Alaska earthquakes

M3.6 earthquake 262 km W of Adak, Alaska

A magnitude 3.6 earthquake struck 262 km W of Adak, Alaska on Fri, Aug 20, 2021, 6:10 PM GMT+12 (06:10 UTC), 80 km (49 mi) below the surface.

A larger quake followed: M4.0 257 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: 3.6 (ml), minor
Local time: Fri, Aug 20, 2021, 6:10 PM GMT+12
UTC: 2021-08-20 06:10:38 UTC
Depth: 79.7 km (49.5 mi), intermediate-depth
Epicenter: 51.645° N, 179.580° 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 10.1 km horizontally, 10.5 km in depth
Magnitude uncertainty: ±0.09
Depth from: From location
Station coverage gap: 119°
Stations used: 47

Nearby

Within 100 km, magnitude 1.5 and up: 102 in the 60 days after this one and 80 in the 30 days before it.

After

The first 60 of 102.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000f6kh (also filed as ak021ansbccb). Read Fri, Sep 25, 2026, 10:54 PM UTC.