Oklahoma recorded at least 23 earthquakes in the past two days, the largest of which was a 5.6-magnitude tremor that struck late Saturday night, according to reports.
No serious injuries were reported and only minor structural damage came about, according to state officials.
The tremors were felt throughout the Midwest, including in Kansas, Missouri, Arkansas, Texas and Illinois.
Some of the damage reported was to roadways. Officials have said sections of a highway in central-Oklahoma buckled as the ground shook beneath it.
Three separate sections of U.S. Route 62 buckled under the tremors, Aaron Bennett of the Lincoln County 911 and emergency management told CNN.
The region was rattled by a series of smaller tremors surrounding Saturday’s major earthquake, including a 4.0-magnitude earthquake that struck early Sunday morning just 36 miles east of Oklahoma City, officials said.
The weekend’s quakes are consistent with a severe spike in the number of earthquakes hitting the region in recent years.
More than 1,000 earthquakes were recorded in 2010 after seismographs were installed in the area, according to officials. Only around 100 of those earthquakes, however, were strong enough to be felt by people in the area.
It is unclear why there is a sudden spike in the number of reported earthquakes in Oklahoma. Prior to 2010, the state typically had around 50 earthquakes a year, officials said.
Oklahoma has had 10 times more earthquakes than normal since mid-2009, Austin Holland, a research seismologist with the Oklahoma Geological Survey, told The New York Times.
“It could be a natural cycle; we just don’t know,” Holland said.
Oklahoma does not sit on top of a major fault line, which makes it unclear why more seismic activity has been recorded recently, sources said.
The last major earthquake to hit the state was a 5.5-magnitude quake that struck in 1952, according to officials.
The stadium at Oklahoma State University in Stillwater was rocked after the school's football game with Kansas State. Not only did players in the locker room feel the quake, but reporters in the press box felt the earth rocking as well.
ESPN reporter Kirk Herbstreit was one reporter in the press box who as actually live on camera when the quake occurred. His expression conveyed a brief moment of panic as he felt the earth sway.
Here is a clip of Saturday night's game between the Cowboys and the Wildcats (Oklahoma beat Kansas 52-45):