[A26B]

Originally Posted by Dynomite

I am guessing here but..........I bet those underground caves have everyone in that area wondering who is next. Time to change some construction site inspection rules at the State level (Pre and Post construction). And time to apply new technology to identify and monitor these underground caves.

Just my thoughts......

I don't disagree with you and the technology is more than likely( basically geophysical seismic acquisition like we have used in the oil & gas industry for decades only now much more advanced and no "dynomite").

The problem in Karst areas, lies in knowing just how deep and large the "vug" (underground open area) is plus the overlying rock stress characteristics. Vugs & caves may take from hundreds to millions of years to form, depending on the amount of groundwater and resistance of the rock to solubility & erosion.

The roof collapse of a vug or cave may occur from a few feet thick to dozens or more feet. The roof collapse is not always "right under the surface" as it looks afterwards. The collapse may occur tomorrow or hundreds of years from now. There are so many variables that only the most eminent conditions might warrant preventative measures. So, what do you do if you detect a void space, say 112ft from the surface with only an approximation of rock overburden thickness, area and fracture strength, and empty or full of water? Avoid, build, pier, etc....?

To me, it's a bit like forecasting tornadoes. We are getting better, but seldom do we know exactly when or where until it happens. The certainty is only mother nature knows and ultimately she always has her way.