Facing a six-year barrage of increasingly large earthquakes, Oklahoma regulators are effectively ordering the state’s powerful oil-and-gas industry to substantially cut back the underground disposal of industry wastes that have caused the tremors across the state.

On Monday, the state Corporation Commission asked well operators in a Connecticut-size patch of central Oklahoma to reduce by 40 percent the amount of oil and gas wastes they are injecting deep into the earth. The directive covers 411 injection wells in a rough circle that includes Oklahoma City and points northeast.

It follows a February request that imposed a 40 percent cutback on injection wells in a similar-size region of northwest Oklahoma.

The actions significantly increase the effort to rein in the quakes, which the commission has long tried to reduce one well or a handful of wells at a time.