Tsunami risk mitigation: the role of evacuation routes, preparedness and urban planning

Abstract The southwestern Portuguese coast, particularly the Algarve region, is at significant risk of an earthquake exceeding magnitude 8, which could generate a destructive tsunami. Coastal areas such as Quarteira and Vilamoura in the Loulé municipality are especially vulnerable due to their dense population of permanent residents and seasonal tourists, compounded by the long distances required to reach safety zones. Despite the known seismic and tsunami hazards, there have been limited studies that develop tailored mitigation strategies specific to tsunami evacuation. This study contributes to the tsunami science by evaluating potential building damages due to shaking and tsunami impact and providing decision support for evacuation strategies. Using Geographic Information Systems (GIS), tsunami scenarios are modeled based on historical seismic events, such as the 1755 Lisbon earthquake, to identify high-risk coastal zones and optimize evacuation routes, considering local topography and population density. Additionally, wave propagation and arrival times are analyzed to ensure timely access to population escape and to mitigate damage to critical infrastructures. Our findings contribute to the developing a comprehensive tsunami risk mitigation strategy for the Loulé municipality, focusing on prevention, public safety, and emergency preparedness. This research supports land use planning, disaster risk reduction, and emergency planning decisions while also advancing the understanding of urban risk by addressing hazards, exposure, and vulnerability in coastal areas. Key objectives of this study include acquiring and implementing historical tsunami data, assessing recommending evaluating the region´s vulnerability, and recommendations for good practices and mitigation measures. The study emphasizes the importance of raising public awareness, enhancing governance, and strengthening capacity to effectively reduce disaster risks.