A 3.8 magnitude earthquake on the Richter scale shook homes and buildings in the Vermilion County, east central Illinois and west central Indiana area, including to Crawfordsville, Ind. Thursday afternoon.
According to the United States Geological Survey, the earthquake occurred at 2:18 p.m. (central time) Thursday. The quake was centered about 4 km northeast of Montezuma, Ind., which is about 26 miles from Danville.
“Although a lot of people felt it, there have been no reports of damage or injuries,” according to Vermilion County Emergency Management Agency Director Russell Rudd.
The Wabash Valley Seismic Zone experienced an earthquake with a magnitude of 5.2 in April 2008. It was the largest recorded in the state of Illinois at the time and the early morning quake shook residents in Vermilion County.
East central Illinois is in the range of two fault lines for the Midwest.
The New Madrid Seismic Zone lies within the Central Mississippi Valley from Cairo through southeastern Missouri, western Kentucky, western Tennessee and northeast Arkansas. The epicenter of the zone is located just west and northwest of Memphis, Tenn.
Closer in distance, the Wabash Valley Seismic Zone is located in southeastern Illinois and southwestern Indiana, with its epicenter located between Mt. Vernon, and West Franklin, Ind.
Dick Berg, with the Illinois State Geological Survey in Champaign, said they didn’t feel the earthquake there.
“These little snaps and crackles happen more frequently than you might think,” Berg said. “It’s rocks moving. It’s the earth moving and making adjustments, when an earthquake happens.”
“The whole earth is tectonically active,” he said. “It’s huge plates of the earth that are moving. They move until they snap. It happens at depth.”
He said the 1811 New Madrid earthquake, which was over a 7 magnitude, reversed the Mississippi River flow.
“You’re getting big movement among plates. You get some minor movement in some of the faults...,” he said about earthquakes.
A 3.8 earthquake could cause some minor damage. Other more minor earthquakes have caused roads to crackle a bit or bricks to fall off a building, Berg said.
According to the USGS, there is not one magnitude above which damage will occur. It depends on other variables, such as the distance from the earthquake, what type of soil you are on, etc. That being said, damage does not usually occur until the earthquake magnitude reaches somewhere above 4 or 5.
According to the USGS, an earthquake is the ground shaking caused by a sudden slip on a fault. Stresses in the earth’s outer layer push the sides of the fault together. Stress builds up and the rocks slip suddenly, releasing energy in waves that travel through the earth’s crust and cause the shaking that we feel during an earthquake.