- Earthquake summary

STRONG SEISMICITY OFF NW U.S. COAST FOLLOWS M 4.6 IN NORTHERN KANSAS

EARTHQUAKE SUMMARY FOR JUNE 22, 2019

A series of moderately strong earthquake struck the northwestern coast of the United States today. These included an M 5.6 off the coast of California and two of M 5.4 off the coast of Oregon. This activity began with an M 4.2 two days ago and was anticipated as tidally-promoted seismicity in previous issues of this summary as it was noted in the previous issue:

"The strongest earthquake in the U.S. outside Alaska today was an M 3.2 off the coast of Oregon. This event was part of an activation of the area this summary noted in the previous issue as:

"The strongest earthquake in the U.S. or Canada today was an M 4.2 off the coast of Oregon. It was not reported felt in this epicentral area. The last earthquake of M>=4.2 within about 150 km of this epicenter was an M 4.7 on April 10, 2019.

Forecast 116738 expected today's event within about 25 km was likely around June 16. It is likely that this event which occurred near local solar midnight was tidally promoted as it occurred at the longitude of maximum tidal stress. Ths tidal forecast for the current full moon had read:" (June 21, 2019)

"The full moon will arrive on June 17 at 08:31 U.T. Longitudes which area sub-solar at this time are near 52 East and those anti-solar at 128 West longitude. These include area of Iran and the Caucasus in Asia and Europe and the west coast of the U.S. in the west. These are regions most likely to see tidal promotion of seismicity during the coming week. Other areas can also see tidal triggering. These are most likely near local solar midnight and noon and generally include areas of vertical tectonics such as subduction zones." (June 15-17, 2019)

Note this area includes the coast of Oregon and the coast of Northern California both of which could still see tidal triggering associated with the full moon. Forecast 116737 had expected activity near today's epicenter around June 17." (June 21-22, 2019)

The activity in the northwestern U.S. coast was preceded by an unusual M 4.6 in northern Kansas. The only other event within this general region of similar magnitude in the past 30 years was an M 4.1 on June 30, 2018 about 250 km northwest of this in Nebraska. At the time this summary noted in regard to subsequent activity:

"The most unusual and largest earthquake in the U.S. or Canada outside Hawaii today was an M 4.2 in Nebraska. NEIC reported it was felt with intensity IV in Nebraska at Arnold and North Platte and II-III in Callaway, Stapleton, Brady. Earthquakes

in this area often precede by hours to days moderate to strong earthquakes along the western rim of the North American Plate. These are usually in the region of Alaska but can occur as far south as California." (June 30,, 2018)

The strongest earthquake in the world today was an M 5.6-5.8 off the coast of Northern California. NEIC reported it was felt with intensity VII in Petrolia; V in Ferndale, Rio Dell, Myers Flat, Redcrest, Whitethorn; IV in Fortuna, Hydesville and Scotia among other communities in northern California. It was reported felt lightly as far as Oregon and Nevada.

An M 3.3 foreshock about 30 minutes before the M 5.6 was reported felt with intensity V in Loleta and IV in Petrolia and II-II in Ferndale, Rio Dell, Hydesville, Fortuna, Carlotta and Eureka, California. This is the strongest earthquake off the coast of Northern California within about 150 km of this epicenter since an M 5.7 on September 3, 2016. The last of significantly larger magnitude was an M 6.8 on March 10, 2014. Forecast 116971 had expected today's activity was likely within about 50 km around June 23.

O: 23JUN2019 03:53:03 40.2N 124.3W Mw=5.6 EMSC NORTHERN CALIFORNIA

O: 23JUN2019 03:27:31 40.3N 124.3W ML=3.3 EMSC NORTHERN CALIFORNIA

P: 23JUN2019 116971 40.7N 124.6W 2.5-4.5 AAAAA Off Coast of No. Calif

A series of moderate earthquakes also occurred today off the coast of Oregon. Some of these may have been felt lightly along the Oregon coast at Clatskanie and Portland and possibly in Washington State. The largest of these were two events of M 5.0-5.4 each. NEIC reported they were lightly felt in Brookings, Oregon. The last earthquakes of M>=5 within about 150 km of today's epicenters occurred on August 22, 218 with M 6.2 and July 29, 2018 (M 5.3). Forecasts 116738 and 116972 had expected the area would experience moderate seismicity between June 16 and 27.

