Monday, March 30, 2015
Sunday, March 29, 2015
Seismic Alert: Strong M7.7 Earthquake strikes Papua New Guniea, prompting Tsunami Warning | USGS
Tsunami Warning Issued after M7.7 Earthquake - Papua New Guinea
29.03.2015
The USGS has since downgraded the event to M7.5
TSUNAMI THREAT FORECAST...UPDATED
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*THE TSUNAMI THREAT HAS NOW LARGELY PASSED.
The U.S. Geological Survey says a magnitude 7.7 #earthquake has struck in Papua New Guinea. The earthquake prompted a #tsunami warning.The USGS says the quake’s epicenter was located 33 miles (54 kilometers) southeast of Kokopo, Papua New Guinea and was at a depth of 65 kilometers. The quake hit at 3:48 p.m. PST Sunday.A tsunami alert was issued for coastal areas within 1,000 kilometers of the quake’s epicenter. There was no threat for the California coast.A tsunami alert was issued for coastal areas within 1,000 kilometers of the quake’s epicenter. There was no threat for the California coast.The USGS says the quake’s epicenter was located 33 miles (54 kilometers) southeast of Kokopo, Papua New Guinea and was at a depth of 65 kilometers. The quake hit at 3:48 p.m. PST Sunday.A tsunami alert was issued for coastal areas within 1,000 kilometers of the quake’s epicenter. There was no threat for the California coast.A tsunami alert was issued for coastal areas within 1,000 kilometers of the quake’s epicenter. There was no threat for the California coast.
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A USGS map of an earthquake that hit M7.7 Earthquake (downgraded to M7.5) - Papua New Guinea. (Source: USGS) |
Tectonic Summary
The March 29, 2015 M 7.5 earthquake southeast of Kokopo, Papua New Guinea, occurred as the result of thrust faulting on or near the plate boundary interface between the subducting Australia and overriding Pacific plates. At the location of the earthquake, the Australia plate moves towards the east-northeast at a velocity of 105 mm/yr with respect to the Pacific plate, and begins its subduction into the mantle beneath New Britain and New Ireland at the New Britain Trench south of the earthquake. The moment tensor and depth of the event are consistent with thrust-type motion on the interface between these two plates. Note that at the location of the earthquake, some researchers divide the edges of the Australia and Pacific plates into several microplates that take up the overall convergence between Australia and the Pacific, including the Solomon Sea and South Bismark microplates local to this event. The Solomon Sea plate moves slightly faster and more northeasterly with respect to the Pacific plate than does Australia due to sea-floor spreading in the Woodlark Basin several hundred kilometers to the south of the March 29 earthquake, facilitating the classic subduction evident beneath New Britain and New Ireland.
The plate boundary between the Australia and Pacific plates in the Papua New Guinea region is very active seismically; 36 M 7+ events have occurred within 250 km of the March 29, 2015 earthquake over the past century. Few are known to have caused shaking-related fatalities because of the remoteness of the region, though a M 8.0 earthquake in November 2000 – one of three similarly sized events over a 2-day period – did cause several deaths. The largest nearby earthquake was an M 8.1 event, 70 km to the east of the March 29, 2015 earthquake, one of two M8+ earthquakes 140 km apart in July 1971.
https://www.youtube.com/watch?v=NBpAhMRLKZo
USGS information on the 7.5 Magnitude earthquake: http://earthquake.usgs.gov/earthquakes/eventpage/us10001rvu#general_summary
Tsunami Information 29.03.2015
TSUNAMI MESSAGE NUMBER 4 NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI 0230 UTC MON MAR 30 2015
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