M4.5 earthquake 135 km SE of Atka, Alaska

A magnitude 4.5 earthquake struck 135 km SE of Atka, Alaska on Sun, Aug 6, 2023, 1:04 PM HADT (22:04 UTC), 18 km (11 mi) below the surface.

Map

Where this earthquake was located, with the others nearby. Select one for its page.

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
4.5	Mwr, regional moment	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.061 · 26 stations
4.5	Mwr, regional moment	Alaska Earthquake Center	Preliminary

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

No one has reported feeling this quake to the USGS.

How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.

Reviewed by a seismologist.

Within 100 km, magnitude 1.5 and up: 95 in the 60 days after this one and 23 in the 30 days before it.

The first 60 of 95.

From the USGS Earthquake Hazards Program and its partner networks, event us6000kyc9 (also filed as ak023a0waa6n). Read Fri, Oct 2, 2026, 8:12 AM UTC.