Scientists find an “earthquake gate” as California fault stress hits a 1

Researchers say stress on Southern California’s San Andreas and San Jacinto faults has reached some of the highest levels seen in a 1,000-year simulation. Because both faults are highly stressed at the same time, the Cajon Pass junction may be increasingly primed for a rupture that could cross both systems, although the study does not predict when an earthquake will happen. Scientists find an “earthquake gate” as California fault stress hits a 1,000-year high.

The white circle marks the location of the Cajon Pass and the three adjacent fault segments. The colors show the Coulomb stress, which indicates whether an earthquake is more or less likely to occur there. Earthquakes typically happen where sections of Earth’s crust move against one another, become stuck, and slowly accumulate stress.

When that stored energy is finally released, the result can be an earthquake. Two of the most important fault systems in Southern California are the San Andreas and San Jacinto faults. Together, they accommodate much of the tectonic motion in the region.