Oklahoma’s most powerful earthquake caused by oil production, study says

A new study released this week links Oklahoma’s most powerful earthquake ever to injection of oil wastewater deep underground.

The study published Tuesday in the journal "Geology" looked at a temblor that registered 5.7 and a “prolific sequence of aftershocks” near Prague, Okla., on Nov. 6, 2011.

“We use the aftershocks to illuminate the faults that ruptured in the sequence, and show that the tip of the initial rupture plane is within 200 meters (650 feet) of active injection wells and within 1 kilometer (0.6 miles) of the surface,” the study says.

At least 17 states felt the quake, which injured two people and damaged about 14 homes, The Associated Press said.

The earthquake was the largest ever in Oklahoma, according to the AP.

State experts, however, cast doubt on the study’s findings, telling the news service that there are few places in Oklahoma that can’t be affected by earthquakes.

More from GlobalPost: Day of earthquakes, including biggest on record, rocks Oklahoma

Injecting wastewater from traditional oil drilling isn’t a new process, and that the process causes earthquakes is well documented, Yahoo News reported.

When drilling releases oil from its underground pockets, wastewater can also surface. Oil companies inject that water back into the ground.

“It's almost a lubrication, it can push the fault apart,” Oklahoma University seismologist Katie Keranen said online. “When you do that you lower the stress that's holding a fault together and you can cause it to slip.”

Keranen said the quakes could become stronger and “we don’t know what the maximum size of earthquakes could be.”

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