Sky Quakes, Broken Gear, or Something Else.

[guyfriday]

Not an update or anything, but there have been more negative altitude Earthquakes lately. This was posted today about skyquakes.

Terrifying 'skyquakes' are being heard around the world including the US - and scientists don't know what they are | Daily Mail Online

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.

ok the meat of the story, for me anyway.

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.

So as for now these Skyquakes will remain a mystery, but the negative altitude earthquakes might have been solved to some degree here in this thread.