The Deformational Journey of the Nazca Slab From Seismic Anisotropy

Shubham Agrawal, Caroline M. Eakin, Daniel E. Portner, Emily E. Rodriguez, Susan L. Beck

Research output: Contribution to journalArticle

Abstract

The Andean subduction zone is an excellent place to study deformation within a subducting slab as a function of depth, owing to the varying and well-resolved geometry of the subducting Nazca slab beneath South America. Here we combine the results of source-side shear wave splitting with the latest regional tomography model to isolate intraslab raypaths and determine the spatial distribution of anisotropy within the Nazca slab. We observe that in the upper mantle, the intraslab anisotropy appears strongest where the slab is most contorted, suggesting a strong link between anisotropy and subduction-related slab deformation. We identify a second source of anisotropy (δt∼ 1 s) within the subducting slab at lower mantle depths (660–800 km). The surrounding mantle and transition zone appear largely isotropic, with deep anisotropy concentrated within the slab as it deforms while entering the higher-viscosity lower mantle.

Original languageEnglish (US)
Article numbere2020GL087398
JournalGeophysical Research Letters
Volume47
Issue number11
DOIs
StatePublished - Jun 16 2020

Keywords

  • Nazca slab
  • seismic anisotropy
  • slab anisotropy
  • slab deformation
  • source side splitting

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

Fingerprint Dive into the research topics of 'The Deformational Journey of the Nazca Slab From Seismic Anisotropy'. Together they form a unique fingerprint.

  • Cite this