Smartphones and tablets can give early warning on large earthquakes in areas where highly technical and more expensive systems are not in place, said a new research.
The study, led by scientists at the U.S. Geological Survey (USGS), found that the sensors in smartphones could be used to build earthquake warning systems, though less accurate than conventional systems.
The GPS receivers in a smartphone can detect the permanent ground movement caused by fault motion in a large earthquake, said a study published in the journal Science Advances from the American Association for the Advancement of Science. NASA’s Jet Propulsion Laboratory, Pasadena, California, was a participant in the study.
Using crowdsourced observations from users’ smartphones, scientists could detect and analyze earthquakes, and send them warnings. “Crowdsourced alerting means that the community will benefit by data generated by the community,” said Sarah Minson, USGS geophysicist and lead author.
The early warning system detects the start of an earthquake and rapidly transmits warnings to people and automated systems before they experience jolts.
“Most of the world does not receive earthquake warnings mainly due to the cost of building the necessary scientific monitoring networks,” said USGS geophysicist and project lead Benjamin Brooks.
In their experiment, researchers tested the feasibility of crowdsourced earthquake early warning systems with a simulation of a hypothetical magnitude 7 quake, and with real data from the 2011 magnitude 9 Tohoku-oki, Japan, earthquake.
However, the results show that crowdsourced warning systems help only a tiny percentage of people in a given area contributing information from their smartphones. If phones from fewer than 5,000 people in a metropolis responded, the earthquake could be detected fast enough to issue a warning to areas farther away before the onset of strong shaking. Cell phones can detect ground motion and warn others before strong shaking arrives.
“The speed of an electronic warning travels faster than the earthquake shaking does,” explained Craig Glennie, a report author and professor at the University of Houston in Texas.
The GPS system could be used to issue warnings for earthquakes of approximately magnitude 7 or larger, but not for smaller, yet potentially damaging earthquakes.
“Crowdsourced data are less precise, but for larger earthquakes that cause large shifts in the ground surface, they contain enough information to detect that an earthquake has occurred, information necessary for early warning,” said study co-author Susan Owen of JPL.