Abstract
We examine shear wave splitting in teleseismic phases to observe seismic anisotropy in the South American subduction zone. Data is from the CHARGE network, which traversed Chile and western Argentina across two transects between 30°S and 36°S. Beneath the southern and northwestern parts of the network, fast polarization direction (ϕ) is consistently trench‐parallel, while in the northeast ϕ is trench‐normal; the transition between these two zones is gradual. We infer that anisotropy sampled by teleseismic phases is localized within or below the subducting slab. We explain our observations with a model in which eastward, Nazca‐entrained asthenospheric flow is deflected by retrograde motion of the subducting Nazca plate. Resulting southward flow through this area produces N‐S ϕ observed in the south and northwest; E‐W ϕ result from interaction of this flow with the local slab geometry producing eastward mantle flow under the actively flattening part of the slab.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
