LANDSLIDE HAZARD ZONATION IN THE MOUNTAIN BRIDGE WILDERNESS AREA USING GIS-BASED MODELING

In mountainous regions, landslides are among the most expensive and dangerous natural hazards, often resulting in property damage and even human casualties. The Mountain Bridge Wilderness Area located along the Blue Ridge and Piedmont provinces in North and South Carolina experiences infrequent but unpredictable mass wasting events, sometimes resulting in closure of the primary roads and trails and permanent change to the landscape. Though the North Carolina Geologic Survey has made major strides in developing a landslide hazard index map for most part of Western North Carolina, no such study has been conducted for the state of South Carolina. The main objective of this study is to develop a landslide susceptibility index for the study area using GIS based heuristic modeling approach. The model divides the study area into zones of hazard based on the intrinsic and extrinsic variables such as land cover, slope angle and aspect, geology, structures, and precipitation. The final landslide susceptibility map was produced by using a weighted overlay operation in GIS. The results of the study reveal that 8.7% of the study area falls within the highest hazard zone, while 88.7% of the study area is in a medium hazard zone, indicating that much of the area is likely to experience slope failure if the right conditions converge. The landslide susceptibility map can be used by local officials to implement regulations that prevent unstable slopes from being developed.