Alaska earthquakes

M4.9 earthquake 81 km S of Atka, Alaska

A magnitude 4.9 earthquake struck 81 km S of Atka, Alaska on Mon, Oct 11, 2021, 9:25 AM HADT (18:25 UTC), 35 km (22 mi) below the surface.

Map

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The earthquake

Magnitude: 4.9 (mb), light
Local time: Mon, Oct 11, 2021, 9:25 AM HADT
UTC: 2021-10-11 18:25:48 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 51.479° N, 174.430° 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: 0.2% of gravity
Peak ground velocity: -2.6 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 2.4 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.04
Depth from: Operator assigned
Station coverage gap: 127°
Stations used: 188

Nearby

Within 100 km, magnitude 1.9 and up: 60 in the 60 days after this one and 23 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 us6000ftru (also filed as ak021d1zhtzc, iscgem621145559). Read Thu, Sep 24, 2026, 7:06 AM UTC.