Cagayan de Oro City and General Santos City and II in Bislig City, Surigao City; Alabel and Sarangani, Philippines. The epicenter is located with 5 degrees of the geomagnetic equator in the equatorial seismic zone. This earthquake occurred within about 15 minutes of local solar noon and was probably promoted by tidal stresses which maximize at this hour. It occurred while PP-waves were at the epicenter after being created in South Island, New Zealand 14 minutes earlier. This seismic energy may have also helped promote the occurrence of the Mindanao event at the time it occurred. Likewise, an M 3.0 in Central California followed the Mindanao quake at 103 degrees from  that epicenter 18 minutes later. The PP-wave from Mindanao would have been at this subsequent California epicenter at the time of that quake. A smaller quake in Northern California 13 minutes after Mindanao was coincident with the P-wave from that Philippines event.

 

The last earthquake with M>=6.1 in Mindanao, Philippines within about 200 km of this epicenter occurred on April 28, 2017 (M 6.9) and prior to that events of M 6.3 on September 23, 2016 and July 14, 2014.

 Forecast 115580 had expected this event within about 25 km of the epicenter was likely around April 4.

 

The earthquake in New Zealand was felt in northwest South Island. GEONET reported this earthquake was felt with light intensity in the northern South Island area. There was 242 felt reports mostly from northern South Island, New Zealand. These included 158 of weak shaking. Light intensity was felt by 77 and moderate intensity by 7 person. Strong to extreme shaking was reported by none.

 

 

O: 05APR2018 03:53:40  06.8N  126.7E MS=6.0  PHI  Felt with intensity IV in Mati

O:  5APR2018 03:53:41   6.8N  126.8E Mw=6.1  EMSC   MINDANAO, PHILIPPINES        

P:  4APR2018 115580     7.0N  126.0E 4.0-5.4 AAAAA  Central Philippines        

O:  5APR2018 03:39:44  40.9S  172.2E ML=4.6  EMSC   OFF W. COAST OF S. ISLAND, N.Z

O: 05APR2017 03:39:42  40.8S  172.1E MB=4.8  GEONET Felt with light intensity in the northern South Island

P:  6APR2018 115836    42.0S  173.0E 3.0-5.3 ABAAA  So. Island, N.Z.           

 

The current swarm in the Gulf of California saw increased magnitudes today. The strongest of these were M 4.5-4.6 and were felt in the Los Cabos, Southern Baja California, Mexico region. Forecast 115642 had expected this activity was possible in the Gulf of California in early April.

 

O:  4APR2018 21:23:20  22.0N  108.6W mb=4.5  EMSC   OFF COAST OF BAJA CALIFORNIA S

O: 04APR2018 22:07:51  22.1N  108.6W ML=4.5  UNAM  al SURESTE de SAN JOSE DEL CABO, B

O: 04APR2018 21:23:24  22.3N  108.7W ML=4.6  UNAM  al SURESTE de SAN JOSE DEL CABO, B

O:  4APR2018 22:07:48  22.0N  108.7W mb=4.6  EMSC   OFF COAST OF BAJA CALIFORNIA S

P:  2APR2018 115642    24.0N  109.0W 3.5-5.1 ABAAA  Gulf of California         

 

Reports have surfaced of a giant crack 15 meters across and mile long in the East Africa Rift Valley which  apparently formed about March 19. This is part of the normal seismicity of this extensional regime. There was damage to the major highway in the region  and injuries to several people. It was probably promoted by seismic energy from Papua New Guinea where an M 7.6 earthquake occurred February 25 at a distance of 103 from these cracks and associated seismicity. This has been previously reported in this summary for example as:

 

"A moderately strong M 5.5-5.6 earthquake hit the region of Mozambique/Malawi, Africa today. NEIC reported it was felt with intensity III-IV in Blantyre City and Mulanje, Malawi. An aftershock of M 5.2 occurred about an hour later in the same area of Mozambique. This epicenter is located at 104 degrees from the activity in Papua New Guinea (PNG) of recent dates. Seismic energy from large earthquakes travels into the earth, reflects and refracts off the core-mantle boundary and returns to the surface at 103-104 degrees from the mainshock epicenter. Seismicity in this distance zone often increases following such events and is likely triggered or promoted from that energy. A series of moderate earthquakes occurred north of this early this week in the region of Tanzania at 103 degrees from PNG and were discussed in earlier issues of this report." (March 8, 2018)

 

TIDAL PROMOTION OF SEISMICITY STRONG

 

EARTHQUAKE SUMMARY FOR APRIL 3, 2018

 

Many areas appeared to see tidal promotion of seismicity today. These included area in western Europe where an M 4.3 was widely felt in Italy as well as in the southern Mid-Atlantic with M 5.3. Near the IDL three quakes occurred in

South Island, New Zealand with M 4.7-5.0; in the Kermadec Islands (M 5.2 and 4.9); in the Fiji Islands (M 4.5, 4.6) among others. This pattern matches that expected in previous issues of this summary as:

 

"The full moon arrived on March 31 at 12:37 UT. As with the past two full moons this will affect most strongly seismicity in the Atlantic Ocean and western Europe in the west near 10W and in the east near 170E in the region from Fiji and Vanuatu south to New Zealand and in the north from Kamchatka to the Aleutians of Alaska. While these are areas most likely to see tidal promotion, increased seismicity is likely in many areas where tidal stresses are a mitigating factor." (March 29-April 3, 2018)

 

The strongest earthquake in the world today was an M 5.4 in the Talaud Islands, Indonesia. BMG reported it was felt with intensity II-III in Morotai and II in Halmahera, Bitung, Kao and Siau, Maluku, Pulau, Indonesia.  PHIVOLCS noted it was felt in Philippines. Forecast 115584 had expected this event within about 100 km was likely around April 4. There has been only one other earthquake in the Talaud Islands, Indonesia in the past half year - an M 5.7 on December 28, 2017.

 

O:  3APR2018 09:14:08   3.0N  128.0E Mw=5.4  EMSC   KEPULAUAN TALAUD, INDONESIA  

O: 03APR2018 09:14:05  03.1N  127.9E MS=5.6  BMG  Felt with intensity II-III

O: 03APR2018 09:14:06  03.1N  127.9E MS=5.5  PHI  Not reported felt in Philippines.

P:  4APR2018 115584     2.0N  128.0E 4.0-5.8 AAAAA  Halmahera                  

 

The most unusual earthquake today occurred at 13 West Longitude in the Southern Mid-Atlantic Ridge. This is a remote area and the quake was not reported felt. The last earthquake within about 300 km of this epicenter of M>=5.2 occurred as an M 5.4 on April 30, 2016 and prior to that an M 5.7 on May 10, 2013.

 

O:  3APR2018 06:51:06  31.3S   13.4W mb=5.2  EMSC   SOUTHERN MID-ATLANTIC RIDGE  

O:  3APR2018 06:51:06  31.3S   13.4W mb=5.3  ANSS   SOUTHERN MID-ATLANTIC RIDGE  

 

O:  4APR2018 00:57:44  30.1S  177.7W mb=4.9  EMSC   KERMADEC ISLANDS, NEW ZEALAND

O:  4APR2018 00:48:57  30.2S  177.7W mb=5.2  EMSC   KERMADEC ISLANDS, NEW ZEALAND

P:  4APR2018 115829    30.0S  177.0W 4.0-5.4 AAAAA  No. Kermadec Islands       

 

A pair of moderate earthquakes occurred in western South Island with M 4.6 and 5.0 today.  The mainshock of M 5.0 was reported by GEONET to have been felt with light intensity in the area of north-western South Island, New Zealand. 161 people reported feeling this earthquake including 121 with weak intensity; and 35 with light intensity; 5 with moderate shaking and none with extreme intensity. GEONET the foreshock of this pair was felt with light intensity in the area of north-western South Island, New Zealand. 215 people reported feeling this earthquake including 158 with weak intensity; and 50 with light intensity; 7 with moderate shaking and none with extreme intensity. Forecast 115570 had expected this activity within about 50 km of the epicenters was likely around March 31. These events occurred within about 15 minutes of local solar noon and were probably promoted by high tidal stresses associated with the full moon which are highest at this hour. The last earthquake within about 150 km of this epicenter of M>=5 was an M 5.6 on January 5, 2015 and prior to that and M 7.0 and aftershocks on September 3-6, 2010 after a six-year quiet in the area. Like the M 6.8 in Bolivia, these epicenters are at 103 degrees from the Gulf of Alaska quake of M 8.0 of January 23 and the Mexican M 7.2 of February 16.

 

O:  3APR2018 01:12:28  43.3S  170.8E ML=4.8  EMSC   SOUTH ISLAND OF NEW ZEALAND  

O:  3APR2018 01:05:15  43.3S  170.8E ML=4.6  GEONET Felt with light intensity in t

O:  3APR2018 01:12:29  43.3S  170.8E ML=5.0  GEONET Felt with light intensity in t

P: 31MAR2018 115570    43.0S  171.0E 3.0-5.1 BAAAA  So. Island, N.Z.           

 

 

One of the areas of western Europe which has been active since the full moon is central Italy. This became active with the full moon on March 31 with an M 3.9 and has continued to produce light to moderate quakes since that time. The largest today was an M 4.3, the strongest in the area since an M 4.6 on December 3, 2017. This activity is likely to continue for several more days. Forecast 115727 had expected this event within about 10 km of the epicenter around April 2.

 

NEIC reported this earthquake of M 4.3 in Central Italy was felt with intensity II-III in the area(s) of Tolentino, Marken and Assisi, Umbria, Italy.

 

O:  4APR2018 02:19:46  43.0N   13.0E mb=4.3  EMSC   CENTRAL ITALY                

P:  2APR2018 115727    43.0N   13.0E 3.0-5.1 AAAAA  Italy                      

 

An earthquake of M 4.3 occurred in the southern Yukon Territory of Canada today. Earthquakes Canada reported this earthquake of M 4.1 in Yukon, Canada was felt with intensity II-III in the epicentral area. There were no reports of damage. The last earthquake within about 150 km of this epicenter with M>=4.3 in the Canadian Yukon occurred  September 16, 2017 with M 5.0. This epicenter is located at 101 degrees from the M 6.8 in Bolivia of April 2 and may have been promoted from that source.  Earthquakes at this same distance from Bolivia tody included a series in Tonga/Fiji. Forecasts 115776 and 115780 had expected this event within about 50 km of the epicenter in early April.

 

O:  3APR2018 16:36:38  60.4N  137.8W ML=3.8  EMSC   SOUTHERN YUKON TERRITORY, CANA

O:  3APR2018 16:36:40  60.4N  137.8W ML=4.3  EMSC   SOUTHERN YUKON TERRITORY, CANA

P:  6APR2018 115776    59.0N  138.0W 3.0-4.5 BBAAA  Southeast Alaska           

P: 10APR2018 115780    60.0N  137.0W 3.2-5.0 CAAAA  Central Alaska             

 

An earthquake of M 3.5 also occurred in Utah today.  NEIC reported this earthquake of M 3.5 in Utah was felt with intensity II-III in the area(s) of Utah at Loa, Torrey and Teasdale.  This epicenter is the largest in a swarm which has included events of M 3.0 and 3.1 on March 22, 2018. Earthquakes in Utah of M 3.6 and 3.7 occurred on February 16 and 28, 2018, the only events of M>=3.5 in the state in the past six months. Forecast 115712 had expected this activity was likely around April 4.

 

O:  3APR2018 20:26:38  38.4N  111.7W ML=3.5  EMSC   UTAH                         

P:  4APR2018 115712    38.7N  112.6W 2.0-4.2 AAAAA  Utah area                  

 

STRONG SEISMICITY MOVES WEST

 

EARTHQUAKE SUMMARY FOR APRIL 2, 2018

 

Strong earthquakes in the western hemisphere in Bolivia (M 6.8) and El Salvador (M 5.9-6.0) today appear to have been promoted by seismic energy from distant earthquakes in the southwest Pacific. In particular the event of M 6.8 in Bolivia, unprecedented in modern times, is located at 144 degrees from the epicenter of the M 7.6 in Papua New Guinea of February 25, 2018 as well as at 103 degrees from the M 6.2 earthquake and tropical cyclone Josie in the Fiji Islands which occurred yesterday. The epicenter was probably softened up by energy from the Gulf of Alaska event of M 8.0 of January 23 which is also at 103-104 degrees from Bolivia. These are distances from strong quakes at which seismic energy reflected and refracted off core and mantle boundaries is concentrated at the surface of the earth and appears to promote further seismicity. This can happen for months following the original major quakes as aftershocks and accompanying seismicity continues the propagation of seismic energy around the globe.

 

The earthquake in Bolivia had its hypocenter at a deep focus of 500-600 km. As such it was widely felt with moderate to light intensity through a wide swath of northern South America up to 1900 km from the epicenter but no damage was reported. NEIC noted intensity up to V in Asuncion, Paraguay but generally intensities were II-III. These were reported from Bolivia, Chile, Paraguay, Peru, Brazil, and Argentina. CSN reported this earthquake was felt with intensity V Chile in  Huara; III Cuya, Camina, La Tirana, Tocopilla, II Arica, Alto Hospicio, Iquique, Maria Elena, Felt in Arica, Parinacota, Tarapaca and Antofagasta, Chile. The mainshock was followed by an M 3.7 in the area of Peru where it was reported felt in Arequipa with intensity III. The last earthquake in Bolivia within  about 300 km of this epicenter with M>=6.8 occurred more than 45 years ago. Two quakes have been recorded in this area in recent history, an M 6.8 on October 25, 1973 and events of M 6.9 and 7.0 on September 23, 1887 and March 23, 1899. Forecast 115809 had expected a possibly strong quake in the area south of this in Argentina was likely in early April. The antipode of this epicenter is west of Taiwan at 21N 117E, an area where an antipodal event may be promoted.

 

O:  2APR2018 15:00:31  20.7S   63.0W mb=4.6  EMSC   CHUQUISACA, BOLIVIA          

O:  2APR2018 13:40:34  20.7S   63.1W Mw=6.8  EMSC   CHUQUISACA, BOLIVIA          

O:  2APR2018 13:40     20.7S   63.8W mb=6.8  GUC    Huara; III Cuya, Camina, La Ti

O: 02APR2018 13:40:34  20.7S   63.0W mw=6.8  ANSS   NNE of Carandayti Bolivia

P:  9APR2018 115809    24.0S   64.0W 4.0-5.6 CCAAA  Argentina                  

 

NEIC reported the earthquake in El Salvador was felt with moderate intensity. The mainshock of M 5.9-6.0 was reported by NEIC to have been felt in El Salvador with intensity V in the regions of La Paz, La Libertad, San Salvador, San Vicente, Santa Ana. It was also felt in Honduras in the areas of Intibuca, Choluteca, Tegucigalpa, and in Guatemala at Guatemala City, Sacatepequez, and Retalhulue and in Nicaragua at Managua and Tapachula, Chiapas, Mexico and in general within about 300 km of the epicenter. Moderate aftershocks of the M 5.9 were also reported felt in Antiguo Cuscatlan, La Libertad, El Salvador.

A foreshock to the southeast in Nicaragua of M 4.5 may have been felt in Coatepeque, El Salvador. The last earthquake of M>=5.9 in El Salvador was an M 7.3 southeast of today's epicenter on October 14, 2014. Forecast 115369 had expected today's event within about 25 km was likely at the end of March or early in April.

 

O: 03APR2018 01:16:18  12.8N   88.9W ML=4.3  EMSC   OFFSHORE EL SALVADOR

O: 02APR2018 23:49:49  12.8N   89.0W ML=3.7  EMSC   OFFSHORE EL SALVADOR

O: 03APR2018 01:07:00  12.9N   88.8W ML=3.8  EMSC   OFFSHORE EL SALVADOR

O: 02APR2018 23:28:19  12.9N   88.9W ML=3.8  EMSC   OFFSHORE EL SALVADOR

O: 02APR2018 23:51:00  12.9N   88.9W ML=3.8  EMSC   OFFSHORE EL SALVADOR

O: 03APR2018 00:52:19  12.9N   88.9W ML=4.2  EMSC   OFFSHORE EL SALVADOR

O: 02APR2018 23:40:54  13.0N   88.8W ML=3.9  EMSC   OFFSHORE EL SALVADOR

O: 02APR2018 23:23:19  13.1N   88.6W Mw=5.9  EMSC   OFFSHORE EL SALVADOR

O: 03APR2018 00:00:53  13.1N   88.8W ML=3.7  EMSC   OFFSHORE EL SALVADOR

O: 03APR2018 02:13:26  13.2N   88.8W ML=3.7  EMSC   OFFSHORE EL SALVADOR

O: 02APR2018 23:31:43  13.2N   88.8W ML=3.8  EMSC   OFFSHORE EL SALVADOR

O:  2APR2018 23:30:26  12.8N   88.9W ML=3.7  EMSC   OFFSHORE EL SALVADOR         

P: 26MAR2018 115369    13.0N   89.0W 3.5-5.1 CAAAA  Coast of Central America   

P: 30MAR2018 115372    13.0N   90.0W 3.5-5.4 BAAAA  Guatemala                  

 

 

A pair of moderate earthquakes occurred in western South Island with M 4.6 and 5.0 today.  The mainshock of M 5.0 was reported by GEONET to have been felt with light intensity in the area of north-western South Island, New Zealand. 161 people reported feeling this earthquake including 121 with weak intensity; and 35 with light intensity; 5 with moderate shaking and none with extreme intensity. GEONET the foreshock of this pair was felt with light intensity in the area of north-western South Island, New Zealand. 215 people reported feeling this earthquake including 158 with weak intensity; and 50 with light intensity; 7 with moderate shaking and none with extreme intensity. Forecast 115570 had expected this activity within about 50 km of the epicenters was likely around March 31. These events occurred within about 15 minutes of local solar noon and were probably promoted by high tidal stresses associated with the full moon which are highest at this hour. The last earthquake within about 150 km of this epicenter of M>=5 was an M 5.6 on January 5, 2015 and prior to that and M 7.0 and aftershocks on September 3-6, 2010 after a six-year quiet in the area. Like the M 6.8 in Bolivia, these epicenters are at 103 degrees from the Gulf of Alaska quake of M 8.0 of January 23 and the Mexican M 7.2 of February 16.

 

O:  3APR2018 01:12:28  43.3S  170.8E ML=4.8  EMSC   SOUTH ISLAND OF NEW ZEALAND  

O:  3APR2018 01:05:15  43.3S  170.8E ML=4.6  GEONET Felt with light intensity in t

O:  3APR2018 01:12:29  43.3S  170.8E ML=5.0  GEONET Felt with light intensity in t

P: 31MAR2018 115570    43.0S  171.0E 3.0-5.1 BAAAA  So. Island, N.Z.           

 

GEONET reported an M 4.6 was also felt with moderate intensity in northern South Island. 104 people reported feeling this event; 35 with weak intensity; 47 with light shaking; 20 moderate; 2 strong and none with extreme shaking. This is in northeastern South Island and was not a classic aftershock of the M 4.6 and M 5.0 about 300 km southwest of this. Forecasts 115570 and 115836 had expected these two events were likely around March 31.

 

O:  3APR2018 04:58:33  42.3S  173.8E ML=4.6  GEONET Felt with moderate intensity i

P:  6APR2018 115836    42.0S  173.0E 3.0-5.3 BAAAA  So. Island, N.Z.           

P: 31MAR2018 115570    42.0S  173.0E 3.0-5.2 BAAAA  So. Island, N.Z.           

 

 

The strongest activity in the U.S. or Canada today was a series of events of M 4.0 and 4.1 in Alaska in the Fox Islands, the Gulf of Alaska and in Southern Alaska. These are not unusual events for the region and were not felt or damaging. An earthquake of M 4.1 in the Gulf of Alaska occurred within minutes of local solar noon and may have been promoted by tidal stresses which are high at this hour.

 

O:  2APR2018 09:05:16  52.7N  168.4W ML=4.0  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

P:  7APR2018 115765    52.5N  169.2W 3.5-4.9 BAAAA  Fox Islands, Aleutians     

 

O:  3APR2018 03:46:22  56.0N  150.0W ML=4.0  EMSC   GULF OF ALASKA               

O:  2APR2018 10:09:34  56.3N  148.8W ML=4.1  EMSC   GULF OF ALASKA               

P: 27MAR2018 115495    56.0N  149.0W 3.5-5.0 BAAAA  Gulf of Alaska             

 

O:  2APR2018 08:45:31  59.9N  153.6W mb=4.1  EMSC   SOUTHERN ALASKA              

P:  5APR2018 115781    60.0N  153.5W 3.2-5.3 BAAAA  Central Alaska             

 

MODERATE QUAKE BREAKS QUIET IN SOUTHERN CALIFORNIA

 

EARTHQUAKE SUMMARY FOR APRIL 1, 2018

 

The earthquake quiescence in Southern California which was noted in this summary in the last two issues appears to have come to a close today. After several events in the region of M>2 an M 3.4-3.0 southeast of Los Angeles occurred  and was widely felt in the region. This summary had expected a moderate quake in this region at this time triggered by the M 7.6 in Papua New Guinea of February 25, 2018 as follows:

 

"the preponderence of evidence is that these mainshocks in New Guinea do trigger subsequent moderate to strong quakes near 103 degrees away in Southern California in the region of Los Angeles or to the east. Given the 22- to 23 year cyclicity of strong earthquakes in this area, due at this time,  this summary is placing this region under a moderate seismic watch for the next month with the most likely large quakes at the end of March. A seismic watch indicates conditions are right for  the development of significantly increased regional seismicity including  the possibility of a strong earthquake in the watch period. The watch period may be extended depending on regional activity. The most likely area would be east of Los Angeles in the general area north of of Landers, California." (February 25, 2018)

 

"As expected in the previous issue of this summary, the area east of Los Angeles was activated by energy from New Guinea. An M 3.7 in the Mountain View and Anza region  was reported by NEIC to have been widely felt in the area with light intensity" (February 26, 2018) (this earthquake occurred at 33.5N 116.5W about 25 km east of today's epicenter)

 

The seismic quiet period in southern California of the past week was also commented on in the previous issue as:

 

" ... These events (in central California) occur amid the continuing ominous total silence in Southern California of events of M>=2, a condition which may be a seismic quiescence in the region." (March 30 through April 1, 2018)

 

NEIC reported the M 3.7-4.0 in Southern California today was felt with intensity IV in Aguanga and Anza, California and II-III in Hemet, Pala, Temecula, Pauma Valley, Warner Springs, Winchester, Valley Center, Idyllwild, Mountain Center, Murrieta, Santa Ysabel, San Jacinto, Palm Springs, and other communities within about 100 km of the epicenter southeast of Los Angeles. Two earthquake within about 75 km of this epicenter have occurred since 2016 - the M 3.7 on February 26, 2018 and an M 4.0 south of this on December 7, 2017, the only such event in 2017. Forecasts 115697 and 115443 had expected today's activity in late March or early April, 2018.

 

O:  2APR2018 03:40:43  33.5N  116.8W ML=2.4  EMSC   SOUTHERN CALIFORNIA          

O: 02APR2018 02:53:54  33.5N  116.8W ml=3.7  ANSS   NE of Aguanga CA

O:  2APR2018 02:53:54  33.5N  116.8W ML=3.9  EMSC   SOUTHERN CALIFORNIA          

P:  3APR2018 115697    33.5N  116.7W 2.5-4.4 AAAAA  So. California             

P: 26MAR2018 115443    33.7N  116.1W 2.5-4.4 CAAAA  So. California             

 

The earthquake activation in California followed a pair of moderate events of M 4.2 and 4.3 in the Gulf of California. Earthquakes of M>=4.2 in the Gulf of California during the past half year have tended to occur north and west of these two quakes. An M 6.3 hit about 150 km northwest of this on January 19 and a series of quake in northern Baja with M 4.3-4.7 occurred in late March, 2018. Forecast 115393 expected today's activity around March 29.

 

O:  1APR2018 17:19:51  25.8N  110.0W ML=4.3  EMSC   GULF OF CALIFORNIA           

O: 01APR2018 17:19:51  25.7N  110.0W ML=4.3  UNAM  l OESTE de AHOME, SIN *: 25.76°, -

O: 01APR2018 13:27:18  25.7N  110.1W ML=4.2  UNAM  l OESTE de AHOME, SIN *: 25.74°, -

O:  1APR2018 13:27:18  25.7N  110.1W ML=4.2  EMSC   GULF OF CALIFORNIA           

P: 29MAR2018 115393    24.0N  109.0W 3.5-5.2 ABAAA  Gulf of California         

 

A moderate earthquake occurred today as an M 5.3 in Iran. NEIC reported it was felt with intensity VII in Iran at Pol-e-Zahab and V in Gilan Erab, Kermanshah, Iran. It was felt with lesser intensity in Iran at Aslamabad, Mehabad and Tehran and in Baghdad, Iraq. This continues the activation of Iran and Iraq in recent weeks. Today's quake is probably an aftershock of the M 7.3 of November 12, 2017 which hit within about 50 km of it. Forecast 115704 had expected activity in the area to the east was likely around April 2.

 

O:  1APR2018 08:35:25  34.2N   45.8E mb=5.3  EMSC   IRAN-IRAQ BORDER REGION      

P:  2APR2018 115704    34.0N   49.0E 3.8-5.2 AACAA  So. Iran                   

 

The largest earthquake in the world today was an M 6.1 in the area south of Fiji. This area had been expected in this summary to see strong tidally promoted seismicity at this time in previous issues as:

 

"The full moon will arrive on March 31 at 12:37 UT. As with the past two full moons this will affect most strongly seismicity in the Atlantic Ocean and western Europe in the west near 10W and in the east near 170E in the region from Fiji and Vanuatu south to New Zealand and in the north from Kamchatka to the Aleutians of Alaska. While these are areas most likely to see tidal promotion, increased seismicity is likely in many areas where tidal stresses are a mitigating factor." (March 31, 2018)

 

and from stresses from Tropical Cyclone Josie as:

 

 

"TC Josie formed today in the South Pacific near Fiji with winds up to 55 kts. It is expected to track to the east and south through Fiji and the Tonga Islands over the next five days. A moderate to strong earthquake in Fiji or Tonga at this would not be unlikely due to stresses from TC Josie. The area is under seismic watch through April 5. Seismic watch means conditions are right that a moderate to strong quake could occur in the watch area and time." (March 31- April 1, 2018)

 

The last earthquake of M>=6.1 within about 200 km of this epicenter in the Fiji

Islands occurred September 26, 2017, the last major quake in the area was an M 7.4 on May 23, 2013. Forecast 115820 had expected this event within about 25 km  of the epicenter was likely April 3.

