Alaska earthquakes

M3.9 earthquake 71 km NE of Adak, Alaska

A magnitude 3.9 earthquake struck 71 km NE of Adak, Alaska on Mon, Aug 17, 2020, 11:19 PM HADT (08:19 UTC), 154 km (96 mi) below the surface.

A larger quake followed: M5.3 76 km SW of Atka, Alaska. This one was a foreshock.

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The earthquake

Magnitude: 3.9 (mb), minor
Local time: Mon, Aug 17, 2020, 11:19 PM HADT
UTC: 2020-08-18 08:19:06 UTC
Depth: 153.8 km (95.6 mi), intermediate-depth
Epicenter: 52.296° N, 175.846° 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 11.0 km horizontally, 5.5 km in depth
Magnitude uncertainty: ±0.21
Depth from: From location
Station coverage gap: 94°
Stations used: 45

Nearby

Within 100 km, magnitude 1.5 and up: 105 in the 60 days after this one and 52 in the 30 days before it.

After

The first 60 of 105.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000bclu (also filed as ak020am60q4c). Read Tue, Sep 29, 2026, 3:59 PM UTC.