Did you feel last night's earthquake?

Gaetana Rudolph of McHenry said she was not concerned when her couch skipped forward while she was sitting on it Monday night.

And Frank Tomaszewski said he initially dismissed his wife's claim that an earthquake had caused their McHenry home and its contents to shake slightly as they watched television just before 10 p.m. Monday.

“We had just put the kids to bed. I was watching the news and my wife was reading,” Tomaszewski said. “We had just sat down together and we felt everything move. She asked me, ‘Did you feel that? I think it was an earthquake,' and I said that doesn't happen here.”

Tomaszewski said news reports Tuesday confirmed his wife's theory.

“It was literally a second and a half,” Tomaszewski said. “A couple of back and fourths. If everything hadn't shifted, I would have thought it was just a big firework: you get that feeling in your chest, but we heard no noise.”

The U.S. Geological Survey reported the earthquake with a magnitude of 2.4 occurred at 9:54 p.m., centered just east of McHenry and just west of Lakemoor. Its origin was about 5.4 miles deep.

Earthquakes happen more frequently than most of us are even aware, said Philip Carpenter, a professor of geology and environmental geoscience at Northern Illinois University.

“That is about the smallest you would ever feel,” Carpenter said. “And you almost have to be over the focus to feel it. If you get much smaller you can't feel them, but they are happening.”

The USGS estimates there are 1.3 million earthquakes with a magnitude between 2 and 2.9 each year.

Carpenter said Monday's quake occurred on a previously unknown fault, just like the 3.8 magnitude that shook the Elgin area in 2010.

“In Illinois, there's several hundred feet of glacial deposits on the bedrock,” Carpenter said. “The only clue that there is a fault line there are the small earthquakes that we have.”

Rudolph said Monday's temblor did not cause anything to fall off shelves or walls, unlike the earthquake a few years ago.

“I felt the couch move a little bit but it was no big deal,” Rudolph said.

The shaking from 2010 earthquake would have felt more than 10 times stronger than Monday's earthquake, Carpenter said. The largest earthquake in the state happened in 1906 when a 5.1 magnitude quake was recorded near Rockford, Carpenter said.