Cajon Pass earthquake risk identified in Southern California

Scientists are warning of a significant earthquake risk in Cajon Pass, a critical transportation corridor in Southern California. Located between the San Bernardino and San Gabriel mountains, the area sits at the intersection of the San Andreas and San Jacinto fault systems. Researchers describe the location as an “earthquake gateway,” where a rupture could jump between or penetrate both fault systems.

Liliane Burkhard, a geophysicist at the University of Bern and lead author of the study, stated that current conditions suggest a major earthquake could occur within the current generation. While the exact timing is unknown, researchers estimate a potential magnitude of 7.5 at the intersection. Ken Hudnut, a former expert at the U.S. Geological Survey (USGS), noted that the San Andreas fault is accumulating energy, a risk that has been highlighted for years.

The Cajon Pass is particularly vulnerable due to its dense concentration of essential infrastructure, including railways, highways, power lines, fiber optic cables, and water and gas pipelines. Approximately 160,000 vehicles pass through the area daily. A major seismic event could cause widespread disruptions to supply chains, communications, and energy systems. Previous models suggest a magnitude 7.8 earthquake on the San Andreas fault could result in over 1,800 deaths and $200 billion in damages.