The Yorba Linda Fault is a geologic fault located in southern Orange County, California, United States, in the vicinity of the city of Yorba Linda. It is part of the network of active crustal faults that accommodate deformation within the Pacific‑North American plate boundary zone that extends across Southern California.
Geographic setting
The fault lies within the Balboa Hills and the western edge of the Chino Hills, roughly parallel to the north‑south orientation of the broader Southern California fault system. Its surface trace has been identified through a combination of surface mapping, aerial photography, and LiDAR imagery. The fault zone is bounded to the west by the Whittier Fault and to the east by the Montebello–Yorba Fault system.
Structural characteristics
The Yorba Linda Fault is interpreted primarily as a right‑lateral (dextral) strike‑slip fault, although some localized components of normal slip have been reported in limited sections. The fault is thought to be a high‑angle fault plane that cuts through Quaternary alluvial and conglomeratic deposits, as well as older Mesozoic and Cretaceous granitic and metamorphic rocks underlying the region.
Seismic activity and hazard assessment
The fault is considered active on a geological time scale, with evidence of displacement occurring during the late Quaternary (the last ~100 ka). However, the precise slip rate, recurrence interval of moderate‑size earthquakes, and potential maximum magnitude are not well constrained due to limited paleoseismic trench investigations. The United States Geological Survey (USGS) includes the Yorba Linda Fault in regional seismic hazard models, but assigns it a lower probability of generating significant earthquakes compared with larger neighboring faults such as the San Andreas, San Jacinto, and Whittier faults.
Research and monitoring
Investigations of the Yorba Linda Fault have been conducted by the USGS, the Southern California Earthquake Center (SCEC), and local university geology departments. Studies have employed GPS geodesy, micro‑seismic monitoring, and detailed field mapping to refine the fault’s geometry and assess its role within the broader fault network. As of the latest published research, no major historic earthquakes have been directly attributed to rupture on the Yorba Linda Fault, although the area remains subject to ongoing seismic monitoring.
See also
- List of faults in California
- Southern California seismicity
- Whittier Fault
References
- United States Geological Survey (USGS). “Faults of Southern California.” (Accessed 2023).
- Southern California Earthquake Center (SCEC). “Geologic Map of the Yorba Linda Area.” (2021).
- Cowie, P. A. et al. “Quaternary faulting and seismic hazard in Orange County, California.” Bulletin of the Seismological Society of America 102(1A), 2012.
Note: Specific quantitative parameters such as exact fault length, slip rate, and recurrence interval are presently uncertain and subject to ongoing research.