Not too long ago, and definitely not too far away, I was peacefully minding my own business, knitting happily away. It had been a thunderstormy kind of evening but had been clearing up so as to not be a dark and stormy night.
A rumbling shook the house. Odd, I thought, how it seemed to echo through the floorboards as opposed to the walls or roof. It seemed to last for long minutes, but in reality was probably only seconds. I chalked it up to a last lingering peal of thunder, even though I couldn’t recall seeing a flash of lightning to accompany it. After a few moments, the rumble shook the house again. Bemusedly, I noted that I had definitely not seen any lightning, so it must have been a train passing. Living near the tracks as we do, trains have become background noise to us, barely remarkable unless the engineer blows a familiar pattern on the whistle.
Musing further on the odd subfloor rumble, suddenly I sat bolt upright. That was no train—there had been no whistle! Sure enough, a quick online lookup confirmed that we had experienced an earthquake.
Of course, it wasn’t the first in the area, nor will it be the last. It’s something I didn’t grow up with outside of hearing how people in California all had rails on their shelves to prevent their breakables from falling during an earthquake there. The first one we personally felt out here didn’t knock anything off the shelf, but the bed jolted as if my rather hefty housecat had jumped on it (when he was nowhere in the room).
I keep trying to pinpoint any strange activity on the part of my pets whenever something like this occurs, with little to no success. Either I have earthquake-proof critters, or their natural behavior is so strange as to be indistinguishable from an earthquake warning. Even my normally feather-headed equines were as placid as plowhorses in the hours leading up to the event. My dog is normally clingy, so there was no noticeable change there. I guess I’m a little disappointed that they’re not standing on their heads or running in circles.
As I tend to do when something new happens to me, I started doing some research. I had been aware of the New Madrid fault and seismic zone in Missouri, and thought it was the closest to us. Imagine my surprise at learning that the Humboldt fault runs not far from here, and indeed Kansas’ largest historical earthquake occurred in the Humboldt Fault Zone. In April 1867, Manhattan, Kansas experienced a 5.1 magnitude earthquake. The tremors were felt over a 200,000 square mile area, and reached as far as Indiana and Illinois.
Researching further and surfing around on the Kansas Geological Survey site brought more nifty new knowledge. They have very sensitive seismometers, able to detect tremors less than 1.0 in magnitude. As a matter of fact, from January to June 2016, they recorded 1,858 earthquakes from 0.0-3.1 in twenty counties. Their website at www.kgs.ku.edu also features an interactive earthquake map and charts of magnitude by month quakes. I was fascinated to find how many earthquakes we’ve actually had in Kansas, and grateful that we rank somewhere near 45th out of 50th in earthquake damage in the US.
As of yet, there isn’t any way to predict when, where, or how strong the next one will be. The nice folks at KGS though, might be on to something. An article at www.phys.org describes the use of a sensor array in the Wellington oil field that can detect increases in subsurface fluid pressure, possibly signaling impending quakes. This could be really helpful in the future. Between 1977 and 2012, only 15 earthquakes greater than 3.0 magnitude were recorded in Kansas. After 2012, more than 100 were recorded in just Sumner and Harper counties.
Wastewater injections from drilling are one reason for the increase in earthquake activity, but they aren’t the sole cause. Shear waves and their rate of travel vary between natural and induced earthquakes, and are one of the areas of study at the Kansas Geological Survey. There’s also a theory that wind turbines also cause earthquakes, but that one seems to be unsubstantiated.
Bottom line is that it looks like earthquakes will be happening more often, and at least for the near future, without warning. Thankfully, we don’t seem to be in a high-risk or high-damage zone here in Marion County. Remember your earthquake safety (stay indoors, in a doorway on the bottom level of your house), and if you happen to hear someone yell “HULK SMASH” during the next one, it’s probably me. Stay safe out there, folks.