On an average day in Land O'Lakes, Florida, the ground opened up and swallowed a house whole.
The house was the latest victim of one of the many sinkholes plaguing Florida. According to Florida news outlet WFLA, two homes, a boat, a driveway, and a portion of the road was sucked into the ground.
Video taken at the scene on July 14 shows a home quickly collapsing downward, as if hit from above by an invisible bulldozer. A front exterior wall fell into a gurgling pit of mud, revealing the family's living room. While no one was hurt from the incident, the home was destroyed and several others had to be evacuated.
Comparatively, the affected families got off lucky. In 2013, one sinkhole near Tampa opened up in the middle of the night under the bedroom of Jeff Bush, killing him. The same sinkholes reopened again in 2015, though this time no one was hurt.
Land O'Lakes is in Pasco Couty, north of Tampa. The new hole is 225 feet wide and 50 feet deep—the largest in the region's history.
A Deadly Phenomenon
"Sinkholes are probably the least studied hazardous phenomenon on our planet," said Hofstra University geology professor Robert Brinkmann. Brinkmann has been at the forefront of understanding how sinkholes impact urban and suburban areas, so much so that he even wrote a book about it in 2013.
He explained that Florida has a landscape uniquely susceptible to sinkholes. The state sits over carbonate rock made of mostly limestone and dolostone.
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Sinkholes usually form gradually. When finer, sandlike sediment sits over bedrock it can fill the cracks and holes. As the sandier sediment creeps downward, the land sitting atop it subsides. As the void grows, or if top sediment is suddenly washed away by water, sinkholes can form (and are often filled with water).
Occasionally, underground cavities can form under surface rock. When the cavity expands so much that the surface can no longer support its weight, it suddenly collapses.
A 2015 survey conducted by the Florida Department of Environmental Protection mapped Florida's vulnerability to sinkholes.
Researchers found that the southern tip and northernmost regions of Florida had anywhere from 500 to 1,000 feet of overlaying sediment to act as a buffer between the surface and the state's tumultuous limestone. Areas near the northwestern coast, however, were found to have as little as 10 feet of rock acting as a buffer. This coincided geographically with where sinkholes in Florida are typically reported.
The study's maps allow state planners to accurately zone residential and commercial areas. Once property is built over an area susceptible to a sinkhole, little can be done to stop a potential collapse, so avoiding the area altogether is the only sure way to avoid the disaster.
Are Sinkholes on the Rise?
Florida's 2015 study found that, in addition to the natural geological events that create sinkholes, certain human activities—such as water pumping and ground loading—may make the Earth's surface more vulnerable.
It's a misconception, says Brinkmann, that sinkholes are increasing in number, at least in Florida. As suburban areas expand into regions that are more prone to sinkholes, the number of incidences of damage simply becomes more likely.
While human activity can make the rate at which a sinkhole forms more rapid, he notes, it rarely causes geologically formed sinkholes to appear. Sinkholes have appeared in urban areas; however, these often result from the collapse of unstable infrastructure.
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In 2013, Mother Jones magazine reported on a town in Bayou Corne, Louisiana, that was being swallowed by a sinkhole. The town is home to a massive industrial complex where hydraulic fracturing (fracking) has taken place, leading some to speculating that the rapid increase in underground drilling had created the sinkhole.
Brinkmann didn't know of any studied link between fracking and sinkholes and said more research would be needed to confirm the link.
While some states keep individual databases of sinkhole incidences, no national databases are available.