 

O:  2APR2018 05:57:40  24.8S  177.2W Mw=6.1  EMSC   SOUTH OF FIJI ISLANDS        

P:  3APR2018 115820    25.0S  177.0W 4.0-5.8 AAAAA  Tonga Islands              

P: 24MAR2018 115554    24.0S  177.0W 4.0-5.6 CAAAA  Tonga Islands               

 

MARCH GOES OUT LIKE A LAMB

 

EARTHQUAKE SUMMARY FOR MARCH 31, 2018

 

Global seismicity was quiet today as the calendar transitioned from March to April. While the larger events of the day were still occurring along the geomagnetic equator, the main part of that geomagnetic promotion at the end of March appears to be concluded. It included a major New Britain event (M 7.0) and several strong events of M 6.6-6.9 along the geomagnetic equator in Indonesia and the south Pacific in late March. Seismicity in early to mid-April is likely to be relatively high due to seasonal weather changes which move crustal plate. It is normal for high seismicity to occur in late March and early to mid-April with some major events and distance triggering likely in the next two weeks. But today was quiet with no significant quakes and none which exceeded M 5.1. The largest were in Tonga/Fiji and appear to have been associated with the new Tropical Cyclone Josie which is currently making its way through that area. This summary notes:

 

"TC Josie formed today in the South Pacific near Fiji with winds up to 55 kts. It is expected to track to the east and south through Fiji and the Tonga Islands over the next five days. A moderate to strong earthquake in Fiji or Tonga

 at this would not be unlikely due to stresses from TC Josie. The area is under seismic watch through April 5. Seismic watch means conditions are right that a moderate to strong quake could occur in the watch area and time." (March 31, 2018)

 

Forecasts 115541 and 115554 had expected this activity in Tonga and Fiji in late March.

 

O: 31MAR2018 08:10:52  15.2S  173.6W mb=5.1  EMSC   TONGA                        

P: 25MAR2018 115541    16.0S  174.0W 4.0-5.4 CAAAA  Tonga Islands              

 

O: 31MAR2018 11:00:38  24.1S  179.6W mb=4.5  EMSC   SOUTH OF FIJI ISLANDS        

P: 24MAR2018 115554    24.0S  177.0W 4.0-5.6 CABAA  Tonga Islands              

 

A series of light earthquakes of M 2.5, 2.8 and 3.0 shook the area of central California south of San Francisco today. These events were reported by NEIC to have been felt with intensity II-III in California at Aromas, San Juan Bautista, Salinas, Castroville, Watsonville, Gilroy, Marina, Hollister, Seaside, Monterey, Santa Cruz, Turlock and San Francisco, California. Smaller aftershocks were felt within about 30 km of their respective epicenters. This continues regional seismicity which was felt yesterday and commented in this summary:

 

"A pair of light earthquakes of M 2.6 and 2.8 were felt today south of San Francisco, California in the region of Gilroy, California.  NEIC reported this earthquake of M 2.6 in Central California was felt with intensity II-III in the area(s) of Gilroy, San Martin, San Juan Bautista, Morgan Hill, Santa Cruz, Menlo Park, San Mateo, and San Ramon, California. The M 2.6 occurred within about an hour of local solar midnight and was probably promoted by tidal stresses which maximize near this hour. NEIC reported it was felt with intensity II-III in Gilroy and Pleasanton, California. NEIC reported the earthquake of M 2.8 in the San Francisco Bay area, California was felt with intensity II-III in the area(s) of Concord, Pleasant Hill, Walnut Creek, Martinez, Lafayette, Clayton, Moraga, Danville, San Ramon, Oakland, Castro Valley, San Francisco, San Mateo, San Carlos, Mountain View, San Jose and Gilroy, California. The last event in the San Francisco Bay area of M>=2.8 within about 50 km of today's epicenter was an M 2.8 on March 3, 2018. An M 3.3 hit near the epicenter of the M 2.6 on March 6, 2018. Forecasts 115416 and 115417 expected today's activity at the end of March. These events occur amid the continuing ominous total silence in Southern California of events of M>=2, a condition which may be a seismic quiescence in the region." (March 30-31, 2018)

 

Forecasts 115414 and 115416 had expected this activity in Central California was likely in late March within about 50 km of these epicenters.

 

O: 31MAR2018 15:12:11  36.9N  121.6W MD=2.4  EMSC   CENTRAL CALIFORNIA           

O: 31MAR2018 15:07:31  36.9N  121.6W MD=2.8  EMSC   CENTRAL CALIFORNIA           

P: 25MAR2018 115416    37.3N  121.6W 2.5-4.6 CAAAA  Central California         

 

O: 31MAR2018 14:33:39  36.9N  121.6W ML=3.0  EMSC   CENTRAL CALIFORNIA           

P: 31MAR2018 115414    36.6N  120.7W 2.5-4.8 AAAAA  Central California         

 

The strongest seismicity in the U.S. or Canada today continued in the Gulf of Alaska where an M 4.4 was recorded. This is typical aftershocks activity following the M 8.0 in the area on January 23, 2018. It had been expected  in late March in forecast 115495.

 

O:  1APR2018 04:38:53  55.9N  149.3W mb=3.8  EMSC   GULF OF ALASKA               

O:  1APR2018 01:40:53  56.2N  149.2W mb=4.4  EMSC   GULF OF ALASKA               

P: 27MAR2018 115495    56.0N  149.0W 3.5-5.0 BAAAA  Gulf of Alaska             

 

 

 

FULL MOON MAY BRING TIDAL PROMOTION OF SEISMICITY TODAY

 

EARTHQUAKE SUMMARY FOR MARCH 30, 2018

 

The strongest earthquake of the day was an M 5.1 in the Kermadec Islands, New Zealand. Another quake of M 5.1 also occurred near the IDL in the region of Tonga/Samoa and in Seram, Indonesia. These were probably promoted by the previous geomagnetic storm and the upcoming full moon which arrives today as noted in this and previous issues of this summary:

 

"The full moon will arrive on March 31 at 12:37 UT. As with the past two full moons this will affect most strongly seismicity in the Atlantic Ocean and western Europe in the west near 10W and in the east near 170E in the region from Fiji and Vanuatu south to New Zealand and in the north from Kamchatka to the Aleutians of Alaska. While these are areas most likely to see tidal promotion, increased seismicity is likely in many areas where tidal stresses are a mitigating factor." (March 29-31, 2018)

 

Forecast 115562 had expected this event within about 100 km of this epicenter was likely around March 31.

 

O: 31MAR2018 06:31:12  30.5S  177.7W mb=5.1  EMSC   KERMADEC ISLANDS, NEW ZEALAND

P: 31MAR2018 115562    30.0S  179.0W 4.0-5.4 AAAAA  No. Kermadec Islands       

 

O: 31MAR2018 08:10:52  15.2S  173.6W mb=5.1  EMSC   TONGA                        

P: 25MAR2018 115541    16.0S  174.0W 4.0-5.4 CAAAA  Tonga Islands              

P: 26MAR2018 115534    15.0S  176.0W 4.0-5.4 BABAA  Samoa Islands              

 

O: 30MAR2018 07:01:13   3.4S  130.9E mb=5.1  EMSC   SERAM, INDONESIA             

P: 29MAR2018 115345     3.0S  128.0E 4.0-5.4 AACAA  Ceram area                 

 

A light earthquake in eastern Turkey today was felt with moderate intensity. EMSC reported this earthquake of M 3.5 in Eastern Turkey was felt with intensity II-III in the area(s) of Otlukbeli, Tercan and Erzincan, Turkey.  This event is in the area where a moderate to large quake may be triggered by energy from Papua New Guinea (PNG) where a major M 7.6 quake occurred February 25. It is located at 103 degrees from PNG, a distance at which seismic energy is concentrated on the surface following major earthquakes. The area of Erzincan has seen major earthquakes before and may be due for another.

 

O: 31MAR2018 06:33:35  40.0N   40.0E ML=3.5  EMSC   EASTERN TURKEY               

P: 28MAR2018 115458    40.0N   41.0E 3.5-5.1 BAAAA  Caucasus/Caspian Sea       

 

Two other notable earthquakes in Europe occurred today - an M 3.8 also in  eastern Europe but southwest of the Erzincan quake and an M 3.9 in Central

Italy. The event in Italy was widely felt in the region of L’Aquila where a series of strong quakes did considerable damage and loss of life in October, 2016 and again in January, 2017 with maximum event of M 6.6 on October 30, 2016. The last aftershock within about 100 km of this epicenter with M>=4.1 occurred December 3, 2017 and the last of larger magnitude was an M 4.3 on July 1, 2017.

EMSC reported this earthquake of M 3.9 in Central Italy was felt with intensity II-III in the area(s) of Paganica, L'Aquila, Tempera, Assergi, Cominio, Ocre, Coppito, Arischia, Preturo and Sassa among others within about 50 km of the epicenter. Forecast 115463 had expected today's event was likely within about 50 km of this epicenter around March 30.

 

O: 30MAR2018 21:05:36  38.4N   39.1E ML=3.8  EMSC   EASTERN TURKEY               

P: 27MAR2018 115452    39.0N   40.0E 3.5-5.2 BAAAA  Turkey                     

 

O: 31MAR2018 01:18:44  42.4N   13.5E ML=3.9  EMSC   CENTRAL ITALY                

P: 30MAR2018 115463    43.0N   14.0E 3.0-5.5 AAAAA  Italy                      

 

A pair of light earthquakes of M 2.6 and 2.8 were felt today south of San Francisco, California in the region of Gilroy, California.  NEIC reported this earthquake of M 2.6 in Central California was felt with intensity II-III in the area(s) of Gilroy, San Martin, San Juan Bautista, Morgan Hill, Santa Cruz, Menlo Park, San Mateo, and San Ramon, California.  The M 2.6 occurred within about an hour of local solar midnight and was probably promoted by tidal stresses which maximize near this hour. NEIC reported it was felt with intensity II-III in Gilroy and Pleasanton, California. NEIC reported the earthquake of M 2.8 in the San Francisco Bay area, California was felt with intensity II-III in the area(s) of Concord, Pleasant Hill, Walnut Creek, Martinez, Lafayette, Clayton, Moraga, Danville, San Ramon, Oakland, Castro Valley, San Francisco, San Mateo, San Carlos, Mountain View, San Jose and Gilroy, California. The last event in the San Francisco Bay area of M>=2.8 within about 50 km of today's epicenter was an M 2.8 on March 3, 2018. An M 3.3 hit near the epicenter of the M 2.6 on March 6, 2018. Forecasts 115416 and 115417 expected today's activity at the end of March. These events occur amid the continuing ominous total silence in Southern California of events of M>=2, a condition which may be a seismic quiescence in the region.

 

O: 31MAR2018 09:05:53  37.1N  121.5W MD=2.6  EMSC   NORTHERN CALIFORNIA          

P: 25MAR2018 115416    37.3N  121.6W 2.5-4.6 AAAAA  Central California         

 

O: 30MAR2018 15:05:39  38.0N  122.1W MD=2.8  EMSC   SAN FRANCISCO BAY AREA, CALIF.

P: 29MAR2018 115417    37.9N  122.0W 2.5-4.7 AAAAA  Central California         

 

While the largest earthquake in the U.S. or Canada today remained in the Gulf of Alaska (M 4.3), it was not reported felt. An M 4.1 in Southern Alaska was widely felt.  NEIC reported this earthquake of M 4.1 in Central Alaska was felt with intensity II-III in the area(s) of Wasilla, Willow, Elmendorf AFB, Fort Richardson, Chugiak, Anchorage, Eagle River, Palmer and Cooper Landing, Alaska.  This is not a common epicenter. The last event within about 100 km of this with M>=4.1 was an M 4.1 on April 26, 2017 nearly a year ago. An M 4.3 hit about 150 km east of this on January 26, 2018.  Forecast 115516 expected this earthquake within about 150 km around March 30.

 

O: 30MAR2018 11:36:00  61.6N  150.0W ML=4.1  EMSC   SOUTHERN ALASKA              

P: 30MAR2018 115516    60.1N  150.6W 3.2-5.3 ABAAA  Central Alaska              

 

O: 31MAR2018 01:07:50  56.0N  149.8W ML=4.3  EMSC   GULF OF ALASKA               

P: 27MAR2018 115495    56.0N  149.0W 3.5-5.0 BAAAA  Gulf of Alaska             

 

MAJOR QUAKE SHAKES NEW BRITAIN

 

EARTHQUAKE SUMMARY FOR MARCH 29, 2018

 

A major earthquake of M 7.0 occurred near the geomagnetic equator today in the region of New Britain. This summary had expected a larger quake in this area

was likely as noted in previous issues:

 

"A second mainshock hit this area of New Britain with M 6.3 at the beginning of the current global seismic activation on March 24, 2018. The last earthquake with M>=6.6 within about 200 km of today's epicenter was an M 7.5 on May 5, 2015 after a series of strong but smaller events on April 30-May 1, 2015. Similar conditions may be setting up at this time." (March 26-27, 2018)

 

The M 7.0 in New Britain as well as an earlier M 5.8 in the Solomon Islands about 2.5 hours prior were probably part of the geomagnetic activation of seismicity near the geomagnetic equator as previously described in this summary:

 

"Global seismicity, especially at about 10-15 degrees from the geomagnetic equator and at auroral high latitudes is expected to be high during the period March 29-31 due to this storm.  Another major earthquake is still possible towards the end of March perhaps in combination with other seismic promotion factors." (March 28-29, 2018)

 

The earthquake of M 7.0 in New Britain was reported with intensity IX in the epicentral area and VIII in Kimbe, West New Britain. Lesser shaking of V was felt in Kokopo and Rabaul, East New Britain and at Port Moresby, Papua New Guinea.   Moderate aftershocks of M 5.1 and 5.3 were also lightly felt. This is the strongest earthquake in the world in the past month since the M 7.6 in Papua New Guinea of February 25. The last earthquake in New Britain within about 200 km of this epicenter with M>=7 occurred on May 5, 2015 (M 7.5) and prior to that as an M 7.5 on March 29, 2015. A pair of events of M 7.3 and 7.0 also hit the area in summer, 2010. The last great earthquakes in New Britain occurred on November 16 and 17, 2000 with M 8.0 and 7.8. Forecast 115350 expected this quake in New Britain was likely at the end of March within about 150 km of the epicenter.

 

O: 29MAR2018 07:31:00   5.4S  150.8E Mw=5.0  EMSC   NEW BRITAIN REGION, P.N.G.

O: 29MAR2018 21:25:38   5.5S  151.5E Mw=7.0  EMSC   NEW BRITAIN REGION, P.N.G.

O: 29MAR2018 21:38:37   5.5S  151.6E mb=5.3  EMSC   NEW BRITAIN REGION, P.N.G.

O: 29MAR2018 21:49:59   5.6S  151.6E mb=5.1  EMSC   NEW BRITAIN REGION, P.N.G.

O: 29MAR2018 22:15:30   5.7S  151.5E mb=5.0  EMSC   NEW BRITAIN REGION, P.N.G.

O: 29MAR2018 22:51:26   6.0S  151.9E mb=5.3  EMSC   NEW BRITAIN REGION, P.N.G.   

P: 23MAR2018 115350     5.0S  153.0E 4.0-5.6 CAAAA  New Britain                

 

Also, as noted in previous summaries, the 103 degree line from New Britain

passes through western Mexico and Oklahoma through the East Pacific Rise, Madagascar the Gulf of Aden and Iran/Iraq while the eastern Caribbean and Spain are near 144 degrees from New Britain. These areas have been showing seismicity likely promoted by large but smaller events in New Britain over the past several days and this can be expected to expand and intensify in the next week. Southern California is at the fourth node from New Britain (90 degrees) and could also see some increases in the current low level of regional seismicity. Another event near the fourth node from New Britain is Tajikistan where an M 5.7 occurred about an hour-and-a-half after that quake and was likely promoted by energy from the earthquake in New Britain.  The last earthquake in Tajikistan within 200 km of today's event of M>=5.7 occurred on May 3 and 5, 2017 with M 6.0 and 5.8 and prior to that on May 12, 2012 with M 5.7-5.9. Forecast 115423 had expected activity in this area around March 29.

 

O: 29MAR2018 23:24:43  38.7N   69.9E mb=4.7  EMSC   TAJIKISTAN                   

O: 29MAR2018 22:54:13  38.7N   70.0E mb=5.7  EMSC   TAJIKISTAN                   

P: 29MAR2018 115423    36.0N   72.0E 3.8-5.6 ACBAA  Hindu Kush/Pakistan        

 

The earthquake of M 5.8 in the southeastern Solomon Islands was also part of the geomagnetic activation of seismicity near the geomagnetic equator. NEIC reported it was felt with intensity IV in Honiara, Guadalcanal, Solomon Islands. The last earthquake in the Southeastern Solomon Islands with M>=5.8 was an M 6.0 on March 19, 2017 and prior to that as an M 6.0 on September 14, 2014. Forecasts 115533 and 115358 had expected this activity in the Solomon Islands was likely as a moderately strong quake at the end of March.

 

O: 29MAR2018 18:51:09   9.4S  159.6E Mw=5.8  EMSC   SOLOMON ISLANDS              

P: 22MAR2018 115533    10.0S  161.0E 4.0-5.5 CABAA  No. of Santa Cruz Islands  

P: 25MAR2018 115358     8.0S  156.0E 4.0-5.5 BBCAA  Solomon Islands            

 

The strongest activity in the U.S. or Canada today remained in the Gulf of Alaska as aftershocks of the M 5.4 on the eastern end of the zone. The strongest of these was M 4.5. It was accompanied by shocks of M 4.0, 4.2 and  4.3. Forecast 115495 had expected this earthquake was likely within about 50 km of the epicenters around March 27.

  

O: 29MAR2018 20:12:07  56.3N  148.6W mb=4.2  EMSC   GULF OF ALASKA

O: 29MAR2018 20:52:35  56.3N  149.2W ML=4.0  EMSC   GULF OF ALASKA

O: 29MAR2018 19:48:29  56.5N  148.7W mb=4.3  EMSC   GULF OF ALASKA

O: 29MAR2018 14:38:13  56.6N  148.6W ML=3.1  EMSC   GULF OF ALASKA

O: 29MAR2018 19:19:22  56.7N  148.5W mb=4.5  EMSC   GULF OF ALASKA               

P: 27MAR2018 115495    56.0N  149.0W 3.5-5.0 AAAAA  Gulf of Alaska             

 

GEOMAGNETIC PROMOTION OF SEISMICITY CONTINUES

 

EARTHQUAKE SUMMARY FOR MARCH 28, 2018

 

Most of the moderate seismicity in the world today occurred within 10-15 degrees  of the geomagnetic equator. This was the pattern expected at this time from promotion of seismicity due to geomagnetic effects as noted in previous issues of this summary:

 

"Global seismicity, especially at about 10-15 degrees from the geomagnetic equator and at auroral high latitudes is expected to be high during the period March 23-27 due to this storm. A major earthquake still appears likely towards the end of March." (March 23, 2018)

 

While the maximum magnitude in global earthquakes today was M 5.0. The four  events of this size in the Tanimbar Island, New Britain, Solomon Islands and New Guinea all occurred within about 10-15 degrees of the geomagnetic equator. None of these events were reported felt and all were forecast within about 100 km of the epicenters in the South Pacific and Indonesia.

 

O: 28MAR2018 18:34:18   6.7S  131.7E mb=5.0  EMSC   KEP. TANIMBAR REGION, INDONESI

P: 18MAR2018 115092     7.0S  131.0E 4.0-5.4 CAAAA  West Irian, PNG            

 

O: 29MAR2018 07:31:00   5.4S  150.8E Mw=5.0  EMSC   NEW BRITAIN REGION, P.N.G.   

P: 22MAR2018 115351     5.0S  150.0E 4.0-5.5 CAAAA  New Ireland                

 

O: 28MAR2018 23:45:42  10.2S  161.6E mb=5.0  EMSC   SOLOMON ISLANDS              

P: 22MAR2018 115533    10.0S  161.0E 4.0-5.5 CAAAA  No. of Santa Cruz Islands  

 

O: 29MAR2018 02:40:23   6.2S  142.6E mb=4.7  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O: 28MAR2018 18:50:04   6.3S  143.0E mb=5.0  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

P: 28MAR2018 115354     6.0S  143.0E 4.0-5.6 AAAAA  Papua New Guinea           

 

The most unusual earthquake of the day was an M 4.2 in the Gujarat, India aftershock zone. NEIC reported this earthquake of M 4.2 in Gujarat, India was felt with intensity IV in Gujarat at Bhachau, Gandhi Dham, Anjar, Morvi, Bhuj, Jamnagar, and II-III in the area(s) of Rojkot, Bhayavadar and Bangalore, Kamataka, India. The last earthquake in this area within about 200 km of today's epicenter with M>=4.2 was an M 4.2 on October 6, 2015 and before than an M 4.5 on March 7, 2013. A major quake on January 26, 2001 of M 7.7 did major damage with great loss of life in the Gujarat area. Today's event appears to be an aftershock of that earthquake. Forecast 115396 had expected this earthquake within about 50 km was likely around March 26. 

 

O: 28MAR2018 22:33:08  23.2N   70.5E mb=4.2  EMSC   GUJARAT, INDIA               

P: 26MAR2018 115396    23.0N   71.0E 3.5-5.1 AAAAA  India                      

 

A swarm of light earthquakes which has been ongoing for days continued in and near the region southeast of Los Angeles, California today. These events in the Borrego Springs area of Southern California have not been felt but could suggest the possible future site of a regionally significant earthquake. The area is at 103 degrees from the PNG epicenter of February 25 and could have been promoted by energy from that source concentrated on the surface by reflections and refractions off the core-mantle boundary. There have been  moderate quakes at this distance in the past week in the Baja California area of M 4.5 and 4.7 in northern Baja, but no moderate earthquakes within southern California have occurred - yet. Stress may have been preferentially propagated to the west of the PNG epicenter and resulted in the series of moderately large and unusual events in east Africa over the past month. There have been enough unusual and moderate quakes at 103 degrees from PNG in the western U.S. and Mexico, however, that some triggering in that area apparently has been  occurring. The period of predictable triggering in this area will be coming to an end in the next week or two for areas near rupture. Strong quakes in New Ireland and New Britain may have reset the most likely zones of triggered activity to the east as well.

 

GULF OF ALASKA; PAPUA NEW GUINEA STILL AFFECT GLOBAL SEISMICITY

 

EARTHQUAKE SUMMARY FOR MARCH 27, 2018

 

It has been a month (30 days) since the M 7.6 in Papua New Guinea of February 25

and two months since the M 8.0 in the Gulf of Alaska of January 23, 2018. But despite this promotion of seismicity from both these earthquakes appears to be  continuing albeit at a lower magnitude level. The strongest and most unusual earthquakes of the day occurred as an M 5.4 aftershock in the Gulf of Alaska and as an M 4.9 in the Azores. The Azores earthquake is at 144 degrees from the M 7.6 in Papua New Guinea as well as 144 degrees from the New Britain quakes of March 26, a distance at which strong concentration of seismic energy occurs following strong earthquakes. The M 5.4 in the Gulf of Alaska is the strongest aftershock of the M 8.0 to date since the immediate aftershocks of January 23 and 24. The largest aftershock in the area in the past two months had been an M 5.1 on January 31. Neither event was reported felt.

 

The event in the Gulf of Alaska of M 5.4 is on the eastern edge of the aftershock zone. Forecast 115495 had expected it was likely around March 27 within about 50 km of this epicenter.  It was not reported felt in this remote region.

 

O: 28MAR2018 02:49:41  56.3N  149.3W Ml=3.3  EMSC   GULF OF ALASKA

O: 27MAR2018 09:48:48  56.4N  148.5W ML=3.5  EMSC   GULF OF ALASKA

O: 27MAR2018 23:09:14  56.4N  148.6W ML=3.1  EMSC   GULF OF ALASKA

O: 27MAR2018 19:40:24  56.5N  148.7W ML=4.0  EMSC   GULF OF ALASKA

O: 27MAR2018 11:51:22  56.6N  148.7W Ml=3.6  EMSC   GULF OF ALASKA

O: 27MAR2018 22:16:18  56.6N  148.7W mb=4.4  EMSC   GULF OF ALASKA

O: 27MAR2018 20:51:44  56.5N  148.7W mb=3.8  EMSC   GULF OF ALASKA

O: 27MAR2018 22:41:09  56.6N  148.6W Mw=5.4  EMSC   GULF OF ALASKA

O: 27MAR2018 22:41:08  56.5N  148.6W mw=5.4  ANSS   ESE of Kodiak Alaska

O: 27MAR2018 20:12:01  56.7N  148.7W Ml=3.4  EMSC   GULF OF ALASKA               

P: 27MAR2018 115495    56.0N  149.0W 3.5-5.0 AAAAA  Gulf of Alaska             

 

The earthquake of M 4.9 in the northern Azores at 144 degrees from PNG today was also somewhat unusual. Although the Azores often see small to lightly moderate quakes, events of M>=4.9 are not common. The last earthquake within about 100 km of today's epicenter with M>=4.9 occurred on July 14, 2016 with M 5.2 and prior to that on May 26, 2014 also with M 5.2. The strongest activity in the Azores in the past 10 years has been events of M 5.4 on May 24, 2008 and an M 5.6 about 150 km to the south of today's epicenter on August 30, 2017.  Forecast 115474 had expected today's event within about 50 km was likely around March 24.

 

O: 28MAR2018 00:58:04  41.1N   29.5W mb=4.9  EMSC   AZORES ISLANDS REGION        

P: 24MAR2018 115474    41.0N   30.0W 4.0-5.6 BAAAA  No. Mid-Atlantic Ridge     

 

One of the most distinct triggering patterns of the month following the PNG quake was a series of moderately strong, and unusual, earthquakes at 103 degrees  from that mainshock. This has included, to date, moderately large quakes in Ethiopia, Tanzania, Mozambique and Malawi and to a lesser extent in western U.S. This pattern also continued today with a swarm along the Iran-Iraq border. These may, however, be better defined as promoted from the strong New Britain quakes of the past two days which lie at 102 degrees from the Iranian epicenters. Smaller events at this distance from PNG also occurred today in eastern Turkey and the Caucasus.

