loud booms in the sky
You have reported on my blog and Facebook page many mysterious booms in April 2018. Thank you for that. I will list here 4 news articles featuring loud booming sounds in the UK and the USA, showing that the cause of this strange phenomenon still remains unknown... And finally I will try to give some possible explanations for these loud but unknown rumblings.

Loud boom remains a mystery for Bellingham residents on April 23, 2018

Plenty of theories were floated on social media Monday night and Tuesday morning about the cause of a large boom that was heard from Everson to Bellingham and west to Blaine around 7 p.m. Monday. According to reports, the boom shook houses, though no reports of damage were mentioned. - Bellingham Herald

Michigan Township rattled by mysterious explosion on April 22, 2018

Some people living in and near Bedford Township in Southeast Michigan have reported hearing a loud "boom" that they say sounded, and felt, like an explosion just before 8:30 Sunday evening. And of course the mystery continues. - 13 ABC

Loud bang shocks residents of in Wirral and Liverpool on April 15, 2018

Dozens of people took to social media to express their shock at hearing a loud bang across Merseyside this morning. The huge boom was heard as far and wide as Bootle and Wirral, with some New Brighton residents saying their homes shook. - Liverpool Echo

Residents of Texas shaken by loud bang on April 6, 2018

Some Rogers residents said their homes were shaken and so were their nerves Thursday night after a loud boom happened sometime after 8:30 p.m. Was it tannerite as stated in the article? - TDT News

Possible causes of mysterious booms

First you should look for man-made sources like jet sonic booms, military and police trainings, underground tunnel constructions, blasting, fire, explosions (e.g., tannerite).

You may also know that earthquakes produce loud booms. So if you live in an earthquake prone area, a fracking area, or near a volcano you may experience these loud rumbling noises.

So when you don't have quakes or volcanoes around, then probable causes are regional thunderstorms, tsunami-like waves breaking off-shore, explosive offshore methane bursts, disintegrating meteors or if you are in the desert some booming sand dunes.

But don't forget that when earth moves and pulls apart in stretch zones, loud booms are created by the air above the areas slapping together. Most of the mystery booms and rumblings are the result of a tearing or stretching Earth. So, I would advise people living along stretch zones to keep a close check on their homes and on the sinking ground around. You may indeed experience an increase in crack and sinkhole formations.