3.6 magnitude earthquake confirmed in central Illinois

CHICAGO (CBS)-- A 3.6 magnitude earthquake was confirmed in central Illinois Wednesday, likely caused by the shifting of glacial weight, according to one scientist. 

The earthquake took place at 4:40 a.m.

CBS 2's Laura Bannon said areas along LaSalle County felt weak movement early this morning. 

Waubonsee Community College's Sugar Grove Science Building features an AS-1 seismograph that captured the earthquake data.  

David Voorhees, Waubonsee Professor of Earth Science and Geology, said the quake was "fairly large" for Illinois. He said it was not caused by shifts in tectonic plates and occurred too far north to be related to the New Madrid fault. Tectonic quakes tend to be more powerful, he said. 

The epicenter of the earthquake was reported to be near Standard, Ill., in Putnam County. The New Madrid fault is located in far southern Illinois, Missouri, and Kentucky.  

Voorhees, who is not a seismologist, believes the earthquake was caused by the shifts in weight of glaciers. He said this has occurred in Illinois before, including in 2008. 

The United States Geological Survey reported the quake happened about 4.6 kilometers below ground. 

There were no initial reports of any damage or injuries.