Integrating seismic and tsunami data for multi-hazard consequence functions: toward scalable loss scenarios

Multi-hazard risk scenarios are gaining increasing attention in disaster risk modeling, especially in regions where primary events—such as earthquakes—can trigger cascading hazards like tsunamis, landslides, or coastal flooding. A major challenge in this context lies in the limited availability of empirical damage and loss data for secondary hazards, particularly tsunamis. This work proposes a framework for estimating tsunami-related economic losses by transferring knowledge from the seismic domain, where rich datasets and calibrated cost functions are already available. By correlating tsunami and seismic damage states through engineering-based criteria, the method enables the derivation of repair cost ratios for typical reinforced concrete buildings, even in the absence of observed tsunami damage. A key refinement is the introduction of uncertainty in the extent of ground-story infill wall damage, allowing a more realistic quantification of non-structural losses. The methodology is applied to a representative RC building configuration reflecting the construction practices of high-risk coastal areas in southern Italy. A parametric analysis explores how building height and damage extent influence the repair cost ratio, providing insight into the vulnerability of low-rise structures. The proposed approach supports scalable loss modeling in regions characterized by data leverage and contributes to more informed planning in multi-hazard contexts