Unalaska, AK – A strong earthquake shook Unalaska at about 4 a.m. this morning. The earthquake had a magnitude of 6.0. The U.S. Geological Survey reported its location at 12 miles northeast of Unalaska; the National Weather Service's West Coast and Alaska Tsunami Warning Center in Palmer said it originated at 15 miles east of the island. Because of the small number of seismic monitors in the Aleutians, pinpointing the exact source of a quake in the island chain is difficult.

The Aleutians sit along the Aleutian-Alaska Megathrust, the boundary between the North American tectonic plate and the Pacific Ocean plate. In the last century, two of the eight largest earthquakes on record have occurred in the Aleutians.