What might the next major earthquake on California’s San Andreas fault look like? Could it resemble the powerful 1857 quake, estimated at magnitudes 7.7 to 7.9? Or will it echo the infamous 1906 San Francisco earthquake, which started offshore and ruptured toward Humboldt and Santa Cruz counties?
Recent research suggests it won’t be identical to past events. A study in the journal Proceedings of the National Academy of Sciences examined an earthquake in Myanmar that ruptured a fault similar to the San Andreas. This earthquake, which occurred on March 28, ruptured more of the fault than scientists anticipated.
Dr. Solene L. Antoine, the study’s lead author from Caltech, emphasized that “earthquakes never come back exactly the same way.” This surprising finding highlights the unpredictable nature of faults.
The earthquake in Myanmar caused devastating effects. It resulted in 3,791 deaths in Myanmar and significant damage worth around $1.9 billion, affecting areas as far as Ho Chi Minh City in Vietnam. This was Myanmar’s strongest earthquake in nearly 80 years.
The magnitude 7.7 quake ruptured an astonishing 317 miles of the Sagaing fault, marking the longest documented rupture on a continent. Comparatively, the 1906 California earthquake affected 296 miles of the San Andreas, while the 1857 quake impacted 225 miles.
Experts like Jean-Philippe Avouac, a professor at Caltech, were surprised by the extent of the rupture. The findings challenge previous assumptions that only certain fault segments would become active after long periods of dormancy.
While this study sheds light on the behavior of faults, it does not predict when the next “Big One” will hit California. Scientists are developing models that simulate various earthquake scenarios over millennia. Although the San Andreas fault is complex, creating these models will help researchers understand possible future ruptures.
Avouac speculates that the San Andreas could behave differently, perhaps producing smaller quakes or a larger rupture extending from Monterey to San Bernardino or Riverside. In such a case, the earthquake could exceed magnitude 8, resulting in significant destruction across a vast area.
While predictions remain challenging, Antoine cautions, “There will be an earthquake at some point. If there is stress building up on the fault, it won’t hold forever.”
The research opens doors for more detailed forecasting of seismic activity, which will be crucial for preparing for future earthquakes. With tools like Sentinel satellites from the European Space Agency, scientists can gather vital data for improving these models.
Understanding these complexities helps us anticipate the unpredictable nature of seismic activity and better prepare for possible scenarios in the future.
