An integrated framework for pluvial flood and tsunami hazard assessment at coastal sites: application to cultural heritage

Abstract This study develops an integrated comparative assessment framework that couples high-resolution pluvial flood rain-on-grid (RoG) modeling with a geographic information system-based tsunami hazard assessment for coastal sites. The approach enables return-period-dependent flood hazard and damage potential assessments using physically based, computationally efficient metrics. The framework bridges the pluvial flood and tsunami communities by linking two-dimensional shallow-water RoG simulations for localized pluvial hazards (500–1000 year return periods) with NEAM Tsunami Hazard Model 2018-based probabilistic tsunami scenarios for multiple return periods. High-resolution hydraulic modeling generates detailed pluvial inundation maps, while tsunami scenarios provide spatial fields of water depth, flow velocity, and momentum flux. Comparative results show that pluvial floods dominate hazard at moderate return periods, producing 0–1 m inundation and sub‐1 m s −1 velocities along drainage pathways, whereas tsunami events control at longer return periods (2475+ years) with greater depths and velocities over broader coastal zones. Momentum flux analysis is used to classify structural damage potential for both hazards and indicates that extreme tsunami scenarios can cause severe damage to limestone masonry. The integrated framework provides transparent physical parameters that support cross-disciplinary collaboration and guide risk management: moderate-frequency strategies should prioritize drainage infrastructure and pluvial flood management, while rare-event coastal resilience planning must explicitly account for catastrophic tsunami scenarios and coastal asset protection.