Impact of human-made factors on exacerbate the consequences of natural hazards in metropolitan environments, by fuzzy logic and GIS application

One of the major problems in metropolitans of the world is Natural hazards. Natural hazards, particularly earthquakes always threaten human habitat and lives and in a short time can damage and casualties rather than leave a very broad. Between this, Iran due to placement in earthquake belt of the Himalayas, the Alps not exempt from this rule and are of the most disaster prone countries of the world. Accordingly, the overall urban environment on which it has deployment on faults, such as Tehran metropolitan with a population density up to attract the most vulnerable than are other parts. The one hand, man-made elements and non-compliance with certain principles in these places within places such as levels, lack of open spaces and low user area is highly vulnerable and probable losses resulting from earthquakes will doubled. So evaluate natural hazards with the impact of human-made factors in metropolitan environments is one of the main issues considered in this paper.This article evaluated to increases the intensity and quantity the vulnerability of urban areas and units of the earthquakes caused by human-made factors in five metropolitan area of Tehran. In this context, the combined knowledge of urban planning and fuzzy logic methods and Geography information system (GIS) is used. Criteria evaluation includes the main fault north of Tehran, subsidiary faults and the width of streets, open spaces and user area in the surface region. Research results by fuzzy method show that the rate vulnerability caused by an earthquake in Tehran metropolitan 5 area, including 4.82 percent with very low vulnerability, low vulnerability of 26.94 percent, 35.16 percent with moderate vulnerability, 27.96 percent with a significant vulnerability, 2.88 with high vulnerability, the vulnerability of 1.33 percent and 0.91 percent of very large buildings are quite vulnerable.