A New Method for Assessing the Seismic Risk of Urban Fabrics in Iran

In order to reduce the seismic risk in urban fabrics effectively, it is necessary to make a comprehensive assessment of vulnerability and seismic hazards in different parts of the urban area. This could provide essential information for city managers and decision makers for better understanding of risk mitigation priorities. Since in most cities of Iran, the required data are usually unavailable or inadequate, estimation of absolute risk is not possible. In this paper, a simple and comprehensive methodology is introduced to estimate the relative seismic risk among urban zones instead of absolute risk. For this purpose, parameters with significant contribution to seismicrisk are selected and classified into physical, human life and socio-economic categories. The seismic risk associated to indicators of each category is estimated according to the vulnerability and relevant hazard factors. It can conceptually reduce uncertainties in combination of earthquake hazard and vulnerability through definition of separate hazard factors. The effect of response capacity and recovery capability are also considered in estimation of total risk; however, relevant methodology and parameters of this item are now under study. Finally, the model is applied to estimate the seismic risk of Tehran at district level, and results are compared to other works. Considering the impacts of all presented indicators, results of the proposed model show that district 15 has the highest rank of seismic risk in Tehran Metropolitan area.