Application of geospatial technologies for multi-hazard mapping and characterization of associated risk at local scale

Abstract

ABSTRACTIn this study multi-hazard risk assessment is carried out in Arithang ward, one of the major wards within Gangtok Municipal Corporation, with the objectives of (a) landslide and earthquake hazard mapping of Gangtok city with analytical hierarchy process (b) vulnerability mapping in Arithang ward and (c) semiquantitative and semiqualitative risk analysis. Landslide hazard zonation (LHZ) depicts that very high and high hazard zone occupies 6% and 17% of the Gangtok city whereas 60% and 18% of area falls under medium and low hazard category respectively. With respect to seismic hazard susceptibility 13% and 22% of area falls under very high and high category respectively. Semiquantitative risk analysis reveals that majority of the residential buildings are concentrated in low earthquake and landslide hazard zone followed by 39% and 35% within medium class. Only 0.6% and 7% of residential buildings are found in high earthquake and landslide hazard zones. Bamboo and wood made buildings are found to cluster within very high class of landslide hazard. About 61% of multistoried buildings are placed within low zone of LHZ. Risk analysis reveals that buildings at the eastern and western part of Arithang ward come under high risk with respect to earthquake and landslide.