M4.7 earthquake 81 km NE of Adak, Alaska

A magnitude 4.7 earthquake struck 81 km NE of Adak, Alaska on Fri, Apr 21, 2023, 9:17 AM HADT (18:17 UTC), 171 km (106 mi) below the surface.

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
4.7	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.029 · 366 stations
4.7	mb, body-wave	Alaska Earthquake Center	Preliminary

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

2 people reported to the USGS what they felt; the strongest reported shaking was II, weak shaking.

Reviewed by a seismologist.

Within 100 km, magnitude 1.7 and up: 59 in the 60 days after this one and 27 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event us6000k662 (also filed as ak02353vgzrv). Read Thu, Oct 1, 2026, 3:39 AM UTC.