NJ Deputy Attorney General assigned to the State Department of Environmental Protection from 1986 - 1990. When you buy land on which you plan to build a house, you need to make sure that there are no underground impediments that might cause a sinkhole to develop. Sinkholes are craters which form in the ground, causing things on the surface, such as homes, people, and cars, to sink into them.
Sinkholes can be deadly .
For example, in 1993 a 100 foot wide sinkhole formed under a hotel parking lot in Atlanta. Two people died and numerous cars were destroyed. That sinkhole was 25 feet deep. Before you build, you should have a geologist ensure that your subsurface is in good shape. You do not want to build without ensuring that the surface will remain in tact, and will not collapse into a sinkhole.