Oklahoma quake prompts shutdown of gas-linked wells – USA TODAY
One of the largest earthquakes in Oklahoma rattled the Midwest on Saturday all the way from Nebraska to North Texas.
Oklahoma regulators on Saturday shut down 37Â wastewater wells connected to oil and gas production after aÂ magnitude-5.6Â earthquake âÂ matching theÂ strongest quake ever to hit the state â joltedÂ north-central Oklahoma.
Some parts of Oklahoma now match Northern California for the nationâs most shake-prone, and one Oklahoma region has a one-in-eightÂ chance of a damaging quake in 2016, with other parts closer to one in 20.
The quake, centered in rural Pawnee County,Â could be felt over aÂ seven-state area, the U.S. Geological Survey reported.
Gov. Mary Fallin saidÂ on TwitterÂ that the shutdown was a “mandatory directive” coveringÂ 725 square miles in Osage County, just northwest of the quake’s epicenter. She saidÂ the Oklahoma Corporation Commission, which ordered the shutdown, was in touch withÂ the Environmental Protection AgencyÂ regarding the emergency measures.
Fallin saidÂ three homes inÂ Pawnee CountyÂ were damaged andÂ that at least three buildings in the city of Pawnee sustained some level of damage. AnÂ inspection of state highway and turnpike bridges also had turned up “very minor issues,” she said.
Pawnee County Emergency Management Director Mark Randell said oneÂ homeowner was treated and released from the hospital afterÂ sufferingÂ a minor head injury when part of a fireplace fell on him as he protected a child, the Associated Press reported. Randell saidÂ building damage in Pawnee wasÂ mostly brick and mortar from buildings dating to theÂ early 1900s.
Pawnee Mayor Brad SewellÂ told KOKI-TVÂ that some sandstones from damagedÂ historicÂ buildings tumbled onto theÂ sidewalk during theÂ quake. Parts of centralÂ Pawnee, aÂ town of aboutÂ 2,000 people, wereÂ cordoned off until the buildings could be examined.
The Pawnee Nation,Â which has its tribal headquarters in the area, declared a state of emergency and said damage to its buildings was so extensive they were being closed pendingÂ further inspection.
An increase in magnitude-3.0 or stronger earthquakes in Oklahoma has been linked to underground disposal of wastewater from oil and natural gas production.Â According to an analysis published by the Tulsa WorldÂ in January, the volume of wastewater disposed climbed 81%Â overÂ six years, coinciding with the stateâs increase in earthquakes.
Since 2013, the OCCÂ has asked wastewater-well owners to reduce disposal volumes in parts of the state.
âAll of our actions have been based on the link that researchers have drawn between the Arbuckle disposal well operations and earthquakes in Oklahoma,â OCC spokesman Matt Skinner said Saturday of the latest directive. âWeâre trying to do this as quickly as possible, but we have to follow the recommendations of the seismologists, who tell us everything going off at once can cause an (earthquake).â
Saturday’sÂ jolt rattledÂ a wide area of the Great Plains, including Missouri, Kansas, Texas, Arkansas, Nebraska and Iowa.
TheÂ magnitude-5.6 quake equals a temblorÂ that struck the town of Prague, in Lincoln County, in NovemberÂ 2011, according to the USGS.
While hundreds of quakesÂ shakeÂ Oklahoma annually, they have rarely beenÂ felt in northeastern Oklahoma, the Tulsa World notes.