Evaluation of the shallow hydrothermal system in Jaboi Volcano based on the combination of remote sensing and geophysical measurements

Exploration is a crucial aspect of geothermal studies for renewable energy-based power generation. The Jaboi Volcano has been proposed for geothermal energy with a capacity of 80 Mwe. Remote sensing and geophysical data were integrated to support multi-criteria decision-making for geothermal resources exploration, such as groundwater, fractures, and faults related to the hydrothermal systems of the volcano. Several band ratios were used to clarify the hydrothermal minerals linked to the geothermal system, such as iron oxides, clay minerals, and Fe–Mg. In addition, rock and soil samples in the crater area were collected and analysed using the Fieldspec4 Hi-Res instrument. The result shows that the hydrothermal minerals are dominated by mixed clay with kaolinite, smectite, illite, and montmorillonite, confirmed by the USGS spectrum library. In the geophysical section, a vertical electrical sounding (VES) was conducted at 50 volcano stations. A 1D model generated using the least-squares algorithm shows the presence of local faults in the hydrothermal systems, such as Leumomate and Ceunohot faults, which function as the fluid transport pathways to the surface; the clay cap layer is also found at a depth of 200 m and the reservoir at 400 m characterised by the low resistivity. The presence of the faults is also validated by gravity observation with a high resolution of 200 m/px; the transformation and 3D density methods show the consistency of faults compared to the VES method. Integrating the geophysical and remote sensing data have provided the right decision on the presence of a shallow hydrothermal system in the Jaboi Volcano. © The Author(s) under exclusive licence to The Association of Korean Geoscience Societies 2025.