- Earthquake summary

MAJOR M 7.2 IN KERMADEC ISLANDS REPLATED TO PERU

EARTHQUAKE SUMMARY FOR JUNE 15, 2019

An M 7.2 earthquake in the Kermadec Islands of New Zealand today followed about an hour after an M 6.1 to the north in Tonga. The Kermadec events was associated with a series of moderate to large aftershocks including an M 6.4. This activity

was not reported felt in the remote epicentral region. The epicenter is located at 99 degrees from the M 8.0 in Peru of May 26 and was probably triggered by concentrated seismic energy from that event. Readers of this summary know that

the distance 101-103 degrees is often cited as a distance at which seismic waves reflected and refracted off the core-mantle boundary return to the surface and are concentrated. For deep focus earthquakes, the path is slightly different

and the focus on or near the surface of the reflections and refractions is near 99 degrees. It was for this reason that this summary has emphasized this region as a prime target for seismic triggering from Peru. This was last noted in the previous issue when an M 5.0 foreshocks hit the Kermadec Islands as:

"The Tonga-Fiji-Kermadec arc in the southwestern Pacific continued to see enhanced seismicity today with a series of moderate events along the area from Tonga and Samoa south to the Kermadec Islands. Following the M 8.0 in Peru of May 26, this summary has argued that this arc was likely to see strong triggering due to its distance (100-104 degrees) from the Peruvian epicenter. This appears to be the case with a number of moderate quakes in New Zealand in recent days. An example of this was noted on May 30, 2019 in this summary as:

"... three moderate earthquake in New Zealand - in the Kermadec Islands of M 5.0 and in North Island of 4.2 and 4.4-4.5. ... This activity is at 101-102 degrees from the M 8.0 in Peru of May 26 and was probably promoted by concentrated seismic energy from that event, as expected in previous issues of this summary:

The 103 distance from Peru passes through the epicenter of the M 6.1 in the Andreanof Islands which occurred about a day before Peru; through the Komandorsky Islands of Russia, south to the Tonga-Fiji arc and through New Zealand where a

moderate to large earthquake could be promoted in the near term. In the east it passes along the East African Rift north to western Turkey and the Anatolian region." (May 26-27, May 29-30, June 1, 10, 15, 2019)

The M 7.2 in the Kermadec Islands occurred within minutes of local solar noon and was probably promoted by tidal stresses which maximize at this hour. The current tidal forecast for the coming full moon reads:

"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 15-16, 2019)

The earthquake of M 7.2 in the Kermadec Islands, New Zealand is the largest in the world since an M 8.0 on May 26 beneath Peru. It is also the strongest in the Kermadec Islands since an M 7.4 on October 21, 2011 and the strongest within about 150 km of this epicenter since an M 7.4 on May 16, 2006. A series of forecasts (116597, 116600, 116813 and 116816) had expected this activity in mid-June.

O: 16JUN2019 03:02:38 30.7S 178.1W Mw=5.3 EMSC KERMADEC ISLANDS, NEW ZEALAND

O: 15JUN2019 22:54:59 30.8S 178.0W Mw=7.2 EMSC KERMADEC ISLANDS, NEW ZEALAND

O: 15JUN2019 23:07:20 30.8S 178.1W mb=5.3 EMSC KERMADEC ISLANDS, NEW ZEALAND

O: 15JUN2019 23:59:59 30.9S 177.7W mb=5.0 EMSC KERMADEC ISLANDS, NEW ZEALAND

O: 16JUN2019 00:12:50 30.9S 178.0W mb=4.6 EMSC KERMADEC ISLANDS, NEW ZEALAND

O: 16JUN2019 01:29:38 31.0S 177.7W mb=5.0 EMSC KERMADEC ISLANDS, NEW ZEALAND

O: 16JUN2019 05:17:15 31.1S 178.1W Mw=6.4 EMSC KERMADEC ISLANDS REGION

P: 11JUN2019 116597 30.0S 178.0W 4.0-5.4 BAAAA No. Kermadec Islands

P: 11JUN2019 116600 31.0S 180.0W 4.0-5.4 AAAAA So. Kermadec Islands

P: 14JUN2019 116813 30.0S 178.0W 4.0-6.4 AAAAA No. Kermadec Islands

P: 15JUN2019 116816 31.0S 178.0W 4.0-5.5 AAAAA So. Kermadec Islands

The M 7.2 in the Kermadec Islands was preceded about an hour earlier by an M 6.1 in the central Tonga Islands. It was not reported felt in this remote epicentral area. This event may have been a regional trigger for the succeeding M 7.2 to the south. The area has been active in recent days with a series of moderate events. The last of M>=6.1 however within about 150 km of this epicenter occurred to the north on December 23, 2018 and prior to that as an M 6.1 on November 10, 2018 after a three year lull at this magnitude level since July 6, 2015 (M 6.2). Forecast 116806 had expected this event within about 100 km of the epicenter was likely around June 14.

