Alaska earthquakes

M4.0 earthquake 229 km W of Adak, Alaska

A magnitude 4.0 earthquake struck 229 km W of Adak, Alaska on Wed, Aug 16, 2023, 1:19 PM HADT (22:19 UTC), 223 km (138 mi) below the surface.

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The earthquake

Magnitude: 4.0 (mb, body-wave), light
Magnitude from: USGS National Earthquake Information Center
Local time: Wed, Aug 16, 2023, 1:19 PM HADT
UTC: 2023-08-16 22:19:35 UTC
Depth: 222.6 km (138.3 mi), intermediate-depth
Epicenter: 52.107° N, 179.949° 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 · ±0.164 · 10 stations
3.1	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 7.9 km horizontally, 6.2 km in depth
Magnitude uncertainty: ±0.16
Depth from: From location
Station coverage gap: 113°
Stations used: 36

Nearby

Within 100 km, magnitude 1.5 and up: 101 in the 60 days after this one and 56 in the 30 days before it.

After

The first 60 of 101.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000knwc (also filed as ak023ahfqujd). Read Thu, Oct 1, 2026, 10:21 PM UTC.