Application of the Gravity Method in Indonesian Geothermal Exploration (2015–2025): A Systematic Literature Review on Methodological Evolution and Geodynamic Characterization

Abstract

Indonesia possesses vast geothermal energy potential yet faces significant subsurface geological complexities. The gravity method is a vital geophysical tool for mapping host-rock density variations during preliminary exploration. This systematic literature review (SLR) synthesizes the methodological evolution, data processing advances, and multi-method integration of gravity applications in Indonesian geothermal exploration over 2015-2025, based on rigorous screening of 239 articles yielding 50 representative studies. The review reveals a paradigm shift from logistically constrained terrestrial surveys toward high-resolution spaceborne gravity constellations (GGMPlus, WGM 2012) for regional reconnaissance. Data processing has advanced from qualitative visual tracing to standardized gradient-based operators: First Horizontal Derivatives (FHD), Second Vertical Derivatives (SVD), Tilt Derivatives (TDR), and Horizontal Gradients (HG) alongside 3D volumetric numerical inversions that effectively mitigate potential field non-uniqueness. Integrating gravity-derived density structures with Magnetotelluric (MT/CSAMT) resistivity models and remote sensing parameters (Land Surface Temperature and Fault Fracture Density) provides the most robust framework for bounding clay caps and fluid-flow pathways. Despite adaptability across volcanic-hosted and non-volcanic fractured-basement settings, a critical spatial disparity persists, with publications heavily clustered in Western Indonesia. This review underscores the urgency of high-resolution acquisition across Eastern Indonesian frontiers and 4D microgravity monitoring to support Indonesia’s Net Zero Emissions target by 2060.