Tsunami Invisibility Cloak

BuzzSkyline writes "New Scientist is reporting on a lab-scale experiment that may lead to a tsunami invisibility cloak, which could protect islands, open-ocean platforms and even coastlines from dangerous waves by effectively making them invisible to tsunamis. The technology is based on the same sorts of negative index of refraction ideas that some physicists are exploring as they try to make an optical invisibility cloak, except that it works with water instead of light."

Comments

Summary's FOS Again

[darkmeridian]

From the article:

But Guenneau cautions that large structures like islands and coastlines are unlikely to become invisible anytime soon, because building the many small islands needed to protect one is such a big job.

"It's crazy - maybe only people in Dubai could do this," he adds, referring to the spectacular artificial islands built there.

Smaller structures such as offshore oil platforms would be easier to protect, he says.

No, we are not going to be protecting islands with this thing anytime soon. And we're not protecting tsunamis from anything because the tsunami will just wash over this suckers unless we build them really, really tall. In which case, we're better off building a freaking wall.

Feasibility

[fiannaFailMan]

Quoth TFA:

But Guenneau cautions that large structures like islands and coastlines are unlikely to become invisible anytime soon, because building the many small islands needed to protect one is such a big job.

"It's crazy â" maybe only people in Dubai could do this," he adds, referring to the spectacular artificial islands built there.

Smaller structures such as offshore oil platforms would be easier to protect, he says.

It's a nice idea but a barrier like this would have to be made of strong stuff. That Asian tsunami a few years ago was able to pick up ten-feet-tall concrete blocks and throw them around like Lego bricks. I'm not sure if I'd want to be sitting downstream of something like this unless they're thinking of making them out of low-lying artificial islands, and in that case I don't know how effective they'd be under a tall enough wave. I'd like to have seen a bit more in the way of diagrams and specifics in TFA.

Re:But what about the other islands

[Thomas M Hughes]

Not exactly. When you're invisible, the light simply passes through where you would have been as normal. You're just not in the way to block those waves anymore. According to the article, the water from the Tsunami mostly goes straight through as if the island wasn't even there. So, if there is a wave that originates from the east, it hits this cloak, the wave will continue it's movement west as if it never hit an island at all. The only ones who would be affected would be anyone who's behind that island, who has been using it to break their Tsunamis in the past.

Having said that, I'm not entirely clear how you can use the device described to protect coastlines. It looks like you need a 360 degree coverage for the device to work. That's not going to work for something like say...China's coast.

What for?

[rrohbeck]

Tsunamis are harmless in open water - their height is on the order of a meter, and there's very little horizontal movement of water involved. They only get tall when they steepen as surf, and are dangerous because of their enormous wavelength (up to kilometers) which means one wave has an enormous volume of water to spill.
All of this won't affect drilling platforms at all, and for islands you need to build a structure all around it - a wall is a lot cheaper. In any case, the low incidence of tsunamis won't encourage anybody to build such structures.
JFWI: http://en.wikipedia.org/wiki/Tsunami#Characteristics