Alaska earthquakes

M4.0 earthquake 236 km W of Adak, Alaska

A magnitude 4.0 earthquake struck 236 km W of Adak, Alaska on Sun, Apr 17, 2016, 5:02 AM HADT (14:02 UTC), 175 km (109 mi) below the surface.

A larger quake followed: M4.5 216 km W of Adak, Alaska. This one was a foreshock.

Map

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The earthquake

Magnitude: 4.0 (mb, body-wave), light
Magnitude from: USGS National Earthquake Information Center
Local time: Sun, Apr 17, 2016, 5:02 AM HADT
UTC: 2016-04-17 14:02:50 UTC
Depth: 174.8 km (108.6 mi), intermediate-depth
Epicenter: 52.303° N, 179.980° E
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 · ±0.09 · 33 stations
2.9	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 24.3 km horizontally, 21.2 km in depth
Magnitude uncertainty: ±0.09
Depth from: From location
Station coverage gap: 265°, poorly surrounded by stations
Stations used: 49

Nearby

Within 100 km, magnitude 1.5 and up: 25 in the 60 days after this one and 5 in the 30 days before it.

After

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us10005bvd (also filed as ak13472227, ak0164yue2zo). Read Sun, Oct 4, 2026, 11:04 PM UTC.