Millennium-High Stress on California Faults Triggers Big-Quake Alarm

A 1,000-year modeling study of Southern California’s San Andreas and San Jacinto faults shows current tectonic stresses at or near the highest levels in the past millennium, heightening quake hazard. The Cajon Pass junction may act as an “earthquake gate” that could allow large ruptures to cross both faults, potentially increasing damage if such an event occurs. The research does not predict when a quake could happen, but it provides a physics-based hazard framework to improve preparedness for California and other complex fault systems.