Alaska earthquakes

M4.0 earthquake 99 km SE of Atka, Alaska

A magnitude 4.0 earthquake struck 99 km SE of Atka, Alaska on Sat, May 22, 2021, 4:57 AM HADT (13:57 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M4.2 45 km E of Atka, Alaska. This one was a foreshock.

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The earthquake

Magnitude: 4.0 (mb), light
Local time: Sat, May 22, 2021, 4:57 AM HADT
UTC: 2021-05-22 13:57:14 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 51.517° N, 173.258° 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 2.7 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.12
Depth from: Operator assigned
Station coverage gap: 132°
Stations used: 58

Nearby

Within 100 km, magnitude 1.5 and up: 47 in the 60 days after this one and 22 in the 30 days before it.

After

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000e5b4 (also filed as ak0216j2e6eo). Read Thu, Sep 24, 2026, 5:40 AM UTC.