Lake Michigan earthquakes could happen more than we realize, and closer to the city

A 2.9  magnitude earthquake in Lake Michigan off the North Shore may be only the second such quake recorded in the last 100 years. But that doesn't mean it can't happen again, or closer to Chicago.

Dr. Suzan Van Der Lee,, Earth scientist and professor at Northwestern University, said a possible aftershock was recorded Thursday morning.

"It's definitely possible there was an aftershock this morning, definitely smaller than magnitude 2 or 2.5, so that wouldn't show up in the USGS catalog," she said.

According to the U.S. Geological Survey, the earthquake was recorded just after 2:30 p.m. Wednesday about 12.5 miles off the coast of Kenilworth, Illinois. More than 500 people have reported that they felt the quake on USGS's website, between north suburb like Evanston, Deerfield and Waukegan, and some as far south as Chicago's South Side.

Experts say another quake could happen closer to Chicago, but it's unlikely it would bs stronger than what was felt Wednesday.

"If this earthquake were even closer, probably people would feel similar things," Van Der Zee said.

Another lingering question is whether, since this was recorded in Lake Michigan, could there be more opportunities for earthquakes than we realize?

The answer is yes.

"It's possible that in these rocks we could have other earthquakes, and it could be tomorrow, it could be two years from now, 10 years from now, or 100 years from now," Van Der Zee said. "We don't know."

There were no reports of any damage from Wednesday's earthquake.  If you felt the earthquake, you can report it on the USGS website here. 

CBS News Chicago reached out to USGS to ask if they're looking into the possible aftershock Van Der Lee and her colleagues at Northwestern recorded Thursday morning, but they have not responded.