APPLICATION OF HYPERSPECTRAL REMOTE SENSING AND QUANTITATIVE ANALYSIS TO DETERMINE HYDROTHERMAL ALTERATION ZONE IN ACTIVE GEOTHERMAL SYSTEM

• Main Author: Magfirah, Nurul
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/43835
• Institution: Institut Teknologi Bandung

The remote sensing mapping method using hyperspectral hyperion sensor images is effectively used in identifying alteration minerals in geothermal regions because it has a greater number of bands compared to other optical images. This study aimed at analyzing and mapping the alteration zones based on the distribution of alteration minerals in the Wayang Windu geothermal field. It also identifies the condition of the study area including rock type, weathering level, alteration type and alteration conditions at Wayang Windu geothermal field. Surface sampling in the form of soil and rock was carried out for laboratory analysis in the form of XRay Diffraction, X-Ray Fluoroscence and spectral compatibility analysis with spectroscopic reflectance data for validation of sensory data. Silica, kaolinite, sulfate, chlorite, zeolite and oxide mineral groups were identified which are the characteristics of advanced argillic and propylitic alterations. The mapping methods used in this study such as spectral angle mapper and linear spectral unmixing are able to map alteration zones in areas that are not vegetated to rarely vegetated. The use of volcanic alkali-silica (TAS) diagrams to classify rock types in the study area shows basaltic-andesitic to andesitic rock types, chemical index alteration (CIA) is a diagram to determine weathering levels by incorporating three oxide compounds namely Al2O3-MgO- (CaO) + Na2O + K2O) which shows high weathering area of research area, and ACF diagram, AKF is the determination of alteration minerals based on the appearance of minerals using the main elements namely ACF A (Al2O3-Na2O-K2O), C (CaO- [10/3] P2O5 ) and F (Fe2O3) while the AKF diagrams A (Al2O3-Na2O + K2O), K (K2O) and F (MgO + Fe2O3 + MnO) show intermediate argillic alteration types, the Intensity of Alteration (IA) equation shows alteration which occurs in the study area is classified as weak to strong altered.