Alaska earthquakes

M4.5 earthquake 79 km SSW of Sand Point, Alaska

A magnitude 4.5 earthquake struck 79 km SSW of Sand Point, Alaska on Sun, Aug 20, 2023, 12:56 PM AKDT (20:56 UTC), 46 km (28 mi) below the surface.

A larger quake followed: M5.4 47 km S 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: 4.5 (mwr), light
Local time: Sun, Aug 20, 2023, 12:56 PM AKDT
UTC: 2023-08-20 20:56:40 UTC
Depth: 45.6 km (28.3 mi), shallow
Epicenter: 54.723° N, 161.124° W
Region: Alaska
Felt reports: 2
Strongest shaking: II, 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: II, weak shaking
Peak ground acceleration: 0.2% of gravity
Peak ground velocity: -2.4 cm/s
Map: Automatic

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

Did you feel it?

2 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: Reverse (thrust)
Moment magnitude: 4.5 Mwr
Nodal plane 1: Strike 56°, dip 80°, rake 88°
Nodal plane 2: Strike 245°, dip 10°, rake 100°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 4.3 km horizontally, 3.9 km in depth
Magnitude uncertainty: ±0.07
Depth from: From location
Station coverage gap: 134°
Stations used: 88

Nearest places

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

Sand Point, AlaskaPopulation 1,064. Forecast79 kmSSW

Nearby

Within 100 km, magnitude 1.5 and up: at least 199 in the 60 days after this one and at least 200 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 us7000kppt (also filed as ak023ao0x9zm). Read Wed, Sep 30, 2026, 8:09 PM UTC.