Structural map of Sulawesi derives from gravity data and its implications for geothermal systems

¹ Department of Geological Engineering, Gadjah Mada University, Yogyakarta 55281, Indonesia
² Department of Physics, Gadjah Mada University, Yogyakarta 55281, Indonesia
³ Department of Mining Engineering, Universitas Muslim Indonesia, Makassar 90231, Indonesia

^* Corresponding author: ws@ugm.ac.id

Abstract

Gravity satellites are one of the alternatives to conducting preliminary surveys because the cost of exploring a large area using conventional gravity methods is very expensive and takes a lot of time. Therefore, this study on Sulawesi Island uses a gravity satellite to identify fault contact boundaries. The methodology in this study consists of several steps, starting with a literature study, data collection through ICGEM, and then processing and analysis by compiling the gravity anomaly with the Sulawesi regional geological structure map, further interpreted using the classification of rock density variations from a geological perspective. The regional gravity anomaly values for Sulawesi Island and its surroundings range from -270.9 mgal to 320.8 mgal, averaging 78.99 mgal. High anomalies are estimated to be between 180 mgal and 360 mgal, dominated by land with a lithology predominance of igneous rocks, while low anomaly areas are identified in the Batui thrust subduction zone. This study concludes that the convergence of high and low gravity anomalies characterizes the fault contact boundary in the study area. This has implications for the geothermal system on Sulawesi Island, which has a significant impact as a medium for the release of hot fluids from the subsurface.