Alaska earthquakes

M2.7 earthquake 77 km SE of Atka, Alaska

A magnitude 2.7 earthquake struck 77 km SE of Atka, Alaska on Mon, Sep 20, 2021, 10:12 AM HADT (19:12 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M3.4 64 km SSE of Atka, Alaska. This one was a foreshock.

Map

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The earthquake

Magnitude: 2.7 (ml), micro
Local time: Mon, Sep 20, 2021, 10:12 AM HADT
UTC: 2021-09-20 19:12:11 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 51.778° N, 173.289° 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 4.9 km horizontally, 2.0 km in depth
Magnitude uncertainty: ±0.15
Depth from: Operator assigned
Station coverage gap: 313°, poorly surrounded by stations
Stations used: 22

Nearby

Within 100 km, magnitude 1.5 and up: 41 in the 60 days after this one and 43 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 us7000fcz0 (also filed as ak021c39q4vj). Read Thu, Sep 24, 2026, 3:07 AM UTC.