Oklahoma was subject to several powerful earthquakes over the weekend, with one on Saturday night breaking the record for the most powerful quake in state history.
The record-breaking quake in question, a magnitude 5.6, started at 10:53 p.m. and lasted for about a minute, causing structural damage to some homes and in one instance, toppling a spire on Benedictine Hall at St. Gregory’s University in Shawnee, Okla.
Facebook and other social media sites experienced an influx in mentions of the Oklahoma earthquake, and “Earthquake in Oklahoma” became a trending topic on Twitter.
“I was watching an HBO series called ‘Oz,’ it’s about the Oswald State Penitentiary, so that was pretty terrifying to be watching a guy get shanked in prison, and then an earthquake happened,” Audrey Thomas, a sophomore vocal music education major at UCO, said. “I was a little freaked out, and I couldn’t move for a second.”
Thomas said she didn’t know what was happening until her roommate yelled “earthquake!”
“He ran out, and I just kind of sat there and was like, ‘I don’t know what to do in the case of an earthquake, so I’m just going to sit here,’” she said. “It was my first earthquake, and I didn’t care for it.”
The epicenter of the large quake was about five miles southeast of Sparks, Okla., a small town in Lincoln County. Early Saturday morning, another large quake registered a 4.7 magnitude and was recorded with an epicenter about eight miles northwest of Prague, Okla., roughly five miles directly south of the Saturday evening’s quake.
“We do know that this earthquake occurred on a ‘strike-slip’ fault,” Paul Caruso, a geophysicist at the United States Geological Survey’s National Earthquake Information Center, said. “That means that the movement was in a side-by-side motion, it wasn’t up and down like a ‘thrust’ fault.”
Caruso said that the USGS was not able to pinpoint the exact fault line the quake originated from, but that it’s possible it came from the Wilzetta fault.
“The Wilzetta fault is one of a small series of faults that formed during the Pennsylvanian Epoch about 300 million years ago, and it’s believed that these faults have been reactivated,” he said.
Caruso said that faults became dormant as a result of changing plate tectonics.
“The stress and strain has been readjusted so that it isn’t on that main fault line,” he said, “but then, hundreds of millions of years later, that fault is still a weak spot in the crust of the Earth, so if there’s stress and strain in the area, that’s natural the first place that’s going to fail.”
Caruso said the USGS expects aftershocks to continue for weeks, and possibly months.
“We can’t predict earthquakes, and we don’t know how long the aftershocks will continue,” he said. “But we hope that the 5.6 quake was the biggest in the series.”