Alaska earthquakes

M4.2 earthquake 27 km NNW of Atka, Alaska

A magnitude 4.2 earthquake struck 27 km NNW of Atka, Alaska on Sat, Feb 20, 2016, 5:42 AM HAST (15:42 UTC), 192 km (119 mi) below the surface.

A larger quake followed: M6.3 72 km SSE of Atka, Alaska. This one was a foreshock.

Map

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The earthquake

Magnitude: 4.2 (mb, body-wave), light
Magnitude from: USGS National Earthquake Information Center
Local time: Sat, Feb 20, 2016, 5:42 AM HAST
UTC: 2016-02-20 15:42:41 UTC
Depth: 192.1 km (119.4 mi), intermediate-depth
Epicenter: 52.418° N, 174.381° 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
4.2	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.083 · 40 stations
3.5	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 15.4 km horizontally, 6.9 km in depth
Magnitude uncertainty: ±0.08
Stations used: 30

Nearby

Within 100 km, magnitude 1.5 and up: 82 in the 60 days after this one and 38 in the 30 days before it.

After

The first 60 of 82.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us10004s3s (also filed as ak12859221, ak0162cllai3). Read Mon, Oct 5, 2026, 12:08 PM UTC.