O: 22JUN2019 13:16:10 43.8N 128.7W mb=4.2 EMSC OFF COAST OF OREGON

O: 22JUN2019 14:14:07 43.9N 128.3W ML=3.2 EMSC OFF COAST OF OREGON

O: 22JUN2019 12:52:03 43.9N 128.5W mb=4.9 EMSC OFF COAST OF OREGON

O: 22JUN2019 12:52:02 43.8N 128.3W mb=5.4 ANSS OFF COAST OF OREGON

O: 22JUN2019 13:00:16 43.9N 128.6W mb=5.1 EMSC OFF COAST OF OREGON

O: 22JUN2019 13:00:17 43.9N 128.4W mb=5.4 ANSS OFF COAST OF OREGON

O: 22JUN2019 13:40:13 43.9N 128.7W mb=4.7 EMSC OFF COAST OF OREGON

O: 23JUN2019 02:12:27 44.0N 128.2W ML=3.1 EMSC OFF COAST OF OREGON

O: 22JUN2019 12:43:44 44.0N 128.4W Mw=5.0 EMSC OFF COAST OF OREGON

O: 22JUN2019 14:26:46 44.1N 128.5W mb=4.6 EMSC OFF COAST OF OREGON

O: 22JUN2019 13:37:31 43.8N 128.6W mb=4.2 EMSC OFF COAST OF OREGON

P: 16JUN2019 116738 43.9N 128.4W 3.0-4.4 CAAAA Off Coast of Oregon

P: 27JUN2019 116972 44.5N 129.8W 3.0-4.8 BAAAA Off Coast of Oregon

An earthquake of M 4.5 also occurred today in the area of northern Kansas. This is an unusual event in both location and magnitude. NEIC reported intensity V in Kansas at Palco, Plainville, Damar; IV in Sockton, Bogue, Hill City, Ogallah, and III in Ellis, Woodston, and Hayes. It was widely It was widely felt as far as Missouri, Nebraska, Iowa, Colorado, Kansas, Oklahoma, and possibly in Texas. It was preceded by an M 2.6 in western Tennessee felt in Paris, Tennessee lightly. As noted in previous issues of this summary, moderate earthquakes in the area of Kansas, Nebraska and South Dakota are often followed within hour by moderate to strong quakes along the western boundary of North America - often in the regions off the coast of Oregon and Washington and this appears to be the case in this instance. Today's earthquake in Kansas is the strongest within about 200 km in northern Kansas or Nebraska in at least 30 years. Forecast 116942 had expected regional seismicity in late June. This earthquake in Kansas is located at 101 degrees from the M 7.2 in the

Kermadec Islands of June 15 and at 106 degrees from the M 7.5 in New Britain. Seismic energy from large earthquakes concentrates at this distance on the surface after internal reflections and refractions and can help promote seismicity in this distance range fromo the mainshock.

O: 22JUN2019 08:50:23 39.3N 99.4W mb=4.6 EMSC KANSAS

P: 28JUN2019 116942 37.0N 97.0W 2.0-3.9 CCBAA Southern Plains

An M 5.6 also occurred today off southern Chiapas, Mexico. NEIC reported it was felt with intensity II-III in Mexico City and in Villhermosa, Tabasco, Mexico. The last earthquake of larger magnitude in Chiapas was an M 6.6 on February 1, 2019.

Forecasts 116645 and 116863 had expected this area to be activity within about 50 km of this epicenter in mid-June.
This epicenter, like those in Northern California and off Oregon is located at the fourth node from the Kermadec Islands

And was probably promoted from that source region.

O: 22JUN2019 21:48:30 14.4N 92.8W mb=4.8 EMSC OFFSHORE CHIAPAS, MEXICO

O: 22JUN2019 22:31:41 14.5N 92.8W Mw=5.5 EMSC OFFSHORE CHIAPAS, MEXICO

O: 23JUN2019 06:03:38 14.6N 93.2W ML=4.4 EMSC OFFSHORE CHIAPAS, MEXICO

P: 19JUN2019 116645 14.0N 93.0W 3.5-5.2 BAAAA Chiapas, Mexico

P: 21JUN2019 116863 16.0N 93.0W 3.5-5.2 ABAAA Chiapas, Mexico

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: 22JUN2019 22:22:39 23.7N 122.8E mb=4.1 EMSC TAIWAN REGION

O: 22JUN2019 21:00:02 23.7N 123.0E mb=4.3 EMSC TAIWAN REGION

O: 22JUN2019 21:00:05 23.8N 122.9E ML=4.3 TAI Hualien, Taiwan

O: 22JUN2019 22:22:41 23.8N 122.9E ML=4.5 TAI Hualien, Taiwan

P: 19JUN2019 116675 25.0N 124.0E 4.0-5.6 BBAAA Ryukyu Islands

P: 25JUN2019 116890 25.0N 123.0E 4.0-5.6 BBAAA Ryukyu Islands

CWB reported this earthquake of M 4.3 was felt within intensity I in Hualien, Taitung and Nontou Counties, Taiwan.

