The urban built environment offers a fundamental mean to reduce the risk posed by natural hazards, thereby preventing natural disasters. Disciplines like Architecture and Urban Planning become effective instruments to reinforce disaster risk governance and foster resilience. The following thesis investigates the relationship between natural disasters and built environment, focusing on the earthquake and tsunami hazard that threaten the Chilean coastal cities. It explores the coastal management strategies and the main existing mitigation systems for shore protection, both natural and engineered. Focusing on a case study, the city of Viña del Mar, it analyzes the reasons that led to the urban densification of the waterfront and the consequent risks that come from its exposure to inundation and tsunami hazard.