Magnitude 4.7 earthquake shakes Oklahoma, Kansas
TULSA, Okla. (Reuters) - A magnitude 4.7 earthquake struck northern Oklahoma early on Thursday, rattling residents out of their beds and shaking the ground across a 100-mile (160-km) radius that included the city of Tulsa and the state of Kansas.
The U.S. Geological Survey said the 1:42 a.m. CST (0742 GMT) quake's epicenter was 8 miles (13 km) southwest of Cherokee, Oklahoma.
With a shallow depth of 3.8 miles (6.2 km), it was one of the most-powerful temblors to shake Oklahoma since the strongest one recorded there struck in 2011 with a 5.6 magnitude.
There were no reports of any major damage or injuries, a Cherokee city hall official said. A local emergency management official said bridges did not appear to be damaged in areas around the quake's epicenter.
Still, state's oil and gas regulator, the Oklahoma Corporation Commission (OCC), moved within hours on Thursday to implement additional curbs on the use of saltwater disposal wells that scientists have linked to a sharp rise in seismic activity in the state.
Saltwater, a normal byproduct of oil and gas extraction work that boomed after 2009 following improvements in hydraulic fracturing and horizontal drilling, is injected into deep disposal wells and underground caverns.
"We're getting used these earthquakes, although this was a big one," said Cherokee resident Stacey Siler. "Everyone just shot straight out of bed with this one."
Plenty of people reported feeling the earthquake in Wichita, Kansas, where there were no reported damages, said Van Williams, spokesman for the city. The area has felt numerous quakes in recent years but the one on Thursday may have been the most significant.
"It woke me up," Williams said. "I thought it was a bad dream. It felt like someone grabbed the house and shook it."
Thursday's OCC measures call for two disposal wells near the epicenter to shut and for 23 others to reduce intake volumes.
It also told operators of disposal wells within 10 to 15 miles (16 to 24 km) of quake activity to be prepared for additional rules.
The quake comes about a month after an earthquake with a magnitude of 4.5 struck near the U.S. crude oil hub of Cushing, Oklahoma. That quake occurred just days after regulators imposed new rules to limit the use of saltwater disposal wells in a bid to prevent temblors in the area. It also implemented additional measures after that quake.
(Reporting by Kevin Murphy in Kansas City, Victoria Cavaliere in Los Angeles, Lenzy Krehbiel-Burton in Tulsa, Jon Herskovitz in Austin and Terry Wade in Houston; Editing by Alan Crosby and Sandra Maler)
