A tsunami advisory was issued for Alaska's Aleutian Islands, with possible tsunami activity occurring in Shemya, Alaska, at 12:25 AKDT, according to the USGS.

According to the Alaska Earthquake Center, the Aleutian megathrust is the primary cause of the strongest earthquakes in the region. The Aleutian megathrust is a major subduction zone fault, an area where two tectonic plates meet.

Closely monitored Barry Arm is a test case in a region where melting glaciers, steep slopes and narrow fjords set up conditions for dangerous tsunami-generating slides.