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

Timothy Dixon, Fred Farina, Charles DeMets, Francisco Suarez-Vidal, John Fletcher, Bertha Marquez-Azua, Meghan Miller, Osvaldo Sanchez, Paul J Umhoefer

Research output: Contribution to journalArticle

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Abstract

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".

Original languageEnglish (US)
Pages (from-to)3961-3964
Number of pages4
JournalGeophysical Research Letters
Volume27
Issue number23
DOIs
StatePublished - 2000

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Lower California (Mexico)
shear zone
Pacific plate
kinematics
shear
gulfs
coasts
lower crust
seismicity
tectonics
crusts
slip
North America
coast
rate

ASJC Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)

Cite this

New kinematic models for Pacific-North America motion from 3 MA to present, II : Evidence for a "Baja California shear zone". / Dixon, Timothy; Farina, Fred; DeMets, Charles; Suarez-Vidal, Francisco; Fletcher, John; Marquez-Azua, Bertha; Miller, Meghan; Sanchez, Osvaldo; Umhoefer, Paul J.

In: Geophysical Research Letters, Vol. 27, No. 23, 2000, p. 3961-3964.

Research output: Contribution to journalArticle

Dixon, T, Farina, F, DeMets, C, Suarez-Vidal, F, Fletcher, J, Marquez-Azua, B, Miller, M, Sanchez, O & Umhoefer, PJ 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, vol. 27, no. 23, pp. 3961-3964. https://doi.org/10.1029/2000GL008529
Dixon, Timothy ; Farina, Fred ; DeMets, Charles ; Suarez-Vidal, Francisco ; Fletcher, John ; Marquez-Azua, Bertha ; Miller, Meghan ; Sanchez, Osvaldo ; Umhoefer, Paul J. / New kinematic models for Pacific-North America motion from 3 MA to present, II : Evidence for a "Baja California shear zone". In: Geophysical Research Letters. 2000 ; Vol. 27, No. 23. pp. 3961-3964.
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