Alaska earthquakes

M4.2 earthquake 116 km SSW of Sand Point, Alaska

A magnitude 4.2 earthquake struck 116 km SSW of Sand Point, Alaska on Fri, Jul 31, 2020, 1:19 PM AKDT (21:19 UTC), 25 km (16 mi) below the surface.

A larger quake followed: M5.5 79 km SSW of Sand Point, Alaska. This one was a foreshock.

Sand Point 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: 4.2 (mwr), light
Local time: Fri, Jul 31, 2020, 1:19 PM AKDT
UTC: 2020-07-31 21:19:47 UTC
Depth: 25.0 km (15.6 mi), shallow
Epicenter: 54.332° N, 161.004° W
Region: Alaska
Tsunami flag: No
Status: Reviewed by a seismologist

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: 4.2 Mwr
Nodal plane 1: Strike 67°, dip 73°, rake 78°
Nodal plane 2: Strike 283°, dip 20°, rake 125°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 4.6 km horizontally, 7.5 km in depth
Magnitude uncertainty: ±0.05
Depth from: From location
Station coverage gap: 202°, poorly surrounded by stations
Stations used: 95

Nearest places

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

Sand Point, AlaskaPopulation 1,064. Forecast116 kmSSW

Nearby

Within 100 km, magnitude 1.5 and up: at least 200 in the 60 days after this one and at least 200 in the 30 days before it.

After

The first 60 of at least 200.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us6000b7ny (also filed as ak0209sm371k). Read Sun, Sep 27, 2026, 2:24 PM UTC.