Analyzing spatial distribution of Landslide Vulnerability assessment using Geoinformatics and Geotechnical Modeling; A case study of district Abbottabad

Abstract

This research is the first step towards determining the landslide susceptibility with the aim of providing solutions for disaster risk management and emergency response by the help of the use of Geographical information systems and remote sensing datasets and techniques in the rugged mountainous terrain of district Abbottabad. The objective of the research was first of all assessment of landslide hazard susceptibility using GeoInformatics (GIS & RS) methods and datasets followed by Geotechnical field survey at different landslide inventory locations for validation of results. Eleven triggering factors were prepared in a GIS environment for development of landslide susceptibility maps namely slope, stream power index, aspect, topographic wetness index, plan curvature, distance to road network, proximity to fault lines, precipitation, distance to stream network, Landuse/Landcover and lithology using digital elevation model (DEM), Geological maps and Tropical rainfall measuring mission (TRMM) etc. Analytical Hierarchy process (AHP) is used for the purpose of allocating weights to these causative factors and their sub-classes based on expert opinion. Finally, weighted overlay analysis was applied in order to combine all the weighted layers to produce a final landslide susceptibility map of district Abbottabad, dividing the research area into low, moderate and high zones. The results indicated that high susceptible zones covered an area of 25% while moderate and low zones covered 54% and 21% respectively. Slope was the most influencing factor followed by lithology and precipitation while aspect, distance from streams and topographic wetness index were the least contributing factors. Landslide Susceptibility Score (LSS) technique on landslide inventory points for validation of the susceptibility map. Landslide Geomorphological mapping was also performed in order to identify different landslide features and see their effect such as head, scarp and toe. The results showed good agreement between geospatial and geotechnical approaches once the landslide spatial locations were overlaid on the susceptibility map. The susceptibility map can be utilized as an effective source for governmental organizations, policy makers, engineers and planners containing valuable information so that emphasis in future can be laid on the high as well as moderate susceptible zones for any sort of developmental works, prepare service centers, rescue routes and shelters in disaster management planning and emergency response.