Alaska earthquakes

M3.4 earthquake 200 km SSW of Adak, Alaska

A magnitude 3.4 earthquake struck 200 km SSW of Adak, Alaska on Thu, Aug 19, 2021, 6:03 PM HADT (03:03 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M4.5 161 km S of Adak, Alaska. This one was a foreshock.

Map

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

Open the live map with earthquakes

The earthquake

Magnitude: 3.4 (ml), minor
Local time: Thu, Aug 19, 2021, 6:03 PM HADT
UTC: 2021-08-20 03:03:35 UTC
Depth: 10.0 km (6.2 mi), shallow
Epicenter: 50.114° N, 177.270° 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 4.7 km horizontally, 2.0 km in depth
Magnitude uncertainty: ±0.12
Depth from: Operator assigned
Station coverage gap: 248°, poorly surrounded by stations
Stations used: 31

Nearby

Within 100 km, magnitude 1.5 and up: 15 in the 60 days after this one and 13 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 us7000f6kg (also filed as ak021anqhj89). Read Thu, Sep 24, 2026, 9:28 AM UTC.