Alaska earthquakes

M3.8 earthquake 106 km SW of Nikolski, Alaska

A magnitude 3.8 earthquake struck 106 km SW of Nikolski, Alaska on Tue, Jul 13, 2021, 12:29 PM AKDT (20:29 UTC), 44 km (28 mi) below the surface.

A larger quake followed: M4.2 74 km WNW of Nikolski, Alaska. This one was a foreshock.

Unalaska 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: 3.8 (mb), minor
Local time: Tue, Jul 13, 2021, 12:29 PM AKDT
UTC: 2021-07-13 20:29:57 UTC
Depth: 44.5 km (27.6 mi), shallow
Epicenter: 52.258° N, 169.963° 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: -3.0 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 6.5 km horizontally, 8.3 km in depth
Magnitude uncertainty: ±0.07
Depth from: From location
Station coverage gap: 138°
Stations used: 124

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast291 kmSW

Nearby

Within 100 km, magnitude 1.5 and up: 57 in the 60 days after this one and 9 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 us7000elpb (also filed as ak0218x6cc4s). Read Mon, Sep 28, 2026, 4:59 AM UTC.