TYLER, TX (KLTV) - University of Oklahoma scientists say they have linked Oklahoma's biggest earthquake to the underground injection of wastewater from oil production.
The 5.7 magnitude earthquake hit near the town of Prague, Oklahoma in 2011.
The study says that wastewater disposal injections and hydraulic fracturing can affect the pressure along fault lines, triggering earthquakes.
East Texas has seen nine earthquakes in just the last year, but EOG Resources Vice President Ernest LaFlure says it's not from fracking.
"The areas where the earthquakes occurred in East Texas are along the Mount Enterprise fault zone, which is a very young fault system that's been active for millions of years and has had great seismicity for a very long period of time and the water disposal sites are not near that fault system" said LaFlure. "So we don't think there's a correlation there."
According to LaFlure, companies can only dispose their waste water at state-approved sites.
"If somebody does put any kind of disposal well—and that's for many different industries—directly into a fault zone, that could cause some lubrication of the fault zone and some seismicity but it's a very rare issue," LaFlure said.
Ben McGee with the U.S. Geological Survey says while fracking may not cause earthquakes, it can contribute to them.
"You have to have a fault present to have movement along a fault," McGee said. "But water or fluid injected into the earth in the vicinity of faults or in faults increase the likelihood that those faults will move."
The bottom line? There has to be a fault present naturally for an earthquake to occur, but McGee says only time will tell as to what kind of impact man actually has on those faults.
University of Oklahoma researches along with U.S. Geological Survey say the findings show a need for increased government monitoring and oversight for thousands of disposal wells across the country.