GRAVITY PROCESSING AND INTERPRETATION ON KINTAMANI GEOTERMAL FIELD

• Main Author: Chumaida Haryani, Arsy
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/51321
• Institution: Institut Teknologi Bandung

Indonesia is a country with the largest geothermal potential in the world, with estimated potential of 27 GWe. There are 252 geothermal locations in Indonesia are spread following the path of volcanic formation from Sumatra, Java, Bali, Nusa Tenggara, Sulawesi to Maluku. Therefore, as an effort to understand geothermal activity and subsurface geological conditions, geophysical exploration in the form of gravity method. The area that is the object of research is the Kintamani area. The research aims to determine the model of the geothermal system that develops in the Kintamani geothermal field. In this study, Complete Bouguer Anomaly (CBA) and topographic data on the Kintamani geothermal field were used. Then the anomaly is separated using two different methods, namely the moving average method and the second order polynomial method. The results of the two methods are compared and one that is correlated with the geological conditions of the study area is chosen to be used in the modeling process. The Bouguer anomaly map shows a low anomaly in the middle of the study area and a high anomaly in the eastern part of the study area. The results of the second order polynomial method anomaly showed a high anomaly value in the eastern area of the study area which was estimated to be due to the Lava Abang unit, so this method was considered to have a correlation with the geology of the study area. Through the 2.5D modeling results, the low anomaly in the middle of the study area is estimated as the presence of andesite-basaltic magma which has a density contrast of -0.72 g / cc. The presence of andesite-basaltic magma is thought to be a heat source. Ignimbrit Caldera Batur 2 is thought to be the reservoir layer. Andesitic Lava Batur 3 is thought to be the caprock.