An increase in magnitude 3.0 or greater earthquakes in Oklahoma has been linked to underground disposal of wastewater from oil and natural gas production. State regulators have asked producers to reduce wastewater disposal volumes in earthquake-prone regions of the state. Some parts of Oklahoma now match northern California for the nation's most shake-prone, and one Oklahoma region has a 1 in 8 chance of a damaging quake in 2016, with other parts closer to 1 in 20.
Matt Skinner, the spokesman of the Oklahoma Corporation Commission, which regulates the energy industry, said members of the panel's seismicity team were at work and would provide more details "as available."
The area where the quake was centered saw a magnitude 3.2 temblor earlier this week and is on the edge of a region covered by a "regional earthquake response plan" issued in March by the state Corporation Commission, whose goal was the cut the number of earthquakes by reducing wastewater injection volume by 40 percent from 2014 levels.
Oklahoma was late in imposing volume limits in its effort to reduce earthquakes, taking a different approach than Kansas after both states had an uptick in quakes in the first half of this decade. Kansas moved quickly to limit volume while Oklahoma concentrated on the depth of the disposal. Kansas saw a 60 percent drop while the frequency of quakes in Oklahoma continued to climb.