Series of quakes
jolt eastern county
Staff writer
A quartet of barely detectable earthquakes last week struck eastern Marion and western Chase counties — three of them in a span of less than two hours on Wednesday.
The first was a magnitude 2.3 temblor that struck at 10:18 a.m. Nov. 2 in eastern Marion County.
It was followed three minutes later by a magnitude 3.0 earthquake, also in eastern Marion County, six miles east of Marion.
The third earthquake, magnitude 2.8, struck at 12:04 p.m. the same day in western Chase County, although senior scientist Rick Miller of Kansas Geological Survey said it could turn out to have been in Marion County instead.
At 8:35 p.m. Thursday, a magnitude 2.7 earthquake rumbled in eastern Marion County, six miles east of Marion.
Although the quakes were measurable, they were not powerful enough to cause damage.
Quakes of 2.5 magnitude or less usually aren’t even felt.
Typically, damage is caused only by quakes of magnitude 5.5 or greater.
Each whole number on the magnitude scale represents a 10-fold increase in shaking. A 5.5-magnitude is 1.000 times more powerful than a 2.5 quake.
The area where the temblors struck was in the Nemaha Uplift on the western edge of the Flint Hills.
According to KGS, the quakes were three miles deep.
People near the earthquake reported that they and their animals were frightened by what they first thought was a sonic boom followed by three aftershocks.
“We’re struggling with a lot of this,” Miller said. “It’s an area where we have a lot of earthquakes.”
What people feel and hear during an earthquake are rocks that are closer to the surface, he said.
“The faults causing the earthquakes are actually several miles deep,” he said.
The area is averaging four or five quakes a year, but not all of them are forceful enough to be felt. An Oct. 10 quake of 2.5 magnitude five miles south and eight miles west of Marion would have been felt, he said.
“The area is naturally susceptible to earthquakes,” he said.
Miller said it’s thought that many of Kansas’ earthquakes are triggered by wastewater injection from oil production.
There have been 21 earthquakes in Marion County in the past four years.
After being quiet for years, the cities of Hope and Herington have seen frequent earthquakes over the past four years, Miller said.
Hope residents who lived there for years and never felt or heard one are the ones calling, he said.
Lifelong Hope resident Doug Stroda said earthquakes are something the community had not experienced before.
The first one he felt was four years ago.
“It was like an explosion that shook the house,” he said.
Tom Remy, who works in Herington but lives in Burdick, said he had not felt a temblor while working in Herington.
“The only one I’ve felt happened in Cottonwood Falls,” he said.
Another employee who lived about 3 miles west and two miles north of Hillsboro would talk about temblors at work.
“That’s kind of a hotspot,” Remy said.