A Southern Illinois University geologist says the 3.5 magnitude earthquake that struck near West Salem early Monday is not unusual for the region.
The earthquake occurred at 2:05am in northwestern Edwards County, and more than 300 people reported feeling it to the U.S. Geological Survey.
SIU geology professor James Conder said earthquakes of that magnitude occur every few years in Illinois and typically cause little or no damage.
Conder said residents near the epicenter may have experienced shaking similar to a large train passing by, with rattling windows and minor movement inside homes.
He said the earthquake was caused by ancient fault systems beneath the Illinois Basin, including the Wabash Valley Fault System and the LaSalle Anticline System, where natural stresses continue to build.
Although those fault systems are capable of producing stronger earthquakes, Conder emphasized there is no indication Monday’s quake is a precursor to a larger event. He also said the Illinois earthquake is unrelated to the recent powerful earthquakes in Venezuela, despite occurring within days of each other.