Alaska earthquakes

M3.9 earthquake 112 km ENE of Atka, Alaska

A magnitude 3.9 earthquake struck 112 km ENE of Atka, Alaska on Mon, Mar 15, 2021, 11:04 AM HADT (20:04 UTC), 211 km (131 mi) below the surface.

A larger quake followed: M4.2 76 km ESE of Atka, Alaska. This one was a foreshock.

Map

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The earthquake

Magnitude: 3.9 (mb), minor
Local time: Mon, Mar 15, 2021, 11:04 AM HADT
UTC: 2021-03-15 20:04:44 UTC
Depth: 211.3 km (131.3 mi), intermediate-depth
Epicenter: 52.729° N, 172.799° 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 13.1 km horizontally, 10.9 km in depth
Magnitude uncertainty: ±0.11
Depth from: From location
Station coverage gap: 152°
Stations used: 55

Nearby

Within 100 km, magnitude 1.5 and up: 26 in the 60 days after this one and 11 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 us6000dza5 (also filed as ak0213eppb01). Read Thu, Sep 24, 2026, 4:59 AM UTC.