M4.9 earthquake 57 km SSE of Adak, Alaska

A magnitude 4.9 earthquake struck 57 km SSE of Adak, Alaska on Mon, Dec 15, 2025, 8:03 AM HAST (18:03 UTC), 42 km (26 mi) below the surface.

A larger quake followed: M5.3 39 km E 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
4.9	Mww, W-phase moment	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.073 · 18 stations
5.3	ML, local (Richter)	Alaska Earthquake Center	Reviewed · ±0.3 · 45 stations
5.0	Mwr, regional moment	USGS National Earthquake Information Center	Moment tensor · Reviewed

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

6 people reported to the USGS what they felt; the strongest reported shaking was III, weak shaking.

How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.

Reviewed by a seismologist.

Within 100 km, magnitude 1.9 and up: 142 in the 60 days after this one and 64 in the 30 days before it.

The first 60 of 142.

From the USGS Earthquake Hazards Program and its partner networks, event us6000rv18 (also filed as ak2025yqeqgg). Read Fri, Oct 2, 2026, 6:31 AM UTC.