M3.8 earthquake 55 km NW of Atka, Alaska

A magnitude 3.8 earthquake struck 55 km NW of Atka, Alaska on Mon, Dec 18, 2023, 5:11 AM HAST (15:11 UTC), 193 km (120 mi) below the surface.

A larger quake followed: M4.2 50 km NNW 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
3.8	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.086 · 35 stations
3.2	ML, local (Richter)	Alaska Earthquake Center	Preliminary

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Within 100 km, magnitude 1.5 and up: 53 in the 60 days after this one and 31 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event us6000m155 (also filed as ak023g6e63o6). Read Thu, Oct 1, 2026, 4:42 AM UTC.