Police, residents and experts are baffled by the source of mysterious booms and shaking that have been plaguing the town of Clintonville, Wis., for the past three days, and have caused some residents to flee.
The Clintonville Police Department said they have received over 250 calls about noises from underground shaking homes in the northeast corner of the town near Green Bay, Wis. with approximately 5000 residents.
The mystery is even stumping some of the brightest minds at the University of Wisconsin, who were consulted about whether or not these booms could be related to seismic activity.
"I think we can rule out that standard earthquake activity, [that] some swarm of earthquakes is happening in that region. It also really looks like it's not connected to, say, unusual drilling activity or some other kind of real obvious human induced signal, " Harold Tobin, one of those professors in the Geoscience department at the University of Wisconsin told WKOW.
Tobin headed to Clintonville after he received a call from the Wisconsin Geological Survey office asking for help.
Tobin and a colleague looked at activity on several of the seismometers that sit in the region near Clintonville. He says there is an indication that it is an especially noisy site, but not noisy enough to cause the sounds people there are describing.
Tobin says it does appear the sounds are either coming from the surface of the ground or just underneath the surface. He says that he is just as confused and intrigued as anyone as to what exactly is causing the sounds, and adds that there are other instruments that could be put out in the region where the sounds are to record noise in the air, and also ground vibrations at a higher frequency.
This would help to pinpoint exactly where the sounds and coming from and what their characteristics are.
Residents of the area say that they find the noises and shakes puzzling and troubling.
"They're pretty loud when they vibrate the windows and you can feel the vibration on the floor and on the ground," Verda Schultz told ABC News affiliate WBAY.
The city has so far managed to rule out problems with the water and sewer system, elevated gas levels, area blasting or mining, industrial businesses, and even military operations, WBAY reported.
"I think that right now the greatest possibility is that it is some sort of natural phenomenon. I think that it's a possibility that there is some earth shifting going on underneath the ground that creates those popping sort of exploding popping or vibrating noises that people feel," City Administrator Lisa Kuss said.
The booms and shakes have gotten so bad that they have begun to drive residents from the town.
"Our dog is scared, our neighbors are leaving and stuff, so we decided we are going somewhere else for a while," Dennis Padia said. "It's that loud, and it bothers you. You can't go to sleep."