Alaska earthquakes

M5.5 earthquake 276 km ESE of Chiniak, Alaska

A magnitude 5.5 earthquake struck 276 km ESE of Chiniak, Alaska on Tue, May 8, 2018, 12:14 AM AKDT (08:14 UTC), 6 km (4 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: 5.5 (mww), moderate
Local time: Tue, May 8, 2018, 12:14 AM AKDT
UTC: 2018-05-08 08:14:11 UTC
Depth: 6.0 km (3.7 mi), shallow
Epicenter: 56.296° N, 148.431° W
Region: Alaska
Felt reports: 2
Strongest shaking: II, weak 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: II, weak shaking
Peak ground acceleration: 11.0% of gravity
Peak ground velocity: 0.1 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 II, 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: Strike-slip
Moment magnitude: 5.5 Mww
Nodal plane 1: Strike 160°, dip 58°, rake 160°
Nodal plane 2: Strike 261°, dip 73°, rake 33°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 5.6 km horizontally, 1.8 km in depth
Magnitude uncertainty: ±0.04
Depth from: From modeling of broad-band P waveforms
Station coverage gap: 85°
Stations used: 537

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.

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us1000e0j1 (also filed as ak0185vtmxcv, ak19362293, at00p8ehjn, iscgem611931579). Read Tue, Sep 22, 2026, 3:57 PM UTC.