GRAVITY PROCESSING AND INTERPRETATION OF WAE SANO GEOTHERMAL FIELD

• Main Author: Ababil Akram, Muhamad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/51843
• Institution: Institut Teknologi Bandung

Western part of Flores Island has run into rapid progress in tourism industry for past few years. Electricity demand is increasing due to this matter. In order to meet demands, exploration of geothermal energy is conducted in Wae Sano. Wae Sano geothermal field is expected to have potention of 26 Mwe. The purpose of this study was to investigate the geothermal system of Wae Sano geothermal field based on the interpretation of gravity data. This research was conducted by analyzing the gravity method that starts from processing the gravity measurement data conducted by PSDMBP in 2015 to obtain a complete Bouguer anomaly. The complete Bouguer anomaly range is 60 - 116 mGal. Then anomalous separation is performed to obtain residual Bouguer anomalies by using the moving average method which produces anomalies of -20-14 mGal. To assist in forwarding the 2.5D modeling, a qualitative analysis was performed with the First Horizontal Derivative method which has an anomaly range of -0.06 to 0.04 mGal and the Second Vertical Derivative method which has an anomaly range of -11 - 8 mGal. The results of the modelling with a base density of 2.65 gr / cm3 show that there is an intrusion of diorite (?? = +0,15 gr/cm3) , dasit - rhyolite lava and pyroclastic product around the crater of Sano Nggoang (?? = -0,25 – 0,47 gr/cm3) which breaks through the Poco Dedeng volcanic unit (?? = +0,00 gr/cm3). The bedrock in this area is interpreted as a tertiary age sedimentary rock unit (?? = +0,05 gr/cm3). There is also a fault structure pattern in the study area in accordance with previous geological research. There is a fault structure pattern in the study area in accordance with previous geological research. Based on the results, the upflow zone is estimated to be in the Wae Sano hot spring manifestation area. While the outflow zone is estimated to be in the area of manifestation of Namparmancing warm water and Bobok warm water.