Advancing level-2 seismic vulnerability assessment: a scalable framework for large building stocks

Seismic risk metrics in India are increasingly outdated due to the nation’s current seismic zonation being based on limited historical earthquake data. As risk is a function of hazard (H), vulnerability (V), and exposure (E), these changes demand improved assessment frameworks. This study introduces an advanced Level 2 seismic vulnerability assessment Framework—the Extended Earthquake Disaster Risk Index (EEDRI)—designed for large-scale building stock evaluation. The framework refines qualitative risk assessment by integrating a probabilistic hazard factor, derived from seismic zone classification, soil type, and spectral amplification, into fragility function development. It estimates exceedance probabilities across four defined damage states (slight, moderate, severe, and collapse) under incremental hazard levels. Validation is carried out by comparing EEDRI-based fragility curves with those generated via the Capacity Spectrum Method, a Level 4 quantitative approach. The proposed methodology bridges qualitative and quantitative techniques, offering a scalable and resource-efficient decision support framework that is equally applicable to both code-based hazard assessments and site-specific evaluations, thereby enhancing disaster mitigation in large and diverse building inventories.