University of Hawaii study says stress on San Andreas and San Jacinto faults at highest level in 1,000 years
Researchers using a physics-based model say stress on Southern California's San Andreas and San Jacinto fault systems has reached its highest point in a millennium, raising concerns for future seismic hazard assessments.
A University of Hawaii at Manoa team reports that stress accumulation along the San Andreas and San Jacinto faults in Southern California is at its highest level in the past 1,000 years. The researchers used a physics-based simulation that incorporated a millennium of regional earthquake history to estimate current stress levels.
The analysis suggests that the Cajon Pass could either block or permit a rupture that spans both fault systems, potentially linking them in a single earthquake event. Densely populated areas such as Los Angeles, San Bernardino, Riverside and the Coachella Valley could be affected if such a joint rupture occurs.
"The region may be capable of a large through-going rupture involving both fault systems," said scientist Liliane Burkhard. She added that more than 160 years have passed since the last major rupture on the system.
The study’s findings have implications for seismic hazard assessments in one of the nation’s most populated and infrastructure-critical regions.