Alaska earthquakes

M4.4 earthquake 39 km ESE of Nikolski, Alaska

A magnitude 4.4 earthquake struck 39 km ESE of Nikolski, Alaska on Thu, Sep 23, 2021, 2:41 PM AKDT (22:41 UTC), 39 km (24 mi) below the surface.

A larger quake followed: M5.2 69 km ESE 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.

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The earthquake

Magnitude: 4.4 (mwr), light
Local time: Thu, Sep 23, 2021, 2:41 PM AKDT
UTC: 2021-09-23 22:41:10 UTC
Depth: 39.2 km (24.4 mi), shallow
Epicenter: 52.751° N, 168.365° 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.

Fault motion and ground failure

How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.

Faulting: Strike-slip
Moment magnitude: 4.4 Mwr
Nodal plane 1: Strike 353°, dip 41°, rake 165°
Nodal plane 2: Strike 94°, dip 80°, rake 50°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 6.1 km horizontally, 5.9 km in depth
Magnitude uncertainty: ±0.07
Depth from: From location
Station coverage gap: 139°
Stations used: 105

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast174 kmSW

Nearby

Within 100 km, magnitude 1.5 and up: 57 in the 60 days after this one and 30 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 us7000fdwu (also filed as ak021c8aant0). Read Sun, Sep 27, 2026, 10:11 AM UTC.