مجله مدیریت مخاطرات محیطی
سال چهارم شماره 1 (بهار 1396)

The aim of this research was to study the capabilities of social media for crowdsourcing of earthquake hazards management. The capabilities were identified in the three stages of pre-earthquake stage, acute-earthquake stage (the first 24 hours), and post-earthquake stage. The research method was Delphi. The study populations were managers and experts in the field of crisis and social media, which 22 people from this community were chosen as sample. In the first phase of Delphi, interviews were conducted with experts. Then the interviews were analyzed and coded. In the second phase, a questionnaire based on the findings of the first phase was sent to the experts and their responses were analyzed. The process was repeated in the third and fourth phases. The experts reached a consensus on some of the capabilities of social media, which is characterized as follows: Pre-earthquake stage (“Seeking ideas and opinions”, “Warning”, “Rescue”, “Monitoring the performance of managers” and “Training before the crisis”), Acute-earthquake stage (“Warning”, “Rescue”, “Documentation”, “Public Participation stuff” and “Monitoring the performance of managers”), and Post-earthquake stage (“Rescue”, “Monitoring the performance of managers”, “Public Participation stuff”, “Crisis map”, “Estimated damage”, “Shortages announcement”, “The identification of the original inhabitants of the earthquake area”, “Collecting information on the dead, missing, wounded, etc”).

Prevention from hazard is always a better option than its management and treatment. Our country, due to its geographical and natural position, is among 10 countries exposing to natural disasters. Earthquake, as the most considerable hazard, has caused significant damages yet due to existing several active faults in Iran. Hence, predicting earthquakes, and considering preparations to mitigate the vulnerability of building structures, is a top priority for designers, builders and regulators. Particularly, high-rise buildings are very important to reduce such vulnerabilities because of their high occupation area, population, effects on the environment, and special structural characteristics. In this paper, we enumerate various architectural and structural parameters that affect the optimization and stability of tall buildings against loads. We then investigate the effect of architectural form on increasing structural efficiency and stability against seismic loads. The research is quantitative, and applies modeling and simulation techniques. To assess the effect of parameters accurately, reliable architectural (Rhinoceros) and structural (SAP2000) software were used. Although, based on the results, the effect of the number of plan sides is less clear in some parameters such as inter-story drift, and maximum displacement, it reveals more obvious differences, and explicit relation between the number of sides and material weight in structural fundamental period, and structural weight per unit area. Generally, structural plans containing more sides model optimized forms due to have less weight, and present less stiffened, and more flexible behavior.

Nowadays, the quality of the environment is one of the most important concerns of the administrative and planning institutions. It is useful to perform the assessment and evaluation the amount of resident’s satisfaction as well as studies over the status of the strengths and weaknesses of the urban environment. There is no doubt that studying the desire of the population to find high quality places to live is one of the main reasons of such researches. This research was aimed to check the quality of the urban environment from the perspective of citizens in different 5 regions of district 18 of Tehran Metropolitan. The method of this research is an analytical- descriptive method. The Case study of the statistical community is the residents of district 18 of Tehran. Afterward, 300 persons of this community were selected using Cochrane, and spatial cluster sampling method. Methods, technologies and tools to collect data and information have been based on library studies, observations, discussion, and questionnaire. For the analysis step, different tests such as single test sample, Kolmogorov–Smirnov test -Smirnoff test, Friedman test, regression, and Kruskal output have been used. The quality of the environment in different 5 regions has been performed using GIS based on Kruskal tests output. The results show that the quality of the urban environment of district 18 was 2.45 based on the citizens’ views, which is a medium quality. Among the studied criteria, the functional criterion of district 18 is lower than the environmental and aesthetic criteria. The spatial analysis among the 5 areas has shown that: the quality of the environment in area 1 is in the first place, areas 2 and 3 are in the second place, and areas 4 and 5 are in the third place. This result emphasizes that the quality of urban environment is a multidimensional fact. Satisfaction of the quality of environment is happened once the quality of integrated environmental management is realized in all aspects. In addition, the quality of the urban environment isn't just objective, but it has mental aspects. Every citizen has understanding of their environment, and attention to this matter can improve the quality of the environment.

Population increasing and irregular Immigration to Tehran, which followed by developing construction, has been increased the hazard exposure of the city of Tehran. In addition, historical urban spreading of Tehran, and surrounding by the important active faults, increase the risk of earthquake consequence. After a destructive earthquake,  a capital city such as Tehran encounters to fire, subsidence, water leakage and failure of many services. Earthquake early warning system as a solution of risk reduction has been proposed in recent decades. A limited number of countries such as Japan, America, Mexico, Romania, have almost applied this system and some countries such as Turky, Korea, China, and Italy are developing EEWS. This paper was conducted for examination of the possibility or impossibility of using the earthquake early warning system of Tehran. Consequently a feasibility study of theoretical network has been investigated. Also sensitivity analysis of some EEWS parameters has been done. Finally, according to the Tehran’s active faults, we concluded that it is possible to provide alarm time for many destructive earthquakes.

Urban runoff is one of the destructive phenomena, which can destroy urban structures. The facilities and equipment of ABFA in region 1 of Tehran are vulnerable for runoff during rainfalls due to the extent of upper field areas, high slope, increase of precipitation compared to other regions of Tehran, ground leveling, and inability of watercourses to surface water control. This study has been done using 10 meters resolution DEM, 1:100000 geologic maps, regional soil maps, statistical and meteorological data of study area between 1972 and 2013, population statistics of 2006, spatial data from aid and service centers, hazardous areas, and land use/land cover information. This research contains different steps. First, effective sub-criteria of vulnerability of the study are have been introduced. Then, they have been weighted using AHP-Fuzzy algorithm, and the impact of each criteria over the vulnerability of these parameters was defined using the TOPSIS algorithm. The results show the following parameters have the most impact over the increase of the vulnerability on northern part of Tehran, which all caused to prevent facilities installation in high depth: density of risk centers (gas stations and power transmission lines), urban decay, slope, relative population density, the facilities and equipment conditions (in terms of diameters and applied depth), and existence of north Tehran watercourses (Darakeh, Darband, Velenjak, Maghsoudbeyk, Jamshidieh, Darabad, and Larak). Furthermore, the results indicate that in case of an emergency in central, and northern part of study area, which have dense water supply installations, there are no specific places to install the emergency water supply structures. Contrariwise, in southern part of study area, having more urban green spaces lead to find more space to install the water supply structures in case of emergency.