Fracking could cause a major earthquake in Oklahoma

Oklahoma was shaken late Wednesday night by two of the strongest earthquakes to hit the state in recent years, the latest in a series of temblors that many researchers believe are caused by the burial of wastes from oil and gas drilling in the state.

The quakes struck 30 seconds apart and had magnitudes of 4.7 and 4.8 on the Richter scale. While considered light, both were centered directly beneath a region in northwestern part of the state near Fairview, Oklahoma, that produces significant amounts of oil and gas. The second temblor was the fourth-largest ever recorded in Oklahoma.