Alaska earthquakes

M3.7 earthquake 131 km WSW of Adak, Alaska

A magnitude 3.7 earthquake struck 131 km WSW of Adak, Alaska on Tue, Feb 27, 2018, 8:43 PM HAST (06:43 UTC), 16 km (10 mi) below the surface.

A larger quake followed: M4.6 111 km SW of Adak, Alaska. This one was a foreshock.

Map

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

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The earthquake

Magnitude: 3.7 (ML, local (Richter)), minor
Magnitude from: USGS National Earthquake Information Center
Local time: Tue, Feb 27, 2018, 8:43 PM HAST
UTC: 2018-02-28 06:43:01 UTC
Depth: 16.4 km (10.2 mi), shallow
Epicenter: 51.452° N, 178.404° 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 3.3 km horizontally, 6.0 km in depth
Depth from: From location
Station coverage gap: 247°, poorly surrounded by stations
Stations used: 18

Nearby

Within 100 km, magnitude 1.5 and up: 124 in the 60 days after this one and 87 in the 30 days before it.

After

The first 60 of 124.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us1000d14g (also filed as ak18571437, ak0182pojaqa). Read Fri, Oct 2, 2026, 5:45 AM UTC.