2012 M6.3 Gulf of Alaska Earthquake

Mainshock and Aftershocks: 

A magnitude 6.3 earthquake occurred on Monday, November 12, 2012 at 11:41 am AKDT (20:42 UTC) in the Gulf of Alaska region of Alaska (red star on the map). It was located 288 km (180 miles) SW of Yakutat and 371 km (232 miles) SSE of Cordova. AEIC located about 110 aftershocks (open circles) within the following month, with the magnitudes ranging between 2.2 and 4.2. Due to the offshore location of this earthquake smaller aftershocks could not be detected.

Felt Reports: 

This earthquake was felt widely along the southern Alaska coast from Valdez and Cordova in the west to Sitka and Juneau in the east. Due to distant offshore location only weak intensity of felt shaking was reported.

Tectonic Setting: 

This is the largest event to occur in the region since the magnitude 7.7 and 7.8 earthquakes in 1988 and 1987, respectively (outlines of old ruptures are shown next to the year and magnitude). The 6.3 earthquake re-ruptured portion of the 1988 fault.

Source Mechanism: 

Waveform modeling indicates strike-slip faulting, similar to the 1987-88 events.