Metropolis Explosion and Sprawl development of Tehran region within the framework of urban Decline Theory

Urbanization has been manifested as a profound transformation in the economic and social life of mankind centuries ago. One of these, is the theory of urban decline theory of Berg et al. that Introduced in 1982 which is defined in four stages (urbanization, suburbanization, anti-urbanization and re-urbanization). Tehran Metropolitan Region is the study area in this research. In this research, the process of the explosion of the metropolis and the emergence of urban decline in the main city (Tehran) and urban sprawl have been studied as an objective reflection of the development of the periphery during the years 1355-1959. This research is based on Retroductive strategy, in terms of purpose is based on fundamental researches and in terms of its method, is based on analytical research. Also, the research is carried out in a meta-analysis and based on secondary population data of the Center of Statistics as a measure of scale and information of outreach schemes, and has used the traditions of quantitative and qualitative research methodology. For analyzing the data, the Directional Trends the Moran Spatial Correlation model, Getis-Ord Gi, and for measuring the growth of the city in the studied periods, were used from the Shanon and Holdren entropy models in the ArcGis10.3 statistical software. The research findings indicate that "Tehran Metropolitan region" has begun its suburban stage since the 50s Shamsi and after the 70s Shamsi it faced the process of urbanization (decline). The spatial representation of these two processes has been manifested in a sprawl form.