2012 M6.2 Fox Islands Earthquake

Mainshock and Aftershocks: 

A magnitude 6.2 earthquake occurred on Friday, August 10, 2012 at 10:37 am AKDT (18:37 UTC) in the Fox Islands region of Alaska (red star on the map). It was located 114 km (71 miles) ESE of Nikolski and 169 km (106 miles) SSW of Dutch Harbor. No reports of this event being felt have been received. It was an aftershock-poor event, only 20 aftershocks (open circles) were located through the end of August, the largest had magnitude of 3.6.

Tectonic Setting: 

This is the largest event to occur in the region since the magnitude 6.4 and 6.5 earthquakes on October 13, 2009 (yellow stars). The August 10 M6.2 earthquake occurred on convergent boundary between the subducting Pacific and overriding North American crustal plates. This region, where Pacific plate is being forced under the North American plate, is one of the world's most active seismic zones. In 1957, magnitude 8.6 Andreanof Islands earthquake ruptured a ~600 km-long portion of the plate boundary in the central Aleutian Islands. The 2009 and 2012 earthquakes are located near eastern end of the 1957 rupture zone.

Source Mechanism: 

Waveform modeling indicates thrust type of faulting, consistent with the slip on the plate interface.