Small Montana Earthquake Recorded Along Flathead Lake
It probably wasn't enough to spill your coffee. But residents living around Flathead Lake might have noticed something unusual Monday afternoon. And checking the data, we found the center of a small earthquake in western Lake County.
The U.S. Geological Survey recorded the 2.9 magnitude quake just after noon on Monday, 12:05 pm to be exact, just northwest of Big Arm along the western shore of the lake.
The quake was of a moderate depth, 7.6 miles below the surface and was less than a mile north of Elmo. That's in the same area where the Elmo 2 fire burned earlier this summer.
Generally, a 2.9 magnitude quake is right at the edge of where people will notice something has happened. You might feel a slight rumble or noise. Generally, you won't notice movement, or anything falling off shelves, although that can happen if the quake is shallow.
Just over 10 years ago, a number of small quakes had been reported in the same general area, around Hot Springs and west of the lake. And geologists have long known of several fault lines in that area, including one fault that's located near the base of the Mission Mountains.
But Montana, and especially Western Montana, is well-known earthquake country. Gallatin County Emergency Management outlines the hazards on its Ready Gallatin website, noting that Montana has 7 to 10 earthquakes every day, making it the fourth most seismically active state in the United States. Many of those quakes are related to the seismic activity around Yellowstone.
If you felt the quake Monday, you can file a report with the U.S.G.S. That helps the agency to track and research earthquakes in our region.