Alaska earthquakes

M4.1 earthquake 86 km E of McCarthy, Alaska

A magnitude 4.1 earthquake struck 86 km E of McCarthy, Alaska on Thu, Aug 19, 2021, 5:48 PM AKDT (01:48 UTC), 6 km (4 mi) below the surface.

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: 4.1 (ml), light
Local time: Thu, Aug 19, 2021, 5:48 PM AKDT
UTC: 2021-08-20 01:48:15 UTC
Depth: 6.4 km (4.0 mi), shallow
Epicenter: 61.549° N, 141.308° W
Region: Alaska
Felt reports: 1
Strongest shaking: IV, light shaking
PAGER alert: Green
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: IV, light shaking
Peak ground acceleration: 5.5% of gravity
Peak ground velocity: 0.5 cm/s
Map: Automatic

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

Did you feel it?

1 person reported to the USGS what they felt; the strongest reported shaking was II, weak shaking.

Estimated impact

The USGS PAGER system estimates deaths and economic losses from the shaking and the population and buildings exposed to it.

Alert level: Green: little or no damage or loss of life expected

Deaths: estimated chance of each range
Range	Chance
Under 1	65%
1 to 10	30%
10 to 100	4%
100 to 1,000	Under 1%
1,000 to 10,000	Under 1%
10,000 to 100,000	Under 1%
100,000 to 10,000,000	Under 1%

Economic losses: estimated chance of each range
Range, million USD	Chance
Under 1	65%
1 to 10	30%
10 to 100	4%
100 to 1,000	Under 1%
1,000 to 10,000	Under 1%
10,000 to 100,000	Under 1%
100,000 to 10,000,000	Under 1%

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: 4.1 Mwr
Nodal plane 1: Strike 270°, dip 73°, rake 69°
Nodal plane 2: Strike 142°, dip 27°, rake 139°

How well it is located

Reviewed by a seismologist.

Stations used: 151

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 33 in the 60 days after this one and 7 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 ak021anpk9oi (also filed as us6000f8kk). Read Mon, Sep 28, 2026, 4:00 AM UTC.