Alaska earthquakes

M4.2 earthquake 145 km SE of Chignik, Alaska

A magnitude 4.2 earthquake struck 145 km SE of Chignik, Alaska on Thu, Jul 29, 2021, 12:15 AM AKDT (08:15 UTC), 18 km (11 mi) below the surface.

A larger quake followed: M6.9 125 km SE 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: 4.2 (ml), light
Local time: Thu, Jul 29, 2021, 12:15 AM AKDT
UTC: 2021-07-29 08:15:19 UTC
Depth: 18.4 km (11.4 mi), shallow
Epicenter: 55.316° N, 156.862° 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: 0.1% of gravity
Peak ground velocity: -3.3 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.

Stations used: 29

Nearest places

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

Sand Point, AlaskaPopulation 1,064. Forecast230 kmE

Nearby

Within 100 km, magnitude 1.5 and up: at least 201 in the 60 days after this one and 66 in the 30 days before it.

After

The first 60 of at least 201.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event ak0219nfpmy7 (also filed as us6000f06l). Read Thu, Sep 24, 2026, 1:24 PM UTC.