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Luckily this is rare, but items like this have shown up on
the evening's news. Sometimes humans are responsible for
places where the land subsides and/or sinkholes develop.
If large amounts of ground water are pumped from an area
that is composed of a thick layer of fine-grained material
then the land can become more compacted once the water is
removed. In other words, the water keeps the soil from
settling, and once the water is gone, the soil settles --
too bad if there is a house on top.
Some parts of the country are susceptible to sinkholes --
places where the land is underlain by limestone that can
be dissolved by ground water. Also, a house could be
sitting on a salt bed that dissolves, leaving a cavern in
the ground. Some homeowners have become cave-dwellers
overnight! |
