M4.0 earthquake 119 km WNW of Adak, Alaska

A magnitude 4.0 earthquake struck 119 km WNW of Adak, Alaska on Tue, Dec 19, 2023, 1:21 PM HAST (23:21 UTC), 221 km (138 mi) below the surface.

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 · ±0.122 · 18 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: 82 in the 60 days after this one and 69 in the 30 days before it.

The first 60 of 82.

From the USGS Earthquake Hazards Program and its partner networks, event us6000m175 (also filed as ak023g86j3sd). Read Thu, Oct 1, 2026, 5:12 PM UTC.