Alaska earthquakes

M4.5 earthquake 147 km S of False Pass, Alaska

A magnitude 4.5 earthquake struck 147 km S of False Pass, Alaska on Thu, Sep 2, 2021, 7:55 PM AKDT (03:55 UTC), 12 km (8 mi) below the surface.

A larger quake followed: M5.1 154 km S of False Pass, Alaska. This one was a foreshock.

Akutan 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: 4.5 (mwr), light
Local time: Thu, Sep 2, 2021, 7:55 PM AKDT
UTC: 2021-09-03 03:55:45 UTC
Depth: 12.4 km (7.7 mi), shallow
Epicenter: 53.537° N, 163.602° W
Region: Alaska
Felt reports: 1
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: 0.1% of gravity
Peak ground velocity: -3.0 cm/s
Map: Automatic

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

Did you feel it?

1 person reported to the USGS what they felt; the strongest reported shaking was I, not felt shaking.

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: 4.5 Mwr
Nodal plane 1: Strike 175°, dip 35°, rake 28°
Nodal plane 2: Strike 61°, dip 74°, rake 122°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 4.5 km horizontally, 4.0 km in depth
Magnitude uncertainty: ±0.06
Depth from: From location
Station coverage gap: 122°
Stations used: 114

Nearest places

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

Akutan, AlaskaPopulation 1,040. Forecast157 kmESE

Nearby

Within 100 km, magnitude 1.5 and up: 113 in the 60 days after this one and 62 in the 30 days before it.

After

The first 60 of 113.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000f7bp (also filed as ak021bawbjy7). Read Wed, Sep 23, 2026, 4:27 AM UTC.