Sebastien Guenneau, 37
Sebastien Guenneau sees no reason to fight Mother Nature when you can hide from her. The French mathematician has developed an “invisibility cloak,” which will protect buildings from the shock of earthquakes.
Despite the fact that earthquakes are generally caused by slippage in fault lines deep underground, it is actually the surface shock waves that are most destructive to buildings. The “cloak,” which Guenneau has developed with a two other researchers, Liverpool University’s Alexander Movchan and Stefan Enoch from Marseille’s Fresnel Institute, is actually a series of giant plastic rings buried in the ground around the foundation of a building. In the event of an earthquake, these rings would redirect the destructive surface waves around the building, keeping the structure stable and safe. They need to be large. To protect the Eiffel Tower, for example, the radius of the rings would need to range from 30 to 60 meters and they would be about 1 meter thick.
Think of a building like a cork in water; the bigger the waves, the more the cork will bob up and down. When an earthquake’s surface waves hit the foundation of a building, it causes a similar motion. “You might end up with a collapse if the wave is strong enough,” explains Guenneau. But if the building’s foundation is surrounded by Guenneau’s rings, the rings will move and the building will stay stable.
The building becomes much harder to protect, however, if the earthquake is too close. The building must be a few hundred meters away from the epicenter of the earthquake for the rings to be effective. “If the building stands on top of epicenter I can’t think of any design to protect it,” says Guenneau.
The cloak doesn’t eliminate the surface waves, it simply redirects them. Once they’ve passed through the rings the elastic energy is restored on the other side. Guenneau imagines these rings will be used to protect important structures, such as schools or government buildings. He also envisions the rings being used as anti-vibration devices in smaller-scale structures like cars, airplanes and boats.