Alaska earthquakes

M4.1 earthquake 108 km SSW of Nikolski, Alaska

A magnitude 4.1 earthquake struck 108 km SSW of Nikolski, Alaska on Thu, Feb 15, 2018, 9:02 PM AKST (06:02 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M4.9 130 km WSW 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: 4.1 (mb, body-wave), light
Magnitude from: USGS National Earthquake Information Center
Local time: Thu, Feb 15, 2018, 9:02 PM AKST
UTC: 2018-02-16 06:02:04 UTC
Depth: 10.0 km (6.2 mi), shallow
Epicenter: 52.005° N, 169.306° W
Region: Alaska
Strongest shaking: I, not felt 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
4.1	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.097 · 29 stations
4.1	mb, body-wave	Alaska Earthquake Center	Preliminary

Shaking

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

Strongest estimated: I, not felt shaking
Map: Automatic

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

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 5.4 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.10
Depth from: Operator assigned
Station coverage gap: 183°, poorly surrounded by stations
Stations used: 98

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast279 kmSW

Nearby

Within 100 km, magnitude 1.5 and up: 54 in the 60 days after this one and 20 in the 30 days before it.

After

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us2000d32d (also filed as ak01825tucry, ak18437706). Read Thu, Oct 1, 2026, 4:51 PM UTC.