Topeka The state's top geologist said Monday there is no evidence to suggest the recent spike in earthquakes in south-central Kansas is directly related to a controversial drilling technique known as hydraulic fracturing, or "fracking."
But he said it probably is related to a byproduct of oil and gas production, whether fracking is used or not, which is the massive amount of saltwater that comes out of oil and gas wells and is later injected into disposal wells farther below the surface.
"To be absolutely clear, we have no reason to believe that this seismic activity is caused by hydraulic fracturing," said Rex Buchanan, interim director of the Kansas Geological Survey.
He also said there appears to be no correlation between the quakes and the times when drilling companies are engaging in "fracking" operations. But he said there does seem to be a correlation between the increased number of quakes and the increased use of injection wells to dump the saltwater that comes out of the drilling process.
"While we have been disposing of saltwater in disposal wells in Kansas for decades, today's horizontal wells are generally more productive in terms of oil and saltwater than traditional vertical wells, thus requiring more high-capacity wells to get rid of saltwater," Buchanan said.
From 1977 to 2012, he said, there were only 34 earthquakes in Kansas that were strong enough to feel. But there were 115 such quakes in 2013 and 2014.
During that time, there was also a big increase in both the number of injection wells in Sumner and Harper counties and the volume of saltwater being stored in those wells.
He also said the agency would need about half a million dollars a year in additional funding to beef up and operate a permanent network of seismic monitoring stations to get better data about where and how the quakes are occurring.
Buchanan and other state officials briefed the House Energy and Environment Committee about the recent spike in seismic activity, especially in Sumner and Harper counties where oil production has also increased in the last two years.
Those quakes have become a source of growing concern in the area, especially after one temblor in November in Sumner County that registered 4.9 in the Richter scale, the largest quake ever recorded in Kansas.
That's still considered light by geological standards, enough to cause objects on a shelf to shake and rattle. But the increased frequency of the quakes, especially in a state that had barely seen any since monitoring began in 1867, has raised public concern, and some residents have even reported property damage.
"We were seeing some locations, particularly in Harper County, where people were reporting small cracks in foundations and walls," he said.
Buchanan said that for many years, there was very little monitoring of seismic activity in Kansas because there was so little to monitor. But since 2013, when activity began to increase, both his agency and the U.S. Geological Society have set up a temporary monitoring network in order to pinpoint when and where the quakes are occurring.
From the data collected so far, he said, the U.S. Geological Survey now believes there is a fault line below the surface that runs diagonally from southwest to northeast in Sumner County, south of Conway Springs.
If it can be shown that the quakes are related to injection wells that are too close to a fault line, Buchanan said, the state would have several options for responding, such as reducing the volume of those wells and limiting the locations for new permits.