Geomorphological Hazards and Settlement Instability: A Case Study of Razg Village in Birjand County

Introduction
Geomorphological hazards are considered among the environmental processes that cause serious disruption in human activities all over the world. The extreme vulnerability of villages to natural hazards is one of the characteristics of many rural areas of the country, among which many villages are exposed to natural hazards due to the geographical conditions in which they are located. Therefore, it is necessary to carry out geomorphological risk studies of rural settlements. Obviously, if there is no proper scientific and practical management in dealing with natural hazards, the human damages caused by them will be many times. In the meantime, geomorphological hazards are natural disasters whose disastrous effects and consequences can be reduced with the help of predetermined planners. The type of geomorphological hazards in different regions is affected by hydrogeomorphological, climatic and geo-structural factors, and due to the diversity of Iran in terms of the mentioned cases, the type of geomorphological hazards in different regions of the country has a great diversity. Geomorphology is one of the earth sciences that helps managers, planners and other custodians of economic and technical issues in choosing the best places for the establishment and development of settlements and other constructions.
Methodology
In this article, the geomorphological hazards of Razg village settlement in Birjand city were investigated and analyzed through field visits and GIS files using Arc Map software. Therefore, in order to prepare the studied maps for the village of Razg, it was prepared through the slope file of South Khorasan province, then a population diagram map was produced. Then, through the slope of the file, the DEM map of the village was cut and the topographic map, slope map and direction map were prepared. On the produced map of the village, studies were emphasized on the village of Razg.In order to analyze geomorphological hazards, height classification map, surface classification, boundary map, river map, fault map, geological map and soil map were produced and analyzed in each part. According to the generated slope and direction maps, risks, focused tourism map and extensive tourism map, the map of agricultural and grazing potentials of the district and village of Razg were examined and scientifically analyzed.
Findings
The studied area is Razg village located in Bagheran village and 12 kilometers south of Birjand. Razg village is located at an altitude of 1800-2000 meters. In terms of distribution, Razg village is located in a place where several villages are concentrated at a very short distance. The village of Razg is located on the slope of the mountain and between two valleys, the valley which is located in the eastern part of the village of Razg is wider and the main road gives access to the village, the valley which is located in the northern part has more soil cover and It is greener and landslides are caused by the fact that parts of the river path were closed, in case of heavy rains, we will witness the possibility of landslides and floods in this part of the village, especially constructions should not take place on landslides, it is necessary Create a path for the flood to pass through the landslide. The fault map of Bagheran village shows that 24 faults have been identified in the region, most of the faults are located in the north, center and southwest part of this village, in the village of Razg, there is a fault with southeast to northwest direction from the eastern parts of this village. The village has passed. Razg village is located in the classification of the slope above 30 degrees, which is not suitable for its settlement. The village of Razg has been exposed to landslides and floods in terms of settlement. According to the altitude classification in Bagheran village, Razg village is located at an altitude of 1834 meters above sea level. According to the altitude classification in Bagheran village, Razg village is located at an altitude of 1834 meters above sea level. According to the map of the slope and direction, a concentrated tourist map was prepared for Bagheran village and Razg village, which Razg village does not have the potential of concentrated tourists of ability 1 and ability 2.
Discussion and Conclusion
In this research, with the aim of investigating the geomorphological hazards of Razg village, Birjand city, it has been investigated. In each geographical location, planning is done according to the natural features and geomorphology. Planning is not possible without nature and without paying attention to the potentials of the region. In all local, city, provincial and national planning, special attention should be paid to nature. The findings of the research and the produced maps show that the village of Razg is located in an unsuitable place with a slope of more than 30 degrees. The fault that passed through the village of Razg had an intersection where the location of the fault; Erosion and water flow have caused the formation of waterways and landslides. The rock units of the region, including split basalts, play an important role in the landslide of Razg village. In the northern and northeastern parts of Razg village, there is a slippery valley that has blocked the slippery surface of the river bed. In case of heavy rain, floods and landslides will occur and the access road to the village will be blocked. It is suggested that the river route be dredged from the slippery surface. Due to the passage of the fault and the proximity to the faults located in the area, in the event of an earthquake, 100% of the buildings in the village will be destroyed. It is suggested to plan and implement the safety of the buildings of Razg village before the occurrence of natural disasters with the management of provincial and local officials, of course, this proposal should be planned at the national level for all cities and villages of Iran. In terms of altitude classification, Razg village is located at an altitude of 2000-1800 meters. Scientifically in evaluating the slope and direction; Razg village does not have the potential of tourism and any planning in the field of tourism is scientifically rejected, the buildings of the village are destructive and the structures are built on unstable slopes. It is suggested that in future research, the level of resistance of the structures of Bagheran villages against the occurrence of natural disasters should be studied and safe spots should be chosen for the settlement.