Detecting distribution pattern of latent hydrothermally altered zones by geobotanic remote sensing

Koike, Katsuaki*; Uchiyama, Kyosuke*; Koide, Kaoru

Joho Chishitsu, 23(2), p.68 - 69, 2012/06

Hydrothermally-altered zones frequently collapse in intense rain and are intimately related to genesis of heavy metal mineralization. Therefore it is very important to investigate their distributions from the viewpoints of disaster prevention and mineral resource exploration. This study developed a new vegetation index (VIGS) for detecting abnormalities of vegetation induced by differences in soil chemistry and soil moisture related to hydrothermally-altered zones. The VIGS includes the green and mid-infrared bands, which are highly sensitive to vegetation water stress. To validate its availability, this VI was applied in a landslide prone area (Hachimantai) and a gold deposit area (Hishikari Mine) using Landsat TM data. As a result, it was found that the VIGS is very useful to detect abnormalities of vegetation related with hydrothermally-altered zones because abnormalities of vegetation coincide with landslides and hydrothermally-altered zones associated with gold mineralization.