Alaska earthquakes

M2.5 earthquake 266 km WSW of Adak, Alaska

A magnitude 2.5 earthquake struck 266 km WSW of Adak, Alaska on Mon, Aug 20, 2018, 11:25 AM GMT+12 (23:25 UTC), 35 km (22 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: 2.5 (ML, local (Richter)), micro
Magnitude from: USGS National Earthquake Information Center
Local time: Mon, Aug 20, 2018, 11:25 AM GMT+12
UTC: 2018-08-19 23:25:28 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 51.097° N, 179.739° 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
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 10.0 km horizontally, 2.0 km in depth
Depth from: Operator assigned
Station coverage gap: 245°, poorly surrounded by stations
Stations used: 7

Nearby

Within 100 km, magnitude 1.5 and up: 70 in the 60 days after this one and 65 in the 30 days before it.

After

The first 60 of 70.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us2000hhrb (also filed as ak20117959, ak018amezk8y). Read Fri, Oct 2, 2026, 10:12 PM UTC.