Challenges of physical Development of Songhor affected by Glacial Deposits accumulation and Slop Instability

The physical development of cities located in the mountainous often occurs towards the hillsides. The hillsides as a result of glacial erosion in the Quaternary period have deposits characterized by permeability and grain separation, which lead to instability and environmental changes if combined with the steep slope, abundant rainfall, and earthquakes. Songhor city is a typical case of such cities. In this study, the slope instability potential in Dalakhani basin was investigated. For this purpose, the developing extent of glacial sediments was identified through the regression analysis of temperature and elevation as well as the sediment investigation. By defining instability indicators and using the fuzzy dimensionless method to homogenize parameters, the map of slope instability potential was produced. The findings of this study revealed that out of 1.7 square kilometers development, from 1987 to 2011, Songhor city expanded to the slopes prone to instability up to1 square kilometer. The map of slope instability potential also showed that half of the city was located in the area with high potential of slope instability. Furthermore, with respect to the physical development of Songhor to the high slopes, it is necessary to identify the areas prone to slope instability.