Programa de Pós-Graduação em Geofísica - CPGF/IG
URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2355
O Programa de Pós-Graduação em Geofísica da UFPA (CPGF) do Instituto de Geociências (IG) da Universidade Federal do Pará (UFPA). Foi o segundo no Brasil a formar recursos humanos em Geofísica em nível de pós-graduação stricto sensu. Criado em 1972, funcionou até 1992 junto com os Cursos de Pós-Graduação em Geoquímica e Geologia.
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Item Acesso aberto (Open Access) Inversão 1D e 2D de dados do método eletromagnético a multi-frequência - EMMF(Universidade Federal do Pará, 2014-11-14) PIEDADE, Anderson Almeida da; RÉGIS, Cícero Roberto Teixeira; http://lattes.cnpq.br/7340569532034401In this work is presented the rst study of data inversion from Electromagnetic Multi- Frequency Method (EMMF). In its rst part is made a presentation of the mathematical techniques used for inversion of these data. It will be shown the Gauss-Newton technique with modied Marquardt algorithm and a description of two regularization methods used in the inversion, which are Global Smoothness method (GS) and Total Variation method (TV). In the second part, they are applied to 1D inversion of EMMF synthetic data as well as are applied to real data, that were acquired in the Esprito Santo Basin, southeastern Brazil. In the third and last part, it presented the 2D inversion of EMMF synthetic data, with models, which like the 1D inversion, involving conductive and resistive targets. Results of this study show that the inversion of data from conductive targets was able to recover the resistivity structures more consistently with the true resistivity model than in the case of resistive targets. This may be due to the fact that the purely inductive radial magnetic component is naturally more strongly in uenced by conductive than by resistive regions in the geoelectrical medium.Item Acesso aberto (Open Access) Modelagem numérica bidimensional de dados CSAMT com fonte dipolar elétrica usando elementos finitos(Universidade Federal do Pará, 2016-08-20) PEREZ, Jarol David Garcia; SILVA, Valdelírio da Silva e; http://lattes.cnpq.br/9701131346395521; RÉGIS, Cícero Roberto Teixeira; http://lattes.cnpq.br/7340569532034401This work presents the application of a 2,5D numerical modelling scheme to simulate data of the CSAMT (Controlled Source Audio MagnetoTellurics) electromagnetic method using the Finite Element method. We have applied the technique of separating the total electromagnetic field into two parts: the so called primary and secondary fields. The set of equations that govern the system has to be expressed in the spectral domain of the Fourier Transform. The solution is obtained as a composition of 2D solutions. In the first part of the dissertation, we present a validation of the answer generated for primary fields and a comparison of the 1D responses with those from the MT method. The second part of the text presents a validation of the 2,5D responses, as well as an analysis of the results, in terms of apparent resistivity and the measured electrical field related to an isolated body in a homogeneous half-space. We analyze the changes in the results resulting from changes in model parameters like the contrast of resistividade between the half-space and the anomalous body, the depth of the body and the frequency. The code developed is able to simulate with good precision the measurements of the CSAMT method in any survey configuration.