M3.8 earthquake 16 km N of Susitna, Alaska

A magnitude 3.8 earthquake struck 16 km N of Susitna, Alaska on Sun, Oct 11, 2020, 1:55 PM AKDT (21:55 UTC), 59 km (37 mi) below the surface.

A larger quake followed: M5.1 2 km E of Big Lake, 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
3.8	ML, local (Richter)	Alaska Earthquake Center	Preferred · Preliminary
4.0	Mwr, regional moment	USGS National Earthquake Information Center	Reviewed · ±0.036 · 75 stations

The USGS’s account of the effects of this earthquake.

Also felt at Willow.

From the USGS event page for ak020d3ozvj8. U.S. Geological Survey text and figures are in the public domain.

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

70 people reported to the USGS what they felt; the strongest reported shaking was IV, light shaking.

How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.

Reviewed by a seismologist.

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

Within 100 km, magnitude 1.5 and up: at least 200 in the 60 days after this one and 150 in the 30 days before it.

The first 60 of at least 200.

From the USGS Earthquake Hazards Program and its partner networks, event ak020d3ozvj8 (also filed as us6000c7lp). Read Mon, Oct 5, 2026, 7:52 AM UTC.