That lake disappearing is creepy! Some crack in the crust 9must have lots of limestone down there) opened just below it...how far to New Madrid from there?
http://quake.wr.usgs.gov/prepare/factsheets/HiddenHazs/
The St. Louis area is vulnerable, says Riess, because it is close to the New Madrid seismic zone in Missouri’s Bootheel region. The zone is known for the New Madrid earthquakes of 1811-1812, one of which registered 8.0 on the Richter Scale and rang church bells in Boston. http://www.newswise.com/articles/view/503181/