SEISMICITY STRONG NEAR INTERNATIONAL DATE LINE

 

EARTHQUAKE SUMMARY FOR JULY 23, 2016

 

Strong solar flares today apparently helped trigger seismicity near the International Date Line (IDL) at 180 East longitude today. Three high class solar flares occurred with M5.0, M5.5 and M7.6.  The strongest solar flare in more than a year occurred early on July 23. SWPC recorded it with class M7.6. The last flare of higher class was an M7.9 on June 25, 2015. In the previous summary it was noted:

 

"Strong M5.0 and M5.5 flares occurred early on July 23. These could help trigger immediate seismicity in areas of the Tonga/Fiji/Vanuatu region or in the Aleutians or in western South America, Mexico, Oklahoma or in central Asia. Additional seismicity will probably be promoted at the end of July in these and areas near the geomagnetic equator. A seismic watch is currently in effect for these regions." (July 22-23, 2016)

 

In addition to the M 4.3 in Hawaii early in the day, reported in the previous issue of this summary, moderate earthquakes also occurred today in the Alaska Peninsula (M 5.2-5.5), the Andreanof Islands, Aleutians (M 4.4); Samoa (M 5.6) and as a series in Tonga/Fiji (M 4.5-5.3). The strongest earthquake in North America outside Alaska was an M 5.4 south of Michoacan and Jalisco, Mexico.

 

The strongest earthquake in the world today occurred near Samoa with M 5.7-5.8. NEIC reported it was felt with intensity II-III throughout the region including at Paepaeala, Faleu, Upolu, Siusega, Talimatau, Tulaele, Apia, Samoa and American Samoa. The last earthquake of M>=5.8 within about 150 km of this epicenter occurred on July 10, 2016 (M 6.0, 5.8). Today's event is probably an aftershock of those earthquakes. The last event of significantly larger magnitude in the area was an M 6.5 on March 30, 2015. Forecast 99758 expected today's quake was likely within this area around July 18.

 

O: 23JUL2016 20:09:17  15.3S  173.6W mb=5.8  EMSC   TONGA                        

P: 18JUL2016 99758     16.0S  173.0W 4.0-6.1 BAAAA  Tonga Islands              

 

The quake in Samoa was accompanied by a series of moderate quakes in Tonga and

Fiji. The strongest of these was an M 5.2 in the area south of Fiji. This event occurred within about half an hour of local solar midnight and was probably promoted by solar flare activity.

 

O: 23JUL2016 21:45:25  23.5S  175.5W mb=4.9  EMSC   TONGA REGION                 

O: 23JUL2016 14:24:21  20.9S  178.7W mb=4.7  EMSC   FIJI REGION                  

O: 23JUL2016 12:38:47  24.2S  179.6W mb=5.2  EMSC   SOUTH OF FIJI ISLANDS        

P: 15JUL2016 99772     23.0S  177.0W 4.0-5.6 CBBAA  Tonga Islands              

 

The strongest earthquake in the U.S. or Canada today was N 5.2-5.5 in the Alaska Peninsula.  NEIC reported this earthquake of M 5.2 in the Alaska Peninsula was felt with intensity II-III in the area(s) of Homer, Cooper Landing, Seward, Eagle River and Kodiak, Alaska. This earthquake occurred within about 30 minutes of local solar midnight, a prime time for SFE and Tidal triggering and was likely promoted by the series of strong solar flares which preceded it. The last earthquake of M>=5.2 within about 200 km of this epicenter occurred on June 13, 2010 with M 5.4. The last of M>5.5 was an M 6.8 on July 28, 2001. Forecast 99960 had expected a moderate earthquake in this area was likely around July 23.

 

O: 23JUL2016 09:59:01  58.5N  156.5W ml=5.2  ANSS   20km SSE of King Cove, Alaska

O: 23JUL2016 09:59:02  58.8N  156.6W Mw=5.5  EMSC   ALASKA PENINSULA             

P: 23JUL2016 99960     56.8N  156.7W 3.5-5.4 ABAAA  Alaska Peninsula           

 

An earthquake of M 4.4 also hit at 173 West longitude in the Andreanof Islands today. It was not reported felt in this remote epicentral area. This is the  first event of M>=4.4 in the eastern Andreanof Islands within about 150 km  of this epicenter since an M 4.4 on May 30, 2016. A strong earthquake about 150 km to the west occurred as an M 6.0-6.2 on March 19, 2016 after a series of foreshocks. Forecast 99963 had expected today's earthquake was likely within  about 40 km of the epicenter around July 27.

