By Travis Mounts
Local earthquakes are becoming more common in south central Kansas, but they aren’t becoming old news.
An early morning earthquake woke up a number of residents in Sumner and Harper Counties on Sunday. The quake struck at 3:46 a.m. After initially being classified as a 4.0, it was later downgraded to a 3.7. That followed a number of smaller earthquakes on Wednesday – as many as a half dozen.
If you think this recent surge of activity is out of the ordinary, you are correct. Longtime residents say they’ve always worried about other things, such as damaging storms.
Kathy Lamb and her family live in western Sumner County but just a few miles east of Sunday’s epicenter. Sunday’s quake hit about 1-1/2 miles west of Freeport in far eastern Harper County. Last week’s quakes were mostly scattered around Harper County.
“I guess I’m used to tornadoes,” she said. “Earthquakes are new. I’m not sure what to do.”
Lori Drouhard lives north of the epicenter with her family by Danville. She teaches in Harper, and she and her class felt several of Wednesday’s earthquakes. Sunday’s temblor woke her up as well as her husband.
“We haven’t had one that strong, but it’s enough to shake the bed and wake you up. We’ve had a few pictures fall off the wall,” she said.
Like many people, Drouhard wonders what is behind the increase.
“There’s a lot of speculation going on,” she said.
One expert told the Star-Argosy what isn’t behind the increase – fracking.
Rex Buchanan is the interim director of the Kansas Geological Service. He said there is not evidence that hydraulic fracturing or “fracking” - the fracturing of rock by a pressurized liquid – is responsible.
But that doesn’t mean what’s happening is natural, either.
“It’s not too early to guess (the cause). Everybody’s guessing. It’s too early to guess with any certainty,” Buchanan said by phone from Washington, D.C.
Traditional oil and gas production could be responsible, he said. There is waste water byproduct from nearly all oil and gas production, and often there is more waste water than oil produced. That waste water often is pumped into the ground.
“That kind of disposal has been going on in Kansas for decades,” he said. That kind of production has increase in the past few years in southern Kansas, too.
It could be natural, too. Buchanan said there are natural fault lines in the area, although none of them are major ones that are named. An increase in activity doesn’t mean a new fault line has been discovered, either. Buchanan said most new fault lines are discovered during oil and gas exploration. An earthquake or an increase in seismic activity does not normally lead to the discovery of unknown fault lines.
“There’s no question there’s faulting in that area. There aren’t any named faults,” he said. “There has always been activity in that area in the past, but not at this level.”
Lamb raised a question about something she found on a map – Bluff City-Valley Center Anticline. It turns out, that’s a real thing but not a cause of quakes.
Buchanan said an anticline is a hump-shaped structure in the subsurface.
“You can think of it like the back of a turtle,” he said.
Earthquakes became a topic of local interest following the November 2011 central Oklahoma quake that was felt throughout this area up toward Kansas City and into Missouri. Last December, a 3.8 quake on the Sumner-Harper county line shook local residents again.
Kansas ranks among the five least-active states for earthquakes. The largest quake occurred in 1867 near Wamego. Known as the Manhattan earthquake, it was a 5.1 or 5.5, depending on which account you read. It knocked down chimneys as far away as Kansas City, and created a two-foot wave in a nearby river.
While scientists continue to look for concrete evidence between fracking and earthquakes, anecdotal evidence indicates some kind of connection. North Dakota has seen much more fracking that Kansas but has seen minimal changes in seismic activity. That could be due to differences in the ground itself.
In Oklahoma, many people believe fracking is behind the increase in quakes there. A study in the journal “Geology” said the injection of waste water into wells 1-2 miles deep could have cause the 2011 earthquake.
But the Oklahoma Geological Survey has said natural causes were behind the earthquake.