Alaska earthquakes

M3.4 earthquake 133 km WSW of Adak, Alaska

A magnitude 3.4 earthquake struck 133 km WSW of Adak, Alaska on Sun, Aug 22, 2021, 2:50 AM HADT (11:50 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M3.6 134 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: 3.4 (ml), minor
Local time: Sun, Aug 22, 2021, 2:50 AM HADT
UTC: 2021-08-22 11:50:05 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 51.283° N, 178.313° 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 4.3 km horizontally, 2.0 km in depth
Magnitude uncertainty: ±0.10
Depth from: Operator assigned
Station coverage gap: 204°, poorly surrounded by stations
Stations used: 33

Nearby

Within 100 km, magnitude 1.5 and up: 158 in the 60 days after this one and 41 in the 30 days before it.

After

The first 60 of 158.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000f7le (also filed as ak021ar6lpdt). Read Thu, Sep 24, 2026, 8:39 AM UTC.