Identifying Geological Fault Structures Using GGMplus Satellite Data and Derivative Methods to Characterize Mount Endut Geothermal Systems via 3D-Inversion Gravity Modeling

The geological map shows that the Mount Endut area possesses a geothermal system, which is suggested by the presence of geothermal surface manifestations: the Cikawah and Handeleum hot springs. The existence of a subsurface geological fault structure along the manifestations creates good permeability for the geothermal reservoir. The purpose of this study was to utilize Global Gravity Model plus (GGMplus) gravity satellite data to prove the existence of a geological fault structure around the manifestation area with the first horizontal derivative (FHD) and second vertical derivative (SVD) methods; then, we developed a conceptual model of the geothermal system from the 3D-inversion gravity method. Results show a cap suspected of being clay, with a density of 2.52–2.58 g/cm3 at depth of 0–1250 m. The reservoir layer was suspected to be lava rock with a density of 2.60–2.66 g/cm3 at a depth of 1500–3000 m; also, the heat source layer was suspected to be an igneous intrusion with a density of 2.70–2.72 g/cm3 at depth of 1750–3000 m.