The 37 wastewater disposal wells to be shut down in north-central Oklahoma, where a 5.6 magnitude earthquake struck this weekend, are just a fraction of the state's total number.
Oklahoma Corporation Commission spokesman Matt Skinner says the wells are among about 4,200 across the state. They're also among the about 700 in a 15,000-square-mile "Area of Interest" created by the commission to address earthquakes in the area near Pawnee.
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.
Skinner said it isn't clear how many wells under the jurisdiction of the Environmental Protection Agency are in an adjacent county.
Saturday's earthquake tied for the largest in the state. No major damage was reported.