I did know that, Doc. (Life is a wonderment....)
Then the question of why earthquakes make a booming sound.
We have had a few small earth quakes that have caused the police to respond to neighboring towns due to the BOOM sound and a few homes have shaken and had very small damage. Strange but as people call the police over the noise, it is only 2-3 homes effected and the next door neighbors never felt a thing.
Interesting question for me for the last 5+ years. Police scanner reported dozens of calls about a huge bombing sound, the police went down a road with just a show of lights to see if this was a prank of some kind. Nothing was found but 3 miles away 4 homes had been damage to their foundations. not adjacent but sort of random in a one block area.
What the heck was this, the area with the damaged homes had not heard no Booms, just the house shake. The Area that had heard the Booms had no damage.
Local papers said there had been a very small earth quake, we Yankees do not believe a word of this, Yes we are built on Granite rock but, we also know there are huge areas full of 200 years of garbage that can get crazy with methane if not vented properly.
Sonic booms have a reason, the same kind of booms coming out of nowhere are another thing.