ALTERATION STUDY USING LANDSAT 8 OLI/TIRS IMAGE OF DENSELY VEGETATED AREAS OF THE WAYANG WINDU GEOTHERMAL FIELD, PANGALENGAN, WEST JAVA

• Main Author: EDWIN SALAMBA (NIM : 12113006), KRISTIAN
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/22847
• Institution: Institut Teknologi Bandung

Remote sensing is the method usually used for conducting geothermal reconnaissance surveys by mapping the surface alteration anomalies, which can be captured by a satellite’s multispectral image sensor. This study aimed to analyze the characteristics of the surface alteration zones in the Wayang Windu geothermal field, Pangalengan, West Java, using remote sensing method from multispectral images from Landsat 8 OLI/TIRS and validated by groundtruth data from field surveys. The Wayang Windu geothermal field, with an elevation of 1500–2600 masl, is located in Pangalengan and lies in a quartery volcanic arc. The rock types include andesite, basalt, tuff, breccia, and pumice. The faults in the study area was directed to northwest-southeast and northeast-southwest. The research process included a literature review, field surveys, laboratory using spectral reflectance analysis to determine the reflectance from soil samples and the mineral composition in the field, X-Ray Diffraction to determine the mineral composition, and X-Ray Fluorescence to determine the abundance of elements. The imagery used in this study is the Landsat 8 OLI/TIRS with an acquisition date of September 10, 2013; the multispectral images were evaluated using Directed Principal Component analyses. The combination of field surveys and remote sensing enhanced the spatial data. The surface alteration zones in the Wayang Windu geothermal field are correlated with joints and faults. Based on their mineral composition, the surface alteration zones were identified as an advanced argillic zone with the occurrence of secondary minerals such as cristobalite and halloysite, and a propylitic zone with the occurrence of secondary minerals such as epidote and chlorite.