Alaska earthquakes

M3.7 earthquake 30 km WNW of Willow, Alaska

A magnitude 3.7 earthquake struck 30 km WNW of Willow, Alaska on Sun, Aug 8, 2021, 9:32 PM AKDT (05:32 UTC), 60 km (38 mi) below the surface.

A larger quake followed: M4.3 30 km WNW of Willow, Alaska. This one was a foreshock.

Willow forecast More in Alaska

Map

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

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The earthquake

Magnitude: 3.7 (ml), minor
Local time: Sun, Aug 8, 2021, 9:32 PM AKDT
UTC: 2021-08-09 05:32:51 UTC
Depth: 60.4 km (37.5 mi), shallow
Epicenter: 61.860° N, 150.555° W
Region: Alaska
Felt reports: 76
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: 0.5% of gravity
Peak ground velocity: -2.0 cm/s
Map: Automatic

USGS ShakeMap: estimated shaking intensity around the epicenter — Estimated shaking intensity. Map: USGS ShakeMap.

Did you feel it?

76 people reported to the USGS what they felt; the strongest reported shaking was III, weak shaking.

Fault motion and ground failure

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

Faulting: Strike-slip
Moment magnitude: 3.8 Mwr
Nodal plane 1: Strike 33°, dip 49°, rake 6°
Nodal plane 2: Strike 299°, dip 86°, rake 139°

How well it is located

Reviewed by a seismologist.

Stations used: 204

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: at least 199 in the 60 days after this one and 117 in the 30 days before it.

After

The first 60 of at least 199.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event ak021a5kxtzc (also filed as us6000f3is). Read Fri, Sep 25, 2026, 5:18 PM UTC.