Oklahoma earthquakes linked to oil and gas industry increasing in magnitude and frequency

Oklahoma earthquakes linked to wastewater disposal wells used in oil and gas operations are increasing in frequency and magnitude, Heide Brandes reports for Reuters. On Monday, the state had three earthquakes above magnitude 4.0 and are averaging two earthquakes of magnitude 3.0 per day, with 40 total earthquakes recorded in the past seven days, according to the U.S. Geological Survey.

Prior to the oil and gas boom of 2009, Oklahoma averaged two earthquakes of magnitude 3.0 or higher per year, Brandes writes. In 2014, Oklahoma led the lower 48 states in earthquakes with 585 of magnitude 3 or higher, more than the state had in the previous 35 years combined. The Oklahoma Geological Survey, which originally denied any link between seismic activities and fracking operations, has since said that most quakes are 'very likely' triggered by oil and gas activities.

"The state's oil and gas regulator released a directive this month expanding 'Areas of Interest,' parts of the state that have been worst-hit by the quakes, and adding restrictions for 211 disposal wells," Bradnes writes. "In March, the regulator—the Oklahoma Corporation Commission—also directed 347 wells to reduce their injection depths to above the Arbuckle formation. High-volume injections into the Arbuckle, the state’s deepest formation, have the highest potential for seismic activity, according to the USGS. Twenty-one of Oklahoma’s 77 counties are under the order, and oil and gas drilling operators have until Aug. 14 to comply with reducing injection depth." (Read more)