GEOMETRY, KINEMATICS, AND SLIP HISTORY OF THE ELSINORE FAULT IN THE NORTHERN SANTA ANA MOUNTAINS, SOUTHERN CALIFORNIA

Author

Gideon Schyler O. El-Rahi, California State University - San BernardinoFollow

Date of Award

5-2025

Document Type

Restricted Thesis: Campus only access

Degree Name

Master of Science in Geology

Department

Geological Sciences

First Reader/Committee Chair

Bidgoli, Tandis

Abstract

The Glen Ivy fault segment of the Elsinore fault zone bifurcates into the Whittier fault and Chino fault in Corona, California. Geologic slip rates for the Elsinore fault zone range from 1-9 mm/yr, with limited slip rate studies on this portion of the fault. Access to new airborne LiDAR (Light Detection and Ranging) datasets and improvements in Quaternary dating methods have motivated a re-examination of the previously mapped fault, with objectives to: (1) differentiate the geologic units, (2) establish the geometry and kinematics of the faults, and (3) establish slip magnitudes and rates. The high-resolution (1.0 m²) LiDAR topographic data are paired with NAIP (National Agriculture Imagery Program) data and historical aerial photography to produce a detailed (1:10,000-scale) geologic map of the Glen Ivy fault segment of the Elsinore fault zone in Corona, California, focusing on portions of the Corona South, Corona North, Black Star Canyon, and Prado Dam 7.5-minute quadrangles. Furthermore, the use of LiDAR allows for detailed surface analysis to improve surface visualization and derive topographic information through terrain ruggedness index and topographic surface roughness analysis. Mapping shows that the southern portion of the Glen Ivy fault segment is primarily a single stranded fault. As the fault progresses northward, it becomes a complex, multi-stranded fault zone with some dip-slip component. While the Whittier fault segment is thought to be the primary extension of the Elsinore fault zone, mapping shows that paleochannels of the Santa Ana River have been displaced along the fault, with the farthest channel offset approximately ~13 km. The magnitude­ of the displacement is consistent with o­ffsets recorded by a range of markers in the bedrock, suggesting the total lateral slip for this portion of the fault is 13-15 km. The results also suggest that the Chino fault segment is the primary extension of the Elsinore fault. On-going efforts focus on obtaining new geochronological constraints for Pliocene to Quaternary deposits in the foothills of the Santa Ana Mountains for slip rate analysis.

Recommended Citation

El-Rahi, Gideon Schyler O., "GEOMETRY, KINEMATICS, AND SLIP HISTORY OF THE ELSINORE FAULT IN THE NORTHERN SANTA ANA MOUNTAINS, SOUTHERN CALIFORNIA" (2025). Electronic Theses, Projects, and Dissertations. 2226.
https://scholarworks.lib.csusb.edu/etd/2226