Small sensors found in most smartphones and laptops are sensitive enough to detect the movement of moderate and large earthquakes, and could vastly expand the information gathered during seismic events in densely populated cities, new research suggests.
The devices, called micro-electro-mechanical systems (MEMS) accelerometers, measure movement in three dimensions and tell the phone's screen to flip from horizontal to vertical when the phone tilts. In laptops, they detect the motion of falling, and force the hard drive into a safe mode prior to impact.
Given the widespread use of laptops and smartphones containing these devices, researchers at Italy's National Institute of Geophysics and Volcanology decided to test whether the sensors could adequately record earthquake movements. [7 Ways the Earth Changes in the Blink of an Eye]
"Theoretically, any device connected to the Internet with an internal MEMS accelerometer, such as a computer or mobile phone, can become a strong-motion seismic station, and that could be easily used to enormously increase the number of observation points when an earthquake occurs," said study co-author Antonino D’Alessandro.
To test the effectiveness of the MEMS technology, the team attached a MEMS accelerometer -- the same model found in the iPhone 4 and 5 -- to a device used in conventional seismic surveys, and placed both on a vibrating table, that was oscillating at a known rate. They then compared the readings, to determine if the MEMS chip produced the same readings as the conventional technology.
The researchers found the chip did indeed collect data comparable to that of the standard device. This suggests the MEMS chip could gather data during moderate and large earthquakes (those with a magnitude of 5 or greater), as long as the device was near the epicenter of the movement. The team details their findings today (Sept. 29) in the journal Bulletin of the Seismological Society of America.
"The number of victims following a strong earthquake depends mainly on the intensity of shaking, and the speed of rescue operations," said study co-author Antonino D'Alessandro. "A real-time urban seismic network can drastically reduce casualties in urban areas immediately following a strong earthquake, by quickly distributing information about the distribution and intensity of ground shaking."
The chip did not accurately detect small movements, suggesting it would not be useful in small earthquakes, but the researchers noted that MEMS technology is advancing, and might soon be able to deal with subtler movements.
Researchers at Stanford University in California have also recently explored ways to use MEMS technology in seismic networks, and have even begun creating an international network of volunteer internet users called the Quake-Catcher Network.
While such networks are valuable, they may not be possible to create well in poor or remote cities, where fewer residents have Internet access, D'Alessandro noted. As an alternative, the team suggested manufacturers could develop MEMS devices for the sole purpose of collecting seismic data, and distribute them to emergency management teams in earthquake-prone cities. The teams could then deploy the devices to locations as they see fit.
The research group is now testing a new MEMS accelerometer model that they say is 100 times more sensitive than the one currently used in iPhones, which may be sensitive enough to accurately record small-scale earthquakes.