The August 30, 2013 M 7.0 earthquake southeast of Adak, Alaska, occurred
as the result of thrust faulting on or near the subduction zone interface
between the Pacific and North America plates. At the location of this event,
the Pacific plate moves towards the northwest with respect to North America at
the rate of approximately 73 mm/yr, beginning its descent into the mantle at the
Aleutian trench approximately 130 km south of the August 30 earthquake.
The depth and mechanism of this earthquake are consistent with occurring
along the megathrust interface between these two plates. The Aleutians Arc is
familiar with large earthquakes-two-dozen events of M 6.5 or larger have occurred
over the last century within 250 km of the August 30 earthquake. The largest among
these was a M 8.6 earthquake in March of 1957, whose hypocenter was located in just
15 km south of the August 30 earthquake.