Alaska earthquakes

M3.9 earthquake 42 km WNW of Nikolski, Alaska

A magnitude 3.9 earthquake struck 42 km WNW of Nikolski, Alaska on Tue, Aug 10, 2021, 2:52 PM AKDT (22:52 UTC), 136 km (84 mi) below the surface.

A larger quake followed: M4.2 51 km SE of Nikolski, Alaska. This one was a foreshock.

Unalaska forecast More in Alaska

Map

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

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The earthquake

Magnitude: 3.9 (mb), minor
Local time: Tue, Aug 10, 2021, 2:52 PM AKDT
UTC: 2021-08-10 22:52:47 UTC
Depth: 135.8 km (84.4 mi), intermediate-depth
Epicenter: 53.026° N, 169.473° W
Region: Alaska
Tsunami flag: No
Status: Reviewed by a seismologist

Did you feel it?

No one has reported feeling this quake to the USGS.

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 10.4 km horizontally, 5.7 km in depth
Magnitude uncertainty: ±0.10
Depth from: From location
Station coverage gap: 134°
Stations used: 65

Nearest places

Distance and direction from each place to the epicenter, with its forecast.

Unalaska, AlaskaPopulation 4,491. Forecast216 kmWSW

Nearby

Within 100 km, magnitude 1.5 and up: 48 in the 60 days after this one and 25 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 us6000f8e3 (also filed as ak021a7ipu1e). Read Wed, Sep 23, 2026, 9:56 PM UTC.