A state regulator in Oklahoma said it was proposing new plans for how oil and gas operators work in shale basins given the recent occurrence of earthquakes.

The U.S. Geological Survey reported a magnitude 2.6 tremor struck Helena, Okla., on Tuesday. A magnitude 4.2 earthquake was recorded in Edmond on New Year's Day, about 100 miles south of Helena.

The Oklahoma Corp. Commission's Oil and Gas Conservation District said it was working on plans to respond to recent quakes. The commission's director, Tim Baker, said operators are called on to reduce their well wastewater disposal volumes by as much as 50 percent.

"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," he said in a statement. "We are looking not only at the Edmond area, but the surrounding area as well."

Oklahoma Gov. Mary Fallin last year expressed concern about the increase in the number of earthquakes tied loosely to the oil and gas industry in her state. A USGS study, meanwhile, found the rate of seismic activity in Oklahoma has increased since 2009 at a faster rate than any other time during the 20th century. USGS research found "several lines of evidence" to suggest the increase was tied to oil production activities.

The study found the deep injection of wastewater from well sites had the potential to induce earthquakes.