Wouldn’t it be great if we could hear about earthquakes in advance? Ideally, we’d get a whole week’s warning, but even a single minute could give you time to get to safety, or at the very least to move away from any rickety structures nearby. Yet early earthquake detection systems – based on a delicate system of accelerometers, sensors and computers – are expensive, and are only in widespread use in a couple of places worldwide.
What’s been overlooked until now, however, are the one billion tiny earthquake sensors we’ve all been carrying around in our pockets.
Most modern smartphones contain GPS and satellite navigation sensors – essentially, slightly less sophisticated versions of what are used in earthquake sensing systems anyway. Scientists from US Geological Survey and several US universities drew on this fact to create a concept for a new type of detection system, which would crowdsource information from lots of phones in an area, to watch for oncoming tremors.
Earthquakes take place when the earth, literally, moves; that movement can be picked up by GPS and navigation systems. If a phone and four others nearby detect a displacement of more than 5cm, the researchers’ “ShakeAlert” model is “triggered”. If the system receives 100 such triggers, an alert is sent out to phones in nearby areas.