Mount Pusuk Buhit is an active volcano around Lake Toba which has a height of 1980 meters above sea level. On Mount Pusuk Buhit there are geothermal manifestations in the form of hot water flows and fumaroles. What was carried out in this research was the identification of subsurface structures in geothermal manifestation areas using the GGMPlus satellite image gravity method. Based on the Sidikalang geological map sheet, in this study there are 5 types of rock formations, namely the Pusuk Buhit Formation (Qvpb), Kluet Formation (Puk), Kualu Formation (Mtks), Alluvium Formation (Qh) and Toba Tufa Formation (Qvt). Bouger anomaly values in this study ranged from -7.8 mGal to 6.0 mGal, low anomalies ranged from -7.8 mGal to -1.4 mGal. Moderate anomalies range from -1.0 mGal to 0.4 mGal. Meanwhile, the anomaly height in this study area ranges from 0.9 mGal to 6.0 mGal. The geothermal manifestation area on Mount Pusuk Buhit is located at a low anomaly. The depth of the residue map in this study is 520 meters while the regional depth is 1992 meters. From the results of this research, 22 faults were identified, namely 14 normal faults and 8 reverse faults. At this research location, the slicing results pass through 2 faults that are visible or detected on the surface based on the geological map of the research area. Slicing A passes through 1 fault while slicing B passes through 2 faults. In this research, to determine the existence of structures using the FHD (First Horizone Derivative) map, while to determine the type of structure found in the research area, use the SVD (Second Vertical Derivative) map. The results of slicing the FHD and SVD maps will then be processed in Microsoft Excel and an FHD and SVD graph will be created. To determine the existence of a curve structure, the FHD will show the maximum curve, while to determine the type of structure the SVD curve will pass through line 0. After obtaining the type of structure, the next process will be a 2D modeling was created. This 2D modeling will show a picture of the subsurface starting from the type of subsurface lithology found in the research area as well as the location of each previously identified fault. The second result of slicing in this research area passes through the geothermal manifestations of Mount Pusuk Buhit, Samosir Regency, North Sumatra. It is suspected that the appearance of manifestations on the surface is controlled by the existence of a structure directly beneath the manifestation.