Southern California Faults at Highest Modeled Stress in 1,000 Years
A new physics-based 4D simulation identifies the Cajon Pass as a gate that could let ruptures link the San Andreas and San Jacinto faults, raising scenario risks to regional transport and energy infrastructure without predicting timing.
Overview
- A peer-reviewed study published this month used a physics-based, four-dimensional model to simulate 1,000 years of southern California seismic cycles and how stress transfers between fault segments.
- The model found peak stresses that are at or above the highest values in the 1,000-year run, with 3.6 megapascals on the San Jacinto (Bernardino) segment and 2.8 megapascals on the southern Mojave section of the San Andreas.
- Researchers introduce the concept of an “Earthquake Gate” at the Cajon Pass, where simulated stress conditions determine whether a rupture stops or jumps from one fault system to the other.
- Because both faults are modeled under high stress at the same time, the study raises the plausibility of a single, larger rupture that would threaten the Greater Los Angeles, San Bernardino, Riverside and Coachella Valley corridors and critical chokepoints such as I‑15, a major rail line and energy transmission lines.
- The authors stress the work is a refined risk scenario, not a timing forecast, and tie findings to historical behavior at the pass (1812 rupture that crossed it versus 1857 rupture that stopped) to underscore implications for preparedness and infrastructure planning.