Alaska earthquakes

M5.2 earthquake 69 km ESE of Nikolski, Alaska

A magnitude 5.2 earthquake struck 69 km ESE of Nikolski, Alaska on Thu, Nov 4, 2021, 12:57 AM AKDT (08:57 UTC), 39 km (24 mi) below the surface.

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: 5.2 (mww), moderate
Local time: Thu, Nov 4, 2021, 12:57 AM AKDT
UTC: 2021-11-04 08:57:06 UTC
Depth: 39.3 km (24.4 mi), shallow
Epicenter: 52.668° N, 167.932° W
Region: Alaska
Felt reports: 5
Strongest shaking: III, weak shaking
Tsunami flag: Yes: a large quake in an oceanic region
Status: Reviewed by a seismologist

Tsunami

The USGS flags a quake this large in an oceanic region. The flag does not mean a tsunami happened; the tsunami warning centers decide that, and their messages are below when they issued any.

Current tsunami warnings: tsunami.gov. Warnings in force in the US also appear on our alerts pages.

Shaking

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

Strongest estimated: III, weak shaking
Peak ground acceleration: 0.7% of gravity
Peak ground velocity: -0.9 cm/s
Map: Automatic

USGS ShakeMap: estimated shaking intensity around the epicenter — Estimated shaking intensity. Map: USGS ShakeMap.

Did you feel it?

5 people reported to the USGS what they felt; the strongest reported shaking was II, weak shaking.

Fault motion and ground failure

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

Faulting: Reverse (thrust)
Moment magnitude: 5.2 Mww
Nodal plane 1: Strike 332°, dip 37°, rake 116°
Nodal plane 2: Strike 121°, dip 57°, rake 72°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 5.0 km horizontally, 4.1 km in depth
Magnitude uncertainty: ±0.06
Depth from: From location
Station coverage gap: 43°
Stations used: 259

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast163 kmSW

Nearby

Within 100 km, magnitude 2.2 and up: 29 in the 60 days after this one and 20 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 us7000frcu (also filed as at00r21i75, usauto7000frcu, pt21308001, ak021e5imlf0, iscgem621262041). Read Mon, Sep 28, 2026, 6:22 PM UTC.