Alaska earthquakes

M7.9 earthquake 261 km SE of Chiniak, Alaska

A magnitude 7.9 earthquake struck 261 km SE of Chiniak, Alaska on Tue, Jan 23, 2018, 12:31 AM AKST (09:31 UTC), 14 km (9 mi) below the surface.

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Map

Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 7.9 (mww), major
Local time: Tue, Jan 23, 2018, 12:31 AM AKST
UTC: 2018-01-23 09:31:40 UTC
Depth: 14.1 km (8.7 mi), shallow
Epicenter: 56.004° N, 149.166° W
Region: Alaska
Felt reports: 2,383
Strongest shaking: IV, light shaking
PAGER alert: Green
Tsunami flag: Yes: a large quake in an oceanic region
Status: Reviewed by a seismologist

Tsunami

The USGS flags a quake this large in an oceanic region. The flag does not mean a tsunami happened; the tsunami warning centers decide that, and their messages are below when they issued any.

Current tsunami warnings: tsunami.gov. Warnings in force in the US also appear on our alerts pages.

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: 3.2% of gravity
Peak ground velocity: 2.1 cm/s
Map: Automatic

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

Did you feel it?

2,383 people reported to the USGS what they felt; the strongest reported shaking was VIII, severe 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	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%

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: Strike-slip
Moment magnitude: 7.9 Mww
Nodal plane 1: Strike 259°, dip 74°, rake 10°
Nodal plane 2: Strike 166°, dip 80°, rake 164°
Landslide alert: Green
Liquefaction alert: Green

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 6.0 km horizontally, 2.8 km in depth
Magnitude uncertainty: ±0.03
Depth from: From location
Station coverage gap: 30°
Stations used: 636

Nearest places

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

Nearby

Within 100 km, magnitude 2.5 and up: 200 in the 60 days after this one and 0 in the 30 days before it.

After

The first 60 of 200.

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event us2000cmy3 (also filed as ak18173527, at00p3054t, pt18023001, ak018126wm5v, iscgem611653794, ak18173519). Read Sun, Sep 20, 2026, 9:40 PM UTC.