Towards a unified seismic- flood- hazard model for risk assessment of roadway networks in Greece

Abstract

Roadway networks, playing a vital role in the economic prosperity of modern societies. Recent hazardous events in Greece, for instance, the 2021 Thessaly earthquake and floods and the heavy 2019 rainfall in Crete, have demonstrated the vulnerability of roadway networks to natural hazards, resulting in severe physical damage and important economic and societal losses. Severe damage on bridges and tunnels of roadway networks is commonly related to the effects of multiple hazards that may act independently during their life. However, the literature on risk assessment of the above elements is commonly focused on the effects of one hazard, disregarding the potential interaction effects of diverse hazards in a multi-hazard environment. In this context, there is an increasing need for reasonable and effective evaluation of the multi-hazard risk of transportation infrastructure. Research project INFRARES aspires to bridge this gap by gaining further insight into the risk assessment of bridges and tunnels of transportation networks in Greece, when subjected to separated and subsequent hazards, with particular emphasis being placed on seismic and flood hazards. The present paper briefly presents a unified methodology to homogenize the single seismic and flood hazard scenarios and develop appropriate single- and multi-hazard maps for Greece to be used in risk assessment of roadway networks. Seismic hazard data, referring to rock site conditions, developed within the SHARE research project (www.share-eu.org), is initially selected and is properly amplified to account for site effects, by employing a simplified Vs,30 model originating from morphology and topography data of each region in Greece. The seismic hazard is estimated for a return period of 475 years. Flood hazard zones are derived for whole Greece using newly developed data from the Joint Research Center of the European Commission (https://data.jrc.ec.europa.eu/dataset) for the 100-years return period scenario. Using the above input, both single hazard and multiple hazard models are developed and provided in terms of maps in GIS format. The model developed within this study is expected to be a valuable contribution towards the generation of a uniform multiple hazard model for the risk assessment of critical elements of transportation infrastructure in a multi-hazard environment.