2-DIMENSIONAL MAGNETOTELLURIC MODELING USING FINITE ELEMENT NODE-BASED METHOD WITH DIRECT AND ITERATIVE ALGORITHMS

• Main Author: Amelia Marianto Limbong, Gita
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/81534
• Institution: Institut Teknologi Bandung

Magnetotellurics (MT) is a passive geophysical exploration technique that utilizes natural electromagnetic wave sources to determine subsurface resistivity and phase structures. Two-dimensional magnetotelluric modeling is employed to obtain the distribution of apparent resistivity and impedance phase. This modeling uses the finite element node-based method, which divides the domain into irregular two-dimensional triangular elements and solves Maxwell’s equations for each element. The modeling involves both homogeneous and layered earth models and is applied to two modes: Transverse Electric (TE) and Transverse Magnetic (TM). This study employs three types of matrixsolving algorithms within the finite element node-based method: matrix decomposition, conjugate gradient, and bi-conjugate gradient. The results of the modeling provide the distribution of apparent resistivity and impedance phase in a two-dimensional earth structure. Analytical results are used as a reference to verify the two-dimensional modeling program. The study results indicate that the error in apparent resistivity and impedance phase for both homogeneous and layered earth models for each matrixsolving algorithm is less than 3%. Additionally, the most efficient iteration time was achieved using the matrix decomposition algorithm.