An Estimation of the Trend of City Horizontal Expansion within Seismic Faults and natural Risky Regions and its Consequences (Case Study: Saqqez county in Kurdistan province)

A review on different research about human habitats indicates that geology structure and environmental characteristics have affected city establishment and dwelling selection. With this in mind, the place of establishment (plains, foothills, so an) of a greater part of human habitats generally and urban habitats specifically has encountered such phenomena as quakes, landslides due to its relative proximity with the faults. The occurrence of numerous earthquakes in different places of the country within recent decades and their negative consequences especially on urban centers is a clear proof to this argument. Saqqez city in Kurdistan province due to its location with the proximity of many faults (Saqqez river faults, Valikhan river, Sonata and so an) is one of the places that from one hand the natural sea-bed features of its location has caused the possibility of accessibility to this property. From another perspective the horizontal expansion of the city in direction of abovementioned faults has increased the accessibility. Now this writing tries to investigate the horizontal and physical development of the city in wake of quakes. For this respect, by using Topography – digitally maps and geology at the scale of 1:250000 and by using geographic information systems including Arc GIS and Arc view soft ware's and historical seismographic data , the isoseismic curve maps and expanse measurement of quake risk have been delineated. The results of the research hold that in accordance with seismography map and examining the quake occurrence timing in the region, there is a higher possibility of earthquakes in Saqqez. Most importantly, the city has been developing hastily towards unstable heights and minor faults in western and northern parts. An accordingly editing strategic and essential measure in the course of reducing quake risks by optimum orientation towards horizontal expansion is absolutely crucial.