Case Study 1: ITALIAN CASE STUDY

For the Italian case study, the impacts of low probability, high consequence seismic hazard scenarios and the landslide cascading hazard effects were evaluated for a road network located in the province of Bologna in northern Italy.

The vulnerability of the selected road network was characterised according to the seismic vulnerability of the network bridges and tunnels, as well as the vulnerability of road sections to earthquake-triggered landslides. To do so, fragility functions were assigned to individual network elements based on their structural characteristics. The cascading earthquake-triggered landslide effects were assessed according to determined values of landslide yield acceleration for the region.

The consequences of the extreme hazard scenarios were evaluated in terms of the network repair costs (i.e. the direct consequences), as well as the travel disruption to network users (i.e. the indirect consequences). To determine the potential transport disruption due to the hazard scenarios, traffic analyses were conducted using NEXTA traffic simulation software.

The impacts were determined by comparing simulated post-hazard traffic scenarios to the network operations under ‘normal’ conditions. A quantitative risk analysis was performed for the network to determine the potential losses due to the considered scenarios and the results demonstrated that the potential direct consequences are substantial for the selected case study area in terms of repair costs. For the indirect consequences, the results demonstrated that the losses were substantial at national scale in terms of traffic disruption and economic losses.