M2.5 earthquake 66 km WSW of Atka, Alaska

A magnitude 2.5 earthquake struck 66 km WSW of Atka, Alaska on Wed, Dec 20, 2023, 5:29 PM HAST (03:29 UTC), 81 km (50 mi) below the surface.

A larger quake followed: M6.1 116 km SE 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
2.5	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.115 · 10 stations
2.3	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: 138 in the 60 days after this one and 52 in the 30 days before it.

The first 60 of 138.

From the USGS Earthquake Hazards Program and its partner networks, event us6000m23c (also filed as ak023gb5qrbt). Read Thu, Oct 1, 2026, 9:11 PM UTC.