Gravity Sensors Can Predict Earthquakes Faster Than Current Methods: Study

Posted: Nov 23 2016, 11:25am CST | by , Updated: Nov 23 2016, 11:30am CST, in News | Latest Science News

 

Gravity Sensors can Predict Earthquakes Faster than Current Methods: Study
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The detection of subtle gravitational changes may offer people a little more time to prepare for a quake

The sensors that detect changes in Earth’s gravity can also offer adequate warning of earthquakes.

A team of international researchers studying data from gravity sensors near the central point of Japan’s 2011 Tohoku earthquake claim that it is possible to detect subtle gravitational changes immediately after the initial rupture and to track an earthquake. This method can predict earthquake faster than traditional methods.

Current earthquake warning systems rely on seismic sensors that measure seismic vibrations called P-waves, which are generated by the earthquakes. P-waves are the first waves from an earthquake to be detected by a seismograph.

When an earthquake strikes, people typically have only a few moments to make a move before the ground starts to shake. Seismic sensors send a signal to an alarm when they detect seismic waves and allow people from a few seconds to one minute to take measures depending on the proximity to the quake. Gravity sensors, on the other hand, can give people a little more time to prepare because gravity waves travel at the speed of light.

 “The gravity signal is almost instantaneous—the speed of light – whereas classical early warning systems are based on the detection of propagating seismic P-waves. Any second saved enables us to stop trains, elevators, nuclear plants, warn people, and therefore to save lives.” Study’s lead author Jean-Paul Montagner, a seismology expert at the Institut de Physique du Globe de Paris explained.

Scientists have long known that subtle changes in gravity occur as soon as earthquake strikes. But whether it could be picked out from all the other background noise, it was not clear.

To find out, researchers examined the data from gravimeter sensors located approximately 500 kilometers from epicenter of 2011 Tohoku-Oki quake and compared it with data obtained from five seismic stations in the same area. Then, they looked at gravitational measurements taken over 60 days prior to the earthquake and those from the day before to see if it was possible to isolate gravitational signals from all the other background noise. Looking at the data, researchers found that they are able to detect a small blip that stood out amongst the noise of other natural events. The signal was strong enough to confirm a quake had occurred.

The initial outcomes of the study are promising. But further research is needed to understand whether a network of gravity sensor works faster than existing seismic sensors and can truly offer people more time to prepare for an earthquake.

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Hira Bashir covers daily affairs around the world.

 

 

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