Alaska earthquakes

M3.1 earthquake 135 km WSW of Adak, Alaska

A magnitude 3.1 earthquake struck 135 km WSW of Adak, Alaska on Wed, Sep 29, 2021, 12:55 AM HADT (09:55 UTC), 30 km (18 mi) below the surface.

A larger quake followed: M3.9 116 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: 3.1 (ml), minor
Local time: Wed, Sep 29, 2021, 12:55 AM HADT
UTC: 2021-09-29 09:55:15 UTC
Depth: 29.7 km (18.4 mi), shallow
Epicenter: 51.213° N, 178.271° 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 4.0 km horizontally, 5.9 km in depth
Magnitude uncertainty: ±0.10
Depth from: From location
Station coverage gap: 214°, poorly surrounded by stations
Stations used: 34

Nearby

Within 100 km, magnitude 1.5 and up: 140 in the 60 days after this one and 59 in the 30 days before it.

After

The first 60 of 140.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000fpkc (also filed as ak021chzv4as). Read Thu, Sep 24, 2026, 7:28 AM UTC.