An investigation on effective dimensions and indicators in measuring resilience of historic-commercial urban fabrics against earthquake hazards with a special view to traditional Bazaars

INTRODUCTION
To determine the status of resilience, a wide range of subjects should be considered and studied. For this purpose, at first, the presented resilience models should be evaluated. Amongst the existing resilience models, in Baseline Resilience Index Conditions (BRIC) model introduced by Cutter et al. in 2010 [1], community resilience is categorized into five dimensions: social, economic, institutional, infrastructural, and community capital. In Climate Disaster Resilience Index (CDRI) model introduced by Shaw et al. in 2009 [6], the five main dimensions of resilience are introduced in as social, economic, institutional, physical, and natural. MCEER report [5] introduced a resilience model named PEOPLES, which evaluates resilience of communities in seven main dimensions of population and demographics, environmental/ecosystem, organized governmental services, physical infrastructures, lifestyle and community competence, economic development, and social/cultural capital. In 2015, Khazaei et al. in 2015 [2] in the Disaster Resilience Index model (DRI), introduced the effective indicators of resilience in five dimensions of legal and institutional, awareness and capacity building,  critical, critical services, infrastructure resiliency, development planning regulation, and risk mitigation using Disaster Resilience Index model (DRI). Ostad Taghizadeh Ostadtaghizadeh and Ardalan [4] have also studied the effective indicators in disaster resilience of communities in Tehran in six dimensions: institutional, economic, cultural, social, physical, and environmental. Thus, the main and common fields of resilience are physical, economic, social, and institutional dimensions; which were previously introduced by Bruneau in 2003 [7].
On the other hand, the consequences of destructive earthquakes such as Bam (Iran, 2003), Sumatra (Indonesia, 2004), Tohoku (Japan, 2011), and many other cases have depicted that the occurrence of natural disasters usually affects valuable historical fabrics, including traditional Bazaars. However, the existing models introduced above cannot be utilized to assess the resilience in these historic and cultural urban fabrics. Therefore, due to the special characteristics of traditional Bazaars, it is necessary to develop appropriate models based on specific characteristics of these urban fabrics. In such models, different characteristics of bazaars such as type, age, and importance of buildings from a physical point of view, population density in different hours and delinquency rate from a social perspective, ownership, wealth density, and valuable goods from an economical point of view, and social capital from cultural perspective should be formulated. Besides, historic commercial parameters should be also considered.
MATERIAL AND METHOD
In this paper, a set of indicators were selected to evaluate the resilience of traditional bazaars. Some of these parameters were chosen from the previous general resilience models and other related indicators. After eliminating duplicated or overlapping items, 136 indicators were selected and classified into five categories. Then a questionnaire was prepared based on this list and was distributed amongst the relevant specialists to evaluate the importance of each indicator. Based on the results, those indicators that the level of agreement for them was 50% or more were chosen for entering into the final list of indicators. At this stage, by removing 50 indicators from 136 indicators, 86 items remained. By merging a number of them according to their similarities, the final number of indicators was reduced to 50 in five dimensions: physical, economic, social, and institutional, historical-cultural aspects. To determine the weight of dimensions, indicators, and sub-indicators, a questionnaire-based survey was conducted. For this purpose, 45 experts in relevant fields were selected. Then, based on the results and by using Analytical Hierarchy Process (AHP), the weight of indicators and sub-indicators were determined, accordingly.
WEIGHTS OF SELECTED INDICATORS
The social aspects of resilience in Bazaar were introduced as the most important dimension from the perspective of the first group of specialists (university professors) and the physical dimension was selected by the second group (professional experts). The physical and economic dimensions were also chosen as the most important aspects based on the opinion of the third group (graduate students in the relevant fields). By calculating the final weights, it was observed that the social, physical, and economic dimensions are the most important, respectively.
In the physical dimension, almost all three groups selected the vulnerability of buildings as the most important index. Therefore, the final weight of 62.2% has been calculated for the vulnerability of the buildings index. Similarly, in the economic dimension, the economic value of the business with a weight of 71.1% has the highest degree of importance among the three economic indicators. Unlike the previous two dimensions, in the institutional dimension, this agreement was not observed among the three groups. Therefore, the strength and diversity of organizational structures index with a final weight of 36.8% has been identified as the most effective index among the four institutional indicators. Among the social indicators, the preparedness level index and the population structure index with the final weights of 37.6% and 31.1% were selected as the most important indices in the model, respectively. In the cultural-historic dimension, the index of cultural values with a final weight of 47.2% was the most effective.
Figure 1 shows the final weights of the most effective indices of the resilience in historic-commercial urban fabrics. Prioritization of sub-indices based on their weights shows that the most effective factor in the resilience of these fabrics against earthquakes is the building use indicator with a weight of 11.3%. Indicator of building use is a criterion that shows the type of activity of each unit, including commercial (textiles, bags and shoes, carpets, jewelry, paint and glue, cosmetics, food, home, and industrial equipment and ....), warehouse, school, religious, and residential use. Then sub-indicators such as the economic value of property and goods, adaptability and dynamics for post-earthquake recovery, improvement and retrofitting of buildings in each zone, previous experiences and preparedness, belief and sensitivity to earthquake risk and willingness to pay to earthquake risk reduction, per capita income level compared to the city average, training on risk reduction, the vulnerability of road network have the highest degree of importance in the resilience model. The total weight of the nine indices mentioned above is equal to 0.532, which is more than 50% of the total weight coefficients of the 50 sub-indices introduced in the model.
 
Fig. 1. Ranking of first 13 resilience sub-indicators based on the final weights
 CONCLUSION
This paper presents new indicators for the assessment of the resilience in traditional bazaars, as important historic – commercial urban fabrics. It was depicted that many indicators and sub-indicators should be considered for the resilience assessment of these fabrics; some of them may not be considered in ordinary urban fabrics. The degree of importance of each dimension, indicator, and sub-indicator from the perspective of three different groups of experts was somewhat different, which is mostly due to their attitude to the concept of resilience. Therefore, a combination of different opinions was considered to determine the impact factor and weight of each item. The conducted survey also depicted that the social dimension has the highest weight in the resilience of traditional Bazaars. Therefore, investment in improving social conditions may have the best efficiency in promoting the resilience of these fabrics to natural disasters such as earthquakes. Accordingly, the priorities for interventions in these fabrics can be determined. This may reveal also how to allocate funds to promote resilience in these fabrics, appropriately.
The results of this study also showed that focusing solely on improving specific dimensions of resilience or merely focusing on improving physical indicators (such as reducing the vulnerability of buildings) is not necessarily the best option for improving the resilience of traditional Bazaars. Furthermore, it should be considered that the rehabilitation of historical urban fabrics often faces many complexities due to the historical and cultural value of those fabrics that cannot be changed, easily.