Seismic activity in Montana means potential for large earthquake
KALISPELL, Mont. — Western Montana is a hotbed of seismic activity. There have been 16 earthquakes in the area since Jan. 1, and scientists say a big earthquake is a possibility, but there’s no way to predict when that could happen.
Montana Bureau of Mines and Geology earthquake studies office director Dr. Mike Stickney said there are thousands of small fault lines that run deep beneath the ground in western Montana. The Mission Fault -- a big one -- runs through Flathead Lake and along the Mission Mountain Range.
“There is a possibility that a large earthquake could occur,” Stickney said.
Scientists discovered the last major earthquake at the Mission Fault occurred around 7,000 years ago.
“In a geologic perspective, that was yesterday,” Stickney said.
Stickney said the Mission Fault has the potential to create a 7 to 7.5-magnitude earthquake. In comparison, the 1994 Northridge earthquake in the San Fernando Valley was a magnitude 6.7, the 1989 San Francisco earthquake was a magnitude 6.9, and the 1906 San Francisco earthquake was a magnitude 7.9.
Closer to home, the 2017 earthquake in Lincoln was a magnitude 5.8. Stickney said that quake was felt as far north as Calgary, Canada, and as far west as Seattle.
While there is the potential for a large earthquake, most of the ones recorded in Montana are small.
“In western Montana we average five to 10 tiny earthquakes per day,” Stickney said.
They don’t always occur on fault lines. Western Montana lies in the intermountain seismic belt, which Stickney said extends from Kalispell to Yellowstone. Earthquakes can occur anywhere in this area. This year most of the recorded earthquakes have occurred around Manhattan and Lincoln.
“We still do not understand why, along this intermountain seismic belt, it seems characteristic of this zone of activity, that most of the small earthquakes do not line up along the big faults that we know about,” Stickney said.
Although smaller earthquakes are more common, Stickney said people should still be prepared for a big one.
“This is earthquake country,” Stickney said.
There are some safety precautions you can take now to prepare for an earthquake. The Federal Emergency Management Agency suggests securing things like bookcases, home electronics, appliances and items hanging from walls and ceilings so they don’t fall and cause injury in an earthquake.
During an earthquake FEMA says to drop on your hands and knees, cover your head and neck with your arms and hold on to steady furniture until shaking stops. If in bed, stay there and cover your head and neck with a pillow.
