Carla Knecht felt it just before midnight.
“My husband said my name a couple times and then he said, ‘Are you OK?’ And I said, ‘yeah,’ and we both said, ‘What was that?’”
What they felt was a vibrating jolt. It lasted about 5 seconds. They felt their bed and the house shake. They heard a low rumble.
“I’ve never felt that before, thank God,” Knecht said, “and I hope I never do again.”
But they’re OK, and so is their house. It’s about 7 miles west of the small town of Bowdle in north-central South Dakota.
Geophysicist Don Blakeman said the Tuesday night earthquake’s magnitude was 3.2, well below moderate severity.
“The only thing it could ever possibly do is if you had something sitting precariously on a shelf, it might be just enough to tip it off,” Blakeman said.
He works in Golden, Colorado, at the National Earthquake Information Center. That’s part of the U.S. Geological Survey.
The USGS has seismometers all over the country. About 40 of those stations detected the Bowdle quake, including the closest station near Bismarck, North Dakota.
The quake originated about 3 miles underground. Blakeman said people in the Bowdle area felt the resulting wave of energy rushing through the earth.
“It’s kind of like sound energy, only it’s traveling through the rocks,” Blakeman said. “You could kind of think of the molecules in the crust of the Earth as being dominoes – you push one molecule, it pushes the next one, and that energy keeps pushing along.”
Earthquakes are rare in South Dakota, but there have been two this year. The other one was a 2.5-magnitude quake in August near Platte.
The USGS encourages anyone who felt the Bowdle quake to report it on the agency’s website.
-Contact reporter Seth Tupper by email.