Alaska earthquakes

M3.4 earthquake 237 km W of Adak, Alaska

A magnitude 3.4 earthquake struck 237 km W of Adak, Alaska on Mon, Dec 20, 2021, 5:26 PM HAST (03:26 UTC), 28 km (18 mi) below the surface.

A larger quake followed: M5.1 Andreanof Islands, Aleutian Islands, Alaska. This one was a foreshock.

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The earthquake

Magnitude: 3.4 (ml), minor
Local time: Mon, Dec 20, 2021, 5:26 PM HAST
UTC: 2021-12-21 03:26:46 UTC
Depth: 28.4 km (17.7 mi), shallow
Epicenter: 51.711° N, 179.936° E
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 2.2 km horizontally, 10.0 km in depth
Magnitude uncertainty: ±0.13
Depth from: From location
Station coverage gap: 129°
Stations used: 33

Nearby

Within 100 km, magnitude 1.5 and up: 92 in the 60 days after this one and 45 in the 30 days before it.

After

The first 60 of 92.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000gchk (also filed as ak021gb5q6bp). Read Sat, Sep 26, 2026, 5:41 AM UTC.