Alaska earthquakes

M4.0 earthquake 95 km SSE of Adak, Alaska

A magnitude 4.0 earthquake struck 95 km SSE of Adak, Alaska on Wed, Sep 24, 2025, 12:21 PM HADT (21:21 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M5.5 67 km SSW of Adak, Alaska. This one was a foreshock.

Map

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

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The earthquake

Magnitude: 4.0 (mb, body-wave), light
Magnitude from: USGS National Earthquake Information Center
Local time: Wed, Sep 24, 2025, 12:21 PM HADT
UTC: 2025-09-24 21:21:14 UTC
Depth: 10.0 km (6.2 mi), shallow
Epicenter: 51.118° N, 175.995° W
Region: Alaska
Felt reports: 1
Strongest shaking: I, not felt shaking
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
4.0	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.108 · 23 stations
3.6	ML, local (Richter)	Alaska Earthquake Center	Preliminary

Shaking

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

Strongest estimated: I, not felt shaking
Peak ground acceleration: 0.0% of gravity
Peak ground velocity: 0.0 cm/s
Map: Automatic

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

Did you feel it?

1 person reported to the USGS what they felt; the strongest reported shaking was I, not felt shaking.

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 4.6 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.11
Depth from: Operator assigned
Station coverage gap: 203°, poorly surrounded by stations
Stations used: 42

Nearby

Within 100 km, magnitude 1.5 and up: 32 in the 60 days after this one and 31 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 us6000rcpy (also filed as ak025c9x4avl). Read Sat, Oct 3, 2026, 12:04 AM UTC.