@MastersThesis{Vieira:2020:EsTaDe,
author = "Vieira, Lucas de Brito",
title = "Estimativa de taxas de deforma{\c{c}}{\~a}o tect{\^o}nica para
a parte central da placa tect{\^o}nica Sul-Americana com base em
s{\'e}ries temporais GNSS",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2020",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2020-03-13",
keywords = "esta{\c{c}}{\~o}es GNSS, placa tect{\^o}nica Sul-Americana,
estimativa de velocidade, taxas de deforma{\c{c}}{\~a}o
tect{\^o}nica, mecanismos focais, GNSS stations, South American
tectonic plate, velocity estimation, tectonic strain rates, focal
mechanism.",
abstract = "Este trabalho teve por objetivo determinar as taxas de
deforma{\c{c}}{\~a}o tect{\^o}nica no interior da placa
tect{\^o}nica sul-americana a partir de estimativas de
velocidades de esta{\c{c}}{\~o}es GNSS. Para esse
prop{\'o}sito, foram selecionadas 63 esta{\c{c}}{\~o}es com
cerca de 10 anos de dados pertencentes {\`a} rede SIRGAS-C. As
velocidades dessas esta{\c{c}}{\~o}es foram estimadas de acordo
com metodologias baseadas no M{\'e}todo dos M{\'{\i}}nimos
Quadrados (MMQ) e no estimador de tend{\^e}ncias mediana MIDAS.
As velocidades estimadas apresentaram valores de cerca de 13,90
mm/ano (MMQ) e 11,49 mm/ano (MIDAS) e orienta{\c{c}}{\~a}o
preferencialmente para NO no interior da placa da Am{\'e}rica do
Sul, sendo as estimativas do MMQ mais precisas que as estimativas
do MIDAS. As taxas de deforma{\c{c}}{\~a}o tect{\^o}nica foram
calculadas a partir das velocidades estimadas pelos dois
m{\'e}todos usando as abordagens do VISR (c{\'e}lulas de
Voronoi), GeoStrain (coloca{\c{c}}{\~a}o por m{\'{\i}}nimos
quadrados) e Strain_GNSS (triangula{\c{c}}{\~a}o de Delaunay).
Em geral, as taxas de deforma{\c{c}}{\~a}o tect{\^o}nica
calculadas foram da ordem de -1,17 nanostrain/ano (MMQ) e -0,74
nanostrain/ano (MIDAS) para o VISR, -2,83 nanostrain/ano (MMQ) e
-1,18 nanostrain/ano (MIDAS) para o GeoStrain e -9,60x10-7
strain/ano (MMQ) e -4,20x10-6 strain/ano (MIDAS) para o
Strain_GNSS, com taxas orientadas para NL-SO, NO-SL e L-O em
diferentes regi{\~o}es da placa para os tr{\^e}s m{\'e}todos.
Com exce{\c{c}}{\~a}o dos c{\'a}lculos com o Strain_GNSS, as
taxas de dilata{\c{c}}{\~a}o mostraram predom{\'{\i}}nio de
compress{\~a}o na maior parte da intraplaca sul-americana, com
dom{\'{\i}}nios de extens{\~a}o localizados na regi{\~a}o
nordeste, no caso do VISR, e ao longo de toda margem Equatorial
Atl{\^a}ntica, no caso do GeoStrain. Compara{\c{c}}{\~o}es com
mecanismos focais sugerem boa concord{\^a}ncia entre o campo de
deforma{\c{c}}{\~a}o calculado e o campo de tens{\~o}es para
v{\'a}rios dom{\'{\i}}nios tect{\^o}nicos da intraplaca
sul-americana. Por{\'e}m, uma dire{\c{c}}{\~a}o NO-SL indicada
pelos mecanismos focais para a parte central da placa e
estendendo-se para a regi{\~a}o amaz{\^o}nica n{\~a}o {\'e}
modelada por nenhuma das t{\'e}cnicas aqui utilizadas. Uma
densidade maior de esta{\c{c}}{\~o}es GNSS, com tempos de
opera{\c{c}}{\~a}o mais longos, {\'e} necess{\'a}ria para
melhorar a qualidade dos resultados. ABSTRACT: This work aimed to
determine tectonic deformation rates in the inner part the South
American tectonic plate based on velocity estimates of GNSS
stations. Sixty tree stations with about 10 years of data
belonging to the SIRGAS-C network were selected. The velocities of
these stations were estimated using the Least Squares Method (LSM)
and the MIDAS median trend estimator. The estimated velocities
showed values of about 13.90 mm/year (LSM) and 11.49 mm/year
(MIDAS) and a NW preferred orientation inside the South American
plate, with LSM estimates being more accurate than the MIDAS
estimates. Tectonic strain rates were calculated from the
velocities estimated by the two methods using the VISR (Voronoi
cells), GeoStrain (least squares placement) and Strain_GNSS
(Delaunay triangulation) approaches. The calculated tectonic
strain rates were in the range \−1.17 nanostrain/year (LSM)
and \−0.74 nanostrain/year (MIDAS) for VISR, \−2.83
nanostrain/year (LSM) and \−1.18 nanostrain/year (MIDAS)
for GeoStrain and \−9.60x10-7 strain/year (LSM) and
\−4.20x10-6 strain/year (MIDAS) for Strain_GNSS, with rates
oriented to NESW, NW-SE and EW in different regions for the three
methods. With the exception of calculations with Strain_GNSS,
dilatation rates showed a predominance of compression in most of
the South American intraplate, with extension domains located in
the northeast region, in the case of VISR, and along the entire
Atlantic Equatorial margin, in the case of GeoStrain. Comparisons
with focal mechanisms suggest good agreement between the
calculated strain field and the stress field for various tectonic
domains of the South American intraplate. However, an NW-SE
direction indicated by the focal mechanisms for the central part
of the plate and extending toward the Amazon region is not modeled
by any of the techniques used here. A higher density of GNSS
stations, with longer operating times, is necessary to improve the
quality of the results.",
committee = "Wrasse, Cristiano Max (presidente) and Padilha, Antonio Lopes
(orientador) and Marques, Haroldo Antonio (orientador) and Paula,
Eurico Rodrigues de and Marotta, Guliano Sant'Anna",
englishtitle = "Estimation of tectonic strain rates for the central part of the
South American tectonic plate based on GNSS time series",
language = "pt",
pages = "84",
ibi = "8JMKD3MGP3W34R/422F67E",
url = "http://urlib.net/ibi/8JMKD3MGP3W34R/422F67E",
targetfile = "publicacao.pdf",
urlaccessdate = "24 abr. 2024"
}