From 1975 to 2008 the state averaged three earthquakes of magnitude 3 or higher, but as the oil and gas industry began to surge—one out of every six jobs in Oklahoma is now linked to the industry—so did earthquakes, with 20 recorded in 2009, Soraghan writes.
"The link between earthquakes and drilling in Oklahoma has been actively discussed since at least November 2011, when the state was hit by its largest recorded quake," Soraghan writes. "Centered near Prague, the magnitude-5.7 rupture injured two people and damaged more than 200 homes and businesses."
In May, the Oklahoma Geological Survey and U.S. Geological Survey "said the spike in the number of earthquakes meant it was much more likely that the state could suffer a damaging earthquake of magnitude 5.5 or greater," Soraghan writes. "The joint announcement said deep injection of wastewater was a 'likely contributing factor.'"
Local and state officials can no longer ignore the issue, but still temper their remarks. "Max Hess, a county commissioner in Grant County, which had 135 quakes last year. He also thinks the quakes are related to oil and gas, which has been an economic boon for the rural county northwest of Oklahoma City," Soraghan reports. "It's been good," Hess said of the drilling, "but it's got its drawbacks."
"The Oklahoma Corporation Commission, which oversees oil and gas in the state, last year adopted what it calls the 'traffic light' approach," Soraghan writes. "Disposal wells in a swarm area within six miles of the center of a quake of magnitude 4 or greater are put in 'yellow light' status. They get special scrutiny. The commission has temporarily shut down at least six disposal wells so they can be brought back into compliance."
A review by EnergyWire found that Oklahoma's seismic activity is spreading north into Kansas, Soraghan writes. Kansas, which had only two earthquakes in 2013, had 42 in 2014, with most occurring near the Oklahoma border, Soraghan reports.