spatial organizing and distribution of gas stations following urban passive defense approach (case study: gas stations of mashhad metropolis)

passive defense is a set of civilian efforts performed to enhance deterrence, reduce vulnerability, sustain essential activities, promote national stability, and facilitate crisis management against military threats of an enemy. since in battles, sensitive and critical areas of cities are of paramount importance,it is clear that in military agressions, a large part of threats are focused on cities and their urban facilities and equipment, especially fuel centers. as a result, consideration of passive defense while planning cities has a significant role in reducing the vulnerability of cities and their urban elements as well as facilitating the urban crisis management. it also provides the citizens resistance threshold under possible enemy invasion and natural malicious agents. hence, this article reviews and analyzes the current situation of gas distribution centers and evaluates their positioning across the city of mashhad with regard to passive defense approach. however, as far as there is no clear- cut criteria for organizing fuel centers with passive defense approach, the delphi method is used to select the desired criteria in which on the basis of the final comments  of the experts,  four critera- performance, access, hazards and security election and spatial organization of the fuel tanks and petrol stations- are analyzed using ahp model and gis spatial analyzes. accordingly, it can be said that the assessment of the current status of the urban fuel stations in mashhad indicates that no area of the city enjoys all  measures of passive defense (performance, availability, security, and  risks). likewise, the results indicate that the distribution of these centers in the city are mostly consistent with the factor of access. taking into account all the criteria, it is the ​​north west of mashhad which has the highest utility than other areas. it is followed by the east of mashhad and ​​the northeast and the middle east of the city, respectively. accordingly, it could be stated that ignoring an efficient design for  determining the optimum location of the site construction with a passive defense approach results in an inappropriate and naive spatial distribution of the stations leading to an increased security and environmental risks of the city.