@article{cee90dcdfb1749b69a28ab2571df9405,
title = "Variable seismic anisotropy across the Peruvian flat-slab subduction zone with implications for upper plate deformation",
abstract = "We performed shear wave splitting analyses to investigate seismic anisotropy across the northern extent of the Peruvian flat-slab subduction region. We used core-mantle refracted SKS, SKKS and PKS phases from teleseismic events (88° > Δ < 150°) recorded at 45 broadband seismic stations from the Peruvian permanent and portable seismic networks as well as from, international networks (CTBTO, RSBR-Brazil, and RENSIG-Ecuador). The results reveal a complex anisotropy pattern with distinct variations in shear wave splitting along strike. In the northernmost region, the mean delay times range between 1.0 ± 0.2 s and 1.5 ± 0.2 s with fast directions predominantly oriented ENE-WSW approximately perpendicular to the trench, parallel with the motion of the subducting Nazca plate. In the central region of Peru, the predominant fast directions change to a SE-NW orientation that is oblique with the trench. These fast splitting directions are consistent with the pattern seen previously over the southern extent of the flat-slab and correlate well with the current geodetically derived motion of the overriding forearc, the Peruvian Sliver. These characteristics suggest a fundamental change in anisotropic behavior between the northern and central portions of the Peruvian flat-slab and imply that the upper plate deformation is a controlling factor.",
keywords = "Flat-slab subduction, Northern Peru, Seismic anisotropy, Shear wave splitting",
author = "Cristobal Condori and Fran{\c c}a, {George S.} and Tavera, {Hernando J.} and Eakin, {Caroline M.} and Colton Lynner and Beck, {Susan L.} and Villegas-Lanza, {Juan C.}",
note = "Funding Information: This study was supported by the Coordena{\c c}{\~a}o de Aperfei{\c c}oamento de Pessoal de N{\'i}vel Superior (CAPES - Brazil). We are thankful to J. Hu for providing the mantle flow model. We thank also the Peruvian (RENASIS) (https://portal.igp.gob.pe/red-sismica-nacional) from the Instituto Geof{\'i}sico del Per{\'u}, Brazilian (RSBR) (http://www.rsbr.gov.br/) and the Ecuadorian (EC) (https://www.igepn.edu.ec/red-nacional-de-sismografos) Seismographic Network for providing the seismological data. SplitLab is a free software package for teleseismic shear-wave splitting analysis developed by W{\"u}stefeld et al. (2008). A modified version of SplitLab by Robert Porritt was used for the analysis, and can be download here: https://robporritt.wordpress.com/software/. Maps were made with the GMT software (Wessel and Smith, 1998). GSF thanks CNPq for the PQ grants. Funding Information: This study was supported by the Coordena{\c c}{\~a}o de Aperfei{\c c}oamento de Pessoal de N{\'i}vel Superior (CAPES - Brazil) . We are thankful to J. Hu for providing the mantle flow model. We thank also the Peruvian (RENASIS) ( https://portal.igp.gob.pe/red-sismica-nacional ) from the Instituto Geof{\'i}sico del Per{\'u}, Brazilian (RSBR) ( http://www.rsbr.gov.br/ ) and the Ecuadorian (EC) ( https://www.igepn.edu.ec/red-nacional-de-sismografos ) Seismographic Network for providing the seismological data. SplitLab is a free software package for teleseismic shear-wave splitting analysis developed by W{\"u}stefeld et al. (2008) . A modified version of SplitLab by Robert Porritt was used for the analysis, and can be download here: https://robporritt.wordpress.com/software/ . Maps were made with the GMT software ( Wessel and Smith, 1998 ). GSF thanks CNPq for the PQ grants. Publisher Copyright: {\textcopyright} 2020 Elsevier Ltd",
year = "2021",
month = mar,
doi = "10.1016/j.jsames.2020.103053",
language = "English (US)",
volume = "106",
journal = "Journal of South American Earth Sciences",
issn = "0895-9811",
publisher = "Elsevier B.V.",
}