U.S. Geological Survey researchers say they're upgrading the strength of an Oklahoma earthquake that struck over the weekend to a 5.8 magnitude, making it the most powerful earthquake ever recorded in the state.
USGS research geophysicist Daniel McNamara said Wednesday the previous strongest recorded quake in Oklahoma -- a 5.6-magnitude temblor in 2011 -- also is being upgraded to a 5.7-magnitude quake.
Saturday's earthquake centered near the north-central town of Pawnee, Oklahoma, at about 7:02 a.m., damaged more than a dozen buildings and left one man with a minor head injury after a fireplace collapsed.
McNamara says the volume of injected wastewater from oil and gas activity likely played a role.
He says Oklahoma's two earthquakes this year greater than magnitude 5.0 will increase the likelihood of larger quakes in the future.
Saturday's earthquake rattled a swath of the Great Plains, from Nebraska to North Texas.
The United States Geological Survey first reported the earthquake's magnitude as a 5.6. Officials also reported a 3.1 earthquake east of Luther and a 3.2 quake east-northeast of Medford in the state.
Pawnee County Sheriff Mike Waters said a barn near the epicenter was fully damaged and the jail sustained some minor damage.
USGS geophysicist Robert Sanders described the quake as "one of the largest events in Oklahoma in the last few years." He said it was shallow, about a couple of miles deep.
People in North Texas, Kansas City and St. Louis, Missouri; Fayetteville, Arkansas; Des Moines, Iowa; and Norman, Oklahoma, all reported feeling the earthquake. No major damage was immediately reported.
An increase in magnitude 3.0 or greater earthquakes in Oklahoma has been linked to underground disposal of wastewater from oil and natural gas production. State regulators have asked producers to reduce wastewater disposal volumes in earthquake-prone regions of the state.
Some parts of Oklahoma now match northern California for the nation's most shake prone, and one Oklahoma region has a 1 in 8 chance of a damaging quake in 2016, with other parts closer to 1 in 20.
Sean Weide in Omaha, Nebraska, told The Associated Press that he'd never been in an earthquake before and thought he was getting dizzy. Weide said he and one of his daughters "heard the building start creaking" and said it "was surreal."