WHAT WAS THAT BOOM IN CAPE TUESDAY?

What was that boom heard by some in Cape Girardeau Tuesday around 12:30 p.m.?

We know what it wasn't, but we aren't sure what it was. The loud noise and rumbling was heard and felt in Cape Girardeau as many people ate lunch.

Was it an earthquake?

Dr. Haydar Al-Shukri, director of Southeast Missouri State University's Center for Earthquake Studies, said he couldn't say. The seismograph on campus is down for repairs. But he checked the Internet and didn't see any reports of earthquake activity. He said a tremor might show up on reports today.

Well, was it a blast?

Tower Rock Stone Co. near Scott City has been blasting recently, causing loud noises about 5:30 p.m. But the person answering the phone said the quarry wasn't blasting Tuesday.

Maybe it was Lone Star Industries Inc. "No," said the person who answered the phone. But he heard the same loud noise. "Sounded more like an air blast," he speculated.

An airplane flying at a supersonic speed can cause a sonic boom. To a person on the ground, it might sound like a clap of thunder. It can damage plaster walls and break windows. But Greg Chenowith with the Cape Girardeau Regional Airport said a sonic boom was very unlikely because air speeds are highly regulated in the United States.

Folks at the Cape Girardeau City Hall heard the noise and dismissed it as thunder. But weather observers at the airport said no thunder was recorded at that time.

Cape Girardeau police got a couple of calls questioning the boom. They also had no answers. Neither the Cape Girardeau Fire Department, the Jackson Police Department nor the county emergency operations office received any reports about the mystery boom.