The delineation of low- to medium-temperature geothermal prospectivity zones in South Sulawesi, Indonesia, using GIS-based Analytical Hierarchy Process (AHP)

Geothermal potential of South Sulawesi is partly associated with old volcanic rocks aged ∼6.5–0.6 Ma but the distribution of prospective zones and geological controls of fluid circulation is insufficiently determined. Previous studies mostly depended on geological and geochemical observations with limited attention to geophysical datasets and a particular focus on magneto-telluric data which hindered reliable geothermal prospectivity mapping in old volcanic settings. Therefore, this study aimed to apply geospatial multi-criteria decision framework developed through Analytical Hierarchy Process (AHP) to delineate prospectivity zones for low- to medium-temperature geothermal resources. AHP weights were derived from multi-expert judgement to represent geological uncertainty and improve prospectivity classification reliability. The focus was on eight geoscientific parameters which included reservoir temperature, active manifestation type, volcanism, lineament density, lithology, gravity anomaly, hydrothermal alteration, and land surface temperature (LST). Prospectivity map reported that very low, low, and moderate classes covered 40.57%, 14.18%, and 26.77% while high and very high only had 18.05% and 0.43%, respectively. The high-to-very-high prospectivity zones recorded spatial correspondence with major structural lineaments, old volcanic units, active geothermal manifestations, thermal anomalies, hydrothermal alteration zones, and gravity anomaly patterns despite the limited coverage. The validation process conducted using receiver operating characteristic area under the curve (ROC-AUC) subsequently produced 86.8% which reflected robust predictive performance of the model. This study provided a practical framework for prioritizing prospectivity zones for further exploration and sustainable geothermal development in South Sulawesi.