EUGENE, Ore., Oct. 23 (UPI) -- U.S. geologists say they've determined southern California's San Jacinto fault zone is younger than thought and its slip rate probably faster than believed.
Researchers from three universities conducted a National Science Foundation-funded study of the earthquake-active region, concluding that sedimentation related to slip in the San Jacinto fault zone began about 1 million years ago -- significantly later than predicted by many models for faulting.
"Our findings suggest the San Jacinto fault absorbs a large share of the relative motion between the Pacific and North American plates," said principal investigator Rebecca Dorsey, a professor of geological sciences at the University of Oregon. "This is important both for understanding the development of this active plate boundary and for helping to constrain estimates of seismic hazards in southern California."
Until now the birth of the San Jacinto fault in the area of the Anza-Borrego Desert State Park had not determined.
The study, conducted by geologists from the University of Oregon, Western Washington University and Utah State University, appears in the November-December issue of the Geological Society of America Bulletin.
