Many people worry about California’s San Andreas Fault and whether it might cause another big earthquake. Recent events in Myanmar, however, have shifted the way scientists think about earthquake predictions.
In March 2025, a massive Mw7.7 earthquake struck Mandalay, Myanmar. Researchers from the California Institute of Technology studied this quake using satellite images from before and after the event. Their goal? To better understand how future earthquakes may behave based on this data.
The Mandalay quake was devastating. It killed thousands, leaving countless others injured or missing. The shaking was felt in countries like China, India, Vietnam, and Thailand. What’s striking is that it happened along a long-dormant section of the Sagaing Fault that hadn’t moved in nearly 200 years. This quake marked the longest continental rupture ever observed, stretching 510 kilometers (about 317 miles).
What surprised researchers was that the quake did not follow the usual expectations. They predicted a major rupture would occur over a shorter, 300-kilometer (186-mile) stretch based on the seismic gap hypothesis. This theory suggests that if part of a fault remains still for too long, it might eventually slip to release the built-up stress.
This time, however, the fault released far more energy than expected. It indicates that the fault was not just releasing the strain, but also producing more than scientists had planned for.
When comparing this to the San Andreas Fault, there are remarkable similarities. Both faults are strike-slip types that run for hundreds of kilometers. Insights from the Myanmar earthquake suggest that scientists need to improve their models to better predict how the San Andreas may behave in the future.
Currently, most seismic hazard models focus on historical earthquake patterns. They often use a “time independent” approach, which doesn’t account for the current condition of the fault. For example, predictions might estimate the likelihood of an earthquake occurring in the next 30 years without considering whether specific sections of the fault have been locked for a long time.
This approach could miss the fact that the next major quake might not resemble past events. Jean-Philippe Avouac, a geology expert at Caltech, pointed out that the patterns of earthquakes are complex. He explained that just because a fault behaves a certain way in the past does not mean it will do so in the future. Each rupture can be unique, potentially releasing more energy than previously thought.
Historical data is often limited, making it hard for models to capture the full range of possible earthquakes. Avouac stressed that physics-based models could offer a more reliable alternative, allowing for adjustments based on actual observations.
For those who want to delve deeper, the study was published in the Proceedings of the National Academy of Sciences. Understanding these recent findings is crucial not just for scientists, but for anyone—or any community—living in earthquake-prone areas.
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