Operational airborne hyperspectral remote sensing for global geothermal exploration

Airborne hyperspectral technology' has progressed to global implementation possibilities for geothermal exploration and assessment. This work describes the unique capabilities of hyperspectral imagers as they pertain to the mapping and characterization of geothermal regions including both geological and biological material mapping. Many of the geological processes, phenomena and products (such as alteration) associated with regions of high geothermal gradients can be imaged, measured, geospatially placed and identified accurately and precisely over large, contiguous areas in virtually any region of the globe by aircraft-mounted imaging spectrometers such as HyMap. For example traditional drilling and field surveys provide extensive mineralogical data at depth and over very small areas. Such activities are considered mandatory in any geothermal exploration program. However hyperspectral remote sensing has the capability to accurately map continuous surface mineralogy over very large areas at small spatial scales (eg. siliceous sinter, travertine or alunite distribution). While resource satellites such as Landsat and ASTER do provide global coverage of basic geology at relatively low spatial resolutions (15-30 m) and low spectral resolutions (40-700 nm), directed high spatial and spectral resolution airborne surveys with HyMap (3-5 m spatial and 13-17 nm spectral) afford incomparable material map generation capabilities. These include not only the specific mineral identification maps discussed above, but also mineral chemistry measurements, proxy temperature estimates and associated geobotanical measurements and distribution maps (that include not only types of vegetation but also relative physiological state).