An integrated assessment of seismic hazard exposure and its societal impact in Seven Sister States of North Eastern Region of India for sustainable disaster mitigation planning

Abstract

Abstract The Seven Sister States of the North Eastern Region of India, located on the complex seismotectonic belt, is characterized by high seismicity. A comprehensive seismic hazard exposure assessment is carried out by quantifying hazard using a probabilistic approach, vulnerability by factor analysis, and exposure mapping by integrating seismic hazard and vulnerability. Peak ground acceleration (PGA) values at bedrock are calculated with the help of ground motion prediction equations (GMPE) for 10% probability of exceedance in 50 years (475 years) and 100 years (950 years), and 2% probability of exceedance in 50 years (2475 years). The resulting spatial distribution of the PGA values considering return periods of 475, 950, and 2475 years are presented through seismic hazard maps. The social vulnerability analysis indicates that 21 districts covering 91.43% area of the state of Assam and the entire state of Tripura are under high vulnerability. With the help of spatial cluster analysis, it is found that 17.14% of the study area are having an average social vulnerability index (SVI) score of 0.329 and therefore can be considered as hotspots. Through seismic hazard analysis, it is observed that more than 50% of the area of North East India is under moderate to very high exposure class. The seismic hazard maps developed can help in disaster mitigation planning and execution leading to sustainable development goals and targets.