M4.0 earthquake 114 km SE of Adak, Alaska

A magnitude 4.0 earthquake struck 114 km SE of Adak, Alaska on Fri, Dec 22, 2023, 2:45 AM HAST (12:45 UTC), 34 km (21 mi) below the surface.

A larger quake followed: M4.9 124 km SSW of Atka, 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
4.0	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.066 · 62 stations
4.0	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: 105 in the 60 days after this one and 60 in the 30 days before it.

The first 60 of 105.

From the USGS Earthquake Hazards Program and its partner networks, event us7000lkvu (also filed as ak023gcyqil6). Read Fri, Oct 2, 2026, 4:01 AM UTC.