Superweak asthenosphere in light of upper mantle seismic anisotropy
نویسندگان
چکیده
منابع مشابه
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...
متن کاملMantle dynamics and seismic anisotropy
a r t i c l e i n f o Keywords: seismic anisotropy mantle flow geodynamic modeling shear wave splitting surface wave analysis mantle convection Observations of seismic anisotropy yield some of the most direct constraints available on both past and present-day deformation in the Earth's mantle. Insight into the character of mantle flow can also be gained from the geodynamical modeling of mantle ...
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Asthenosphere is a venerable concept based on geological intuition of Reginald Daly nearly 100 years ago. There have been various explanations for the existence of the asthenosphere. The concept of a plume-fed asthenosphere has been around for a few years due to the ideas put forth by Yamamoto et al.. Using a two-dimensional Cartesian code based on finite-volume method, we have investigated the...
متن کاملAzimuthal 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...
متن کاملUpper mantle seismic anisotropy resulting from pressure-induced slip transition in olivine
Seismic anisotropy in the oceanic lithosphere results from flow-induced crystallographic preferred orientation of dry olivine during lithosphere creation. Recent experiments, however, showed that high water activity changes the flow mechanisms of olivine and hence the crystallographic preferred orientation, better explaining the seismic anisotropy in the mantle wedge above subduction zones. Whe...
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ژورنال
عنوان ژورنال: Geochemistry, Geophysics, Geosystems
سال: 2017
ISSN: 1525-2027,1525-2027
DOI: 10.1002/2017gc006886