Hot springs are among the most common geothermal surface manifestations, typically emerging through fractures formed by tectonic processes. The subsurface structures associated with the Grao Sakti hot spring manifestation in Jangkat, Merangin Regency, were identified using GGMplus gravity data by analyzing rock density contrasts through cross-sectional interpretations of the First Horizontal Derivative and Second Vertical Derivative of the gravity anomaly data. The Complete Bouguer Anomaly map reveals several gravity anomalies ranging from 73.8 to 174.6 mGal, which are interpreted as the Masurai, Hulunilu, and Sumbing volcanic complexes, Dikit Fault Segment has promoted the development of a fault-bend basin within the study area and the Barisan Mountain Range. Structural interpretation based on the FHD and SVD maps indicates the gravity derivative results indicate that the Grao Sakti manifestation is associated with a subsurface structure interpreted as a normal fault. This interpretation is consistent with regional geological evidence, and previous studies conducted along the Grao Sakti hot spring profile that normal fault is interpreted to have developed as a consequence of the formation under a transtensional tectonic regime movement of the Dikit Fault Segment, a major segment of the Sumatran Fault System, which trends in a northwest–southeast direction.
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