A recent study published in the Proceedings of the National Academy of Sciences suggests that California’s next massive earthquake on the San Andreas fault will not be an exact replica of previous devastating quakes like 1857 or 1906. The research, led by scientists at Caltech, analyzed a massive earthquake that ruptured a longer section of a similar fault in Southeast Asia and found that earthquakes never come back exactly the same way.
The study’s lead author, Solene L. Antoine, said that the 2025 Mandalay earthquake in Myanmar ruptured an astonishing 317 miles of the Sagaing fault, which is the longest seismic rupture ever documented on a continent. This finding contradicts the expectation that California’s next “Big One” would share similar characteristics with previous devastating quakes.
Instead, researchers predict that future earthquakes could be smaller or larger than expected, with periods of increased activity followed by long periods of quiet. The San Andreas fault is more complex and has been locked for a long time, building up stress that will eventually lead to another massive earthquake.
According to the study’s co-author, Jean-Philippe Avouac, “it’s not going to come soon” because simulating earthquakes over many millennia on the San Andreas fault would require a heavy calculation. However, developing models of all possible scenarios could help scientists better understand the range of possible ruptures that could happen.
The researchers emphasize that while there will be an earthquake at some point, pinpointing its exact timing is impossible. Further research and observations are essential to refine models of future earthquakes, including from satellite data such as those provided by the European Space Agency’s Sentinel satellites.
Source: https://phys.org/news/2025-08-big-san-andreas-fault-earthquake.html