Overview
- USGS scientists reran the third Uniform California Earthquake Rupture Forecast with a 2026 start date and published a recalculation that sets the Bay Area’s 30‑year chance of a magnitude 6.7 or larger quake at 74.1%.
- The Hayward–Rodgers Creek fault system carries the highest Bay Area risk at 34.3%, and the San Andreas probability rose to 25.5%, reflecting increased conditional likelihood after a decade with no major ruptures.
- Researchers say the higher numbers come from added elapsed time on fault sections that raises tectonic stress, and they are developing models that will add aftershocks and triggered events to improve shorter‑term forecasts.
- Experts warn the modest percentage increases still matter for dense communities and critical infrastructure, and they urge stronger building standards and resilient design for hospitals, bridges, power lines and roads.
- UCERF3 is a statistical statewide forecast that estimates where and how often ruptures can occur, so the new figures describe regional decades‑long risk rather than precise timing and should guide preparedness and planning.