That Sinking Feeling: Are We at Risk for More Sinkholes?
Geology professor David Nash discusses what causes sinkholes and the best way to avoid them.
Sinkholes seem to be happening with alarming regularity. One in early March
nearly swallowed a school bus. Last month several Corvettes fell into a sinkhole underneath the National Corvette Museum in Bowling Green, Ky., causing thousands of dollars in damage. And, it was around this time last year that a home in Florida was swallowed up by a sinkhole, burying the homeowner alive.
Stories like these can instill fear in people who live in areas where sinkholes are common, but not a lot of people know what makes sinkholes more prevalent in some areas and less in others.
McMicken College of Arts and Sciences geology professor David Nash credits the cause of sinkholes to Limestone. As carbonate rock, like limestone, dissolves, land becomes vulnerable to sinkholes. And since 15 percent of the earth’s surface is made up of limestone, that same percentage is prone to sinkhole development.
There are two types of sinkholes. One occurs when the land dissolves from the surface down, creating a shallow, bowl-shaped hole. The other forms when a cavern develops beneath the surface, causing the surface to collapse.
Nash says water level also contributes to the development of sinkholes.
“If you’re in a period of drought or if you did anything to lower water there is a greater chance of a sinkhole developing,” says Nash. That’s because the support of the rocks is withdrawn when ground water level drops.
Unfortunately, Nash says, once a structure is built, there’s not very much you can do to prevent a sinkhole from forming.
“Sinkholes can happen wherever a structure is built on limestone,” says Nash.
Nash says the best thing to do to avoid being affected by a sinkhole is to get a subsurface investigation and build in an area where the ground isn’t made up of limestone.
“You can build anywhere you want to build, you’ll just spend a lot more on site preparation [if you build on limestone] than you would otherwise,” he says.
Lucky for UC, Nash says Cincinnati is less likely to experience sinkholes because urban and suburban areas take more caution when building and have stricter construction codes.
Read more: UC Professor Ken Tankersley discusses sinkholes in this WCPO story