New evidence on the state of stress of the San Andreas fault system

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Abstract

Contemporary in situ tectonic stress indicators along the San Andreas fault system in central California show northeast-directed horizontal compression that is nearly perpendicular to the strike of the fault. Such compression explains recent uplift of the Coast Ranges and the numerous active reverse faults and folds that trend nearly parallel to the San Andreas and that are otherwise unexplainable in terms of strike-slip deformation. Fault-normal crustal compression in central California is proposed to result from the extremely low shear strength of the San Andreas and the slightly convergent relative motion between the Pacific and North American plates. Preliminary in situ stress data from the Cajon Pass scientific drill hole (located 3.6 kilometers northeast of the San Andreas in southern California near San Bernardino, California) are also consistent with a weak fault, as they show no right-lateral shear stress at ∼2-kilometer depth on planes parallel to the San Andreas fault.

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Publication type Article
Publication Subtype Journal Article
Title New evidence on the state of stress of the San Andreas fault system
Series title Science
DOI 10.1126/science.238.4830.1105
Volume 238
Issue 4830
Year Published 1987
Language English
Publisher Elsevier
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 7 p.
First page 1105
Last page 1111
Country United States
State California
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