Is atmospheric pressure present underground?
Yes, and it increases with depth the further underground you go. A good way to think about atmospheric pressure is to realize that, here on the Earth’s surface, we are at the bottom of an “ocean” of air. If you go underground, perhaps into a cavern, you add an additional depth of air, just like you would by diving deeper into a pool of water. There’s plenty more about “understanding air pressure” on this USA TODAY resource page.
