M3.6 earthquake 15 km NE of Challis, Idaho

A magnitude 3.6 earthquake struck 15 km NE of Challis, Idaho on Sat, Feb 27, 2016, 6:29 PM MST (01:29 UTC), 7 km (5 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
3.6	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.188 · 28 stations
3.6	ML, local (Richter)	Montana Bureau of Mines and Geology	Final · ±0.188 · 28 stations

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

Felt (III) at Challis.

From the USGS event page for us10004t8m. 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.

9 people reported to the USGS what they felt; the strongest reported shaking was III, weak shaking.

Reviewed by a seismologist.

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

Within 100 km, magnitude 1.5 and up: 28 in the 60 days after this one and 31 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event us10004t8m (also filed as mb80127094). Read Thu, Oct 1, 2026, 12:57 PM UTC.