- Earthquake summary

MODERATE SWARM OFF NORTHERN CALIFORNIA

EARTHQUAKE SUMMARY FOR OCTOBER 17, 2017

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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: 17OCT2017 20:16:11 33.0N 91.5E mb=4.3 EMSC EASTERN XIZANG

P: 16OCT2017 111336 33.0N 92.0E 3.8-5.4 AAAAA Xizang

O: 17OCT2017 18:52:36 37.8N 57.3E mb=4.7 EMSC NORTHEASTERN IRAN

P: 17OCT2017 111310 37.0N 59.0E 3.8-5.2 AABAA No. Iran

O: 17OCT2017 16:54:09 49.2N 147.8E mb=4.6 EMSC SEA OF OKHOTSK

P: 15OCT2017 111344 44.0N 148.0E 3.5-5.6 ACAAA Hokkaido, Japan

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

INDONESIA AND PHILIPPINES

O: 17OCT2017 13:30:37 3.9N 95.8E mb=4.6 EMSC FF W COAST OF NORTHERN SUMATRA

P: 16OCT2017 111222 5.0N 94.0E 4.0-5.6 ABBAA Nicobar Islands

O: 18OCT2017 00:46:29 6.1N 123.8E mb=4.7 EMSC MORO GULF, MINDANAO, PHILIPPIN

P: 20OCT2017 111215 7.0N 124.0E 4.0-5.4 AAAAA Central Philippines

O: 18OCT2017 00:22:15 9.8S 114.2E mb=4.4 EMSC SOUTH OF BALI, INDONESIA

P: 21OCT2017 111236 9.0S 114.0E 4.0-5.4 BAAAA So. of Bali

CENTRAL AND SOUTH AMERICA

O: 17OCT2017 09:06:30 9.3N 84.5W ML=4.1 EMSC COSTA RICA

P: 16OCT2017 111217 9.0N 84.0W 3.5-5.3 AAAAA Costa Rica

O: 17OCT2017 23:03:42 12.8N 87.7W mb=4.8 EMSC NEAR COAST OF NICARAGUA

P: 19OCT2017 111264 12.0N 88.0W 3.5-5.1 AAAAA Nicaragua

NEIC reported this earthquake of M 4.8 in Nicaragua was felt with intensity II-III in the area(s) of Nicaragua at San Francisco and Managua and in Antiguo Cuscatlan, El Salvador.

O: 17OCT2017 13:39:03 15.7S 70.7W mb=4.4 EMSC SOUTHERN PERU

P: 17OCT2017 111425 16.0S 73.0W 4.0-6.0 AABAA So. Peru/Bolivia

O: 17OCT2017 04:25:55 14.7N 93.3W ML=4.1 UNAM l SUROESTE de MAPASTEPEC, CHIS *:

O: 17OCT2017 10:13:48 14.1N 93.4W ML=4.2 UNAM al SUROESTE de CD HIDALGO, CHIS *:

O: 17OCT2017 10:13:48 14.1N 93.4W ML=4.2 EMSC OFF COAST OF CHIAPAS, MEXICO

P: 14OCT2017 111250 16.0N 93.0W 3.5-5.6 AAAAA Chiapas, Mexico

P: 18OCT2017 111249 15.0N 95.0W 3.5-5.3 AAAAA Chiapas, Mexico

O: 17OCT2017 18:33:13 17.0N 94.9W ML=4.2 EMSC OAXACA, MEXICO

P: 20OCT2017 111250 18.0N 95.0W 3.5-5.3 BAAAA Chiapas, Mexico

O: 17OCT2017 11:58:28 22.7S 67.6W Mw=4.8 EMSC POTOSI, BOLIVIA

O: 17OCT2017 17:43:19 24.1S 67.1W mb=4.1 EMSC SALTA, ARGENTINA

P: 20OCT2017 111434 24.0S 69.0W 4.0-5.8 BAAAA Coast No. Chile

O: 17OCT2017 10:40:41 32.6S 71.1W mb=4.1 EMSC VALPARAISO, CHILE

P: 20OCT2017 111446 33.0S 70.0W 4.0-5.8 BAAAA Central Chile

NEIC reported this earthquake of M 4.1 in Central Chile was felt with maximum intensity IV in Valparaiso at Calera, Quillota, Vina del Mar, Cabildo, and intensity II-III in the area(s) of San Felipe, Quilpue, and Valparaiso, Chile.

