2007 M7.1 Andreanof Islands Earthquake

The M7.1 earthquake occurred in the area separating the rupture zones of the 1965 M8.7 Rat Islands earthquake to the west and the 1957 M8.6 Andreanof Islands earthquake to the east. The most significant recent earthquakes in the area, M6.6 July 8, 2006 and M6.7 August 2, 2007, occurred to the east and west of the M7.1 event, respectively. The westernmost area of the 1957 fault zone reruptured repeatedly in the 1986 M8.0 and 1996 M7.9 earthquakes. The eastern portion of the 1965 fault zone was reruptured recently in the M7.7 earthquake on November 17, 2003.

All these events occurred along the megathrust boundary between the subducting Pacific and overriding North American plates. In the 10 years prior, the region experienced an average of two M6 or greater events per year. The Aleutian megathrust, where the two plates are being forced directly into one another, is one of the world's most active seismic zones.