Sub-slab mantle anisotropy beneath south-central Chile

Upper and mid‐mantle anisotropy beneath the Tonga slab

[1] Measurements of source‐side splitting in S waves from events within the Tonga slab reveal anisotropy in the upper and mid‐mantle beneath the slab. We observed splitting for events originating at both upper mantle and transition zone depths. Anisotropic fast directions ( ) are trench parallel or sub‐parallel for both upper mantle and transition zone events. Delay times (dt) decrease with dep...

Sub-slab seismic anisotropy and mantle flow beneath the Caribbean and Scotia subduction zones Effects of slab morphology and kinematics

Subduction systems are vitally important to plate tectonics and mantle convection, but questions remain about many aspects of subduction dynamics, particularly the nature of sub-slab mantle flow. Observations of seismic anisotropy can shed light on the pattern of mantle flow in subduction systems, but major uncertainties remain regarding the interpretation of sub-slab anisotropy. Here, we prese...

Upper mantle anisotropy beneath the Geoscope stations

Seismic anisotropy has been widely studied this last decade, particularly by measuring splitting of vertically propagating core shear waves. The main interest in this technique is to characterize upper mantle flow beneath seismic stations. On the other hand, the major restriction in this method is that a single station gives a single anisotropy measurement. Alternative methods have been develop...

Modeling lower mantle anisotropy development in a subducting slab

A model is presented that simulates anisotropy development in a subducting slab from the upper–lower mantle boundary (661 km) to the core–mantle boundary (2891 km). Two phases are considered: orthorhombic MgSiO3-perovskite and cubic magnesiowuestite (Mg,Fe)O. Single crystal elastic properties at mantle conditions are obtained from existing density functional theory calculations and quasiharmoni...

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