M3.8 earthquake 42 km SSW of Adak, Alaska

A magnitude 3.8 earthquake struck 42 km SSW of Adak, Alaska on Fri, Dec 22, 2023, 8:42 PM HAST (06:42 UTC), 46 km (29 mi) below the surface.

A larger quake followed: M4.1 11 km SSE of Adak, 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
3.8	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.106 · 23 stations
3.8	ML, local (Richter)	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: 131 in the 60 days after this one and 120 in the 30 days before it.

The first 60 of 131.

From the USGS Earthquake Hazards Program and its partner networks, event us7000ll3w (also filed as ak023geiolm7). Read Thu, Oct 1, 2026, 8:14 AM UTC.