آسیب پذیری بافت های فرسوده بخش مرکزی شهر تهران در برابر زلزله (مورد: منطقه ۱۲)

Extended Abstract Introduction Urban vulnerability to environmental disasters in countries with high environmental risks has converted into a severe issue. Even though the relevant literature indicates that corresponding studies urban historical deteriorated physical structures started seven decades ago, literatures pertaining vulnerability to earth quake go back to mid ۱۹۷۰s.Vulnerability to environmental risks, particularly to earthquake, has become an important issue for urban scientists,engineers and urban managers in countries and regions with perilous natural environment,as is the case for Tehran’s earthquake prone location. Metropolitan of Tehran, the capital city of Iran is an economic,communicative, and cultural hub not only in regional level, but also in national and international level. Geographically, Tehran is a city with an unsafe natural location between two great faults in the north and in the south.These faults particularly threaten the deteriorated and central textures. Metodology To help diminishing the vulnerability of this part of the city, in this work vulnerability of deteriorated area of central Tehran to earthquake, from the view of urban geography and considering the first level of urban crisis management ,is analyzed. The study deals with vulnerability of urban deteriorated physical structures located in zone ۱۲ to earthquake which is highly vulnerable. Separate analysis of seven factors, including population, age of the buildings, structure, surface area of the buildings, compatibility,access to open public areas,and accessibility, along with the dynamism of zone۱۲, are used with the suggested model to discuss the results of different variable combinations. The distributions of these variables in the regional blocks and the vulnerabilities of these blocks have been used in the desired functions to perform the analyses based on the total weight of the variables in the urban zones and blocks of the region. Discussion This study suggests that with regard to both “vulnerable created” and” vulnerable subjected” urban physical buildings located in central parts of Tehran,distance from open spaces, accessibility to vulnerable sites, age of the buildings and type of the construction materials are among the most important variables.The overall results prove the importance of all of the chosen variables in vulnerability of this specific zone.Taking into account the“Harmful Systems”and“Affected Systems”in the urban system and the deteriorated texture of central Tehran, accessibility to open public areas, access to roads, age of the buildings, and materials used in the structure, have respectively the highest impact on vulnerability to earthquake.Also,regional and ultra regional dynamism, considerably affect the deterioration rate and vulnerability to earthquake.Those mentioned variables along with areal economic distribution,dependent upon intra-regional economic activities concentrated in zones ۱۲ and ۱۳, leading to a daily flow of population of nearly ۸۰۰.۰۰۰ people in zone۱۲,have increased the Vulnerabilities of this part against earthquake.Resident population distribution in zone۱۲ follows a nonintensive pattern,which leads to a reduction in the role of this specific variable in the regional vulnerability to earthquake.Deterioration of the urban texture in zone۱۲, works as a“Harmful System”;and based on the theoretical framework used in this work,the dynamism of the activities is a“Harmful System”as well.This is resulted from the fact that the dynamism of activities is one of the major factors of deterioration of the textures in zone۱۲. Conclusion Analysis of the skeletal characteristics of zone۱۲showed that almost all of the skeletal characteristics all over this zone, are considered“Harmful Factors”when it comes to vulnerability to earthquake.But three variables of buildings’ age,texture pattern, and accessibility have higher significances.With the outcomes and results of this research,and its original idea, and considering the theoretical, and analytical framework used,it can be said that the deteriorated textures of central Tehran are in themselves, and also in connection to a set of small and large interconnected systems.At the same time,understanding these textures as“Vulnerable Systems”is not possible, due to the reason that “Vulnerabl Systems” always need“Harmful Systems”to complement them.Theoretically,understanding the vulnerabilities of the deteriorated texture of central Tehran is possible through a systematic view of“harmful and affected systems”in connection to other close and far textures of Tehran,as a“single urban body”.With this viewpoint,the resulting principles of this research can be used in analyzing the other parts of central Tehran.Therefore,using any of the existing theories without considering this point in the analysis is not useful in understanding the reality of vulnerability of city earthquake.

Keywords:

آسیب پذیری , بافت های فرسوده , بخش مرکزی. , زلزله , مخاطرات محیطی