Just over two years http://bestbuynowcost.top/maps/sitemap1.html where to buy accutane online review Florida's peninsula is made up of porous carbonate rocks such as limestone that store and help move groundwater. Dirt, sand and clay sit on top of the carbonate rock. Over time, these rocks can dissolve from an acid created from oxygen in water, creating a void underneath the limestone roof. When the dirt, clay or sand gets too heavy for the limestone roof, it can collapse and form a sinkhole. Sinkholes are caused naturally but they can be triggered by outside events.