O: 17OCT2017 04:25:55 14.7N 93.3W ML=4.1 UNAM l SUROESTE de MAPASTEPEC, CHIS *:

O: 17OCT2017 10:13:48 14.1N 93.4W ML=4.2 UNAM al SUROESTE de CD HIDALGO, CHIS *:

O: 17OCT2017 08:06:39 15.0N 94.3W ML=4.0 UNAM al SUROESTE de TONALA, CHIS *: 15.

O: 17OCT2017 23:23:51 15.0N 94.4W ML=4.4 UNAM al SUROESTE de TONALA, CHIS *: 15.

O: 17OCT2017 09:28:53 15.7N 94.5W ML=4.0 UNAM l SUROESTE de ARRIAGA , CHIS *: 15

O: 17OCT2017 03:50:47 15.2N 94.6W ML=4.0 UNAM al SURESTE de SALINA CRUZ, OAX *:

O: 17OCT2017 07:53:49 14.9N 94.6W ML=4.1 UNAM al SURESTE de SALINA CRUZ, OAX *:

O: 17OCT2017 04:34:17 15.5N 94.8W ML=4.0 UNAM l SURESTE de SALINA CRUZ, OAX *: 1

O: 17OCT2017 07:26:44 15.3N 94.8W ML=4.0 UNAM l SURESTE de SALINA CRUZ, OAX *: 1

O: 17OCT2017 18:33:13 17.0N 94.9W ML=4.2 UNAM l NORESTE de MATIAS ROMERO, OAX *:

O: 17OCT2017 08:24:45 16.5N 95.0W ML=4.0 UNAM NORTE de JUCHITAN DE ZARAGOZA, OA

O: 17OCT2017 09:23:56 15.3N 95.0W ML=4.6 UNAM l SUR de SALINA CRUZ, OAX *: 15.32

O: 18OCT2017 06:53:21 16.5N 95.2W ML=4.0 UNAM l SUROESTE de CD IXTEPEC, OAX *: 1

O: 17OCT2017 11:52:30 15.8N 95.2W ML=4.2 UNAM l SUR de SALINA CRUZ, OAX *: 15.88

O: 17OCT2017 07:42:16 15.6N 95.3W ML=4.2 UNAM l SUR de SALINA CRUZ, OAX *: 15.68

O: 17OCT2017 15:13:46 16.0N 95.8W ML=4.1 UNAM l NORESTE de CRUCECITA, OAX *: 16.

O: 17OCT2017 23:23:55 15.3N 94.1W mb=4.2 EMSC OFFSHORE CHIAPAS, MEXICO

O: 17OCT2017 09:24:01 15.7N 94.7W mb=4.4 EMSC OFFSHORE OAXACA, MEXICO

O: 17OCT2017 07:42:16 15.7N 95.3W ML=4.2 EMSC OFFSHORE OAXACA, MEXICO

O: 17OCT2017 11:52:30 15.9N 95.2W ML=4.2 EMSC OFFSHORE OAXACA, MEXICO

O: 17OCT2017 15:13:46 16.0N 95.8W ML=4.1 EMSC OAXACA, MEXICO

O: 17OCT2017 08:24:45 16.5N 95.0W ML=4.0 EMSC OAXACA, MEXICO

O: 18OCT2017 06:53:21 16.5N 95.2W ML=4.0 EMSC OAXACA, MEXICO

AFRICA AND EUROPE

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

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

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

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

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

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

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

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

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

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

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

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

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

SOUTHWEST PACIFIC

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

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

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

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

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

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

OCEAN RIDGES

O: 17OCT2017 06:59:15 55.5S 29.7W mb=4.6 EMSC SOUTH SANDWICH ISLANDS REGION

P: 21OCT2017 111458 56.0S 27.0W 4.0-6.1 BABAA So. Sandwich Islands

ZEALANDIA AND AUSTRALIA REGION

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

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

JAPAN AND KURIL ISLANDS

O: 17OCT2017 23:48:51 42.3N 142.4E mb=4.9 EMSC HOKKAIDO, JAPAN REGION

P: 9OCT2017 111089 41.0N 143.0E 3.5-5.6 CBAAA Hokkaido, Japan

NEIC reported this earthquake of M 4.9 in Hokkaido, Japan was felt with intensity II-III in the area(s) of Sapporo, Hokkaido, Japan.

