A new study from Stanford University asserts that a swarm of earthquakes in Oklahoma is being caused by the unbridled disposal of saltwater produced in oil wells, and not, as has been asserted, by hydraulic fracturing or “fracking.”

The study’s lead author, Rall Walsh says the state of Kansas can draw the same conclusions.

“The geology doesn’t end at the political border, and the oil and gas production doesn’t end at the political border,” Walsh says. “In our study we do mention that that’s the case and that the earthquakes are happening on the Kansas side of the border.”

 

“We didn’t have the data to extend the study over the border,” Walsh said in an interview. He says Oklahoma regulators were able to provide monthly figures, whereas Kansas officials could only offer annual data.

Walsh says the study pretty much rules out hydraulic fracturing as a trigger for the quakes. The fracking process involves large volumes of water, sand and some chemicals injected at high pressure into oil wells to stimulate production. But Walsh says the numbers point to disposal and not fracking.

“The hydraulic fracturing wells are not the problem,” Walsh says. “The saltwater disposal wells, we think, are making the earthquake problem.”

“About 95% of the water injected in those wells, if not more, is produced water, and the remainder could be hydraulic fracturing flowback water.”

Oklahoma and Kansas have seen a dramatic increase in earthquakes in the last couple of years, which are increasingly seen as being caused by oil and gas production activities and the disposal of produced water.