New measurements of crustal and lithospheric thickness for the South American platform using the receiver function method, toward a 3D velocity model
Autor(a) principal: | |
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Data de Publicação: | 2021 |
Tipo de documento: | Tese |
Idioma: | eng |
Título da fonte: | Biblioteca Digital de Teses e Dissertações da USP |
Texto Completo: | https://www.teses.usp.br/teses/disponiveis/14/14132/tde-15092021-124822/ |
Resumo: | Using the Permanent Brazilian Network and a temporary deployment, we studied the Moho discontinuity and the Lithosphere-Asthenosphere Boundary (LAB) in the stable South American platform. From P-wave receiver functions processed with a modified, low uncertainty, H-k stacking method, we obtained the Moho depth; that together with previous results permitted to updated the crustal thickness map of South America, with improved resolution in the Amazon and western part of Brazil, and better delimiting the narrow belt of thinner Sub-Andean crust. The average crustal thickness in the stable continental region is 40.5 km. Paraná and Parnaba intracratonic Basins, the western part of Pantanal Basin and Amazon Craton present a thicker crust up to 44 km. The eastern edge of Pantanal Basin, Borborema, and Mantiqueira Provinces present a thinner crust, up to 36 km. Vp/Vs ratios were estimated for the first time on a large scale in the South American platform. Values ranged between 1.68 and 1.80, being higher in the Paraná Basin and coastal margin (up to 1.79) and lower in cratonic areas (< 1.74). Nevertheless, regional patterns are hard to establish due to the scattered estimations. The LAB was estimated using the S-wave receiver function method, also analyzing some local international stations. At the Borborema and Mantiqueira Provinces, we confirm a thinner lithosphere of 90 km that also characterizes the Chaco and Pantanal Basins. The Amazon Craton, the São Francisco Craton, and Paranapanema block present a thicker, greater than 120 km lithosphere; in these older and colder areas, we also interpreted a mid-lithospheric discontinuity at 90 km, which tends to correlate with the heat flow. Nevertheless, we do not observe a clear correlation between the heat flow and deeper LAB measurements. On the other hand, the seismicity follows areas with thinner observed lithosphere. Finally, due to the need of using 3D velocity models for regional accurate epicenter locations, that improves neotectonic and seismic hazard studies, we have built a 3D a-priori velocity model for the South American Platform including the Central Andes area. The model is based on previous velocity relationships and structural information, being the most important the obtained crustal thickness. The horizontal resolution is 0.5º, and the vertical varies from 1 km at shallower depths to 5 km in the upper mantle. The travel time difference between the 3D and 1D velocity models is larger than 8 seconds for a station on the stable platform predicting an Andean event travel time. To test the model reliability, we relocated the well-known Aiquile 1998 earthquake (Bolivia) and recent platform events, obtaining successful results when compared with the best epicenters. |
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New measurements of crustal and lithospheric thickness for the South American platform using the receiver function method, toward a 3D velocity modelNovas estimativas de espessura crustal e litosférica na plataforma Sul-Americana usando o método de função do receptor, para um modelo de velocidade 3D.3D velocity modelCrustal thicknessEspessura crustalFunção de receptor da onda P e SLimite litosfera-astenosferaLithosphere-Asthenosphere boundaryModelo de velocidade 3DP-wave receiver functionPlataforma Sul-Americana.S-wave receiver functionSouth America platform.Using the Permanent Brazilian Network and a temporary deployment, we studied the Moho discontinuity and the Lithosphere-Asthenosphere Boundary (LAB) in the stable South American platform. From P-wave receiver functions processed with a modified, low uncertainty, H-k stacking method, we obtained the Moho depth; that together with previous results permitted to updated the crustal thickness map of South America, with improved resolution in the Amazon and western part of Brazil, and better delimiting the narrow belt of thinner Sub-Andean crust. The average crustal thickness in the stable continental region is 40.5 km. Paraná and Parnaba intracratonic Basins, the western part of Pantanal Basin and Amazon Craton present a thicker crust up to 44 km. The eastern edge of Pantanal Basin, Borborema, and Mantiqueira Provinces present a thinner crust, up to 36 km. Vp/Vs ratios were estimated for the first time on a large scale in the South American platform. Values ranged between 1.68 and 1.80, being higher in the Paraná Basin and coastal margin (up to 1.79) and lower in cratonic areas (< 1.74). Nevertheless, regional patterns are hard to establish due to the scattered estimations. The LAB was estimated using the S-wave receiver function method, also analyzing some local international stations. At the Borborema and Mantiqueira Provinces, we confirm a thinner lithosphere of 90 km that also characterizes the Chaco and Pantanal Basins. The Amazon Craton, the São Francisco Craton, and Paranapanema block present a thicker, greater than 120 km lithosphere; in these older and colder areas, we also interpreted a mid-lithospheric discontinuity at 90 km, which tends to correlate with the heat flow. Nevertheless, we do not observe a clear correlation between the heat flow and deeper LAB measurements. On