M4.2 earthquake 188 km WSW of Adak, Alaska

A magnitude 4.2 earthquake struck 188 km WSW of Adak, Alaska on Tue, May 21, 1996, 12:24 AM HADT (09:24 UTC), 33 km (21 mi) below the surface.

A larger quake followed: M6.5 111 km WSW 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
4.2	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · 22 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 8 in the 30 days before it.

The first 60 of 70.

From the USGS Earthquake Hazards Program and its partner networks, event usp0007hmz (also filed as ak9966iztcnj). Read Sat, Oct 3, 2026, 3:56 AM UTC.