Alaska earthquakes

M4.0 earthquake 247 km ESE of Chiniak, Alaska

A magnitude 4.0 earthquake struck 247 km ESE of Chiniak, Alaska on Mon, Aug 23, 2021, 11:28 AM AKDT (19:28 UTC), 10 km (6 mi) below the surface.

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Map

Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 4.0 (mb), light
Local time: Mon, Aug 23, 2021, 11:28 AM AKDT
UTC: 2021-08-23 19:28:50 UTC
Depth: 10.0 km (6.2 mi), shallow
Epicenter: 56.443° N, 148.820° W
Region: Alaska
Strongest shaking: I, not felt 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: I, not felt shaking
Peak ground acceleration: 0.0% of gravity
Peak ground velocity: -6.9 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 2.8 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.20
Depth from: Operator assigned
Station coverage gap: 80°
Stations used: 84

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 31 in the 60 days after this one and 14 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 us7000f2rj (also filed as ak021asyrwka). Read Thu, Sep 24, 2026, 12:07 AM UTC.