TOPEKA, Kan. (AP) — The Kansas Geological Survey believes an increase in earthquakes in two southern Kansas counties is linked to saltwater injection after oil and natural gas drilling, according to an agency scientist.
The agency had said in the past that there was a “reasonable probability” that injection wells were linked to an uptick in earthquakes in Harper and Sumner counties in southern Kansas.
On Thursday, KGS scientist Tandis Bidgoli told the Kansas Environmental Conference in Topeka said the two are “definitely linked,” the Topeka Capital-Journal reported.
“We know, at least based on the spatial and temporal relationship between these earthquakes and brine disposal operations in Harper and Sumner counties, that these two are certainly linked,” Bidgoli said. “There’s definitely a strong relationship between the two.”
More than 200 earthquakes have been recorded in Kansas since Jan. 1, 2013. Only five were detected in the previous 10 years.
Bidgoli said the agency wants more study of the relationship between the increased underground pressure and the quakes to know how much the pressure might need to be “dialed back” to reduce seismic activity.
Injection wells, which inject saltwater produced by oil and gas extraction back into the earth, are not the same as hydraulic fracturing, which fractures rock while extracting oil and gas. If scientists determine how increased pressure relates to earthquakes, saltwater injection could potentially be spread out to reduce pressure.
The Kansas Corporation Commission ordered reductions this spring in injection amounts in Harper and Sumner counties, with some limits being reduced up to 60 percent. Commission documents show more than 110 million gallons of water were injected in the two counties in 2014.
The order came after a 4.9 magnitude earthquake in November shook Sumner County.
“That Nov. 12 event, I think is also, perhaps, an induced event,” Bidgoli said.
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