M3.3 earthquake 75 km SSE of Adak, Alaska

A magnitude 3.3 earthquake struck 75 km SSE of Adak, Alaska on Tue, Aug 1, 2023, 12:02 AM HADT (09:02 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M5.0 44 km SSE of Adak, Alaska. This one was a foreshock.

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
3.3	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.242 · 4 stations
2.9	ML, local (Richter)	Alaska Earthquake Center	Preliminary

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Within 100 km, magnitude 1.5 and up: at least 199 in the 60 days after this one and 127 in the 30 days before it.

The first 60 of at least 199.

From the USGS Earthquake Hazards Program and its partner networks, event us6000kzvg (also filed as ak0239seu9pd). Read Thu, Oct 1, 2026, 2:16 PM UTC.