Antigravity? Do rocks float?

[ASGuy]

@DSeid

Note that “sinking earth” is the basis of granular convection. As the smaller bits get around the bigger bits and sink into the spaces under the bigger bits they inexorably prop up the bigger bits into the spaces the smaller bits left behind.

Okay, I’ll go with granular convection. Perhaps I should be happy there are no freeze/thaw cycles where I live to aggravate granular convection. On the other hand, we do have plenty of very small earthquakes.

And I forgot about pumice.

[Darren_Garrison]

@ASGuy

On the other hand, we do have plenty of very small earthquakes.

Seems like a good culprit to me. A very small earthquake could cause very slight liquefaction in loose soil, and “plenty” of them would add up.

[ftg]

If freeze/thaw is ruled out I’d go with wet/dry cycling. Some soils really expand and shrink based on changes in moisture content and that’s enough to shift rocks.