14. The Vulnerability of Human Population to Landslide Disaster: A Case Study of Sikkim Himalayas

The present study focuses on the Rani Khola River basin (RRB) in North East India’s state Sikkim. It is a tributary of the Teesta River and is naturally prone to landslide hazards. For the past few decades, RRB has witnessed a rapid rate of urbanization, resulting in increasing the vulnerability of the human population to hazards such as landslides, earthquakes, and floods. In the present study, assessment of the vulnerability of the human population to landslide has been carried out in two cases study sites, Gangtok Municipal Corporation (GMC) and Singtam within the RRB. Based on the framework by the Asian Disaster Preparedness Center (ADPC) and United Nations Disaster Risk Reduction (UNDRR), the element at risk data for human vulnerability is classified. This study aims at understanding the landslide hazard, vulnerability, and exposure to strengthen resilience and avoid future disaster risk. The Sendai Framework for Disaster Risk Reduction (SFDRR) 2015–2030 urges to engage in a series of actions at different levels (local, national, and global) to reduce the landslide susceptibility, risk, and losses in terms of human population and physical infrastructures. The Human vulnerability (V_h) or Social vulnerability of the study area was calculated using the Spatial Approach to Vulnerability Assessment (SAVE) model. The SAVE model initially searches for a pattern among a set of selected indicators followed by vulnerability estimation by defining the level of exposure (LE), sensitivity (S), and lack of resilience (LR). The final human vulnerability map is classified into five different classes, namely very low, low, medium, high, and very high. In Gangtok, the human vulnerability map is categorized into five classes namely very low, low, medium, high, and very high class which encompasses an area of 81.98% (15.89 km²), 3.82% (0.74 km²), 5.73% (1.11 km²), 5.33% (1.03 km²), and 3.14% (0.61 km²), respectively. In Singtam, the human vulnerability map is classified as very low (74.81%), low (1.92%), medium (9.81%), high (11.54%), and very high class (1. 92%). The result shows that in GMC areas such as Mahatma Gandhi (M.G.) Marg, Deorali, and Arithang, the human vulnerability is higher compared to other areas. The results of the present research can act as a firsthand tool to various researchers, planners, and policymakers for future preparedness and planning in the GMC and Singtam area.