ndonesia has one of the largest tropical peatland areas in the world. In Sumatra Island, peatland spreads over 11 regions, and it is mainly found in Riau (60.1%) and South Sumatera (19.6%) Provinces. This study investigates the subsurface of tropical peatland in Ogan Komering Ilir Regency, South Sumatra Province. Data were recorded using Electrical Resistivity Tomography (ERT) method based on the sub-surface images of tropical peatland. This study was conducted based on the dipole-dipole configuration with 72 channels spread. This paper also studies the physical properties (thickness and electrical resistivity) of peatland and its substrate using ERT. In this study, the ERT section and the geological map identified Alluvium (Qs), Kasai Formation, and the Basement. The result shows the ERT is applicable for imaging the thickness of tropical peatland and other geological features (Aquifer, geological structures, and stratigraphy). The electrical resistivity of peat varies from 20-ohm meter to 120-ohm meter, and the thickness of peat varies from 2–5 meters. In some ERT sections, the basement was identified from 130 meters to 170 meters beneath the surface. The aquifer sweet spots were located from ERT Sections combined with the hydrogeological map. The aquifer was identified in Kasai Formation. The thickness of the aquifer layer is 2–20 meter. These physical properties may support peatland conservation (forest fire mitigation) and geotechnical analysis purposes.
