California on Edge as Fault Stress Reaches Historic Highs

WHO:

Alternet - Liliane Burkhard, lead author, geophysicist and planetary geologist at the University of Bern in Switzerland.

Gizmodo - Researchers from the University of Bern.

WHAT:

Alternet - California's fault lines are under the most stress they have experienced in 1,000 years.

Gizmodo - The study published in the Journal of Geophysical Research, Solid Earth, indicates that stresses along the San Andreas and San Jacinto faults are the highest in the last millennium.

Gizmodo - The last major earthquake in the region was the Fort Tejon quake of 1857, which had a magnitude of 7.9.

Gizmodo - The San Jacinto-Bernadino section has reached a stress level of 3.6 megapascals (MPa), the highest in the 1,000-year simulation.

Gizmodo - The Mojave South section of the San Andreas fault has accumulated 2.8 MPa of stress.

WHERE:

Alternet - The fault line is located northeast of Los Angeles, California.

Gizmodo - Cajon Pass is the tectonically complex junction where the San Andreas and San Jacinto faults converge, near Los Angeles, San Bernardino, Riverside, and Coachella Valley.

WHEN:

Gizmodo - The study was published on June 3 in the Journal of Geophysical Research, Solid Earth.

Gizmodo - The simulation spans the years 1100 to 2025.

WHY:

Alternet - The accumulation of stress on fault lines can lead to earthquakes when the stress exceeds the friction holding the rocks together.

Gizmodo - The study emphasizes that the longer it has been since the last major earthquake, the more stress may have accumulated along the fault.

HOW:

Alternet - Researchers used geological data, including tree-ring anomalies and radiocarbon dating, to model the stress accumulation on faults.

Gizmodo - The physics-based earthquake cycle model simulates the process of stress accumulation in three spatial dimensions over time.

(UPDATED June 9, 2026 17:44 UTC)

Researchers from the University of Bern have found that California's fault lines are experiencing the highest stress levels in a millennium, particularly along the San Andreas and San Jacinto faults. In their study published in the Journal of Geophysical Research, Solid Earth, they report that the San Jacinto-Bernadino section has reached a stress level of 3.6 megapascals, while the Mojave South section of the San Andreas fault has accumulated 2.8 megapascals of stress. The study highlights that as time passes without a major earthquake, the potential for significant seismic activity increases, as stress accumulates until it exceeds the friction holding the rocks together.