Alaska earthquakes

M3.5 earthquake 24 km ESE of Unalaska, Alaska

A magnitude 3.5 earthquake struck 24 km ESE of Unalaska, Alaska on Wed, Aug 4, 2021, 4:35 PM AKDT (00:35 UTC), 86 km (53 mi) below the surface.

A larger quake followed: M3.6 38 km SE of Akutan, 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.

Open the live map with earthquakes

The earthquake

Magnitude: 3.5 (mb), minor
Local time: Wed, Aug 4, 2021, 4:35 PM AKDT
UTC: 2021-08-05 00:35:52 UTC
Depth: 85.7 km (53.3 mi), intermediate-depth
Epicenter: 53.781° N, 166.200° W
Region: Alaska
Tsunami flag: No
Status: Reviewed by a seismologist

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 5.8 km horizontally, 5.0 km in depth
Magnitude uncertainty: ±0.17
Depth from: From location
Station coverage gap: 172°
Stations used: 48

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast24 kmESE

Nearby

Within 100 km, magnitude 1.5 and up: 86 in the 60 days after this one and 53 in the 30 days before it.

After

The first 60 of 86.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us6000f5jx (also filed as ak0219yvtxbv). Read Wed, Sep 23, 2026, 5:31 AM UTC.