SOUTHINGTON — There are more questions than answers about a loud noise that was heard in parts of Southington, Cheshire, Meriden and Wolcott on Monday morning. After receiving a flood of calls, fire and police crews searched the south end of Southington but couldn’t find damage or an apparent cause. Experts and government officials contacted Tuesday also couldn’t come up with a reason for the noise. Here are some of the theories:
1. Sonic boom from an aircraft.
The Federal Aviation Administration refused to disclose whether or not supersonic aircraft were in the area Monday morning, deferring comment to the military. Maj. Andrew Schrag, a spokesman for Air Combat Command, said the closest base with supersonic aircraft is 500 miles away.
“Based off of our analysis, there’s no way it could have been an (Air Force) jet,” he said Tuesday. “It couldn’t have been us.”
It’s possible that another branch of the military, such as the Navy or National Guard, was flying a jet in the area, Schrag said.
A representative with the North American Aerospace Defense Command also said the group had no missions in the area at the time the noise was reported.
2. Low-level seismic activity.
The noise and vibrations felt by area residents likely were not from a shallow earthquake, according James Dewey, a research seismologist with the U.S. Geological Survey. Based on the spread of reports, he estimated that the vibrations were felt in an area of 25 square miles. Earthquakes felt for that distance are generally a strength of 2 magnitude or greater, but a station about 20 miles away detected nothing at that time on Monday.
Dewey said there are very shallow earthquakes, but at a low strength they wouldn’t produce the boom heard by residents.
While the nearby station can detect seismic activity of as low as 1.5 magnitude, Dewey said he’d also check with a United Nations nuclear testing monitoring site which measures infrasound. While the agency is looking for clandestine nuclear tests around the world, the data can be useful in discovering seismic activity.
“We lean towards the idea that it doesn’t represent a seismic incident,” Dewey said. “An earthquake that would be large enough to produce a sound over a substantial area, even if it was very shallow, would be in the two range.”
Scientists have speculated that shallow earthquakes not recorded by equipment were the cause of unexplained loud noises in the Northeastern part of the country and along the East Coast, often referred to as “Seneca guns,” according to a post on the U.S. Geological Survey’s website. Loud booms have been heard on the shores of Lake Cayuga and Lake Seneca in New York. Similar unexplained noises have occurred along the coasts of Virginia, North Carolina and South Carolina, as well as coastal India.
More unusual seismic activity that can cause noise is cryoseism, also known as a frost quake. If the ground freezes to a sufficient depth, plate movement can cause cracks and noises. Dewey said it’s more common farther north and he ruled it out due to the lack of sustained cold weather in the area recently.
A meteorite can cause a boom, but according to Bill Cook with NASA’s Meteoroid Environment Office, area residents wouldn’t have been able to miss seeing a fireball caused by the meteoroid’s entry into the atmosphere.
“Those things generally garner a great deal of attention,” he said. “If it’s large enough to create a boom, it would have been visible even in daylight. They probably should have seen something in the sky.”
Most meteoroids don’t cause a crater, so the lack of an impact area doesn’t necessarily rule out that cause for the boom. But Cook had no records of any such event on Monday.
4. Industrial noise or explosion.
Police Sgt. Jeffrey Dobratz said no smoke was observed as crews traveled around town and even drove to high points in the south end. Dispatchers were “swamped” with calls from residents Monday and even into Tuesday but there was little police or firefighters could do.
“Nothing at all, no smoke, no reports of any property damage,” Dobratz said. “We really couldn’t send anybody because we didn’t have an address, just an area of town.”
Most of the companies in the area were closed Monday as well, according to Dobratz.