Alaska earthquakes

M3.3 earthquake 42 km SSE of Nikolski, Alaska

A magnitude 3.3 earthquake struck 42 km SSE of Nikolski, Alaska on Mon, Oct 18, 2021, 8:17 AM AKDT (16:17 UTC), 40 km (25 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: 3.3 (ml), minor
Local time: Mon, Oct 18, 2021, 8:17 AM AKDT
UTC: 2021-10-18 16:17:12 UTC
Depth: 39.8 km (24.7 mi), shallow
Epicenter: 52.593° N, 168.601° 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 12.8 km horizontally, 27.5 km in depth
Magnitude uncertainty: ±0.12
Depth from: From location
Station coverage gap: 281°, poorly surrounded by stations
Stations used: 24

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast198 kmSW

Nearby

Within 100 km, magnitude 1.5 and up: 50 in the 60 days after this one and 18 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 us6000g9tl (also filed as ak021ddj0lq3). Read Mon, Sep 28, 2026, 1:28 PM UTC.