Small earthquake hits 3 miles west of PierrePIERRE — The South Dakota Capitol and other buildings shook briefly Tuesday as a rare earthquake hit the state’s capital city.
By: CHET BROKAW, Associated Press
PIERRE — The South Dakota Capitol and other buildings shook briefly Tuesday as a rare earthquake hit the state’s capital city.
The U.S. Geological Survey’s Earthquake Center confirmed an earthquake with a preliminary magnitude of 3.4 struck about one mile west of Pierre at 2:45 p.m. There were no immediate reports of damage, but people in the city reported hearing multiple booms and feeling buildings shake.
Eric Stasch, operations manager at U.S. Army Corps of Engineering’s Oahe Dam, said an initial check indicated the quake had caused no damage to the massive earthen structure. Officials planned to conduct a more thorough check of the Missouri River dam, located about five miles upstream from Pierre, later Tuesday.
The three motion detectors at the dam were not tripped by the earthquake, Stasch said.
“It wasn’t much here. You could feel it and you heard it, but that’s about it. It was real brief, too. It was just like someone bumped your chair,” Stasch said.
The Geological Survey said the last earthquake recorded in South Dakota was on Feb. 7, 2007, when a 3.1-magnitude quake hit 15 miles west-northwest of Wall in the western part of the state.
Paul Earle, a Geological Survey seismologist, said earthquakes are unusual in South Dakota because there is little seismic activity in the state. But he added that “earthquakes can happen everywhere.”
“There are stresses in the Earth’s crust any place on the planet,” Earle said.
Joe Kafka, a spokesman for Gov. Dennis Daugaard, said there were no early reports of any damage to the Capitol or other state office buildings in Pierre.
People who work in the Capitol building felt the structure shake briefly, he said.
“When a building this size shakes, you know something happened,” Kafka said.
Pierre businessman Bruce Johnson joined other people in the city who hurried outside after the quake to try to determine what had happened.
“It felt like somebody jumped on the roof,” Johnson said. “One big thump and then another thump.”
Some people initially thought the noise and shaking were caused by a sonic boom.
Earle said low-magnitude earthquakes can easily be mistaken for sonic booms because they do not involve prolonged shaking.