[M-GI34] 情報地球惑星科学と大量データ処理情報

[MGI34-11] ハイパースペクトル衛星画像に基づく植生ストレス指数分布を用いた高植生被覆地域からの地熱流体パスの検出

*久保 大樹¹、権守 宏明¹、ヘリアワン モハメドヌル²、小池 克明¹ (1.京都大学大学院工学研究科、2.バンドン工科大学)

キーワード：地熱資源探査、ハイペリオン、インドネシア、リモートセンシング、スペクトル分離

Detection of geothermal fluids paths including steam and gas from a geothermal reservoir is a major target of geothermal prospecting. Remote sensing analysis is one of the low-cost and effective methods to detect fractures distribution that have a function as fluid flow paths. However, vegetation cover is an obstacle for prospecting when the geothermal potential field are located in tropical mountainous areas. In this study, we extracted geothermal manifestations from highly vegetated areas using the linear spectral unmixing (LSU) method and a vegetation stress index. Hede et al. (2015) applied a vegetation stress index calculated from multispectral data, and we improved the index, termed as Vegetation Index considering Blue shift and Shortwave infrared (VIBS), using hyperspectral data which has a higher wavelength resolution. The Wayang Windu Geothermal Field (WWGF) situated in West Java, Indonesia was selected as a study site. Vegetation-covered zones were extracted from a hyperspectral image, obtained by Hyperion using the application of LSU. The spatial distribution of VIBS was clarified over the whole vegetation-covered area. The high-stress zones by VIBS were mainly overlapped with the location of geothermal manifestations in WWGF. In addition, lineament distribution was estimated from DEMNAS, the digital elevation model provided by the geospatial information agency of Indonesia. The high permeable zones were estimated from the lineament distribution and the result of the radon gas survey (Heriawan et al., 2020). The corresponding high-stress with the estimated high permeable zones suggested the presence of permeable fractures that act as the ascent paths of geothermal fluid flows.