Alaska earthquakes

M2.5 earthquake 77 km WNW of Atka, Alaska

A magnitude 2.5 earthquake struck 77 km WNW of Atka, Alaska on Mon, Apr 18, 2016, 6:04 AM HADT (15:04 UTC), 243 km (151 mi) below the surface.

A larger quake followed: M4.1 101 km ESE 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: 2.5 (ML, local (Richter)), micro
Magnitude from: USGS National Earthquake Information Center
Local time: Mon, Apr 18, 2016, 6:04 AM HADT
UTC: 2016-04-18 15:04:59 UTC
Depth: 242.5 km (150.7 mi), intermediate-depth
Epicenter: 52.358° N, 175.312° 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 58.5 km horizontally, 9.1 km in depth
Stations used: 18

Nearby

Within 100 km, magnitude 1.5 and up: 74 in the 60 days after this one and 36 in the 30 days before it.

After

The first 60 of 74.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us10005bu0 (also filed as ak13498510, ak01650ijbcm). Read Sun, Oct 4, 2026, 8:53 PM UTC.