Assessment of urban seismic social vulnerability based on game theory combination and TOPSIS model: a case study of Changchun City

Earthquakes, as one of the common natural phenomena in China, can directly lead to the collapse of buildings and trigger secondary effects such as landslides and tsunamis, often resulting in significant property losses and casualties. Therefore, conducting seismic risk assessments for regions holds great practical significance. Current disaster research typically requires a comprehensive consideration of the probabilities of disaster-causing factors, the instability of disaster-prone environments, and the vulnerability of disaster-bearing entities. In low seismic risk areas, studying the vulnerability of these entities is particularly important. However, most current research on social vulnerability (SV) in the context of earthquake disasters employs a single weighting method, which is largely constrained by data types and makes it challenging to fully reflect the characteristics of social vulnerability. To address this issue, this study focuses on Changchun City and constructs a comprehensive index system consisting of 12 indicators from the perspectives of exposure, sensitivity, and coping capacity. The TOPSIS model and game theory-based combined weighting method have been utilized to calculate the Social Vulnerability Index (SoVI). In this framework, subjective weights were determined using the G2 method, while objective weights were computed by integrating the CRITIC method and the entropy weighting method, thus forming a more scientifically reasonable weight distribution approach. The results of various weighting combinations demonstrate that the model can effectively express social vulnerability and further elucidate the influence of each indicator on regional vulnerability. The findings indicate that Chaoyang District and Yushu City exhibit high levels of social vulnerability. This paper conducts an in-depth analysis of the reasons behind this phenomenon and proposes corresponding policy recommendations, providing specific guidance for mitigating social vulnerability in these areas. This research is fundamentally significant for promoting the implementation of earthquake disaster prevention and reduction planning in Changchun City and fostering sustainable regional development.