O: 15JUN2019 21:56:12 21.1S 174.6W Mw=6.1 EMSC TONGA

P: 14JUN2019 116806 20.0S 175.0W 4.0-5.9 ABAAA Tonga Islands

An unusual earthquake of M 3.6 in southern Texas was the strongest in the U.S. or Canada today. It occurred about two hours after the M 7.2 in the Kermadec Islands at a distance (97 degrees) suggesting triggering effects from that event. This is the strongest earthquake within about 150 km of this epicenter since an M 4.8 on October 20, 2011.

NEIC reported this earthquake of M 3.6 in Southern Texas was felt with intensity IV in Gillet, Texas and Hobson, Poth, Falls City, Kames City, Floresville, Campbellton and San Antonio, Texas.

O: 16JUN2019 01:07:18 29.0N 98.0W mb=3.6 EMSC SOUTHERN TEXAS

An unusual swarm of earthquake in southern Colorado today included an M 2.5. This activity near Alamosa East, Colorado began with an M 1.3 at local solar midnight and was probably promoted by tidal stresses which maximize at this hour. The last earthquake within about 50 km of this epicenter in Colorado with M>=2.5 was an M 3.6 on February 28, 2019. This epicenter is at 102 degrees from the M 7.5 in New Britain of May 14 and at the seventh node (51.4 degrees) from Peru may have been promoted from those events. Forecast 116688 had expected this event was likely within this area around June 15.

NEIC reported this earthquake of M 2.5 in Colorado was felt with intensity II-III in the area(s) of Mosca, Colorado.

O: 15JUN2019 16:57:17 37.7N 105.5W ml=1.7 ANSS Alamosa East Colorado

O: 15JUN2019 13:30:23 37.7N 105.5W ml=1.5 ANSS Alamosa East Colorado

O: 15JUN2019 08:45:49 37.7N 105.5W ml=1.1 ANSS Alamosa East Colorado

O: 15JUN2019 08:37:06 37.6N 105.5W ml=1.7 ANSS Alamosa East Colorado

O: 15JUN2019 08:18:50 37.7N 105.5W ml=2.5 ANSS Alamosa East Colorado

O: 15JUN2019 07:43:03 37.6N 105.5W ml=1.2 ANSS Alamosa East Colorado

O: 15JUN2019 07:42:18 37.6N 105.5W ml=1.4 ANSS Alamosa East Colorado

O: 15JUN2019 06:54:25 37.6N 105.6W ml=1.3 ANSS Alamosa East Colorado

P: 15JUN2019 116688 37.3N 104.8W 2.0-4.3 AAAAA Colorado area

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: 15JUN2019 07:08:27 31.0N 56.8E mb=4.5 EMSC CENTRAL IRAN

