2005 M6.2 Unimak Island Earthquake

Mainshock and Aftershocks: 

The Alaska Earthquake Center located a strong earthquake that occurred on Sunday, November 20, 2005 at 3:53 AM local time (12:53 UTC) in the Unimak Island region of Alaska (red star on the above map). AEC located nearly 100 aftershocks (open circles) through the end of the month (M>=1.9). The largest aftershock of magnitude M5.6 occurred on November 22 at 6:09 AM local time (15:09 UTC, white star).


Felt Reports: 

The mainshock was felt strongly in Unalaska and False Pass. Several aftershocks were also felt.

Tectonic Setting: 

The M 6.2 earthquake occurred on the convergent boundary between the subducting Pacific and overriding North American crustal plates. This region, where the two plates are being forced directly into one another, is one of the world's most active seismic zones. Over one hundred earthquakes of magnitude seven or larger have occurred along this boundary in the past hundred years.