A limit on the injection of saltwater into the ground by oil producers coincided with less intense earthquakes in south-central Kansas, according to a state geologist.
The reduction in the magnitude of earthquakes mirrored the adoption of the Kansas Corporation Commission's injection restraints in March, interim director of the Kansas Geological Survey Rex Buchanan said during a forum at the Kansas Energy Conference in Topeka.
"The consensus seems to be that we've seen a drop off of larger events," he said. "You could very well correlate a drop in activity with the KCC order. There are a lot of variables in play."
More extensive analysis is needed in order to wade through the natural and man-made possibilities, Buchanan said, citing a drop in drilling due to falling oil process and a potential lack of tension along fault lines as other probable factors.
The Kansas Corporation Commission is expected to renew another six months of injection restraints in Harper and Sumner counties, the Topeka Capital-Journal reported.
The injection restraints were inspired by the proliferation of earthquakes in the area. About 125 earthquakes shook Kansas in 2014.
As companies forced saltwater deep beneath the ground's surface, earthquakes in the region became more frequently and rate higher on the Richter scale, Buchanan said.
"The same time we're seeing these dramatic increases in earthquake activity, we also see dramatic increases in saltwater disposal," he said.
But the increase in earthquakes can't be directly linked to hydraulic fracturing, also known as fracking, a method in which water, chemicals and sand are pumped at high pressure into the ground to break rock and to release oil or gas trapped in shale formations, Buchanan added.
At the conference, Gov. Sam Brownback lauded the Kansas Corporation Commission for its work in stabilizing the state's earthquake situation.