Geomorphic evidence for active faulting along the southern margin of the central Transverse Ranges, Southern California

TitleGeomorphic evidence for active faulting along the southern margin of the central Transverse Ranges, Southern California
Publication TypeJournal Article
Year of Publication1993
AuthorsRubin C M, Sieh KE
JournalBulletin of the Association of Engineering Geologists
Volume30
Issue4
Pagination521-523
Accession NumberOSTI ID: 142161
Abstract

The role of compressional tectonics in the Los Angeles basin and central Transverse Ranges is poorly understood, yet earthquake potential along both the frontal fault system and along blind thrust faults located beneath the basin is considered high. Conventional wisdom contends that the Sierra Madre segment of the frontal fault system, located west of the San Antonio fault, has a significantly lower slip rate than segments of the frontal fault system to the east. (Cucamonga fault) or to the west (San Fernando segment). A critical element of Weldon and Humphreys` (1986) kinematic model for southern California is the lack of observed large-scale Quaternary convergence in the central Transverse Ranges. Documentation of active structures in the central Transverse Ranges will help address the earthquake potential in the San Gabriel Valley and begin to answer critical questions on how can the central segment be inactive, while adjacent segments are considered active? The authors initial geologic studies along the front of the central Transverse Ranges suggest that the Sierra Madre segment is an active tectonic feature and represents a significant seismic hazard along the mountain front. Paleoseismic data are sparse for the frontal fault system and the Sierra Madre segment is not designated as active under the Alquist-Priolo Special Studies Zone Act.