Assessing the threats and vulnerability of the New City of Andisheh with a passive defense approach

Describing and evaluating the threats and vulnerability (weaknesses) of cities is a framework for analyzing and managing risks related to possible attacks against key infrastructures. In fact, the identification of threats in the field of passive defense, i.e. intentional man-made threats and possible damages, plays an important role in prevention and preparation for facing and dealing with the negative effects of man-made threats and natural hazards to urban areas, which by knowing the dimensions of risk and damages It is possible to define and develop the level and type of measures to deal with these damages up to the scale of neighborhoods and urban residents. In this research, vulnerability and threat assessment studies are carried out in the new city of Andisheh with a passive defense approach for reasons such as high population density, especially in the city center, proximity to Tehran, and the existence of a large workforce that is mainly employed in Tehran. The increasing and uneven development due to the saturation of Karaj and Tehran, the favorable climate that attracts the overflowing population of Tehran, the centrality between Tehran, Qazvin and Central provinces, the presence of many military and industrial centers around the city, etc.

Materials:

The current research method is descriptive-analytical with a survey perspective (Delphi technique). In terms of nature, considering that the current research is not only about mere description and matters such as recognition and analysis, evaluation and formulation of principles are considered together, therefore it is also included in the category of analytical research. The method of collecting information includes questionnaires, observations and interviews, and the statistical sample of the research consisted of 30 experts and specialists in the field of city, security and safety from organizations and universities related to the subject of the research.  Methods In this research, the methods of assessing the threats and vulnerability of the new city of Andisheh are as follows:Threat Assessment Method In order to evaluate the threats of intentional man-made research, the combination of AHP (Analysis Hierarchy) and FEMA (Emergency Management Agency) techniques have been used to analyze information. After distributing the threat assessment questionnaire and completing it by the community of research experts, the arithmetic mean of the opinions of the community of experts was scored based on the Likert scale, which is common to the FEMA technique. In order for the scores provided in this way to evaluate the identified threats of the research to be effective; AHP method has been used for weighting the threat evaluation indicators.

Vulnerability estimation is surrounded by ambiguities and uncertainties; because calculating the amount of past vulnerability using the Boolean model does not allow the vulnerability criteria to be a continuous spectrum. For this reason, IHWP (inverse hierarchical analysis) fuzzy model has been used. The calculation of the score of the selected layers using the inverse hierarchical analysis method is in the form of the following mathematical relations:

Threat Assessment of Case Study In the studied sample, hard threats including air and missile attacks and bombings and people-oriented threats, i.e. demonstrations and riots have the highest probability and biological threats have the lowest probability. The possibility of air and missile attacks on infrastructures such as New Andisheh New Development Company, Gas Department, Electricity Department, Phase II Telecommunications Department, Police Headquarters, Andisheh Grand Bazaar, electrical substations and petrol pumps especially in the city center and also There is a possibility of the threat of demonstrations and riots in the area of ​​National Banks, Export, Housing in the central part of the city, Drekhri Street and Andisheh Big Bazaar, ABFA office. The possibility of bomb threat is also high in Andisheh Grand Bazaar, Basij Base, Andisheh Municipality, Telecommunication Department, two 230 KV substations in the southeast of the city.Vulnerability Assessment of Case Study In order to evaluate the vulnerability of the studied area against hard attack such as rocket launchers, ten indicators including property sensitivity, distance from sensitive and important infrastructure, road width, number of floors, population density, building quality, facade materials, access to medical centers and access to fire stations has been selected. 23.06 percent of the city plots are very low vulnerability, 26.78 percent are low vulnerability, 16.75 percent are medium vulnerability, 21.4 percent are high vulnerability and 12.01 percent are very high vulnerability. They have dedicated themselves. It is obvious that the parts located in the north and center of the city, such as sand mines in the northeast, Petropal gasoline pump on Imam Khomeini Boulevard in the center of the city, 63Kv electrical substation on Ostad Forozanfar Street, Phase 2 Telecommunication Department and 3, 4 and 5, and the social security hospital in the city center, which has high building and population densities, the quality of the restored, destructive building, a long distance to medical centers, less road width, more building height, degree of confinement, and more... have been, it had a high vulnerability score.

In this research, firstly, the package of sample threats studied in three steps including documentary studies, threat records and experts' opinions were extracted, and then using the AHP-FEMA scoring method, the threat of air-missile attack was selected as the base threat. Then IHWP model was used in GIS software. The results of these studies indicate that nearly 34% of the studied sample has a high and very high level of vulnerability against the threat of air attack. By examining the maps of the spatial distribution of uses and population, the distribution and distribution of relief and structural services, it is observed that the central parts of the city, which have a high population, are more vulnerable. The presence of high importance uses, low population density and high road width, suitable structural quality and high compatibility of uses causes a low score of vulnerability, and at the end, the solutions to reduce vulnerability according to the situation of the sample A case was presented.