Alaska earthquakes

M4.0 earthquake 77 km SSW of Sand Point, Alaska

A magnitude 4.0 earthquake struck 77 km SSW of Sand Point, Alaska on Tue, Jul 28, 2020, 5:03 PM AKDT (01:03 UTC), 45 km (28 mi) below the surface.

A larger quake followed: M5.6 44 km SSE 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: 4.0 (mwr), light
Local time: Tue, Jul 28, 2020, 5:03 PM AKDT
UTC: 2020-07-29 01:03:23 UTC
Depth: 45.3 km (28.2 mi), shallow
Epicenter: 54.733° N, 161.095° 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: 4.0 Mwr
Nodal plane 1: Strike 68°, dip 82°, rake 63°
Nodal plane 2: Strike 323°, dip 28°, rake 163°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 4.1 km horizontally, 5.1 km in depth
Magnitude uncertainty: ±0.05
Depth from: From location
Station coverage gap: 174°
Stations used: 179

Nearest places

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

Sand Point, AlaskaPopulation 1,064. Forecast77 kmSSW

Nearby

Within 100 km, magnitude 1.5 and up: at least 201 in the 60 days after this one and at least 200 in the 30 days before it.

After

The first 60 of at least 201.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us6000b5s3 (also filed as ak0209oz0cpc). Read Mon, Sep 28, 2026, 6:40 AM UTC.