Alaska earthquakes

M3.7 earthquake 237 km W of Adak, Alaska

A magnitude 3.7 earthquake struck 237 km W of Adak, Alaska on Sat, Aug 11, 2018, 10:39 AM GMT+12 (22:39 UTC), 73 km (45 mi) below the surface.

A larger quake followed: M4.2 Andreanof Islands, Aleutian Islands, 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: Sat, Aug 11, 2018, 10:39 AM GMT+12
UTC: 2018-08-10 22:39:36 UTC
Depth: 72.7 km (45.2 mi), intermediate-depth
Epicenter: 51.527° N, 179.979° E
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 3.7 km horizontally, 7.2 km in depth
Depth from: From location
Station coverage gap: 172°
Stations used: 21

Nearby

Within 100 km, magnitude 1.5 and up: 100 in the 60 days after this one and 64 in the 30 days before it.

After

The first 60 of 100.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us1000gbup (also filed as ak018a7in0md, ak20057624). Read Fri, Oct 2, 2026, 12:19 AM UTC.