GPS Data Could Predict Earthquakes Hours Ahead

2023 · VOA Learning English

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Transcript

1. Researchers say they have identified earth movement signals that could predict earthquakes up to two hours before they hit.

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2. The signals were recorded, or detected, by GPS collection devices. The devices were positioned in areas where major earthquakes had struck in the past.

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3. Scientists noted, however, that the right equipment does not currently exist to use the data to predict earthquakes.

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4. But if the sensitivity of current GPS measuring devices can be improved, the researchers say a new earthquake warning system could be possible.

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5. Earthquakes are caused by movements, or slips, in existing faults under Earth’s surface, the U.S. Geological Survey (USGS) explains

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6. A fault is a long break in rock attached to Earth’s crust. When tension builds up along a fault, energy waves are released and travel through the crust.

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7. This causes the ground to shake. Technology for predicting earthquakes currently remains very limited.

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8. But the USGS does have equipment that can pick up seismic data when an earthquake is just starting. The term seismic relates to earthquake activity.

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9. The USGS method makes it possible to warn people in areas where seismic activity is expected.

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10. But this method generally can only provide a warning several seconds before an earthquake hits. The USGS system is called ShakeAlert

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11. It has already been deployed along the U.S. West Coast.

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12. That is where the majority of earthquakes happen in the country.

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13. But the new detection method could produce warnings up to two hours before the damaging effects of an earthquake are felt.

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14. Such a system could save lives by giving people the chance to get out of buildings that might collapse in an earthquake.

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15. Two scientists from France’s National Research Institute for Sustainable Development carried out a study that described the latest results.

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16. The findings recently appeared in the publication Science

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17. For the study, researchers examined GPS data collected before and after past earthquake events around the world.

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18. The data was collected on 90 earthquakes measuring larger than 7 on the Richter scale. The study period covered the past 20 years.

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19. The team identified a pattern of fault movements as they examined the data collected from different areas.

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20. The movement signals were recorded within two hours of an earthquake striking.

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21. The researchers said the study demonstrates that faults generally begin to move about two hours before a large earthquake.

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22. Scientists had identified such signals before single earthquakes in the past.

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23. But until now, researchers were not able to link those signals to all seismic events.

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24. While the data identified this pattern, the scientists said the instruments that could capture GPS data in real time do not currently exist.

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25. The National Research Institute for Sustainable Development issued a statement on the development.

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26. It said that in order to make predictions, researchers “would need to measure signals at least 10 times smaller than what we can presently do.”

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27. Another way to possibly build a better earthquake prediction system would be to develop “dense measurement networks” that sit very close to faults.

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28. However, such an effort would require major technological progress, the institute said.

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29. Quentin Bletery is a geophysicist at Côte d’Azur University in the city of Nice.

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30. Bletery worked together on the study with Jean-Mathieu Nocquet, another researcher at the university.

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31. Bletery told Science that the study found that no observable movement was identified in the first 46 hours leading up to an earthquake.

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32. But starting around two hours before an earthquake, the GPS signals recording movement started to increase.

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33. To confirm its findings, the team compared that data to more than 100,000 random time periods recorded when no earthquakes were reported.

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34. “This tells us earthquakes are predictable in nature,” Bletery told Science

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35. The scientists note that more research is needed to support their findings.

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36. Much of the information used in the latest study, for example, depended heavily on data from GPS stations near major earthquake sites. I’m Bryan Lynn.

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