While the debate will most likely remain as tumultuous as the act itself, Oklahoma’s government embraced a scientific consensus that earthquakes rocking the state are largely the result of underground disposal of billions of barrels of wastewater from oil and gas wells.
The state’s energy and environment cabinet introduced a website detailing the evidence behind that conclusion, including links to expert studies of Oklahoma’s quakes. The site includes an interactive map that plots not only earthquake locations, but also the sites of more than 3,000 active wastewater-injection wells.
The website coincided with a statement by the state-run Oklahoma Geological Survey it “considers it very likely” that wastewater wells are causing the majority of the state’s earthquakes.
The statement noted the most intense seismic activity “is occurring over a large area, about 15 percent of the area of Oklahoma that has experienced significant increase in wastewater disposal volumes over the last several years.”
As recently as last fall, Gov. Mary Fallin, a Republican, indicated that suggestions of a relationship between oil and gas activity and seismicity were speculation, and they would have to do more research on the issue.
Fallin called the Geological Survey’s endorsement of that relationship significant, and said the state was dealing with the problem.
“Oklahoma state agencies already are taking action to address this issue and protect homeowners,” she said.
Tuesday’s actions met a mixed response from the oil and gas industry and the governor’s critics. The Oklahoma Oil and Gas Association disputed the Geological Survey’s conclusions, saying further study of the state’s quakes remained necessary.
“There may be a link between earthquakes and disposal wells,” the group’s president, Chad Warmington, said, “but we — industry, regulators, researchers, lawmakers or state residents — still don’t know enough about how wastewater injection impacts Oklahoma’s underground faults.”
Nor is there any evidence that halting wastewater injection would slow or stop the earthquakes, he said.
One of the most prominent advocates of stronger action on the earthquake issue, State Representative Cory Williams, a Democrat, said he is happy with the change in what he called the state’s “head in the sand” approach to the quake problem.
Oklahoma oil and gas regulators have taken steps to ensure that newly drilled disposal wells do not create seismic risks. But they said they have no authority to impose a moratorium, and only limited powers to address the existing wells behind the increase in tremors. Neither the governor nor the Legislature has pushed to increase their powers.
In past decades, Oklahomans experienced only about one and a half earthquakes exceeding magnitude 3.0 in an average year. But since a boom in oil and gas exploration began in the mid-2000s, that number has mushroomed. The state recorded 585 quakes of 3.0 or greater last year, more than any state except Alaska, and is on course to register more than 900 such tremors this year.
Most of the quakes result in little more than cracked plaster and driveways, but residents in quake zones say the cumulative damage — to their property and to their nerves — is far greater.
Larger quakes have also occurred. A series of shocks in 2011 exceeding magnitude 5.0 caused millions of dollars in damage. Some seismologists have warned that the state is risking larger and more damaging quakes unless it acts to reduce the number of tremors.