Assessment of Subsurface Structures for Geothermal Exploration in Curup, Indonesia, Using Satellite-Derived Gravity Anomalies
Puja Kasmailen Putri, Marzuki Marzuki, and Ahmad Fauzi Pohan

Andalas University

Abstract

The Suban Curup area in Rejang Lebong, Bengkulu Province, Indonesia, is a tourism destination and lies along the subduction zone of the western Sumatra magmatic arc, near the Ketaun fault segment and the active Kaba Volcano. These geological features suggest significant geothermal energy potential, although comprehensive mapping efforts remain limited. This study utilizes satellite-derived gravity data from the GGMPlus 2013 model, comprising 1,937 data points acquired from Curtin University (Perth) and TU Munich (TUM). The Bouguer anomaly was calculated using a refined field correction approach based on full-scale topographic gravity data from the SRTM2 model. Regional and residual anomalies were separated through two-dimensional radial spectral analysis and continuous upward continuation techniques. The results indicate that the average thickness of the sedimentary layer in the study area exceeds 100 meters, suggesting the presence of shallow subsurface structures. These findings provide a foundation for subsequent 3D modelling of density contrasts, taking into account the regional geological context of Curup. The analysis reveals patterns of intrusive igneous rocks with high-density contrast, the Merapi magma chamber with low-density anomalies, and fault segment boundaries marked by abrupt density changes. The outcomes of this study are expected to inform and support local government initiatives in developing geothermal power infrastructure in the region.

Keywords: Geothermal, gravity, Inversion modeling, Ketaun segment, Kaba volcano

Topic: Earth Physics and Space Science