Overview
- The U.S. Geological Survey reran the UCERF3 statewide forecast and released updated calculations Tuesday showing a 74.1% chance of a magnitude 6.7 or larger quake in the Bay Area over the next 30 years, up from about 72% in the prior outlook.
- The Hayward–Rodgers Creek system carries the single highest local risk at 34.3%, and scientists say a simultaneous rupture of those faults could produce a quake near magnitude 7.4.
- The San Andreas fault’s Bay Area probability rose to 25.5%, an increase of 3.6 percentage points, a change USGS scientists link to more elapsed time since past ruptures that allows tectonic stress to build.
- Researchers stress these figures are probabilistic not predictive, and USGS teams are developing models that include triggered events and aftershocks to better capture how quakes cascade and affect short‑term risk.
- Separate research and reporting highlight acute Southern California concerns — millennial‑scale stress on the San Andreas and San Jacinto, and the Cajon Pass junction’s potential to disrupt roads, power and supply chains if it fails.