Azimuthal Seismic Anisotropy of 70‐Ma Pacific‐Plate Upper Mantle

Origin of azimuthal seismic anisotropy in oceanic plates and mantle

Article history: Received 13 March 2014 Received in revised form 4 June 2014 Accepted 8 June 2014 Available online xxxx Editor: Y. Ricard

Azimuthal seismic anisotropy in the Earth’s upper mantle and the thickness of tectonic plates

S U M M A R Y Azimuthal seismic anisotropy, the dependence of seismicwave speeds on propagation azimuth, is largely due to fabrics within the Earth’s crust and mantle, produced by deformation. It thus provides constraints on the distribution and evolution of deformation within the upper mantle. Here, we present a new global, azimuthally anisotropic model of the crust, upper mantle and transitio...

Depth dependent azimuthal anisotropy in the western US upper mantle

Superweak asthenosphere in light of upper mantle seismic anisotropy

Earth’s upper mantle includes a 200 km thick asthenosphere underneath the plates where viscosity and seismic velocities are reduced compared to the background. This zone of weakness matters for plate dynamics and may be required for the generation of plate tectonics itself. However, recent seismological and electromagnetic studies indicate strong heterogeneity in thinner layers underneath the p...

Length scales, patterns and origin of azimuthal seismic anisotropy in the upper mantle as mapped by Rayleigh waves

Thorsten W. Becker,1 Göran Ekström,2 Lapo Boschi3 and John H. Woodhouse4 1Department of Earth Sciences, University of Southern California, 3651 Trousdale Parkway, Los Angeles CA 90089-0740, USA. E-mail: [email protected] 2Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory, Palisades, NY 10964, USA 3Eidgenössische Technische Hochschule, Zürich, Switzerland 4Department of ...