Increasing tsunami risk through intensive urban densification in metropolitan areas: A longitudinal analysis in Viña del Mar, Chile

This article addresses the topic of tsunami risk in the context of early warning and response. We examine how zoning schemes can promote or mitigate intensive densification processes in locations exposed to natural hazards, and how this can lead to increased risk in urban areas. We introduce a tsunami risk index for the Población Vergara neighborhood in the city of Viña del Mar, Chile, through a longitudinal study that combines population-related census data (1992–2017) and zoning provisions, tsunami flood modeling and evacuation modeling into a GIS-based model. The purpose of the study is to examine how recent substantial changes in population density have led to increased tsunami risk conditions in one of the most sought-after locations in the Greater Valparaíso Metropolitan Area and how these conditions are related to current and previous zoning schemes. The results show an overall significant increase in tsunami risk conditions over the course of the examined census interval. This work can contribute to a better understanding of how residential densification (fostered by real estate-driven development and permissive zoning schemes) can exacerbate tsunami risk in other coastal cities in Latin America and the world.