Spatial analysis of Social vulnerability of households against Earthquake (case Study: 6 Region of Tehran)

IntroductionToday the identification, control and prevention of loss of life and property damage in relation with hazards is one of the most important issues. This issues requires special attention and planning in this area. Earthquake, is considered as one of the hazards and natural disasters that Creates serious damage to land and structures. This damages are caused the much loss of life. The earthquake is a natural phenomenon that occasionally vibrates the earth and causes damages. The earthquake could be a disaster due to unfamiliarity and inability of human when confronting it. It will be more intensive when unreasonable action of human occurs. The social factors have determined effects on household vulnerability as compared to other elements which must be investigated. The 6 region of Tehran is more vulnerable to possible events of earthquake because of centrality in Tehran, existence of ministries, embassies, higher education institutes, health centers, hospitals and big economic companies. Therefore, with regard to the importance of this issue, the recent research will evaluate and analyses the social vulnerability among households in neighbors of 6 region of Tehran.
Methodology The recent study is on the basis of a descriptive-analytical method. Statistical population of the research consists of total households of 6 region of Tehran including 29051 families. The number of data for sampling were estimated 331 households according to Cochran formulae from which on the basis of classified sampling method and optimum allocation and ratio of number of blocks in each neighbor were determined. The validity of questionnaire was confirmed using experts and faculty members. The reliability of awareness scales and reaction readiness against earthquake hazards using Cronbach's alpha were 0.751 and 0.79, respectively, which were acceptable. A numeric code was allocated to each question to quantitative it and hot spot technique was used to determine the upper and lower points and Kriging interpolation was employed to generalize the results of the point value to the area and fuzzy technique was used for indexation. Also, for combining layers, weight of each layer is required. There are different techniques for determining weight. In this study Delphi technique was used. Finally, to measure, saw techniques have been used
Results and discussionTehran's sixth region is one of the 22 districts of Tehran. This region, because of the centrality and the existence of important land use, have a great importance in Tehran city. Kriging interpolation was used to regionalize the physiological factors of social vulnerability for different indices viz. sex, and age, physical and mental disability. Sex vulnerability was high in Shariati, Vlie-Asr, Ghaem magham- Sanaee and Abbasabad neighbours. Age index vulnerability was less in the region and it was lesser in the neighbours such as Vlie-Asr and Laleh Park as compared to others. The physical and mental disability was low in the region and it was higher in the neighbours like Vlie-Asr, Iranshahr and Laleh Park but lesser in Amirabad, Gandi and Argentine-Saee as compared to others. The results show that a heterogeneity was found among households and it was more in south and north of the region. Ownership vulnerability in Iranshahr, Abbasabad, Behjatabad and Ghaem magham- Sanaee was higher as compared to other neighbours. The results revealed that the awareness of head of households was more in accordance with earthquake and a negative relationship among awareness, sex, ownership, ethnicity and vulnerability were found using Pearson correlation coefficient. Although, a positive relationship among education, income and vulnerability were found.
The results revealed that preparedness of the head of household was less in relation to earthquake and an indirect relationship was found between preparedness and sex, age and ethnicity. Although, a direct and positive relation was discovered between preparedness and education, income and ownership. Kriging interpolation method was used to regionalize the cognitive factors of social vulnerability in preparedness and awareness indices against earthquake. Accordingly, the vulnerability in terms of preparedness and awareness indices in the area was moderate and the household’s awareness was more as compared to preparedness for response in 6 regions.
Kriging interpolation method was also used to regionalize the demographics factors of social vulnerability in education level and population density indices against earthquake. The results showed that regionalization of the demographics factors the education level was high, the population density was moderate, and it was high in southern neighbors. The vulnerability in different dimension was as follows: It was high in Shariati, Vlie-Asr, and Abbasabad neighbors but it was low in Amirabad, Ghezel Ghaleh and Jahad square at physiologic dimension; It was high in Gandi, Iranshahr, University of Tehran and Behjat Abad but was low in Amirabad and Nosrat neighbors at demographics dimension; It was high in University of Tehran, Amirabad, Gandi, Behjat Abad and Abbasabad but it was low in Vlie-Asr, Laleh park, Fatemi and Ghaem magham- Sanaee at cognitive dimension. The total Vulnerability: the total Vulnerability (Social one) was high in Shariati, University of Tehran, Behjatabad, Ghaem magham-Sanaee, Gandi, and Abbasabad (0.6 to 0.8) but it was low in Amirabad and Ghezel Ghaleh (0.2 to 0.4) and it was moderate in other neighbours (0.4 to 0.6).
ConclusionAccording to the results of the study, it could be concluded that the neighbors of 6 region of Tehran did not have the same vulnerability against earthquake due to various socio-economic conformations. For example, Amirabad, Ghezel Ghaleh and Shiraz had less vulnerability but Shariati, University of Tehran, Behjatabad, Ghaem magham-Sanaee, Gandi and Abbasabad had high vulnerability as compared to other neighbors. In overall, it should be noted that the management activities need to reduce the vulnerability on the basis of characteristics of neighbors. Another important point in the results of the investigation is the situation and spatial distribution of each of the dimensions of social vulnerability. Based on the maps produced The highest balance and the lowest vulnerability is related to the economic dimension.