Alaska earthquakes

M3.9 earthquake 270 km W of Adak, Alaska

A magnitude 3.9 earthquake struck 270 km W of Adak, Alaska on Thu, Apr 23, 2020, 5:13 AM GMT+12 (17:13 UTC), 111 km (69 mi) below the surface.

A larger quake followed: M4.3 211 km W 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: 3.9 (mb), minor
Local time: Thu, Apr 23, 2020, 5:13 AM GMT+12
UTC: 2020-04-22 17:13:12 UTC
Depth: 111.3 km (69.1 mi), intermediate-depth
Epicenter: 51.571° N, 179.477° E
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 9.6 km horizontally, 6.1 km in depth
Magnitude uncertainty: ±0.06
Depth from: From location
Station coverage gap: 120°
Stations used: 61

Nearby

Within 100 km, magnitude 1.5 and up: 110 in the 60 days after this one and 55 in the 30 days before it.

After

The first 60 of 110.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us700091vb (also filed as ak020575xeg9). Read Tue, Sep 29, 2026, 9:53 PM UTC.