For hundreds of years, from time to time, people in different parts of the Earth have heard mysterious, eerie rumbling and roaring sounds of unknown origin. It appears that in many cases the noise is not related to earthquakes, but rather to something going on in the atmosphere.
Strange sounds have been reported in many parts of the world. In particular, during the quarantine due to the coronavirus, many similar cases were documented, probably because there was less noise pollution, so the sounds of the environment were heard better.
While many of the rumblings people hear are human-related (nearby construction sites, a large car passing by, or some kind of sonic boom), many reports often cannot be explained by artificial sources.
Some of these unexplained phenomena are related to various natural phenomena such as earthquakes, but the source of other sounds remains a mystery.
There are places around the world where these mysterious sounds are heard regularly. In the Ganges delta and the Bay of Bengal, in Japan, Belgium. Loud impact sounds are heard especially near Seneca Lake in the Finger Lakes region of New York. The sounds are so loud that sometimes windows and doors rattle.
Residents of coastal areas of North Carolina (USA) also often report hearing similar unexplained booming sounds, explanations for which range from distant storms or earthquakes to quarry explosions or even military exercises. Now a panel of experts has decided to find out the truth, according to Live Science.
A team at the University of North Carolina at Chapel Hill used seismic data recorded by the EarthScope Array (ESTA) from 2013 and compared it with news reports from North Carolina, where noise has been reported quite frequently. They did not detect any earthquakes in this region.
“In general, we believe that this is an atmospheric phenomenon. We don’t think it’s caused by seismic activity,” researcher Eli Bird told Live Science. “We assume that the sounds propagate through the atmosphere, and not along the ground.”
For now, the researchers decided to focus on listening to infrasound data (low frequency sound) that the human ear can’t hear. They did pick up signals 1 to 10 seconds long that were associated with the recorded mysterious sounds.
While these signals may indeed be related to observed sonic phenomena, the team says they don’t bring us any closer to unraveling the mystery of the sounds.
Many of these can be sonic booms from planes, storm surges, and even tsunamis intensifying in a certain direction, or the sound of methane igniting from layers of methane hydrate. And there is another interesting version: fireballs are meteoroids that go unnoticed, but still produce a sonic boom in the upper atmosphere.
However, more data needs to be collected at the moment to find the real source of the sounds.