Last week, an 8.2 magnitude earthquake struck off the coast of Chile, causing landslides and a not insignificant tsunami. Just a week before that, several smaller earthquakes struck Southern California. After the devastation caused by the massive quake that hit Japan in 2011, resulting in a nuclear plant meltdown and even satellites being knocked out of their orbits, there's a growing realization that despite their unpredictability, it's vital to be prepared for the inevitable large earthquakes. French scientists are looking to protect vital infrastructure in areas prone to such earthquakes by building something akin to an acoustic shield to divert a quake's energy elsewhere.
Although some scientists are working on predicting earthquakes, they still occur without much more than a few minutes of warning at best. The team of French scientists are trying instead to just mitigate the damage, especially to buildings that don't react well to violent shaking, like power plants. Starting with cloaking techniques that can bend some wavelengths of light around a target to make them invisible, these scientists wondered if sound would behave the same way. The idea is to build a series of small holes around a city prone to earthquakes that resonate at the same frequencies as the quakes themselves, cancelling out vibrations and keeping the area inside the holes safe. The scientists set up a demo using acoustic waves in soil, and it worked: the acoustic waves deflected energy from their simulated earthquake from a specific target area.
There’s just one problem with deflecting earthquakes with acoustic waves. The energy still has to go somewhere else. So now scientists need to figure out where to divert all that energy where it will do the least amount of damage, but making sure that critical areas like nuclear plants and hospitals remain safe would still be a major improvement.