Alaska earthquakes

M3.9 earthquake 222 km WSW of Adak, Alaska

A magnitude 3.9 earthquake struck 222 km WSW of Adak, Alaska on Sun, Feb 21, 2021, 10:48 PM HAST (08:48 UTC), 22 km (14 mi) below the surface.

A larger quake followed: M5.4 185 km WSW of Adak, Alaska. This one was a foreshock.

Map

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The earthquake

Magnitude: 3.9 (mb), minor
Local time: Sun, Feb 21, 2021, 10:48 PM HAST
UTC: 2021-02-22 08:48:06 UTC
Depth: 22.0 km (13.7 mi), shallow
Epicenter: 50.933° N, 179.461° 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 6.0 km horizontally, 6.6 km in depth
Magnitude uncertainty: ±0.07
Depth from: From location
Station coverage gap: 228°, poorly surrounded by stations
Stations used: 110

Nearby

Within 100 km, magnitude 1.5 and up: 48 in the 60 days after this one and 46 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 us6000dk45 (also filed as ak0212fsj62i). Read Fri, Sep 25, 2026, 7:54 AM UTC.