Usage of ASTER Level 3A Stereo Data in Landslide Inventory Mapping: Visual Determination Versus Fieldwork

摘要

Studies related to natural hazards have become an extremely important issue among the geoscientists for the last few decades. Particularly after the mid 1980s, developments in computer technology, GIS (Geographic Information Systems), and RS (Remote Sensing) have provided rapid and detailed analysis of different natural hazards such as landslides, earthquakes, floods, and so on, in larger areas. Combined with field observations, these analyses may provide important knowledge in assessing natural hazards. Landslides are one of the most destructive parts in natural hazards. Similar to many countries in the world, Turkey, a landslide suffering country, faces this problem. In Turkey, landslides are of great importance among the natural hazards, and the Western Black Sea region is one of the major landslide prone areas. For this reason, in this study, we selected an area in the Western Black Sea region, in order to investigate the usage of ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) satellite imagery in preparing landslide inventory maps. For this purpose, two- and-three dimensional visual image interpretation was performed at different scales varying from 1:15,000 to 1:50,000. Particularly VNIR (Visible Near Infrared) bands of the ASTER images were used in the analyses. Field studies were also carried out in the study area to map landslides and to compare different landslide inventories. Based on the analyses, it was revealed that the best method to prepare landslide inventory maps by visual interpretation was found as stereoscopic (three dimensional) image analysis at 1:15,000 scale. ASTER Level 3A data were used to create stereo images, RGB (433) in other words ASTER 3N (Nadir) and 3B (Backward) bands can be used to produce stereo images. The smallest mapped landslide was determined as 58,885 m~2, covering approximately 262 pixels. As a result of the assessments, it is considered that ASTER satellite imagery can successfully be used in regional and medium scale landslide inventory studies.