By Thomas J. Sheeran, Cross Posted from StarTribune
CLEVELAND — A northeast Ohio well used to dispose of wastewater from oil and gas drilling almost certainly caused a series of 11 minor quakes in the Youngstown area since last spring, a seismologist investigating the quakes said Monday.
Research is continuing on the now-shuttered injection well at Youngstown and seismic activity, but it might take a year for the wastewater-related rumblings in the earth to dissipate, said John Armbruster of Columbia University’s Lamont-Doherty Earth Observatory in Palisades, N.Y.
Brine wastewater dumped in wells comes from drilling operations, including the so-called fracking process to extract gas from underground shale that has been a source of concern among environmental groups and some property owners. Injection wells have also been suspected in quakes in Ashtabula in far northeast Ohio, and in Arkansas, Colorado, and Oklahoma, Armbruster said.
Thousands of gallons of brine were injected daily into the Youngstown well that opened in 2010 until its owner, Northstar Disposal Services LLC, agreed Friday to stop injecting the waste into the earth as a precaution while authorities assessed any potential links to the quakes.
After the latest and largest quake Saturday at 4.0 magnitude, state officials announced their beliefs that injecting wastewater near a fault line had created enough pressure to cause seismic activity. They said four inactive wells within a five-mile radius of the Youngstown well would remain closed. But they also stressed that injection wells are different from drilling wells that employ fracking.
Armbruster said Monday he expects more quakes will occur despite the shutdown of the Youngstown well.