A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functions

Autores
Ammirati, Jean Baptiste; Alvarado, Patricia Monica; Beck, Susan
Año de publicación
2015
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
In the central Andes, the Nazca plate displays large along strike variations in dip with a near horizontal subduction angle between 28 and 32◦S referred to the Pampean flat slab segment. The upper plate above the Pampean flat slab has high rates of crustal seismicity and active basement cored uplifts. The SIEMBRA experiment, a 43-broad-band-seismic-station array was deployed to better characterize the Pampean flat slab region around 31◦S. In this study, we explore the lithospheric structure above the flat slab as a whole and its relation toseismicity. We use the SIEMBRA data to perform a joint inversion of teleseismic receiver functions and Rayleigh wave phase velocity dispersion to constrain the shear wave velocity variations in the lithosphere. Our joint inversion results show: (1) the presence of several upper-plate mid-crustal discontinuities and their lateral extent that are probably related to the terrane accretion history; (2) zones of high shear wave velocity in the upper-plate lower crust associated with a weak Moho signal consistent with the hypothesis of partial eclogitization in the lower crust; (3) the presence of low shear-wave velocities at ∼100 km depth interpreted as the subducting oceanic crust. Finally, in order to investigate the relation of the lithospheric structure to seismicity, we determine an optimal velocity?depth model based on the jointinversion results and use it to perform regional moment tensor inversions (SMTI) of crustal and slab earthquakes. The SMTI for 18 earthquakes that occurred between 2007 and 2009 in the flat slab region below Argentina, indicates systematically shallower focal depths for slab earthquakes (compared with inversions using previous velocity models). This suggests that the slab seismicity is concentrated mostly between 90 and 110 km depths within thesubducting Nazca plate?s oceanic crust and likely related to dehydration. In addition, the slab earthquakes exhibit extensional focal mechanisms suggesting new faulting at the edges of the flat portion of the slab. SMTI solutions for upper-plate crustal earthquakes match well the geological observations of reactivated structures and agree with crustal shortening. Our new constraints on flat slab structure can aid earthquake characterization for regional seismichazard assessment and efforts to help understand the mechanisms for slab flattening in the central Andes.
Fil: Ammirati, Jean Baptiste. Ministerio de Ciencia, Tecnología e Innovación Productiva. Agencia Nacional de Promoción Cientifíca y Tecnológica; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina
Fil: Alvarado, Patricia Monica. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Juan. Centro de Investigaciones de la Geosfera y Biosfera; Argentina
Fil: Beck, Susan. Arizona State University; Estados Unidos
Materia
Seismicity
Tectonics
Body Waves
Surface Waves
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/4871
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/4871
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functionsAmmirati, Jean BaptisteAlvarado, Patricia MonicaBeck, SusanSeismicityTectonicsBody WavesSurface Waveshttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1In the central Andes, the Nazca plate displays large along strike variations in dip with a near horizontal subduction angle between 28 and 32◦S referred to the Pampean flat slab segment. The upper plate above the Pampean flat slab has high rates of crustal seismicity and active basement cored uplifts. The SIEMBRA experiment, a 43-broad-band-seismic-station array was deployed to better characterize the Pampean flat slab region around 31◦S. In this study, we explore the lithospheric structure above the flat slab as a whole and its relation toseismicity. We use the SIEMBRA data to perform a joint inversion of teleseismic receiver functions and Rayleigh wave phase velocity dispersion to constrain the shear wave velocity variations in the lithosphere. Our joint inversion results show: (1) the presence of several upper-plate mid-crustal discontinuities and their lateral extent that are probably related to the terrane accretion history; (2) zones of high shear wave velocity in the upper-plate lower crust associated with a weak Moho signal consistent with the hypothesis of partial eclogitization in the lower crust; (3) the presence of low shear-wave velocities at ∼100 km depth interpreted as the subducting oceanic crust. Finally, in order to investigate the relation of the lithospheric structure to seismicity, we determine an optimal velocity?depth model based on the jointinversion results and use it to perform regional moment tensor inversions (SMTI) of crustal and slab earthquakes. The SMTI for 18 earthquakes that occurred between 2007 and 2009 in the flat slab region below Argentina, indicates systematically shallower focal depths for slab earthquakes (compared with inversions using previous velocity models). This suggests that the slab seismicity is concentrated