The giant earthquake was recorded at 12:37 p.m. local time, southeast of Sand Point, a community located on Popof Island in the Aleutian Chain.

A tsunami warning that was later downgraded was issued for several coastal communities after the earthquake struck south of Sand Point.

Tsunamis are a series of long waves caused by a large and sudden displacement of water in the ocean, usually from a large earthquake on or below the ocean floor. Tsunamis radiate in all directions from the epicenter and can cause dangerous coastal flooding and powerful currents that can last for hours or days.