Alaska earthquakes

M5.1 earthquake 75 km SE of Atka, Alaska

A magnitude 5.1 earthquake struck 75 km SE of Atka, Alaska on Sat, May 22, 2021, 12:04 AM HADT (09:04 UTC), 21 km (13 mi) below the surface.

Map

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

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The earthquake

Magnitude: 5.1 (mww), moderate
Local time: Sat, May 22, 2021, 12:04 AM HADT
UTC: 2021-05-22 09:04:40 UTC
Depth: 21.0 km (13.0 mi), shallow
Epicenter: 51.741° N, 173.392° W
Region: Alaska
Strongest shaking: III, 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: III, weak shaking
Peak ground acceleration: 0.6% of gravity
Peak ground velocity: -1.0 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.

Fault motion and ground failure

How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.

Faulting: Reverse (thrust)
Moment magnitude: 5.1 Mww
Nodal plane 1: Strike 242°, dip 20°, rake 78°
Nodal plane 2: Strike 75°, dip 70°, rake 94°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 8.1 km horizontally, 4.7 km in depth
Magnitude uncertainty: ±0.08
Depth from: From location
Station coverage gap: 128°
Stations used: 140

Nearby

Within 100 km, magnitude 2.1 and up: 39 in the 60 days after this one and 16 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 us7000e5a6 (also filed as ak0216izp4g7, iscgem620438017, ak0216izp4q5). Read Thu, Sep 24, 2026, 10:10 AM UTC.