Sinkhole science and how to prevent them

Thomas Warren,

WASHINGTON – A Florida man swallowed into the ground by a sinkhole is a tragic reminder that a sinkhole can form in any place at any time.

“About 25 percent of the U.S. is actually underlain by what we call karst rocks which can dissolve, and we can get sinkholes,” Randal Orndorff, Geologist with the U.S. Geological Survey.

While sudden major rain storms in the western U.S. can create conditions for a sinkhole, generally there are more issues in the higher concentrated rain areas in the eastern and southern parts of the country.

Constant underground movement and rain are major culprits in the process. Over time, the acid from rain erodes rock formations just beneath the surface we live on, causing a cave underground. Just above the cave, but just below the surface, there’s a bit of space that dirt will fill in.

Between us and the dirt, that’s a lot of pressure for the cave to hold up. It, too, has a breaking point.

“When it can no longer sustain itself any longer, the surface collapses into that void,” Orndorff says.

On the flipside, a drought can also play a role in creating a sinkhole.

“Because, as you dry the soil sometimes you lose that adhesive effect of water,” Orndorff says. “If you have a void and no longer have that adhesion of the water it will also tend to collapse.”

There’s no sure-fire method to prevent a sinkhole, however improvements in infrastructure are seen as ways to limit their threat. Researchers are currently working on options they hope will allow them to identify high-risk areas.

“Kind of like a CAT scan or an MRI when you can look into the body,” Orndorff. “We want to be able to look underground so we can see these things before it happens.”

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