Two-dimensional magnetotelluric inversion using unstructured triangular mesh implemented in Julia Dieno Diba (a), Nurhasan (b*), Makoto Uyeshima(a), and Yoshiya Usui(a)
a) Earthquake Research Institute, the University of Tokyo, 1 - 1 - 1 Yayoi, Bunkyo, Tokyo 113-0032, Japan
b) Physics Department, Bandung Institute of Technology, Jl. Ganesa No.10, Bandung, West Java 40132, Indonesia
*nurhasan[at]itb.ac.id
Abstract
We have developed a 2-D magnetotelluric inversion code tailored for unstructured triangular meshes, developed using Julia, a high-level, high-performance programming language designed for scientific and numerical computation. The forward modeling engine utilizes a node-based finite element method to solve electromagnetic fields throughout the modeling domain. The inversion process employs the Gauss-Newton optimization algorithm, iteratively updating the model via the minimization of a regularized least-squares objective function. We verified the accuracy of the forward modeling using two reference models and performed a synthetic inversion experiment to validate our inversion method and stress the necessity of accurately handling topography-influenced data. Through its application to constructing an electrical resistivity model beneath the northwestern end of Sumatra Island, Indonesia, we demonstrated the practicality of our code for inverting field datasets.
