Landslide Susceptibility Zoning Using New Synthetic Method in the GIS Environment

Landslides are one of the most natural hazards in hilly regions with great human and economic losses in the worldwide. Iran is always exposed to landslide susceptibility because of climatic and physiographic conditions. The purpose of this research is landslide susceptibility mapping using AHP-Density area model in GIS environment in the part of Haraz Watershed.

Landslide inventory map was created using field surveys, and then conditioning factors were prepared. Using AHP model and Expert Choice software, weight of each factor was calculated. Weight of classes for each factor was calculated using the density area model in the GIS environment. Finally, weight of classes and weight of factors was multiplied. Weighted map was integrated in GIS environment and the final zoning map created.

Results indicated that lithology, distance from road, slope angle, distance from drainage network, land use, elevation, and slope aspect are the main landslide controlling factors in the area. Results showed that slope of 15-50 percent, north and west facing, altitude of 1,500–2,100 m, residential and mixing orchard and agriculture area types of land use, distance of 500 meter from road and 400 meter from drainage network, Shemshak formation and fluvial terraces are very susceptible to landslide.

In general, study area is very susceptible to landslide occurrence and landslide susceptibility mapping is very essential in this region. The resultant map would be useful for general land use planning.