M5.1 earthquake 93 km SSE of Old Harbor, Alaska

A magnitude 5.1 earthquake struck 93 km SSE of Old Harbor, Alaska on Tue, Apr 11, 1978, 7:22 PM GMT-10 (05:22 UTC), 24 km (15 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
5.1	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed
5.91	Mw, moment	ISC-GEM global catalog	Final · ±0.2

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Distance and direction from each place to the epicenter, with its forecast.

Within 100 km, magnitude 2.1 and up: 11 in the 60 days after this one and 5 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event usp0000u23 (also filed as iscgem683651). Read Thu, Oct 1, 2026, 6:06 PM UTC.