24-hour EQ cluster in Aleutians - tsunami & volcano history

[AlaskaDenise]

There have been 9 earthquakes, 4.0 to 5.1, just south of Adak Island during the last 24 hours. Kanaga volcano, about 56 miles NNE was showing some webicorder underground activity about 12 hours earlier, then stopped while the EQs started. Now it is showing something again (?harmonic tremor?). It's interesting that in the area south of the earthquake, there are 2 seamounts (Atka & Adams), putting the epicenter on a straight line between the seamounts and recently active Kanaga volcano.

To add more information: this area is near the Amela Fracture zone, which had tsunami-generating earthquakes: 8.8 in 1957 and 8.0 in 1986. A paper on the geology of this area shows the exact area of this quake: see page 3 diagram, to the right of Hawley Ridge where the blue arrow points - that is the epicenter of these quakes.

This activity may prove interesting to monitor.

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[AlaskaDenise]

Re: 24-hour EQ cluster in Aleutians - tsunami & volcano history

There are many large earthquakes and active volcanoes in this area, however the 1957 quake and tsunami is historic. The tsunami did considerable damage in Hawaii. see: http://earthquake.usgs.gov/earthquakes/states/events/1957_03_09.php

Andreanof Islands, Alaska
1957 03 09 14:22:31 UTC
Magnitude 8.6

This great earthquake destroyed two bridges on Adak Island, damaged houses, and left a 4.5 meter crack in a road. On Umnak Island, part of a dock was destroyed, and Mount Vsevidof erupted after being dormant for 200 years. Further, this shock generated a 15 meter tsunami that smashed into the coastline at Scotch Cap and an 8 meter tsumani that washed away many buildings and damaged oil lines extensively at Sand Bay. This tsunami continued to Hawaii, where is destroyed two villages and inflicted about $5 million in property damage on Oahu and Kauai Islands. The tsunami also caused minor damage in San Diego Bay, California, before traveling to such distant countries as Chile, El Salvador, Japan, and other areas in the Pacific region. More than 300 aftershocks were reported along the southern edge of the Aleutians, from Unimak Island to Amchitka Pass.

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