Morgan Anderson was enjoying a snow day late Tuesday morning in her living room in Sheridan when the shaking started.

"Our front windows kind of rattled and we heard the boom. We thought it must have been thunder," the 17-year-old Anderson told The Times.

Anderson, who was baby-sitting, received a call from a relative who lives just outside the city limits.

"My uncle called and said his whole house was rattling," she said.

The shaking lasted about three seconds, Anderson estimated.

"It sounded like a little low rumble of thunder."

Sheridan police began receiving phone calls from confused residents about 11:30 a.m., Sheridan Police Chief Chuck Bergeron said, adding nearly 10 people reported feeling the shaking.

The La Salle County Sheriff's Office also reported receiving a couple of calls.

Rumors circulated the rumbling was an earthquake, and Anderson said she was continuously checking the U.S. Geological Survey's Web site for any indication of earthquake activity in the area.

She found none.

According to Tim Larson with the Illinois State Geological Survey, there was no indication of an earthquake in Northern Illinois Tuesday.

He added the last earthquake recorded was on Nov. 28 in the southeastern portion of the state, along the Wabash River.

The quake measured a 2.5 on the Richter scale.

Emergency management officials in La Salle County said the cause of the rumbling -- which was felt as far as Seneca -- is undetermined.

"For the moment, we're going to list it as unknown," said Emergency Management Agency Coordinator Mike Jobst.

There were no reports of injuries or property damage.