CHICAGO (BNO NEWS) — An unusual earthquake rattled Chicago on early Wednesday, seismologists said, but there were no immediate reports of damage or casualties.

The earthquake, which had a magnitude of 3.8, struck about 38 miles west-northwest of Chicago at a depth of 3.1 miles. It happened at 3.59 a.m. local time.

A seismologist at the United States Geological Survey (USGS) called the earthquake “very uncommon” for the area. Wednesday’s earthquake was the strongest since June 2004 when a 4.2-magnitude earthquake struck close to Chicago. Another earthquake, a 3.0-magnitude, happened in 1985.

No damage was immediately reported following the earthquake, which was felt as far as Iowa, Indiana, Michigan and Wisconsin.

“We have had numerous calls from citizens that they felt the earthquake,” a spokesman for the Chicago Police Department said. The spokesman, who did not feel the earthquake himself, said no damage had been reported.

The earthquake was initially reported as a 4.3-magnitude, but the USGS later revised the magnitude.