February is Earthquake Preparedness Month in Missouri — a time when anyone who might be affected by a major earthquake in the New Madrid Seismic Zone or NMSZ is encouraged to learn more.
The NMSZ extends from northeast Arkansas, through southeast Missouri, western Tennessee and western Kentucky to southern Illinois.
Matthew McKay, associate professor in the School of Earth, Environment and Sustainability at Missouri State University, said a major earthquake along the fault would significantly impact St. Louis, but Memphis would see the most devastation.
As far as any impact to southwest Missouri, McKay said, "we're so far away that any sort of seismic energy would dissipate pretty fast. We'd feel it, but the amount of damage would be pretty limited because we're just so far away."
He said a major earthquake could crack some masonry in southwest Missouri.
In 1811 and 1812, what’s now known as the New Madrid Seismic Zone generated some of the most powerful earthquakes to ever impact the U.S.
An earthquake, estimated today to have been about 7.5 magnitude, occurred in northeast Arkansas on December 16, 1811. According to the U.S. Geological Survey, the second major shock, estimated at 7.3 magnitude, occurred in Missouri on January 23, 1812, and the third happened on February 7, 1812 in Missouri and Tennessee. It said the earthquakes caused the ground to rise and fall, and deep cracks opened in the ground. According to the Missouri Department of Natural Resources, the quakes destroyed buildings, rang church bells hundreds of miles away and briefly caused the Mississippi River to flow backwards. McKay said there are no records to show how the area that’s now Springfield was impacted. But he said Springfield is in a good spot since the ground is rocky, and there’s not much loose soil.
"Sitting on bedrock is really good," he said. "It dissipates that energy, and it doesn't magnify it like, say, river sediment would, so the majority of the buildings in town would be on the lower end of whatever happened."
Today, the NMSZ sees an average of around 200 earthquakes each year, though most are too small to be felt. DNR said experts estimate there’s a 25 to 40% chance of a large earthquake occurring in the next 50 years.
You can find earthquake preparedness tips at sema.dps.mo.gov/earthquake_preparedness.