mostly between 90 and 110 km depths within thesubducting Nazca plate?s oceanic crust and likely related to dehydration. In addition, the slab earthquakes exhibit extensional focal mechanisms suggesting new faulting at the edges of the flat portion of the slab. SMTI solutions for upper-plate crustal earthquakes match well the geological observations of reactivated structures and agree with crustal shortening. Our new constraints on flat slab structure can aid earthquake characterization for regional seismichazard assessment and efforts to help understand the mechanisms for slab flattening in the central Andes.Fil: Ammirati, Jean Baptiste. Ministerio de Ciencia, Tecnología e Innovación Productiva. Agencia Nacional de Promoción Cientifíca y Tecnológica; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; ArgentinaFil: Alvarado, Patricia Monica. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Juan. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Beck, Susan. Arizona State University; Estados UnidosWiley2015-03info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/4871Ammirati, Jean Baptiste; Alvarado, Patricia Monica; Beck, Susan; A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functions; Wiley; Geophysical Journal International; 202; 3-2015; 224-2410956-540Xenginfo:eu-repo/semantics/altIdentifier/url/http://gji.oxfordjournals.org/content/202/1/224.abstractinfo:eu-repo/semantics/altIdentifier/doi/10.1093/gji/ggv140info:eu-repo/semantics/altIdentifier/doi/info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-03T09:45:55Zoai:ri.conicet.gov.ar:11336/4871instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-03 09:45:56.045CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functions
title A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functions
spellingShingle A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functions
Ammirati, Jean Baptiste
Seismicity
Tectonics
Body Waves
Surface Waves
title_short A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functions
title_full A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functions
title_fullStr A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functions
title_full_unstemmed A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functions
title_sort A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functions
dc.creator.none.fl_str_mv Ammirati, Jean Baptiste
Alvarado, Patricia Monica
Beck, Susan
author Ammirati, Jean Baptiste
author_facet Ammirati, Jean Baptiste
Alvarado, Patricia Monica
Beck, Susan
author_role author
author2 Alvarado, Patricia Monica
Beck, Susan
author2_role author
author
dc.subject.none.fl_str_mv Seismicity
Tectonics
Body Waves
Surface Waves
topic Seismicity
Tectonics
Body Waves
Surface Waves
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv In the central Andes, the Nazca plate displays large along strike variations in dip with a near horizontal subduction angle between 28 and 32◦S referred to the Pampean flat slab segment. The upper plate above the Pampean flat slab has high rates of crustal seismicity and active basement cored uplifts. The SIEMBRA experiment, a 43-broad-band-seismic-station array was deployed to better characterize the Pampean flat slab region around 31◦S. In this study, we explore the lithospheric structure above the flat slab as a whole and its relation toseismicity. We use the SIEMBRA data to perform a joint inversion of teleseismic receiver functions and Rayleigh wave phase velocity dispersion to constrain the shear wave velocity variations in the lithosphere. Our joint inversion results show: (1) the presence of several upper-plate mid-crustal discontinuities and their lateral extent that are probably related to the terrane accretion history; (2) zones of high shear wave velocity in the upper-plate lower crust associated with a weak Moho signal consistent with the hypothesis of partial eclogitization in the lower crust; (3) the presence of low shear-wave velocities at ∼100 km depth interpreted as the subducting oceanic crust. Finally, in order to investigate the relation of the lithospheric structure to seismicity, we determine an optimal velocity?depth model based on the jointinversion results and use it to perform regional moment tensor inversions (SMTI) of crustal and slab earthquakes. The SMTI for 18 earthquakes that occurred between 2007 and 2009 in the flat slab region below Argentina, indicates systematically shallower focal depths for slab earthquakes (compared with inversions using previous velocity models). This suggests that the slab seismicity is concentrated mostly between 90 and 110 km depths within thesubducting Nazca plate?s oceanic crust and likely related to dehydration. In addition, the slab earthquakes exhibit extensional focal mechanisms suggesting new faulting at the edges of the flat portion of the slab. SMTI solutions for upper-plate crustal earthquakes match well the geological observations of reactivated structures and agree with crustal shortening. Our new constraints on flat slab structure can aid earthquake characterization for regional seismichazard assessment and efforts to help understand the mechanisms for slab flattening in the central Andes.
