Oklahoma Quake Upgraded to 5.8 Mag, More Waste Wells Shut Down

Oklahoma drillers are being ordered to shut more fracking wastewater wells just as the U.S. Geological Survey is upgrading last weekend’s earthquake to a record magnitude.

The Environmental Protection Agency said it has ordered the closure of 17 additional disposal sites under its jurisdiction in Osage County. The move follows the suspension of 37 wells by the Oklahoma Corporation Commission and comes on the same day the USGS upgraded the tremor to 5.8 in magnitude, the highest ever for the state, from 5.6 previously estimated.

Oklahoma regulators had already been limiting the disposal of oilfield wastewater, which scientists have linked to seismic activity, before the tremor that was felt from Texas to Illinois on Sept. 3. The number of earthquakes measuring 3.0 or higher reached at least 890 last year, up from just two in 2008, before the state’s fracking boom started. The USGS has not determined an official cause for the earthquake.

“At this point, we don’t want to attribute it specifically to any phenomena,” George Choy, seismologist at the U.S. Geological Survey, said in a phone interview. “We need to get more data to make sure everything is lined up before we say anything definitive.”

Fracked wells produce large quantities of wastewater, which drilling companies inject into ultra-deep disposal wells. The Oklahoma Corporation Commission, which regulates oil and gas activity in the state, has been issuing restrictions for more than a year aimed at cutting down on the amount of wastewater injected into disposal wells. The measures may raise costs for drillers.

“In $45 oil, every little bit of cost increase makes a difference,” Chad Warmington, president of the Oklahoma Oil & Gas Association, said in an e-mail. “It becomes prohibitively more expensive when you have to truck water for any significant distance versus disposal on the site of your oil and gas production.”

Related:

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• Energy Companies Sued in Oklahoma over Earthquake Damage
• Oklahoma Orders Reduction in Wastewater Disposal after Quakes
• U.S. Seismic Risk Maps Now Include Earthquakes Caused by Humans
• Safety Experts: Oklahoma Quakes a National Security Threat
• Numerous Aftershocks Follow 5.6 Magnitude Earthquake in Central Oklahoma