رضا قاسمی

There is no comprehensive model for quantitative calculation of resiliency. To this end, using documentation studies and expert opinions, the conceptual model of the resiliency of cities against earthquakes were extracted. It is considered that resiliency has social, economics, technical, physical, institutional, and security dimensions. The 6th municipal district of Tehran was considered as case study. Using the proposed index and considering three seismic scenarios, the effectiveness of technical-physical and socio-economics strategies in improving the resiliency of the studied district were compared. In order to better compare strategies, the costs of implementing strategies and the time span of their implementation are also estimated. The weights of social, economic, technical, physical, institutional, and security dimensions were 0.198, 0.153, 0.136, 0.202, 0.151 and 0.159, respectively. The value of the resiliency index is 0.458, 0.454 and 0.456 in North-Tehran fault, Ray fault the floating scenario, respectively. At the best case, the S3 strategy improved the RI by about 33% in all the three assumed seismic scenarios. The T3 strategy for the case of the North Tehran fault scenario improved RI by 31% and in other two seismic scenarios, the improvement was about 28%. S3 strategy is the best strategy for increasing the overall resiliency index considering the cost of implementation as decision measure and the weakest strategy is T1 in this regard. Nevertheless, in terms of the time span as decision measure T1 is the optimal strategy. In the short run, T1 and, in the long run, S2 are the best strategies.

The study of cities resilience against earthquakes is one of the requirements for planning to reduce damages, fatalities, and financial losses due to earthquakes. Resilience has many definitions and there is no a comprehensive model for calculating; Therefore, this paper aims to provide a quantitative indicator for resilience. First, effective indicators and dimensions in resilience of cities against earthquake were extracted by using library studies and obtaining experts opinions. Then, the weight of each dimension and indicator was determined based on expert judgment and paired comparison method and finally, the resilience index was introduced. Findings: In this paper, while introducing a summary of disaster definitions and resilience, the dimensions and indices obtained from previous studies and expert opinions were introduced. These dimensions and indicators represent the factors influencing urban resilience against earthquakes. Accordingly, the urban fabric dimension, which represents the city structure, plays a major role in the resilience of the city against earthquakes, after which the security dimension is the most important factor in resilience of the city. Regarding the indexes, in the physical dimension, the "building height / passage width ratio" index has the most impact on the resilience of the earthquake against the earthquake in experts’ opinions. The number of building floors has little impact and does not matter much about vulnerability in case of using proper structure, sufficient space, and easy access to the passages. The results show that the introduced index for different cities, as well as various strategies for retrofitting and increasing resilience can be calculated and make it possible to choose an optimal strategy for increasing resilience. It is also possible for planners and decision makers to observe the effects of different sections on the resilience of the city or region under study.