Earth's Gravity: Not an Earthquake Predictor, New Study Finds
Scientists have developed a method to assess if minor changes in Earth's gravity can predict earthquakes. The research concluded that this approach is ineffective, refuting a prior hypothesis that suggested potential for improved warnings.
The precise prediction of earthquake location and timing remains challenging. Destructive earthquakes frequently occur in subduction zones, areas where tectonic plates interact. Subduction zones are considered key areas for identifying phenomena that might precede earthquakes.
Previous studies explored satellite data as a potential source for early warnings, suggesting the possibility of forecasting large earthquakes months in advance.
Satellite Data Under Scrutiny
Researchers analyzed measurements from NASA's GRACE and GRACE-FO satellites. Lei Wang, the study's author and an associate professor at The Ohio State University, stated that "precursors derived from single data points are largely invalid."
Wang explained that earthquake risk is influenced by numerous factors, and events often occur centuries apart. He noted that only a few decades of modern data are insufficient for accurate prediction. The study was presented at the American Geophysical Union's annual meeting.
Scientists have improved their understanding of earthquake triggers, but providing advance notice remains difficult. Current warning systems detect rapid seismic waves, alerting nearby populations seconds to minutes before shaking.
Unlike ground-based sensors, GRACE satellites monitor Earth's gravity changes and water mass redistribution. The team utilized this data to investigate whether significant subsurface gravity changes occurred before the 2010 Maule earthquake (8.8 magnitude) in Chile and the 2011 Tohoku megathrust earthquake (9.0 magnitude) in Japan.
Conclusion: No Superior Prediction Capabilities
Following a comprehensive analysis comparing various gravity data solutions with global GPS anomalies, the team concluded that satellites do not offer superior prediction capabilities for subsurface changes compared to conventional geodetic techniques.
Wang stated that detecting anomalous changes to Earth's gravity via satellite would significantly advance earthquake understanding and prediction, but confirmed a lack of solid evidence for this.
Global Applicability and Future Research
Dhamsith Weerasinghe, a co-author and PhD student at Ohio State, noted that even if satellite detection were possible, the method might not be globally applicable due to diverse earthquake mechanisms in different regions.
Weerasinghe explained that findings from one location could not be universally applied due to variations in geological geometry and materials, making widespread understanding and discovery too time-consuming.
The team intends to investigate gravity precursors for the recent 8.8 magnitude earthquake in Kamchatka, Russia. Wang hopes this research will guide future scientists in integrating historical data with new advancements in geodesy and environmental monitoring.
Wang concluded that current technology is not yet mature enough for predicting earthquakes days or hours in advance, highlighting the need for future contributions to the field.