 

O: 23JUL2016 14:13:48  51.8N  172.9W Ml=4.4  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P: 27JUL2016 99963     52.1N  172.8W 3.5-4.9 BAAAA  Andreanoff Isls, Aleutians 

 

The M 5.3-5.4 earthquake south of Mexico in the region south of Jalisco appears to have been promoted by Tropical Storm Frank which passed over this epicenter two days ago. In the previous issue of this summary it had been noted in this regard:

 

"TS    FRANK    2016-07-22  00:00 UT  16.4N  105.9W  055 kts  South of Jalisco, Mexico   

 

TS Frank (TD 07E) formed today south of Jalisco, Mexico with winds up to 70 kts. It is expected to track to the northwest over the next week and not to encounter land. This is the latest in a series of similar storms which have hit the region over the past month. It is relatively close to the Mexican coast and could have moderate effects on seismicity in western Mexico but a strong earthquake in the area is not expected at this time." (July 22-23, 2016)

 

Note that TS Frank would have formed the day before this report near 15N 104W directly over the epicenter of today's earthquake - another likely case for weather-related seismicity. Forecast 99585 had expected this event was likely within about 50 km of this epicenter around July 19. SFE promotion of this earthquake is also likely. The last earthquake of M>=5.4 within about 150 km  of this epicenter occurred as an M 5.5 on January 22, 2011. The only other such event in the area in the past 25 years was an M 5.9 on October 28, 1994. A moderate earthquake of M5.5-5.7 also hit southern Alaska on January 22, 2011 suggesting a possible relation between the two events (as with today's).

 

O: 23JUL2016 08:52:00  14.8N  103.7W mb=5.4  EMSC   OFF COAST OF GUERRERO, MEXICO

O: 23JUL2016 08:52:01  14.8N  103.6W mb=5.4  ANSS   coast of Guerrero Mexico

P: 19JUL2016 99585     15.0N  104.0W 3.5-5.6 BAAAA  Michoacan, Mexico          

 

Somewhat surprisingly after a series of unusually large earthquakes, California fell quiet today. The only event of M>=2 recorded in the state was an M 3.1 in Central California in the continuing swarm near Ridgemark south of San Francisco. This event had been expected within about 25 km to occur around July 23. No damages of casualties were reported with today's earthquake.

 

NEIC reported this earthquake of M 3.1 in Central California was felt with intensity II-III in the area(s) of Soledad, California and possibly as far as Berkeley, California.

 

O: 23JUL2016 23:24:01  36.6N  121.3W ML=3.1  EMSC   CENTRAL CALIFORNIA           

P: 23JUL2016 99878     36.8N  121.3W 2.5-4.4 AAAAA  Central California         

OTHER GLOBAL EARTHQUAKE ACTIVITY

 

For most events there are two listings. The first line is the observed event starting with "O:" for Observed. There follows the date, month and year, the time in UT hours:minutes:seconds, the latitude and longitude, the given magnitude and the reporting agency followed by the geographic location. The second line starts with "P:" This is the forecast event as forecast in our summaries normally more than a month in advance. Magnitudes may vary in response to updated seismic watches and daily variations due to tidal and other influences. This line has the forecast date, month and year, the forecast number, latitude, longitude and forecast magnitude range.  This is followed by a comparison between the forecast and the event. The comparison includes letters A-D. The first is number of days difference from predicted (A:up to 2, B3-5; C:6-10; D:more than 10), Difference in latitude (A:up to 1 degree; B:1-2 degrees; C:2-4 degrees; D:more than 4 degrees); longitude (same comparison as with latitude); magnitude (A: within forecast range; B: higher than forecast range; C: lower than forecast range; D: no comparison possible). The last letter is a stand in for a future comparison which needs to be done statistically after a large number of forecasts have been made. In previous data, an excellent match is generally AAAAA; a good match as one or two B's; a fair match has several B's and C's and a poor match is one which contains a number of C's or D's. 

