Global positioning system technology is pervasive. It’s embedded in cameras, smartphones, tablets and other sensor technology. Virtually all sectors of the federal government use GPS for one reason or another — conducting field surveys, managing land and resources, mapping pollutants and responding to emergency events.
Researchers from the National Aeronautics and Space Administration’s Jet Propulsion Lab and the Scripps Institution of Oceanography at the University of California, San Diego have taken existing GPS technologies and developed a prototype system that warns people of hazards from earthquakes, tsunamis, severe weather and flooding. By adding small, inexpensive sensors from popular electronic devices to GPS technology developed by the geophysical community, researchers were able to significantly improve officials’ response to natural disasters.
When an earthquake begins, the first movements — known as P waves — are not damaging, says Angelyn Moore, research scientist at JPL. "We use GPS and accelerometers to sense that motion in the very first moments, as the earthquake is starting, and gain information about the future arrival and intensity of the damaging S wave."
Thanks to GPS-based systems, warning times for a large earthquake at the southern San Andreas Fault in California could be anywhere from 30 seconds to 2 minutes. This could give people enough time to get under desks or move away from large structures, such as overpasses. Emergency personnel could take safety precautions, such as stopping trains, shutting down large gas valves or unloading elevators at the nearest floor, Moore explains.
“We’ve shown that including GPS reduces the time necessary to arrive at an accurate estimate of the earthquake magnitude,” Moore says. But she points out that the technology is not an earthquake prediction system. “Prediction would be if we could determine in advance a location where a damaging earthquake will occur. Unfortunately, earth science has not yet uncovered a way to do that.”
Was That Your Phone or the Earth?
The U.S. Geological Survey is testing GPS algorithms for the ShakeAlert earthquake early warning system, which the agency developed in collaboration with several universities in California and Washington. Doug Given, a geophysicist with the USGS, says that, as JPL researchers learned, GPS technology gives a more accurate estimate of the magnitude of an earthquake, but it’s not without challenges.
Researchers at the California Institute of Technology, one of the developers of ShakeAlert, are using consumer-grade GPS technology in cellphones to better analyze static-earth displacement and fault slips. The challenge, Given says, is filtering out signals that detect phone movement from those that detect ground movement.
Other agencies have applied GPS to geographic information systems, allowing workers to better visualize location-based data. For example, the National Park Service’s Submerged Resources Center has used GPS technology to research the nature and rate of deterioration of the USS Arizona in Pearl Harbor, Hawaii. The Interior Department’s Fish and Wildlife Service used GPS and mobile GIS technology to map its response to the 2010 British Petroleum oil spill in the Gulf of Mexico.
And that’s just scratching the surface.
“For example, the National Park Service currently measures visitor use at various parks by manually collecting voluntary surveys,” says John Steffenson, manager of federal civilian and global affairs at Esri, a developer of GIS software. “Sampling GPS location data from mobile devices would enable dramatically more accurate and detailed information about visitor use within parks.”