India, June 29 -- A new study has raised fresh concerns about earthquake risk in Southern California. Researchers say the region's two major fault systems, the San Andreas Fault and the San Jacinto Fault are carrying more built-up stress than at any time in the last 1,000 years. The findings do not predict when an earthquake will happen, but they suggest conditions are now similar to those seen before some of the area's largest historic quakes. The study was published in the Journal of Geophysical Research: Solid Earth and was led by Dr. Liliane Burkhard of the University of Bern in Switzerland.

Earthquakes happen when stress slowly builds along faults and is suddenly released. To understand how much stress is currently stored beneath So...