M4.2 earthquake 236 km W of Adak, Alaska

A magnitude 4.2 earthquake struck 236 km W of Adak, Alaska on Fri, Feb 9, 2018, 5:09 PM HAST (03:09 UTC), 76 km (47 mi) below the surface.

A larger quake followed: M5.0 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
4.2	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.059 · 81 stations
4.2	mb, body-wave	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: 70 in the 60 days after this one and 38 in the 30 days before it.

The first 60 of 70.

From the USGS Earthquake Hazards Program and its partner networks, event us2000d02u (also filed as ak0181vuviu1). Read Fri, Oct 2, 2026, 2:21 AM UTC.