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dc.creatorWang, Xinling L.en_US
dc.creatorNi, James F.en_US
dc.creatorAster, Richarden_US
dc.creatorSandvol, Ericen_US
dc.creatorWilson, Daviden_US
dc.creatorSine, Christopheren_US
dc.creatorGrand, Stephen P.en_US
dc.creatorBaldridge, W. Scotten_US
dc.date.accessioned2016-10-28T19:52:00Z
dc.date.available2016-10-28T19:52:00Z
dc.date.issued2008-10en_US
dc.identifierdoi:10.15781/T2MK65B67
dc.identifier.citationWang, Xinling, James F. Ni, Richard Aster, Eric Sandvol, David Wilson, Christopher Sine, Stephen P. Grand, and W. Scott Baldridge. "Shear-wave splitting and mantle flow beneath the Colorado Plateau and its boundary with the Great Basin." Bulletin of the Seismological Society of America, Vol. 98, No. 5 (Oct., 2008): 2526-2532.en_US
dc.identifier.issn0037-1106en_US
dc.identifier.urihttp://hdl.handle.net/2152/43272
dc.description.abstractShear-wave splitting measurements from SKS and SKKS phases show fast polarization azimuths that are subparallel to North American absolute plate motion within the central Rio Grande Rift (RGR) and Colorado Plateau (CP) through to the western rim of the CP, with anisotropy beneath the CP and central RGR showing a remarkably consistent pattern with a mean fast azimuth of 4 degrees +/- degrees 6 E of N. Approaching the rim from the southeast, fast anisotropic directions become north-northeast-south-southwest (NNE-SSW), rotate counter clockwise to north-south in the CP-GB transition, and then to NNW-SSE in the western Great Basin ( GB). This change is coincident with uppermost mantle S-wave velocity perturbations that vary from +4% beneath the western CP and the eastern edge of the Marysvale volcanic field to about -8% beneath the GB. Corresponding delay times average 1.5 sec beneath the central CP, decrease to approximately 0.8 sec near the CP-GB transition, and increase to about 1.2 sec beneath the GB. For the central CP, we suggest anisotropy predominantly controlled by North American plate motion above the asthenosphere. The observed pattern of westward-rotating anisotropy from the western CP through the CP-GB transition may be influenced to asthenospheric flow around a CP lithospheric keel and/or by vertical flow arising from edge-driven small-scale convection. The anisotropic transition from the CP to the GB thus marks a first-order change from absolute plate motion dominated lithosphere-asthenosphere shear to a new regime controlled by regional flow processes. The NNW-SSE anisotropic fast directions of split SKS waves in the eastern GB area are part of a broad circular pattern of seismic anisotropic fast direction in the central GB that has recently been hypothesized to be due to toroidal flow around the sinking Juan de Fuca-Gorda slab.en_US
dc.description.sponsorshipNational Science Foundation EAR 9706094, 9707188, 9707190, 0207812en_US
dc.description.sponsorshipLos Alamos National Laboratory Institute of Geophysics and Planetary Physicsen_US
dc.description.sponsorshipNational Science Foundation Cooperative EAR-000430en_US
dc.description.sponsorshipDepartment of Energy National Nuclear Security Administrationen_US
dc.language.isoEnglishen_US
dc.relation.ispartofen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjectwestern united-statesen_US
dc.subjectseismic anisotropyen_US
dc.subjectnorth-americaen_US
dc.subjectcentral utahen_US
dc.subjectdeformationen_US
dc.subjectmodelen_US
dc.subjectlithosphereen_US
dc.subjectconstraintsen_US
dc.subjecttectonicsen_US
dc.subjectpatternsen_US
dc.subjectgeochemistry & geophysicsen_US
dc.titleShear-Wave Splitting and Mantle Flow Beneath the Colorado Plateau and its Boundary with the Great Basinen_US
dc.typeArticleen_US
dc.description.departmentGeological Sciencesen_US
dc.rights.restrictionOpenen_US
dc.identifier.doi10.1785/0120080107en_US
dc.contributor.utaustinauthorWilson, Daviden_US
dc.contributor.utaustinauthorSine, Christopheren_US
dc.contributor.utaustinauthorGrand, Stephen P.en_US
dc.relation.ispartofserialBulletin of the Seismological Society of Americaen_US


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