Alaska earthquakes

M3.9 earthquake 246 km WSW of Adak, Alaska

A magnitude 3.9 earthquake struck 246 km WSW of Adak, Alaska on Wed, Oct 6, 2021, 11:56 AM GMT-12 (23:56 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M5.2 280 km WSW of Adak, Alaska. This one was a foreshock.

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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, Oct 6, 2021, 11:56 AM GMT-12
UTC: 2021-10-06 23:56:41 UTC
Depth: 10.0 km (6.2 mi), shallow
Epicenter: 51.015° N, 179.895° 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 2.5 km horizontally, 2.0 km in depth
Magnitude uncertainty: ±0.09
Depth from: Operator assigned
Station coverage gap: 230°, poorly surrounded by stations
Stations used: 56

Nearby

Within 100 km, magnitude 1.5 and up: 88 in the 60 days after this one and 48 in the 30 days before it.

After

The first 60 of 88.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us6000ftz8 (also filed as ak021ctsyw59). Read Fri, Sep 25, 2026, 11:44 PM UTC.