Bloomberg - Scientists have linked Oklahoma’s biggest recorded earthquake to the disposal of wastewater from oil production, adding to evidence that may lead to greater regulation of hydraulic fracturing for oil and gas.
The 5.7-magnitude quake in 2011 followed an 11-fold bump in seismic activity across the central U.S. in recent years as disposal wells are created to handle increases in wastewater from hydraulic fracturing, or fracking.
Researchers at the University of Oklahoma, Columbia University and the U.S. Geological Survey, who published their findings yesterday in the journal Geology, said the results point to the long-term risks the thousands of wells pose and shows a need for better monitoring and government oversight.
“There’s not a magic bullet,” Heather Savage, assistant research director at the Lamont-Doherty Earth Observatory at Columbia University, said in an interview. “But if we have more monitoring capabilities, we can watch these things, and catch all the precursor events.”
The earthquake near Prague, Oklahoma, on Nov. 6, 2011, was the state’s biggest and may be the largest linked to the injection of water from drilling process, the researchers reported. The state’s geological office disagreed, and said it was likely “the result of natural causes.” The temblor destroyed 14 homes, damaged other buildings, injured two people and buckled pavement, according to the report.
The wastewater behind the earthquakes came from conventional wells in the Hunton formation, said Katie Keranen, assistant professor at Oklahoma and co-author of the report. The findings are a cautionary note for disposal of the millions of gallons of fluids from hydraulic fracturing, she said.
“It has little to do with where the water comes from,” Keranen said in an interview. “What really matters is how you’re getting rid of the water.”
A spate of earthquakes in the central U.S. in recent years is “almost certainly” man-made, and may be connected with wastewater disposal, U.S. Geological Survey researchers said a year ago. For the three decades until 2000, seismic events in the nation’s midsection averaged 21 a year. They jumped to 50 in 2009, 87 in 2010 and 134 in 2011.