Even a weak earthquake can cause tremors hundreds of miles away.
That was the case with the 3.6 magnitude quake originating from Putnam County early Wednesday morning. Shakes were reported by people as far away as Milwaukee and Dubuque, Iowa.
The U.S. Geological Survey says the 3.6 magnitude earthquake was a kilometer, or a bit more than half a mile, south-southeast of Standard, Illinois.
Over 300 people reported feeling the weak earthquake on Wednesday morning, according to USGS research geophysicist Oliver Boyd. That includes reports from Peoria, Princeville, Washington, Edelstein, and Lacon. Boyd said those citizen reports are useful.
"It's important for people to tell us that they felt an earthquake because it sort of substitutes for having instruments. You know, seismometers in the ground everywhere," he said.
Boyd said the citizen reports help the USGS better understand how far earthquake ground motions will propagate in different parts of the United States.
This particular quake didn't occur along a major fault line. Boyd said the USGS hasn't been able to identify a fault responsible for this quake, but that's not uncommon for incidents like these.
"They're pretty rare in the central and eastern United States, and sort of random in terms of where they occur," Boyd said.
The last earthquake of a magnitude more powerful than 3 on the Richter scale last occured in this region in 2013, Boyd said.
Still, powerful quakes aren't unheard of in Illinois. The New Madrid faultline has produced several magnitude 7+ quakes over the past thousand years, including the earthquakes of 1812 and 1813. Boyd said it's important for everyone to be prepared for a powerful tremor.
"To do that, you would get under something sturdy, you drop cover, make sure nothing's gonna fall on your head. And then stay there until the shaking stops," he said.
