Alaska earthquakes

M3.9 earthquake 249 km WSW of Adak, Alaska

A magnitude 3.9 earthquake struck 249 km WSW of Adak, Alaska on Thu, Apr 9, 2020, 6:18 AM GMT-12 (18:18 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M4.3 211 km W of Adak, Alaska. This one was a foreshock.

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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 9, 2020, 6:18 AM GMT-12
UTC: 2020-04-09 18:18:00 UTC
Depth: 10.0 km (6.2 mi), shallow
Epicenter: 50.961° N, 179.914° 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 3.9 km horizontally, 1.7 km in depth
Magnitude uncertainty: ±0.07
Depth from: Operator assigned
Station coverage gap: 195°, poorly surrounded by stations
Stations used: 74

Nearby

Within 100 km, magnitude 1.5 and up: 89 in the 60 days after this one and 46 in the 30 days before it.

After

The first 60 of 89.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us70008sky (also filed as ak0204lokdf8). Read Wed, Sep 30, 2026, 12:40 AM UTC.