MODELLING SUBSURFACE STRUCTURE BASED ON MAGNETIK DATA TO IDENTIFY THE PRESENCE OF MAAR LAKE: CASE STUDY OF SETUPATOK RESERVOIR AREA, CIREBON DISTRICT

• Main Author: Muchamad Zainulwafa, Ahmad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86075
• Institution: Institut Teknologi Bandung

Maar lakes are formed from a series of small-scale eruptions, which occur when magma rises to the surface. Subsequently, the magma comes into contact with the groundwater surface and produces phreatomagmatic explosions in the subsurface. Understanding the subsurface structure of maar lakes can be done, one of which is through the use of magnetic methods to model the subsurface structure. This research uses magnetic methods to obtain a subsurface structure model. Before modelling is done, the magnetic data is corrected first. This correction consists of diurnal correction and IGRF correction. Then, forward modelling was carried out with the help of Oasis Montaj software. In this study, the susceptibility value used has a value range of 0.000166 cm³/g - 0.005940 cm³/g. Modelling was done by making three passes with a magnetic method error range of 8.905 nT - 13.006 nT. From the modelling that has been done, the resulting subsurface structure is in accordance with the geological conditions. Based on these results, the research location identified a maar lake, which is buried by the rock unit of Careme Young Volcanic Products.