The Oklahoma Corporation Commission has ordered the closure of seven oil and gas wastewater disposal wells in an effort to prevent further earthquakes in two areas.

This is part of ongoing efforts by the commission to mitigate the impact of underground wastewater disposal on seismic activity.

The regulator said on Thursday that it had asked operators to close four disposal wells in the Byron/Cherokee area, and wants to see cuts of 25 to 50 percent in disposed volumes for 47 other wells. In the Medford area, the commission called for three disposal wells to cease operations and 19 other wells to cut disposed volumes by 25 to 50 percent.

These changes will result in a net volume reduction of 47 percent in the Byron/Cherokee area and 42 percent in the Medford area. In addition, another 67 disposal wells have been placed on notice to prepare for possible changes to their operations.

U.S. government scientists said in April that the increase in earthquake activity in the central and eastern United States since 2009 is linked to the disposal of oil and gas wastewater by injecting it into deep wells.

Around the same time, the Oklahoma Geological Survey officially recognized for the first time the link between oil and gas wastewater disposal and the record number of earthquakes recorded in the state in recent years.

State Rep. Cory Williams claimed last week that pressure from the oil and gas industry is hampering effective regulation of the industry.

“The problem is we’re being totally reactionary as opposed to proactive,” Williams told the Associated Press. “We wait for a seismic event, and then we react to it, which is an abysmal policy for handling something that can cause catastrophic damage to property and/or life.”