Oklahoma City-area earthquakes prompt new investigation

Utility regulators and geologists said Thursday they suspect a series of earthquakes in the Oklahoma City metro area — home to about a third of Oklahoma's population — which knocked out electricity to some residents in the wealthy suburb of Edmond, were caused by nearby disposal of wastewater from oil and gas production.

The quakes started Tuesday and continued into Thursday, with at least seven of magnitude 3.0 or stronger being recorded in an area about 4 miles (6 kilometers) northeast of Edmond — about 15 miles (25 kilometers) northeast of Oklahoma City. The largest, a magnitude 4.2 temblor, hit Wednesday night.

No injuries or significant damage have been reported, although two Edmond Electric substations were knocked offline Wednesday, leaving about 1,900 customers without power for about an hour.

The Oklahoma Corporation Commission, which regulates utilities, said Thursday that the most likely cause is the injection of wastewater from oil and natural gas production into disposal wells in the area known as the Arbuckle formation, although there is a fault line in the area.

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