Thinking about "sinkholes"

I just received this from USA.Gov.   Although our Community is subject to such calamities, we still need to be aware and be vigilant--the first and foremost rule in Staying safe:

If you heard recent news reports about a devastating sinkhole in Florida, you may be wondering how this type of event occurs.  According to the U.S. Geological Survey (USGS), sinkholes are most common in karst terrain, or regions where the rock below the land surface is soluble. When water from rainfall moves down through the soil, the rock begins to dissolve, creating spaces and caverns underground. If the underground spaces get too big, a sudden collapse occurs. About 20% of the United States is susceptible to sinkhole events, but the most damage tends to occur in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania. Detailed geologic mapping, which defines areas of soluble rock at the surface and subsurface, can help educate land planners and policy makers about sinkhole risk. If you know that you live in an area underlain by soluble rock, check your property for holes in the ground or cracks in your structure's foundation. Learn more about the science of sinkholes from the U.S. Geological Survey.