The mainshock, magnitude 6.5, occurred on April 30 at 23:11:44 UTC. It was preceded by a magnitude 4.3 foreshock, 1 minute earlier, and followed by a magnitude 6.3 aftershock, 5 minutes later.
Due to the offshore location of these earthquakes, only larger events (magnitude 3.5 and greater) can be located. The nearest seismic stations are located about 350 miles away, at Gambell and St. Paul. As of May 5, 2010, only 10 aftershocks had been located by the Earthquake Center, however, all have large location uncertainties.
Last Modified: May 13, 2020