 

NEIC reported the earthquake of M 4.4 in Iran was felt with intensity II-III in the area(s) of Ahwaz, Khuzestan, Iran.

 

O: 27MAR2018 23:55:12  31.8N   48.8E mb=4.3  EMSC   WESTERN IRAN                 

O: 27MAR2018 23:07:55  31.8N   48.8E mb=4.4  EMSC   WESTERN IRAN                 

P: 15MAR2018 115186    31.0N   50.0E 3.8-5.3 DAAAA  So. Iran                    

P: 25MAR2018 115447    30.0N   51.0E 3.8-5.4 ABBAA  So. Iran                   

 

NEIC reported the earthquake of M 4.4 in Iraq was felt with intensity IV in the area(s) of Kefri, Iraq.

 

O: 28MAR2018 00:27:07  34.3N   45.4E mb=4.4  EMSC   IRAN-IRAQ BORDER REGION      

O: 28MAR2018 01:55:31  34.5N   45.4E ML=3.6  EMSC   IRAN-IRAQ BORDER REGION      

O: 28MAR2018 01:19:23  34.6N   45.6E ML=3.7  EMSC   IRAN-IRAQ BORDER REGION      

P: 22MAR2018 115447    34.0N   49.0E 3.8-5.4 CACAA  So. Iran                    

 

O: 28MAR2018 02:12:34  38.7N   43.2E ML=3.1  EMSC   EASTERN TURKEY               

P: 26MAR2018 115452    38.0N   44.0E 3.5-5.3 AAAAA  Turkey                     

 

Likewise, the largest earthquake in the vicinity North America outside Alaska today was an M 4.2 in the area off the coast of southern Baja California.  It was not reported felt but occurred at 102 degrees from the M 6.6 in New Britain yesterday, a distance at which triggering is deemed likely by this summary. This is the strongest earthquake within about 150 km of this epicenter since May 3, 2012 when an M 4.2 and 5.6 occurred east of this epicenter. Forecast 115393 had expected this event within about 100 km of this epicenter was likely at the end of March.

 

O: 28MAR2018 07:50:33  21.3N  109.2W ML=4.2  EMSC   OFF COAST OF BAJA CALIFORNIA S

P: 22MAR2018 115393    20.0N  109.0W 3.5-5.1 CBAAA  Gulf of California         

 

STRONG QUAKE IN NEW BRITAIN CONTINUES GLOBAL ACTIVATION

 

EARTHQUAKE SUMMARY FOR MARCH 26, 2018

 

A strong aftershock in the region of New Britain occurred today with M 6.6. NEIC reported it was felt with intensity V in Kokopo; IV in Rabaul and II-III in Kimbe and Port Moresby, Papua New Guinea. This continues the strong global activation of seismicity which began two days ago after nearly a month of quiet conditions. It is likely it was promoted by the geomagnetic storm now winding down. Most of the strong and moderately strong quakes in this series have occurred, like today's within about 10-15 degrees of the geomagnetic equator, a pattern that had been expected in previous issues of this summary as:

 

"Global seismicity, especially at about 10-15 degrees from the geomagnetic equator and at auroral high latitudes is expected to be high during the period March 23-27 due to this storm. A major earthquake still appears likely towards the end of March." (March 23, 2018)

 

A second mainshock hit this area of New Britain with M 6.3 at the beginning of the current global seismic activation on March 24, 2018. The last earthquake with M>=6.6 within about 200 km of today's epicenter was an M 7.5 on May 5, 2015 after a series of strong but smaller events on April 30-May 1, 2015. Similar conditions may be setting up at this time.

 

Forecast 115351 expected this activity was likely in late March.

 

O: 26MAR2018 09:51:01   5.5S  151.3E Mw=6.6  EMSC   NEW BRITAIN REGION, P.N.G.   

O: 26MAR2018 09:51:00   5.5S  151.4E mw=6.6  ANSS   Kimbe Papua New Guinea

P: 22MAR2018 115351     5.0S  150.0E 4.0-5.5 BAAAA  New Ireland                

 

A small earthquake of M 2.2 occurred in eastern Maine today. This occurred within  about 15 minutes of local solar midnight and was probably promoted by tidal stresses. It was not reported felt in this epicentral area. This is the strongest earthquake in east-central Maine within about 50 km of this epicenter since an swarm including an M 4.4 on February 8-9, 2016.

 

Forecast 115467 had expected this area would be active in late March.

 

 

O: 27MAR2018 04:52:46  45.5N   67.3W ML=2.2  EMSC   MAINE                        

P: 22MAR2018 115467    44.4N   68.2W 2.0-4.3 BBAAA  Maine                      

 

STRONG BANDA SEA EARTHQUAKE WIDELY FELT

 

EARTHQUAKE SUMMARY FOR MARCH 25, 2018

 

A strong M 6.6 (EMSC) - 6.9 (BMG) earthquake hit the Banda Sea, Indonesia today. This is part of a global activation begun yesterday with strong earthquakes in the Indian Ocean and New Britain of M 6.3 and a series of moderately strong quakes in other regions over the past two days. Moderately large earthquakes of M 5.6-5.7 also shook regions of southeastern Japan in the Izu Islands and Argentina. The event in the Izu Islands occurred about 9 minutes after the Argentinian earthquake. Both may have been promoted by similar processes. Although these two epicenters are nearly antipodal, nine minutes is not enough time for seismic waves to reach the second epicenter, so direct triggering by seismic waves is not possible in this case.

 

The M 6.6 was reported by NEIC to have been felt with intensity III in East Timor at Baucau and Dili and in Northern Territory, Australia with III-IV in Coonawarra, Palmerston, Darwin, Howard Springs, Humpty-Doo-MacMinns Lagoo, Maningrida, and Katherine and in Kununurra, Wester Australia. BMG reported it was felt in Indonesia with intensity III-IV in Saumlaki; III in Sorong and Kaimana, Maluku, Indonesia. The regional foreshock of M 5.6 was also reported felt with intensity II-III in Northern Territory, Australia at Coonawarra, Darwin and Humpty Doo-MacMinns Lagoon. Earthquakes in the Banda Sea often shake northern Australia due to local conditions and the deep focus of the Banda Sea events. The last moderately strong quake in the Banda Sea other than today's foreshock of M 5.5 occurred on March 2, 2018 with M 5.9. At the time this summary noted:

 

"A series of moderate foreshocks in Banda occurred yesterday as well. This area is at 11 degrees from PNG and was probably promoted by stress redistribution associated with that quake.  The last earthquake of M>=5.9 in the Banda Sea within about 200 km of this epicenter was an M 6.9 more than two years ago on December 9, 2015 about 250 km to the northwest and an M 6.1 on November 21, 2015 about 100 km to the south. NEIC reported this earthquake of M 5.9 in Banda was felt with intensity II-III in the area(s) of Northern Territory, Australia at Darwin and Howard Springs. Earthquakes in the Banda Sea are often felt lightly in Australia's Northern Territory. Forecast 114816 had expected this event about 100 km southwest of this epicenter was likely around March 4. The Banda Sea quake was followed about 40 minutes later by the strongest aftershock of the day in the New Guinea area, an event which was probably promoted from the Banda Sea area.  It was reported felt in Kiunga, Fly River, Papua New Guinea with intensity III. This event occurred within about 30 minutes of local solar noon and was probably also promoted by high tidal stresses associated with the full moon today. The Banda Sea quake was also located at exactly (90.0 degrees) the fourth node from the great quake in the Gulf of Alaska of January 23 and may have been set up by energy from that event as well." (March 2, 2018)

 

 

The Banda Sea is no stranger to strong earthquakes. Most of the events since 2000 of M>=6.6 have occurred in the winter, usually in December or January although in the 1990's this pattern included two earthquake in October and November, the only such event outside winter in the past 18 years (besides today's) was an 6.9 on October 24, 2009, the other seven events at this magnitude in the Banda Sea all occurred in winter. This may be related to loading from ocean waters which reaches maximum during this season. The last earthquakes in the Banda Sea of M>=6.6 occurred on December 21, 2016 (M 6.7); December 9, 2015 (M 6.9) and December 10, 2012 (M 7.1). 

 

This summary had noted increased activity in the Banda Sea in recent days, perhaps related to the PNG M 7.6 of February 25. This was generally associated with Tropical Storm Nora which passed south and east of the Banda Sea in recent days and was expected, in this summary, to have notable effects on regional seismicity as per example:

 

"TC Nora continued today south of Papua New Guinea and north of Australia with winds up to 50 kts. It is expected to stay in this general area for several more days before turning south into Australia. New Guinea to the north is a seismic region where strong aftershocks of the February 25 event could be promoted by stresses from TC Nora. The antipode is at 12N 40W in the central mid-Atlantic region where a moderate earthquake could be promoted from antipodal focusing from Nora. This earthquake occurred with M 5.2 on March 22." (March 24, 2018)

 

Today's earthquake in the Banda Sea is also likely to have promoted by the now concluded geomagnetic storm. The epicenter lies about 10-15 degrees south of the local geomagnetic equator. This summary had noted this possibility as:

 

 

"Global seismicity, especially at about 10-15 degrees from the geomagnetic equator and at auroral high latitudes is expected to be high during the period March 23-27 due to this storm. A major earthquake still appears likely towards the end of March." (March 23, 2018)

 

Forecast 115342 had expected this activity in the Banda Sea within about 150 km of these epicenters was likely around March 25.

 

O: 25MAR2018 20:14:47   6.7S  129.7E Mw=6.6  EMSC   BANDA SEA                    

O: 25MAR2018 15:24:29   6.9S  129.3E mb=4.5  EMSC   BANDA SEA                    

O: 25MAR2018 08:58:12   7.4S  128.5E Mw=5.6  EMSC   KEPULAUAN BARAT DAYA, INDONESI

O: 26MAR2018 20:14:47  06.8S  129.8E MS=6.9  BMG    Felt with intensity III-IV

P: 25MAR2018 115342     7.0S  128.0E 4.0-5.6 AAAAA  Banda Sea                  

 

The antipode of Nora also showed significant activity today. An earthquake of M 4.9 at 8N 38W and a second of M 4.7 were in the antipodal area of Nora and were probably promoted by energy from that storm which focused at the antipode. These events are also at the antipode of the M 7.6 in Papua New Guinea of  February 25, 2018 (compare 8N and 6S 142E and 38W as antipodes) in an area where triggered activity from that region was expected in this summary at the time. Forecast 115329 had expected this activity was likely within about 100 km of this epicenter around March 29. The last event within about 200 km of this epicenter was an M 4.9 on November 16, 2017 and prior to that an M 4.9

on February 21, 2016.

 

O: 25MAR2018 18:23:07   8.1N   38.1W mb=4.7  EMSC   CENTRAL MID-ATLANTIC RIDGE   

O: 25MAR2018 11:11:52   8.1N   38.1W mb=4.9  EMSC   CENTRAL MID-ATLANTIC RIDGE   

P: 29MAR2018 115329     8.0N   37.0W 4.0-5.9 BAAAA  Central Mid-Atlantic Ridg  

 

A moderately strong earthquake in the Izu Islands, Japan of M 5.7 today was widely felt in the region. NEIC reported this earthquake of M 5.7 in Southeastern Japan was felt with intensity II-III in the area(s) of Kanagawa, Chiba, Shizuoka, Tokyo, Saitama, Miyagi, Japan. This followed a deep focus M 5.6 in Argentina nine minutes earlier which was not felt. The Izu Islands quake was followed an hour later by an M 5.0. The most recent earthquake in this area of the Izu Islands of M>=5.7 was an M 5.8 on November 16, 2017, an aftershock of an M 6.0 on November 9. Forecast 115436 had expected today's event south of these epicenters was likely around March 26.

 

O: 25MAR2018 15:36:23  32.5N  140.9E mb=5.0  EMSC   IZU ISLANDS, JAPAN REGION    

O: 25MAR2018 14:37:23  32.6N  140.8E Mw=5.7  EMSC   IZU ISLANDS, JAPAN REGION    

P: 26MAR2018 115436    31.0N  140.0E 4.0-5.6 ABAAA  Off East Coast Honshu      

 

The M 5.6 in Argentina was not reported felt. For a deep focus quake of this magnitude, this is not surprising. Any shaking would have been on the edge of being felt on the surface 500+ km from the hypocenter. The last earthquake within about 250 km of this epicenter with M>=5.6 was a shallow focus M 5.9 on October 17, 2015 and prior to that an M 6.2 at deep focus on Februaru 22, 2013.

Despite its rarity, forecast 115295 had expected this quake within about 50 km of this epicenter was likely around March 19.

 

O: 25MAR2018 14:28:34  26.8S   63.4W Mw=5.6  EMSC   SANTIAGO DEL ESTERO, ARGENTINA

P: 19MAR2018 115295    27.0S   63.0W 4.0-5.6 CAAAA  Argentina                  

 

An M 2.4 in eastern Kentucky was the most unusual quake in the U.S. or Canada today. It was not reported felt but was probably felt lightly in the epicentral area. The last earthquake of M>=2.4 in eastern Kentucky within about 50 km of this epicenter was an M 2.8 on December 17, 2017 and prior to that an M 2.5 on February 24, 2016. The largest quake in the area in the past 28 years was an M 3.6 on February 19, 1995. Forecast 115425 had expected this event south of today's epicenter likely around March 26.

 

O: 25MAR2018 09:26:49  38.7N   83.4W MD=2.4  EMSC   EASTERN KENTUCKY             

P: 26MAR2018 115425    37.0N   83.0W 2.0-4.2 ABAAA  Kentucky/Tennessee/NC      

 

 

GLOBAL SEISMIC ACTIVATION BEGINS WITH STRONG QUAKES

 

EARTHQUAKE SUMMARY FOR MARCH 24, 2018

 

A series of strong and unusual earthquakes began the expected global seismic activation today. These were, for the most part, located within about 10-15 degrees of the geomagnetic equator and were probably promoted by geomagnetic effects from  the last and current geomagnetic storms. These earthquakes which included an M 5.2 in Ethiopia and events of M 6.2-6.3 in New Ireland and the South Indian Ocean are the first of M>=6 in the world since an aftershock of M 6.7 in New Britain on March 8, 2018 and an M 6.7 two days before in PNG. The last earthquake in the world which was not a PNG aftershock of M>=6 occurred on February 27 with M 6.1 in the Macquarie Island region. The last mainshock of M>=6.2 in the world was the PNG mainshock of M 7.5-7.6 on February 25, 2018, a month ago. Global seismicity is often high at the end of March and the beginning of April as weather patterns are active and change. Previous issues of this summary had expected this global seismic activation at this time as:

 

 

"Global seismicity, especially at about 10-15 degrees from the geomagnetic equator and at auroral high latitudes is expected to be high during the period March 23-27 due to this storm. A major earthquake still appears likely towards the end of March." (March 23, 2018)

 

Further activity associated with PNG and Alaska would most likely occur near 103 and 144 degrees from those events. Among other areas at this distance from PNG include southern and Baja California north to Mammoth Lakes, Utah, Idaho,  as well as eastern Turkey, the middle east, including Ethiopia and the east Africa rift valley in Tanzania and south to Malawi. At 144 degrees from PNG include areas of Colombia and the northern Caribbean." (March 23-24, 2018)

 

Of particular note in today's seismicity was an M 5.2 in Ethiopia, an area singled out in the previous issue. This earthquake occurred at the maximum of a geomagnetic storm which reached high latitude KP 6 about the same time as this event, and a follow-up event in the northern Mindanao region of M 5.1 occurred (about 1030 UT). This region of Ethiopia has been quiet at this  magnitude level for nearly seven years - the last such event within about  200 km was an M 5.7 and 5.6 on June 12, 2011. Prior to that the last such event also occurred six years before with a swarm of M 5.2-5.6 events on September 20-26, 2005. Today's earthquake was not reported felt in this epicentral area but was probably felt locally. Earthquakes in Ethiopia often occur with strong solar flares and/or geomagnetic storms. The event in Ethiopia was also  at 103 degrees from the epicenter of the PNG quakes, a distance which has seen considerable activity following the mainshock in PNG on February 25. This activity, including moderate events in Tanzania, Malawi has been  unusual enough to warrant several previous notations in this summary.

 

Forecast 115371 had expected today's event in Ethiopia was likely within about

100 km of this epicenter around March 22.

 

O: 24MAR2018 10:27:31  13.4N   39.9E mb=5.2  EMSC   ETHIOPIA                     

O: 24MAR2018 10:27:32  13.5N   39.9E mb=5.2  ANSS   E of Mek'ele Ethiopia

P: 22MAR2018 115371    13.0N   41.0E 3.5-5.1 AAAAA  Ethiopia                   

 

A moderate M 4.6 also occurred in Tanzania today near local solar midnight and also may have been promoted by geomagnetic and tidal effects. NEIC reported this earthquake of M 4.6 in Tanzania was felt with intensity II-III in the area(s) of Tanzania at Kahama, Kasamwa, Mwanza and in Kigali, Rwanda. The last earthquake to occur in the Lake Victoria region of Tanzania with M>=4.6 occurred on May 29, 2002 more than 15 years ago. This is not an aftershock of the M 4.7 and 4.5 of March 3 and 5, 2018 which occurred about 500 km to the southeast of today's epicenter but represents another active epicenter. Forecast 115074 expected today's event was likely to the northwest around March 21.

 

O: 24MAR2018 21:18:37   3.4S   32.4E mb=4.6  EMSC   LAKE VICTORIA REGION, TANZANIA

P: 21MAR2018 115074     2.0S   29.0E 3.0-4.6 BBCAA  Lake Victoria area         

 

An earthquake in northern Mindanao, Philippines, on the geomagnetic equator along with Ethiopia occurred minutes after the event in Ethiopia. It too, was likely promoted by the geomagnetic storm.  PHIVOLCS reported this earthquake of M 5.1-5.2 was felt with intensity IV in Burgos and Santa Monica, Surigao Del Norte; III in Pilar and Del Carmen, Surigao del Norte; II in Surigao City; General Luna and Dapa, Surigao del Norte and I in Socorro, Surigao del Norte, Philippines. NEIC reported this earthquake of M 5.1 in Northern Mindanao, Philippines was felt with intensity IV in Dapa, Caraga, Philippines and II-III in the area(s) of Brasilisa, Philippines. The last earthquake within about 100 km of this epicenter in the Caraga region of the Philippines occurred December 17, 2017 with M 5.1. The last of M>=5.2 occurred nearly a year ago on April 23, 2017 with M 5.3. Forecast 115060 had expected a moderate quake in this area around March 19.

 

O: 24MAR2018 10:34:37  10.2N  126.0E mb=5.1  EMSC   PHILIPPINE ISLANDS REGION    

O: 24MAR2018 10:34:37  10.1N  126.0E mb=5.1  ANSS   Santa Monica Philippines

O: 24MAR2018 10:34:32  10.1N  126.2E MS=5.2  PHI  Felt with intensity IV

P: 19MAR2018 115060     9.0N  126.0E 4.0-5.4 BBAAA  Central Philippines        

 

The other large earthquake in the world today was an M 6.3 in the region of New Britain east of Papua New Guinea.  NEIC reported this earthquake of M 6.3 in New Britain was felt with intensity IV in the area(s) of Kimbe, New Britain. The last earthquake within about 200 km of this epicenter in New Britain with M>=6.3 occurred on May 5, 2015 as an M 7.5. Today's event may be an aftershock of that as they occurred within about 50 km of each other. Earthquakes of M 6.3 have since hit the area slightly more than 200 km from today's epicenter on March 5, 2017 (M 6.3) and October 15, 2016 (M 6.4). Forecast 115351 expected this event was likely around March 22.

 

O: 24MAR2018 13:20:56   5.6S  151.4E mb=4.6  EMSC   NEW BRITAIN REGION, P.N.G.   

O: 24MAR2018 11:23:32   5.5S  151.5E mw=6.3  ANSS   Kimbe Papua New Guinea

O: 24MAR2018 11:23:35   5.6S  151.5E Mw=6.3  EMSC   NEW BRITAIN REGION, P.N.G.   

P: 22MAR2018 115351     5.0S  150.0E 4.0-5.5 AABAA  New Ireland                

 

 

 

In addition to the M 5.2 in Ethiopia other events today at 103 degrees from PNG included the nominal activity in southern California and an M 4.6 in Tanzania, an M 2.2 in northern Idaho and the largest in a recent series in eastern Turkey of M 4.3. The last event in eastern Turkey with M>=4.2 occurred March 7, 2018 with M 4.2 and prior to that as an M 5.1 nearly a year ago on May 11, 2017.

 

O: 24MAR2018 15:04:06  38.3N   41.0E mb=4.3  EMSC   EASTERN TURKEY                

P: 24MAR2018 115452    38.0N   43.0E 3.5-4.9 AABAA  Turkey                     

 

An earthquake in the South Indian Ocean of M 6.2-6.3 was also well forecast to occur at this time. This is a remote area and this event was not reported felt. It occurred near local solar midnight and tidal stresses may have helped promote this event as did geomagnetic effects at this high latitude. The last earthquake within about 200 km of this epicenter with M>=6.3 was an M 6.5 on November 10, 2010. Other quakes hit the region with M 6.3-6.5 on October 29, 2005 and February 18, 1994. The antipode of this event is in southern Ontario, Canada near Ohio at 45N 84W. A light sympathetic quake could occur near this epicenter in the next several days.  Forecast 115569 had expected this event within about 25 km of this epicenter was likely around March 26 as a moderately large earthquake.

 

O: 24MAR2018 19:58:38  45.8S   96.1E Mw=6.2  EMSC   SOUTHEAST INDIAN RIDGE       

O: 24MAR2018 19:58:33  45.8S   96.1E mw=6.3  ANSS   Southeast Indian Ridge"

P: 26MAR2018 115569    46.0S   96.0E 4.0-5.6 AAAAA  So. Indian Ocean           

 

O: 24MAR2018 13:18:09  46.3N  115.0W ML=2.2  EMSC   NORTHERN IDAHO               

P: 24MAR2018 115469    44.5N  114.6W 2.0-3.9 ABAAA  Montana/Idaho               

 

The strongest seismicity in the U.S. or Canada today continued as a swarm in the Kodiak Island area of Alaska. The largest of these today was an M 4.5. This summary noted this swarm in the previous issue as:

 

"The strongest earthquakes in the U.S. or Canada today occurred in a swarm in the Kodiak Island region of Alaska. This  about 200 km west of the aftershock activity in the Gulf of Alaska following the M 6.0 there on January 23.  These included events of M 4.8, 4.5 and 3.8. The M 4.8 was the strongest within about 200 km of this epicenter since an M 5.2 on May 11, 2017 and prior to that an M 5.2 on September 18, 2012.  Forecast 115495 had expected regional activity with magnitude up to M 5.0 around March 23. Like the activity off the northern coast of California of M 4.5 and 4.7 yesterday, this activity in the Kodiak region may have been promoted by motions of the North American plate associated with nor'easter Toby." (March 23-24, 2018)

 

O: 24MAR2018 06:39:38  56.1N  153.2W ML=3.1  EMSC   KODIAK ISLAND REGION, ALASKA

O: 24MAR2018 06:04:32  56.1N  153.2W mb=3.9  EMSC   KODIAK ISLAND REGION, ALASKA

O: 24MAR2018 06:42:34  56.1N  153.4W ML=3.2  EMSC   KODIAK ISLAND REGION, ALASKA

O: 24MAR2018 06:00:05  56.2N  153.4W mb=4.5  EMSC   KODIAK ISLAND REGION, ALASKA

O: 24MAR2018 06:08:33  56.0N  153.3W ML=3.2  EMSC   SOUTH OF ALASKA              

P: 23MAR2018 115495    55.0N  150.0W 3.5-5.0 AABAA  Gulf of Alaska             

 

KODIAK ISLAND, ALASKA SWARM UNUSUAL

 

EARTHQUAKE SUMMARY FOR MARCH 23, 2018

 

The strongest seismicity of the day today occurred in the Fiji Islands with M 5.1 and M 5.2. These are not uncommon events in the region and were not reported felt. Earthquakes in the Fiji Islands during 2018 have included an M 6.0 on February 1; an M 5.9 on February 9 and January 16 and most recently an M 5.7 on March 9, 2018. Forecasts 115534 and 115292 had expected this activity in mid- to late- March.

 

O: 23MAR2018 17:32:29  15.8S  177.5W mb=5.1  EMSC   FIJI REGION                  

P: 26MAR2018 115534    15.0S  176.0W 4.0-5.4 BABAA  Samoa Islands              

 

O: 23MAR2018 19:08:02  17.8S  178.6W mb=5.2  EMSC   FIJI REGION                  

P: 18MAR2018 115292    19.0S  178.0W 4.0-5.5 BBAAA  Tonga Islands              

 

The strongest earthquakes in the U.S. or Canada today occurred in a swarm in the Kodiak Island region of Alaska. This  about 200 km west of the aftershock activity in the Gulf of Alaska following the M 6.0 there on January 23.  These included events of M 4.8, 4.5 and 3.8. The M 4.8 was the strongest within about 200 km of this epicenter since an M 5.2 on May 11, 2017 and prior to that an M 5.2 on September 18, 2012.  Forecast 115495 had expected regional activity with magnitude up to M 5.0 around March 23. Like the activity off the northern coast of California of M 4.5 and 4.7 yesterday, this activity in the Kodiak region may have been promoted by motions of the North American plate associated with nor'easter Toby.

 

O: 24MAR2018 06:04:32  56.1N  153.2W Ml=3.8  EMSC   KODIAK ISLAND REGION, ALASKA 

O: 24MAR2018 06:00:06  56.2N  153.4W mb=4.5  EMSC   KODIAK ISLAND REGION, ALASKA 

O: 24MAR2018 05:52:41  56.3N  153.3W mb=4.8  EMSC   KODIAK ISLAND REGION, ALASKA 

P: 23MAR2018 115495    55.0N  150.0W 3.5-5.0 ABBAA  Gulf of Alaska             

 

The largest earthquake in California today was an M 3.1 north of Los Angeles on the San Andreas Fault zone.  NEIC reported this earthquake of M 3.1 in Southern California was felt with intensity II-III in the area(s) of Ontario and Escalon, California.  This is a somewhat unusual event, the first of M>=3.1 in the area within about 40 km of this epicenter since an M 3.6 on June 4, 2017 and prior to that on January 14, 2016 with M 3.6 and 3.3.  Forecast 115184 expected an event about 40 km to the northwest of this was likely around March 19. This event is at 102 degrees from PNG and may have been promoted by energy from that location.

