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.

ANCHORAGE, Alaska (KTUU) - Heavy rain in the Portage Valley is raising the concern of a possible landslide into Portage Lake. An announcement was made by the U.S. Forest Service on the Chugach National Forest’s Facebook page.