Territorial index for seismic hazard in cities of developing countries

Abstract This study proposes the Territorial Seismic Hazard Index (ITAS), which integrates the interrelationship between biophysical and socioeconomic systems within a defined geographic area. The index provides information on the spatial distribution of urban zones requiring priority attention, based on the quantity, functionality, and type of exposed elements relative to seismic hazard characteristics. ITAS can be applied in territorial planning processes in developing countries. The index comprises two main indicators: Phenomenon Condition and Territorial Condition. The Phenomenon Condition reflects the constraints imposed by the biophysical environment (hazard) on territorial planning, while the Territorial Condition encompasses critical infrastructure and social dimensions, representing the social, economic, cultural, and political dynamics of the territory. Fuzzy logic was employed as the data-processing method to estimate ITAS. The method was applied to the city of Cali, Colombia, where results indicated that 163 neighborhoods had high index values, 108 medium values, and 62 low values. High values were mainly concentrated in the central and eastern sectors of the city, corresponding to areas susceptible to liquefaction and those with the highest ground acceleration, which also coincide with distinctive socioeconomic dynamics.