Alaska earthquakes

M4.0 earthquake 26 km NNW of Atka, Alaska

A magnitude 4.0 earthquake struck 26 km NNW of Atka, Alaska on Tue, Sep 22, 2020, 4:17 PM HADT (01:17 UTC), 122 km (76 mi) below the surface.

A larger quake followed: M5.3 76 km SW of Atka, 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: 4.0 (mb), light
Local time: Tue, Sep 22, 2020, 4:17 PM HADT
UTC: 2020-09-23 01:17:23 UTC
Depth: 122.0 km (75.8 mi), intermediate-depth
Epicenter: 52.407° N, 174.379° 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 9.3 km horizontally, 4.5 km in depth
Magnitude uncertainty: ±0.13
Depth from: From location
Station coverage gap: 95°
Stations used: 58

Nearby

Within 100 km, magnitude 1.5 and up: 70 in the 60 days after this one and 37 in the 30 days before it.

After

The first 60 of 70.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us6000c2j2 (also filed as ak020c9l6sn8). Read Mon, Sep 28, 2026, 3:03 AM UTC.