 

O: 23MAR2018 08:49:25  35.4N  117.8W ML=3.1  EMSC   SOUTHERN CALIFORNIA          

P: 19MAR2018 115184    35.7N  118.1W 2.5-4.6 BAAAA  So. California             

 

Seismicity is expected to increase beginning today due to geomagnetic stresses and effects from the PNG earthquake of M 7.6 of February 25 and the M 8.0 in the Gulf of Alaska of January 23. As reported in earlier issues of this summary such effects would be:

 

"Global seismicity, especially at about 10-15 degrees from the geomagnetic equator and at auroral high latitudes is expected to be high during the period March 23-27 due to this storm. A major earthquake still appears likely towards the end of March." (March 23, 2018)

 

Further activity associated with PNG and Alaska would most likely occur near 103 and 144 degrees from those events. Among other areas at this distance from PNG include southern and Baja California north to Mammoth Lakes, Utah, Idaho, as well as eastern Turkey, the middle east, including Ethiopia and the east Africa rift valley in Tanzania and south to Malawi. At 144 degrees from PNG include areas of Colombia and the northern Caribbean. Areas at 144 degrees from Alaska include the South Indian Ocean, among others while some areas of the mid-east are near 103 degrees from Alaska.

 

ACTIVE CALIFORNIA AFTER MODERATE QUAKES OFF NORTH SHORE

 

EARTHQUAKE SUMMARY FOR MARCH 22, 2018

 

The largest quakes in the U.S. or Canada today were a pair of moderate earthquakes of M 4.5 and 4.7 off the coast of northern California.

These were followed and preceded by a series of light earthquakes throughout California, apparently breaking the quiet period which has persisted for several weeks. The earthquakes off northern California followed a series of minor events in the region, apparently foreshocks which have been linked in the previous issue of this summary to nor'easter Toby. More than 1200 people reported to NEIC that they had felt this earthquake. These included intensity VI in Petrolia; V in Rio Dell; IV in Ferndale and Loleta, Hydesville, Eureka, Carlotta, Bayside, Whitethorn, McKinleyville, California. Lesser shaking was reported from Scotia, Fortuna, Arcata, Bayside, and in general within about 200 km of the epicenter. Similar shaking was associated with the M 4.6 earlier in the day. Aftershocks were also reported felt with light to moderate intensity. As noted in the previous issue of this summary this activity was probably promoted by motions of the North American plate induced from nor'easter Toby which hit the northeastern U.S. over the past two days and was noted here as:

 

"Effects on seismicity (of Toby) in the western U.S. and Canada associated with plate motions induced by the geomagnetic storm and Toby are likely to maximize in the next  two days and may include a regional moderate earthquake." (March 20-22, 2018)

 

The earthquake of M 4.7 is the largest in the area within about 100 km of this epicenter since an M 5.1 on July 29, 2017 and prior to that on July 3, 2016 with M 5.7. The last such event east of 125 West longitude was an M 5.7 three years ago on January 28, 2015. No damage was associated with today's earthquakes.   Forecast 115477 had expected this series to maximize within about 50 km of these epicenters around March 23.

 

O: 23MAR2018 03:52:53  40.4N  124.4W MD=2.2  EMSC   OFFSHORE NORTHERN CALIFORNIA 

O: 23MAR2018 03:18:50  40.4N  124.4W MD=3.0  EMSC   OFFSHORE NORTHERN CALIFORNIA 

O: 23MAR2018 03:09:39  40.5N  124.5W Mw=4.7  EMSC   OFFSHORE NORTHERN CALIFORNIA 

O: 22MAR2018 16:24:49  40.8N  124.3W Mw=4.5  EMSC   OFFSHORE NORTHERN CALIFORNIA 

P: 23MAR2018 115477    40.2N  124.2W 2.5-4.5 AAAAA  Off Coast of No. Calif     

 

An earthquake of M 5.2 hit in the northern mid-Atlantic Ocean today. This was the strongest earthquake located on the earth today. The previous issue of this summary had noted the possibility of a moderate earthquake in this area which is antipodal to TC Nora as follows:

 

"TC Nora formed today south of Papua New Guinea and north of Australia with winds up to 50 kts. It is expected to stay in this general area for several more days before turning south into Australia. New Guinea to the north is a seismic region where strong aftershocks of the February 25 event could be promoted by stresses from TC Nora. The antipode is at 10N 44W in the central mid-Atlantic region where a moderate earthquake could be promoted from antipodal focusing from Nora." (March 21-22, 2018)

 

The last earthquake within about 200 km of today's epicenter in the mid-Atlantic

Ridge with M>=5.2 was an M 5.7 on October 20, 2016 and prior to that an M 6.6 on June 24, 2013 about 250 km to the southeast. Forecast 115380 had expected today's event was likely north of this epicenter around March 25.

 

O: 23MAR2018 07:40:31  12.6N   44.6W mb=5.2  EMSC   NORTHERN MID-ATLANTIC RIDGE  

P: 25MAR2018 115380    15.0N   46.0W 4.0-5.5 ACBAA  Mid-Atlantic Ridge         

 

 

PNG, TIDES, GEOMAGNETIC STORM, NOR'EASTER PROMOTE SEISMICITY

 

EARTHQUAKE SUMMARY FOR MARCH 21, 2018

 

The strongest seismicity in the world today occurred near the geomagnetic equator. Although no strong earthquakes occurred, several events of moderate magnitude in Indonesia suggested promotion from the recent geomagnetic storm as suggested in previous issues of this report:

 

 

"The geomagnetic field saw quiet conditions today.  The AP level was 8. High latitude geomagnetic field also saw quiet conditions with AP at 4. This appears to conclude the strongest geomagnetic storm since December 5, 2017.  Global seismicity, especially at about 10-15 degrees from the geomagnetic equator and at auroral high latitudes is expected to be high during the period March 22-26 due to this storm. A major earthquake appears likely towards the end of March." (March 20-21, 2018)

 

Forecast 115086 had expected this event in mid-March within about 50 km of this epicenter. BMG reported the M 5.3-5.4 was felt with intensity III-IV in Kepahiang, Seluma and Liwa, Benkulu, Indonesia. This event is at 103 degrees from the great M  8.0 in Alaska of January 23 and was probably promoted from that source.

 

O: 22MAR2018 06:40:48   4.0S  103.7E mb=4.5  EMSC   SOUTHERN SUMATRA, INDONESIA  

O: 22MAR2018 00:08:03   4.6S  102.8E mb=5.3  EMSC   SOUTHERN SUMATRA, INDONESIA  

O: 22MAR2018 00:08:02  04.7N  102.8E MS=5.4  BMG  Felt with intensity III-IV

P: 16MAR2018 115086     5.0S  103.0E 4.0-5.4 CAAAA  So. of Sumatera            

 

A series of events in Halmahera included an M 5.2 today. This and the activity in Southern Sumatra is 10-15 degrees south of the local geomagnetic equator and may have been promoted by geomagnetic effects. Forecast 115336 had expected this activity in Halmahera around March 24.

 

 

NEIC reported this earthquake of M 5.2 in Maluku, Indonesia was felt with intensity IV in the area(s) of Ternate, Maluku Utara, Indonesia.  BMG reported the M 4.9-5.2 was felt with intensity II-III in Ternate, and III in Tobelo, Halmahera, Indonesia. BMG reported the M 4.5-4.6 was felt with intensity II-III in Tobelo, Halmahera, Indonesia. The M 5.2 occurred within 10 minutes of local solar midnight and may have been promoted by tidal stresses which maximize at this hour.

 

O: 21MAR2018 15:33:47   1.5N  127.9E Mw=5.2  EMSC   HALMAHERA, INDONESIA         

O: 21MAR2018 15:33:17  01.9N  127.8E MS=4.9  BMG  Felt with intensity II-III

O: 21MAR2018 16:22:26  01.6N  127.8E MS=4.5  BMG  Felt with intensity II-III

O: 21MAR2018 16:22:25   1.6N  127.9E mb=4.6  EMSC   HALMAHERA, INDONESIA         

O: 21MAR2018 15:33:14   2.1N  127.8E mb=4.6  EMSC   MOLUCCA SEA                  

P: 24MAR2018 115336     1.0N  127.0E 4.0-5.6 BAAAA  Halmahera                  

 

 

The strongest earthquake of the day was an M 5.4 in the Kermadec Islands, New Zealand about 15 degrees south of the geomagnetic equator. This is probably an  aftershock of an M 5.9 at this same epicenter of January 17, 2018. An earthquake of M 6.2 also hit about 100 km west of this on December 8, 2017. None of these events were felt in this remote area. Forecast 115313 had expected this activity within about 50 km around March 20. This epicenter is at the fourth node (90 degrees) from Alaska and was probably promoted from that source. Activity in Iran today including an M 5.0 is also at the fourth node from PNG.

 

O: 22MAR2018 07:26:24  30.3S  177.6W mb=5.4  EMSC   KERMADEC ISLANDS, NEW ZEALAND

P: 20MAR2018 115313    30.0S  177.0W 4.0-5.4 AAAAA  No. Kermadec Islands       

 

Seismicity which may have been promoted from nor'easter Toby also continued today. A series of light aftershocks followed in the Malone, New York region following yesterday's M 2.7-3.4. These included an M 2.7 lightly felt in the aftershock area.

 

"A light earthquake of M 2.7 (Earthquakes Canada gives M 3.4 to this event) shook northern New York State today as the fourth nor'easter of the month (Toby) swept through the region to the south. It is likely that stresses from this storm helped promote the occurrence of this quake at this time. NEIC reported it was felt with intensity IV in Dickinson Center, New York and II-III in

North Lawrence, Brushton, Moira, North Bangor, Brasher Falls, Winthrop, West Stockholm, Saint Regis Falls, Potsdam, Massena, Norfolk, Norwood, Potsdam, South Colton, Burke, Madrid, Canton, Colton, and Lisbon, New York and in Canada in Montreal, Quebec, and in Constance Bay, Ontario. Effects on seismicity in the western U.S. and Canada associated with plate motions induced by the geomagnetic storm and Toby are likely to maximize in the next  two days and may include a regional moderate earthquake. The last earthquake with M>=2.7 within about 50 km of this epicenter in New York State was an M 3.3 on November 28, 2015 and prior to that as an M 3.0 on August 24, 2011, the only such events in the area in the past 10 years.  Forecast 115219 had expected this activity was likely around March 20." (March 20-21, 2018

 

The mainshock of M 3.4 occurred at nearly exactly local solar midnight with a regional M 1.7 also near midnight a day later. This suggests that tidal stresses, which maximize at this hour, promoted this seismicity. The last  event of M>=3.4 in the area within about 50 km of this epicenter occurred on April 8, 2003 with M 3.7.

 

O: 21MAR2018 04:59:12  44.8N   74.6W ML=3.4  NRCA  33 km S from Cornwall

O: 21MAR2018 22:51:58  44.9N   74.7W ML=2.7  NRCA  18 km S from Cornwall

O: 21MAR2018 22:51:58  44.9N   74.7W ml=1.9  ANSS   Massena New York             

P: 20MAR2018 115219    45.0N   75.0W 2.0-4.5 AAAAA  New York State             

 

O: 22MAR2018 04:35:40  45.8N   75.3W ML=1.7  NRCA  17 km NW from Saint-Andre-Avell

P: 20MAR2018 115219    45.0N   75.0W 2.0-4.5 AAAAA  New York State             

 

On the northwest coast of the U.S. a series of light earthquakes continued near the coast of northern California. These may have been promoted by nor'easter Toby as noted in previous issues of this report:

 

"Effects on seismicity in the western U.S. and Canada associated with plate motions induced by the geomagnetic storm and Toby are likely to maximize in the next two days and may include a regional moderate earthquake." (March 20-21, 2018)

 

This area has been active in recent days and tends to have a moderate event following each of the nor'easters this month. The last event of M>=2.6 within  about 50 km of these epicenter occurred on March 14 with M 2.9 and March 9, 2018 with M 4.5 as noted in this summary at the time:

 

"an M 4.5 off the coast of Northern California may have been promoted by motions of North America associated with landfall of a powerful nor'easter which hit the eastern seaboard of North America over the past two days This summary had expected such a reaction in previous issues as:  

 

"This may be a reaction to the nor'easter which hit the area several days ago. A very strong nor'easter is again expected around March 7-8 and could promote regional seismicity in the northeastern North American plate as well as moderate activity on the western boundaries of the North American plate." (March 6-7, 2018)

 

Moderate seismicity is still considered likely from areas off northern California to southern Alaska as promoted by the nor'easter." (March 8-9, 2018)

 

NEIC reported this earthquake of M 2.6 off northern California  was felt with intensity II-III in the area(s) of Arcata, California.  An M 2.7 south of this was reported felt with intensity II in Ferndale and Eureka, California later in the day. Light earthquakes in this area are common but these may have been promoted by stresses from nor'easter Toby which hit the northeast U.S. today and had been expected to promoted this type of seismicity in previous issues of this summary as:

 

Forecast 115477 had expected this activity would reach a peak around March 23.

 

O: 22MAR2018 03:57:35  40.3N  124.5W MD=2.5  EMSC   OFFSHORE NORTHERN CALIFORNIA 

O: 21MAR2018 13:50:39  40.8N  124.6W MD=2.6  EMSC   OFFSHORE NORTHERN CALIFORNIA 

P: 23MAR2018 115477    40.2N  124.2W 2.5-4.5 AAAAA  Off Coast of No. Calif     

 

A series of light earthquakes also occurred in Utah today with maximum up to M 3.0.  NEIC reported this earthquake of M 3.1 in Utah was felt with intensity II-III in the area(s) of Loa, Torrey and Teasdale, Utah.  They lie at 105 degrees from Papua New Guinea (PNG) and may have been promoted from that source. An earthquake of M 3.7 hit the region on February 16, 2018 and again with M 3.6 on February 28 but these were about 75 km to the west and south of today's swarm any probably were not related. Forecast 115195 had expected this activity was likely around February 20.

 

O: 22MAR2018 03:30:05  38.4N  111.7W ML=2.0  EMSC   UTAH                         

O: 22MAR2018 05:00:10  38.4N  111.7W ML=2.2  EMSC   UTAH                         

O: 22MAR2018 00:27:44  38.4N  111.7W ML=3.0  EMSC   UTAH                         

P: 20MAR2018 115195    38.6N  112.7W 2.0-4.1 AAAAA  Utah area                  

 

 

LIGHT QUAKE HITS NEW YORK AS NOR'EASTER TOBY ARRIVES

 

EARTHQUAKE SUMMARY FOR MARCH 20, 2018

 

A light earthquake of M 2.7 shook northern New York State today as the fourth nor'easter of the month (Toby) swept through the region to the south. It is likely that stresses from this storm helped promote the occurrence of this quake at this time. NEIC reported it was felt with intensity IV in Dickinson Center, New York and II-III in North Lawrence, Brushton, Moira, North Bangor, Brasher Falls, Winthrop, West Stockholm, Saint Regis Falls, Potsdam, Massena, Norfolk, Norwood, Potsdam, South Colton, Burke, Madrid, Canton, Colton, and Lisbon, New York and in Canada in Montreal, Quebec, and in Constance Bay, Ontario. Effects on seismicity in the western U.S. and Canada associated with plate motions induced by the geomagnetic storm and Toby are likely to maximize in the next  two days and may include a regional moderate earthquake. The last earthquake with M>=2.7 within about 50 km of this epicenter in New York State was an M 3.3 on November 28, 2015 and prior to that as an M 3.0 on August 24, 2011, the only such events in the area in the past 10 years.  Forecast 115219 had expected this activity was likely around March 20.

 

 

O: 21MAR2018 04:59:13  44.8N   74.6W ML=2.7  EMSC   NEW YORK                     

P: 20MAR2018 115219    45.0N   75.0W 2.0-4.5 AAAAA  New York State             

 

The strongest earthquake in the world today was an M 5.2 in the area of Guerrero, Mexico. This followed a foreshock of M 4.9 about an hour earlier.  NEIC reported this earthquake of M 5.2 in Guerrero, Mexico was felt with intensity II-III in the area(s) of Puebla, Ixtapaluca, Mexico City, Coatepec, Naucalpan, Tlalnepantla, and Lopez Mateos, Mexico. NEIC reported this earthquake of M 4.9 in Oaxaca was felt with intensity II-III in the area(s) of Mexico City and Lopez Mateos, Mexico. This activity is part of the aftershock sequence of the M 7.2 of February 16, 2018 and is the strongest within about 50 km of today's epicenter since an M 5.8 on August 13, 2014. Forecasts 115114 and 115385 had expected this activity between March 17 and 24.

 

O: 20MAR2018 16:29:59  15.9N   98.7W ML=4.1  EMSC   OFFSHORE GUERRERO, MEXICO    

O: 20MAR2018 16:44:02  16.4N   98.4W mb=4.9  EMSC   GUERRERO, MEXICO              

O: 20MAR2018 17:46:58  16.5N   98.4W Mw=5.2  EMSC   GUERRERO, MEXICO             

O: 20MAR2018 18:18:48  16.0N   98.7W ML=4.0  UNAM  l SUROESTE de PINOTEPA NACIONAL, O

O: 20MAR2018 16:29:59  15.9N   98.7W ML=4.1  UNAM  l SUROESTE de PINOTEPA NACIONAL, O

O: 20MAR2018 18:12:03  15.9N   98.7W ML=4.2  UNAM  l SUROESTE de PINOTEPA NACIONAL, O

O: 20MAR2018 18:07:17  16.0N   98.7W ML=4.6  UNAM  l SUROESTE de PINOTEPA NACIONAL, O

O: 20MAR2018 18:07:25  16.5N   98.4W mb=4.3  EMSC   GUERRERO, MEXICO              

P: 17MAR2018 115114    17.0N   98.0W 3.5-5.3 BAAAA  Oaxaca, Mexico             

P: 24MAR2018 115385    17.0N   98.0W 3.5-5.3 BAAAA  Oaxaca, Mexico             

 

Other portions of  Mexico also remained active today. In addition to the two moderate events of M>=4.9 in the Guerrero region, the area of northern Baja saw continuing moderate events associated with the swarm there which began yesterday. This activity is at 103-104 degrees from the M 7.6 epicenter in Papua New Guinea (PNG) and was likely promoted by concentrated energy from that source. A second site northwest of this near Imperial and Brawley, California was also active today with a series of events including five of M>=2. This is another area likely promoted from PNG. Forecast 115175 had expected this activity around March 19.

 

O: 20MAR2018 13:10:41  30.8N  114.3W ML=3.7  EMSC   GULF OF CALIFORNIA           

O: 19MAR2018 23:18:24  31.0N  114.1W ML=3.4  UNAM  l ESTE de SAN FELIPE, BC *: 31.08°

O: 20MAR2018 05:20:53  30.9N  114.1W ML=3.6  UNAM  l ESTE de SAN FELIPE, BC *: 30.92°

O: 19MAR2018 23:15:55  30.9N  114.1W ML=3.8  UNAM  l ESTE de SAN FELIPE, BC *: 30.98°

O: 20MAR2018 13:12:13  31.0N  114.1W ML=3.8  UNAM  l ESTE de SAN FELIPE, BC *: 31.02°

O: 19MAR2018 23:12:10  30.9N  114.2W ML=3.4  UNAM  l ESTE de SAN FELIPE, BC *: 30.95°

O: 20MAR2018 11:25:49  31.0N  114.2W ML=3.4  UNAM  l ESTE de SAN FELIPE, BC *: 31.03°

O: 20MAR2018 03:48:14  31.0N  114.2W ML=3.4  UNAM  l ESTE de SAN FELIPE, BC *: 31.08°

O: 20MAR2018 09:21:29  31.0N  114.2W ML=3.6  UNAM  l ESTE de SAN FELIPE, BC *: 31.03°

O: 20MAR2018 05:01:16  31.1N  114.2W ML=3.6  UNAM  l ESTE de SAN FELIPE, BC *: 31.15°

O: 19MAR2018 23:40:26  30.9N  114.2W ML=3.7  UNAM  l ESTE de SAN FELIPE, BC *: 30.98°

O: 20MAR2018 01:41:46  31.0N  114.2W ML=3.7  UNAM  l ESTE de SAN FELIPE, BC *: 31.0°,

O: 20MAR2018 15:01:32  31.0N  114.2W ML=3.7  UNAM  l ESTE de SAN FELIPE, BC *: 31.0°,

O: 20MAR2018 13:10:41  30.7N  114.2W ML=3.7  UNAM  l SURESTE de SAN FELIPE, BC *: 30.

O: 20MAR2018 09:16:09  30.9N  114.2W ML=3.8  UNAM  l ESTE de SAN FELIPE, BC *: 30.97°

O: 19MAR2018 23:56:10  30.9N  114.2W ML=4.0  UNAM  l ESTE de SAN FELIPE, BC *: 30.95°

O: 19MAR2018 23:13:05  31.0N  114.2W ML=4.5  UNAM  l ESTE de SAN FELIPE, BC *: 31.0°,

O: 19MAR2018 23:36:41  30.9N  114.2W ML=4.8  UNAM  l ESTE de SAN FELIPE, BC *: 30.97°

O: 20MAR2018 05:57:16  31.2N  114.3W ML=3.4  UNAM  l NORESTE de SAN FELIPE, BC *: 31.

P: 29MAR2018 115394    28.0N  112.0W 3.5-5.1 CCBAA  Gulf of California         

 

O: 20MAR2018 13:12:13  31.0N  114.2W ML=3.8  EMSC   GULF OF CALIFORNIA           

P: 26MAR2018 115441    31.9N  116.3W 2.5-4.4 CABAA  So. California             

 

O: 21MAR2018 03:00:04  32.9N  115.5W ML=2.0  EMSC   SOUTHERN CALIFORNIA          

O: 20MAR2018 12:08:53  32.9N  115.5W ml=2.2  ANSS   S of Brawley CA

O: 20MAR2018 12:08:37  32.9N  115.5W ml=2.3  ANSS   NE of Imperial CA

O: 20MAR2018 12:08:29  32.9N  115.5W ml=2.4  ANSS   SSE of Brawley CA

O: 20MAR2018 12:08:29  32.9N  115.5W ML=2.4  EMSC   SOUTHERN CALIFORNIA          

P: 19MAR2018 115175    32.4N  115.8W 2.5-4.6 AAAAA  So. California             

 

Other activity today at 103-104 degrees from PNG continued in an active site in Eastern Turkey which has seen a number of minor earthquakes in the past  two weeks. Forecast 115452 had expected this activity could maximize around March 24.

 

O: 20MAR2018 23:43:15  38.9N   43.5E ML=2.8  EMSC   EASTERN TURKEY               

O: 20MAR2018 22:10:46  38.9N   43.5E ML=3.3  EMSC   EASTERN TURKEY               

P: 24MAR2018 115452    38.0N   43.0E 3.5-4.9 BAAAA  Turkey                     

 

MODERATE QUAKES HIT NORTHERN BAJA AT 103-104 DEGREES FROM PNG

 

EARTHQUAKE SUMMARY FOR MARCH 19, 2018

 

At least two moderate earthquakes of M 4.5-4.6 and 4.6-4.8 were recorded in northern Baja California today. These events were not reported felt in this remote area but occurred at 103-104 degrees from the M 7.6 in Papua New Guinea (PNG) of February 25, 2018. This had been expected in this summary at the time of the PNG quake as:

 

"the preponderence of evidence is that these mainshocks in New Guinea do trigger subsequent moderate to strong quakes near 103 degrees away in Southern California in the region of Los Angeles or to the east. Given the 22- to 23 year cyclicity of strong earthquakes in this area, due at this time,  this summary is placing this region under a moderate seismic watch for the next month with the most likely large quakes at the end of March. A seismic watch indicates conditions are right for the development of significantly increased regional seismicity including the possibility of a strong earthquake in the watch period. The watch period may be extended depending on regional activity. The most likely area would be east of Los Angeles in the general area north of of Landers, California. Another area which could see increased activity at this time is the Mammoth Lakes region of the California-Nevada border. This is located at 102-103 degrees from the PNG quake and is subject to this type of triggering." (February 25-26, 2018)

 

The last series of earthquakes in this area of the northern Baja California occurred on March 28, 2016 with events up to M 5.5 and prior to that on March 21-22, 2014 reaching magnitudes up to M 4.9 and 5.2. Forecast 115175 had expected activity in the Baja area was likely around March 19. One of the strongest swarms in this area occurred exactly 49 years ago on March 20-21, 1969 with maximum events reaching M 6.0 (see Seismic history in this issue).

 

O: 19MAR2018 23:13:05  31.0N  114.2W ML=4.5  EMSC   GULF OF CALIFORNIA           

O: 19MAR2018 23:13:05  31.0N  114.2W ML=4.5  UNAM  l ESTE de SAN FELIPE, BC *: 31.0°,

O: 19MAR2018 23:36:41  30.9N  114.2W ML=4.8  UNAM  l ESTE de SAN FELIPE, BC *: 30.97°

O: 19MAR2018 23:36:50  31.2N  114.0W ML=4.6  EMSC   GULF OF CALIFORNIA           

P: 19MAR2018 115175    32.4N  115.8W 2.5-4.6 ABBAA  So. California             

 

California has been seeing very quiet seismic conditions in the past week, but  this is likely to change with these earthquake in Baja California. It is not likely that this is the last of this swarm but may also promote a resurgence of seismicity in California and Nevada at 102-104 degrees from PNG in the next 10 days.

 

The strongest earthquake in the U.S. or Canada today were an M 4.8 in the Rat Islands and an M 4.2 in the Fox Islands, Aleutians. It was not reported felt in the area. The last earthquake within about 150 km of this epicenter with M>=4.2 was an M 5.1 on January 28, 2018 followed by an M 4.2 aftershock.  Forecast 115249 had expected today's event was likely in mid-March.

