Alaska earthquakes

M4.8 earthquake 54 km W of Adak, Alaska

A magnitude 4.8 earthquake struck 54 km W of Adak, Alaska on Tue, Aug 5, 2025, 2:04 AM HADT (11:04 UTC), 87 km (54 mi) below the surface.

A larger quake followed: M5.5 122 km SW 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: 4.8 (Mww, W-phase moment), light
Magnitude from: USGS National Earthquake Information Center
Local time: Tue, Aug 5, 2025, 2:04 AM HADT
UTC: 2025-08-05 11:04:08 UTC
Depth: 86.5 km (53.8 mi), intermediate-depth
Epicenter: 51.875° N, 177.430° W
Region: Alaska
Felt reports: 4
Strongest shaking: III, weak 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
4.8	Mww, W-phase moment	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.069 · 20 stations
4.8	Mww, W-phase moment	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: III, weak shaking
Peak ground acceleration: 0.1% 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?

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

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 6.8 km horizontally, 3.3 km in depth
Magnitude uncertainty: ±0.07
Depth from: From location
Station coverage gap: 81°
Stations used: 138

Nearby

Within 100 km, magnitude 1.8 and up: 78 in the 60 days after this one and 91 in the 30 days before it.

After

The first 60 of 78.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us6000qy8a (also filed as ak0259z26yop). Read Fri, Oct 2, 2026, 11:43 AM UTC.