A 4.2 magnitude earthquake struck near Great Falls on Thursday, briefly rattling residents and raising questions about why earthquakes occur in the region.

The U.S. Geological Survey confirmed that it registered as a 4.2 quake. The quake happened at 12:41 p.m., and was centered about 4.9 miles northeast of Great Falls at a depth of about 13.6 miles.

Brianna Juneau reports – watch the video here:

Geology professor talks about Montana earthquakes

According to geologists, while earthquakes of that size are uncommon in north-central Montana, the area is far from inactive.

“Although earthquakes of that magnitude are quite rare in the Great Falls area, it’s actually a pretty seismically active region in western Montana,” said Andrew Laskowski, an associate professor of structural geology at Montana State University.

Great Falls lies near the Intermountain Seismic Belt, a geologically active zone that stretches through the western United States. Laskowski said that within this belt, scientists record an average of eight to ten earthquakes every day, though most are too small to be felt.

What exactly causes earthquakes in Montana remains a topic of debate among geologists.

Some researchers believe seismic activity here may be influenced by tectonic plate interactions far to the west, near the Pacific Ocean and the Cascade Mountain Range.

Others point to the distant effects of California’s San Andreas Fault, while another theory focuses on differences in the structure of the Earth’s continental crust.

“In the western U.S., and in particular, we see the seismicity really focused on the mountain fronts,” Laskowski said. “Basically, the east side of the Rocky Mountains. That’s where we see changes in things like how thick the continental crust is.”

Laskowski added that resistance deep below the Earth’s surface, possibly involving the mantle beneath the crust, could also contribute to earthquake activity along those mountain fronts.

Most earthquakes in Montana measure below a magnitude of 2.5 to 3, making them nearly imperceptible to people on the surface.

“We live in a very seismically active state, particularly in the west half of the state,” Laskowski said. “We have to be aware that there is always a risk of major earthquakes.”

Experts say earthquake risk generally increases farther west in Montana, especially near Yellowstone, one of the most seismically active regions in the country. While Thursday’s earthquake was noticeable, geologists emphasize that events of that magnitude are rare in the Great Falls area and may not occur again for several years.

EARTHQUAKES IN MONTANA

The Treasure State is in one of the most seismically active regions in the United States. The intermountain seismic belt, which runs through the western third of the state, is where most of the earthquake activity occurs in Montana. The vast majority of the many quakes across the region are very small, rarely felt by people, and cause no damage. There is a team of experts at the Yellowstone Volcano Observatory who keep track of them all; click here to visit the website.

There is also an Earthquake Studies Office on the campus of Montana Tech in Butte. It operates the Montana Regional Seismic Network, a network of 42 permanent seismic stations located throughout western Montana. The website notes: “Although it has been over four decades since the last destructive earthquake in Montana, small earthquakes are common in the region, occurring at an average rate of 7-10 earthquakes per day.”

The website features several interactive maps, including one that shows the 2,395 earthquakes recorded in Montana during 2018 and additional earthquakes in the surrounding region. All but 23 of those quakes registered as less than 3.0, which demonstrates how small and imperceptible the vast majority are.

There have been some notable earthquakes in Montana’s history, including the 7.3 magnitude Hebgen Lake earthquake on August 17, 1959. The earthquake triggered more than 160 new geysers throughout Yellowstone National Park. There were also around 28 fatalities from a rockslide in Madison Canyon.

And on July 6, 2017, one of the strongest earthquakes to hit Montana in decades shook the community of Lincoln northwest of Helena. It was centered 5.5 miles southeast of Lincoln at a depth of about 2.6 miles. People reported feeling the 5.8 magnitude quake across Montana and the northwest, with some reports coming from as far away as Vancouver and Lethbridge, Canada. It caused some minor damage, but no serious injuries.

In January 2026, a 4.2 quake shook several miles northeast of Great Falls; no injuries and no serious damage were reported – click here for details.

The quake happened at 12:41 p.m., and was centered about 4.9 miles northeast of Great Falls at a depth of about 13.6 miles.

MTN News was interviewing Cascade County Sheriff Jesse Slaughter (for an unrelated story) when the earthquake hit – watch the video:

Residents react as earthquake shakes Great Falls

The plains of central and eastern Montana are much less prone to quakes, but there have been a handful of significant ones reported.

According to the USGS, a 5.3 magnitude earthquake struck northeastern Montana on May 15th, 1909.

Several smaller quakes have been recorded in Roosevelt County, including an estimated 4.5 magnitude quake in the town of Froid that resulted in some damage to a grain bin back in 1943.

Although it has been some time since the state has seen a destructive earthquake, small quakes occur several times every day. Click here to learn more about earthquake preparedness.