Alaska earthquakes

M2.8 earthquake 220 km WSW of Adak, Alaska

A magnitude 2.8 earthquake struck 220 km WSW of Adak, Alaska on Mon, Sep 20, 2021, 3:56 AM HADT (12:56 UTC), 22 km (14 mi) below the surface.

A larger quake followed: M4.0 257 km WSW of Adak, Alaska. This one was a foreshock.

Map

Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 2.8 (ml), micro
Local time: Mon, Sep 20, 2021, 3:56 AM HADT
UTC: 2021-09-20 12:56:14 UTC
Depth: 21.9 km (13.6 mi), shallow
Epicenter: 51.061° N, 179.523° 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 3.4 km horizontally, 11.2 km in depth
Magnitude uncertainty: ±0.10
Depth from: From location
Station coverage gap: 227°, poorly surrounded by stations
Stations used: 24

Nearby

Within 100 km, magnitude 1.5 and up: 103 in the 60 days after this one and 72 in the 30 days before it.

After

The first 60 of 103.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us6000fv3e (also filed as ak021c35tig2). Read Thu, Sep 24, 2026, 9:43 AM UTC.