M4.6 earthquake 80 km SSW of Unalaska, Alaska

A magnitude 4.6 earthquake struck 80 km SSW of Unalaska, Alaska on Thu, Mar 5, 1987, 9:20 AM AKST (18:20 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M5.4 74 km SW of Unalaska, Alaska. This one was a foreshock.

Map

Where this earthquake was located, with the others nearby. Select one for its page.

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Distance and direction from each place to the epicenter, with its forecast.

Within 100 km, magnitude 1.6 and up: 23 in the 60 days after this one and 21 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event usp000330d. Read Tue, Sep 22, 2026, 11:33 AM UTC.