M3.9 earthquake 235 km WSW of Adak, Alaska

A magnitude 3.9 earthquake struck 235 km WSW of Adak, Alaska on Tue, Dec 19, 2023, 7:41 AM HAST (17:41 UTC), 46 km (29 mi) below the surface.

A larger quake followed: M4.3 180 km WSW 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
3.9	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.077 · 44 stations
3.5	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: 96 in the 60 days after this one and 31 in the 30 days before it.

The first 60 of 96.

From the USGS Earthquake Hazards Program and its partner networks, event us6000m1y6 (also filed as ak023g832rwx). Read Fri, Oct 2, 2026, 7:30 AM UTC.