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New kinematic models for Pacific-North America motion from 3 ma to present, II: Evidence for a "Baja California shear zone"

Dixon, Timothy and Farina, Fred and DeMets, Charles and Suarez-Vidal, Francisco and Fletcher, John and Marquez-Azua, Bertha and Miller, Meghan and Sanchez, Osvaldo and Umhoefer, Paul (2000) New kinematic models for Pacific-North America motion from 3 ma to present, II: Evidence for a "Baja California shear zone". Geophysical Research Letters, 27 (23). pp. 3961-3964. ISSN 1944-8007


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Publisher’s or external URL: http://dx.doi.org/10.1029/2000GL008529


We use new models for present-day Pacific-North America motion to evaluate the tectonics of offshore regions west of the Californias. Vandenburg in coastal Alta California moves at the Pacific plate velocity within uncertainties (~1 mm/yr) after correcting for strain accumulation on the San Andreas and San Gregorio-Hosgri faults with a model that includes a viscoelastic lower crust. Modeled and measured velocities at coastal sites in Baja California south of the Agua Blanca fault, a region that most previous models consider Pacific plate, differ by 3-8 mm/yr, with coastal sites moving slower that the Pacific plate. We interpret these discrepancies in terms of strain accumulation on known on-shore faults, combined with right lateral slip at a rate of 3-4 mm/yr on additional faults offshore peninsular Baja California in the Pacific. Offshore seismicity, offset Quaternary features along the west coast of Baja California, and a discrepancy between the magnetically determined spreading rate in the Gulf Rise and the total plate rate from a geological model provide independent evidence for a "Baja California shear zone.".

Item Type: Article
Publisher’s Statement: ©2000. American Geophysical Union.
ID number or DOI: 10.1029/2000GL008529
Keywords: block; deformation; fault; gps; Mexico; plate; Southern California
Subjects: Q Science > QE Geology
NAU Depositing Author Academic Status: Faculty/Staff
Department/Unit: College of Engineering, Forestry, and Natural Science > School of Earth Sciences and Environmental Sustainability
Date Deposited: 12 Oct 2015 23:13
URI: http://openknowledge.nau.edu/id/eprint/730

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