A geographic approach of the global vulnerability in urban area: case of Manizales, Colombian Andes

Abstract

Manizales, intermediate city in the Andes of Colombia, is exposed to three major natural phenomena: frequent landslides, earthquakes and, to a lesser extent, floods, all sometimes causing catastrophic disasters. The city was established in 1849 on a high ridge between two rivers (interfluve). This narrow plateau has steep slopes that have been occupied since the early 1940's. Since then, a lack of sites approved for construction has not stopped urban expansion, which continues affecting unstable areas, even when geotechnic works have been realized in those areas. The people most frequently affected by hazards live in `sub-integrated' districts (shantytowns) situated in the more sloping lands. Nevertheless, recent disasters have occurred in the new developments where the middle classes live, showing the role of the urban growth in the creation of a growth of vulnerability and risk. The investigation consists of perfecting a method of analysis of the relationships between the urban process and the installation of such a situation. Using statistical tools (PCA and Bertin matrices), we estimated the global vulnerability of the city and represented it, at the scale of the neighbourhood level, in an integrated map.