عنوان مقاله [English]
The refore the necessity of understanding of effective environmental factors has an important role in the formation of rural settlements.The importance of this lies in the fact that each year a large budget is spent on the constructing of rural settlements organization, developing of connecting roads and services, etc.Unfortunately, many of the expenses are made without considering the ( Factoe (and identifying areas with a high risk of natural disasters, on which the villages are located.
The importance of the study lies in the fact that environmental conditions affecting the formation of rural settlements and the villages which are at the risk of natural disasters should be identified.Therefore investigating the effects of environmental factors associated with rural settlements and identifying the natural disasters in these areas are essential.In this research rural settlements of Marivan in one of the most active tectonic regions of Iran are considered as a Case Study which are identified for a variety of natural disasters in Iran.This city is located in the West of Kurdistan, on the western border with Iraq.This area is relatively located in position with a high seismic risk. And in terms of tectonic it is located on Marivan- Esfandaghe fault.Therefore, the identification of factors affecting the sustainability of rural settlements is very important.
Materials and methods of research:
A variety of instruments and methods has been used to achieve the aims of the research; In the first stage Research instruments including: topographic maps 1:25000, geological map 1:100000, surface water with a scale of 1: 50,000 and data on groundwater as well as ETM satellite images were collected from different organizations. In the second stage by using ARC GIS software, required layers were derived from digital maps mentioned above.
At this stage, layers such as watershed, Canals and surface water, Province fault Maps, places about to slip and silde were determined.And then by using GIS spatial analysis capabilities the classification Map was prepared and the position of rural areas was determined on it.
In the third stage to study for studied natural hazards under investigation, in order to determine the role of each of the various factors in the occurrence of natural disasters, the AHP method was used.At first Raster maps related to any of the factors in cell size of 20 x 20 m was produced by the use of vector information.
After producing raster maps, fuzzy standardization was applied on each map so that the effective range on the occurrence of any phenomenon is defined between 0-1. In addition to the standardization of map`s unit, it specifies the role of special ranges in each factor. Linear standardization functions were used to define the effective ranges between 0-1. Standardized layers were multiplied by the weights which were given to them based on experts` opinions and the final weight was obtained for each layer. Finally the final weight of each of the effective layers on the occurrence of natural hazards was collected together and the final map of each phenomenon was prepared in the studied area.
In the fourth stage, by the use of the final earthquake hazard zonation layers landslide and flood and combining the layers with an index overlap, the final layer of natural hazards of Marivan was prepared and rural areas were transferred on it. Finally the villages at risk of natural hazards were identified.
Because of being mountainous and locating in a tectonically active region the area of study (Marivan_Asfandeqhe) is the most seismic areas in the country. And as a result of the earthquake, various natural hazards occur there. That's why it’s unstable in terms of environmental factors. And this issue has also been effective in distribution of rural settlements.
To investigate the relationship between the natural factors and the formation of rural settlements, first the position of the villages to the three factors is reviewed. Then the zoning of the risks caused by environmental factors is investigated. Investigating the relationship between environmental factors and the position of rural settlements and finally zoning of natural hazards in the city of Marivan shows that the formation of rural settlements in this city has taken place due to its natural sources and fertile soil and the possibility of having gardening activities.
Local climate and the possibility of having gardening activities have caused the Continuity of Living in rural areas in this city. Having access to water sources has happened without considering the risk of flooding, So that villages near the main river routes have faced with the risk of floods. It also seems that Location selection in this area has been regardless of Natural hazards such as earthquakes. Because this area is one of the most Earthquake-prone regions in Iran. While Most of the villages are close to the main fault and relatively in high risk of earthquake.
Investigating the environmental factors in association with Distribution or accumulation of rural areas and the role of these factors in occurrence of natural hazards in the city of Marivan shows that, slope, due to its direct effect on other environmental factors is the most important factor in the stability of villages.
Since most old villages are located in areas with high slope.And this factor in addition to the activities of gardening and handicrafts was very effective in residence continuation of people.Moreover, the natural hazards occurred in low slope areas.
The results of Bahrami’s research have revealed that the establishment system in the rural environment of Kurdistan, specifically the city of Sanandaj, is not compatible with the requirements of modern developments. In the city of Sanandaj, natural causes (Climate, high altitude and steep) despite the limitations of Locational- Spatial subsistence and lack of logical ideas in rural planning have also doubled the problems of countryside development in Sanandaj.