Subduction of oceanic asthenosphere: Evidence from sub-slab seismic anisotropy

摘要: [1] The oceanic asthenosphere is characterized as a low viscosity channel down to 200–300 km depth separating the cold lithosphere from above, and it intimately linked layer of seismic velocity prominent anisotropy observed globally beneath ocean basins. While subduction tectonic plates in convergent margins well recognized, fate remains enigmatic. We demonstrate that by weak azimuthal strong radial explains essence sub-slab shear-wave splitting patterns, where fast direction changes predominantly trench-parallel (or sub-parallel) under relatively steep zones frequently trench-normal shallow zones. To explain time, thickness subducted estimated be 100 ± 50 km.