M4.0 earthquake 96 km ESE of Adak, Alaska

A magnitude 4.0 earthquake struck 96 km ESE of Adak, Alaska on Sat, Nov 23, 2019, 11:53 PM HAST (09:53 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M4.7 87 km SW of Atka, 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
4.0	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.106 · 24 stations
3.5	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: 180 in the 60 days after this one and 137 in the 30 days before it.

The first 60 of 180.

From the USGS Earthquake Hazards Program and its partner networks, event us70006eit (also filed as ak019f2ly46u). Read Thu, Oct 1, 2026, 9:34 AM UTC.