Science
7:02 am
Tue March 5, 2013

Tragic Sinkhole In Tampa Sheds Light On Florida's Geological Predicament

The news last week of a Hillsborough County man who disappeared into a sinkhole that opened up beneath his bedroom has sparked a renewed national interest in the Florida sinkhole phenomenon. The incident has grabbed national headlines, and the Associated Press put together a slideshow of "Memorable Florida Sinkholes" that included a post-Hurricane-Frances sinkhole on I-95 in West Palm Beach.

Sinkholes can cause substantial property damage and threaten water supplies.
Sinkholes can cause substantial property damage and threaten water supplies.
Credit Southwest Florida Water Management District

Sinkholes are an ongoing concern for Florida residents and lawmakers. At last week's Town Hall event on Session 2013, sponsored by WLRN and the Miami Herald, panelist Sen. Jack Latvala, R-Clearwater, identified sinkholes as one of the primary factors in property insurance costs in the state. 

"What has exacerbated the problem in our area is that, in addition to hurricanes, we have a substantial problem with sinkholes," Latvala said of trying to get a grip on property insurance costs. "That led to an increase in premiums." (To watch footage of the Town Hall, click here. Discussion on property insurance kicks in around the 48-minute mark.) 

Southwest Florida, where Latvala lives and works and last week's sinkhole incident occurred, is a hotspot for the geological hazard. But sinkholes can and do pop up elsewhere in the state, including Southeast Florida. Maps created by the Florida Center for Instructional Technology in 2008 show a small smattering of reported sinkholes throughout Miami-Dade, Broward, and Palm Beach counties. (Be certain to click on the "zoomify version" to see where the sinkholes were recorded.)

The Sarasota Herald Tribune, meanwhile, used data from the Florida Department of Environmental Protection to create a handy interactive map of reported sinkhole activity in Florida. For an old-school look at Florida's geology, check out this map by the United State Department of the Interior. Created in 1985, it's admittedly dated, but it does offer a clue as to why certain regions in the state -- like Hillsborough County -- are most susceptible to sinkholes. The color-coded map -- which outlines the depth of limestone and surface cover throughout the state -- shows that most of Southeast Florida is at low risk for sinkholes and those that form in the region are shallow and form gradually. 

Sinkholes, according to the Southwest Florida Water Management District, are "one of the predominant land forms in Florida." They can range widely in size, but all "are a result of the dissolving of the underlying limestone." Too much or too little rainfall can contribute to sinkhole formation, as can human activities like pumping out water from the aquifer and building construction.