Sinkholes are also known as a "swallow holes" because they swallow houses, cars, neighborhoods, and people whole. A sinkhole can be as large as 2,000 feet in both diameter and depth. To give you some idea of how large this really is, the Statue of Liberty is only 151 feet from its base to the top of its torch.
Texas, where I live, is home to sinkholes related to the drilling, extraction and techniques in producing natural gas and oil.
I could not find an exact estimate of the number of sinkholes in the USA per year, but two things are evident. First, the number of sinkholes number in the mid to high 5 figures a year. Second, the number of insurance claims for sinkholes is on the rise. I suspect with fracking, we will see more sinkholes, more insurance claims, and more insurance claims denied.
As it turns out, lawyers get involved in sinkholes, mainly in terms of insurance claims denied or delayed.
Some of the lawyers that handle sinkholes are The Voss Law Firm, Marshall Thomas Burnett, the Merlin Law Group, the Corless Barfield Trial Group, and the Nation Law Firm just to name a few. You can find more on Google.
The point is that this area could be developed into a type of national niche law practice that can be highly targeted. And, an exciting practice at that.