California's Most Dangerous Fault Line Hits Highest Stress Level in 1,000 Years

A critical junction where two of California's most powerful fault systems meet has been quietly accumulating stress levels matching 1,000-year highs, according to a new study.

It's been over 100 years since the San Andreas and San Jacinto faults produced a major earthquake, and in peacetime, tectonic stress has grown to significant heights along key parts of the systems, raising concern of a dangerous earthquake that could be catastrophic for one of the most densely populated areas in the U.S.

The area of concern is Cajon Pass, a critical fault junction northeast of Los Angeles, where the Mojave South and North San Bernardino segments of the San Andreas Fault and the San Jacinto Bernardino segment of the San Jacinto Fault meet.

Researchers used computer simulations of the last 1,000 years of rupture history to estimate stress levels on these critical fault segments and impacts surrounding areas over time. The study found stress levels of 2.8 on the Mojave South segment, 1.8 on the North San Bernardino segment, and 3.6 on the San Jacinto Bernardino segment.

The study highlights the "earthquake gate" that plays a pivotal role in determining whether a future earthquake stays confined to a single fault or cascades across multiple connected fault systems, increasing the potential size and reach of the event.

Suddenly, we are faced with the reality that stress continues to build across one of the most complex and consequential fault junctions in North America. It's time to prepare for the inevitable earthquake that will shake the foundations of the world.