A large part of southeast Louisiana is slowing sliding into the Gulf of Mexico, according to a recent report from the American Geophysical Union.
Researchers have known for decades that the southern part of the state is sinking (related news: "New Orleans Sinking Faster Than Thought, Satellites Find" [June 1, 2006]).
But the latest findings show that a large egg-shape area about 250 miles (400 kilometers) long and 180 miles (290 kilometers) wide is also gradually oozing into the Gulf.
"This whole section is moving south-southeast and pulling apart from the rest of the country up in the Lake Pontchartrain region," said lead study author Roy Dokka, executive director of the Center for Geoinformatics at Louisiana State University in Baton Rouge.
"It's actually crumpling down at its toe, down south at the bottom of the Gulf of Mexico." (See a Louisiana map.)
Reporting in the December 2006 issue of the journal Geophysical Research Letters, Dokka and colleagues note that the speed at which the region moves is equivalent to that of a glacier—little more than a couple millimeters a year.
Timothy Dixon, a study co-author and professor of geology and geophysics at the University of Miami in Coral Gables, Florida, says there is no need for panic.
"Based on current rates, it would take thousands of years for that process to have any serious effects," Dixon said.
"It just means that New Orleans will [have an elevated] risk of flooding."
Gooey Bedrock
Much of southern Louisiana—which sits on the Mississippi River Delta—was built up over thousands of years by sediments from the river.
Unlike solid bedrock in other parts of the country, this area of the state sits on what Louisiana State's Dokka calls "goo" that is very unstable.
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