M4.2 earthquake 31 km WSW of Unalaska, Alaska

A magnitude 4.2 earthquake struck 31 km WSW of Unalaska, Alaska on Tue, Mar 3, 1987, 5:22 PM AKST (02:22 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 1.5 and up: 22 in the 60 days after this one and 20 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event usp00032z4. Read Wed, Sep 30, 2026, 4:27 AM UTC.