 

O: 20MAR2018 00:28:55  53.3N  168.0W mb=4.2  ANSS   NE of Nikolski Alaska        

P: 14MAR2018 115249    53.5N  167.3W 3.5-4.9 CAAAA  Fox Islands, Aleutians     

 

The event in the Rat Islands of M 4.8 followed a small foreshock seconds before. It was not felt in the epicentral area. The last event of larger size in the Rat Islands was an M 5.1 on March 2 and an M 5.2 on February 9, 2018. Forecast 115255 expected today's event was likely in mid-March.

 

O: 19MAR2018 12:20:49  52.1N  178.3E mb=4.7  EMSC   RAT ISLANDS, ALEUTIAN ISLANDS

O: 19MAR2018 12:20:51  52.0N  178.3E mb=4.8  ANSS   Little Sitkin Island Alaska

O: 19MAR2018 12:20:48  53.1N  178.2E ml=4.0  ANSS   Rat Islands, Alaska

P: 14MAR2018 115255    52.0N  176.0E 4.0-5.6 BABAA  Rat Islands                

 

MODERATE QUAKES HIT KURILS; JAPAN

 

EARTHQUAKE SUMMARY FOR MARCH 18, 2018

 

The strongest seismicity of the day occurred in the region from Tokyo, Japan (M 5.3) north to the southern Kuril Islands (M 5.6). The event near Tokyo occurred within minutes of local solar noon and was probably promoted by tidal stresses associated with the new moon which maximize at this hour.  NEIC reported this earthquake of M 5.0 east of Tokyo, Japan  was felt with intensity II-III in the area(s) of Chiba, Tokyo, Kanagawa, and Saitama Prefectures.  The last earthquake within about 100 km of this epicenter in Honshu with M>=5.3 occurred on January 9, 2018 and prior to that on February 19, 2017 both with M 5.3-5.4. The last of larger magnitude was an M 6.2 on September 23, 2016 after a series of events of M 5.3.  Forecast 115170 and 115437 had expected this activity within about 100 km of today's epicenter was likely between March 15 and 25.

 

O: 19MAR2018 02:45:10  35.2N  141.0E mb=5.3  EMSC   NEAR EAST COAST OF HONSHU, JAP

P: 15MAR2018 115170    36.0N  140.0E 4.0-5.4 BAAAA  Off East Coast Honshu      

P: 25MAR2018 115437    35.0N  141.0E 4.0-5.4 CAAAA  Off East Coast Honshu      

 

The M 5.6 in the Kuril Islands may have been promoted by the geomagnetic storm which reached KP 6 about the time of this earthquake. Geomagnetic changes often are associated with stronger events in the Kuril Islands. Today's event was not reported felt in this remote area which is capable of producing great earthquakes. The last earthquake within about 150 km of today's epicenter with M>=5.6 occurred on March 7, 2018 about 200 km east of today's epicenter with M 5.8 and prior to that on July 30, 2017 and November 14, 2014 both with M 5.7. Forecast 115234 had expected today's event within about 50 km of the epicenter was likely in mid-March. This epicenter is at 102 degrees from the M 7.6 north of Honduras of January 10, 2018 and probably was promoted by concentrated energy from that event. It is also at the seventh node (51-52 degrees) from the PNG quake of February 25 (M 7.6) and was probably promoted from that source as well.

 

 

O: 18MAR2018 18:00:12  45.4N  150.1E mb=5.6  EMSC   KURIL ISLANDS                

P: 15MAR2018 115234    45.0N  150.0E 3.5-5.4 BAAAA  So. Kurils                 

 

Another nor'easter may hit the northeast U.S. on March 21. Much of the stress along the northwestern North American plate has been relieved by previous nor'easters in the past two weeks and a strong induced earthquake in that region seems unlikely. The storm may take an unusual path, however, and will be watched by this summary for seismic connections.

 

A pair of moderate earthquakes of M 4.8 and 5.1 hit the Oaxaca, Mexico aftershock zone today. These were reported lightly felt in Oaxaca. Aftershocks of M>=5.1 have been uncommon in the region in recent months. The last was an M 5.4 on October 14, 2017. Forecast 115368 had expected today's activity was likely around March 22. This activity which centered around local solar midnight may have been promoted by tidal stresses associated with the new moon.

 

NEIC reported this earthquake of M 5.1 in Oaxaca, Mexico was felt with intensity IV in the area(s) of Salina Cruz, Oaxaca, Mexico.

 

O: 18MAR2018 23:26:42  15.9N   95.4W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO      

O: 19MAR2018 06:00:03  15.0N   94.3W ML=4.1  UNAM  al SUROESTE de TONALA, CHIS *: 15.

O: 18MAR2018 07:47:23  16.5N   94.7W ML=4.8  UNAM  l NORESTE de UNION HIDALGO, OAX *:

O: 19MAR2018 04:23:30  17.5N   94.8W ML=4.0  UNAM  l SURESTE de SAYULA DE ALEMAN, VER

O: 18MAR2018 09:22:02  16.3N   95.1W ML=5.1  UNAM  l NORESTE de S BLAS ATEMPA, OAX *:

O: 18MAR2018 08:43:09  16.0N   95.2W ML=4.2  UNAM  l SUR de SALINA CRUZ, OAX *: 16.0°

O: 18MAR2018 23:26:42  15.8N   95.4W ML=4.2  UNAM  l SUROESTE de SALINA CRUZ, OAX *:

O: 18MAR2018 08:43:09  16.0N   95.2W ML=4.2  EMSC   OFFSHORE OAXACA, MEXICO      

P: 22MAR2018 115368    16.0N   95.0W 3.5-5.1 BAAAA  Chiapas, Mexico            

 

 

The strongest earthquake in the U.S. or Canada today was an M 4.1 in the eastern Fox Islands, Aleutians of Alaska. This is an area which has not been active in recent months. The epicenter is to the south of most activity in  the area and may be an outer rise earthquake. Outer Rise events can help identify locations where stress in a downgoing slab are high and the possibility of a stronger earthquake exists. The last earthquake south of 51 N and between 170 and 172 degrees West longitude with M>=4.1 was an M 4.1 on January 23, 2010. Forecast 115244 had expected regional activity around March 18. 

 

O: 18MAR2018 12:51:30  50.9N  171.0W mb=4.1  ANSS   Amukta Island Alaska         

O: 18MAR2018 14:46:59  50.9N  171.1W mb=3.9  ANSS   Amukta Island Alaska         

P: 18MAR2018 115244    51.9N  176.0W 3.5-5.1 AACAA  Andreanoff Isls, Aleutians 

 

GEOMAGNETIC STORM LIKELY TO INCREASE EQUATORIAL SEISMICITY

 

EARTHQUAKE SUMMARY FOR MARCH 17, 2018

 

 

The geomagnetic field saw disturbed conditions today.  The AP level was 13. High latitude geomagnetic field also saw disturbed conditions with AP at 14. Maximizing AP at 20 with high latitude AP of 40, this is the strongest geomagnetic storm since December 17, 2017 when AP reached 24. High latitude kp reached 6 around 0900 and 1500 UT on March 16, the first such occurrence in more than a month. No major flares were associated with this geomagnetic storm. Global seismicity especially at about 10-15 degrees from the geomagnetic equator and at auroral high latitudes is expected to be high during the period March 20-24 due to this storm combined with the new moon stresses. A major earthquake appears likely towards the end of March.

 

The largest earthquake in the U.S. or Canada today occurred in the Unimak Island area with M 4.3-4.8. It was not reported felt in this remote area. The last earthquake within about 150 km of this epicenter with M>=4.8 occurred on June 30, 2017 with M 4.8. The only event with M>=5 in the area in the past 1.5 years was an M 5.1 on May 24, 2017. These are probably regional aftershocks of the M 5.8 north of today's epicenter which occurred October 27, 2016. An M 4.4 hit west of this on February 27, 2017. Forecast 115259 had expected today's earthquake was likely around March 17.

 

O: 17MAR2018 19:31:32  52.9N  163.1W mb=4.3  ANSS   False Pass Alaska            

O: 17MAR2018 19:31:41  53.8N  163.0W mb=4.8  EMSC   SOUTH OF ALASKA              

P: 17MAR2018 115259    54.6N  163.6W 3.5-5.0 ABAAA  Unimak Islands, Aleutians  

 

A moderate swarm of earthquakes occurred today in the Mammoth Lakes area on the California-Nevada border. Swarms such as this are not uncommon in this region but have not occurred since December 8, 2017. The last event of M>=3 in the region occurred two months ago on January 16, 2018 also in association with the new moon, as was today's swarm. The swarm was strongest near local solar noon and was probably promoted by tidal stresses associated with the new moon. This area is at 103 degrees from Papua New Guinea where a strong M 7.6 has been followed by an energetic aftershocks sequence since February 25. This summary has previously noted that earthquakes in Mammoth Lakes could be triggered from PNG at this time. Forecast 115144 had expected this activity around March 18.

 

O: 17MAR2018 17:13:55  37.7N  118.8W md=2.0  ANSS   Mammoth Lakes CA             

O: 17MAR2018 20:53:25  37.7N  118.8W md=2.0  ANSS   Mammoth Lakes CA             

O: 17MAR2018 18:24:24  37.7N  118.8W md=2.1  ANSS   Mammoth Lakes CA             

O: 17MAR2018 11:56:51  37.7N  118.8W md=2.2  ANSS   Mammoth Lakes CA             

O: 17MAR2018 19:19:33  37.7N  118.8W md=2.3  ANSS   Mammoth Lakes CA             

O: 17MAR2018 16:23:45  37.7N  118.8W md=2.4  ANSS   Mammoth Lakes CA             

O: 17MAR2018 11:31:55  37.7N  118.8W md=2.5  ANSS   Mammoth Lakes CA             

O: 17MAR2018 17:45:35  37.7N  118.8W md=2.9  ANSS   Mammoth Lakes CA             

O: 17MAR2018 16:23:22  37.7N  118.8W md=3.0  ANSS   Mammoth Lakes CA             

P: 18MAR2018 115144    37.8N  118.2W 2.5-4.6 AAAAA  California/Nevada area     

 

A swarm of earthquakes in Eastern Turkey also continued today with the maximum event of M 3.4. These were not reported felt in the epicentral area but continued the swarm of the past week in the area reaching moderate magnitudes. These epicenters, like those in Mammoth Lakes are at 102-103 degrees from PNG and were probably promoted by energy from that source. Forecast 115452 had expected this swarm was likely to reach maximum values around March 24.

 

O: 18MAR2018 06:29:22  38.7N   43.3E ML=2.6  EMSC   EASTERN TURKEY               

O: 18MAR2018 07:05:57  38.8N   43.5E ML=3.0  EMSC   EASTERN TURKEY               

O: 17MAR2018 21:21:04  38.8N   43.6E ML=3.4  EMSC   EASTERN TURKEY               

O: 18MAR2018 05:37:30  38.9N   43.5E ML=2.5  EMSC   EASTERN TURKEY               

P: 24MAR2018 115452    38.0N   43.0E 3.5-4.9 CAAAA  Turkey                     

 

O: 17MAR2018 06:19:56  39.4N   40.8E ML=2.8  EMSC   EASTERN TURKEY               

P: 18MAR2018 115194    39.0N   40.0E 3.5-5.1 AAAAA  Turkey                     

 

Another area which has been active since the PNG quake of February 25 is the region of Mozambique and Malawi in east Africa. Another earthquake of M 4.9  hit the region today. The series in this region began with an M 5.5 and M 5.2 on March 8, 2018. Like eastern Turkey and Mammoth Lakes, California, this  epicenter is at 103-104 degrees from PNG and was probably promoted from that source. Forecast 115009 had expected activity in the region around March 11. Stresses from TC Eliakim probably also help promote today's earthquake in  Malawi as noted in previous issues of this summary:

 

"Tropical Cyclone Eliakim continued today off Madagascar with winds up to 45 kts.   It is expected to track to the southeast reaching the antipodal area of Central California at 37N 122W around March 21-22 and perhaps helping to promote seismicity in that area." (March 17-18, 2018)

 

NEIC reported this earthquake of M 4.9 in Malawi was felt with intensity II-III in the area(s) of Malawi at Nsanje, Mulanje, Blantyre and Lilongwe.

 

O: 17MAR2018 15:12:23  16.8S   35.3E mb=4.9  EMSC   MOZAMBIQUE                   

O: 17MAR2018 15:12:22  16.8S   35.4E mb=4.9  ANSS   NE of Nsanje Malawi

P: 11MAR2018 115009    18.0S   42.0E 3.0-4.6 CBCAA  Madagascar area            

 

 

MODERATELY STRONG QUAKES IN SOUTH ATLANTIC; SOUTH SANDWICH ISLANDS

 

EARTHQUAKE SUMMARY FOR MARCH 16, 2018

 

The strongest earthquakes of the day were an M 5.8 on the Southern Mid-Atlantic Ridge and M 5.5 in the South Sandwich Islands. These events appear to confirm the tidal stress effect promoting earthquakes at this time. The tidal forecast as published in this report over the past two days had expected this pattern as:

 

 

"The new moon will arrive on March 17 at 13:12 UT. Longitudes at local solar noon at this time center on 17 West longitude and include areas of the Atlantic Ocean from Iceland, the Canary Islands and Ascension Island among other(s). These, including some areas off the coast of Spain and Portugal and the Strait of Gibraltar could see elevated seismicity in the next week, and some such the Ascension Island area have already seen moderately large earthquakes. Iceland is especially vulnerable to tidal effects at this time. In the east local solar midnight is centered at 163 East longitude and includes Vanuatu, New Zealand, the Solomon Is and eastern Papua New Guinea in the south and the Kamchatka-Komandorsky-Rat Islands to the north. These are the regions most likely to see tidal triggering in the next week, but global seismicity is likely to be high during this period outside these zones as well." (March 15, 2018)

 

The earthquake of M 5.8 in the Southern Mid-Atlantic Ridge was not felt and did not trigger a tsunami. The last earthquake within about 250 km of this epicenter in the Atlantic was an M 6.0 eighteen years ago on October 21, 2000, the only event of M>5.8 in the past 28 years at least. Two events of M 5.8 hit the area on January 17, 1997 and April 25, 1997. This epicenter is near the third node (120 degrees) from PNG and may have been promoted from that source.

 

O: 17MAR2018 05:50:16  47.5S   13.5W Mw=5.8  EMSC   SOUTHERN MID-ATLANTIC RIDGE  

 

The earthquake in the South Sandwich Islands of M 5.6 today was the strongest in that region since a similar M 5.5-5.6 about 200 km west of this on March 10, 2018 and prior to that on September 4, 2017 (M 6.0) and May 30, 2017 (M 5.7).   It was not reported felt in the epicentral area which is remote. Forecast 115326 had expected this event within about 150 km of the epicenter in the South Sandwich Islands.

 

O: 16MAR2018 09:25:03  56.4S   25.6W Mw=5.5  EMSC   SOUTH SANDWICH ISLANDS REGION

O: 16MAR2018 09:25:01  56.5S   25.7W mb=5.6  ANSS   the South Sandwich Islands

P: 12MAR2018 115326    58.0S   25.0W 4.0-5.8 BBAAA  So. Sandwich Islands       

 

The strongest earthquake in the U.S. or Canada today was an M 4.0 off the coast of Oregon. This event occurred well offshore and was not associated with damage or tsunami. NEIC reported this earthquake of M 4.0 in Oregon was felt with intensity II-III in the area(s) of Oregon at Florence, Corvallis and in White Rock, British Columbia. The last earthquake within about 100 km of this epicenter with M>=4 occurred on January 28, 2018 and prior to that on October 13, 2017 with M 4.5. Today's event may have been promoted by the nor'easter which hit the northeastern North American coast over the past several days.  Forecast 115226 had expected this earthquake was likely within about 100 km of this epicenter around March 19.

 

O: 16MAR2018 08:23:23  44.0N  129.0W mb=4.0  ANSS   the coast of Oregon          

P: 19MAR2018 115226    44.5N  129.8W 3.0-4.7 BAAAA  Off Coast of Oregon        

 

California was at extremely quiet conditions today with no earthquakes of M>=2.3 recorded. This is not good news as very quiet conditions such as this can be a seismic quiescence preceding moderate to large regional events.  The quiet period in California has now persisted for the past three days and is likely to break with the new moon and the geomagnetic storm today.

 

MODERATE QUAKES SHAKE TRINIDAD AND TOBAGO AND ICELAND

 

EARTHQUAKE SUMMARY FOR MARCH 15, 2018

 

There were no moderately large earthquakes in the world today. The maximum  events occurred with M 4.8-5.2, mostly in the Philippines and Indonesia and were continuing stress redistribution in that area following the PNG event of February 25. An M 5.0 also occurred in Trinidad and Tobago. The most unusual quake in the world in this magnitude range today was an M 4.8 north of Iceland. The Trinidad quake followed minutes after the event in Iceland and may have been promoted by seismic energy from that event. This summary had expected this event in the Iceland region in the previous issues as:

 

 

"The new moon will arrive on March 17 at 13:12 UT. Longitudes at local solar noon at this time center on 17 West longitude and include areas of the Atlantic Ocean from Iceland, the Canary Islands and Ascension Island among other. These, including some areas off the coast of Spain and Portugal and the Strait of Gibraltar could see elevated seismicity in the next week, and some such the Ascension Island area have already seen moderately large earthquakes. Iceland is especially vulnerable to tidal effects at this time. In the east local solar midnight is centered at 163 East longitude and includes Vanuatu, New Zealand, the Solomon Is. And eastern Papua New Guinea in the south and the Kamchatka-Komandorsky-Rat Islands to the north. These are the regions most likely to see tidal triggering in the next week, but global seismicity is likely to be high during this period outside these zones as well." (March 15, 2018)

 

The last earthquake in this area of Iceland with M>=4.8 occurred on February 19, 2018 with M 4.8 and 5.0 with the last new moon and prior to that on March 26, 2017 (M 4.9). Forecast 115268 had expected this event within about 150 km was likely around March 16 in Iceland.

 

O: 15MAR2018 10:56:35  66.3N   19.3W ML=4.8  EMSC   ICELAND REGION               

P: 16MAR2018 115268    65.0N   16.0W 3.0-4.8 AAAAA  Iceland area                

 

An earthquake of M 5.0 also occurred in the region of Trinidad and Tobago today. EMSC reported this earthquake of M 5.0 in Trinidad and Tobago was heard and felt with intensity II-III in the area(s) of Diego Margin, Trinidad and Tobago.  NEIC reported intensity II-III in Diego Martin at Mucurapo; in Port of Spain; unapuna and Piarco and Tacarigua and in Sangre Grande, Trinidad and Tobago. This is the strongest earthquake within about 200 km of this epicenter since an M 5.4 on November 5, 2017 and prior to that an M 5.9 on December 6, 2016. Forecast 115120 had expected this event within about 100 km was likely around March 18.

 

O: 16MAR2018 02:49:51  10.9N   62.2W ML=5.0  EMSC   OFFSHORE SUCRE, VENEZUELA    

P: 18MAR2018 115120    11.0N   63.0W 3.4-5.3 AAAAA  Windward Islands           

 

A moderate earthquake of M 4.5 also occurred today in the Virgin Islands region of the northern Caribbean, but was not reported felt. The last earthquake in the Virgin Islands of M>=4.5 occurred on February 9, 2018 (M 4.5) and prior to that on December 24, 2017 (M 5.2).  This region has shown seismic unrest in recent weeks since the M 8.0 in the  Gulf of Alaska of January 23 and may be promoted from that source as it is at the fifth node (72 degrees) from Alaska. Forecast 115106 had expected today's event was likely around March 15.

 

O: 15MAR2018 06:57:09  18.7N   64.8W MD=3.4  EMSC   VIRGIN ISLANDS REGION        

O: 15MAR2018 11:13:28  18.8N   64.6W mb=4.5  EMSC   VIRGIN ISLANDS REGION        

P: 15MAR2018 115106    19.0N   64.0W 3.0-5.0 AAAAA  Leeward Islands            

 

The largest earthquake in California today was an M 3.2 east of Los Angeles near

Joshua Tree and Sky Valley, California. This is at 103 degrees from Papua New Guinea and is located in a region where strong seismic promotion from PNG is expected in the next two weeks. Earthquakes within about 50 km of this epicenter of M>=3 are unusual. The last such event of M>=3.2 occurred half a year ago on September 21, 2017 with M 3.2-3.3. The last of larger magnitude was an M 3.4 on September 24, 2016. Forecast 115179 had expected  today's event was likely around March 12.

 

O: 16MAR2018 04:04:48  34.0N  116.3W ml=2.0  ANSS   Joshua Tree CA               

O: 16MAR2018 04:08:01  34.0N  116.3W ml=3.2  ANSS   Sky Valley California        

P: 12MAR2018 115179    33.7N  116.1W 2.5-4.4 BAAAA  So. California             

 

Also at 103 degrees from PNG an earthquake of M 3.8 was reported in Eastern Turkey. This is another area being watched for signs of a coming moderate event. The last event of M>=3.8 in the area was an M 4.0 on August 9, 2017. Forecast 115192 had expected this event was likely within about 100 km of this epicenter around March 12.

 

O: 16MAR2018 02:35:13  38.9N   43.6E ML=3.8  EMSC   EASTERN TURKEY               

O: 15MAR2018 14:26:21  39.7N   43.6E ML=3.2  EMSC   EASTERN TURKEY               

P: 12MAR2018 115192    38.0N   43.0E 3.5-4.9 BAAAA  Turkey                     

 

The strongest earthquake in the U.S. or Canada today was an M 3.9 aftershock in the Gulf of Alaska. This was not reported felt and is a nearly daily event at this point in the aftershock sequence.

 

O: 15MAR2018 11:46:52  56.7N  148.5W Ml=3.2  EMSC   GULF OF ALASKA               

O: 15MAR2018 22:26:02  56.6N  148.7W ml=3.9  ANSS   ESE of Kodiak Alaska

P: 15MAR2018 115241    56.0N  150.9W 3.5-5.0 AAAAA  Gulf of Alaska             

 

 

 

NEW MOON COULD PROMOTE SEISMICITY IN ATLANTIC; SOUTHWEST PACIFIC

 

EARTHQUAKE SUMMARY FOR MARCH 14, 2018

 

A light earthquake of M 3.5 occurred in the region of Iceland today. This continues seismicity in the region which has been off-and-on over the past several weeks. This tends to see larger magnitudes near times of new and full moons and is probably promoted by tidal stresses acting on local magma bodies. Further and larger quakes can occur in the next several days in conjunction with the new moon of March 17.

 

The new moon will arrive on March 17 at 13:12 UT. Longitudes at local solar noon at this time center on 17 West longitude and include areas of the Atlantic Ocean from Iceland, the Canary Islands and Ascension Island among other. These, including some areas off the coast of Spain and Portugal and the Strait of Gibraltar could see elevated seismicity in the next week, and some such the Ascension Island area have already seen moderately large earthquakes. Iceland is especially vulnerable to tidal effects at this time. In the east local solar midnight is centered at 163 East longitude and includes Vanuatu, New Zealand, the Solomon Is. and eastern Papua New Guinea in the south and the Kamchatka-Komandorsky-Rat Islands to the north. These are the regions most likely to see tidal triggering in the next week, but global seismicity is likely to be high during this period outside these zones as well.

 

Forecast 115268 had expected this event within about 35 km was likely around March 16. This event is at the third node (120 degrees) from PNG and may have been promoted from that source.

 

O: 14MAR2018 21:10:34  65.0N   16.7W ML=3.5  EMSC   ICELAND                      

P: 16MAR2018 115268    65.0N   16.0W 3.0-4.8 AAAAA  Iceland area               

 

The strongest earthquake in the U.S. or Canada today outside Alaska occurred in a minor swarm in Southern Idaho in the Borah Peak region. There were no reports of damage with these earthquakes which spread about 100 km.  This activity occurred at 103 degrees from the PNG M 7.6 of February 25. Seismic energy is concentrated on the surface at this distance from major quakes and and may help promote regional seismicity. This report has been watching events at this distance from PNG in recent days including in Southern California, Nevada, Idaho, the East African Rift and eastern Turkey. A strong earthquake in one or more of these areas could be promoted by energy from PNG.

 

The last earthquake of M>2.8 in this region of Southern Idaho occurred  on December 21, 2017 with M 2.9. The last of significantly larger magnitude was an M 3.6 on February 28, 2016. The last event larger than and within about 100 km of today's M 2.8 occurred on  August 21, 2010 with M 3.6. Forecast 115213 expected today's activity as a regional event around March 16.

 

O: 14MAR2018 17:06:40  44.0N  115.2W ML=2.8  EMSC   SOUTHERN IDAHO               

O: 14MAR2018 17:04:51  44.3N  114.6W ML=2.1  EMSC   SOUTHERN IDAHO               

O: 14MAR2018 17:01:59  44.3N  114.6W ML=2.6  EMSC   SOUTHERN IDAHO                

P: 16MAR2018 115213    45.7N  112.1W 2.0-3.9 ABBAA  Montana/Idaho              

 

The strongest earthquakes in the world today occurred in the Tonga/Vanuatu/Loyalty Islands of the southwest Pacific region. These appear to be related to stresses associated with a series of tropical cyclones which have hit the region in the past week. For example this summary noted on March 12:

 

"A tropical cyclone may be forming south of the Solomon Islands. This system is expected to track directly south from its current position at 13S 159E with winds up to 32 kts and may bring increases in seismicity to the area from the Solomon Islands to Vanuatu while it is in progress." (March 12, 2018)

 

And on March 10, it was noted:

 

"Tropical Cyclone Hola (12P) continued today in the region of the Loyalty Islands with winds up to 100 kts. It could help promote seismicity (along with high tides) in the Central and southern Vanuatu and Loyalty Islands regions. It is expected to track to the south reaching North Island, New Zealand around March 12 with winds up to 100 kts. This could help trigger a moderate earthquake in the region of North and/or South Island around March 11-14." (March 10, 2018) 

 

The strongest of today's events was an M 5.1 in the Loyalty Islands.

