Towards an integrated framework for the risk assessment of coastal structures exposed to earthquake and tsunami hazards

Abstract

The spatial distribution of the world population is uneven, with a density of about 40% living in coastal regions. The trend is expected to continue in both demographic indicators and urban development rate, being many coastal cities in seismic- and tsunami-prone regions and built through informal and unplanned settlements, exposing their population and assets to such hazards. Recent tectonic-triggered events raised awareness of the cascading earthquake and tsunami threat and highlighted the paucity of structural design criteria considering the cumulative effects of both. By being exposed to the ground-motion, the structures’ resistance may decrease and become residual/non-existent to support the incoming tsunami, implying an underestimation of the risk.Risk management can benefit from reinforcing the ties between natural hazards and engineering practitioners, linking science and industry, and promoting dialogue between risk analysts and policy-makers. Motivated by the expansion plans of an internationally-sized deep-water port located in a tsunami-prone region, a reflection on the work needed to perform a multi-risk assessment and the challenges yet to overcome is introduced to emphasize the challenge of combining safety requirements with financial and ecologic concerns. A conceptual interdisciplinary-based methodology is proposed to support uncertainty-aware, systematic and informed decisions.

Keywords

• Cascading earthquake and tsunami
• Multi-hazard
• Structural vulnerability to earthquake and derivative tsunami
• Performance-based engineering to cascading ground motion and tsunami