5.8 earthquake shakes Montana
Montana has thousands of earthquakes each year, and people never feel most of them.
That wasn’t the case with the July 6 quake, which measured 5.8 on the Richter Scale. It was the state’s largest since 1964, which was another 5.8 quake whose epicenter was located south of Ennis in the Madison Valley, according to Mike Stickney, who has been a seismologist at the Montana Bureau of Mines and Geology’s Earthquake Studies Office in Butte for 37 years.
He said that Thursday’s temblor lasted 5 to 15 seconds, depending on where a person was located, adding that the time period one felt was longer the farther away one was from the epicenter. Being closer to it would result in a more intense feeling, however.
Earthquakes are caused by shifting or slipping of faults, which are fractures in the earth’s crust.
One can prepare for an earthquake by making sure nothing large or pointed is located above a bed, couch or table where one can be struck if such an object falls.
Although there is precious little time to do anything once a quake hits, Stickney recommends ducking under a table if possible and holding onto one of its legs, for example. If outside, he suggests looking up and being aware of one’s surroundings in order to get away from any buildings or power lines that could fall.
The Mission Valley has a fault that stretches from Bigfork down the east side of Flathead Lake to east of St. Ignatius. The active portion of the fault lies between Pablo and St. Ignatius, he said. There have been no significant quakes measured on that fault over the past 50-100 years, he said, although there was a 7.5 quake some 7,600 years ago.