Seismic vulnerability and risk assessment of Gangtok Region, India

Teja Malladi  | 2018


About 59% of India’s land is prone to moderate to severe earthquakes (M > 5) which makes it one of highest seismic risk prone areas in the world. Destructive earthquakes (M > 6.5), which are highly unpredictable, don’t occur frequently which makes people, local authorities ignore the importance of the earthquake resistant building design, disaster preparedness and post disaster management. The damage scenarios can act as the base for preparation of disaster management plans, taking mitigation measures and prepare population living in the high vulnerable areas. The research used HAZUS methodology is used for assessing vulnerability and damage caused by the 18th September 2011 earthquake at Gangtok (68 km from the epicentre) which is the capital city of state of Sikkim, a major hub for tourism and economy. The scale and the details of the results are directly based on the amount of information used in the execution of methodology. Parameters like magnitude and type of earthquake, distance from the epicentre to the study area, geology and local conditions of soil etc, and building characteristics for the vulnerability and damage assessment. Damages reported by the local authorities were used as the reference to validate the generated results and discuss the applicability of the method in Indian context. Based on the terrain conditions, the possible hazard zones and elements at risk, risk map was also generated. The results showed that concrete types of buildings were highly vulnerable and there is a high probability of damage to such buildings. These scenarios were matched with the reported damage. The research concludes that the HAZUS methodology can be used in Indian condition as HAZUS building types have some similarity with Indian building types.