 

ASIA

 

O: 24JUL2016 05:49:39  34.8N   57.3E ML=4.2  EMSC   NORTHEASTERN IRAN            

P: 21JUL2016 99635     37.0N   59.0E 3.8-5.3 BCBAA  No. Iran                   

 

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

 

INDONESIA AND PHILIPPINES

 

O: 23JUL2016 21:30:07   1.2N  126.9E mb=4.8  EMSC   MOLUCCA SEA                  

O: 23JUL2016 21:30:06  01.1N  126.8E SR=4.6  BMG  Felt with intensity III-IV in Alor and II in Ternate, Halmahera, Indonesia.

P: 29JUL2016 99797      1.0N  128.0E 4.0-5.4 CAAAA  Halmahera                  

 

BMG reported this earthquake was felt with intensity III-IV in Alor and II in Ternate, Halmahera, Indonesia.

 

O: 23JUL2016 23:05:45   5.5S  147.1E mb=4.7  EMSC   EASTERN NEW GUINEA REG., P.N.G

P: 28JUL2016 99810      5.0S  148.0E 4.0-5.9 BAAAA  New Ireland                

 

NEIC reported this earthquake of M 4.6 northeast of New Guinea  was felt with intensity II-III in the area(s) of Law, Morobe, Papua New Guinea.

 

O: 24JUL2016 05:39:51   6.5S  147.6E mb=4.5  EMSC   EASTERN NEW GUINEA REG., P.N.G

P: 28JUL2016 99810      5.0S  148.0E 4.0-5.9 BBAAA  New Ireland                

 

O: 23JUL2016 16:35:47   8.4S  124.3E mb=4.6  EMSC   KEPULAUAN ALOR, INDONESIA    

O: 23JUL2016 16:35:46  08.5S  124.2E SR=4.6  BMG  Felt in the epicentral area of Indonesia.

P: 24JUL2016 99803      7.0S  125.0E 4.0-5.4 ABAAA  Banda Sea                  

 

BMG reported this earthquake was felt in the epicentral area of Indonesia.

 

O: 23JUL2016 21:23:52  10.1N  122.9E mb=4.4  EMSC   PANAY, PHILIPPINES           

P: 19JUL2016 99583     11.0N  125.0E 3.5-5.0 BABAA  Luzon, Philippines         

 

O: 24JUL2016 04:22:20  12.0N  121.7E mb=4.5  EMSC   PANAY, PHILIPPINES           

O: 24JUL2016 04:22:16  11.9N  121.5E MS=4.5  PHI  Felt with intensity IV in Ca;uya and Pandan, Antique; III in Libertad, Antique; Boracay, Aklan; Bulalacao and Magsaysay, Oriental Mindoro; Odiopngan, Romblon and II in Buruanga and Culasi, Antique; Nabas and Malay, Aklan; San Jose, Romblon, Indonesia.

P: 31JUL2016 99839     12.0N  121.0E 3.5-4.9 CAAAA  Luzon, Philippines         

 

NEIC reported this earthquake of M 4.5 in Central Philippines was felt with intensity II-III in the area(s) of Balabag, Western Visayas, Philippines.

PHIVOLCS reported it was felt with intensity IV in Ca;uya and Pandan, Antique; III in Libertad, Antique; Boracay, Aklan; Bulalacao and Magsaysay, Oriental Mindoro; Odiopngan, Romblon and II in Buruanga and Culasi, Antique; Nabas and Malay, Aklan; San Jose, Romblon, Indonesia.

 

O: 24JUL2016 01:45:13  20.7N  121.4E mb=4.7  EMSC   BATAN ISL REGION, PHILIPPINES

P: 23JUL2016 99868     20.0N  122.0E 4.0-5.4 AAAAA  Taiwan                     

 

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

 

CENTRAL AND SOUTH AMERICA

 

O: 23JUL2016 18:37     16.8S   71.6W mb=3.8  IGP    NE of Punta de Bombon-Arequipa

P: 19JUL2016 99755     17.0S   70.0W 4.0-5.8 BABAA  So. Peru/Bolivia           

 

O: 23JUL2016 16:36     12.2S   77.4W mb=3.8  IGP    Calao, Lima, Peru            

P: 28JUL2016 99814      8.0S   78.0W 4.0-5.4 BCAAA  No. Peru                   

 

IGP reported this earthquake was felt with intensity II in Calao, Lima, Peru.

