22 agosto 2013

Árboles engullidos en zona pantanosa de Luisiana, EE. UU.

The Assumption Parish sinkhole swallowed a sizeable clump of tall cypress in less than a minute Wednesday evening, pulling them down in a frothy swirl that roiled the usually placid surface of the year-old, 24-acre opening in the earth near Bayou Corne.

In a dramatic video taken by a parish official, the trees can be seen at first just slightly leaning but, as branches crack, the pace of falling quickens and the trees rapidly recede below the surface amid surging currents.

At one point as the trees are falling, a man can be heard saying, “Oh, that’s a big one.”

The edge collapse, or “slough-in,” occurred about 5:30 p.m. Wednesday on the northeastern rim of the sinkhole between the Bayou Corne and Grand Bayou communities, parish officials said.

The collapse followed one of the hole’s periodic increases in underground tremors and related stirrings of gas and debris know as “burps” earlier on Wednesday, officials said.

The sinkhole has been growing since it emerged from the swamps sometime late on Aug. 2 or early on Aug. 3, 2012, as the suspected result of a salt dome cavern failure deep underground months beforehand.

Scientists have said this growth is expected as the hole seeks a final shape and size, a geologic process that may take years.

Though the watery hole — now approaching some 25 acres in size at the surface with some sections that may plunge hundreds of feet deep — has undergone continuing edge collapses or slough-ins, rarely have such sizeable failures been caught on video.

John Boudreaux, director of the parish Office of Homeland Security and Emergency Preparedness, said he was checking the site Wednesday afternoon because of the burp and related tremors, which have halted work on the sinkhole.

“I was just standing there and I pointed out, ‘Hey, it looks like they’re moving. It looks like they’re moving,” he said.

That is when he turned on his camera, he said.

Boudreaux can be heard in the video telling others with him, “‘Yep, I got it. I got it.’”

He said waves churned up by the collapse flowed to the southwest corner of the levee surrounding the sinkhole and reached the levee top, about 6 feet above the surface of the hole.

The sinkhole had been in a dormant period before the new uptick in activity, Boudreaux said.

He added that a section of trees identified Sunday as also showing signs of sloughing in remain in place and were not pulled down in Wednesday’s collapse.

Fuente: The Advocate

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