P: 14JUN2019 116676 28.0N 56.0E 3.5-5.1 ACAAA So. Iran/Persian Gulf

O: 15JUN2019 07:52:29 36.2N 71.0E mb=4.3 EMSC HINDU KUSH REGION, AFGHANISTAN

P: 8JUN2019 116448 36.0N 71.0E 3.8-5.3 CAAAA Hindu Kush/Pakistan

P: 20JUN2019 116690 37.0N 72.0E 3.8-5.3 BAAAA Hindu Kush/Pakistan

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

INDONESIA AND PHILIPPINES

O: 15JUN2019 17:11:57 1.8S 122.6E ML=4.1 EMSC SULAWESI, INDONESIA

P: 19JUN2019 116639 2.0S 123.0E 4.0-5.5 BAAAA Sulawesi area

O: 16JUN2019 00:35:09 2.2N 126.9E ML=4.1 EMSC MOLUCCA SEA

P: 18JUN2019 116618 1.0N 127.0E 4.0-5.6 ABAAA Halmahera

O: 16JUN2019 05:12:44 4.2N 126.8E ML=4.3 EMSC KEPULAUAN TALAUD, INDONESIA

O: 15JUN2019 20:43:16 5.1N 126.3E ML=4.3 EMSC MINDANAO, PHILIPPINES

P: 16JUN2019 116620 5.0N 125.0E 4.0-5.6 AABAA Mindanao, Philippines

O: 15JUN2019 17:40:05 8.2S 116.3E ML=4.1 EMSC LOMBOK REGION, INDONESIA

P: 19JUN2019 116639 8.0S 119.0E 4.0-5.6 BACAA Sumbawa Island area

O: 15JUN2019 14:04:20 8.7S 118.1E ML=4.1 EMSC SUMBAWA REGION, INDONESIA

P: 19JUN2019 116639 8.0S 119.0E 4.0-5.6 BAAAA Sumbawa Island area

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

CENTRAL AND SOUTH AMERICA

O: 15JUN2019 07:07:00 4.1S 77.0W ML=4.5 EMSC NORTHERN PERU

P: 13JUN2019 116625 4.0S 80.0W 4.0-5.4 AACAA Ecuador

O: 15JUN2019 23:24:30 10.5N 86.1W ML=4.1 EMSC OFF COAST OF COSTA RICA

P: 16JUN2019 116659 10.0N 86.0W 3.5-5.1 AAAAA Nicaragua

O: 15JUN2019 15:50:58 14.1N 93.3W ML=4.0 EMSC OFF COAST OF CHIAPAS, MEXICO

O: 15JUN2019 15:53:11 14.2N 93.5W ML=4.0 EMSC OFF COAST OF CHIAPAS, MEXICO

P: 17JUN2019 116645 15.0N 94.0W 3.5-5.4 AAAAA Chiapas, Mexico

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

O: 16JUN2019 00:28:45 15.2N 98.8W ML=4.1 EMSC OFF COAST OF OAXACA, MEXICO

P: 13JUN2019 116662 16.0N 98.0W 3.5-5.4 BAAAA Oaxaca, Mexico

O: 15JUN2019 19:41:07 18.2N 68.3W ML=3.0 EMSC MONA PASSAGE, DOMINICAN REPUBL

P: 20JUN2019 116664 19.0N 68.0W 3.4-5.1 BAAAA Puerto Rico

O: 16JUN2019 01:45:57 18.6N 64.2W Md=3.0 EMSC VIRGIN ISLANDS REGION

P: 16JUN2019 116653 18.0N 65.0W 3.0-5.1 AAAAA Leeward Islands

O: 16JUN2019 01:50:35 19.0N 70.5W ML=3.0 EMSC DOMINICAN REPUBLIC

P: 16JUN2019 116667 20.0N 71.0W 3.0-4.7 AAAAA Bahamas/No. Caribbean

O: 15JUN2019 16:22:53 21.5S 66.8W mb=4.5 EMSC POTOSI, BOLIVIA

P: 17JUN2019 116796 21.0S 67.0W 4.0-5.5 AAAAA Argentina

O: 15JUN2019 16:58:02 28.4S 67.4W mb=4.7 EMSC LA RIOJA, ARGENTINA

P: 14JUN2019 116796 28.0S 67.0W 4.0-5.4 AAAAA Argentina

O: 15JUN2019 10:37:14 30.0S 72.1W mb=4.8 EMSC OFFSHORE COQUIMBO, CHILE

P: 13JUN2019 116812 30.0S 72.0W 4.0-6.4 AAAAA Coast Central Chile

O: 16JUN2019 00:58:41 31.5S 72.6W mb=4.4 EMSC OFFSHORE COQUIMBO, CHILE

P: 19JUN2019 116809 31.0S 72.0W 4.0-5.4 BAAAA Central Chile

AFRICA AND EUROPE

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

SOUTHWEST PACIFIC

O: 15JUN2019 21:56:12 21.1S 174.6W Mw=6.1 EMSC TONGA

P: 14JUN2019 116806 20.0S 175.0W 4.0-5.9 ABAAA Tonga Islands

O: 15JUN2019 18:33:15 25.1S 179.7E mb=4.8 EMSC SOUTH OF FIJI ISLANDS

P: 13JUN2019 116808 24.0S 179.0E 4.0-5.6 ABAAA Tonga/Fiji

OCEAN RIDGES

O: 16JUN2019 06:30:19 44.7S 35.5E mb=5.0 EMSC PRINCE EDWARD ISLANDS REGION

P: 5JUN2019 116606 51.0S 29.0E 4.0-5.6 DCCAA Atlantic-Indian Ridge

ZEALANDIA AND AUSTRALIA REGION