A pilot survey for mapping the fault structure around the Geuredong volcano by using high-resolution global gravity

Global gravity has been used successfully for studying the tectonic mechanism around the world, and the global data can be accessed freely with different resolutions. Global Gravity Model Plus (GGM+) has the highest resolution of 200 m/px. The high-resolution data apply to regional studies and utilize more local areas, such as studying fault structures in volcanic areas, the main access point for seeping fluids to the surface. We used GGM + data to assess the geological structure and faults of the Geuredong volcano located in the central of Aceh, Indonesia. The volcanic mountain is estimated to have an energy of 55 Mwe. We validated the GGM + data with TOPEX/Poseidon data with the lower resolution of 1.83 km/px and showed the same response. The GGM + data with higher resolution describe the regional fault system in Geuredong volcano. Moreover, the global gravity data were also validated by ground survey data measured over ​​20 km 2 with a distance between 250 and 300 m, the validation results between GGM + and ground gravity survey show the same response between the two-gravity data with an RMS error of 15.07%. The residual anomaly from GGM + can map several local and regional faults in the Geuredong volcano area. The horizontal transformation specifies fractures and strike-slip faults, the critical mechanisms for the formation of surface manifestations. The 3D modeling with Occam’s algorithm and Singular Value Decomposition (SVD) shows the fault is at a 1–2 km depth indicated by a low density of 2.4 g/cm 3 . The cross section results from the inversion model also show the same response as the Geuredong geothermal conceptual model. Based on data processing, the GGM + data can study the fault structure in volcanic areas, especially in high terrain conditions such as tropical countries with inaccessible mobility and developing countries that are financially limited to gravity ground surveys.