Mysterious 'skyquakes' have been heard around the world for more than 200 years, but scientists have yet to uncover the cause and origin of the bizarre noises.
The sounds could be mistaken for a gunshot or a car backfiring, and have been heard in areas ranging from Belgium and Japan to the Finger Lakes region in New York.
Scientists have tried to uncover where the resounding booms are coming, proposing theories like a meteor exploding in the atmosphere, military exercises, quarry blasts and distant storms or earthquakes.
A strange skyquake has shaken the world since the early 1800s, causing scientists to speculate what could be the cause. They have considered earthquakes, military exercises and storm blasts - but none seem to be the root cause
The first skyquakes were documented in 1811 after people in New Madrid, Missouri heard the strange sounds during a 7.2-magnitude earthquake.
Residents reported hearing 'artillery-like sounds' before or during the quake hit.
Similar noises were then reported during an earthquake in Charleston, South Carolina in August 1886, which were heard for weeks afterward the 7.3-magnittude.
The skyquakes were described them as a 'roaring sound' or 'loud detonations.'
These noises have also been labeled as Lake Guns or Seneca Guns, after Seneca Lake in central New York state which also experienced the phenomena in 1850.
James Fenimore Cooper, who lived in Seneca Lakes during one of these skyquakes, described the experience in his short story 'The Lake Gun.'
'It is a sound resembling the explosion of a heavy piece of artillery, that can be accounted for by none of the known laws of nature,' Cooper wrote.
'The report is deep, hollow, distant and imposing. The lake seems to be speaking to the surrounding hills, which send back the echoes of its voice in accurate reply.'
In the years that followed, the booms were unidentifiable due to their random timing and were unaffiliated with any other natural events.
It wasn't until 2020 that scientists started using seismic data obtained from the EarthScope Transportable Array (ESTA) since 2013.
ESTA is a network of more than 400 seismic stations across the US that detects earthquakes, volcanoes and landslides.
A team of researchers at the University of North Carolina at Chapel Hill cross-referenced ESTA's data with news articles to determine if the noises were caused by earthquakes.
'Generally speaking, we believe this is an atmospheric phenomenon – we don't think it's coming from seismic activity,' Eli Bird who, a researcher who was involved in the study told Live Science at the time.
'We're assuming it's propagating through the atmosphere rather than the ground.'
The researchers speculated that another possibility could be bolides - which are space rocks that explode when they hit the Earth's atmosphere.
Bird said another possibility could be oceanic events like large waves crashing offshore or thunder cracking over the ocean.
'The atmospheric conditions could be such that that gets amplified in a particular direction, or is primarily affecting this localized area,' he told Live Science.
However, despite their efforts, seismologists have still been unable to definitively pinpoint where the skyquakes are coming from.
Residents in 15 Alabama counties were shocked by a boom in November 2017, prompting them to call 911 operators in fear.
The National Weather Service in Birmingham informed people that they couldn't clearly explain the noise and satellite imagery and radar scans didn't show signs of an explosion in the region.
The agency posted on X at the time a similar sentiment that is still being relayed today: 'We don't have an answer, and we can only hypothesize with you.'