Alaska earthquakes

M2.5 earthquake 56 km SW of Unalaska, Alaska

A magnitude 2.5 earthquake struck 56 km SW of Unalaska, Alaska on Fri, Jul 21, 2017, 1:07 AM AKDT (09:07 UTC), 83 km (51 mi) below the surface.

A larger quake followed: M4.0 54 km ESE 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: 2.5 (ML, local (Richter)), micro
Magnitude from: USGS National Earthquake Information Center
Local time: Fri, Jul 21, 2017, 1:07 AM AKDT
UTC: 2017-07-21 09:07:05 UTC
Depth: 82.7 km (51.4 mi), intermediate-depth
Epicenter: 53.491° N, 167.094° 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
2.5	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed
2.5	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 12.0 km horizontally, 10.8 km in depth
Depth from: From location
Station coverage gap: 192°, poorly surrounded by stations
Stations used: 31

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast56 kmSW

Nearby

Within 100 km, magnitude 1.5 and up: 110 in the 60 days after this one and 59 in the 30 days before it.

After

The first 60 of 110.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us2000a6n2 (also filed as ak16357631, ak0179a7yip2). Read Sun, Oct 4, 2026, 4:26 PM UTC.