Alaska earthquakes

M3.7 earthquake 261 km W of Adak, Alaska

A magnitude 3.7 earthquake struck 261 km W of Adak, Alaska on Fri, Apr 16, 2021, 11:41 PM GMT+12 (11:41 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M5.0 Rat Islands, Aleutian Islands, Alaska. This one was a foreshock.

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The earthquake

Magnitude: 3.7 (mb), minor
Local time: Fri, Apr 16, 2021, 11:41 PM GMT+12
UTC: 2021-04-16 11:41:09 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 52.152° N, 179.579° 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 5.8 km horizontally, 2.0 km in depth
Magnitude uncertainty: ±0.12
Depth from: Operator assigned
Station coverage gap: 182°, poorly surrounded by stations
Stations used: 47

Nearby

Within 100 km, magnitude 1.5 and up: 12 in the 60 days after this one and 6 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 us7000e14u (also filed as ak0214vhrehc). Read Sat, Sep 26, 2026, 3:27 AM UTC.