فهرست مطالب امیر پیشوا

The pervasiveness of the concept of vulnerability in various dimensions has led to the emergence of the theory of vulnerability in the spatial sciences. According to the theory of vulnerability, in any given space, there is a coefficient of vulnerability, while the levels and amplitude of safety are not evenly distributed on the surface of that space. Residential use is one of the most important and main uses in the urban land use system, and safety management and attention to its defense requirements are very important due to the high population density in large cities. The present study is in the field of assessing the vulnerability of residential uses against external threats with a passive urban defense approach in District 10 of Tehran, which was conducted in the form of spatial studies and by implementing an analytical model in three steps. First, the principles and requirements of passive defense were identified and classified into three groups of structural, demographic and spatial parameters, and using the questionnaire and expert survey tools, the priorities of passive defense principles in relation to residential spaces were determined. Then, based on the network analysis process, the weight of each criterion was determined and the weight of the ANP model was applied to the spatial layers of the region in ArcGIS software. The results of the model showed that in terms of structural indicators, more than 78% of residential units in the region are in the group of structures with high vulnerability and in terms of demographic indicators, in 88% of residential units in case of external threats, the level of vulnerability is high. In terms of spatial indicators, more than 92% of residential spaces are adjacent to several incompatible uses and have the highest vulnerability. In general, the results of overlapping layers showed that more than 86% of residential units in the area are located in vulnerable zones and the vulnerability of residential units in these zones is very high.

Due to the uncontrolled abstraction of groundwater resources in the last half century, the water level of groundwater aquifers in most plains of Iran has decreased sharply. Sharp drop in groundwater levels is the main cause of land subsidence in Iran. Land subsidence has the potential to cause a major human catastrophe, and if it happens, it will expose agricultural lands, urban fabric, vital arteries, and many other environmental aspects to extreme vulnerability. This study evaluated the vulnerability of urban fabric in District 18 of Tehran regarding the influence of land subsidence. The spatial study was carried out by implementing an analytical model in three steps. In the first step, the indicators of vulnerability of urban tissue affected by land subsidence were identified and classifiedbased based on three criteria of physical and demographic, access and proximity to high risk centers. In the second step, using a questionnaire and expert’s ideas, the priorities of urban tissue vulnerability in relation to land subsidence were identified and based on the network analysis process, the weight of each criterion was determined. In the third step, the weight obtained from the ANP model was applied to the spatial layers of the region in ArcGIS software. The results of model implementation showed that a high percentage of District 18 have features such as worn texture, buildings with low structural strength, very low building quality, high population and construction density and are prone to high vulnerability. Moreover, Zone 1 with 96%, Zone 2 with 88.5%, Zone 3 with 90.4%, Zone 4 with 85%, and Zone 5 with 92.3% have high vulnerability. About 90% of the total buildings constructed in District 18 of Tehran are affected by land subsidence in a highly vulnerable area.