Resistivity Distribution of Lembang Fault Based on Magnetotelluric Data
Muhammad Risyad Naufal (a), Nurhasan (a*), Wahyu Srigutomo (a), Enjang jaenal Mustopa (a), Dieno Diba (b), Yasuo Ogawa (c), Qhathrin Nada (a), Randi Rusdiana (a)

a) Earth Physics and Complex Systems Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia
*nurhasan[at]fi.itb.ac.id

b) Earthquake Research Institute, the University of Tokyo, 1 - 1 - 1 Yayoi, Bunkyo, Tokyo 113-0032, Japan

c)Volcanic Fluid Research Center, Tokyo Institute of Technology, Tokyo, Japan

Abstract

An Earthquake is a geological phenomenon that happens due to tectonic activity. One of the causes of earthquakes is due to faults that move continuously. Lembang fault located 15 Km north of Bandung city is one of the potential sources of earthquakes in Indonesia. In this study, the Magnetotelluric method was used to model the subsurface resistivity at the Lembang Fault area. The data acquisition was conducted in 9 points of measurement path, perpendicular to the Lembang Fault. The analysis was performed using apparent resistivity data using three different frequencies which are 115 Hz, 11.2 Hz, and 1.02 Hz and inversion modeling was carried out using the finite element method. The result showed that the apparent resistivity decreases significantly in the area of the Lembang Fault. The inversion results show resistivity contrasts around the LMB02 point that is suspected to be the Lembang Fault. These results are consistent with geological data in the Lembang Fault area. Aside from the LMB02 point, there are also resistivity contrasts around the LMB05 point. However, from a geological perspective, it is not yet known whether the area around the LMB05 point represents a fault or another geological structure.

Keywords: Lembang Fault, Magnetotelluric, Earthquake, Inversion Modelling

Topic: Earth and Planetary Sciences