 

O: 15MAR2018 01:26:23  10.9S  166.0E mb=4.8  EMSC   SANTA CRUZ ISLANDS           

P: 21MAR2018 115294    14.0S  168.0E 4.0-5.6 CCBAA  Vanuatu Islands            

 

O: 15MAR2018 04:51:09  13.8S  167.3E mb=4.5  EMSC   VANUATU                      

P: 21MAR2018 115294    14.0S  168.0E 4.0-5.6 CAAAA  Vanuatu Islands            

 

O: 15MAR2018 06:48:21  21.5S  170.4E Mw=5.1  EMSC   SOUTHEAST OF LOYALTY ISLANDS 

P: 17MAR2018 115298    22.0S  169.0E 4.0-5.5 AAAAA  Loyalty Islands            

 

O: 14MAR2018 20:13:37  21.9S  174.8W ML=4.9  EMSC   TONGA                        

P: 19MAR2018 115305    20.0S  174.0W 4.0-5.7 BBAAA  Tonga Islands              

 

O: 14MAR2018 20:14:35  22.7S  179.5W mb=4.7  EMSC   SOUTH OF FIJI ISLANDS        

P: 16MAR2018 115306    22.0S  180.0W 4.0-5.4 AAAAA  Tonga Islands              

 

 

UNUSUAL MODERATE QUAKES IN NAMIBIA AND ROMANIA

 

EARTHQUAKE SUMMARY FOR MARCH 13, 2018

 

An unusual earthquake of M 4.8 hit the region of Namibia in Southern Africa today. It was not reported felt or damaging in this remote area. The last earthquake within about 500 km of this epicenter in or near Namibia occurred on March 24, 2012 with M 4.8. Two other such events have occurred in this region since 1990 - an M 5.1 on July 31, 2009 and an M 4.8 on April 26, 2008. A series of earthquakes in Mozambique, Tanzania and Malawi occurred last week following the M 7.6 in Papua New Guinea at 103-104 degrees from that strong quake. Today's event is not at this distance from PNG (it is at the third node - 120 degrees). However, like the events in Mozambique it is located at 142 degrees from the great M 8.0 in the Gulf of Alaska of January 23. Seismic energy from major earthquake reflects and refracts off core boundaries and returns to the surface at this distance from the major event. As seismicity in this distance zone increases in the days following, it is likely promoted by this concentrated energy. The Namibia epicenter is also at 103 degrees from the M 7.6 north of Honduras of January 10, 2018. Energy reflected from core-mantle boundaries returns to the surface at this distance and probably triggers zonal earthquakes at this distance. Areas of eastern Turkey are at 103 degrees from PNG and Honduras. A strong quake hit this area of Turkey on March 13, 1992, 28 years ago. Southern California and the Gulf of California (M 4.2) also showed continuing activity at this distance from PNG today.

 

O: 14MAR2018 08:32:47  19.8S   14.7E mb=4.8  EMSC   NAMIBIA                      

 

An M 4.5 earthquake at intermediate depth was widely felt within about 250 km of the epicenter in Romania today. NEIC reported it was felt with intensity II-III in Romania at Ploiesti, Stefanestii de Jos, Voluntari, Bucharest, Chiaina, Iasi, among other communities. There is a pocket of seismicity deep beneath Romania which occasionally produces earthquake of moderate size felt on the surface and is capable of large earthquakes. The last earthquake of M>=4.5 in this area of Romania was an M 4.7 on August 2, 2017 and prior to that an M 4.7 on February 8, 2017. The last of M>5 was an M 5.6 on December 27, 2016.  Forecast 114958 had expected today's earthquake was likely within about 50 km of this epicenter around March 11. This earthquake is at the fourth node  (90 degrees) from the M 7.6 in Honduras of January 10, 2018 and was probably promoted from that source.

 

O: 14MAR2018 10:24:48  45.7N   26.6E mb=4.5  EMSC   ROMANIA                      

P: 11MAR2018 114958    46.0N   26.0E 3.0-5.0 BAAAA  Romania/NW Turkey          

 

The strongest earthquake in the world today was an M 5.2 in Central Peru. NEIC reported this earthquake of M 5.2 in Central Peru was felt with intensity V in Oxapampa, and IV in Huanuco and II-III in the area(s) of Satipo, Pucallpa and Lima, Peru. This is the largest earthquake in central Peru within about 200 km of this epicenter since an M 5.7 on October 30, 2017 but is probably not an aftershock of that earthquake which occurred 60 km deeper than today's event. It occurred within about 30 minutes of local solar noon and may have been promoted by tidal stresses which maximize at this hour. Forecast 115281 had expected this event was likely within about 30 km of the epicenter around March 16.

 

O: 13MAR2018 17:35:04  10.3S   75.0W mb=5.2  EMSC   CENTRAL PERU                 

P: 16MAR2018 115281    10.0S   75.0W 3.5-5.0 BAAAA  Brazil                      

 

The strongest earthquake in the U.S. or Canada today occurred as an M 4.7 in the eastern Andreanof Islands, Alaska. It was not reported felt in this remote epicentral area. This continues the moderate activity in  the Andreanof Islands of the past week where the strongest activity in the U.S. has occurred nearly every day. This is probably due to strong weather patterns in the area at this time of year which can help promote larger earthquakes in the area. The last earthquake within about 100 km of this event with M>=4.7 occurred December 28, 2017 with M 4.7 but the last of greater magnitude was an M 4.9 on December 9, 2017. Forecast 115243 expected today's event within about 50 km of the epicenter was likely around March 14. 

 

O: 14MAR2018 10:42:28  52.1N  174.9W mb=4.7  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P: 14MAR2018 115243    52.4N  174.3W 3.5-5.2 AAAAA  Andreanoff Isls, Aleutians 

 

A pattern was setting up in southern California today which suggested preliminary activity which could lead to a moderate quake in the area in the last part of March. At M 2.3 each this series looks like triggered activity from PNG but could expand to a larger event to the north in western Los Angeles or to the east in eastern Los Angeles, California where a swarm of light quakes also continued. Each of these had been anticipated in forecasts in this summary. The previous issue of this summary had anticipated this pattern as:

 

" ... reflect precursory regional activity at 102 degrees from the M 7.6 in

Papua New Guinea (PNG) of February 25, 2018.  The most likely date of a possible moderate to large regional quake triggered from PNG is still anticipated in late March. If this is a repeat of the San Fernando Valley quake of 1971 and/or Northridge of 1994, a series of smaller events should precede it beginning south of Los Angeles in the Santa Monica area and slowly migrate over the course of a week to the north into the Simi Valley area. Today's trio of events in eastern Los Angeles is not part of this pattern but probably reflects triggering from PNG. The remnants of Tropical Cyclone Dumazile in the South Indian Ocean are directly antipodal to southern California at this time as well and  antipodal concentration of energy from that storm may help promote seismicity ..." (March 12-13, 2018)

 

NEIC reported this earthquake of M 2.0 in Los Angeles, California was felt with intensity II-III in the area(s) of Manhattan Beach, El Segundo, Hermosa Beach, Los Angeles, Redondo Beach, Playa del Rey, California. A second quake of M 2.0 was later felt with similar intensities in the same area. The largest event in this series was an M 2.3 today reported with intensity II-III within about 25 km of the epicenter near Manhattan Beach. This activity is occurring south of the valleys west of Los Angeles and could be precursory to larger regional activity. An event of M 2.3 in the Malibu region was also felt today with intensity IV in Agoura Hills and II-III in Malibu, Calabasas, Westlake Village and Thousand Oaks, California.

 

O: 14MAR2018 08:08:50  33.9N  118.4W ML=2.1  EMSC   SANTA MONICA BAY, CALIFORNIA 

O: 13MAR2018 12:38:26  33.9N  118.4W ML=2.3  EMSC   SANTA MONICA BAY, CALIFORNIA 

P: 11MAR2018 114913    33.6N  118.5W 2.5-4.5 AAAAA  So. California             

 

O: 13MAR2018 12:53:50  34.0N  117.0W ML=2.0  EMSC   SOUTHERN CALIFORNIA          

P: 18MAR2018 115179    33.9N  116.9W 2.5-4.5 BAAAA  So. California             

 

O: 13MAR2018 13:41:49  34.1N  117.9W ML=2.3  EMSC   GREATER LOS ANGELES AREA, CALI

P: 13MAR2018 115180    34.3N  117.5W 2.5-4.5 AAAAA  So. California             

 

O: 14MAR2018 02:18:20  34.1N  118.8W ML=2.3  EMSC   GREATER LOS ANGELES AREA, CALI

P: 14MAR2018 115182    34.3N  118.5W 2.5-4.5 AAAAA  So. California             

 

O: 14MAR2018 04:17:18  34.1N  119.3W ML=2.3  EMSC   SANTA BARBARA CHANNEL, CALIF.

P: 15MAR2018 115181    33.8N  119.7W 2.5-4.6 AAAAA  So. California             

 

 

SUMATRA SHAKES ON QUIET DAY

 

EARTHQUAKE SUMMARY FOR MARCH 12, 2018

 

The strongest, and only earthquake in the world today of M>=5 occurred in  Northern Sumatra, Indonesia. It was reported lightly felt in the epicentral region without damage. This area has been active since the events of Papua New Guinea and Alaska as it is lies near 103 degrees from the Gulf of Alaska quake of January 23, 2018 and is probably being promoted from that source.  Forecast 115066 had expected this event within about 200 km was likely around March 13.

 

O: 13MAR2018 04:33:38   2.0N   98.9E mb=5.0  EMSC   NORTHERN SUMATRA, INDONESIA  

P: 13MAR2018 115066     1.0N   97.0E 4.0-5.6 AABAA  Nicobar Islands            

 

The strongest earthquake in the U.S. or Canada today was an M 4.3 in southern Alaska. NEIC reported it was felt with intensity II-III in Homer, Anchor Point, Soldotna, Sterling and Anchorage, Alaska. This is the strongest earthquake in the Kenai Peninsula since an M 4.4 on November 17, 2017. Forecast 115264 had expected this event was possible around March 16.

 

O: 13MAR2018 03:22:24  59.2N  152.0W mb=4.2  EMSC   KENAI PENINSULA, ALASKA      

O: 12MAR2018 21:44:47  59.5N  149.8W ML=3.2  EMSC   KENAI PENINSULA, ALASKA      

P: 16MAR2018 115264    60.7N  151.8W 3.2-5.1 BBAAA  Central Alaska             

 

A swarm of light earthquakes of M 2.0-2.3 occurred in eastern Los Angeles today. These were not reported felt or damaging in their epicentral area. They may,  however reflect precursory regional activity at 102 degrees from the M 7.6 in Papua New Guinea (PNG) of February 25, 2018.  The most likely date of a possible moderate to large regional quake triggered from PNG is still anticipated in late March. If this is a repeat of the San Fernando Valley quake of 1971 and/or Northridge of 1994, a series of smaller events should precede it beginning south of Los Angeles in the Santa Monica area and slowly migrate over the course of a week to the north into the Simi Valley area. Today's trio of events in eastern Los Angeles is not part of this pattern but probably reflects triggering from PNG. The remnants of Tropical Cyclone Dumazile in the South Indian Ocean are directly antipodal to southern California at this time as well and  antipodal concentration of energy from that storm may help promote seismicity in Southern California at this time. The last similar activity within about 30 km of these epicenters occurred on October 14, 2017 with M 2.2-2.3. Forecast 115180 had expected this activity about 30 km to the east around March 13.

 

O: 12MAR2018 20:16:46  34.2N  117.9W Ml=2.0  EMSC   SOUTHERN CALIFORNIA          

O: 12MAR2018 15:00:24  34.3N  117.8W ML=2.1  EMSC   SOUTHERN CALIFORNIA          

O: 12MAR2018 16:40:29  34.4N  117.8W ML=2.0  EMSC   SOUTHERN CALIFORNIA          

P: 13MAR2018 115180    34.3N  117.5W 2.5-4.5 AAAAA  So. California             

 

SOLAR FLARE COMING?

 

EARTHQUAKE SUMMARY FOR MARCH 11, 2018

 

The Russian Academy of Sciences is predicting that a major solar flare is likely to occur around March 18. This summary has no independent evidence for or against this occurrence but global seismicity is likely to be high at this time. The new moon will also arrive at this time. Stresses and effects from these two sources could help promote a major earthquake in the period from March 17-23. The most likely areas to watch at this time are the southwest Pacific and the northwestern Pacific Rim. A moderate earthquake in Southern California east of Los Angeles or in the Nevada area is also  possible at that time.

 

While it was a relatively quiet day in global seismicity, the moderate quakes that did occur tended to the Indian Ocean. None of these were felt in the region and they all occurred within about half an hour of local solar noon, implicating tidal stresses as a promoting factor. These events had been  expected within about 50 km of the epicenters in early March for the northern mid-Indian Ridge event of M 4.8 and the Southeast Indian Ridge event of M 5.1. The third event of M 5.0 between these had been anticipated with less accuracy to occur around March 7. Some of this activity is near the path of Tropical Cyclone Dumazile which passed over this area last week and probably helped promoted some of this seismicity. The antipode of the remnants of Dumazile is in Southern California, which could see a moderate event in the next two weeks.

 

O: 12MAR2018 07:17:55  16.5S   67.3E mb=4.8  EMSC   MID-INDIAN RIDGE             

P: 10MAR2018 115013    17.0S   67.0E 4.0-5.5 AAAAA  So. Indian Ocean           

 

O: 12MAR2018 07:25:02  25.6S   70.0E mb=5.0  EMSC   MID-INDIAN RIDGE             

P:  7MAR2018 115031    28.0S   66.0E 4.0-5.6 BCCAA  So. Indian Ocean           

 

O: 12MAR2018 06:13:48  46.4S   96.0E mb=5.1  EMSC   SOUTHEAST INDIAN RIDGE       

P:  5MAR2018 115048    46.0S   96.0E 4.0-5.6 CAAAA  So. Indian Ocean           

 

A pair of light earthquakes of M 2.7 and 3.4 hit near Hollister, California today. NEIC reported they were felt with intensity IV in Hollister and II-III in San Juan Bautista, Gilroy, Aromas,  Watsonville, Morgan Hill, San Jose, Monterey, Pebble Beach, Los Altos, California. These follow a series about 200 km to the southeast of M 3.7 and 3.4 on March 7 and 8 but are the strongest within about 35 km of this epicenter since an M 4.6 on November 13, 2017. Forecasts 114885 and 114885 had expected the area would be active in early March.

 

O: 11MAR2018 18:10:35  36.9N  121.4W ML=2.7  EMSC   CENTRAL CALIFORNIA           

O: 11MAR2018 18:09:08  36.9N  121.4W ML=3.4  EMSC   CENTRAL CALIFORNIA           

P:  3MAR2018 114885    36.7N  121.4W 2.5-4.8 CAAAA  Central California         

P:  9MAR2018 114884    36.2N  120.8W 2.5-5.0 AAAAA  Central California         

 

An M 3.4 also occurred in southern California near Ocotillo at 103 degrees from PNG and was probably promoted from that source. NEIC reported the California event was felt with intensity III in California at Thermal, Julian and El Cajon and possibly other communities in southern California. An earthquake southeast of this in Baja was noted in the previous issue of this summary as:

 

"Activity in the region 32-33N 115-116W in Baja California has been relatively quiet in recent weeks an months, so while not obviously so, the M 3.2 in Baja today was unusual, the first of that size or larger in this area since November  3, 2017 and may represent triggering from PNG at a distance of 103 degrees away" (March 9-10, 2018)

 

22  33.2N  116.0W ML=3.4  EMSC   SOUTHERN CALIFORNIA          

 

Today's M 3.4 is the strongest within about 50 km of this epicenter since an M 3.6 on  January 13, 2018 and prior to that an M 4.0 on December 7, 2017.

Forecasts 114912 and 114910 had expected today's activity around March 8-11.

 

O: 11MAR2018 12:45:22  33.2N  116.0W ML=3.4  EMSC   SOUTHERN CALIFORNIA          

P:  8MAR2018 114912    32.8N  116.0W 2.5-4.4 BAAAA  So. California             

P: 11MAR2018 114910    32.4N  115.8W 2.5-4.5 AAAAA  So. California             

 

The strongest earthquake in the U.S. or Canada today was an M 4.4 in the central Andreanof Islands, Aleutians. It was not reported felt in this remote area. This is part of an increase in seismicity in the Andreanof Islands which has been notable in the past several days. It is probably an aftershocks of the M 4.8 which occurred north of this epicenter on March 8. Forecast 114970 had expected this event within about 100 km of this epicenter was likely around March 6.

 

O: 11MAR2018 17:44:37  50.4N  177.4W mb=4.4  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P:  6MAR2018 114970    51.3N  176.8W 3.5-5.2 BAAAA  Andreanoff Isls, Aleutians 

 

A series of light to moderate earthquakes also occurred in the Virgin Islands region today. The largest of these was an M 4.1. They were not reported felt but may have been promoted from the M 6.8 in New Ireland and the M 7.6 in PNG near 145 degrees away. These events are also at the fifth node (72 degrees) from the great M 8.0  quake in Alaska of January 23 which probably set the region up for this increased seismicity. The last events of larger magnitude in the area of the Virgin Islands occurred on February 9 (M 4.9) and on January 7, 2018 (M 4.4). Forecast 114851 had expected today's activity around March 8.

 

O: 11MAR2018 21:25:52  19.2N   64.6W MD=3.5  EMSC   VIRGIN ISLANDS REGION        

O: 11MAR2018 21:12:01  19.2N   64.7W MD=4.1  EMSC   VIRGIN ISLANDS REGION        

O: 11MAR2018 07:06:00  19.3N   65.0W MD=3.1  EMSC   VIRGIN ISLANDS REGION        

O: 11MAR2018 21:52:09  19.3N   65.1W MD=3.6  EMSC   VIRGIN ISLANDS REGION        

O: 12MAR2018 02:38:03  19.5N   64.4W MD=3.2  EMSC   VIRGIN ISLANDS REGION        

P:  8MAR2018 114851    18.0N   65.0W 3.0-4.9 BBAAA  Leeward Islands            

 

ATLANTIC ROCKED BY MODERATELY LARGE QUAKES

 

EARTHQUAKE SUMMARY FOR MARCH 10, 2018

 

A pair of moderately large earthquakes occurred today under the Atlantic Ocean. The first of these was an M 5.5-5.6 in the South Sandwich Islands. That was followed by an M 5.9 in the Ascension Island area of the central Atlantic. Neither of these events was reported felt in these remote regions and no tsunami was expected nor observed. The earthquake in Central Atlantic regions may have been promoted by the strong seismicity in Papua New Guinea and New Ireland/New Britain as it is located in the antipodal area of those events. A more true antipodal  disturbance passed in northern Vanuatu last week and may have more likely help promote today's event - Tropical Cyclone Hola. This antipodal relation had been pointed out in this summary over the past several days but was not considered close enough to trigger a strong event such as occurred today. It is not uncommon for strong or major events in PNG to Vanuatu to be followed shortly by strong or moderately strong quakes in the Central Atlantic however and this antipodal relation has also been noted in this summary in past reports. The last quake of M>=5.9 in the Ascension Island region within about 200 km  of today's epicenter occurred on August 18, 2017 with M 6.0 and prior to that on November 29, 2011 with M 5.9. Forecast 114818 had expected today's event in the Ascension Island area was likely around March 7 within about 100 km of this epicenter.

 

O: 10MAR2018 21:45:37   1.4S   15.2W Mw=5.9  EMSC   NORTH OF ASCENSION ISLAND    

O: 10MAR2018 21:45:36   1.4S   15.2W mw=5.9  ANSS   North of Ascension Island"

P:  7MAR2018 114818     1.0S   16.0W 4.0-5.7 BAAAA  Central Mid-Atlantic       

 

The M 5.5-5.6 in the South Sandwich Islands is not an unusual quake for the area. The last earthquake of M>=5.6 in the South Sandwich Islands occurred  on September 4, 2017 and prior to that on May 30, 2017.  The epicenter is located at the third node (120 degrees) from the M 6.8 in New Ireland of March 8 and was probably promoted from that source. Forecast 115055 had expected today's event was likely around March 6 to the northeast of today's epicenter. 

 

O: 10MAR2018 14:27:54  56.4S   28.0W Mw=5.5  EMSC   SOUTH SANDWICH ISLANDS REGION

O: 10MAR2018 14:27:56  56.3S   28.1W mw=5.6  ANSS   the South Sandwich Islands

P:  6MAR2018 115055    58.0S   25.0W 4.0-5.8 BBBAA  So. Sandwich Islands       

 

Today's activity saw several light quakes continuing at 103 degrees from PNG. These were located, as in past days, in Nevada, southern California and Eastern Turkey for the most part and the only event of M>=3 was an M 3.2 in Baja California. As the most probable date (in late March) for a sizable event in Southern California approaches, however, this summary will attempt to provide rapid analyses of upcoming activity.

 

Activity in the region 32-33N 115-116W in Baja California has been relatively quiet in recent weeks and months, so while not obviously so, the M 3.2 in Baja today was unusual, the first of that size or larger in this area since November 3, 2017 and may represent triggering from PNG at a distance of 103 degrees away. Forecast 114910 had expected today's event was likely around March 11.

 

NEIC reported this earthquake of M 3.2 in Baja, California was felt with intensity II-III in the area(s) of Bonita and Ontario, California.

 

O: 10MAR2018 22:20:39  32.2N  115.3W ML=3.2  EMSC   BAJA CALIFORNIA, MEXICO      

P: 11MAR2018 114910    32.4N  115.8W 2.5-4.5 AAAAA  So. California             

 

O: 10MAR2018 16:52:38  39.1N   40.3E ML=2.5  EMSC   EASTERN TURKEY               

P: 11MAR2018 114932    40.0N   41.0E 3.5-5.0 AAAAA  Caucasus/Caspian Sea       

 

NOR'EASTER MAY HAVE PROMOTED ALASKA, CALIFORNIA SEISMICITY

 

EARTHQUAKE SUMMARY FOR MARCH 9, 2018

 

The strongest earthquake in the U.S. or Canada today was an M 4.9-5.1 in Southern Alaska.  This, along with an M 4.5 off the coast of Northern California may have been promoted by motions of North America associated with landfall of a powerful nor'easter which hit the eastern seaboard of North America over the past two days. This summary had expected such a reaction in previous issues as:

 

"This may be a reaction to the nor'easter which hit the area several days ago. A very strong nor'easter is again expected around March 7-8 and could promote regional seismicity in the northeastern North American plate as well as moderate activity on the western boundaries of the North American plate." (March 6-7, 2018)

 

Moderate seismicity is still considered likely from areas off northern California to southern Alaska as promoted by the nor'easter." (March 8-9, 2018)

 

The earthquake in southern Alaska of M 4.9-5.1 was reported by NEIC to have been felt with intensity II-III in Alaska at Anchor Point, Ninilchik, Homer, Kasilof, Soldotna, Sterling, Kenai, Cooper Landing, Anchorage, Seward, Kenai, Cooper Landing, Seward, Willow, Girdwood, Eagle River, Wasilla, Chugiak, Palmer and Chignik, Alaska. Due to the intermediate depth (100 km) of this earthquake, no major damage was associated with the event, but it was widely felt in the area surround Anchor Point, Alaska. A similar M 5.1 shook the area on November 5, 2017 but the last event in the area within about 250 km of this epicenter was an M 5.4 on August 31, 2017. A major M 7.1 occurred about 50 km to the northwest of this on January 24, 2016 and today's event is probably one of the two largest aftershocks to date of that event (including the M 5.1 of November, 2017). Forecast 114992 had expected today's earthquake was likely around March 10.

 

O:  9MAR2018 18:23:44  59.5N  153.1W ML=3.0  EMSC   SOUTHERN ALASKA              

O:  9MAR2018 07:32:35  59.8N  153.1W Mw=4.9  EMSC   SOUTHERN ALASKA              

O: 09MAR2018 07:32:37  59.8N  153.1W ml=5.1  ANSS   Southern Alaska

P: 10MAR2018 114992    61.3N  152.3W 3.2-5.1 ABAAA  Central Alaska             

 

The M 4.5 off the coast of Northern California was reported felt with intensity IV in  California at Loleta and II-III in Petrolia, Ferndale, Rio Dell, Scotia, Fortuna, Hydesville, Whitethorn, Myers Flat, Redcrest, Redway, Eureka, Garberville, Samoa, Eureka, Arcata, Piercy, McKinleyville, Fort Bragg, Petaluma, Wilton and San Ramon. A small M 2.9 aftershock off the coast of northern California was reported by NEIC to have been felt with intensity II-III in Eureka and Fort Bragg, California. No major damage in California was reported with this offshore event and no tsunami was expected nor observed. The last earthquake of M>=4.5 within about 75 km of this epicenter off the coast of Northern California occurred on January 7, 2018 (M 4.5). The last event of M>4.5 in the area was an M 5.1 and M 4.6 aftershock on July 29, 2017 and prior to that an M 5.7 on September 3, 2016. Forecast 114950 had expected this event was likely within about 10 km of this epicenter around March 7.

 

O:  9MAR2018 06:01:27  40.3N  124.6W Mw=4.5  EMSC   OFFSHORE NORTHERN CALIFORNIA 

O: 10MAR2018 01:21:24  40.6N  124.3W MD=2.9  EMSC   NORTHERN CALIFORNIA          

O: 09MAR2018 06:01:28  40.3N  124.5W mw=4.5  ANSS   22km W of Petrolia

P:  7MAR2018 114950    40.3N  124.7W 2.5-4.6 AAAAA  Off Coast of No. Calif     

 

An unusual earthquake of M 3.6 also occurred today in Alberta ESE of Rocky Mt. House. While it was not reported felt in this remote area, it is located at 103 degrees from the epicenters of strong quakes in Papua New Guinea (PNG). This is a significant distance because a number of quakes around the world have apparently been triggered at that distance since the mainshock of M 7.6 on February 25. The last event within about 200 km of this epicenter listed by NEIC with M>=3.6 occurred on August 9, 2014 (M 4.3) and prior to that on November 12, 2007 (M 3.6).

 

O:  9MAR2018 16:48:07  52.2N  114.0W ML=3.6  NRCA  61 km ESE of Rocky Mt. House  

 

The strongest seismicity in the world today continued in the southwest Pacific Ocean area. An M 5.8 aftershock of yesterday's M 6.8 in New Ireland was recorded. An M 5.7 also occurred in the Fiji Islands and an M 5.4 in the Kermadec Islands. Tropical Cyclone Hola is currently in this area and, as suggested in previous summaries, is probably promoting seismicity in this region. Forecasts 115019 and 114824 had expected this activity in early March.

