Alaska earthquakes

M3.7 earthquake 47 km NE of Adak, Alaska

A magnitude 3.7 earthquake struck 47 km NE of Adak, Alaska on Wed, Oct 27, 2021, 11:20 PM HADT (08:20 UTC), 188 km (117 mi) below the surface.

A larger quake followed: M4.0 29 km SSW of Adak, Alaska. This one was a foreshock.

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The earthquake

Magnitude: 3.7 (mb), minor
Local time: Wed, Oct 27, 2021, 11:20 PM HADT
UTC: 2021-10-28 08:20:26 UTC
Depth: 187.6 km (116.6 mi), intermediate-depth
Epicenter: 52.138° N, 176.096° 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 13.5 km horizontally, 4.0 km in depth
Magnitude uncertainty: ±0.21
Depth from: From location
Station coverage gap: 128°
Stations used: 36

Nearby

Within 100 km, magnitude 1.5 and up: 115 in the 60 days after this one and 42 in the 30 days before it.

After

The first 60 of 115.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us6000g9rh (also filed as ak021dtxn9x7). Read Thu, Sep 24, 2026, 10:09 AM UTC.