Alaska earthquakes

M4.8 earthquake 190 km SW of Nikolski, Alaska

A magnitude 4.8 earthquake struck 190 km SW of Nikolski, Alaska on Thu, Sep 30, 2021, 3:24 PM HADT (00:24 UTC), 35 km (22 mi) below the surface.

Map

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The earthquake

Magnitude: 4.8 (mb), light
Local time: Thu, Sep 30, 2021, 3:24 PM HADT
UTC: 2021-10-01 00:24:39 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 51.946° N, 171.139° W
Region: Alaska
Strongest shaking: II, 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: II, weak shaking
Peak ground acceleration: 0.3% of gravity
Peak ground velocity: -2.0 cm/s
Map: Automatic

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

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 6.3 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.03
Depth from: Operator assigned
Station coverage gap: 125°
Stations used: 102

Nearby

Within 100 km, magnitude 1.8 and up: 12 in the 60 days after this one and 8 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 us6000fqm1 (also filed as ak021cl5egfw). Read Sun, Sep 27, 2026, 4:01 AM UTC.