EQ Alaska region Aleutian islands , 6.4 near Tanaga Volcano: correction

A strong preliminary 6.9 magnitude earthquake, later revised to a 6.4 magnitude, struck near Adak, Alaska in the Aleutian Islands on Wednesday afternoon, but a damaging tsunami was not expected.

The USGS reported that the quake struck at 3:40 p.m. local time at a depth of 25 miles. The epicenter was 21 miles south of the Tanaga Volcano in Alaska in the Aleutian Island chain and 80 miles southwest of Adak, Alaska.

The West Coast and Alaska Tsunami Warning Center said that based on the earthquake magnitude, location, and historic tsunami records, a damaging tsunami was not likely along the California, Oregon, Washington, British Columbia, or Alaska coastlines. Some areas could experience non-damaging sea level changes though.


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Location: Adak, Alaska
51.88000869751 ; -176.65757751465
At this time, no watches, warnings, advisories were in effect.

Earthquakes are not uncommon in this region where the Pacific plate subducts into the mantle beneath the North America plate. This subduction is responsible for the generation of the Aleutian Islands and the deep offshore Aleutian Trench.

The USGS points out that most of the seismicity along the Aleutian arc results from thrust faulting that occurs along the interface between the Pacific and North America plates, extending from near the base of the trench to depths of 40 to 60 km. Slip along this interface is responsible for generating devastating earthquakes. (Source: USGS)
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