Mechanical stress in the San Andreas and San Jacinto fault zones of Southern California has reached its highest levels in a millennium, significantly raising the likelihood of a major earthquake, infohub.kz reports.
An international team of scientists reconstructed 1,000 years of seismic activity in the region using a four-dimensional physical model. They found that the Cajon Pass, the critical junction of the two fault systems, acts as a kind of gateway. Depending on current pressure, this section can either halt an underground rupture or let it pass through, triggering a catastrophic shift in both systems simultaneously.
Currently, mechanical stress on the San Jacinto–Bernardino segment stands at 3.6 megapascals, while the adjacent San Andreas segment is at 2.8 megapascals. Researchers use the megapascal to measure pressure and mechanical stress in rocks. The synchronous record increase on both faults creates conditions similar to those that preceded major joint ruptures in the past, notably the 1812 earthquake.
If a rupture passes through Cajon Pass, strong shaking will affect densely populated areas, including Los Angeles, San Bernardino, and Riverside. Critical transportation and energy corridors would also be at risk. The authors stress that the model does not predict the exact date of a future disaster but only indicates the critical state of the geological system.