So GPS might tell scientists the speed at which the opposite sides of the San Andreas Fault are creeping past each other, while seismometers measure the ground shaking when that California fault ruptures in a quake.

GPS receivers served a different purpose-to track geologic processes that happen on much slower scales, such as the rate at which Earth’s great crustal plates grind past one another in the process known as plate tectonics. Feel an earthquakeįor centuries geoscientists have relied on seismometers, which measure how much the ground is shaking, to assess how big and how bad an earthquake is. Here are some surprising things scientists have only recently realized they could do with GPS.Ĭredit: Knowable Magazine Source UNAVCO 1. “Well, it turned out we were able to do it.” “People thought I was crazy when I started talking about these applications,” says Kristine Larson, a geophysicist at the University of Colorado Boulder who has led many of the discoveries and wrote about them in the 2019 Annual Review of Earth and Planetary Sciences.

And researchers have even MacGyvered some GPS receivers into acting as snow sensors, tide gauges and other unexpected tools for measuring Earth. GPS has led to better warning systems for natural disasters such as flash floods and volcanic eruptions. Over the last decade, faster and more accurate GPS devices have allowed scientists to illuminate how the ground moves during big earthquakes. Using that fine-grained information, along with new ways to analyze the signals, researchers are discovering that GPS can tell them far more about the planet than they originally thought it could. With fancier (and more expensive) GPS receivers, scientists can pinpoint their locations down to centimeters or even millimeters. A basic GPS receiver, like the one in your smartphone, determines where you are-to within about 1 to 10 meters-by measuring the arrival time of signals from four or more satellites. GPS consists of a constellation of satellites that send signals to Earth’s surface. But you’d probably still be surprised at all the things that GPS-the global positioning system that underlies all of modern navigation-can do. You might even hike with a GPS device to find your way through the backcountry. You might think you’re an expert at navigating through city traffic, smartphone at your side.

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