Alaska earthquakes

M5.2 earthquake 185 km SW of Nikolski, Alaska

A magnitude 5.2 earthquake struck 185 km SW of Nikolski, Alaska on Thu, Sep 30, 2021, 3:10 PM HADT (00:10 UTC), 35 km (22 mi) below the surface.

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, Sep 30, 2021, 3:10 PM HADT
UTC: 2021-10-01 00:10:52 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 51.983° N, 171.100° W
Region: Alaska
Felt reports: 3
Strongest shaking: III, weak shaking
Tsunami flag: No
Status: Reviewed by a seismologist

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: -1.2 cm/s
Map: Automatic

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

Did you feel it?

3 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 269°, dip 36°, rake 90°
Nodal plane 2: Strike 90°, dip 54°, rake 90°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 6.1 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.06
Depth from: Operator assigned
Station coverage gap: 87°
Stations used: 125

Nearby

Within 100 km, magnitude 2.2 and up: 13 in the 60 days after this one and 7 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 us6000fqlv (also filed as ak021cl5bcb0, iscgem621113751). Read Sun, Sep 27, 2026, 10:46 AM UTC.