‘Unexplained booms’ heard under Tennessee city in 2013 and 2015 have returned

The “unexplained booms” that terrified an eastern Tennessee city in 2013 and 2015 have returned in the past few days, according to a Facebook post by the Morristown-Hamblen Emergency Management Agency.

“We are sending the reports of booms on to the state. If any additional information becomes available, we will pass that on,” said a statement posted Monday.

Dozens of people have reported the noises since 2013, leading the city -- 95 miles west of Asheville, North Carolina -- to label the subterranean noises an “ongoing series of unexplained phenomena” on Facebook.

On Tuesday, TV station WATE quoted Hamblen County resident Kim Dillon as saying she heard a “boom” about 1 a.m. Sunday and thought it was an earthquake. She and her husband ran outside to see all their neighbors standing in the street, she told the station.

“The first boom was so hard it literally felt like every door upstairs just slammed shut and just literally vibrated the entire house,” she said in an interview with WATE.

Commenters on the city’s Facebook page admitted being scared and said they had heard “huge booms under ground” as many as four times in a day.

Morristown officials began acknowledging the “unexplained booms” on Facebook in 2015, and revealed people had been hearing the noises as far back as 2013, mostly in the winter.

Town officials also noted a pattern had developed: “Precipitation, followed by a drop in temperature or atmospheric pressure, and the unexplained booms return to Morristown.”

Katherine Stone, a geology professor, told WATE the rumblings could be the sound of stone collapsing deep within the region’s limestone-rich foundation.

“Those caves will collapse on themselves, and so we have a series of collapsing caves and of course the large booming noises,” she told the station.

Morristown officials have shared that theory on Facebook, noting the city of 29,000 people sits atop an eroding landscape known as karst, prone to producing sinkholes.

However, that cave-in theory does not explain why the noises only began five years ago, town officials said on Facebook.

“Morristown and Hamblen County have been in a heavy karst for a lot longer than 2013 so it is unclear why the phenomena, if they are truly related to the karst, would have only begun relatively recently,” said the city on Facebook.

This story was originally published February 27, 2019 at 5:26 PM.