Windows rattled.

People frantically dialed 911.

Sound familiar? No, it's not Lititz.

It's Manatee County, Florida, where in June residents heard and felt the same kinds of thunderous booms reported in the small Lancaster County town eight days ago.

The mysterious explosion heard in Florida was only one case among 20 reported to police across the country in the last several years, according to the Bradenton Herald newspaper.

Similar phenomena have occurred as close as Dover, Del., the paper reported. And just like those, the booms heard in Lititz on Jan. 12 remain unexplained.

Weird.

Very, very weird.

"It's one of those things people would like an answer for,'' said Randy Gockley, the county's emergency management coordinator. "It's one of those unexplained things.'' In addition to Lititz, the sporadic booms here have also been felt in Elizabeth and Manor townships, Columbia Borough and parts of eastern Lancaster County dating back to Jan. 2.

Several good theories have been debunked.

Was it roadwork near the Lancaster Airport? Blasting at a Lititz-area quarry? A series of small earthquakes? No, no and no.

Was it a sonic boom from a supersonic fighter jet? It depends on whom you ask.

Charles K. Scharnberger, a professor emeritus at Millersville University and expert on earthquakes, has ruled out a quarry blast or earthquake -- both of which would have clearly registered on a seismograph.

"I would think that blasting is enough of a charge that if that many people felt it, I certainly would have recorded a clear signal,'' he said. "I see quarry blasts all the time. Whatever this little thing I saw was, it was not a quarry blast or an earthquake.

"A sonic boom is still the best explanation I can think of,'' Scharnberger said. "The only outfit flying faster than the speed of sound is the military.'' Typically, though, military fighters do not fly exercises over populated areas because of the panic their sonic booms cause below.

Officials at both Harrisburg International and Lancaster airports refuted theories that the noises were caused by aircraft traveling at or above the speed of sound overhead.

"My operations people aren't aware of anything like that,'' said HIA spokesman Scott Miller. "They don't get many supersonic airplanes through here.'' An air-traffic controller backed up his story: "We didn't have any particularly large aircraft going through here -- nothing large enough that would be going that fast or cause something like that.'' At the Lancaster Airport, air traffic manager John Moeller said that if the noise were a sonic boom, many more people than the several dozen who called police would have felt it.

"A sonic boom doesn't fly,'' Moeller said. "When it happens, it happens over a very broad area. Anything that's off the nose of the aircraft is going to feel it. If you feel it in Lititz, you feel it in Neffsville and Lancaster.'' Moeller said the booms heard on Jan. 12 may have been caused by construction near the airport.

Mountville-based Abel Construction Co. is relocating parts of Millport and Kissel Hill roads in a $9.1 million project that will lay the groundwork for a runway extension.

But Bill Mead, the project manager, poked a pretty big hole in that theory. "We haven't done any blasting over there since before Christmas,'' he said.

Jeff Weidman, an accountant who works in Brownstown, suggested the mysterious booms could be "frost quakes'' -- such as the one he and his co-workers felt Monday night.

"It actually felt like something fell on top of the roof. It shook the building quite a bit,'' said Weidman, who works at Detweiler, Hershey & Associates on Oregon Pike.

"We kind of looked out the window to see if anything fell over or if there was an accident,'' Weidman said. "We didn't see anything.'' A frost quake, Scharnberger explained, occurs when a thick layer of ice covering the ground suddenly cracks.

"It can make a loud, sharp banging sound,'' he said.

While that explanation is certainly plausible for the loud boom in Brownstown Monday night, it most likely does not explain what happened on Jan. 12, Scharnberger said.

There was no ice on the ground, and the temperature was above freezing.

"I don't think we had such conditions,'' Scharnberger said.

The mystery continues.

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