Particle.news
Download on the App Store

Southern California Faults Reach 1,000‑Year Stress Peak

Researchers say the Cajon Pass can let a rupture jump between the San Andreas and San Jacinto faults, a scenario that reshapes hazard planning for the Los Angeles region.

Overview

  • A university release on June 10 highlighted a peer‑reviewed study led by Liliane Burkhard and published in the Journal of Geophysical Research that finds unusually high tectonic stress on Southern California faults.
  • The team fed a physics‑based computer model with a 1,000‑year earthquake history reconstructed from displaced sediments, radiocarbon dating and tree‑ring records to estimate present‑day stress.
  • Model results show stress on multiple segments of the San Andreas and San Jacinto systems at or above the highest levels seen in the past millennium, leaving the network in a “critically loaded” state after more than 160 years without a major southern rupture.
  • The study identifies Cajon Pass as an “earthquake gate” that can either block or allow a rupture to jump between the two faults, and it warns that a joint rupture would release far more energy and threaten Los Angeles, San Bernardino, Riverside and the Coachella Valley.
  • Authors and reporting outlets stress this is not a short‑term earthquake forecast but a scenario tool meant to guide seismic hazard assessments, infrastructure resilience work and emergency preparedness across the region.