Alaska earthquakes

M3.3 earthquake 258 km ESE of Chiniak, Alaska

A magnitude 3.3 earthquake struck 258 km ESE of Chiniak, Alaska on Thu, Feb 22, 2018, 4:55 AM AKST (13:55 UTC), 21 km (13 mi) below the surface.

A larger quake followed: M5.4 252 km ESE of Chiniak, Alaska. This one was a foreshock.

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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: 3.3 (ML, local (Richter)), minor
Magnitude from: USGS National Earthquake Information Center
Local time: Thu, Feb 22, 2018, 4:55 AM AKST
UTC: 2018-02-22 13:55:12 UTC
Depth: 20.6 km (12.8 mi), shallow
Epicenter: 56.505° N, 148.536° W
Region: Alaska
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
3.3	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.042 · 76 stations
3.1	ML, local (Richter)	Alaska Earthquake Center	Preliminary

Did you feel it?

No one has reported feeling this quake to the USGS.

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 7.7 km horizontally, 9.9 km in depth
Magnitude uncertainty: ±0.04
Depth from: From location
Station coverage gap: 169°
Stations used: 86

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: at least 202 in the 60 days after this one and at least 200 in the 30 days before it.

After

The first 60 of at least 202.

Before

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event us2000d9xd (also filed as ak18488974, ak0182fvjupy). Read Thu, Oct 1, 2026, 3:04 AM UTC.