M1.5 earthquake 5 km S of Boulder, Montana

A magnitude 1.5 earthquake struck 5 km S of Boulder, Montana on Sun, Feb 1, 2015, 8:39 AM MST (15:39 UTC), 8 km (5 mi) below the surface.

Automatic solution: the magnitude and location may still be revised.

A larger quake followed: M2.7 4 km SSE of Helena Valley Northwest, Montana. This one was a foreshock.

Map

Where this earthquake was located, with the others nearby. Select one for its page.

No one has reported feeling this quake to the USGS.

An automatic solution; a seismologist may revise it.

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

Within 100 km, magnitude 1.5 and up: 8 in the 60 days after this one and 4 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event mb15632582. Read Mon, Oct 5, 2026, 4:05 AM UTC.