Alaska earthquakes

M3.1 earthquake 113 km SW of Nikolski, Alaska

A magnitude 3.1 earthquake struck 113 km SW of Nikolski, Alaska on Mon, Sep 20, 2021, 8:53 PM HADT (05:53 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M5.2 185 km SW of Nikolski, Alaska. This one was a foreshock.

Unalaska forecast More in Alaska

Map

Where this earthquake was located, with the others nearby. Select one for its page.

Open the live map with earthquakes

The earthquake

Magnitude: 3.1 (ml), minor
Local time: Mon, Sep 20, 2021, 8:53 PM HADT
UTC: 2021-09-21 05:53:21 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 52.181° N, 169.972° 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 3.7 km horizontally, 2.0 km in depth
Magnitude uncertainty: ±0.10
Depth from: Operator assigned
Station coverage gap: 217°, poorly surrounded by stations
Stations used: 22

Nearest places

Distance and direction from each place to the epicenter, with its forecast.

Unalaska, AlaskaPopulation 4,491. Forecast297 kmSW

Nearby

Within 100 km, magnitude 1.5 and up: 27 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 us6000fvzn (also filed as ak021c4p66yf). Read Sat, Sep 26, 2026, 4:03 PM UTC.