Identification of Fault Structure in the Vicinity of Bukik Gadang Hot Spring Mount Talang Subdistrict Using Geomagnetic Method

Geological structures in the Bukit Gadang geothermal area have been identified using geomagnetic method to determine type of fault. Data was measured a magnetometer with dimensions 1200 m × consisting 144 points at 12 tracks, and spacing between 100 m. Magnetic anomaly data performed diurnal IGRF (International Geomagnetic Reference Field) corrections. Furthermore, reduced poles continuous upwards processes were carried out remove noise separate local regional anomalies. The magnetic field ​​in study ranges from -1771.8 nT 1089.9 nT, dominated by negative values, indicating presence heat sources influence demagnetization subsurface rocks. 2D modeling results show that two primary rocks dominate area; pyroclastic flow units andesite lava rock, which come Jantan Batino volcanic formations. caprock rock layer upper depth 850 meters. reservoir low susceptibility values ​​was below layer. 3D normal fault 300-800 meters or border formation formation. line leads southeast-northwest (N160°E). faults obtained models are suspected be outflow fluid form manifestation hot spring Bukik Gadang.