GPS could predict earthquakes two hours ahead, but there’s a catch
An analysis of GPS data has revealed a slow and otherwise undetectable slip of tectonic plates that begins two hours before an earthquake – but detecting this in advance would require more accurate sensors
By Matthew Sparkes
20 July 2023
Collapsed buildings in Antakya, Turkey, on 20 February, following a 7.8-magnitude earthquake
YASIN AKGUL/AFP/Getty Images
Earthquakes could theoretically be predicted 2 hours before they occur, saving countless lives – but we must first develop GPS sensors that are 100 times more precise than those in use today.
Over the past few decades, expert opinion has shifted on whether any telltale seismic activity exists prior to earthquakes, or if they are inherently chaotic and unpredictable events. Now, Quentin Bletery and Jean-Mathieu Nocquet at Côte d’Azur University in Nice, France, may have settled the debate.
The pair have used GPS data to identify a gradual, accelerating slip between tectonic plates in the lead-up to an earthquake. These slips are too small to appear on seismographs, but could – if detected – indicate when earthquakes are about to begin. Such an approach has been tried before, but Bletery says previous research has only looked at a handful of earthquakes and produced warning signs that are also seen when no earthquake follows, or that are observed an uncertain amount of time before the quake.
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The researchers used GPS measurements gathered over a period of 5 minutes, making them accurate to within 1 centimetre, taken during the 48 hours prior to 90 separate earthquakes. With a combined data set of over 3000 measurements, they compared recorded ground movements with the expected direction of movement that each site would see during an earthquake.
In each case, they found that the largest movement in the expected direction occurred just prior to the earthquake. They also found that the last 23 data points showed a gradually increasing movement in the expected direction, and the final seven were higher than any others during the entire 48-hour period.
