Alaska earthquakes

M5.1 earthquake Alaska Peninsula

A magnitude 5.1 earthquake struck in the Alaska Peninsula on Wed, Aug 30, 2023, 10:59 AM AKDT (18:59 UTC), 47 km (29 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: 5.1 (Mww, W-phase moment), moderate
Magnitude from: USGS National Earthquake Information Center
Local time: Wed, Aug 30, 2023, 10:59 AM AKDT
UTC: 2023-08-30 18:59:24 UTC
Depth: 46.6 km (28.9 mi), shallow
Epicenter: 54.817° N, 161.212° W
Region: Alaska
Felt reports: 5
Strongest shaking: III, weak shaking
Tsunami flag: No
Status: Reviewed by a seismologist

Magnitude estimates

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
5.1	Mww, W-phase moment	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.047 · 44 stations
5.1	Mww, W-phase moment	Alaska Earthquake Center	Preliminary
5.0	Mwr, regional moment	USGS National Earthquake Information Center	Moment tensor · Reviewed

Shaking

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

Strongest estimated: III, weak shaking
Peak ground acceleration: 1.0% of gravity
Peak ground velocity: -0.6 cm/s
Map: Automatic

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

Did you feel it?

5 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: 5.1 Mww
Nodal plane 1: Strike 247°, dip 35°, rake 100°
Nodal plane 2: Strike 55°, dip 55°, rake 83°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 4.5 km horizontally, 4.5 km in depth
Magnitude uncertainty: ±0.05
Depth from: From location
Station coverage gap: 131°
Stations used: 166

Nearest places

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

Sand Point, AlaskaPopulation 1,064. Forecast73 kmSW

Nearby

Within 100 km, magnitude 2.1 and up: 116 in the 60 days after this one and 63 in the 30 days before it.

After

The first 60 of 116.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000ks64 (also filed as ak023b4j4hh1). Read Thu, Oct 1, 2026, 11:48 PM UTC.