Spatial sensitivity assessment based on landslide trigger factors

Kelkit Valley has landslide density higher than the Turkey average. Accumulated snow in winter rapidly melt at the spring months and it cause water outlets on high slopes in front of these plateau and this triggers large catastrophic landslides. As a result of observation and literature investigations, it has been determined snow stay on the ground for a long term, after melt in the spring due to solar radiation it being infiltration and finally it passing flow all of which triggers landslide. It is known that landslide sensitivity is high on slopes where this effect is high. The purpose of this study is determine slope sensitivity in terms of trigger factor. For this purpose, the study area is physically divided into 3600 slope units. The M-AHP method was used to for determine the snow adhesion, infiltration, and flow sensitivity of these units, including the factors and the impact levels on this sensitivity via the expert opinion. Multi Resolution Valley Bottom Flatness, altitude and aspect parameters were used for snow adhesion. Topographic Wetness Index (TWI), Hydrologic Soil Group (HSG) and solar radiation parameters were used for the infiltration. Altitude, slope and Hydrologic Soil Group (HSG) parameters were used for the flow. The slope units that the highest decision is determine was made for adhesion, infiltration and flow were determined the spatial sensitivity based on main triggering snowmelt. In the results obtained, it was found that the spatial sensitivity is higher in the slopes having the highest value of the output of more than one model (e.g., snow adhesion-infiltration-flow). It was determined these slopes especially correspond to the starting regions of the northern block landslides. It has been found that the adhesion-infiltration slopes, which prepare convenient ground, correspond to the old-landslide, and infiltration-flow slopes correspond to the transfer zones of the landslides especially the northern block. Due to the high infiltration on the northern slopes, the water content be high and the landslide is triggered on these slopes. Apart from this, the adhesion-flow slopes effect in the southern block of the study area more