Brief
Study flags Cajon Pass as potential “earthquake gate” amid record stress levels
A new model shows tectonic stress at the Cajon Pass junction in Southern California has reached unprecedented levels, prompting warnings about a possible fault‑spanning quake.
By Felo News Desk · Published
Scientists have identified the Cajon Pass junction of the San Andreas and San Jacinto faults as an "earthquake gate" where stress levels have climbed to the highest values recorded in a 1,000‑year simulation, according to a study released on Oct. 3.
What happened
The research team built a four‑dimensional physics‑based model that tracks fault movement in three spatial dimensions while advancing through time. Using a millennium‑long record of past earthquakes—derived from radiocarbon dates, tree‑ring anomalies and historic accounts—the model reconstructed how stress accumulated and shifted across the southern San Andreas and San Jacinto systems.
What the reports add
The study, led by Dr. Liliane Burkhard of the University of Bern, incorporates contributions from the University of Hawaiʻi at Mānoa, the U.S. Geological Survey Earthquake Science Center in Pasadena and Scripps Institution of Oceanography at UC San Diego. It finds that in several locations around Cajon Pass, current tectonic stress not only matches but surpasses the peak values observed at any point in the simulated thousand‑year span. The authors describe the junction as a potential “gate” that could allow a rupture to jump from one fault to the other, influencing whether a large quake stays confined to a single fault or propagates across both.
What was said
"The model tracks how each earthquake changes stress on neighboring fault segments," the paper notes, highlighting the dynamic interaction between the two fault systems.
How it came about
The investigation follows decades of monitoring that have shown Southern California’s fault network to be among the most active in the United States. The region has not experienced a quake comparable to the 1857 magnitude‑7.9 Fort Tejon event, allowing stress to build over more than a century. By integrating diverse geological evidence into a long‑term simulation, the team aimed to clarify how future ruptures might evolve, especially at complex junctions like Cajon Pass.
Key facts
- Cajon Pass stress levels have exceeded any recorded in the model's 1,000‑year history. (sciencedaily.com)
- The study used a physics‑based four‑dimensional earthquake cycle model. (sciencedaily.com)
- Researchers incorporated data from radiocarbon dating, tree rings and historic records. (sciencedaily.com)
Sources
- [1] sciencedaily.com — originally reported as “Scientists find an “earthquake gate” as California fault stress hits a 1,000-year high”
