A novel dynamic disaster risk assessment of urban built environments: An application to flood and earthquake

This study presents a dynamic disaster risk assessment methodology for urban built environments, integrating flood and earthquake scenarios with spatiotemporal patterns of population exposure and vulnerability. Using an open-space-centred and multi-layer single-risk approach, the framework combines hazard intensity, physical vulnerability and user behaviour to identify urban “hot-spots” under different emergency conditions.

These are some of the key findings from the case study emerge:

• While overall criticality levels are comparable for earthquakes and floods, their spatial distributions diverge significantly. Flood risk concentrates in open spaces near the river, where hazard intensity and user exposure converge.
• The distinction provided by point (a) emphasises the importance of hazard-specific mapping to support targeted mitigation. The combination of strategies oriented towards flood risk awareness (including alerts and evacuation activation) and mitigation (e.g., structural solutions like flood barriers) would be beneficial for the open spaces placed along the river.
• Differences in occupancy scenarios imply differences in risk levels for both the assessed disasters. Nevertheless, impacts also depend on the specific single risk.