This is the largest event to occur in the area since the magnitude 6.6 earthquakes on April 15 and May 2, 2008 (yellow stars). The faulting parameters of these earthquakes estimated from the waveform inversion indicate strike-slip type of faulting. Their locations, shallow and above the down-dip end of the locked plate interface, are consistent with the events occurring within the crust of overriding North American plate.

Similar earthquakes have occurred in the past in western and central Aleutian arc. In western Aleutians, the crust is partitioned into rotating blocks. In addition, direction of convergence between the two tectonic plates is oblique to the plate interface in this region. The 2008 and 2012 strike-slip events manifest deformation along the Aleutian arc that accommodates relative motions of the crustal blocks and/or slip partitioning between the plate subduction and strike-slip motion.