Alaska earthquakes

M3.0 earthquake 175 km W of Adak, Alaska

A magnitude 3.0 earthquake struck 175 km W of Adak, Alaska on Mon, Sep 18, 2017, 7:17 AM HADT (16:17 UTC), 121 km (75 mi) below the surface.

A larger quake followed: M4.8 131 km WSW of Adak, Alaska. This one was a foreshock.

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Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 3.0 (ML, local (Richter)), minor
Magnitude from: USGS National Earthquake Information Center
Local time: Mon, Sep 18, 2017, 7:17 AM HADT
UTC: 2017-09-18 16:17:40 UTC
Depth: 121.4 km (75.5 mi), intermediate-depth
Epicenter: 52.055° N, 179.173° 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
3.0	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed
2.8	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 16.6 km horizontally, 14.3 km in depth
Depth from: From location
Station coverage gap: 210°, poorly surrounded by stations
Stations used: 17

Nearby

Within 100 km, magnitude 1.5 and up: 189 in the 60 days after this one and 120 in the 30 days before it.

After

The first 60 of 189.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us2000aq9y (also filed as ak16849187, ak017bzww8w7). Read Fri, Oct 2, 2026, 8:31 AM UTC.