App to Detect Earthquakes

Shaking a smartphone can help you pinpoint your parked car, discover a good diner and then pay for your meal. Now, scientists have shown that a jiggling, GPS-equipped phone could someday deliver an early warning of earthquakes.

Earthquake early warning systems depend on the time delay between two sets of seismic waves. The first set, called P waves, often delivers a sharp jolt. The most damaging shaking comes from slower surface waves, called S waves. For cities built far from powerful faults, distant seismic instruments stationed on the hazardous faults can detect the P waves and send an alert before the S waves arrive. The warning may be only a few seconds to a minute, but that’s enough time to stop trains and surgeries and for people to find cover.

For major earthquakes, those of magnitude-7 and larger, GPS sensors in smartphones can also provide up to several seconds of warning, according to a study published April 10.

The researchers tested the system with computer modelling, not in the real world, though they plan to launch a pilot project in Chile this year.

The GPS warning system is deceptively simple: If the GPS receivers from just a few phones suddenly lurched in one direction, that’s probably not an earthquake. But if a few thousand phones all move at once, then the motion is likely from a sudden seismic jolt. (During a major earthquake, the earth may jump horizontally and/or vertically by several feet.)

The phones can determine the location and magnitude of the earthquake from the amount of surface movement and then send out a warning.

Minson hopes that if enough volunteers joined in, a smartphone network could provide an early warning in remote areas of the world where smartphones are popular but earthquake warnings are non-existent. Scientists at the U.S Geological Survey are already monitoring Twitter for earthquake keywords, which provide early confirmation of their instrumental data.