Imaging the alteration minerals and Hydrothermal Systems using ERT and Landsat 9 to support Clean Energy at Jaboi Volcano

Jaboi volcano is one of Indonesia’s geothermal energy resources with a potential of 50 MWe. Various studies are needed to accelerate the geothermal industry. Apart from reservoirs and clay caps, several other factors control geothermal areas, including faults, fractures, and local geology, which varies from one volcano to another. We use Landsat 9 data to assess the presence of altered hydrothermal minerals and temperature changes as indicators of geothermal potential. In contrast, electrical resistivity tomography (ERT) is used to visualize the subsurface hydrothermal system. The band comparison and Principal Component Analysis (PCA 1–3) of Landsat 9 show clear contrasts related to hydrothermal minerals, such as clay and iron oxides, which are consistent with their manifestations. Meanwhile, surface temperatures from 2000 to 2025 show highly consistent thermal anomalies around hot spring areas, indicating potential geothermal zones. The 2D inversion calculated by the least-squares model shows several conductive anomalies associated with subsurface magmatic activity, including on the west side, with rho values (log 0.5–1.5 m) in response to manifestations along the Ceunohot fault and observed on the volcano’s surface. On the east side, the resistive anomaly is observed at a depth of 15-25 m, corresponding to hard rock material in the subsurface (> log 2.5 m), which inhibits fluid flow to the surface. The integration of these two datasets provides a comprehensive assessment of the potential and activity of the Jaboi hydrothermal system, which is essential for determining injection and production wells and for planning protection of geothermal springs.