 

Tropical Cyclone Hola (12P) continued today in the region of the Loyalty Islands with winds up to 100 kts. It could help promote seismicity (along with high tides) in the Central and southern Vanuatu and Loyalty Islands regions. It is expected to track to the south reaching North Island, New Zealand around March 12 with winds up to 100 kts. This could help trigger a moderate earthquake in the region of North and/or South Island around March 11-14.  The antipode is at 18N 15W and is not a seismic region of the North Atlantic.

 

 

O:  9MAR2018 19:03:56   1.9S  152.5E mb=5.2  EMSC   NEW IRELAND REGION, P.N.G.   

O:  9MAR2018 11:06:06   4.3S  153.3E Mw=5.8  EMSC   NEW IRELAND REGION, P.N.G.   

P:  6MAR2018 114824     4.0S  153.0E 4.0-5.6 BAAAA  New Britain                

 

O:  9MAR2018 07:06:42  20.0S  175.3W mb=4.7  EMSC   TONGA                        

P:  2MAR2018 115034    20.0S  176.0W 4.0-5.7 CAAAA  Tonga Islands              

 

O:  9MAR2018 16:23:27  21.1S  178.8W Mw=5.7  EMSC   FIJI REGION                  

P:  8MAR2018 115019    19.0S  178.0W 4.0-5.6 ACAAA  Tonga Islands              

 

STRONG QUAKE SHAKES NEW IRELAND

 

EARTHQUAKE SUMMARY FOR MARCH 8, 2018

 

A strong earthquake of M 6.8 hit the region of New Ireland today. NEIC reported it was felt with intensity VI in Kokopo and V in Rabaul, East New Britain and II in Namatanai, New Ireland. There may be some tendency for global seismicity to shift about 10 degrees to the east following this earthquake, but this would be difficult to quantify. Today's event continues strong activation of the region within about 25 degrees of Papua New Guinea which began following the M 7.6 there on February 25. This has included several moderately strong earthquakes in the New Britain region including an M 5.6 on March 7 and an M 5.6 on February 26 - both about 200 km to the west of today's epicenter. The last earthquake of M>=6.8 within about 300 km of this epicenter occurred on December 17, 2016. This appears to be an aftershock of that event - the strongest to date. Forecast 114824 had expected this activity within about 50 km of this epicenter around March 6.

 

O:  8MAR2018 22:27:26   4.3S  152.9E mb=4.9  EMSC   NEW BRITAIN REGION, P.N.G.   

O:  8MAR2018 21:56:15   4.3S  153.3E mb=4.7  EMSC   NEW IRELAND REGION, P.N.G.   

O: 08MAR2018 17:39:50   4.4S  153.2E mw=6.8  ANSS   Taron Papua New Guinea

O:  8MAR2018 17:39:52   4.4S  153.3E Mw=6.8  EMSC   NEW IRELAND REGION, P.N.G.   

P:  6MAR2018 114824     4.0S  153.0E 4.0-5.6 AAAAA  New Britain                

 

 

An earthquake of M 4.7 also hit the region of Northern Tunisia today. NEIC reported it was felt with maximum intensity V in Ghar el Meleh, Binzart and IV in Binzart at Rafraf, Bardaw, Tunis, al-Hammah, Qabis; and II-III in Ariano, Halq el Oued, Tunis, Tunisia. This is the strongest earthquake northern Tunisia since an M 4.6 on August 29, 2015 and an M 4.7 on December 18, 2011. No major damage was reported with today's earthquake. Forecast 114927 had expected this event was likely to the west around March 8.

 

O:  8MAR2018 16:42:36  37.1N   10.3E mb=4.6  EMSC   TUNISIA                      

P:  8MAR2018 114927    37.0N    4.0E 3.0-4.6 AACAA  Western Mediterranean      

 

An unusual earthquake of M 5.2 was felt in Malaysia today. NEIC reported it with

intensity V in Sabah at Kota Belud and Ranau and IV in Dudat. Intensity II-III was felt in Donggongon, Kota Kinabalu, Kinarut, Papar, Malaysia. There were no reports of major damage or tsunami with this quake. This is an unusual epicenter, the last earthquake of M 5.2 within about 250 km of this epicenter having occurred in June, 2015 with M 6.0 and prior to that on May 23, 2005 (M 5.3). Today's event appears to be an aftershock of the June, 2015 activity.  Forecast 114802 had expected regional activity was likely around March 7.

 

O:  8MAR2018 13:06:13   6.0N  116.6E Mw=5.2  EMSC   SABAH, MALAYSIA               

P:  7MAR2018 114802     0.0N  122.0E 4.0-5.5 ACCAA  Celebes Sea                

 

A pair of moderate earthquakes of M 5.0 and 5.5 hit the southern Pacific Ocean today. The M 5.0 was in a highly unusual location at 104 degree from New Ireland. The last earthquake within about 250 km of this epicenter with M>=5.0 was an M 5.2 on March 24, 2015. Two other similar events hit the region in the past 28 years - an M 5.2 on February 25, 2013 and an M 5.0 on April 4, 2011. The last event within about 200 km of the M 5.5 on the West Chile Rise with M>=5.5 occurred on February 28, 2017 with M 5.6 and prior to that as an M 6.0 on July 27, 2016. Forecast 115046 had expected this activity was likely around March 7.

 

O:  8MAR2018 14:15:17  44.1S   81.8W Mw=5.5  EMSC   WEST CHILE RISE              

O:  8MAR2018 16:51:41  48.4S   87.4W mb=5.0  EMSC   SOUTHERN PACIFIC OCEAN       

P:  7MAR2018 115046    41.0S   88.0W 4.0-5.6 ACBAA  Chile Rise                 

 

The strongest earthquake in the U.S or Canada today was an aftershock of M 4.9 in the Gulf of Alaska. The last aftershock in the Gulf of Alaska with M>=4.9  occurred more than a month ago on February 5, 2018 with M 4.9 and prior to that as an M 5.1 on January 31. These are the only aftershocks of M>=4.9 in the Gulf of Alaska since the first three days following the M 8.0 in that region on January 23, 2018. The occurrence of this event at this time may have been promoted by the nor'easter hitting the east coast of North America as suggested in previous summaries:

 

"This may be a reaction to the nor'easter which hit the area several days ago. A very strong nor'easter is again expected around March 7-8 and could promote regional seismicity in the northeastern North American plate as well as moderate activity on the western boundaries of the North American plate." (March 6-7, 2018)

 

Moderate seismicity is still considered likely from areas off northern California to southern Alaska as promoted by the nor'easter.

 

O:  8MAR2018 23:04:22  55.5N  149.3W ML=3.6  EMSC   GULF OF ALASKA               

O:  9MAR2018 00:50:41  55.6N  149.2W mb=4.0  EMSC   GULF OF ALASKA               

O:  9MAR2018 00:37:16  55.8N  149.2W mb=4.9  EMSC   GULF OF ALASKA               

O:  8MAR2018 21:48:03  55.8N  149.3W ML=4.0  EMSC   GULF OF ALASKA               

P:  8MAR2018 114967    56.0N  149.0W 3.5-5.1 AAAAA  Gulf of Alaska             

 

MODERATELY STRONG QUAKE IN MOZAMBIQUE AT 104 DEGREES FROM NEW GUINEA

 

EARTHQUAKE SUMMARY FOR MARCH 7, 2018

 

A moderately strong M 5.5-5.6 earthquake hit the region of Mozambique/Malawi, Africa today. NEIC reported it was felt with intensity III-IV in Blantyre City and Mulanje, Malawi. An aftershock of M 5.2 occurred about an hour later in the same area of Mozambique. This epicenter is located at 104 degrees from the activity in Papua New Guinea (PNG) of recent dates. Seismic energy from large earthquakes travels into the earth, reflects and refracts off the core-mantle boundary and returns to the surface at 103-104 degrees from the mainshock epicenter. Seismicity in this distance zone often increases following such events and is likely triggered or promoted from that energy. A series of moderate earthquakes occurred north of this early this week in the region of Tanzania at 103 degrees from PNG and were discussed in earlier issues of this report. The last earthquake of M>=5.6 within about 300 km of this epicenter occurred on June 24, 2017 with M 5.6. This was the only other event within the area in the past 18 years at this magnitude level.  Forecasts 115031 and 115009 had expected this activity around March 9-11.  Tropical Cyclone Dumazile passed east of this epicenter over the past week and stresses from this may have helped promoted this seismic activity.

 

O:  8MAR2018 08:49:45  16.8S   35.4E mb=5.5  EMSC   MOZAMBIQUE                   

O: 08MAR2018 08:49:44  16.8S   35.4E mw=5.6  ANSS   NE of Nsanje Malawi

P:  9MAR2018 115031    22.0S   33.0E 4.0-5.6 ACCAA  So. Indian Ocean           

P: 11MAR2018 115009    18.0S   42.0E 3.0-4.6 BBCAA  Madagascar area            

 

The swarm of earthquakes in eastern Turkey at 103 degrees from PNG also continued today. Maximum size was up to M 3.5 in this series. This summary in watching regions at or near 103 degrees from PNG which have shown signs of increased seismicity following the M 7.6 there of February 25. These include areas of eastern Turkey, the Middle East, the East African Rift Valley, the northern East Pacific Rise, the Gulf of California and southern California north to Nevada and Idaho and northern portions of Canada. Some or all of these could see additional moderate or strong earthquakes in the next two to three weeks. Areas at or near 144 degrees from PNG, the other seismic energy zone of surface concentration include Haiti, Dominican Republic and Puerto Rico and areas of the north Atlantic west of Spain. Forecast 114924 had expected the activity in Eastern Turkey was likely within about 50 km of this epicenter around March 8.

 

O: 08MAR2018 02:35:20  38.8N   40.1E ML=2.9  EMSC   EASTERN TURKEY

O: 08MAR2018 04:33:16  38.8N   40.1E ML=3.5  EMSC   EASTERN TURKEY

O: 07MAR2018 05:15:59  39.1N   40.3E ML=2.9  EMSC   EASTERN TURKEY

O: 07MAR2018 05:08:23  39.1N   40.3E ML=3.3  EMSC   EASTERN TURKEY

O: 07MAR2018 07:58:42  39.3N   40.2E ML=4.0  EMSC   EASTERN TURKEY

O:  8MAR2018 02:57:32  38.8N   40.0E ML=2.6  EMSC   EASTERN TURKEY               

P:  8MAR2018 114924    39.0N   41.0E 3.5-5.3 AAAAA  Turkey                     

 

An earthquake of M 5.7 also occurred today in the Ceram area of Indonesia. No tsunami or damage was reported. BMG reported the M 5.4 was felt with intensity II in Bula, Maluku, Seram, Indonesia. The M 5.7 was reported felt with intensity III in Bula, Maluku, Seram, Indonesia. NEIC reported it was felt with intensity V in Amahai, Maluku, Indonesia. It followed a slightly smaller M 5.4 near the same area about 17 minutes earlier. The earthquake of M 5.7 is the largest within about 250 km of this epicenter since an M 6.3 about  300 km to the west on October 31, 2017.The last in the Seram area of M>=5.7 was an M 6.9 on December 9, 2015. Forecast 114589 had expected today's activity within about 100 km was likely in late February or early March.

 

O:  8MAR2018 04:01:49   3.3S  130.9E mb=4.9  EMSC   SERAM, INDONESIA             

O:  8MAR2018 03:51:07   3.4S  130.9E Mw=5.7  EMSC   SERAM, INDONESIA             

O: 08MAR2018 03:51:07   3.3S  130.9E mw=5.7  ANSS   E of Amahai Indonesia

O: 08MAR2018 03:33:57  03.3S  131.0E MS=5.4  BMG  Felt with intensity II

O: 08MAR2018 03:51:08  03.3S  131.0E MS=5.7  BMG  Felt with intensity III

O: 08MAR2018 03:33:56   3.4S  130.9E mw=5.4  ANSS   E of Amahai Indonesia

O:  8MAR2018 03:33:55   3.4S  131.0E Mw=5.4  EMSC   SERAM, INDONESIA             

P:  7MAR2018 114841     7.0S  131.0E 4.0-5.4 ACAAA  West Irian, PNG            

P: 28FEB2018 114589     3.0S  130.0E 4.0-5.4 CAAAA  West Irian, PNG            

 

Another moderately large earthquake occurred in New Britain today with M 5.6. NEIC reported it was felt with intensity III in Rabal, East New Britain and in Namatanai, New Ireland, PNG. This is part of the ongoing activity associated at near distances from PNG and follows several other such events in recent days including an M 5.6 on February 26, the day after the M 7.6 in PNG. The last event in the region in the past half year of larger size was an M 5.8 on December 29. Forecast 114826 had expected this event around March 6 within about 100 km of this epicenter.

 

O:  7MAR2018 13:49:18   5.4S  151.3E Mw=5.6  EMSC   NEW BRITAIN REGION, P.N.G.   

P:  6MAR2018 114826     6.0S  150.0E 4.0-5.6 AAAAA  New Ireland                

 

Moderate earthquakes also occurred in Southern Iran today with M 4.9 and 5.3.  EMSC reported they were felt lightly in Iran at Jiroft, and other areas near the epicenter. These events are located at 90 degrees (node 4) from the PNG activity and were probably promoted by it. This possibility had been noted in the previous summary as:

 

"Areas to the east, such as Iran lie at the fourth node from PNG (90 degrees) and could also be subject to triggering from PNG." (March 7-8, 2018)

 

The M 5.3 is the strongest earthquake in this region of Southern Iran within  about 200 km of this epicenter since an M 5.4 more than two years ago on January 22, 2016 and prior to that on February 2, 2014 with M 5.3. 

Forecast 114876 had expected this event within about 100 km was likely around

March 9.

 

O:  7MAR2018 14:46:11  28.0N   57.7E mb=5.3  EMSC   SOUTHERN IRAN                

O:  7MAR2018 14:50:20  28.0N   57.8E ML=4.9  EMSC   SOUTHERN IRAN                

P:  9MAR2018 114876    29.0N   58.0E 3.5-5.2 AAAAA  So. Iran/Persian Gulf      

 

Moderate aftershocks also continued in Papua New Guinea today. These were generally felt lightly with intensity II-III in Kiunga, Fly River and Mendi, PNG.

 

O:  8MAR2018 03:33:24   6.2S  142.9E mb=5.3  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O: 07MAR2018 07:36:55   6.3S  142.9E mb=4.9  EMSC   NEW GUINEA, PAPUA NEW GUINEA

O: 07MAR2018 18:11:06   6.4S  142.8E mb=5.0  EMSC   NEW GUINEA, PAPUA NEW GUINEA

O: 08MAR2018 04:59:49   6.5S  142.4E mb=5.0  EMSC   NEW GUINEA, PAPUA NEW GUINEA

O: 07MAR2018 19:07:26   6.6S  142.7E mb=4.6  EMSC   NEW GUINEA, PAPUA NEW GUINEA

P:  7MAR2018 114833     4.0S  143.0E 4.0-5.5 ABAAA  Papua New Guinea           

 

 

A moderate quake of M 4.5-5.0 shook regions of South Island near Christchurch today. GEONET reported this earthquake was felt with moderate intensity in northern South Island. 192 people reported feeling this event; 60 with weak intensity; 87 with light shaking; 41 moderate; 4 strong and none with extreme shaking. The last earthquake with M>=5 in South Island within about 150 km of this epicenter occurred on September 20, 2017 (M 5.0) with last of larger magnitude an M 5.4 on January 5, 2017 more than a year ago.   Forecast 115050 had expected this event within about 50 km of the epicenter was likely around March 3.

 

A moderate earthquake of M 4.4 also occurred in North Island, New Zealand today. GEONET reported this earthquake 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 134 people reported feeling this earthquake with 70 reports of weak intensity; 59 of light intensity; 5 with moderate; and none with strong to severe shaking. Forecast 115047 had expected this event within about 25 km of the epicenter was likely around March 9. This may be related to the approach of Tropical Storm Hola as noted in previous summaries:

 

"Tropical Cyclone Hola (12P) continued today in the region of central Vanuatu with winds up to 115 kts. It could help promote seismicity (along with high tides) in the Central and northern Vanuatu regions. It is expected to track to the south reaching North Island, New Zealand around March 12 with winds up to 100 kts. This could help trigger a moderate earthquake in the region of North and/or South Island around March 11-14." (March 6-7, 2018)

 

The earthquake in South Island was located at 103 degrees from the M 8.0 in Alaska of January 23, 2018 and was probably promoted from that source. Both quakes are at 101 degrees from Oaxaca, Mexico and the Gulf of Alaska. It is likely further activity in New Zealand will continue for the near term prompted by energy from these sources.

 

O:  7MAR2018 16:04:32  42.4S  173.5E mb=4.5  EMSC   SOUTH ISLAND OF NEW ZEALAND  

O: 07MAR2018 16:04:33  42.4S  173.44 ML=5.0  GEONET Felt with moderate intensity

P:  3MAR2018 115050    42.0S  173.0E 3.0-4.9 BAAAA  So. Island, N.Z.           

 

O:  7MAR2018 13:20:59  40.2S  174.8E MS=4.4  GEONET Felt with light intensity nort

P:  9MAR2018 115047    40.0S  175.0E 3.0-4.6 AAAAA  North Island, N.Z.         

 

A pair of light earthquakes of M 3.7 and M 3.5 were widely felt south of Parkfield, California today. NEIC reported the M 3.5 was felt with intensity II-III in Cayucos, Cambria, Templeton, Paso Robles, Morro Bay, Atascadero, Los Osos, Bradley, San Luis Obispo, San Miguel and Arroyo Grande, California.

This earthquake occurred within about 5 minutes of local solar midnight and was probably promoted by high tidal stresses which maximize at this hour. The M 3.7 was felt with similar intensities in California at Santa Margarita, Atascadero, Bakersfield, Cambria, Goleta and Santa Barbara, California. The last earthquake within about 50 km of the M 3.7 occurred February 8, 2015 more than two years ago with M 3.9 and prior to that on March 27, 2015 with M 4.1. Forecast 114884 had expected this event was likely within this area around March 8. The same forecast had expected the M 3.4 was likely around March 9. This activity is occurring about 100 km from PNG but still may related to that activity.

 

O:  7MAR2018 18:05:00  35.5N  120.0W Mw=3.7  EMSC   CENTRAL CALIFORNIA           

P:  8MAR2018 114884    36.1N  120.1W 2.5-4.9 AAAAA  Central California         

 

O:  8MAR2018 08:08:29  35.6N  120.9W ML=3.4  EMSC   CENTRAL CALIFORNIA           

P:  9MAR2018 114884    36.2N  120.8W 2.5-5.0 AAAAA  Central California         

 

The strongest earthquake in the U.S. or Canada today was an M 4.8 in the central Andreanof Islands, Alaska. It was not reported felt in this remote area. It follows a smaller event in the region yesterday of M 4.2. In the previous issue of this summary it had been noted as:

 

 

"An M 4.2 in the Andreanof Islands today was the largest earthquake in Alaska. This event was not reported felt in this region which is remote. The area often sees strong activation in the month of March, most likely due to strong weather patterns at this time of year and a strong quake in the Andreanof Islands is not unlikely in the next several weeks. The Fox and Unimak Islands are located at the fifth node (72 degrees) from PNG particularly in the western Fox Islands. These are the most likely to see a moderate to large quake promoted from PNG at this time. The last earthquake within about 150 km of today's Andreanof Islands event with M>=4.2 was an M 5.2 three weeks ago on February 16, 2018. A moderately large event hit the area on February 8, 2018 with M 5.6." (March 7, 2018)

 

O:  8MAR2018 03:10:39  51.3N  177.9W mb=4.8  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P:  6MAR2018 114970    51.3N  176.8W 3.5-5.2 AAAAA  Andreanoff Isls, Aleutians 

 

An unusual earthquake in New Hampshire of M 2.4 was not reported felt, but may be related to the nor'easter currently hitting the region. Forecasts 114945 and 114705 had expected a light quake within about 50 km of this epicenter was likely in early March.

 

O:  7MAR2018 10:07:40  43.3N   71.7W mb=2.4  EMSC   NEW HAMPSHIRE                

P:  2MAR2018 114945    44.0N   71.0W 2.0-4.4 BAAAA  New England                 

P: 28FEB2018 114705    43.0N   71.0W 2.0-4.4 CAAAA  New England                

 

EASTERN TURKEY STILL SHAKING

 

EARTHQUAKE SUMMARY FOR MARCH 6, 2018

 

An M 4.2 in Eastern Turkey several days ago was followed by a minor swarm in the region today including several events of M 4.0-4.5. Under normal circumstances this would not ring warning bells. But, like areas of southern California, this area is at 103 degrees from the Papua New Guinea quakes and could see a moderate or large earthquake. It is also at 103 degrees from the Honduras M 7.6 of January 10, 2018. Areas to the east, such as Iran lie at the fourth node from PNG (90 degrees) and could also be subject to triggering from PNG. At the time this summary noted:

 

"Unusual seismicity continued today at 103 degrees from the M 7.6 in Papua New Guinea of February 25. In addition to moderate earthquakes in Nevada, the Rocky Mountains, southern California other activity at this distance occurred in Tanzania and in eastern Turkey today. Seismic energy reflects and refracts off the core-mantle boundary and returns to the surface at this distance, often helping to promote zonal seismicity in regions which are seismic. It is likely that several large earthquakes will occur at this distance from PNG in the next month, as this is often the case following major events such as that." (March 3-4, 2018)

 

Other earthquakes today near 103 degrees from PNG included an M 4.9 on the northern East Pacific Rise and additional activity in the Baja and southern California regions.

 

O:  6MAR2018 20:34:35  38.4N   41.9E ML=2.8  EMSC   EASTERN TURKEY               

O:  7MAR2018 00:33:52  39.1N   40.3E mb=4.3  EMSC   EASTERN TURKEY               

P:  8MAR2018 114924    39.0N   41.0E 3.5-5.3 AAAAA  Turkey                     

 

A moderately strong earthquake occurred today in the southeastern Kuril Islands. This earthquake was not reported felt in this remote area and did not generate a reported tsunami. The area has been quiet since a series of of large events in 2010 ad 2012, the last of which was an M 7.2 on April 19, 2013. Forecast 114959 had expected this event was likely around March 5 within about 150 km of this epicenter. This epicenter is at the seventh node (52 degrees) from the PNG quakes and was likely promoted from that source. This summary had previously noted this relation as:

 

"The strongest earthquakes in the world outside PNG occurred today in the southern Kuril Islands. The largest of these was an M 5.4 which was not felt in this remote region ....  Today's activity is located at the fifth node from the PNG earthquakes (51 degrees) and was probably promoted from that source." (March 5, 2018) 

 

O:  7MAR2018 04:40:08  45.8N  152.3E Mw=5.8  EMSC   EAST OF KURIL ISLANDS        

P:  5MAR2018 114959    47.0N  151.0E 3.5-5.4 ABAAA  So. Kurils                 

 

A strong aftershock of M 6.7 hit the region of Papua New Guinea (PNG) today. This is the largest aftershock to date of the M 7.6 of February 25. NEIC reported it was felt with intensity VIII in Tari, Southern Highlands, IV in Porgera, Enga and Mount Hagen, Western Highlands; and II-III in Kiunga, Fly River and Jaya Pura, Papua, Indonesia.  BMG reported it at M 6.8 and that it was felt with intensity III-IV in Tanah Merah, Merauke, Wamena, Papua New Guinea.

It is likely that this event will continue to promote far-field seismicity, especially near 103 and 145 degrees. Forecast 114833 had expected a strong aftershock in PNG around March 3.

 

 

O: 06MAR2018 14:13:06   6.2S  142.6E Mw=6.7  EMSC   NEW GUINEA, PAPUA NEW GUINEA

O: 06MAR2018 14:13:10  06.2S  142.5E MS=6.8  BMG  Felt with intensity III-IV

O:  6MAR2018 22:46:23   6.1S  142.6E mb=4.4  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  6MAR2018 18:43:25   6.2S  142.5E mb=4.2  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  6MAR2018 14:13:06   6.2S  142.6E Mw=6.7  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  7MAR2018 00:25:25   6.3S  142.5E mb=4.7  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  6MAR2018 17:35:07   6.3S  142.6E mb=4.9  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  6MAR2018 14:50:53   6.3S  142.8E mb=5.1  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  6MAR2018 19:18:57   6.3S  142.9E mb=5.1  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  6MAR2018 16:35:13   6.4S  142.5E mb=4.1  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  6MAR2018 19:30:02   6.4S  142.6E mb=4.9  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  6MAR2018 15:35:32   6.4S  142.8E mb=5.2  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  6MAR2018 17:58:53   6.4S  142.9E mb=4.7  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  7MAR2018 01:36:40   6.4S  143.3E mb=4.5  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  6MAR2018 17:32:48   6.5S  143.3E mb=5.0  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  6MAR2018 18:46:22   6.6S  142.8E mb=4.9  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  7MAR2018 02:14:21   6.7S  143.5E mb=4.2  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  6MAR2018 14:40:03   7.0S  142.9E mb=5.0  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

P:  3MAR2018 114833     6.0S  142.0E 4.0-6.5 AAAAA  Papua New Guinea           

P:  4MAR2018 114832     5.0S  143.0E 4.0-5.4 AAAAA  Papua New Guinea           

 

An earthquake of M 4.5 occurred in the Puerto Rico Trench today. NEIC reported this earthquake of M 4.5 in Puerto Rico was felt with intensity II-III in the area(s) of Road Town, Tortola, Virgin Islands and San Juan, Puerto Rico.

The Puerto Rico Trench has not seen a major earthquake or tsunami since 1946, far beyond the average interevent period for such events in the region and such an event is likely in the short-term. The northern Caribbean has seen some major activity in recent years including the M 7.1 quake in Haiti which reportedly killed more than 250,000 and an M 6.4 in  Puerto Rico January 13, 2014. The last earthquake in the area of M>=4.5 occurred on February 9, 2018. The last of larger magnitude was an M 4.8 on August 18, 2017. Forecast 114866 had expected today's earthquake was likely within about 100 km of this epicenter around March 5. This epicenter is at 149 degrees from PNG and may have been promoted by concentrated energy from that source. It is also at the fifth node (72 degrees) from the great Gulf of Alaska M 8.0 of January 23, 2018 and was probably promoted from that source.

