Alaska earthquakes

M4.0 earthquake 54 km ESE of Nikolski, Alaska

A magnitude 4.0 earthquake struck 54 km ESE of Nikolski, Alaska on Mon, Aug 28, 2017, 5:39 PM AKDT (01:39 UTC), 40 km (25 mi) below the surface.

A larger quake followed: M4.7 87 km S of Nikolski, 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: 4.0 (mb, body-wave), light
Magnitude from: USGS National Earthquake Information Center
Local time: Mon, Aug 28, 2017, 5:39 PM AKDT
UTC: 2017-08-29 01:39:48 UTC
Depth: 39.7 km (24.7 mi), shallow
Epicenter: 52.819° N, 168.079° 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
4.0	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.101 · 26 stations
4.0	mb, body-wave	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 6.5 km horizontally, 15.4 km in depth
Magnitude uncertainty: ±0.10
Depth from: From location
Station coverage gap: 178°
Stations used: 112

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast156 kmSW

Nearby

Within 100 km, magnitude 1.5 and up: 66 in the 60 days after this one and 89 in the 30 days before it.

After

The first 60 of 66.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us2000acqh (also filed as ak16736613, ak017b2lcj3g). Read Fri, Oct 2, 2026, 5:45 AM UTC.