Comparative tsunami vulnerability assessment of an urban area: An analysis of Setúbal city, Portugal

Portugal's historical vulnerability to natural hazards has been well documented and the need exists to create a local assessment framework at the municipal scale. Therefore, the objectives of this paper are to implement and compare two methodologies for assessing the vulnerability of buildings in urban area of Setúbal city. In this study, the area inundated by the tsunami was obtained from other authors who carried out the tsunami numerical simulation of the 1755 Lisbon Tsunami in Setúbal. The methodologies used were the PTVA - 3 model and Model B, which incorporate several parameters that influence vulnerability. These parameters were defined on the basis of post-tsunami field surveys carried out by other authors. They were classified according to their influence on the capacity to protect or cause damage and incorporated into a GIS environment by applying multi-criteria analysis and calculating vulnerability indexes. The results show the presence of 481 potentially affected buildings. Approximately 90% (using both methodologies) were classified as very low or low vulnerability. Within these categories, it is important to note that two buildings associated with the emergency response service are potentially affected, in addition to five buildings important to the normal functioning of society. The buildings that were classified as high vulnerability are storage facilities used by fishermen and an annex to the port of Setúbal. In addition, the PTVA - 3 model highlights the number of floors in the buildings. The methods can be developed to include physical, social and economic indicators.