Alaska earthquakes

M4.0 earthquake 186 km SSE of Unalaska, Alaska

A magnitude 4.0 earthquake struck 186 km SSE of Unalaska, Alaska on Tue, Feb 23, 2021, 1:33 PM AKST (22:33 UTC), 10 km (6 mi) below the surface.

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: 4.0 (mb), light
Local time: Tue, Feb 23, 2021, 1:33 PM AKST
UTC: 2021-02-23 22:33:40 UTC
Depth: 10.0 km (6.2 mi), shallow
Epicenter: 52.257° N, 165.824° 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 3.9 km horizontally, 2.0 km in depth
Magnitude uncertainty: ±0.10
Depth from: Operator assigned
Station coverage gap: 262°, poorly surrounded by stations
Stations used: 47

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast186 kmSSE

Nearby

Within 100 km, magnitude 1.5 and up: 15 in the 60 days after this one and 7 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 us6000dkih (also filed as ak0212hobfoy). Read Thu, Sep 24, 2026, 12:06 AM UTC.