California Scientists Pinpoint Where the Next Big Quake Could Hit

Just after midnight on Sunday, a modest 3.2‑magnitude tremor rattled the South Bay of Los Angeles. Residents woke up, some peered out the windows, but the quake left almost no damage. It was, in many ways, a reminder that the Earth never truly stops shifting beneath our feet.

On the same day, a group of geophysicists at the University of California, Riverside announced a breakthrough that could change how we think about seismic danger. While they can’t tell us when the next big shake will happen, they say they can now point to the exact patches of fault that are most likely to unleash it.

The core of their approach is surprisingly simple: measure how much strain has been quietly building up along a fault over years, and then let a computer algorithm highlight the sections that look “ready to snap.” Using a network of high‑precision GPS stations, the team tracks tiny ground motions—often just a few millimeters per year. Those data feed into a model that flags the “locked” bits of a fault where stress is accumulating, versus the parts that are already creeping harmlessly.

Gareth Funning and Axel Periollat, the lead researchers, explained to UC Riverside News that the method works best in subduction zones—those colossal regions where one tectonic plate slides beneath another. Subduction zones are notorious for producing the world’s most powerful quakes, the kind that register 8.5 on the magnitude scale or higher.

To prove the concept, they turned their eyes to the Pacific’s other side: Russia’s Kamchatka Peninsula. In July 2025 a strong earthquake there sparked tsunami warnings along the U.S. West Coast. The team’s algorithm correctly identified the precise segment of the subduction interface that ruptured, and even helped scientists realize the quake was smaller than the infamous 1952 event in the same area, based on the relative size of the resulting tsunami.

“We started with a relatively limited data set, just enough to get a rough picture of where strain was building,” Periollat said. “Seeing the model zero in on the actual rupture zone was a bit of a ‘wow’ moment—it told us we were on to something real.”

Now they’re applying the same toolbox to California’s own network of faults. The Hayward Fault in the Bay Area, for instance, has a curious mix of creeping sections and locked patches—much like a subduction zone in miniature. By mapping where the strain is concentrating, the researchers hope to identify the segments that could generate the next big shock in the region.

Of course, the scientists are quick to stress the limits of their work. The method does not predict the exact timing of an earthquake, nor does it forecast secondary hazards such as tsunamis or landslides. “Your peace of mind shouldn’t come from believing we can forecast the exact earthquake,” Funning warned. “Especially here in Southern California, it’s not a matter of if, but when. There is no substitute for preparation.”

Still, knowing the “where” is a powerful piece of the puzzle. Communities can focus retrofits, emergency drills, and public education on the most vulnerable zones. Planners can prioritize infrastructure upgrades where the stress is highest, potentially shaving years off the damage that a future quake would otherwise cause.

As the team refines their GPS‑based models and expands the sensor network, the hope is that a clearer map of Earth’s stress hotspots will emerge—one that gives cities, engineers, and families a little more time to get ready, even if the exact moment of the next shake remains stubbornly elusive.