 

O: 23JUL2016 08:52:00  14.8N  103.7W mb=5.4  EMSC   OFF COAST OF GUERRERO, MEXICO

O: 23JUL2016 08:52:01  14.8N  103.6W mb=5.4  ANSS   coast of Guerrero Mexico

P: 19JUL2016 99585     15.0N  104.0W 3.5-5.6 BAAAA  Michoacan, Mexico          

 

O: 23JUL2016 07:53:03  18.6N   64.8W Md=3.0  EMSC   VIRGIN ISLANDS REGION        

P: 24JUL2016 99838     18.0N   64.0W 3.0-4.9 AAAAA  Leeward Islands            

 

O: 23JUL2016 21:47:45  18.8N   64.0W Md=3.7  EMSC   VIRGIN ISLANDS REGION        

O: 23JUL2016 14:00:11  19.4N   63.8W Md=3.1  EMSC   VIRGIN ISLANDS REGION        

P: 21JUL2016 99582     19.0N   64.0W 3.0-5.0 AAAAA  Leeward Islands            

 

O: 23JUL2016 15:09:43  19.4N   68.4W Md=3.4  EMSC   DOMINICAN REPUBLIC REGION    

P: 26JUL2016 99856     20.0N   68.0W 3.0-4.6 BAAAA  Bahamas/No. Caribbean      

 

O: 23JUL2016 22:17:56  22.4S   67.1W mb=5.0  EMSC   POTOSI, BOLIVIA              

P: 21JUL2016 99764     24.0S   66.0W 4.0-5.6 ABAAA  Argentina                  

 

AFRICA AND EUROPE

 

O: 23JUL2016 18:31:49  38.3N   20.3E mb=4.0  ANSS   NNW of Lixourion Greece      

P: 19JUL2016 99632     39.0N   21.0E 3.0-4.6 AAAAA  No. Greece                 

 

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

 

SOUTHWEST PACIFIC

 

O: 23JUL2016 18:21:51  10.9S  165.7E mb=5.2  EMSC   SANTA CRUZ ISLANDS           

P: 15JUL2016 99761     11.0S  165.0E 4.0-5.5 CAAAA  Vanuatu Islands            

 

O: 23JUL2016 20:09:17  15.3S  173.6W mb=5.8  EMSC   TONGA                        

P: 18JUL2016 99758     16.0S  173.0W 4.0-6.1 BAAAA  Tonga Islands              

 

O: 23JUL2016 21:45:25  23.5S  175.5W mb=4.9  EMSC   TONGA REGION                 

O: 23JUL2016 14:24:21  20.9S  178.7W mb=4.7  EMSC   FIJI REGION                  

O: 23JUL2016 12:38:47  24.2S  179.6W mb=5.2  EMSC   SOUTH OF FIJI ISLANDS        

P: 15JUL2016 99772     23.0S  177.0W 4.0-5.6 CBBAA  Tonga Islands              

 

OCEAN RIDGES

 

O: 23JUL2016 07:44:11  56.5S   26.8W mb=4.9  EMSC   SOUTH SANDWICH ISLANDS REGION

P: 18JUL2016 99790     59.0S   26.0W 4.0-5.8 BCAAA  So. Sandwich Islands       

 

No significant (M>=5) or unusual earthquakes were reported on Ocean Ridges today.

 

NEW ZEALAND AND AUSTRALIA REGION

 

No earthquakes of M>=4 were recorded in the regions of New Zealand or Australia

today. GeoNet did not report any felt events in the area.

 

JAPAN AND KURIL ISLANDS

 

O: 24JUL2016 00:51:01  35.6N  140.4E mb=4.5  EMSC   NEAR EAST COAST OF HONSHU, JAP

P: 24JUL2016 99902     35.0N  141.0E 4.0-5.6 AAAAA  Off East Coast Honshu      

 

NEIC reported this earthquake of M 4.5 in Southeastern Honshu, Japan was felt with intensity II-III in the area(s) of Tokyo and Komai and in Narashino, Chiba, Japan.

