Earthquake and tsunami multi-hazard natech risk assessment for petrochemical storage facilities

Industrial accidents can occur triggered by natural hazard events, where phenomena such as earthquakes, tsunamis or hurricanes, can lead to structural damage of storage facilities and/or piping. That may then cause the release of hazardous substances, initiating a chain of cascading effects, potentially involving fire, blasts, or toxic pollution. The term NaTech has been introduced to describe such natural-hazard- triggered technological accidents. This article presents a possible multi-hazard NaTech risk assessment for process industry plants accounting for earthquakes and tsunamis. A hypothetical waterfront liquefied petroleum gas tank farm situated at a coastal Italian site is considered, as a representative module of an oil refinery. The risk assessment uses steel storage tank fragility functions for earthquake ground shaking and tsunami waves, which depend on each tank’s filling level of the tanks. These are integrated with seismic shaking and tsunami inundation hazard curves for the site considered, to provide the annual rate of tank failure, where failure is defined as structural damage able to cause release of contents.