Alaska earthquakes

M3.9 earthquake 173 km S of Nikolski, Alaska

A magnitude 3.9 earthquake struck 173 km S of Nikolski, Alaska on Fri, Jul 31, 2020, 11:47 AM AKDT (19:47 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M5.5 129 km SSW of Nikolski, Alaska. This one was a foreshock.

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The earthquake

Magnitude: 3.9 (mb), minor
Local time: Fri, Jul 31, 2020, 11:47 AM AKDT
UTC: 2020-07-31 19:47:58 UTC
Depth: 10.0 km (6.2 mi), shallow
Epicenter: 51.385° N, 168.617° 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 6.2 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.06
Depth from: Operator assigned
Station coverage gap: 140°
Stations used: 142

Nearby

Within 100 km, magnitude 1.5 and up: 29 in the 60 days after this one and 15 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 us6000b7ls (also filed as ak0209sl2g97). Read Wed, Sep 30, 2026, 12:49 PM UTC.