Not to go off topic, but why do sinkholes always seem to be nearly perfectly round? Just like crop circles. oo-wee-oo
Sorry. I’ve been off “visiting” & a whole bunch of the dummies are right off the reservation. I came to a post about the *GOP* “cracking up” & lost it. I’m still hysterical.
I think it’s because water collects under the surface and begins to pool, until it “eats” through enough to make it collapse
Gravity. I believe they naturally form domed ceilings while being undercut, like you see in caves with large rooms formed by rockfalls. When it all finally gives way you have a circle.