The M 4.5 was felt within intensity I in Hualien, II in Taitung and I in Taichung Counties, Taiwan.

O: 23JUN2019 00:28:21 28.5N 105.0E mb=4.9 EMSC SICHUAN-GUIZHOU BORDER RG, CHI

O: 22JUN2019 14:29:56 28.5N 105.0E mb=5.3 EMSC EASTERN SICHUAN, CHINA

P: 21JUN2019 116888 27.0N 104.0E 4.0-5.4 ABAAA Myanmar

NEIC reported this earthquake of M 5.3 in Eastern Sichuan, China was felt with intensity VI in Yngchang, Chongqing; IV in Luocheng, Sichuan and II-III in the area(s) of Luzhou, Huayang and Chengdu, Sichuan and in Chongqing at Chongqing and Shiongshui, Hong Kong, China.

INDONESIA AND PHILIPPINES

O: 22JUN2019 15:43:55 4.5N 127.6E mb=4.5 EMSC KEPULAUAN TALAUD, INDONESIA

P: 25JUN2019 116833 6.0N 127.0E 4.0-5.4 BAAAA Halmahera

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

CENTRAL AND SOUTH AMERICA

O: 23JUN2019 06:51:00 6.9N 73.2W ML=4.0 EMSC NORTHERN COLOMBIA

P: 25JUN2019 116830 7.0N 73.0W 4.0-5.5 AAAAA Colombia

O: 22JUN2019 21:48:30 14.4N 92.8W mb=4.8 EMSC OFFSHORE CHIAPAS, MEXICO

O: 22JUN2019 22:31:41 14.5N 92.8W Mw=5.5 EMSC OFFSHORE CHIAPAS, MEXICO

O: 23JUN2019 06:03:38 14.6N 93.2W ML=4.4 EMSC OFFSHORE CHIAPAS, MEXICO

P: 19JUN2019 116645 14.0N 93.0W 3.5-5.2 BAAAA Chiapas, Mexico

P: 21JUN2019 116863 16.0N 93.0W 3.5-5.2 ABAAA Chiapas, Mexico

O: 22JUN2019 16:23:26 15.2N 94.5W ML=4.1 EMSC OFF COAST OF OAXACA, MEXICO

O: 22JUN2019 19:20:18 16.6N 94.5W ML=4.0 EMSC OAXACA, MEXICO

O: 22JUN2019 17:54:30 16.8N 94.7W ML=4.0 EMSC OAXACA, MEXICO

P: 25JUN2019 116863 15.0N 95.0W 3.5-5.1 BAAAA Chiapas, Mexico

O: 22JUN2019 08:26:13 17.4N 100.8W ML=4.2 EMSC GUERRERO, MEXICO

P: 22JUN2019 116875 17.0N 100.0W 3.5-5.3 AAAAA Oaxaca, Mexico

O: 22JUN2019 22:16:11 19.7N 70.8W ML=3.1 EMSC DOMINICAN REPUBLIC

P: 21JUN2019 116882 20.0N 71.0W 3.0-4.6 AAAAA Bahamas/No. Caribbean

AFRICA AND EUROPE

O: 22JUN2019 20:00:00 37.6N 1.7W ML=3.8 EMSC SPAIN

P: 27JUN2019 116915 36.0N 4.0W 3.5-4.9 BBBAA Morocco/Spain

NEIC reported this earthquake of M 3.4 in Southern Spain was felt with intensity II-III in the area(s) of Aguilas, Murcia and Turre Almeria, Spain.

