M2.5 earthquake 133 km W of Adak, Alaska

A magnitude 2.5 earthquake struck 133 km W of Adak, Alaska on Sat, Nov 21, 2020, 5:03 PM HAST (03:03 UTC), 173 km (108 mi) below the surface.

A larger quake followed: M5.0 124 km SW 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
2.5	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.115 · 10 stations
2.1	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: 77 in the 60 days after this one and 40 in the 30 days before it.

The first 60 of 77.

From the USGS Earthquake Hazards Program and its partner networks, event us7000clzw (also filed as ak020f0ujn6a). Read Fri, Oct 2, 2026, 2:17 AM UTC.