Some people felt them. Some did not. Either way, a couple of small earthquakes rattled the area earlier this week.
The first earthquake, of a 3.7 magnitude, struck on Tuesday and was centered near East Prairie, Mo. A smaller earthquake, registering a 1.7, was also centered near East Prairie on Wednesday.
The area is not immune to earthquake activity, as it sits on the famed New Madrid Seismic Zone.
"Somewhere in the greater New Madrid Zone, and even in the Wabash Valley Zone, we have a couple of earthquakes every week,'' said Harvey Henson, an SIU Geologist working in the Dean's Office in the College of Science as Assistant Dean. "Most people don't feel those at all. But the 3.7 some people felt, especially if they were near the epicenter."
Henson said that with the region sitting on a sizable seismic zone that a big earthquake is expected to happen at some point over the next 50 years, according to the USGS.
"In the next 50 years the probability of a 6.0 earthquake or larger is around 40 percent,'' Henson said. "For something like a repeat of 1811-1812 the probability is somewhere around a 7-10 percent chance."
In 1811-1812, the region was the site of three huge earthquakes that were estimated at more than 8.0. Since that time earthquakes thought to be in the 6.3 and 6.7 range rumbled the region in 1843 and 1895.
"We've had large earthquakes, historically,'' Henson said. "The evidence suggest that they reoccur. We don't know exactly when they will reoccur, but the evidence suggests they reoccur."
With the recent small earthquakes being felt by some in the region, as well as very large earthquakes in Haiti and Chile, Henson said it gives him a chance to educate the public about earthquakes.
"I think it's part of human nature to be afraid of things we don't understand,'' Henson said. "We have some support from the Illinois Emergency Management Agency, and we are going out to schools and civic groups and getting the word out. We talk a little about geology and the science of earthquakes. And we help with the preparedness issue. People can contact us if they want us to come and give a presentation."
And what should you do to be prepared in case a large earthquake does hit the region?
Earthquake Kit:
* Flashlight * First-aid kit
* Battery powered radio
* Bottled water
* Stored food items
Learn your building's safe areas:
* Inside corner of building
* Under sturdy furniture * In supported doorway
Learn your building's dangerous areas:
* Near windows * Near shelves
* Near bookcases, etc.
* Learn the main utility shutoffs
* Secure heavy shelves and appliances
* Memorize emergency phone numbers
During an Earthquake :
* Remain calm
* Do not exit building immediately
* If in a vehicle pull off the road away from falling objects
* If indoors move away from windows
* If out of doors move to an open area away from overhead power lines
After an Earthquake Occurs:
* Remain calm * Watch for dangerous debris
* Shut off gas/water mains
* Evacuate building in safe manner
* Help others who may be injured
* Prepare for possible aftershocks