the other hand, the seismicity follows areas with thinner observed lithosphere. Finally, due to the need of using 3D velocity models for regional accurate epicenter locations, that improves neotectonic and seismic hazard studies, we have built a 3D a-priori velocity model for the South American Platform including the Central Andes area. The model is based on previous velocity relationships and structural information, being the most important the obtained crustal thickness. The horizontal resolution is 0.5º, and the vertical varies from 1 km at shallower depths to 5 km in the upper mantle. The travel time difference between the 3D and 1D velocity models is larger than 8 seconds for a station on the stable platform predicting an Andean event travel time. To test the model reliability, we relocated the well-known Aiquile 1998 earthquake (Bolivia) and recent platform events, obtaining successful results when compared with the best epicenters.Utilizando a Rede Sismográfica Brasileira e as estações temporárias XC, estudamos a descontinuidade de Moho e o limite litosfera-astenosfera (LAB - Lithosphere-Asthenosphere Boundary) na plataforma Sul-Americana. A espessura crustal foi obtida a partir das funções do receptor da onda P, empilhadas com o método H-k modificado, que fornece incertezas menores; estas estimativas junto com dados previamente publicados permitiram atualizar o mapa de espessura crustal para a América do Sul, melhorando a resolução na região Amazônica e no oeste do Brasil, e delimitando melhor a faixa estreita de crosta fina da região Sub-Andina. A média da espessura crustal na plataforma do continente é de 40.5 km. As bacias do Paraná e Parnaba, a parte oeste da bacia do Pantanal e o Cráton Amazônico apresentam uma crosta espessa de até 44 km. A borda leste da bacia do Pantanal, e as províncias de Borborema e Mantiqueira apresentam uma crosta mais fina de 36 km. As razões de Vp/Vs foram estimadas pela primeira vez em grande escala na plataforma Sul-Americana; os valores obtidos variam entre 1,68 e 1,80, sendo mais altos na Bacia do Paraná e na margem costeira (até 1,79), e menores em áreas cratônicas (<1,74). Entretanto, é difícil estabelecer padrões regionais devido às estimativas dispersas. A LAB foi estimada a partir das funções do receptor da onda S e também foram analisadas estações internacionais locais. Nas províncias da Borborema e Mantiqueira foi confirmada uma litosfera mais fina de 90 km, assim como nas Bacias do Chaco e Pantanal. Nos crátons Amazônico, São Francisco e no bloco Paranapanema foi observada uma litosfera mais espessa que 120 km; nestas áreas mais antigas e com um fluxo térmico menor foi identificada uma outra descontinuidade litosférica em 90 km, que tende a se correlacionar com o fluxo térmico. No entanto, não foi observada uma correlação clara entre o fluxo térmico e as medidas da LAB mais profundas. Por outro lado, a sismicidade parece ser maior em áreas que apresentam uma litosfera mais fina. Devido à necessidade de se utilizar modelos de velocidade 3D para localizações precisas em escala regional, e poder melhorar os estudos neotectônicos e de ameaça ssmica, foi construdo um modelo de velocidade a-priori 3D para a plataforma Sul-Americana que também inclui os Andes Centrais. O modelo está baseado em relações de velocidades e informações estruturais previamente publicadas, sendo uma das mais importantes a espessura crustal obtida com as funções do receptor da onda P. A resolução horizontal é de 0.5º, e a vertical varia de 1 km na região mais superficial até 5 km no manto superior. A diferença dos tempos de percurso quando usamos modelos de velocidade 3D e 1D é de até 8 segundos para estações na plataforma estável que preveem tempos de percurso de eventos andinos. Para testar a confiabilidade do modelo, relocalizamos o sismo de Aiquile (Bolívia) e dois eventos mais recentes da plataforma estável, obtendo resultados satisfatórios.Biblioteca Digitais de Teses e Dissertações da USPBianchi, Marcelo Belentani deVera, Julia Carolina Rivadeneyra2021-06-09info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfhttps://www.teses.usp.br/teses/disponiveis/14/14132/tde-15092021-124822/reponame:Biblioteca Digital de Teses e Dissertações da USPinstname:Universidade de São Paulo (USP)instacron:USPLiberar o conteúdo para acesso público.info:eu-repo/semantics/openAccesseng2021-09-22T17:51:02Zoai:teses.usp.br:tde-15092021-124822Biblioteca Digital de Teses e Dissertaçõeshttp://www.teses.usp.br/PUBhttp://www.teses.usp.br/cgi-bin/mtd2br.plvirginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.bropendoar:27212021-09-22T17:51:02Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)false |
dc.title.none.fl_str_mv |
New measurements of crustal and lithospheric thickness for the South American platform using the receiver function method, toward a 3D velocity model Novas estimativas de espessura crustal e litosférica na plataforma Sul-Americana usando o método de função do receptor, para um modelo de velocidade 3D. |
title |
New measurements of crustal and lithospheric thickness for the South American platform using the receiver function method, toward a 3D velocity model |
spellingShingle |
New measurements of crustal and lithospheric thickness for the South American platform using the receiver function method, toward a 3D velocity model Vera, Julia Carolina Rivadeneyra 3D velocity model Crustal thickness Espessura crustal Função de receptor da onda P e S Limite litosfera-astenosfera Lithosphere-Asthenosphere boundary Modelo de velocidade 3D P-wave receiver function Plataforma Sul-Americana. S-wave receiver function South America platform. |
