Alaska earthquakes

M2.5 earthquake 27 km NW of Adak, Alaska

A magnitude 2.5 earthquake struck 27 km NW of Adak, Alaska on Sun, Aug 12, 2018, 6:23 PM HADT (03:23 UTC), 139 km (87 mi) below the surface.

A larger quake followed: M6.5 108 km WSW of Adak, 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: Sun, Aug 12, 2018, 6:23 PM HADT
UTC: 2018-08-13 03:23:04 UTC
Depth: 139.3 km (86.6 mi), intermediate-depth
Epicenter: 52.022° N, 176.961° 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
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 14.8 km horizontally, 8.3 km in depth
Depth from: From location
Station coverage gap: 183°, poorly surrounded by stations
Stations used: 12

Nearby

Within 100 km, magnitude 1.5 and up: at least 199 in the 60 days after this one and 78 in the 30 days before it.

After

The first 60 of at least 199.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us2000he7c (also filed as ak20253002, ak018ac5ubq0). Read Thu, Oct 1, 2026, 8:08 PM UTC.