Fil: Ammirati, Jean Baptiste. Ministerio de Ciencia, Tecnología e Innovación Productiva. Agencia Nacional de Promoción Cientifíca y Tecnológica; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina
Fil: Alvarado, Patricia Monica. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Juan. Centro de Investigaciones de la Geosfera y Biosfera; Argentina
Fil: Beck, Susan. Arizona State University; Estados Unidos
description In the central Andes, the Nazca plate displays large along strike variations in dip with a near horizontal subduction angle between 28 and 32◦S referred to the Pampean flat slab segment. The upper plate above the Pampean flat slab has high rates of crustal seismicity and active basement cored uplifts. The SIEMBRA experiment, a 43-broad-band-seismic-station array was deployed to better characterize the Pampean flat slab region around 31◦S. In this study, we explore the lithospheric structure above the flat slab as a whole and its relation toseismicity. We use the SIEMBRA data to perform a joint inversion of teleseismic receiver functions and Rayleigh wave phase velocity dispersion to constrain the shear wave velocity variations in the lithosphere. Our joint inversion results show: (1) the presence of several upper-plate mid-crustal discontinuities and their lateral extent that are probably related to the terrane accretion history; (2) zones of high shear wave velocity in the upper-plate lower crust associated with a weak Moho signal consistent with the hypothesis of partial eclogitization in the lower crust; (3) the presence of low shear-wave velocities at ∼100 km depth interpreted as the subducting oceanic crust. Finally, in order to investigate the relation of the lithospheric structure to seismicity, we determine an optimal velocity?depth model based on the jointinversion results and use it to perform regional moment tensor inversions (SMTI) of crustal and slab earthquakes. The SMTI for 18 earthquakes that occurred between 2007 and 2009 in the flat slab region below Argentina, indicates systematically shallower focal depths for slab earthquakes (compared with inversions using previous velocity models). This suggests that the slab seismicity is concentrated mostly between 90 and 110 km depths within thesubducting Nazca plate?s oceanic crust and likely related to dehydration. In addition, the slab earthquakes exhibit extensional focal mechanisms suggesting new faulting at the edges of the flat portion of the slab. SMTI solutions for upper-plate crustal earthquakes match well the geological observations of reactivated structures and agree with crustal shortening. Our new constraints on flat slab structure can aid earthquake characterization for regional seismichazard assessment and efforts to help understand the mechanisms for slab flattening in the central Andes.
publishDate 2015
dc.date.none.fl_str_mv 2015-03
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/4871
Ammirati, Jean Baptiste; Alvarado, Patricia Monica; Beck, Susan; A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functions; Wiley; Geophysical Journal International; 202; 3-2015; 224-241
0956-540X
url http://hdl.handle.net/11336/4871
identifier_str_mv Ammirati, Jean Baptiste; Alvarado, Patricia Monica; Beck, Susan; A lithospheric velocity model for the flat slab region of Argentina from joint inversion of Rayleigh wave phase velocity dispersion and teleseismic receiver functions; Wiley; Geophysical Journal International; 202; 3-2015; 224-241
0956-540X
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/http://gji.oxfordjournals.org/content/202/1/224.abstract
info:eu-repo/semantics/altIdentifier/doi/10.1093/gji/ggv140
info:eu-repo/semantics/altIdentifier/doi/
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Wiley
publisher.none.fl_str_mv Wiley
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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