Kansas Geological Survey Suspects Quakes Caused By Oil, Gas Practices
Officials with the Kansas Geological Survey told legislators Monday they suspect recent earthquakes were caused by oil and gas production practices.
Rex Buchanan, interim director of the Kansas Geological Survey, said a byproduct of the drilling process that is disposed of in wells could be increasing seismic activity in the state.
“The scientific and regulatory community is focused on salt water from these disposal wells as a possible cause of the seismicity,” he said.
Buchanan said his agency has discussed the increase with the U.S. Geological Survey and academics, and information points toward a correlation between the tremors and the increased use of saltwater injection from drilling.
Rep. John Carmichael, a Democrat from Wichita, had asked Buchanan about a “reasonable probability” connecting quakes and the use of saltwater injection.
Injection wells are used to force wastewater produced by oil and gas extraction back into the earth. Injection wells differ from hydraulic fracturing, also known as fracking, which fractures rock to extract oil and gas.
“We need to differentiate between hydraulic fracturing, a well completion technique, and saltwater disposal, a production technique,” Buchanan said.
Ryan Hoffman, director of the conservation division of the Kansas Corporation Commission, said saltwater injection is believed to help protect the state’s water resources. Hoffman said Kansas has 16,000 injection wells, including 5,000 that are saltwater. The rest are enhanced oil recovery wells used to separate water from the oil that has been drilled. The water is then injected back into the rock formation to ease future oil production.
Earthquakes in Kansas are occurring with greater frequency.
“Between 1977 and 2012, the magnitude 2.5 or larger, which are physically felt earthquakes, we’ve had 34. And then in the last couple years we’ve had 115,” said Rick Miller, also of the geological survey.
Seismic activity maps show that most of those quakes are in Harper and Sumner counties in south-central Kansas. In these two counties, two magnitude 2.0 or larger earthquakes occurred between 1977 and 2012. Since 2013, however, 138 such earthquakes have been recorded there.
“This seismic activity correlates with an area of increased oil and gas production, and disposal of large volumes of salt water,” Buchanan said.
The Kansas Geological Survey suspects that recent earthquakes are related to saltwater injection by oil and gas producers, but Buchanan said there is “no reason to believe that this seismic activity is caused by hydraulic fracturing.”
Rep. Tom Moxley, a Republican from Council Grove, asked if the recent seismic activity has caused any harm.
Buchanan said that in Harper and Sumner counties, a 4.9-magnitude earthquake in November caused small cracks in foundations and walls of buildings, including minor damage at the grain elevator in Milan.
Determining the exact nature and causes of recent seismic activity is challenging, he said, because Kansas does not have enough seismic activity measuring instruments. Improvements, however, are being made.
In April, the U.S. Geological Survey installed temporary measuring stations in south-central Kansas. The federal agency installed more after the 4.9-magnitude earthquake hit Sumner County. And the Kansas Geological Survey has installed additional stations.
Ashley Booker is an intern with KHI News Service in Topeka, a partner in the Heartland Health Monitor team.