Alaska earthquakes

M5.1 earthquake 95 km SSE of Perryville, Alaska

A magnitude 5.1 earthquake struck 95 km SSE of Perryville, Alaska on Thu, Oct 28, 2021, 11:06 AM AKDT (19:06 UTC), 28 km (17 mi) below the surface.

A larger quake followed: M5.6 115 km SSE of Perryville, Alaska. This one was a foreshock.

Sand Point 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: 5.1 (mww), moderate
Local time: Thu, Oct 28, 2021, 11:06 AM AKDT
UTC: 2021-10-28 19:06:56 UTC
Depth: 28.0 km (17.4 mi), shallow
Epicenter: 55.073° N, 158.837° W
Region: Alaska
Felt reports: 3
Strongest shaking: IV, light 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: IV, light shaking
Peak ground acceleration: 1.5% of gravity
Peak ground velocity: -0.2 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 IV, light 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: 5.1 Mww
Nodal plane 1: Strike 245°, dip 23°, rake 92°
Nodal plane 2: Strike 63°, dip 67°, rake 89°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 3.4 km horizontally, 3.9 km in depth
Magnitude uncertainty: ±0.04
Depth from: From location
Station coverage gap: 63°
Stations used: 197

Nearest places

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

Sand Point, AlaskaPopulation 1,064. Forecast110 kmESE

Nearby

Within 100 km, magnitude 2.1 and up: 129 in the 60 days after this one and 59 in the 30 days before it.

After

The first 60 of 129.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000fphz (also filed as iscgem622506045, ak021du443s4). Read Sat, Sep 26, 2026, 5:02 PM UTC.