What Caused Giant Sinkhole? Geologists Weigh In - KLTV.com - Tyler, Longview, Jacksonville |ETX News

7/6/05-Smith County

What Caused Giant Sinkhole? Geologists Weigh In

For 11 days, the giant sinkhole in Smith County has been a mystery to those who see it up close.

And we've been asking the same question most people want to know: What caused FM 724 to cave in?

"We're less interested in a cause at this point," Larry Krantz, public information officer for TX-DOT's Tyler office, said. "We mainly want to find out what's, we want to diagnose what's under our road here, what's off the right-of-way."

But Certified Petroleum Geologist Raymond Woodward, of Tyler, says the cause is important.

"I would think that in order to rebuild the road, it would be important to have some idea of the causative mechanism here," he said.

Especially since sinkholes the size of the one in Smith County are rare in East Texas.

They're usually found in Florida and Kentucky, where a thin layer of soil sits on top of a thick layer of limestone. Over time, rain water dissolves the limestone, causing the pavement to collapse.

However, in Smith County, dissolving limestone may not be the culprit.

"We've heard a theory that it was water-sand," Krantz said.

"Essentially, what's going on out there, by some mechanism, is something is carrying the subsoil away," Woodward said.

Causing the road surface to fall.

Fearing the sinkhole was causing a nearby oil rig to lean, workers have spent the past few days taking it down to move it to another location.

TX-DOT officials will not say whether drilling for oil led to the sinkhole. But Woodward says it's "an interesting coincidence... not to be ignored."

"Because something changed out there in the last several months," Woodward said.

Although, he says, the underground conditions may have existed decades or even hundreds of years ago.

As of today, the sinkhole was 105 feet wide. That's five feet wider than it was yesterday.

Julie Tam, reporting. jtam@kltv.com

 

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