At least six earthquakes reported in Wichita on Saturday, and largest one in city since 1948
Updated 10 p.m.:
The United State Geological Survey has reported a sixth earthquake in Wichita on Saturday.
The latest was a 2.9 magnitude at 8:39 p.m. with an epicenter southeast of 13th and Rock. All six of the reported earthquakes have been in east Wichita and ranged in magnitude from a 2.5 to a 3.5.
More than 200 people reported feeling the latest earthquake. Most were in Wichita but there were also reports of people feeling it in Texas, Tennessee and Iowa.
The Kansas Geological Survey didn’t show the earthquake as of 10 p.m. It appears there could have been seven earthquakes in all on Saturday when comparing times of earthquakes reported by the KGS and USGS.
Original 4:23 p.m.:
The series of earthquakes centered in Wichita on Saturday included what appears to be the largest in Wichita since at least 1948, according to Kansas Geological Survey senior scientist Rick Miller.
The KGS recorded four earthquakes on Saturday: a 3.0 magnitude at 11:42 a.m., 2.9 at 12:40 p.m., 3.7 at 12:47 p.m. and a 2.7 at 1:18 p.m. The magnitude is a measurement equivalent to the Richter scale.
“Earthquakes have been going on for hundreds of millions of years, and so just because it’s the biggest we have had since (1948) that doesn’t necessarily mean it’s the biggest one ever on this fault,” Miller said.
Before 1977, earthquakes in Kansas were measured with felt reports and often based on accounts from newspapers, he said. Felt reports go back to the 1860s in Kansas. Two earthquakes in 1919 and one in 1948 appear to have been around the mid-3s in magnitude or even as high as the 3.7 recorded on Saturday, he said.
It’s possible a similar sized event happened between 1948 and 1977 that was never recorded, he said.
Saturday’s earthquakes all had epicenters near 13th, east of Webb and west of K-96. It’s the area where the KGS has recorded 13 earthquakes in the last month. Those are also the only earthquakes recorded in Wichita since 2016, when a series of earthquakes were recorded mostly in the same area as this year, according to KGS data. Miller said no one reported feeling the 2016 earthquakes.
During the last month, eight of the earthquakes have epicenters between Greenwich and K-96 and 13th and Central, including the 3.7 recorded on Saturday.
The second highest reported earthquake in the last month in Wichita was a 3.3 magnitude on Dec. 8 with an epicenter near the southwest corner of 21st and Webb, which is between 1 and 2.5 miles from Saturday’s earthquakes. The earthquakes during the last month all appear to fall in a 45-degree line, going from northwest to southeast.
“These earthquakes are showing you the trace of that fault,” Miller said.
The magnitudes aren’t alarming when considering historical magnitudes, he said.
The generally considered threshold for feeling an earthquake is a 2.5 magnitude, he said, and it takes a 5.5-plus magnitude earthquake to cause structural damage.
“These sequences like this are going to happen and eventually they’re going to run out of energy … until some point in the future, maybe 100 years, before it comes active again,” he said. “Predicting earthquakes, predicting stock markets, you are kind of in the same game.”
He wouldn’t be surprised if the earthquakes kept going a little while or stopped now.
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.
The recent earthquakes in Wichita, on the other hand, are part of a natural event on a fault that is releasing built-up energy, Miller said.
The United States Geological Survey lists different locations and magnitudes than the KGS of Saturday’s earthquakes. The USGS also lists a fifth earthquake at 12:52 p.m.
All of the USGS-listed earthquakes have epicenters in eastern Wichita, like the KGS. The USGS recorded magnitudes from 2.5 to a 3.5.
Miller said the data from both is preliminary, but, historically, the KGS data has been closer to actual size and location since the organization has more measuring instruments in the area.
The 3.5 magnitude the USGS reported at the same time the KGS recorded the 3.7 had the most people report that they had felt the earthquake. More than 600 people reported feeling it, with mostly weak to light shaking. The majority of people were in the Wichita area, but people also reported feeling it in Texas, Kentucky and Minnesota.
Moderate shaking was reported in Wichita in two of the other earthquakes. People in other states reported feeling all of the earthquakes centered in Wichita.
Wichita councilmember Brandon Johnson, whose district is just west from where the earthquake happened, wrote on Twitter after the first shaking at around 11:42 a.m.:
“Well that was a biggie! I thought my house was caving in!”
911 emergency communications, which is downtown and roughly 7 miles away from the first earthquake epicenter, also reported feeling it.
“Did you feel that earthquake roll through?” a 911 emergency dispatcher said over the scanner. “We just got shook pretty good.”
This story was originally published December 19, 2020 at 1:39 PM with the headline "At least six earthquakes reported in Wichita on Saturday, and largest one in city since 1948."