S E S ‘ 2 0 0 5 Scientific Conference “SPACE, ECOLOGY, SAFETY” with International Participation 10–13 June 2005, Varna, Bulgaria SOME APPLICATIONS OF THE REMOTE SENSING IN GEOLOGY BY USING OF ASTER IMAGES Kalin Rouskov 1 , Kamen Popov 1 , Stanislav Stoykov 1 , Ysushi Yamaguchi 2 1 -University of Mining and Geology "St. Ivan Rilski", Sofia 1700, Bulgaria 2 - Department of Earth and Planetary Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan rouskov@mgu.bg, kpopov@mgu.bg, sstoykov@mgu.bg, yasushi@nagoya-u.jp keywords: aster, remote sensing, geology Abstract. ASTER (The Advanced Spaceborne Thermal Emission and Reflectance Radiometer) is a research facility instrument, launched on NASA’s Terra satellite in December 1999. It is sensor systems with a unique combination of wide spectral coverage and high spatial resolution. The ASTER instrument has three spectral bands in the visible and near-infrared (VNIR), six bands in the short-wave-infrared (SWIR), and five bands in the thermal infrared (TIR) regions respectively. The ASTER also has a back- looking VNIR telescope, thus, stereoscopic images are acquired at 15-m resolution. ASTER was built to serve different application areas as vegetation and ecosystem dynamics, hazard monitoring, geology and soils studies, land surface climatology, hydrology, and land cover change. The main aim of this article is to illustrate the ASTER’s ability to provide an information for alteration minerals, which are valuable for mineral prospecting and exploration activities. Several band ratio composite images, highlighting the possible distributions of iron oxides and clay minerals in the area of Assarel and Medet ore deposits are given. The iron and alteration minerals spreading form two stripes, related to the faulting zones which control the development of mineral deposits and numerous ore occurrences in the studied area. Introduction In its broadest sense remote sensing methods includes aerial and satellite observations of the surfaces and the atmospheres of the Earth and the other planets in our solar system also. Some of the main purposes of the remote sensing are making and updating topographic maps, weather forecasting, gathering military intelligence, etc. The focus of this article concerns some geological applications of the remote sensing for the Earth’s resources investigations. The Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) is a research facility instrument, launched on NASA’s Terra spacecraft in December 1999. The ASTER has 14 spectral bands in the visible and near-infrared (VNIR), the short-wave-infrared (SWIR), and in the thermal infrared (TIR) regions (ASTER Ref. Guide, 2003). Usage of the satellite imagery has many benefits than other sources of geographic data as the aerial photography and the paper maps. For large areas satellite images are often less expensive than other sources of information. Some basic application fields of the remote sensing are listed below: • Geology – prospecting and exploration of the natural resources, structural 167