Alaska earthquakes

M2.5 earthquake 36 km NE of Adak, Alaska

A magnitude 2.5 earthquake struck 36 km NE of Adak, Alaska on Sat, Aug 20, 2016, 6:17 PM HADT (03:17 UTC), 144 km (89 mi) below the surface.

A larger quake followed: M3.9 73 km NNE 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: Sat, Aug 20, 2016, 6:17 PM HADT
UTC: 2016-08-21 03:17:55 UTC
Depth: 143.7 km (89.3 mi), intermediate-depth
Epicenter: 52.068° N, 176.199° 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 · 19 stations
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 9.6 km horizontally, 4.9 km in depth
Station coverage gap: 118°
Stations used: 19

Nearby

Within 100 km, magnitude 1.5 and up: 71 in the 60 days after this one and 66 in the 30 days before it.

After

The first 60 of 71.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us10006ju2 (also filed as ak13894343, ak016ar1n9u6). Read Sun, Oct 4, 2026, 6:01 AM UTC.