Alaska earthquakes

M5.5 earthquake 67 km SSW of Adak, Alaska

A magnitude 5.5 earthquake struck 67 km SSW of Adak, Alaska on Sat, Nov 22, 2025, 10:21 PM HAST (08:21 UTC), 33 km (21 mi) below the surface.

Map

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

Open the live map with earthquakes

The earthquake

Magnitude: 5.5 (Mww, W-phase moment), moderate
Magnitude from: USGS National Earthquake Information Center
Local time: Sat, Nov 22, 2025, 10:21 PM HAST
UTC: 2025-11-23 08:21:44 UTC
Depth: 33.0 km (20.5 mi), shallow
Epicenter: 51.311° N, 177.016° W
Region: Alaska
Felt reports: 3
Strongest shaking: IV, light shaking
PAGER alert: Green
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
5.5	Mww, W-phase moment	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.053 · 34 stations
5.8	ML, local (Richter)	Alaska Earthquake Center	Reviewed · ±0.3 · 60 stations
5.5	Mwr, regional moment	USGS National Earthquake Information Center	Moment tensor · Reviewed
5.4	Mwb, body-wave moment	USGS National Earthquake Information Center	Moment tensor · Reviewed
5.6	Mww, W-phase moment	USGS, automatic first solution	First automatic solution · Confirmed

Shaking

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

Strongest estimated: IV, light shaking
Peak ground acceleration: 4.2% of gravity
Peak ground velocity: 2.3 cm/s
Map: Automatic

USGS ShakeMap: estimated shaking intensity around the epicenter — Estimated shaking intensity. Map: USGS ShakeMap.

Did you feel it?

3 people reported to the USGS what they felt; the strongest reported shaking was IV, light shaking.

Estimated impact

The USGS PAGER system estimates deaths and economic losses from the shaking and the population and buildings exposed to it.

Alert level: Green: little or no damage or loss of life expected

Deaths: estimated chance of each range
Range	Chance
Under 1	69%
1 to 10	29%
10 to 100	2%
100 to 1,000	Under 1%
1,000 to 10,000	Under 1%
10,000 to 100,000	Under 1%
100,000 to 10,000,000	Under 1%

Economic losses: estimated chance of each range
Range, million USD	Chance
Under 1	65%
1 to 10	30%
10 to 100	4%
100 to 1,000	Under 1%
1,000 to 10,000	Under 1%
10,000 to 100,000	Under 1%
100,000 to 10,000,000	Under 1%

Aftershock forecast

The chance of at least one aftershock this large or larger, from the USGS operational aftershock forecast, issued Sun, Sep 27, 2026, 8:21 AM UTC. The USGS updates it as the sequence unfolds.

Within	M3+	M4+	M5+	M6+	M7+
1 day	Under 1%	Under 1%	Under 1%	Under 1%	Under 1%
1 week	5%	Under 1%	Under 1%	Under 1%	Under 1%
1 month	18%	2%	Under 1%	Under 1%	Under 1%
1 year	78%	16%	2%	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: 5.5 Mww
Nodal plane 1: Strike 287°, dip 33°, rake 131°
Nodal plane 2: Strike 61°, dip 66°, rake 67°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 3.8 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.05
Depth from: From modeling of broad-band P waveforms
Station coverage gap: 92°
Stations used: 115

Nearby

Within 100 km, magnitude 2.5 and up: 74 in the 60 days after this one and 16 in the 30 days before it.

After

The first 60 of 74.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us6000rpxa (also filed as ak2025xbbjhg, usauto6000rpxa). Read Fri, Oct 2, 2026, 12:00 PM UTC.