New Evidence on the State of Stress of the San Andreas Fault System
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.
Additional Information
© 1987 American Association for the Advancement of Science. Received 27 July 1987; accepted 5 October 1987. We thank A. Lachenbruch, J. Savage, R. Weldon, A. McGarr, and an anonymous reviewer for comments on earlier versions of this manuscript and for suggesting important improvements.Additional details
- Eprint ID
- 98684
- DOI
- 10.1126/science.238.4830.1105
- Resolver ID
- CaltechAUTHORS:20190917-135250189
- Created
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2019-09-17Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field