NOVA - Sinkholes
In a leafy suburb near Tampa, Florida, on February 28, 2013, a giant hole opened up under the bedroom floor of Jeffrey Bush, swallowing him as he slept. His body was never found. Bush was a victim of a sinkhole—a worldwide hazard that lurks wherever limestone and other water-soluble rocks underpin the soil. When carbon dioxide from the air dissolves in rainwater, it forms a weak acid that attacks soft rocks, riddling them with holes like Swiss cheese. Sinkholes can occur gradually when the surface subsides into bowl shaped depressions or suddenly when the ground gives way. These geological hazards have swallowed highways, apartment buildings, horses, camels, even golfers, with monster-size holes cracking the earth from Siberia to Louisiana. Filled with compelling eyewitness video of dramatic collapses, and following scientists as they explore the underlying forces behind these natural disasters, NOVA travels the globe to investigate what it's like to have your world vanish beneath your feet.
