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Tomographic Image of the Southern California Mantle

Humphreys, Eugene D. and Clayton, Robert W. (1990) Tomographic Image of the Southern California Mantle. Journal of Geophysical Research B, 95 (B12). pp. 19725-19746. ISSN 0148-0227.

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P wave teleseismic travel time delays recorded by the Southern California Array are inverted by the method of backprojection tomography to obtain images of variations in the P wave velocity structure to a depth of 750 km. Two major upper mantle features arc resolved: one beneath the Transverse Ranges region and another beneath the Salton Trough region. The Transverse Ranges feature appears as a curtainlike, east trending, high-velocity anomaly. This feature is ∼60 km thick, extends most deeply on its eastern end (to ∼250 km), and attains a maximum velocity −3% greater than average southern California mantle of the same depth. The Salton Trough feature, which is not as well resolved as the Transverse Ranges feature, is composed of low velocities in the upper 70–100 km. These P wave velocities arc depressed 3–4% compared to average southern California mantle. Tests of the inversion indicate the major aspects of the imaged structure are authentic.

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Additional Information:© 1990 American Geophysical Union. Received 10 November 1987; revised June 6, 1990; accepted 13 June 1990. We would like to thank Eric Ivans, Charlie Knox, Cliff Thurber, Ray Weldon, and anonymous reviewers for helpful comments on this paper. This research was supported by NSF grant EAR-8804953 and by NSF contract EAR-83-51371 and USGS contract 14-08-0001-01774. Contribution number 4932, Division of Geological and Planetary Sciences, California Institute of Technology.
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Caltech Division of Geological and Planetary Sciences4932
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Official Citation:Humphreys, E. D. and R. W. Clayton (1990), Tomographic image of the southern California mantle, J. Geophys. Res., 95(B12), 19,725–19,746, doi:10.1029/JB095iB12p19725.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34939
Deposited By: Ruth Sustaita
Deposited On:17 Oct 2012 15:04
Last Modified:11 Jun 2015 14:37

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