Right-lateral fault motion along the slope-basin transition, Gulf of Santa Catalina, southern California

By: , and 
Edited by: Susan Cochran

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Abstract

An active fault system carrying a significant component of right-lateral strike-slip motion extends for ~60 km along the slope–basin transition, ~10 to 20 km offshore of the southern California coast from La Jolla to Dana Point. From south to north, this fault system includes the Carlsbad, San Onofre, and San Mateo fault zones. High-resolution single channel minisparker and chirp seismic reflection data gathered from 2006 to 2011 reveal complex and variable fault zones that are generally characterized by nearly vertical to steeply east-dipping faults with a reverse slip component. The Carlsbad fault zone shows evidence of reverse motion followed by normal separation and probably also includes a component of strike-slip offset. The San Onofre fault zone shows clear evidence of right-lateral slip, offsetting submarine gullies near the base of the slope by approximately 60 m. North of these offset gullies, the base of the slope bends about 30° to the west, following the trend of the San Mateo fault zone, but strands of the San Onofre fault zone trend obliquely up slope, appearing to merge with the Newport–Inglewood fault zone at the shelf edge. These San Onofre fault strands consist of several en echelon left-stepping segments separated by “pop-up” structures, which imply a significant component of right-lateral offset that may serve to transfer right-lateral slip from faults along the base of the slope to the Newport–Inglewood fault zone. Using approximate base Quaternary and base Holocene reflections, segments of the Carlsbad and San Onofre fault zones appear to have experienced right-lateral motion in the Holocene, whereas deformation along the San Mateo fault zone appears to represent a period of mostly pre-Quaternary transpression.

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Additional publication details

Publication type Book chapter
Publication Subtype Book Chapter
Title Right-lateral fault motion along the slope-basin transition, Gulf of Santa Catalina, southern California
Volume 110
Year Published 2019
Language English
Publisher Society for Sedimentary Geology
Contributing office(s) Pacific Coastal and Marine Science Center
Description 17 p.
Larger Work Type Book
Larger Work Subtype Monograph
Larger Work Title From the Mountains to the Abyss: The California Borderland as an Archive of Southern California Geologic Evolution
Country United States
State California
Other Geospatial Gulf of Santa Catalina