 

O:  6MAR2018 17:54:30  19.3N   65.3W mb=4.5  EMSC   PUERTO RICO REGION           

P:  5MAR2018 114866    20.0N   66.0W 3.0-4.5 AAAAA  Bahamas/No. Caribbean      

 

An earthquake of M 4.1 was widely felt in Oklahoma and Kansas today. NEIC reported it was felt with maximum intensity at Amorita, Oklahoma and II-IV in Oklahoma within about 100 km of the epicenter at Cherokee, Ringwood, Enid, and Dover and in Kansas at Conway Springs, Harper, Kiowa, and Medicine Lodge. This was the strongest earthquake in the U.S. or Canada today outside Alaska. Forecast 114921 had expected this event around March 3.

 

O:  6MAR2018 19:46:12  36.9N   98.3W mb=4.1  EMSC   OKLAHOMA                     

P:  3MAR2018 114921    37.0N   98.0W 2.0-4.0 BAAAA  Southern Plains            

 

An M 4.2 in the Andreanof Islands today was the largest earthquake in Alaska. This event was not reported felt in this region which is remote. The area often sees strong activation in the month of March, most likely due to strong weather patterns at this time of year and a strong quake in the Andreanof Islands is not unlikely in the next several weeks. The Fox and Unimak Islands are located at the fifth node (72 degrees) from PNG particularly in the western Fox Islands. Such an event could be promoted by the strong nor'easter about the hit the northeastern U.S. These are the most likely to see a moderate to large quake promoted from PNG at this time. The last earthquake within about 150 km of today's Andreanof Islands event with M>=4.2 was an M 5.2 three weeks ago on February 16, 2018. A moderately large event hit the area on February 8, 2018 with M 5.6. Forecast 114969 had expected today's event in the Andreanof Islands around March 8.

 

O:  6MAR2018 23:17:42  51.2N  178.5W ML=4.2  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P:  8MAR2018 114969    51.2N  179.9W 3.5-4.9 AAAAA  Andreanoff Isls, Aleutians 

 

STRONG AFTERSHOCK IN PAPUA NEW GUINEA

 

EARTHQUAKE SUMMARY FOR MARCH 5, 2018

 

A strong aftershock of M 6.7-6.8 hit the region of Papua New Guinea (PNG) today. This is the largest aftershock to date of the M 7.6 of February 25. NEIC reported it was felt with intensity IV in Porgera, Enga; and II-III in Kiunga, Fly River and Jaya Pura, Papua, Indonesia. It is likely that this event will continue to promote far-field seismicity, especially near 103 and 145 degrees. Forecast 114833 had expected a strong aftershock in PNG around March 3.

 

O: 06MAR2018 10:03:53   6.2S  142.4E mb=4.7  EMSC   NEW GUINEA, PAPUA NEW GUINEA

O: 06MAR2018 03:26:48   6.2S  142.4E mb=5.3  EMSC   NEW GUINEA, PAPUA NEW GUINEA

O: 06MAR2018 14:13:06   6.2S  142.6E Mw=6.7  EMSC   NEW GUINEA, PAPUA NEW GUINEA

O: 06MAR2018 02:52:31   6.3S  143.0E mb=5.0  EMSC   NEW GUINEA, PAPUA NEW GUINEA

O: 06MAR2018 12:01:25   6.4S  142.7E mb=4.8  EMSC   NEW GUINEA, PAPUA NEW GUINEA

O: 05MAR2018 11:47:15   6.5S  143.2E mb=4.7  EMSC   NEW GUINEA, PAPUA NEW GUINEA

O:  5MAR2018 12:35:06   5.8S  142.3E mb=4.2  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

P:  3MAR2018 114833     6.0S  142.0E 4.0-6.5 AAAAA  Papua New Guinea           

P:  4MAR2018 114832     5.0S  143.0E 4.0-5.4 AAAAA  Papua New Guinea           

 

Far-field seismic promotion from PNG also continued today. The strongest quakes outside PNG occurred as an M 5.2 and 5.3 in the South Sandwich Islands at the third node (120 degrees) from PNG as did a felt earthquake of M 4.0 in northern Italy. The strongest quake in the U.S. or Canada was an M 4.0 near Baffin Bay was near the region of concentrated surface energy from PNG (107-109 degrees). Other events near 103 degrees from PNG  were reported from Tanzania, East Africa (M 4.5). A moderate M 5.1 in Kamchatka was followed near local noon by an M 4.6. These quakes are located at the sixth node (60 degrees) from PNG and were probably promoted from that source.

 

O:  6MAR2018 07:34:50  55.3S   29.4W mb=5.3  EMSC   SOUTH SANDWICH ISLANDS REGION

P:  2MAR2018 115055    60.0S   29.0W 4.0-6.2 BCAAA  So. Sandwich Islands       

 

O:  6MAR2018 11:23:36  56.0S   28.3W mb=5.2  EMSC   SOUTH SANDWICH ISLANDS REGION

P:  6MAR2018 115055    58.0S   25.0W 4.0-5.8 ABBAA  So. Sandwich Islands       

 

O:  6MAR2018 00:41:45  52.4N  160.1E mb=4.6  EMSC   OFF EAST COAST OF KAMCHATKA  

O:  5MAR2018 15:42:43  52.6N  160.5E Mw=5.1  EMSC   OFF EAST COAST OF KAMCHATKA  

P:  6MAR2018 114977    52.0N  159.0E 4.0-5.9 AAAAA  Kamchatka                  

 

O:  5MAR2018 22:16:57   6.7S   35.4E mb=4.5  EMSC   TANZANIA                     

P:  2MAR2018 114823     6.0S   36.0E 4.0-5.5 BAAAA  Indian Ocean               

 

An M 3.3 hit the region south of San Francisco, California today. NEIC reported it was felt with intensity II-III in Gilroy, San Martin, Morgan Hill, Hollister, Aptos, Santa Cruz, Scotts Valley, San Jose, Santa Clara, Sunnyvale, Freemont, San Mateo, Oakland, Alameda, Berkeley and in general within about 100 km of the epicenter.  An aftershock of M 2.6 was lightly felt in Gilroy and Hollister, California with intensity II. The M 3.3 is the strongest earthquake within about 50 km of Gilroy, California since an M 3.6 on January 24, 2018 and prior to that an M 3.3 on December 24, 2017. A moderate earthquake is possible in this area in the near-term. Forecast 114886 expected this activity was likely around March 4.

 

O:  6MAR2018 12:44:06  37.0N  121.5W MD=2.6  EMSC   NORTHERN CALIFORNIA          

O:  6MAR2018 12:38:16  37.0N  121.5W Mw=3.3  EMSC   NORTHERN CALIFORNIA          

P:  4MAR2018 114886    37.4N  121.8W 2.5-4.8 AAAAA  Central California         

 

The strongest earthquake in the U.S. or Canada today was an M 4.0 in the Baffin Bay area near Pond Inlet, Canada. It was preceded by an M 2.5 foreshock to the southwest. Neither event was reported felt in this region. The last earthquake of M>=4.0 within about 200 km of this epicenter as reported by NEIC was an M 4.6 on May 22, 2017 and before that as an M 4.5 on August 26, 2016.  Forecast 114754 had expected today's quake of M 4.0 within about 50 km of this epicenter in early March. This may be a reaction to the nor'easter which hit the area several days ago. A very strong nor'easter is again expected around March 7-8 and could promote regional seismicity in the northeastern North American plate as well as moderate activity on the western boundaries of the North American plate. These earthquakes are at 105-109 degrees from the earthquakes in PNG and were likely promoted by strong energy concentration from those events at this distance.

 

O:  5MAR2018 12:07:48  73.9N   72.5W ML=4.0  NRCA  223 km NE from Pond Inlet     

P:  1MAR2018 114754    73.3N   73.5W 2.5-3.9 BAAAA  Baffin/Davis Strait Canada 

 

O:  5MAR2018 09:18:22  71.7N   75.8W ML=2.5  NRCA  136 km SE from Pond Inlet     

P:  4MAR2018 115002    71.0N   75.0W 2.5-4.2 AAAAA  Baffin/Davis Strait Canada 

 

OKLAHOMA RESPONDS TO FULL MOON

 

EARTHQUAKE SUMMARY FOR MARCH 4, 2018

 

The strongest earthquakes of the day continued in the aftershock sequence in  Papua New Guinea following the M 7.6 there on February 25. Earthquakes of M 5.8 and 6.0  were reported felt in the area today with intensity VI in Mendi, Southern Highlands, III in Porgera, Enga and III in Kiunga, Fly River, PNG.

Forecast 114833 had expected this activity around March 3.

 

O:  4MAR2018 14:33:20   6.0S  142.8E mb=5.6  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  4MAR2018 12:39:59   6.2S  142.7E mb=5.2  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  4MAR2018 11:44:23   6.2S  143.2E Mw=5.1  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  5MAR2018 00:27:46   6.3S  142.3E mb=4.1  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  4MAR2018 19:56:18   6.3S  142.6E mb=5.7  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  4MAR2018 22:38:01   6.4S  143.0E mb=4.2  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

O:  4MAR2018 20:24:03   6.5S  142.7E mb=4.9  EMSC   NEW GUINEA, PAPUA NEW GUINEA 

P:  3MAR2018 114833     6.0S  142.0E 4.0-6.5 AAAAA  Papua New Guinea           

 

The strongest earthquakes in the world outside PNG occurred today in the southern Kuril Islands. The largest of these was an M 5.4 which was not felt in this remote region. Forecasts 114959 and 114936 had expected this activity was likely in early March within about 25-100 km of these epicenters. The last earthquake in the southern Kuril Islands within about 150 km of these epicenters occurred on November 29, 2017 with M 5.4 and prior to that on June 28, 2017 (M 5.5). The last earthquake within the area with significantly larger magnitude than M 5.4 was an M 5.8 on October 23, 2016. Today's activity is located at the fifth node from the PNG earthquakes (51 degrees) and was probably promoted from that source. This area may also have been promoted by the full moon tidal stresses as noted in that forecast:

 

 

"The full moon arrived on March 2 at 00:51 UT. Longitudes which were sub-lunar at this time are near 13 West longitude and include areas of the Atlantic and Western Europe. Those which were sub-solar are near 167E and include portions of the Kamchatka/Komandorsky to Japan region and from New Guinea to Vanuatu and New Zealand. These are regions most likely to see tidal triggering, but this tidal promotion is not limited to these areas and can occur in many areas which see vertical tectonics or seismicity related to fluid flows." (February 27-March 3, 2018)

 

O:  4MAR2018 19:52:51  45.1N  147.8E Mw=5.4  EMSC   KURIL ISLANDS                 

P:  9MAR2018 114959    45.0N  148.0E 3.5-5.6 BAAAA  So. Kurils                 

 

O:  4MAR2018 23:04:19  43.8N  147.1E mb=4.0  EMSC   KURIL ISLANDS                

P:  8MAR2018 114936    44.0N  148.0E 3.5-5.4 BAAAA  Hokkaido, Japan            

 

A series of earthquakes in Oklahoma today included two of M 4.2 which were widely felt in the region. NEIC reported maximum intensity VI at Hunter and Fairmont, Oklahoma with V in Fairmont, Garber, Covington, Douglas, Jet, IV in Waukomis, Perry, Kremlin, Enid, Carrier, Douglas, Medford, and II as far as about 200 km from the epicenters. Unsubstantiated reports of felt effects came from as far as Kentucky, Minnesota, Nebraska and Missouri. As noted in previous summaries, larger earthquakes in this region commonly  occur near times of full and new moons. Pore pressure is increased at this time due to movements of water with high tidal stresses. This may be the cause of these increased magnitudes. These were the strongest earthquakes in the U.S. or Canada today. The area of Oklahoma has been quiet at the M 4.2 level and above for some time. The last such events in the region were widely felt on December 5, 2017 (M 4.2). Five events of M 4.2-4.3 occurred since November, 2016 in Oklahoma. At the time of the last such event in Oklahoma this summary noted the relation to the full moon as:

 

"The strongest earthquake in the U.S. or Canada outside Alaska today was an M 4.2 in Oklahoma. NEIC reported it was felt with maximum intensity IV in Oklahoma at Morrison, Perry, Pawnee, Tulsa, Oklahoma City, and in most areas of Oklahoma and Kansas within about 250 km of the epicenter. It was reported felt as far as Missouri and Nebraska. Other quakes in Oklahoma today included an M 2.8 felt lightly in Stillwater;  The M 4.2 occurred within near local solar midnight and was probably promoted by stresses and fluid motions associated with the full moon which maximize around this time. This summary has long held the position that much of the activity in the central Plain States of the U.S. is promoted tidally." (December 5, 2017)

 

Forecast 114921 had expected today's activity within about 50 km was likely around March 3.

 

O:  4MAR2018 23:17:17  36.5N   97.7W Mw=4.2  EMSC   OKLAHOMA                     

O:  5MAR2018 03:40:58  36.5N   97.7W Mw=4.2  EMSC   OKLAHOMA                     

O:  5MAR2018 06:35:19  36.5N   97.8W mb=2.7  EMSC   OKLAHOMA                     

O:  5MAR2018 03:12:08  37.0N   97.7W mb=2.3  EMSC   OKLAHOMA                     

P:  3MAR2018 114921    37.0N   98.0W 2.0-4.0 AAAAA  Southern Plains            

PROMOTED SEISMICITY AT 103 DEGREES FROM PNG CONTINUES

 

EARTHQUAKE SUMMARY FOR MARCH 3, 2018

 

Unusual seismicity continued today at 103 degrees from the M 7.6 in Papua New Guinea of February 25. In addition to moderate earthquakes in Nevada, the Rocky Mountains, southern California other activity at this distance occurred in Tanzania and in eastern Turkey today. Seismic energy reflects and refracts off the core-mantle boundary and returns to the surface at this distance, often helping to promote zonal seismicity in regions which are seismic. It is likely that several large earthquakes will occur at this distance from PNG in the next month, as this is often the case following major events such as that.

 

Some seismicity returned to the San Francisco Bay area today after a lull in activity following the M 7.6 in Papua New Guinea. Today's event of M 2.8 was widely felt in the area with intensity II-III reported by NEIC at Oakland, Berkeley, Emeryville, Orinda, Albany, Alameda, El Cerrito, Moraga, Lafayette, Richmond, El Sobrante, San Francisco, Martinez, Walnut Creek, San Pablo, Pleasant Hill, Concord, Danville, Vallejo, Larkspur, Breenbrae, San Bruon, American Canyon, and Fairfield and in general within about 50 km of the epicenter. This is not at the epicenter of the swarm which hit the area late in February but to the northwest of those epicenters. This is within about 15 km of the M 4.4 which occurred on January 4 and near the M 2.8 on December 25, 2017 and the M 3.0 of June 21, 2017. Forecast 114639 expected today's event within this region was likely around February 28.

 

O:  3MAR2018 11:04:04  37.9N  122.2W MD=2.8  EMSC   SAN FRANCISCO BAY AREA, CALIF.

P:  2MAR2018 114886    37.7N  121.9W 2.5-4.5 AAAAA  Central California         

P: 28FEB2018 114639    38.0N  122.3W 2.5-4.6 BAAAA  Central California         

 

An M 2.7 also continued promoted activity in the Anza area of southern California today. This event was reported by NEIC to have been felt with intensity II in Palm Desert, San Diego, Riverside and Chula Vista, California. This is part of the activation of southern California at 103 degrees from PNG in late February. Forecast 114670 had expected this activity within about 25 km of the epicenter was likely in early March.

 

O:  4MAR2018 09:25:08  33.5N  116.5W ML=2.0  EMSC   SOUTHERN CALIFORNIA          

O:  3MAR2018 10:08:22  33.5N  116.5W ML=2.2  EMSC   SOUTHERN CALIFORNIA          

O:  3MAR2018 07:00:12  33.5N  116.5W ML=2.6  EMSC   SOUTHERN CALIFORNIA          

P:  1MAR2018 114670    33.4N  116.7W 2.5-4.5 AAAAA  So. California             

 

An earthquake of M 4.2 also occurred at 103 degrees from the New Guinea events today in the region of eastern Turkey. This follows an M 4.9 in Tanzania earlier at the same distance from PNG. EMSC reported this earthquake was felt with moderate to light intensity in Turkey at Otlukbeli, Tercan, Erzincan, Pulumur, Batumi and Yenisehir. This is not an aseismic area but it has been some time since activity reached this magnitude in the region - the last being an M 5.1 on May 11, 2017 and an M 4.4 on December 16, 2016. Forecast 114685 had expected a moderate quake in this area was likely around February 25 within about 100 km of today's event. More and larger seismic events may follow in this region in the next days.

 

O:  3MAR2018 09:05:49  40.0N   40.0E mb=4.2  EMSC   EASTERN TURKEY               

P: 25FEB2018 114685    39.0N   40.0E 3.5-5.2 CAAAA  Turkey                     

 

The strongest earthquakes in the U.S. or Canada today were a M 4.9 and 4.5 in the Fox Islands, Aleutians. They were not reported felt in this remote area. The Fox Islands can see large earthquakes, especially in late winter or early Spring when meteorological storms in the area promote seismicity. During the past six months two earthquakes of M>4.9 have hit the Fox Islands - on January 28, 2018 (M 5.1) and on December 10, 2017 (M 5.0). Forecast 114971 had expected today's activity within about 50 km of these epicenter was likely in early March. This activity in the Fox Islands is at the fifth node (72 degrees) from Papua New Guinea as was probably promoted from that source.

  

O:  3MAR2018 07:11:24  52.0N  169.3W mb=4.5  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

O:  4MAR2018 08:16:28  52.5N  170.6W mb=4.9  EMSC   FOX ISLANDS, ALEUTIAN ISLANDS

P:  2MAR2018 114971    52.2N  171.1W 3.5-4.9 AAAAA  Andreanoff Isls, Aleutians 

 

An unusual earthquake of M 3.9 shook broad areas of Jamaica today.  NEIC reported this earthquake of M 3.9 in Jamaica was felt with intensity IV in Kingston, Saint Andrew, Jamaica and II-III in the area(s) of Jamaica at Buff Bay, Stony Hill, Constant Spring, Mona, HalfWay Tree, Portmore and Wakefield.  The last earthquake of M>=3.9 within about 200 km of this epicenter in Jamaica was an M 4.2 on May 6, 2011. Earthquakes to the north in Cuba have more recently occurred in April 2015 and November 2016 with M 3.9-4.5.

Forecast 114844 had expected this event to the west was likely around March 4.

 

O:  3MAR2018 18:53:25  18.2N   76.7W mb=3.9  EMSC   JAMAICA REGION               

P:  4MAR2018 114844    19.0N   81.0W 3.5-5.7 AACAA  Caribbean Sea              

 

 

 

DISPERSED SEISMICITY SHOWS FAR-FIELD AND TIDAL PROMOTION

 

EARTHQUAKE SUMMARY FOR MARCH 2, 2018

 

It was a relatively quiet day in global seismicity today. The earthquakes of M>=5 tended to occur near the International Date Line (IDL) - in the Kermadec Islands, the Rat Islands and the Loyalty Islands - and in the region of Indonesia including more events in the Sumatra swarm and aftershocks in New Guinea. Other unusual quakes occurred 180 degrees from the IDL near the Greenwich Meridian. These included light to moderate earthquakes in Spain, the Azores and Tanzania.  Moderate aftershocks in eastern New Guinea continued to be felt today. Many of these were felt with intensity II-III in Porgera, Enga, Mendi and Kiunga, Fly River, New Guinea. Far-field seismicity at 103 degrees from New Guinea today included an M 4.7-4.9 in Tanzania, Africa. This is the pattern expected in this summary as related to the full moon of March 2:

 

 

"The full moon arrived on March 2 at 00:51 UT. Longitudes which were sub-lunar at this time are near 13 West longitude and include areas of the Atlantic and Western Europe. Those which were sub-solar are near 167E and include portions of the Kamchatka/Komandorsky to Japan region and from New Guinea to Vanuatu and New Zealand. These are regions most likely to see tidal triggering, but this tidal promotion is not limited to these area and can occur in many areas which see vertical tectonics or seismicity related to fluid flows." (February 27-March 2, 2018)

 

An unusual earthquake of M 4.7 occurred today in Tanzania. NEIC reported it was felt with intensity II in Morogoro, Tanzania. This epicenter is located at 103 degrees from the M 7.6 in Papua New Guinea of February 25, 2018. It is likely that energy concentrated at this distance on the surface of the earth after reflection and refraction off core-mantle boundaries helped promote this event in Tanzania. Earthquakes of similar magnitude within about 250 km of this epicenter have most recently occurred on March 19, 2017 (M 4.8) and September

8, 2015 (M 4.8). The last of M>=5 was an M 5.2 on August 3, 2010. Forecast 114823 had expected today's event was likely around March 2. Tropical Cyclone Dumazile to the southeast of this may by promoting regional activity such as this  in Tanzania and in the South Indian Ocean (M 4.9) at this time.

 

"Tropical cyclone Dumazile formed today west of northern Madagascar with winds up toe 50 kts.  It is expected to track to the south along the east coast of Madagascar over the next five days passing west of La Reunion on March 5-6. This is an aseismic region but stresses from Dumazile may have helped trigger the M 4.8 in Tanzania today. As this storm moves to the south it may reach an area antipodal to southern California around March 8. This could help promote moderate seismicity in southern California around this time." (March 3, 2018)

 

 

O:  3MAR2018 04:40:08   7.7S   38.2E mb=4.7  EMSC   TANZANIA                     

P:  2MAR2018 114823     6.0S   36.0E 4.0-5.5 ABBAA  Indian Ocean               

 

O:  2MAR2018 21:29:39  16.6S   67.3E ML=4.9  EMSC   MID-INDIAN RIDGE             

P:  1MAR2018 114762    17.0S   67.0E 4.0-5.4 AAAAA  So. Indian Ocean           

 

An unusually large M 4.1 event also occurred in the area of Spain today. EMSC reported it was felt with moderate intensity in Spain at Campos del Rio, Mula, Blanca, Murcia, and Rojales. The last earthquake within about 100 km of this epicenter with M>=4.1 was an 4.4 on January 31, 2012. A moderate M 5.1 hite the region on May 11, 2011 after a six-year absence of such regional activity. Forecast 114650 had expected today's earthquake was likely within about 50 km of the epicenter around February 27. An earthquake of M 4.3 in the Azores was also felt lightly today.

 

O:  2MAR2018 19:16:12  38.0N    1.4W ML=3.3  EMSC   SPAIN                        

O:  2MAR2018 19:08:22  38.0N    1.4W ML=4.1  EMSC   SPAIN                        

P: 27FEB2018 114650    38.0N    2.0W 3.5-5.1 BAAAA  Morocco/Spain              

 

O:  2MAR2018 19:39:46  38.3N   25.8W ML=4.3  EMSC   AZORES ISLANDS, PORTUGAL     

 

The largest earthquake in the U.S. or Canada today was an M 5.1 in the Rat Islands, Aleutians and had been anticipated as a tidally promoted event at this time. Two earthquakes of M 5.1-5.2 have hit the Rat Islands in the past five months - on January 13 and February 9, 2018. These may be aftershocks of an M 6.6 event of October 8, 2017. Today's event was not reported felt in this remote area. Forecast 114984 had expected this activity in the Rat Islands around March 4. The Aleutians often show a significant increase in seismicity in early March, probably associated with regional storms. This may occur under the current circumstances as well. 

 

O:  2MAR2018 21:44:53  51.8N  178.7E mb=5.1  EMSC   RAT ISLANDS, ALEUTIAN ISLANDS

P:  3MAR2018 114984    52.0N  176.0E 4.0-5.8 AABAA  Rat Islands                

P:  4MAR2018 114984    50.0N  178.0E 4.0-5.7 ABAAA  Rat Islands                

 

 

An earthquake of M 4.6 occurred directly south of the Rat Islands in the area south of the Kermadec Islands as well today. This was probably promoted by tidal stresses. Forecast 115045 had expected this event within about 100 km of the epicenter in early March.

 

O:  2MAR2018 14:19:58  32.2S  179.9E mb=4.6  EMSC   SOUTH OF KERMADEC ISLANDS    

P:  6MAR2018 115045    31.0S  180.0W 4.0-5.4 BAAAA  So. Kermadec Islands       

 

The series of earthquakes in the region of Sumatra also continued today. The

largest quake in the world today was in this series - an M 5.2 southwest of Sumatra. Other felt earthquakes in the area of northern Sumatra occurred at different epicenters with M 4.5, 3.9, 4.7 and 4.7.

 

O:  2MAR2018 21:03:42   0.2S   96.7E Mw=5.2  EMSC   SOUTHWEST OF SUMATRA, INDONESI

P:  1MAR2018 114564     0.0N   97.0E 4.0-5.6 AAAAA  Nicobar Islands            

 

O:  2MAR2018 08:21:10   1.8N   98.9E mb=4.5  EMSC   NORTHERN SUMATRA, INDONESIA  

O:  3MAR2018 02:48:25   1.9N   98.9E ML=3.9  EMSC   NORTHERN SUMATRA, INDONESIA  

O: 03MAR2018 02:48:25  01.9N  098.9E MS=3.9  BMG  Felt with intensity II-III

P:  7MAR2018 114812     1.0N   97.0E 4.0-5.7 BABAA  Nicobar Islands            

 

BMG reported the M 3.9 was felt with intensity II-III in Tarutung, Sumatra, Indonesia.

 

 

O:  2MAR2018 09:13:44   3.5N   97.9E mb=4.7  EMSC   NORTHERN SUMATRA, INDONESIA   

O: 02MAR2018 09:13:45  03.4N  097.8E MS=4.4  BMG  Felt with intensity II-III

P:  2MAR2018 114813     2.0N   96.0E 4.0-5.8 ABBAA  Nicobar Islands            

 

BMG reported this earthquake was felt with intensity II-III in Aceh Tenggara, Aceh, Sumatra, Indonesia.

 

O:  2MAR2018 12:19:29   4.8N   94.3E mb=4.7  EMSC   FF W COAST OF NORTHERN SUMATRA

O: 02MAR2018 12:19:37  04.5N  094.8E MS=4.3  BMG  Felt with intensity II

P:  6MAR2018 114813     4.0N   94.0E 4.0-5.5 BAAAA  Nicobar Islands            

 

BMG reported this earthquake was felt with intensity II in Banda Aceh,  Sumatra, Indonesia.