A new way to detect quakes
Two teams of scientists have tested a revolutionary way of detecting earthquakes, using the same cables that provide high-speed internet.
Usually earthquakes are detected using seismometers. These are special sensors that measure the movement of the ground. More than 70% of Earth is covered in water, so a lot of earthquakes happen under the ocean. However, creating a network of seismometers on the seabed would be extremely expensive – the cost could be more than £500 million.
A team led by Giuseppe Marra of the National Physical Laboratory in the UK, and another team led by Dr Philippe Jousset from the GFZ German Research Centre for Geosciences, decided to try something new, using fibre-optic cables. These are the cables that provide high-speed broadband and they are buried underground or lie across the sea floor. Marra’s team tapped into a few of these cables at different points across the globe. They sent a beam of light along them and then monitored the light at the other end. If there was a disturbance, such as a small earthquake, the light beam was distorted (bent out of shape). The scientists could work out how strong the earthquake was by measuring the distortion.
Although less sensitive than seismometers, a network using existing internet cables could cover a vast area of the seabed much more cheaply than placing lots of seismometers on the ocean floor, says Marra.
However, since many of these fibre-optic cables are owned by internet and communication companies it will be up to them to decide whether to allow scientists to use them to create an earthquake-detection network.