Using River Profile to Identify Instable Zones in Parts of Tang-e-5 Area, Zagros Fold Belt (ZFB): An Application of Remote Sensing & GIS Techniques

要旨

The Dez River is one of the main rivers which cross the Zagros Fold Belt in the south west of Iran. Due to presence of natural hazards like landslides in the Zagros Fold belt the Dez River is selected for reorganizing of the unstable zones in the Tang-e-5 and Shahbazan areas using geographical information system (GIS) techniques. The area is one of the most critical hazardous areas in the Zagros Fold belt. Remotely sensed data of Landsat ETM+, FCC 4-3-2 dated 9-Nov-2002 and field observation data were used in the study area. The Dez river profile was digitally drawn on digital elevation model (DEM) of the study area to evaluate the unstable zones of landslides prone using GIS techniques. In this research a new theme and method is given to facilitate the unstable zones interpreted by analyst using graded and steepened profile extracted in GIS environment using Rivertools software. It is observed that if the river channel is lowered due to erosion, then the hill slope angle is steepened and rates of creep will increase. This results the hill slope may become unstable zone and chance of disaster due to landslides. The study shows that area has been subjected not only to the tectonic activities but also the rugged topography and landscape influenced erosion. This study reveals that changes in the slope angle are related to changes in the altitudinal differences between the interfluves and river channels. However, river profile is useful as one of the interpretational keys for identification of natural hazards in an area.