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Fault zone structure from topography: signatures of en echelon fault slip at Mustang Ridge on the San Andreas Fault, Monterey County, California

Tectonics

By:
, , ,
DOI: 10.1029/2010TC002673

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Abstract

We used high-resolution topography to quantify the spatial distribution of scarps, linear valleys, topographic sinks, and oversteepened stream channels formed along an extensional step over on the San Andreas Fault (SAF) at Mustang Ridge, California. This location provides detail of both creeping fault landform development and complex fault zone kinematics. Here, the SAF creeps 10–14 mm/yr slower than at locations ∼20 km along the fault in either direction. This spatial change in creep rate is coincident with a series of en echelon oblique-normal faults that strike obliquely to the SAF and may accommodate the missing deformation. This study presents a suite of analyses that are helpful for proper mapping of faults in locations where high-resolution topographic data are available. Furthermore, our analyses indicate that two large subsidiary faults near the center of the step over zone appear to carry significant distributed deformation based on their large apparent vertical offsets, the presence of associated sag ponds and fluvial knickpoints, and the observation that they are rotating a segment of the main SAF. Several subsidiary faults in the southeastern portion of Mustang Ridge are likely less active; they have few associated sag ponds and have older scarp morphologic ages and subdued channel knickpoints. Several faults in the northwestern part of Mustang Ridge, though relatively small, are likely also actively accommodating active fault slip based on their young morphologic ages and the presence of associated sag ponds.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Fault zone structure from topography: signatures of en echelon fault slip at Mustang Ridge on the San Andreas Fault, Monterey County, California
Series title:
Tectonics
DOI:
10.1029/2010TC002673
Volume
29
Year Published:
2010
Language:
English
Publisher:
American Geophysical Union (AGU)
Publisher location:
Washington, D.C.
Contributing office(s):
Earthquake Science Center
Description:
TC5003: 16 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Country:
United States
State:
California