Alaska earthquakes

M4.0 earthquake 235 km WSW of Adak, Alaska

A magnitude 4.0 earthquake struck 235 km WSW of Adak, Alaska on Tue, Sep 1, 2020, 6:00 PM HADT (03:00 UTC), 19 km (12 mi) below the surface.

A larger quake followed: M4.8 193 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: 4.0 (mb), light
Local time: Tue, Sep 1, 2020, 6:00 PM HADT
UTC: 2020-09-02 03:00:22 UTC
Depth: 19.1 km (11.9 mi), shallow
Epicenter: 51.285° N, 179.891° 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, 4.7 km in depth
Magnitude uncertainty: ±0.13
Depth from: From location
Station coverage gap: 141°
Stations used: 80

Nearby

Within 100 km, magnitude 1.5 and up: 137 in the 60 days after this one and 71 in the 30 days before it.

After

The first 60 of 137.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000bgh0 (also filed as ak020bavzq0t). Read Mon, Sep 28, 2026, 3:01 PM UTC.