Oklahoma was rocked Wednesday night by two of the state’s largest earthquakes in recent years, further fueling scientists’ concern that the continued burial of oil and gas wastes in seismically active areas was courting a much more powerful earthquake.

The two quakes, measured at magnitudes 4.7 and 4.8, struck at 11:27 p.m. in rural northern Oklahoma, directly beneath a major oil and gas production area. The second quake, which came about 30 seconds later, was the fourth-largest recorded in the state. There were no reports of injuries or damage, the authorities said Thursday.

The two quakes followed a series of smaller ones last week that peeled brick facades, toppled columns and caused a power failure in Edmond, an upscale Oklahoma City suburb. Some experts said those quakes hinted at the possibility of a larger shock. FULL REPORT