Analysis of the city's vulnerability factors against earthquakes, a case study of the 4th district of Tehran

Doctoral thesis in the field of geography, urban planning

Abstract

Iran is considered one of the most earthquake-prone countries in the world, and its cities have suffered a lot of damage in relation to this natural phenomenon. Due to its geographical location, Iran is always exposed to various natural disasters that affect different parts of it from time to time and leave harmful effects. Iran's location on the Alpine-Himalaya earthquake belt has caused earthquakes to be considered as one of the disasters that cause the most damage in the country. Such an event always causes a lot of environmental changes and leaves a lot of damages.

       Earthquake risk in Tehran is very high due to its geographical and tectonic location, the existence of many faults around it, the occurrence of many destructive historical earthquakes in its area and other tectonic and geological evidences. A look at the history of Iran's earthquakes shows that Tehran, with its old name, has been destroyed several times in large historical earthquakes. Despite the activity of the Tehran area and the recording of numerous large and small earthquakes in this area, no destructive earthquakes have occurred in this area in the current century, and this absence of earthquakes should be considered a sign of the accumulation of energy in the ground, which increases the probability of a devastating earthquake.

Region 4 of Tehran has experienced an average annual population growth greater than the whole of Tehran during the last three decades and is one of the populous areas. is considered This region has significant diversity in terms of economic, social and cultural context of its residents. On the one hand, in this area, there are districts and neighborhoods such as Khak Sefid and Shemiran No, which are the residences of the poorest and lowest-income social strata of Tehran. In these neighborhoods, the density of residential units, the small and interwoven fabric of residential spaces, low literacy and illiteracy, the size of the household is larger than the region and city, and the density of people in each residential unit can be seen. On the other hand, neighborhoods and areas such as Pasdaran and Tehranpars can be seen next to the previous neighborhoods, whose residents are contrary to the previous indicators, i.e. desirable urban space, large houses, Basaman crossings, high per capita income and so on. are beneficial Due to the existence of this spatial difference and social, economic and physical differences in region 4, this region can be a good example for evaluating and analyzing the impact of various factors on urban vulnerability to earthquakes. Due to the fact that cities have different foundations and characteristics from other human settlements, if the comprehensive principles that require the establishment of a city in a specific place are neglected, they can be potentially dangerous biological points for creating crises in the event of natural disasters. Cities have a body, each of which houses an activity, and all of them make up the urban space and give it an identity.

Nowadays, in the new perspectives of crisis management planning, risk-crisis management has been considered as the superior attitude in which the approach to earthquakes has changed from risk to vulnerability, from reaction to proactive action, and from a one-dimensional phenomenon to an all-round category. Therefore, the earthquake crisis has become a part of everyday life, which does not have adverse results in itself, but what makes this phenomenon a disaster is the failure to prevent its impact and the lack of preparation to deal with its consequences. Since the investigation and decision-making in comprehensive issues such as the earthquake, the consequences of which include all aspects of the city, the analysis based on one factor does not have the necessary efficiency, and it is necessary to consider a set of factors according to the importance of each of them. Therefore, in this research, modern planning models such as Analytical Hierarchy Process Model (AHP) and Strategic Analysis Technique (SWOT) have been used, which have this capability.

Examining the results obtained from this research shows that different factors can have different effects on the damages caused by earthquakes, such as the influence of environmental factors such as distance from the fault, soil type, and slope percentage. And its stability is more than other factors. Physical-spatial factors such as type of materials, construction life, building density, distance from open space and compatibility of uses and so on.After the environmental factors, they are on the second level of influence in the aggravation of casualties and destruction of the earthquake event. Also, the impact of socio-economic factors such as net residential density, population density and access to urban infrastructure cannot be denied in the vulnerability of urban areas to earthquakes. Administrative-institutional factors (various stages of crisis management including relief, rescue and resettlement operations) such as the presence of temporary accommodation and proximity to fire stations are also in the next ranks of aggravating damages and casualties caused by a possible earthquake. The result of the case study of region 4 in reducing the vulnerability of cities can lead to lessons in preparation and planning against earthquakes using appropriate tools and software. The long-term goals will be achieved when the safety of the city against the risks of earthquakes is considered as a goal in all levels of planning (from land use to architecture), and the intermediate level, i.e. urban development and urban planning, can be one of the most efficient levels of planning to reduce vulnerability to earthquakes. Urban planning, relying on social, economic, physical and environmental conditions, adopts tools to improve the environment. Determining the privacy of dangerous areas, compiling rules and regulations specific to densities and uses, separating land, paying special attention to the role of open spaces and accesses, considering the principles of mass-space, contiguity and compatibility of uses are among the measures of urban planning that are effective in evaluating and reducing vulnerability in urban areas.

Key words: urban planning, earthquake, vulnerability, crisis management, Tehran Region 4

Chapter 1

General Research plan

-1- Introduction

Since the beginning of writing this thesis, several terrible earthquakes have happened, including in Haiti, which left about 30,000 people dead and injured, and in addition, it led to many social and economic consequences, such as looting of people's property, leaving children unattended, destroying buildings, and causing financial losses and casualties. In other countries, including Iran, mild but large earthquakes occurred in the cities of Kerman, Zarand and has happened All this while we still have the tragic disaster of the Bam earthquake in our minds, but despite many discussions and warnings from officials, experts and experts, many fundamental or practical measures have not been taken in the country yet. Except for some actions of the government and municipalities in the cities of the country, such as credit measures for the renovation and improvement of worn-out structures, emphasis on the retrofitting of newly built buildings and so on. which was not enough. This is despite the fact that nowadays the attitude towards natural hazards and crisis management, including earthquakes, floods and other hazards, which are increasing in number every day, has changed from a one-sided view and only emphasizing the retrofitting of buildings and the creation of multi-purpose rescue and rescue bases to an all-round and holistic approach. Therefore, strategies appropriate to this systemic and comprehensive approach will also be necessary. In the present research, it has been tried to collect the viewpoints and approaches governing the issue of natural hazards both in developed countries and in developing countries, to introduce the dominant and new approach that has been operationalized and established in advanced countries, and by using new urban planning methods and techniques, to present the necessary strategies regarding how to deal with natural hazards such as earthquakes, which of course will be possible considering the conditions and facilities available in countries such as our country. And the importance of paying attention to it in an earthquake-prone country like Iran is discussed, and then fundamental and applied researches and studies conducted in Iran and other parts of the world are mentioned. In the following, an attempt is made to state the objectives, hypotheses and main questions of the research, the importance and value of the problem, the methods of gathering and analyzing information, the limitations and applications of the research. What makes this phenomenon a disaster is the failure to prevent its impact and the lack of preparation to deal with its consequences.