The Oklahoma Corporation Commission has ordered the operators of five oil and gas wastewater wells to reduce disposal volumes by up to 50 percent after two high-magnitude earthquakes in the Edmond area last week.

The link between underground wastewater disposal and the record number of earthquakes recorded in the state in recent years was officially recognized by the Oklahoma Geological Survey last year.

Publishing details of its response on Monday, the regulator said that there are five operating disposal wells in the Arbuckle formation located within 10 miles of the center of the latest earthquake activity. The well within about 3.5 miles of the activity will reduce its disposal volume by 50 percent while the other wells within the 10-mile zone will reduce volumes by 25 percent.

All Arbuckle disposal wells within 15 miles of the activity will also be required to conduct reservoir pressure testing, and operators of wells located 10-15 miles away were advised that future seismic activity might result in an expanded area for reductions to include those wells.

Tim Baker, director of the Oklahoma Corporation Commission’s Oil and Gas Conservation Division, said that the new rules are part of an ongoing process.

“We are working with researchers on the entire area of the state involved in the latest seismic activity to plot out where we should go from here. We are looking not only at the Edmond area, but the surrounding area as well, including the new seismic activity that has occurred in the Stillwater area.”

In early December, the commission ordered the closure of seven oil and gas wastewater disposal wells in an effort to prevent further earthquakes in the Byron/Cherokee and Medford areas.