On precariously balanced rocks
https://www.atlasobscura.com/articles/precariously-balanced-rocks?fbclid=IwAR13xksq8-aaQRD8eV9Ry7WN7-QXzya59eNUxkAR38v7R6rNaYtqxmepJ6U
I still remember when that asshole father and boyscout son toppled that rock in Utah. Anyway. I never considered that this could be studied to find the absence is seismic activity in a region.