title_short |
New measurements of crustal and lithospheric thickness for the South American platform using the receiver function method, toward a 3D velocity model |
title_full |
New measurements of crustal and lithospheric thickness for the South American platform using the receiver function method, toward a 3D velocity model |
title_fullStr |
New measurements of crustal and lithospheric thickness for the South American platform using the receiver function method, toward a 3D velocity model |
title_full_unstemmed |
New measurements of crustal and lithospheric thickness for the South American platform using the receiver function method, toward a 3D velocity model |
title_sort |
New measurements of crustal and lithospheric thickness for the South American platform using the receiver function method, toward a 3D velocity model |
author |
Vera, Julia Carolina Rivadeneyra |
author_facet |
Vera, Julia Carolina Rivadeneyra |
author_role |
author |
dc.contributor.none.fl_str_mv |
Bianchi, Marcelo Belentani de |
dc.contributor.author.fl_str_mv |
Vera, Julia Carolina Rivadeneyra |
dc.subject.por.fl_str_mv |
3D velocity model Crustal thickness Espessura crustal Função de receptor da onda P e S Limite litosfera-astenosfera Lithosphere-Asthenosphere boundary Modelo de velocidade 3D P-wave receiver function Plataforma Sul-Americana. S-wave receiver function South America platform. |
topic |
3D velocity model Crustal thickness Espessura crustal Função de receptor da onda P e S Limite litosfera-astenosfera Lithosphere-Asthenosphere boundary Modelo de velocidade 3D P-wave receiver function Plataforma Sul-Americana. S-wave receiver function South America platform. |
description |
Using the Permanent Brazilian Network and a temporary deployment, we studied the Moho discontinuity and the Lithosphere-Asthenosphere Boundary (LAB) in the stable South American platform. From P-wave receiver functions processed with a modified, low uncertainty, H-k stacking method, we obtained the Moho depth; that together with previous results permitted to updated the crustal thickness map of South America, with improved resolution in the Amazon and western part of Brazil, and better delimiting the narrow belt of thinner Sub-Andean crust. The average crustal thickness in the stable continental region is 40.5 km. Paraná and Parnaba intracratonic Basins, the western part of Pantanal Basin and Amazon Craton present a thicker crust up to 44 km. The eastern edge of Pantanal Basin, Borborema, and Mantiqueira Provinces present a thinner crust, up to 36 km. Vp/Vs ratios were estimated for the first time on a large scale in the South American platform. Values ranged between 1.68 and 1.80, being higher in the Paraná Basin and coastal margin (up to 1.79) and lower in cratonic areas (< 1.74). Nevertheless, regional patterns are hard to establish due to the scattered estimations. The LAB was estimated using the S-wave receiver function method, also analyzing some local international stations. At the Borborema and Mantiqueira Provinces, we confirm a thinner lithosphere of 90 km that also characterizes the Chaco and Pantanal Basins. The Amazon Craton, the São Francisco Craton, and Paranapanema block present a thicker, greater than 120 km lithosphere; in these older and colder areas, we also interpreted a mid-lithospheric discontinuity at 90 km, which tends to correlate with the heat flow. Nevertheless, we do not observe a clear correlation between the heat flow and deeper LAB measurements. On the other hand, the seismicity follows areas with thinner observed lithosphere. Finally, due to the need of using 3D velocity models for regional accurate epicenter locations, that improves neotectonic and seismic hazard studies, we have built a 3D a-priori velocity model for the South American Platform including the Central Andes area. The model is based on previous velocity relationships and structural information, being the most important the obtained crustal thickness. The horizontal resolution is 0.5º, and the vertical varies from 1 km at shallower depths to 5 km in the upper mantle. The travel time difference between the 3D and 1D velocity models is larger than 8 seconds for a station on the stable platform predicting an Andean event travel time. To test the model reliability, we relocated the well-known Aiquile 1998 earthquake (Bolivia) and recent platform events, obtaining successful results when compared with the best epicenters. |
publishDate |
2021 |
dc.date.none.fl_str_mv |
2021-06-09 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://www.teses.usp.br/teses/disponiveis/14/14132/tde-15092021-124822/ |
url |
https://www.teses.usp.br/teses/disponiveis/14/14132/tde-15092021-124822/ |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
|
dc.rights.driver.fl_str_mv |
Liberar o conteúdo para acesso público. info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Liberar o conteúdo para acesso público. |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.coverage.none.fl_str_mv |
|
dc.publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
dc.source.none.fl_str_mv |
reponame:Biblioteca Digital de Teses e Dissertações da USP instname:Universidade de São Paulo (USP) instacron:USP |
instname_str |
Universidade de São Paulo (USP) |
instacron_str |
USP |
institution |
USP |
reponame_str |
Biblioteca Digital de Teses e Dissertações da USP |
collection |
Biblioteca Digital de Teses e Dissertações da USP |
repository.name.fl_str_mv |
Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP) |
repository.mail.fl_str_mv |
virginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.br |
_version_ |
1809090751884165120 |