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GCN : May 2015
PHOTOCREDITHERE 16 GCN MAY 2015 • GCN.COM BY PATRICK MARSHALL EMERGING TECH FOR MANY OF US, smart- phones have become the primary tool for organizing our lives. Scientists at the U.S. Geological Survey are trying to turn them into tools for not just organizing but saving lives. USGS geophysicists are developing earthquake ear- ly-warning systems that can grab data from smartphones and pass alerts to those in the path of a quake’s shock waves. According to USGS geophysicist Sarah Minson, the idea for smartphone crowdsourcing came out of the agency’s work on the ShakeAlert early-warning system that is being de- ployed on the West Coast using data from seismic instruments. A team member suggest- ed using GPS to supplement the data from the agency’s scientific instruments. “It was really pretty sponta- neous,” she said. “People hadn’t really looked at consumer GPS before, prob- ably because the accuracy in terms of your location of GPS in your phone is really quite terrible. But its ability to sense your change in po- sition from point A to point B is really quite good.” In fact, the team de- termined that the GPS available in smartphones is capable of detecting earth- quakes with a magnitude of 7 or greater. Using specific software, a smartphone can transmit an earthquake’s detected location and mag- nitude to USGS, which can then send alerts to others in the path of the shock waves. “You can transmit in- formation at the speed of light,” Minson said. “The damaging secondary waves — S waves — travel about 3.5 kilometers per second. That’s fast but not as fast as the speed of light.” Although the warning might reach people only seconds in advance of the earthquake, those seconds can be critical. “If you get a warning, you can get under your desk and hold on,” she said. “A few seconds is also long enough to stop doing something you don’t want to be doing during an earth- quake, such as a doctor operating on a patient.” Although Minson’s team has proved the viability of using smartphones in an early-warning system — and published their results in the April 10 edition of the American Association for the Advancement of Science’s new journal Sci- ence Advances — there are currently some practical limitations. First, of course, is that earthquakes with a magni- tude of less than 7 cannot be accurately detected using the current GPS in consum- er smartphones. As a result, Minson said, “in the United States, the system would be at most a supplement, augmenting the early-warning system that we are building with scientific instruments.” But she added that many areas of the world have no early- warning system at all, so even the limited sensitivity of smartphones can provide a critical advantage. Another hurdle is that consumer smartphones don’t allow direct access to GPS data. “The hardware in the phone is great, but the OS usually doesn’t let you actually access that data,” Minson said. Therefore, smartphone manufacturers would have to cooperate before volunteers’ smart- phones could be looped into a crowdsourced early-warn- ing system. In the meantime, the USGS team just received funding from the U.S. Agency for International Development for a one- year project to develop a smartphone-based earth- quake early-warning system in Chile. According to Minson, the project will not use crowdsourced data. “These will be phones that we own and dedicate full-time to early warning,” she said. “But it will give us an opportunity go through the exercise, providing the software for the phone, pulling acceleration data off the phone, pulling GPS data off the phone and [bringing] the data back for analysis.” • Early earthquake warnings? There’s an app for that. The ShakeAlert system has been sending warnings like this one to test users’ smartphones since 2012. Now those phones can serve as seismic sensors as well. 0515gcn_016.indd 16 4/29/15 1:10 PM