Floods, hurricanes, storm surges. Does Louisiana need to add tsunami to its list of threats?
A false alert was sent Tuesday to some mobile phone owners advising of a potential tsunami in the Gulf of Mexico, East Coast and Caribbean. When the news media picked up on the mistake, it was the first time some in Louisiana had ever heard about a tsunami threat here.
The Gulf of Mexico was added to the U.S. Tsunami Warning System in 2005. But one expert said the probability that the Louisiana coast will be hit by a tsunami is very low.
"I think in our short life span we will never see one" in the Gulf of Mexico, Juan Horrillo, associate professor at Texas A&M University at Galveston's Ocean Engineering Department, said in an email.
Scientists like Horrillo have studied evidence of massive ancient landslides in the Gulf of Mexico. With the Mississippi River continuing to empty sediment into the Gulf, he said, "a massive underwater landslide in the GOM is considered a potential hazard, although the probability of such an event is very low!"
Such an event, he said, would probably happen once very 5,000 years.
Studies by Horrillo and others at the Tsunami Research Group and elsewhere show massive underwater landslides have the potential to cause flooding in coastal communities, similar to severe storm surge flooding, he said. But researchers think such a landslide needs to be triggered by an earthquake measuring about 7 on the Richter scale.
"Fortunately," he said, "in the GOM, earthquakes of this order are rare ... but we are not exempt."
New Orleans, Horrillo said, is probably safe because it is inland and surrounded by very shallow water. Grand Isle is probably the most vulnerable community along the Louisiana coast because it faces the Gulf, he said.