Alaska earthquakes

M5.1 earthquake 79 km SE of Atka, Alaska

A magnitude 5.1 earthquake struck 79 km SE of Atka, Alaska on Mon, Dec 1, 2025, 12:21 PM HAST (22:21 UTC), 35 km (22 mi) below the surface.

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Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 5.1 (Mww, W-phase moment), moderate
Magnitude from: USGS National Earthquake Information Center
Local time: Mon, Dec 1, 2025, 12:21 PM HAST
UTC: 2025-12-01 22:21:07 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 51.648° N, 173.459° W
Region: Alaska
Felt reports: 2
Tsunami flag: No
Status: Reviewed by a seismologist

Magnitude estimates

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
5.1	Mww, W-phase moment	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.071 · 19 stations
5.0	ML, local (Richter)	Alaska Earthquake Center	Reviewed · ±0.28121952463827316 · 42 stations
4.9	Mwr, regional moment	USGS National Earthquake Information Center	Moment tensor · Reviewed
5.1	Mww, W-phase moment	USGS, automatic first solution	First automatic solution · Confirmed

Did you feel it?

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

Aftershock forecast

The chance of at least one aftershock this large or larger, from the USGS operational aftershock forecast, issued Mon, Sep 28, 2026, 10:21 PM UTC. The USGS updates it as the sequence unfolds.

Within	M3+	M4+	M5+	M6+	M7+
1 day	1%	Under 1%	Under 1%	Under 1%	Under 1%
1 week	9%	Under 1%	Under 1%	Under 1%	Under 1%
1 month	32%	4%	Under 1%	Under 1%	Under 1%
1 year	94%	29%	3%	Under 1%	Under 1%

In the coming week the USGS expects about 0 aftershocks of magnitude 3 or more, and most likely between 0 and 1.

Fault motion and ground failure

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

Faulting: Oblique reverse
Moment magnitude: 5.1 Mww
Nodal plane 1: Strike 355°, dip 81°, rake 49°
Nodal plane 2: Strike 254°, dip 41°, rake 166°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 3.1 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.07
Depth from: Operator assigned
Station coverage gap: 106°
Stations used: 95

Nearby

Within 100 km, magnitude 2.1 and up: 29 in the 60 days after this one and 8 in the 30 days before it.

After

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000rez4 (also filed as ak2025xquzsz, usauto7000rez4). Read Fri, Oct 2, 2026, 4:11 PM UTC.