GIS-Based Landslide Hazard Zonation and Risk Studies Using MCDM

In India, landslides are the most frequently occurring disaster in the regions of the Himalayas and the Western Ghats. They are mainly triggered either by rainfall or earthquake or the combination of both, causing severe damage to human life and infrastructure. This study presents a comprehensive use of the multi-criteria decision-making (MCDM) method in landslide risk assessment for the Tehri area in the state of Uttarakhand, India. The Tehri area is situated in the Lesser Himalaya of Garhwal hills which lies in zone IV of seismic zoning map of India. Because of the large-scale slope instability in the area, it has received the special attention of the researchers. In the recent past,—many landslide hazards and risk zonation is carried out for different regions in the Uttarakhand state. However, limited work is done considering temporal factors such as seismic ground shaking, rainfall, and seismic amplification at surface level. The DEM data is used to produce topographic characteristics such as slope, aspect, and relative relief. DEM data is also used for the detailed drainage analysis which includes topographic wetness index (TWI), stream power index (SPI), drainage buffer, and reservoir buffer. Seismic hazard analysis is performed using the deterministic methodology to estimate the peak horizontal acceleration. The amplification factor is calculated using the non-linear site amplification method. In this study, the analytical hierarchy process (AHP) is used to evaluate the landslide hazard index which is used to generate landslide hazard zonation (LHZ) map. Further, the landslide vulnerability assessment is done for the study area. The vulnerability map of the study area is derived in terms of landuse/landcover (LULC) using remote sensing data of Landsat 8 which can provide useful information that helps people to understand the risk of living in an area.