MODELING OF GEOTHERMAL SYSTEM BASED ON GRAVITY DATA OF CUBADAK GEOTHERMAL FIELD, DUO KOTO, PASAMAN, WEST SUMATERA

• Main Author: Frenty Br Tarigan, Mey
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/51160
• Institution: Institut Teknologi Bandung

Geothermal energy needs to be developed in Indonesia because geothermal energy is one of the environmentally friendly energies and is a form of renewable energy. The Cubadak geothermal field, Duo Koto, Pasaman, West Sumatra is one of the areas that has a volcanic-tectonic geothermal system that emerged due to the Sumatra fault. Therefore it is necessary to conduct research with the right method to understand geothermal activity and subsurface geological conditions. One of the methods used is the gravity method. The purpose of this research is to determine the geothermal system model that develops in the Cubadak geothermal field. In this study, data were used in the form of complete Bouguer anomaly and topographic values. Furthermore, the data is being plotted and contoured so that it becomes a digital map of Complete Bouguer Anomaly (CBA). The separation of regional and residual Bouguer anomalies was carried out using a moving average filter where the window width value was obtained by performing 1D spectral analysis. In the Bouguer anomaly map, regional and residual anomalies show a high anomaly in the northwest part of the study area. Through 2.5D modeling results, the presence of high anomalies is estimated as Granodiorite intrusion which has a density contrast of +0.23 gr / cc. The existence of Granodiorite intrusion is thought to be a source of heat for the manifestation of Cubadak and Sawah Mudik hot springs. The reservoir in the Cubadak area is a pyroclastic flow unit which has a thickness of 1.2 km. The layer that becomes the caprock is a unit of lake sediment.