Over 22 earthquakes recorded in Ellis, Rooks and Russell counties since June 1

By JAMES BELL
Hays Post

There is no need to rush to buy earthquake insurance, according to earthquake expert and Palco resident Don Steeples, despite the 22 earthquakes that were recorded by the Kansas Geological Survey through Ellis, Rooks and Russell counties since June 1.

The largest was rated a 4.5 on the Richter scale, the scale used to judge the intensity of an earthquake, in Rooks County early Saturday.

But despite the increasing frequency and intensity of late, there is little risk of a more damaging earthquake, Steeples said.

The fault lines that have caused recent earthquakes are a feature of the geological region called the central Kansas uplift, which is also responsible for the oil found in the area.

“There is a system of faults that run basically from Wichita up through this area and on up all the way through the Black Hills in South Dakota,” he said.

The recent 4.5 earthquake in Rooks County may be the largest residents have felt, but it is not the most significant earthquake known to have hit the area.

While there was no Richter scale at the time, he believes the largest earthquake in the area occurred in 1879, near Stockton, based on newspaper reports.

“If I were going to guess it, in terms of Richter scale, I would guess somewhere probability 4.7 to 5,” Steeples said. “So we know that earthquakes were occurring here before there were any effects from anything that humans have done.”

While the frequency of the earthquakes in the area is unusual, he is not worried about future earthquakes.

“Anytime you get multiple earthquakes in an area, in a month, that is certainly unusual compared to what we saw 30 to 40 years ago,” Steeples said.

The earthquake network Steeples operated in Kansas from 1977 to 1989 recorded about 200 earthquakes.

While the frequency might be increasing, he said the magnitude is limited by geology.

“I would speculate that the biggest earthquake that we could get in this part of the state, with a return period of several hundred years, would be somewhere in the Richter magnitude of 5.5 to possibly approaching 6,” Steeples said. “But certainly nothing above 6.

“I can tell you I don’t have earthquake insurance and don’t intend to buy earthquake insurance,” he said.

While western Kansas might be off the hook for a large, damaging earthquake, Steeples said an earthquake with a rating of around 6 on the Richter scale is possible around Manhattan every 200 years or so, but anything larger is unlikely and he does not expect a magnitude 7 or stronger earthquake to ever occur in Kansas.

“That is based on the maximum length of the faults that are present in the subsurface,” he said.

With earthquake intensity 6 or below, damage to structures is extremely limited when using frame construction, which is common in the area.

“The same thing that you build a building to withstand a 100 mph wind is the same construction that will withstand an earthquake up to a magnitude 6,” Steeples said. “In terms of structural damage that would cause someone to need to rebuild a part of a house, you really don’t start getting into that until you get into the magnitude 6’s in the U.S.”

Even cracked plaster noticed after an earthquake report is not likely a result of any single seismic event.

“It is really difficult to pin the responsibility for a crack in the sheetrock on a particular earthquake,” he said, but instead could be noticed after and attributed to the event.

Steeples obtained a Ph.D in earthquake seismology from Stanford and prior to his retirement served as the McGee Distinguished Professor of Applied Geophysics at the University of Kansas where he specialized in near-surface, high-resolution seismic reflection research, according to his KU bio page.