California quake study reframes risk

A Caltech study of Myanmar's March quake on a similar fault path suggests California's San Andreas could rupture differently than past quakes.

California's next big quake may unfold in unexpected ways

Researchers at Caltech analyzed satellite data from the March 28 Myanmar quake on the Sagaing fault, finding the rupture stretched about 317 miles, the longest continental rupture on record and longer than scientists predicted.

The study argues that earthquakes do not repeat in the same pattern. It suggests a future San Andreas quake could take many forms, from smaller, separate ruptures to a single event that spans multiple counties. While simulations can map possible scenarios, they cannot predict the exact timing of the next large quake.

The research challenges the idea that one worst case can be repeated exactly. It shows that fault behavior is complex and influenced by ongoing stress redistribution after each quake. For California, this means hazard planning must account for a range of outcomes rather than a single scenario.

In practical terms, preparedness hinges on resilient infrastructure, adaptable emergency plans, and clear risk communication that reflects scientific uncertainty. Satellite data and long-term modeling offer a path to better planning, even as they remind us that the next Big One remains inherently unpredictable.

Highlights

Ongoing satellite monitoring and longer simulations will shape how communities prepare for the next seismic test.