Alaska earthquakes

M3.9 earthquake 76 km SW of Nikolski, Alaska

A magnitude 3.9 earthquake struck 76 km SW of Nikolski, Alaska on Wed, Apr 7, 2021, 6:49 PM AKDT (02:49 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M4.9 128 km WSW 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: Wed, Apr 7, 2021, 6:49 PM AKDT
UTC: 2021-04-08 02:49:50 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 52.397° N, 169.547° 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 4.6 km horizontally, 2.0 km in depth
Magnitude uncertainty: ±0.26
Depth from: Operator assigned
Station coverage gap: 202°, poorly surrounded by stations
Stations used: 50

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast259 kmSW

Nearby

Within 100 km, magnitude 1.5 and up: 16 in the 60 days after this one and 33 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 us6000e1ts (also filed as ak0214i45hl6). Read Thu, Sep 24, 2026, 12:33 AM UTC.