Simple Method to Use Spectral Remote Sensing Data in Geothermal Exploration

Abstract

Several methods that apply remote sensing data to geothermal exploration were compared in Chile. Recommendations based on these tests include use of immediately available, low-cost or free ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) data, application of classification processing in easily-used, free Multispec software, performance of processing, interpretation, and field checks by a general geothermal geologist, and field mapping of alteration. Data types in the test were limited to low cost data including air photos, Landsat, and ASTER data with the intent to escalate to more expensive, higher spectral resolution data depending on selection of a methodology and demonstration of efficacy. Escalation was not expected to be cost-effective based on this test. Data were obtained, processed, and applied to exploration in three field areas, Puchuldiza, Alitar, and Tolhuaca. Processing methods applied standard mineral industry advanced processing, expert custom processing using a variety of approaches, collection of field spectra and visual inspection of samples, expert interpretation, and simple classification. Results helped locate areas to field check for alteration. Comparisons of data types, methods, and results as applied to Tolhuaca, Chile are reported here.