A 5.6 magnitude earthquake hit just north of Pawnee, Oklahoma early Saturday morning, setting off a chain of aftershocks throughout the region. The city of Pawnee has reported some damage to buildings but no injuries. Photo courtesy City of Pawnee/Facebook
PAWNEE, Okla., Sept. 3 (UPI) -- A 5.6-magnitude earthquake shook Oklahoma Saturday morning, according to the U.S. Geological Survey, tying the record for biggest quake in state history.
The USGS said the earthquake was felt across Oklahoma and into parts of Kansas, Arkansas, Missouri, Texas, Nebraska, and Iowa.
The quake began at 7:02 a.m. and the epicenter was located 8 miles northwest of Pawnee in northern Oklahoma. The USGS reported a smaller earthquake in the same area less than an hour later, measuring at 3.6 magnitude.
The USGS said it is not able to say whether the quake was caused by oil and natural gas drilling in the area, but did say several previous smaller tremors were as a result of drilling. Seismologists are investigating whether that was the case again Saturday.
"Without studying the specifics of the wastewater injection and oil and gas production in this area, the USGS cannot currently conclude whether or not this particular earthquake was caused by industrial-related, human activities," the USGS said in a statement Saturday afternoon. "However, we do know that many earthquakes in Oklahoma have been triggered by wastewater fluid injection. The USGS will continue to process seismic data in the following days and weeks that will help answer this question."
The European-Mediterranean Seismological Centre, which monitors seismological activity across the globe, tweeted Oklahoma has experienced at least five earthquakes in three hours Saturday.
There were no reports of injuries, though the earthquake reportedly damaged a 100-year-old historic building in Pawnee.
"It's an old historical building about 100 years old," Pawnee Mayor Brad Sewell said. "It's still standing but some of the outer layers of sandstone fell, it could be cosmetic damage, we don't know yet."
"An initial survey of the area has revealed some damage, but most structures appear intact," the city of Pawnee said in a statement on Facebook. "We've received no injury reports, thank God. Although downtown buildings appear intact, we've blocked off the downtown buildings until building inspectors arrive later today to examine the structures more thoroughly."
The Pawnee quake ties with a 2011 quake near Prague, Okla., for the biggest earthquake in state history.