Seismic anisotropy around subduction zones: Insights from three-dimensional modeling of upper mantle deformation and SKS splitting calculations

Short Note Seismic Anisotropy from SKS Splitting beneath Northeastern Tibet

The northeastern boundary of the Tibetan high plateau is marked by a 2 km topographic drop and a coincident rapid change in crustal thickness. Surface tectonics are dominated by the Kunlun strike-slip fault system and adjacent Kunlun concealed thrust. The main objective of the current study is to map lateral variations of seismic anisotropy parameters in this region along the linear INDEPTH IV ...

Upper mantle deformation beneath the North American–Pacific plate boundary in California from SKS splitting

[1] In order to constrain the vertical and lateral extent of deformation and the interactions between lithosphere and asthenosphere in a context of a transpressional plate boundary, we performed teleseismic shear wave splitting measurements for 65 permanent and temporary broadband stations in central California. We present evidence for the presence of two anisotropic domains: (1) one with clear...

Mid-mantle seismic anisotropy beneath southwestern Pacific subduction systems and implications for mid-mantle deformation

Observations of seismic anisotropy can offer relatively direct constraints on patterns of mantle deformation, but most studies have focused on the upper mantle. While much of the lower mantle is thought to be isotropic, several recent studies have found evidence for anisotropy in the transition zone and uppermost lower mantle (the mid-mantle), particularly in the vicinity of subducting slabs. H...

Mid-mantle anisotropy in subduction zones and deep water transport

The Earth’s transition zone has until recently been assumed to be seismically isotropic. Increasingly, however, evidence suggests that ordering of material over seismic wavelengths occurs there, but it is unclear what causes this. We use the method of source-side shear wave splitting to examine the anisotropy surrounding earthquakes deeper than 200 km in slabs around the globe. We find signific...

Upper mantle anisotropy beneath Peru from SKS splitting: Constraints on flat slab dynamics and interaction with the Nazca Ridge