M3.9 earthquake 252 km W of Adak, Alaska

A magnitude 3.9 earthquake struck 252 km W of Adak, Alaska on Wed, Aug 31, 2022, 5:29 PM GMT+12 (05:29 UTC), 135 km (84 mi) below the surface.

A larger quake followed: M5.0 Rat Islands, Aleutian Islands, Alaska. This one was a foreshock.

Map

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

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
3.9	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.064 · 64 stations
3.9	mb, body-wave	Alaska Earthquake Center	Preliminary

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Within 100 km, magnitude 1.5 and up: 101 in the 60 days after this one and 63 in the 30 days before it.

The first 60 of 101.

From the USGS Earthquake Hazards Program and its partner networks, event us7000i3x4 (also filed as ak022b5yqszm). Read Fri, Oct 2, 2026, 6:04 PM UTC.