M1.9 earthquake 82 km W of Adak, Alaska

A magnitude 1.9 earthquake struck 82 km W of Adak, Alaska on Tue, Feb 18, 2020, 10:23 PM HAST (08:23 UTC), 8 km (5 mi) below the surface.

A larger quake followed: M5.0 71 km WNW 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
1.9	ML, local (Richter)	Alaska Earthquake Center	Preferred · Preliminary
1.81	ML, local (Richter)	AV	Final · ±0.232 · 11 stations

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 at least 200 in the 30 days before it.

The first 60 of at least 199.

From the USGS Earthquake Hazards Program and its partner networks, event ak0202atrubm (also filed as av62137346). Read Fri, Oct 2, 2026, 7:25 PM UTC.