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Abstract:
Earthquake has played a major role in current landslide scenario of Uttarkashi since past few decades. Moreover Uttarkashi lies in the seismically active part of India based on Indian seismic zonation map (zone IV). It has become necessary to determine the earthquake induced landslide hazard with increasing magnitude and area of earthquake. The objective of this study is to prepare an earthquake-induced landslide hazard map using Analytical Hierarchal Process (AHP) and GIS for Uttarkashi, Uttarakhand. Over 65 Earthquake epicenters (ranging from a magnitude of 3.5 to 6.8) along with landslide points in and around the study area have been considered. Further, 12 factors are taken into consideration including tectonic framework, earthquake magnitude distribution, distance to epicenter, fault/focal mechanism, topography along with other landslide factors. Shake maps are used for the peak ground acceleration (PGA) and peak ground velocity (PGV) analysis. The consistency ratio (CR) determined for AHP is 0.075(<0.1), which indicates an acceptable preference matrix for the associated factors. The weights assigned to the above factors are validated using Relative Frequency Ratio method. Earthquake induced landslide susceptibility map is prepared and the zones are classified accordingly. The validation of these maps was accomplished by the area under the curve (AUC) method.
