An urban search and rescue training course that Kalispell Fire Department captain Rob Cherot took this summer should help firefighters be a little more prepared to respond to a building collapse in the event of a strong earthquake.

An earthquake?

“There’s multiple risks out there when we as a fire department look at the things that can happen. Earthquakes being one of those things,” Kalispell Fire Chief Dave Dedman said.

The training is a low-cost effort to try to be more prepared for one of the natural hazards that could get thrown the small fire department’s way. Cherot attended the weeklong training in June sponsored by the Montana State Fire Services Training School.

“They worked on stabilizing an incident, shoring walls, moving large heavy concrete walls, cutting through concrete walls and just kind of learning more about the tools we already have and how we can use them in that capacity,” Dedman said.

Cherot will share what he learned with the rest of the fire department. The training should help firefighters respond to a building collapse — whether that collapse is because of an earthquake, vehicle crash or heavy snow load.

The Kalispell Fire Department has minimal ability to respond to such an incident and would have to rely on help from public and private sector partners, but every bit of preparation helps, Dedman said.

Dedman’s not too worried about Kalispell getting hit by the “Big One.” But earthquakes are possible. He remembers a moderate earthquake in the mid-1970s when he was a child living in Somers. The magnitude 5 tremor was centered near Creston.

“I remember waking up to it,” Dedman said. “It was not a huge shake, but it was enough to wake you up.”

Kalispell lies within the Intermountain Seismic Belt, a large area that runs from Northwest Montana to Utah and branches into Idaho. A complex network of faults — some believed to be more active than others — make Western Montana one of the most seismically active regions in the United States.

“The potential exists for a significant earthquake. It’s just one of those multiple hazards facing us,” said Mike Stickney, director of the Earthquake Studies Office at the Montana Bureau of Mines and Geology in Butte.

Thirty-five seismic sensors in Western Montana report data to the Earthquake Studies Office. Four or five quakes are registered on an average day, but most are under magnitude 3 and either too small or too remote for anyone to feel.

Larger quakes are possible in Montana. They just haven’t happened in a while.

A magnitude 6.75 earthquake hit Three Forks in June 1925, the first significant quake in Montana in the 20th century. The event caused “violent shaking” in a 1,600-square-kilometer area in Southwest Montana and was felt as far away as Wyoming, Canada, North Dakota and Washington. Unreinforced brick buildings were damaged in Three Forks, Manhattan, Logan and Lombard.

A series of strong magnitude 6 earthquakes and aftershocks hit Helena in October 1935. They caused four deaths, several injuries and structural damage to more than half of the buildings in the city, Stickney said.

Montana’s strongest recorded earthquake was a magnitude 7.5 at Hebgen Lake in August 1959. It’s also one of the strongest quakes ever recorded in the Intermountain Seismic Belt.

Shaking from the earthquake sent water spilling over the dam at Hebgen Lake and cracked the dam. The earthquake damaged numerous summer homes and highways in the area and triggered massive landslides in the Madison River Canyon that buried 26 people at a campground and blocked the flow of the Madison River.

Within a few weeks a new 170-foot-deep lake, Earthquake Lake, formed in the canyon.

A maximum intensity of X was assigned was assigned to the Hebgen Lake quake. That’s the third-strongest measure of shaking intensity and represents a quake capable of damaging or destroying even well-built structures.

“Through 1960 we were seeing a magnitude 6 quake or larger once per decade. We’ve gone over 50 years without one,” Stickney said.

Earthquakes have rattled the Flathead and Swan valleys, but nothing stronger than a magnitude 6 in recorded history. That’s considered to be a serious quake capable of damaging at least some buildings, especially older buildings.

A magnitude 5.5 quake centered near Flathead Lake was recorded in September 1945. “Pronounced tremors” rattled windows and dishes from Helena to Walla Walla, Wash., but did not cause substantial damage.

A magnitude 4.7 quake hit Big Arm, Dayton and Proctor in April 1969. The shock was felt over 26,000 square kilometers and followed by at least 21 aftershocks through the end of the month.

A swarm of small earthquakes hit Kila in 1994. The largest was a magnitude 4.5. “There was no damage, but it was quite alarming to residents who had moved in recently and were unaware there are earthquakes,” Stickney said.

Many people living in Western Montana nowadays don’t know the region is prone to earthquakes, Stickney said. “That’s driven in large part by the fact that we haven’t had any large quakes in living memory of most of our population. Older generation folks certainly remember some of them and the information is available online for people inclined to look it up. But most people aren’t aware this is earthquake country.”

Hoping to boost that public awareness, Montana will participate in the Great Rocky Mountain Shakeout campaign in October.

The multi-state drill encourages people to practice dropping, covering and holding on; to do a “hazard hunt” for items that could fall and injure someone during an earthquake; to create a personal disaster plan; and to identify and correct any structural deficiencies in their homes and businesses.

Reporter Tom Lotshaw may be reached at 758-4483 or by email at tlotshaw@dailyinterlake.com.