Measuring the Vulnerability of the Urban Fabric in the Face of Land Subsidence (Case Study: District 17 of Tehran)

Abstract

Urban vulnerability is the probability of damage to cities and urban infrastructures against natural and unnatural events. In this regard, in the last half century, land subsidence has involved many countries as a potential risk for urban, industrial and agricultural areas. With the occurrence of land subsidence, the physical and structural characteristics of the structures built in the city are changed and show different behavior. For this reason, it is important to consider the effect of land subsidence on the urban fabric in which there are exposed and buried structures. The involvement of the 17th district of Tehran with the issue of land subsidence was the initial idea of the current research. Currently, the maximum land subsidence rate in this area is 25 cm per year. The present research has been carried out in the form of spatial studies and by implementing the analytical model in four steps. The results of the model implementation showed that the urban fabric of the 17th district is prone to high vulnerability due to features such as high population and building density, the presence of worn-out fabric, buildings with low structural strength and very low construction quality of buildings. In total, about 657 hectares (80 percent) of the built-up lands in the 17th district of Tehran are under the influence of land subsidence.