Alaska earthquakes

M3.4 earthquake 86 km E of McCarthy, Alaska

A magnitude 3.4 earthquake struck 86 km E of McCarthy, Alaska on Thu, Aug 19, 2021, 9:39 PM AKDT (05:39 UTC), 11 km (7 mi) below the surface.

A larger quake followed: M3.6 52 km SSW of Alcan Border, Alaska. This one was a foreshock.

Tok forecast More in Alaska

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, 9:39 PM AKDT
UTC: 2021-08-20 05:39:29 UTC
Depth: 11.3 km (7.0 mi), shallow
Epicenter: 61.538° N, 141.320° W
Region: Alaska
Strongest shaking: V, moderate 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: V, moderate shaking
Peak ground acceleration: 13.4% of gravity
Peak ground velocity: 0.9 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: Oblique reverse
Moment magnitude: 3.6 Mwr
Nodal plane 1: Strike 135°, dip 22°, rake 127°
Nodal plane 2: Strike 277°, dip 72°, rake 76°

How well it is located

Reviewed by a seismologist.

Stations used: 125

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 27 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 ak021anrw3oz (also filed as us6000f8pk). Read Mon, Sep 28, 2026, 5:54 PM UTC.