Alaska earthquakes

M3.7 earthquake 89 km SW of Atka, Alaska

A magnitude 3.7 earthquake struck 89 km SW of Atka, Alaska on Thu, Dec 21, 2017, 5:34 PM HAST (03:34 UTC), 55 km (34 mi) below the surface.

A larger quake followed: M4.9 36 km ESE of Adak, Alaska. This one was a foreshock.

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The earthquake

Magnitude: 3.7 (ML, local (Richter)), minor
Magnitude from: USGS National Earthquake Information Center
Local time: Thu, Dec 21, 2017, 5:34 PM HAST
UTC: 2017-12-22 03:34:30 UTC
Depth: 55.2 km (34.3 mi), shallow
Epicenter: 51.639° N, 175.146° 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
3.7	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed
3.7	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 10.8 km horizontally, 41.8 km in depth
Depth from: From location
Station coverage gap: 199°, poorly surrounded by stations
Stations used: 27

Nearby

Within 100 km, magnitude 1.5 and up: 153 in the 60 days after this one and 53 in the 30 days before it.

After

The first 60 of 153.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us1000bxbg (also filed as ak17637032, ak017gctb7cq). Read Fri, Oct 2, 2026, 4:53 AM UTC.