One of the largest earthquakes in Oklahoma history rattled the Midwest on Saturday from Nebraska to North Texas, and likely will turn new attention to the practice of disposing oil and gas field wastewater deep underground, the AP reports. The United States Geological Survey said a 5.6 magnitude earthquake happened at 7:02am Saturday in north-central Oklahoma, a key energy-producing region. That matches a November 2011 quake in the same region. No major damage was immediately reported. People in Kansas City and St. Louis, Missouri; Fayetteville, Arkansas; and Des Moines, Iowa, all reported feeling the earthquake. Dallas TV station WFAA tweeted that the quake shook their studios, too.
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. Saturday's quake was centered about 9 miles northwest of Pawnee, Oklahoma. Earlier this week, the same spot, which is about 70 miles northeast of Oklahoma City, saw a magnitude 3.2 temblor.