Two-Dimensional (2-D) Modeling of Magnetotelluric Field Data (Papandayan Field Data) Using Edge Finite-Element Method
Lisa- Yihaa Roodhiyah (a*), Tiffany Tjong (a), Nurhasan (a), D Sutarno (a)
(a) Electromagnetic Induction Lab., Physics of Complex System Div., Faculty of Mathematics and Natrural Sciences, Bandung Institute of Technology, Jalan Ganesha 10, Bandung 40132, Indonesia
*lisa_yihaa[at]s.itb.ac.id
Abstract
Edge finite element (vector finite element) which is solved using sparse direct solver (PARDISO) has been used in this paper to model 2-D magnetotelluric field data (Papandayan field data). The site sounding of the field data which is used on this modeling are 10 site soundings. The focus of this paper is on the using 2-D magnetoteluric modeling scheme which is developed to model field data. First, the generating mesh to the field data and choosing the appropriate model are reviewed. Normalize coordinate to get the zero point before the meshing step is important so that the sensitivity matrices did not contain big amount of number which computationally can cause error in calculating matrices. Prior information needed to define the appropriate model. Second, the accuracy of the modeling result (apparent resistivity and phase) is compared to field data. In the end, it has shown that the modeling result has a good agreement with the field data which shows that there are divided by three areas with different resistivity. In the shallow depth (<1500 m) are dominated with low resistivity (around 5 Ωm). Next, the resistivity increases within the depth in 1500m until 3200m which are 150 Ωm until 300 Ωm. Then, finally the resistivity decreased in the deep depth (>3200 m) which around 3 Ωm.
Keywords: field data, magnetotelluric modeling, two-dimensional modeling, vector finite element, edge finite element, sparse direct solver
Topic: Electromagnetic Methods