M2.4 earthquake 34 km NE of Challis, Idaho

A magnitude 2.4 earthquake struck 34 km NE of Challis, Idaho on Tue, Sep 18, 2018, 1:00 AM MDT (07:00 UTC), 11 km (7 mi) below the surface.

A larger quake followed: M2.5 12 km NNE of Stanley, Idaho. 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
2.4	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.057 · 40 stations
2.5	ML, local (Richter)	Montana Bureau of Mines and Geology	Final · ±0.14 · 16 stations

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 1.5 and up: 24 in the 60 days after this one and 12 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event us2000hg8v (also filed as mb80310369). Read Sat, Oct 3, 2026, 9:44 AM UTC.