( CNN ) -- An early morning earthquake rattled northern Illinois on Wednesday , shaking an area about 50 miles west-northwest of downtown Chicago , the U.S. Geological Survey said . The quake was originally reported as having a magnitude of 4.3 , but the USGS later downgraded it to magnitude 3.8 . It hit just before 4 a.m. CT ( 5 a.m . ET ) , with an epicenter about 3 miles underground . The USGS pinpointed the quake between the towns of Virgil and Sycamore , Illinois . Millions of people felt the temblor , with reports coming in to the USGS from Georgia , Tennessee , Kentucky , Ohio , Indiana , Michigan , Iowa and Wisconsin , as well as Illinois . Members of the public sent more than 10,000 reports of the earthquake to the USGS within the first few hours after it struck . See local coverage of the Illinois earthquake . Several callers to CNN said the quake shook their homes severely , but there were no immediate reports of major damage . Doug Dupont of Belvidere , Illinois , about 70 miles northwest of downtown Chicago , said the quake shook him out of bed and caused a 1-foot-long crack in the wall of his kitchen . `` It was really scary . It felt like a train was going by our house , '' Dupont said . `` This is not California . This is northern Illinois . We are not supposed to get earthquakes . '' Did you feel it ? Tell the world about it . Rex Covington , who lives about five miles west of Elgin , Illinois , told CNN affiliate WGN that the tremor lasted five or six seconds -- and also shook him out of bed . `` I was sleeping and the whole bed was shaking , it was that violent , '' Covington said . `` The whole house shook , '' Walter Mockus of St. Charles , Illinois , told WGN . `` The chimes that hang were all ringing . It was so loud , I thought a plane had gone down . '' The shaking also woke up Sarah Evans , of Elgin , Illinois . She immediately turned to the microblogging site Twitter , where she has 38,000 `` followers , '' to see if anyone else had felt the quake . Evans instantly found others in her area who had experienced the shaking , and says she found them comforting because `` I 'd never felt an earthquake before . '' Read about how Evans confirmed the earthquake and connected with others on Twitter . The Illinois earthquake was mild compared to the one that leveled parts of Haiti last month , according to the USGS . The Haiti quake was about 33,000 times as powerful . Some of the strongest earthquakes ever known to hit the United States took place in the Mississippi River valley in 1811 , 1812 , and 1895 , but Wednesday 's Illinois event was 250 miles or more to the north of those temblors , said Randy Baldwin , a geophysicist with the USGS . `` This is a different area geologically , '' he said , calling Wednesday 's earthquake unrelated to the New Madrid quakes of the 19th century . CNN 's Richard Allen Greene contributed to this report .
NEW : USGS revises magnitude down to 3.8 . NEW : `` It was so loud , I thought a plane had gone down , '' man says . NEW : Quake in Chicago was 3.8 times as powerful . Epicenter was 3 miles from Haiti and 50 miles underground .