مسکن و محیط روستا (Oct 2023)
Risk analysis of landslides for identifying development constraints in the physical structure of rural settlements; case study: Savadkooh region, Mazandaran
Abstract
Landslides, following floods and earthquakes, are one of the most significant natural hazards in the world, causing considerable human and financial losses annually. The Savadkooh region, located in the northern foothills of the Alborz Mountains, is susceptible to landslides due to climatic, geomorphological, geological, hydrological, and human-biological factors. The aim of this research is to conduct a risk analysis of landslides to identify development constraints in the physical structure of rural settlements in the Mazandaran Savadkooh region. To achieve this goal, 319 landslides were identified and analyzed based on records, field observations, satellite images, and other relevant data. Precipitation was found to be a key and central factor in the occurrence of more than 180 landslides in the region. In this study, the MARCOS model was used as one of the new multi-criteria decision-making methods for landslide hazard zoning in the area. Using GIS software and combining layers of slope, aspect, geology, land use, distance from roads, rivers, faults, precipitation, and earthquakes, a landslide hazard zoning map of the region was prepared in five classes: very low, low, moderate, high, and very high. The model output shows that over 63% of the area and 146 villages are located in zones with moderate to very high landslide hazard, mainly at elevations below 2000 meters, with slopes of 20 to 30 degrees, rich in clay minerals (Shemshak Formation, Sari Continental Formation, Quaternary alluvial deposits), and within 100 meters of roads and rivers. Validation of the MARCOS model using the density ratio method showed an accuracy rate of 89.1%, indicating a very good fit between the model results and field observations, as well as geotechnical and geophysical studies conducted in the area. The occurrence of 283 landslides in zones with moderate to very high hazard, 38 landslides in the built-up areas of villages, and 137 landslides within 300 meters of village settlements in these zones confirms the validity of the study's results. The findings can be used to develop comprehensive regional development plans, progress and settlement plans for rural areas, and rural settlement plans to identify areas at risk of landslides and to identify opportunities and constraints for the physical development of rural settlements.
