Quaternary-active faults and the role of inherited structures in the Sacramento-San Joaquin Delta, western Central Valley, northern California

Tektonika
By: , and 

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Abstract

Seismic sources and their associated hazards within the Sacramento-San Joaquin Delta region of north-central California are relatively poorly characterized as compared to other, more heavily studied regions of northern California, such as the San Francisco Bay Area. Here we present a synthesis of subsurface, bedrock geology, and geodetic datasets from the Delta and from the Coast Ranges and Diablo Range to the northwest and southwest, respectively. We integrate these data and our own surface geologic and geomorphic observations to present a comprehensive review of faults in the Delta that exhibit Quaternary activity. Structural geologic data from the surrounding region highlight the significant influence that Late Cretaceous-to-Paleogene forearc structures exert on the geometry and kinematics of major Quaternary-active structures within the Delta. These inherited structures — including the Pittsburg-Kirby Hills Fault, Midland Fault, and Great Valley Fault System — exhibit a range of geometries and kinematics. Analysis of geomorphology along these structures suggests that these structures combine to accommodate Quaternary strain across the Delta region. A clearer understanding of subsurface geometries and structural relationships, built upon the regional tectonic history, provides insight into modern deformation accommodated on older structures and helps inform interpretations of seismic hazard within the Delta.

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Publication type Article
Publication Subtype Journal Article
Title Quaternary-active faults and the role of inherited structures in the Sacramento-San Joaquin Delta, western Central Valley, northern California
Series title Tektonika
DOI 10.55575/tektonika2024.2.1.46
Edition 40
Volume 2
Issue 1
Year Published 2025
Language English
Publisher University of Aberdeen
Contributing office(s) Earthquake Science Center
Description 28 p.
First page 67
Country United States
State California
Other Geospatial Sacramento-San Joaquin Delta, western Central Valley
Additional publication details