2014 M6.0 Palma Bay Earthquake

Mainshock and Aftershocks: 

A magnitude 6.0 earthquake occurred on Friday, July 25 at 2:54 am AKDT (10:54 UTC) near Palma Bay in southeastern Alaska (red star on the map). It occurred at a depth of 10 km (6 miles) and was located 42 km (26 miles) WNW of Elfin Cove, 133 km (83 miles) SW of Haines and 150 km (94 miles) W of Juneau. This earthquake was preceded by less than a minute by a magnitude 5.4 foreshock that occurred in the same location. The Alaska Earthquake Center recorded about 230 aftershocks within 1st month after the mainshock (open circles on the map). Only aftershocks with magnitudes about 2 or larger can be detected due to sparse seismic network coverage in the region. The largest aftershock measured at a magnitude 4.6 and occurred 3 minutes after the mainshock.

Felt Reports: 

This earthquake was felt widely throughout southeastern Alaska and Yukon communities. No reports of structural damage have been received. Maximum intensity of shaking, IV - light, was reported in Elfin Cove and Hoonah. This earthquake triggered an underwater landslide that severed a fiber optic cable of one of the local internet providers (ACS).

Tectonic Setting: 

This earthquake occurred in close proximity of the Fairweather fault. It is a prominent strike-slip fault that marks the boundary between Yakutat microplate to the west and North American plate to the east. The largest known earthquake that occurred along this portion of the fault was a magnitude 7.8 event in 1958.

Source Mechanism: 

The elastic-wave radiation pattern of the M6.1 event indicates oblique strike-slip faulting consistent with right-lateral strike-slip motion along the Fairweather fault.