Alaska earthquakes

M3.9 earthquake 105 km NNE of Adak, Alaska

A magnitude 3.9 earthquake struck 105 km NNE of Adak, Alaska on Thu, Sep 13, 2018, 5:14 PM HADT (02:14 UTC), 204 km (127 mi) below the surface.

A larger quake followed: M4.0 102 km NNE of Adak, Alaska. This one was a foreshock.

Map

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The earthquake

Magnitude: 3.9 (mb, body-wave), minor
Magnitude from: USGS National Earthquake Information Center
Local time: Thu, Sep 13, 2018, 5:14 PM HADT
UTC: 2018-09-14 02:14:17 UTC
Depth: 203.7 km (126.6 mi), intermediate-depth
Epicenter: 52.755° N, 176.075° 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
3.9	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.133 · 15 stations
3.4	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 14.0 km horizontally, 12.4 km in depth
Magnitude uncertainty: ±0.13
Depth from: From location
Station coverage gap: 132°
Stations used: 26

Nearby

Within 100 km, magnitude 1.5 and up: 25 in the 60 days after this one and 16 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 us2000hi7h (also filed as ak018bt2e3j4). Read Thu, Oct 1, 2026, 11:02 PM UTC.