SUBSURFACE STRUCTURE IDENTIFICATION OF LEMBANG FAULT USING MAGNETIC METHOD (CASE STUDY : LANGENSARI, LEMBANG, WEST BANDUNG REGENCY)

• Main Author: Krisnanto, Fery
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/50367
• Institution: Institut Teknologi Bandung

As a country located on the plate boundary, Indonesia is blessed with various geological structures; one of them is a fault. Active faults can cause earthquakes; thus, fault structures identification is needed for disaster mitigation. Among the many faults in Indonesia, Lembang Fault, located in north Bandung, which extends 22 km from Padalarang to Mount Manglayang. In this study, identification of the Lembang fault (Langensari region/segment) was carried out. This research used the magnetic method, which is one of the geophysical methods to detect subsurface structures by mapping the susceptibility of rocks. Data acquisition was performed using a Geometrics G-856AX magnetometer. The magnetic field data was taken at 46 measurement points with space from 50 meters to 100 meters across the Lembang Fault. The measured data are total magnetic fields corrected with daily corrections and IGRF corrections, resulting in anomalous data that shows the magnetic susceptibility of subsurface rocks. Modelling is done by using forward and inversion. The result of modelling indicates differences in magnetic susceptibility in the north and south of the fault. The Tangkubanparahu pyroclastic deposits dominate the northern part, and the southern part is dominated by Tangkubanparahu and Sunda lava, as well as sagpond deposits composed of clay to the north of the fault line.