Dimensionally adaptive hp-finite element simulation and inversion of 2D magnetotelluric measurements

Magnetotelluric (MT) problems often contain different subdomains where the conductivity of the media depends upon one, two, or three spatial variables. Traditionally, when a MT problem incorporates a three-dimensional (3D) subdomain, the numerical method employed for simulation and inversion was 3D...

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Detalles Bibliográficos
Autores: Alvarez Aramberri, Julen, Pardo Zubiaur, David
Tipo de recurso: artículo
Fecha de publicación:2016
País:España
Institución:Universidad del País Vasco
Repositorio:Addi. Archivo Digital para la Docencia y la Investigación
OAI Identifier:oai:dnet:addi________::5e253bde4e11b9f143f27563c84e7c4a
Acceso en línea:http://hdl.handle.net/10810/78876
Access Level:acceso abierto
Palabra clave:dimensionally adaptive method
magnetotelluric problem
finite element method (FEM)
hp-adaptivity
inverse problems
Descripción
Sumario:Magnetotelluric (MT) problems often contain different subdomains where the conductivity of the media depends upon one, two, or three spatial variables. Traditionally, when a MT problem incorporates a three-dimensional (3D) subdomain, the numerical method employed for simulation and inversion was 3D over the entire domain. In here, we propose to take advantage of the possibly lower dimensionality of certain subdomains during the inversion process. By doing so, we obtain significant computational savings (up to 75% in some scenarios) and increased accuracy on the results. We numerically illustrate this method by employing two dimensional (2D) computations based on a multi-goal oriented hp-adaptive Finite Element Method (FEM) that exhibits superior convergence properties. Additionally, we provide a formulation for implementing an efficient adjoint based method for the computation of the derivatives of the impedance, and we show the importance of the (a) proper selection of the inversion variable, and (b) the advantages of using both the Transverse Electric (TE) and Transverse Magnetic (TM) measurements for the proper inversion of MT data.