Just four wastewater wells in Oklahoma – where energy companies dump water after completing the hydraulic fracturing process – have caused scores of earthquakes this year, some 30 km from the site, according to a new study by top US universities. The report, published in Science magazine, focused on the Midwestern state, which has produced 45 percent of the country’s magnitude 3 or bigger seismic shocks in the past five years – with the numbers rising rapidly to match the intensification of fracking activities in the area. While hydraulic fracturing, or fracking, – which involves pressuring rock formations with liquid until they crack, and then extracting the oil and gas within – poses an inherent risk of earthquakes, according to the authors, the biggest culprits were the wastewater wells, where the liquids used for fracking are pumped, once a reservoir is opened. “The disposed fluids are capable of contributing to the seismic activity,” Katie Keranen, a geophysics professor at Cornell, and the lead author of the study, told The Oklahoman newspaper. “These wells are capable. That doesn’t exclude anything else from contributing, but we have no reason to think these are tectonic. They don’t match tectonic activity in other areas. It does seem these are just linked to wastewater. Our research focuses on wastewater and shows it is sufficient.” Read more via RT USA.