Alaska earthquakes

M5.5 earthquake 45 km ESE of Nikolski, Alaska

A magnitude 5.5 earthquake struck 45 km ESE of Nikolski, Alaska on Sun, Nov 29, 2020, 7:59 PM AKST (04:59 UTC), 34 km (21 mi) below the surface.

A larger quake followed: M6.4 46 km ESE of Nikolski, Alaska. This one was a foreshock.

Unalaska 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: 5.5 (mww), moderate
Local time: Sun, Nov 29, 2020, 7:59 PM AKST
UTC: 2020-11-30 04:59:09 UTC
Depth: 34.0 km (21.1 mi), shallow
Epicenter: 52.745° N, 168.260° W
Region: Alaska
Felt reports: 5
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: 1.7% of gravity
Peak ground velocity: 0.4 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.

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	69%
1 to 10	29%
10 to 100	2%
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: Oblique reverse
Moment magnitude: 5.5 Mww
Nodal plane 1: Strike 250°, dip 34°, rake 126°
Nodal plane 2: Strike 28°, dip 63°, rake 68°
Landslide alert: Green
Liquefaction alert: Green

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 6.3 km horizontally, 1.8 km in depth
Magnitude uncertainty: ±0.04
Depth from: Operator assigned
Station coverage gap: 106°
Stations used: 155

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast170 kmSW

Nearby

Within 100 km, magnitude 2.5 and up: 99 in the 60 days after this one and 21 in the 30 days before it.

After

The first 60 of 99.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000cl2f (also filed as usauto7000cl2f, ak020fe3rnz3, iscgem619561745). Read Wed, Sep 30, 2026, 9:18 PM UTC.