Making structures 'invisible' to earthquakes

While making people invisible might encourage all sorts of mischief, making buildings “invisible” to destructive seismic waves could help protect them from damage in earthquakes, say scientists at the Institut Fresnel in Marseille.

Such an “invisibility cloak” could also have applications in the automotive and aviation industries, among others.

The invisibility device would actually be a thin plate with a structure that controls the propagation of seismic waves to deflect them from an object — such as a building — in the center of the cloak. Made with concentric rings composed of different materials, the cloak would act as a metamaterial with properties not found in nature.

While the cloak couldn’t protect against all types of seismic waves, it could reduce the damage caused by surface waves, which are the most destructive during an earthquake. The researchers say putting such a device into practice will require working in collaboration with geologists to adapt it to specific ground conditions.

On a smaller scale, the cloak could do away with unwanted vibrations in the automobile and aviation industries.

In 2008, the same team designed an invisibility cloak against waves, with the same effect but working according to a different physical principle. This wave “cloak” is undergoing large-scale trials, and applications under consideration include facilitating fish breeding in tropical areas and protecting limestone coastlines, such as the white cliffs of Dover.