Friday Rock Repost: Sand Boil
Normally, layers of sand and silt underground bear the weight of whatever’s on top of them through a network of contacts between individual soil grains. During an earthquake, this network is disrupted. But the stuff on top is still there, bein’ all heavy. Wacky hijinks ensue!
If the jiggling sand happens to be wet, all that overburden pressure is transferred to the water. Water, being incompressible, is not happy about being squeezed like this; if it finds a suitable weak spot, it will squirt out. And voilà, a pretty sand boil!
This picture is totally going in my thesis.