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

SOUTHWEST PACIFIC

O: 23JUN2019 00:21:06 21.1S 173.8W Mw=4.9 EMSC TONGA

P: 20JUN2019 116806 22.0S 175.0W 4.0-5.6 BAAAA Tonga Islands

O: 22JUN2019 16:36:21 21.9S 179.4W mb=4.9 EMSC FIJI REGION

P: 28JUN2019 117039 23.0S 177.0W 4.0-5.8 CBBAA Tonga Islands

O: 22JUN2019 18:34:32 16.9S 171.5E mb=5.0 EMSC VANUATU REGION

P: 27JUN2019 117029 16.0S 168.0E 4.0-5.5 BACAA Vanuatu Islands

OCEAN RIDGES

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

ZEALANDIA AND AUSTRALIA REGION

O: 22JUN2019 22:35:04 30.9S 177.1W mb=4.9 EMSC KERMADEC ISLANDS, NEW ZEALAND

O: 23JUN2019 06:52:10 31.2S 177.4W Mw=5.3 EMSC KERMADEC ISLANDS REGION

P: 25JUN2019 117050 31.0S 177.0W 4.0-5.4 AAAAA So. Kermadec Islands

O: 22JUN2019 20:41:42 40.1S 175.7E mb=4.1 EMSC NORTH ISLAND OF NEW ZEALAND

O: 22JUN2019 22:31:39 43.0S 171.2E ML=4.1 GEONET Felt with light intensity

P: 29JUN2019 117052 40.0S 175.0E 3.0-4.7 CAAAA North Island, N.Z.

GEONET reported this earthquake was felt with light intensity in the area of north-western South Island, New Zealand. 7 people reported feeling this earthquake including 5 with weak intensity; 2 with light shaking; 0 moderate and 0 extreme, severe or strong.

JAPAN AND KURIL ISLANDS

O: 22JUN2019 14:30:22 44.7N 148.9E mb=4.6 EMSC KURIL ISLANDS

P: 23JUN2019 116978 45.0N 149.0E 3.5-5.6 AAAAA So. Kurils

U.S./CANADA*

WESTERN U.S./CANADA

CALIFORNIA

O: 22JUN2019 12:05:14 33.2N 115.6W ML=3.0 EMSC SOUTHERN CALIFORNIA

P: 22JUN2019 116930 32.9N 115.6W 2.5-4.5 AAAAA So. California

NEIC reported this earthquake of M 3.0 in Southern California was felt with intensity IV in Calipatria and II-III in the area(s) of Westmorland, California.

O: 22JUN2019 13:29:23 36.9N 121.6W Ml=3.1 EMSC CENTRAL CALIFORNIA

P: 25JUN2019 116903 37.1N 121.5W 2.5-4.9 BAAAA Central California

O: 22JUN2019 21:06:20 37.1N 116.1W ml=2.0 EMSC NEVADA

P: 21JUN2019 116937 35.5N 116.4W 2.5-4.4 ABAAA So. California

O: 22JUN2019 16:18:53 37.3N 118.4W Md=2.1 EMSC CENTRAL CALIFORNIA

P: 24JUN2019 116898 37.9N 118.2W 2.5-4.4 AAAAA California/Nevada area

O: 22JUN2019 09:23:57 38.2N 115.8W ml=2.1 EMSC NEVADA

P: 23JUN2019 116899 38.7N 115.4W 2.5-4.4 AAAAA California/Nevada area

O: 23JUN2019 03:53:03 40.2N 124.3W Mw=5.6 EMSC NORTHERN CALIFORNIA

O: 23JUN2019 03:27:31 40.3N 124.3W ML=3.3 EMSC NORTHERN CALIFORNIA

P: 23JUN2019 116971 40.7N 124.6W 2.5-4.5 AAAAA Off Coast of No. Calif

ALASKA

O: 22JUN2019 17:01:40 51.8N 170.5W mb=3.9 EMSC FOX ISLANDS, ALEUTIAN ISLANDS

P: 18JUN2019 116754 52.1N 171.3W 3.5-4.9 BAAAA Andreanoff Isls, Aleutians

O: 22JUN2019 19:01:58 52.4N 172.6W ML=3.2 EMSC ANDREANOF ISLANDS, ALEUTIAN IS

P: 24JUN2019 116986 52.2N 173.9W 3.5-4.9 AAAAA Andreanoff Isls, Aleutians

O: 22JUN2019 16:26:22 59.8N 141.0W ML=2.9 EMSC SOUTHEASTERN ALASKA

P: 22JUN2019 116999 59.0N 137.0W 3.0-4.9 AABAA Southeast Alaska

O: 22JUN2019 07:45:43 64.9N 164.8W ML=3.1 EMSC NORTHERN ALASKA

PACIFIC NORTHWESTERN U.S./WESTERN CANADA

O: 22JUN2019 16:18:06 43.9N 125.2W Ml=2.4 EMSC OFFSHORE OREGON

P: 26JUN2019 116972 41.8N 126.9W 2.5-4.4 BCAAA Off Coast of No. Calif