That sinking feeling

I want to quickly talk about sinkholes. First is this article about sinkholes in China.

Chinese sinkholes.

Guatemala City

Sinkholes are generally caused by a few specific things. It may be caused by the gradual erosion of soft, permeable rock or the collapse of an underground cave. Problem with the sinkholes in China and Guatemala City is that they are round and not caused by water. Look at the pictures.

Sinkholes caused by water are not round, they go to wherever the soil has the least resistance. Sinkholes caused by collapsing caves are not round either. The sinkholes in China and Guatemala City are round to the bottom. Having a three story building sink into one makes less sense as prior to construction one should have tested the soil and dug test holes. Just odd stuff.