BUTTE – The ground under the town of Manhattan has been shaking some since the beginning of October, but most people in the area probably haven’t noticed.
“Well, our seismic monitoring network started picking up tiny, little earthquakes near Manhattan on October 3, and since then we’ve recorded and located 25 earthquakes in that area,” said Mike Stickney, the head of the Earthquake Studies Department at Montana Tech in Butte.
This swarm of earthquakes occurring in the area between Three Forks and Belgrade didn’t make itself known until Tuesday when a larger quake was recorded.
“We calculated a magnitude of 3.5 for that earthquake and there were reports from a dozen or so people in the immediate area of the epicenter that reported feeling the earthquake lightly,” Stickney said.
The quake was too small to do any damage.
Stickney says he can’t determine why these swarms occur, and it’s impossible to predict when the next earthquake will happen.
“But certainly once we get a small swarm of events like this there is the possibility of something larger coming along. Most swarms that we have in Western Montana — they are relatively common — don’t amount to anything more than what’s already happened,” he said.
The 3.5 magnitude earthquake that occurred in Manhattan on Tuesday is nothing compared to the 1925 quake in that area which was 1,000 times stronger.
“The estimated magnitude was a 6.6 earthquake that was felt throughout Western Montana and actually caused a fair amount of damage to buildings in Three Forks, Manhattan, as far away as White Sulphur Springs,” Stickney said.
The latest swarm is just a reminder that Montana is earthquake country.
-John Emeigh reporting for MTN News