Joe Whearty, Thomas Rockwell, Gary Girty
Department of Geological Sciences, San Diego State University

Textural recognition of damage in sandstone adjacent to the San Jacinto Fault core

We present new evidence for the production of shallow damage in Quaternary sandstones along the San Jacinto fault (SJF), a right lateral strike-slip fault of the southern San Andreas fault system in southern California. The Bautista Formation, a moderately bedded plutonoclastic unit, bounds the southwest side of the SJF in Rockhouse Canyon, Anza Borrego State Park. We studied exposures located at 30-50 m and 100-110 m below the top of the Bautista alluvial fill. These depths are inferred to represent total burial depths for studied exposures. The age of the deposits is inferred to be middle Quaternary, and other exposures of the Bautista Formation along the Coyote Creek fault contain the Bishop Tuff, supporting this inference.

2013 SCEC Annual Meeting