U.S./CANADA*

WESTERN U.S./CANADA

CALIFORNIA

O: 18OCT2017 07:20:59 33.1N 116.7W ML=2.1 EMSC SOUTHERN CALIFORNIA

O: 17OCT2017 12:05:40 33.1N 116.7W ML=3.1 EMSC SOUTHERN CALIFORNIA

P: 21OCT2017 111318 31.9N 116.3W 2.5-4.6 BBAAA So. California

NEIC reported this earthquake of M 3.1 in Southern California was felt with maximum intensity IV in Warner Springs, Descanso, and intensity II-III in the area(s) of Ranchita, Ramona, Julian, Alpine, Santa Ysabel, Poway, San Diego, La Mesa, Spring Valley, Carlsbad, Palm Desert, Idyllwild and Imperial Beach.

O: 17OCT2017 16:17:06 33.2N 115.6W ML=2.1 EMSC SOUTHERN CALIFORNIA

O: 17OCT2017 15:18:29 33.3N 115.6W ML=2.1 EMSC SOUTHERN CALIFORNIA

P: 19OCT2017 111318 32.5N 115.7W 2.5-4.6 AAAAA So. California

O: 17OCT2017 11:02:15 35.5N 118.4W ML=2.2 EMSC CENTRAL CALIFORNIA

P: 17OCT2017 111324 35.3N 118.6W 2.5-4.6 AAAAA So. California

O: 17OCT2017 10:18:40 36.4N 117.9W ML=2.1 EMSC CENTRAL CALIFORNIA

P: 15OCT2017 111288 36.3N 118.1W 2.5-4.5 AAAAA California/Nevada area

O: 17OCT2017 19:36:25 36.6N 121.2W MD=2.1 EMSC CENTRAL CALIFORNIA

O: 18OCT2017 02:06:54 36.7N 121.3W MD=2.0 EMSC CENTRAL CALIFORNIA

P: 16OCT2017 111293 36.4N 121.0W 2.5-4.4 AAAAA Central California

O: 18OCT2017 04:25:26 36.9N 117.8W ML=2.0 EMSC CENTRAL CALIFORNIA

P: 15OCT2017 111288 36.3N 118.1W 2.5-4.5 BAAAA California/Nevada area

P: 17OCT2017 111289 37.3N 118.3W 2.5-4.4 AAAAA California/Nevada area

O: 17OCT2017 07:27:26 37.5N 118.8W MD=2.2 EMSC CENTRAL CALIFORNIA

O: 17OCT2017 11:45:42 37.6N 118.9W ML=2.4 EMSC LONG VALLEY AREA, CALIFORNIA

P: 17OCT2017 111289 37.3N 118.3W 2.5-4.4 AAAAA California/Nevada area

O: 17OCT2017 23:28:53 38.0N 118.7W ML=2.0 EMSC CENTRAL CALIFORNIA

P: 14OCT2017 111291 38.4N 118.7W 2.5-4.4 BAAAA California/Nevada area

O: 18OCT2017 07:05:51 38.4N 122.7W MD=2.7 EMSC NORTHERN CALIFORNIA

P: 21OCT2017 111295 38.5N 122.7W 2.5-4.9 BAAAA Central California

NEIC reported this earthquake of M 2.7 in Northern California was felt with intensity II-III in the area(s) of Rohnert Park, Santa Rosa, Cotati, Penngrove, Glen Ellen, Sebastopol, Petaluma, Sonoma, San Francisco, California.

O: 18OCT2017 08:38:22 38.8N 122.7W Md=2.4 EMSC NORTHERN CALIFORNIA

O: 17OCT2017 21:46:37 38.8N 122.8W MD=2.9 EMSC NORTHERN CALIFORNIA

P: 19OCT2017 111295 38.9N 122.8W 2.5-4.7 AAAAA Central California

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

O: 18OCT2017 05:41:16 39.3N 122.8W MD=2.4 EMSC NORTHERN CALIFORNIA

P: 17OCT2017 111295 39.0N 123.1W 2.5-4.5 AAAAA Central California

O: 17OCT2017 22:59:37 41.7N 124.9W ML=2.3 EMSC OFFSHORE NORTHERN CALIFORNIA

P: 18OCT2017 111362 40.6N 124.9W 2.5-4.6 ABAAA Off Coast of No. Calif