That sinking feeling: sinkholes can happen around here, too
Mon, 04 Mar 2013 22:42:32 GMT —
The gaping sinkhole that swallowed a man from his Florida home last week has been revealed after demolition crews knocked down the remaining walls and began clearing away the debris.
Crews razed more than half the home Sunday, managing to salvage some keepsakes for family members who lived there.
Dr. Rick Peterson a Coastal Carolina University marine science lecturer, says practically the whole state of Florida is built on a limestone foundation, which is basically the remnants of coral reefs.
Peterson says sinkholes happen when acidic groundwater gradually eats away at the underground limestone.
"Once that gets big enough down there it can't support the weight of the land on top of it, all of a sudden the land just collapses and takes whatever is on top of it with it," Peterson said.
Peterson explained that the ancient tectonics of the Grand Strand area caused the city of Myrtle Beach to end up situated over a dome of solid rock.
The limestone, if there is any under Myrtle Beach, is pretty thin.
But Peterson says just a few miles south of Myrtle Beach, in Murrells Inlet and beyond, a much thicker limestone foundation starts showing up underground.
A sinkhole in Georgetown swallowed a building in November, 2011 and while that had a man-made cause - crews pumping water out of the ground as part of a stormwater project - Peterson says the same thing can happen naturally.
"In natural cases, you've just got this rock that starts to dissolve away and can't support the weight on top of it," he said.
The CCU marine science lab has all sorts of sonar devices to detect underground geology on land and offshore.
So, armed with that knowledge, does Peterson think sinkholes like the one in Florida are something Grand Strand residents should worry about?
"My understanding of the underlying geology suggests that we're not in imminent danger, but certainly as you move closer toward Georgetown or farther up toward Little River and farther north, it becomes an ever increasing possibility."
Peterson says the limestone under Florida is many times thicker than it is anywhere on the Grand Strand, which makes Florida's sinkhole problem worse than our area's.
The hole that appeared in Florida last week bottomed out at 100 feet. The thinner limestone layer in our area makes it unlikely that any sinkholes would swallow a building to that depth, he says.
The Associated Press contributed to this story.