What’s behind the earthquakes in Wichita?

All seven of the earthquakes centered in Wichita in 2020 occurred during the past two weeks, with two of them coming hours apart on Thursday. All were relatively in the same area in east Wichita, according to the Kansas Geological Survey.

Is it a sign of something ominous to come?

KGS Senior Scientist Rick Miller doesn’t think so.

By referencing 150-plus years of historical data, he believes the two earthquakes on Nov. 26 and one on Nov. 30, ranging in intensity from 2.4 to 2.7 magnitude in a measurement equivalent to the Richter scale, were foreshocks to the 3.3 magnitude earthquake registered on Tuesday.

Wednesday had a 2.6 magnitude measured at around 9 a.m. and Thursday’s earthquakes — a 2.9 at 2:34 a.m. and 2.7 at 7:36 a.m. — were all likely aftershocks to the 3.3.

The quakes have caused enough of a concern that Miller said he’s had to field lots of questions.

Miller said he could be wrong about the 3.3 being the main event but he wouldn’t expect any additional earthquakes to be above the 3.0 to 3.5 magnitude. That expectation is based on data going back to the 1860s. The oldest data is based on newspaper reports of where and what people said they felt, he said.

The most accurate data on size and location is from 2015 and on when funding helped secure the right equipment to track earthquakes, he said.

“I think there is a large concern level and a lot of it is based on bits and pieces of knowledge, and bits and pieces of folklore and bits and pieces of conspiracy,” Miller said.

Some blame fracking, a process used to extract oil or gas.

But Miller believes a more likely answer to the recent earthquakes are “natural events” that are unfolding on area faults. Earthquakes release energy that brings the faults back to an equilibrium. The energy will then start to build and the same thing will happen again.

He expected this string of earthquakes to be in the “rearview mirror” by Christmas.

Wichita is just west of a “major fault system” known as the Nemaha Ridge or the Humboldt Fault that runs through the center of North America, according to Wichita State University’s geology department chair Will Parcell.

KGS data shows, that in 2016, seven earthquakes occurred in the same area as the seven recent ones. Five occurred between May 9, 2016, and May 12, 2016 and two on Oct. 26, 2016. The magnitudes measured were all between 2 and 2.2.

No one reported feeling them, Miller said. The generally considered threshold for feeling an earthquake is a 2.5 magnitude, he said.

Miller said the actual drilling associated with fracking to extract oil or gas, has been proven to lead to earthquakes in other areas, including Oklahoma. But not Kansas.

”Fracking is not causing earthquakes,” he said. “Not in Kansas.”

However, wastewater injection associated with fracking has changed pressures in south-central Kansas. That pressure correlates with earthquakes in areas like Kingman, Harper, Sumner and part of Sedgwick counties.

“We don’t see that here” in Wichita, he said.

Kansas Corporation Commission spokesperson Linda Berry said the organization has been investigating the string of earthquakes in Wichita but has “no conclusive evidence at this point.”

“There have been no new wells in that area recently,” she said.

The 2020 earthquakes in Wichita have mostly had an epicenter near Greenwich between 13th and Central, according to the KGS. The 3.3 magnitude on Tuesday was a little northwest of those, just east of Bradley Fair and near 21st and Webb.

Thursday’s first earthquake had an epicenter just west of Greenwich at Beech Factory Airport. The other was across the street and more in line with the epicenter of five of the seven earthquakes the last couple weeks, around a residential neighborhood.

The United States Geological Survey, which had 310 reports of people feeling the Wichita’s first earthquake on Thursday and 101 reported feeling the second, showed the epicenters of Thursday’s earthquakes being more than a mile west of where the KGS lists it and with one having a different magnitude.

Miller said both the KGS and USGS data is preliminary but theirs is going to fall closer to being more accurate.

Miller said he didn’t have concerns about the residential areas where KGS data shows a bulk of Wichita’s 2020 earthquakes originated.

A 3.5 magnitude earthquake won’t cause structural damage, he said. It’s enough to crack plaster in old homes but so is expanding and contrasting Kansas clay, he said.

Grandma’s antique salt and pepper shakers could fall off the end of a shelf in a 3.5 but it could also fall if a gravel truck hits a pothole right outside, he said.

It takes a 5.5-plus magnitude earthquake to cause structural damage. The Wichita area hasn’t had an earthquake reach that high in available data going back to 1865, he said.

He said the two highest magnitude earthquakes recorded in Kansas were a roughly 5.2 in Manhattan in 1867 and a 5-5.1 in Sumner County in 2014.

The noise some people associate with an earthquake is affected by the shallowness of the earthquakes, he said. Some believe their dogs can sense an earthquake before it happens. Dogs have a wider range of hearing and can sometimes hear an earthquake before people feel it, he said.

“I fully expect that those (earthquakes) are going to go away too,” he said. “That is the nature of earthquakes.”

This story was originally published December 10, 2020 at 4:47 PM.