The commission, which oversees oil and gas production, has borne virtually all of the political and legal responsibility for curbing the quakes in a state where energy companies wield enormous power. Gov. Mary Fallin has established an advisory panel to research the issue, but conceded only last spring that wastewater disposal wells were the likely cause of the tremors.

Oklahoma’s energy companies have played down and even denied a connection between wastewater and earthquakes. Privately, however, many have voluntarily complied with regulators’ recommendations to reduce the risk of quakes, both out of a sense of public responsibility and a growing concern about liability for quake damages.

Monday’s action could change that. Reducing wastewater disposal inevitably reduces oil and gas production — and profits. Whether the dozen operators of the 23 wells at issue will willingly go along remains to be seen.

The regulators also are pushing the limits of their legal authority in seeking to limit disposal wells that have never been shown to contribute to earthquake activity. A letter explaining the new policy, sent to well operators on Monday, stops short of calling it a directive, stating only that the operators “need to reduce volumes” and thanking them for their cooperation.

The 38 percent reduction, which the operators have been given 60 days to put in place, would reduce the volume of injected wastewater to 30 percent below the level of 2012, when the area was largely earthquake-free.

The area of rising earthquake activity, which runs roughly from Oklahoma City to near Stillwater, was judged at unusual risk of a large earthquake by a South African geophysicist who analyzed the region in an academic paper released in March. The researcher, Chris Hartnady, concluded that networks of faults in the area held the potential for an earthquake of magnitude 6 or greater, and urged authorities to begin educating citizens on disaster preparedness even as they worked to reduce the rate of quakes.

The 40-mile stretch experienced 14 earthquakes of magnitude 2.5 or greater in 2013, but 359 last year. The region is on track this year to exceed last year’s total by 20 percent.