Remote Sensing Application in Evaluating the Southern Leyte Geothermal Project, Southern Leyte, Philippines

Abstract

Remote Sensing (RS) approach was applied to refine the existing geological and hydrological models of the Southern Leyte Geothermal Project (SLGP). Landsat thematic mapper and radar imageries were processed mainly for geological and structural interpretations. The spectral classification of altered grounds and/or thermal springs was extracted from the Landsat TM imagery using the Normalized Difference Vegetation Index (NDVI) and the Principal Component Analysis (PCA) methods.

This study reveals the spatial relationship between faults, lineaments, stratigraphic contacts and hydrothermal manifestations in the project area. The northeast and east-northeast structures dissect the Cantodoc-Tamar volcanic edifice and control the distribution of most hydrothermal manifestations (i.e., Mahalo-Mainit thermal area to the east and Tabunan thermal area to the west). Mount Cabalian harbors predominant NW structures that are believed to channel hydrothermal fluids at deeper levels of the reservoir (i.e., Hugpa kaipohan). This study indicates the existence of more than one geothermal system in SLGP which include (1) Cabalian, (2) Cantodoc, and (3) Tamar system. Geophysical (e.g., resistivity and gravity anomalies), geochemical, and thermoluminescence data are consistent with this geological evaluation.