M2.6 earthquake 35 km S of Silver Gate, Montana

A magnitude 2.6 earthquake struck 35 km S of Silver Gate, Montana on Sat, Dec 18, 2021, 2:12 PM MST (21:12 UTC), 15 km (9 mi) below the surface.

A larger quake followed: M2.8 50 km SSE of Mammoth, Wyoming. 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
2.56	ML, local (Richter)	University of Utah Seismograph Stations	Preferred · Final · ±0.433 · 6 stations
2.5	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed · ±0.051 · 50 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: 18 in the 60 days after this one and 10 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event uu60472537 (also filed as us6000gdhd). Read Sun, Oct 4, 2026, 6:53 PM UTC.