 

O: 24JUL2016 02:51:20  42.9N  143.1E mb=5.3  EMSC   HOKKAIDO, JAPAN REGION       

P: 25JUL2016 99929     42.0N  142.0E 3.5-5.4 AAAAA  Hokkaido, Japan            

 

NEIC reported this earthquake of M 5.3 in Hokkaido, Japan was felt with intensity II-III in the area(s) of Sapporo, Hokkaido and in Aomori at Misawa and Hachinohe, Japan.

 

O: 23JUL2016 07:43:29  46.3N  149.5E mb=4.1  EMSC   KURIL ISLANDS                

P: 21JUL2016 99671     44.0N  150.0E 3.5-5.6 ACAAA  Hokkaido, Japan            

 

U.S./CANADA*

 

WESTERN U.S./CANADA

 

CALIFORNIA

 

O: 23JUL2016 23:24:01  36.6N  121.3W ML=3.1  EMSC   CENTRAL CALIFORNIA           

P: 23JUL2016 99878     36.8N  121.3W 2.5-4.4 AAAAA  Central California         

 

ALASKA

 

O: 23JUL2016 14:13:48  51.8N  172.9W Ml=4.4  EMSC   ANDREANOF ISLANDS, ALEUTIAN IS

P: 27JUL2016 99963     52.1N  172.8W 3.5-4.9 BAAAA  Andreanoff Isls, Aleutians 

 

O: 23JUL2016 09:59:01  58.5N  156.5W ml=5.2  ANSS   20km SSE of King Cove, Alaska

O: 23JUL2016 09:59:02  58.8N  156.6W Mw=5.5  EMSC   ALASKA PENINSULA             

P: 23JUL2016 99960     56.8N  156.7W 3.5-5.4 ABAAA  Alaska Peninsula           

 

O: 24JUL2016 01:24:54  61.2N  149.6W Ml=3.2  EMSC   SOUTHERN ALASKA              

P: 24JUL2016 99985     61.1N  151.4W 3.2-5.1 AAAAA  Central Alaska             

 

NEIC reported this earthquake of M 3.2 in Southern Alaska was felt with intensity II-III in the area(s) of Anchorage, Alaska.

 

O: 23JUL2016 21:27:44  63.2N  152.5W Ml=3.1  EMSC   CENTRAL ALASKA               

P: 24JUL2016 99986     63.0N  151.5W 3.2-5.0 AAAAA  Central Alaska             

P: 24JUL2016 99988     63.0N  151.5W 3.2-5.0 AAAAA  Central Alaska             

 

O: 23JUL2016 19:43:00  66.3N  141.4W Ml=3.1  EMSC   NORTHERN ALASKA              

P: 22JUL2016 99991     65.0N  139.0W 3.0-4.6 ABAAA  Northern Alaska            

 

PACIFIC NORTHWESTERN U.S./WESTERN CANADA

 

No events of M>=2 were located in the northwestern U.S. or western Canada today.

 

ROCKY MOUNTAINS REGION

 

No earthquakes of M>=2 were located in the Rocky Mountain region today.

 

EASTERN U.S./CANADA

 

O: 24JUL2016 03:08:41  36.6N   98.6W mb=2.6  EMSC   OKLAHOMA                     

O: 24JUL2016 04:45:18  36.9N   98.8W mb=2.9  EMSC   OKLAHOMA                     

P: 25JUL2016 99914     36.0N   98.0W 2.0-4.2 AAAAA  Southern Plains            

 

O: 23JUL2016 15:35:02  36.4N   89.5W md=1.7  ANSS   NW of Tiptonville Tennessee  

P: 22JUL2016 99893     36.5N   89.6W 2.0-4.4 AAAAA  New Madrid area            

 

HAWAII

 

O: 23JUL2016 18:57:57  19.2N  155.7W ML=2.7  EMSC   ISLAND OF HAWAII, HAWAII     

O: 24JUL2016 00:48:27  19.4N  155.2W ML=2.7  EMSC   ISLAND OF HAWAII, HAWAII     

P: 24JUL2016 99836     18.8N  155.2W 3.0-4.4 AAAAA  Hawaii                     

 

NEIC reported these earthquakes of M 2.7 in Hawaii were felt with intensity II-III in the area(s) of Naalehu and Pahoa, Hawaii.

 

No earthquakes of M>=3 were located in Hawaii.