M3.9 earthquake 105 km SW of Adak, Alaska

A magnitude 3.9 earthquake struck 105 km SW of Adak, Alaska on Mon, Dec 1, 2025, 12:29 AM HAST (10:29 UTC), 48 km (30 mi) below the surface.

A larger quake followed: M4.9 57 km SSE 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 · ±0.148 · 12 stations
4.06	ML, local (Richter)	Alaska Earthquake Center	Reviewed · ±0.2408365766640009 · 19 stations

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Within 100 km, magnitude 1.5 and up: 126 in the 60 days after this one and 40 in the 30 days before it.

The first 60 of 126.

From the USGS Earthquake Hazards Program and its partner networks, event us7000rewa (also filed as ak2025xpxkax). Read Fri, Oct 2, 2026, 4:44 AM UTC.