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Mantle Heterogeneities and the SCEC Reference Three-Dimensional Seismic Velocity Model Version 3

Kohler, M. D. and Magistrale, H. and Clayton, R. W. (2003) Mantle Heterogeneities and the SCEC Reference Three-Dimensional Seismic Velocity Model Version 3. Bulletin of the Seismological Society of America, 93 (2). pp. 757-774. ISSN 0037-1106. http://resolver.caltech.edu/CaltechAUTHORS:20121001-141154836

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Abstract

We determine upper mantle seismic velocity heterogeneities below Southern California from the inversion of teleseismic travel-time residuals. Teleseismic P-wave arrival times are obtained from three temporary passive experiments and Southern California Seismic Network (SCSN) stations, producing good raypath coverage. The inversion is performed using a damped least-squares conjugate gradient method (LSQR). The inversion model element spacing is 20 km. Before the inversion, the effects of crustal velocity heterogeneities represented by the Southern California Earthquake Center (SCEC) seismic velocity model version 2 are removed from the teleseismic travel times. The P-wave inversion produces a variance reduction of 43%. S-wave velocities are determined from laboratory Vp/Vs ratios. The most prominent features imaged in the results are high P-wave velocities (+3%) in the uppermost mantle beneath the northern Los Angeles basin, and the previously reported tabular high-velocity anomaly (+3%) to depths of 200 km beneath the Transverse Ranges, crosscutting the San Andreas fault. We incorporate the upper mantle seismic velocity heterogeneities into the SCEC Southern California reference seismic velocity model. The prior accounting for the crustal velocity heterogeneity demonstrates the utility of the top-down method of the SCEC seismic velocity model development.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1785/0120020017 DOIArticle
http://bssa.geoscienceworld.org/content/93/2/757PublisherArticle
Additional Information:© 2003 by the Seismological Society of America. Manuscript received 12 January 2002. The LARSE and LABPSE experiments were made possible by the loan of SCEC Portable Broadband Instrument Center and IRIS PASSCAL seismometers, and the support of their staffs. We thank Ken Dueker for providing the large compilation of Southern California Seismic Network P-wave travel-time residual data. This research was supported by the Southern California Earthquake Center. SCEC is funded by NSF Cooperative Agreement EAR-8920136 and USGS Cooperative Agreements 14-08-0001- A0899 and 1434-HQ-97AG01718. The SCEC Contribution Number for this article is 630.
Funders:
Funding AgencyGrant Number
Southern California Earthquake Center (SCEC)UNSPECIFIED
NSF Cooperative AgreementEAR-8920136
USGS Cooperative Agreement14-08-0001-A0899
USGS Cooperative Agreement1434-HQ-97AG01718
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Southern California Earthquake Center (SCEC)630
Record Number:CaltechAUTHORS:20121001-141154836
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20121001-141154836
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34599
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:01 Oct 2012 21:35
Last Modified:13 Aug 2014 21:03

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