M3.0 earthquake 299 km WSW of Adak, Alaska

A magnitude 3.0 earthquake struck 299 km WSW of Adak, Alaska on Sat, Oct 21, 2023, 9:00 PM GMT+12 (09:00 UTC), 26 km (16 mi) below the surface.

A larger quake followed: M5.1 Rat Islands, Aleutian Islands, 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
3.0	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.115 · 10 stations
2.7	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: 99 in the 60 days after this one and 41 in the 30 days before it.

The first 60 of 99.

From the USGS Earthquake Hazards Program and its partner networks, event us7000l993 (also filed as ak023didd0s9). Read Fri, Oct 2, 2026, 6:21 AM UTC.