Alaska earthquakes

M4.0 earthquake 96 km SSE of Atka, Alaska

A magnitude 4.0 earthquake struck 96 km SSE of Atka, Alaska on Sat, Mar 12, 2016, 2:40 AM HAST (12:40 UTC), 22 km (14 mi) below the surface.

A larger quake followed: M6.3 72 km SSE of Atka, 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: 4.0 (mb, body-wave), light
Magnitude from: USGS National Earthquake Information Center
Local time: Sat, Mar 12, 2016, 2:40 AM HAST
UTC: 2016-03-12 12:40:07 UTC
Depth: 21.8 km (13.5 mi), shallow
Epicenter: 51.349° N, 173.915° 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
4.0	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.063 · 69 stations
4.0	mb, body-wave	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 2.0 km horizontally, 6.0 km in depth
Magnitude uncertainty: ±0.06
Depth from: From location
Station coverage gap: 196°, poorly surrounded by stations
Stations used: 105

Nearby

Within 100 km, magnitude 1.5 and up: at least 199 in the 60 days after this one and 50 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 us20005a7u (also filed as ak12969012, ak0163ba2s0w). Read Sun, Oct 4, 2026, 5:33 PM UTC.