GIS-based automated mapping hazardous exogenous processes in the Tunka depression

The authors consider automated mapping and spatial analysis of hazardous exogenous processes using a digital elevation model, space images and GIS technologies. A highly detailed map of dangerous exogenous processes within the Tunka depression has been created. At the initial stage, using digital terrain model data, the maps of natural characteristics, which cause the distribution of exogenous processes, were made. This is an elevation map, steepness of slopes and slope aspect maps, normalized difference vegetation index map (NDVI), topographic humidity index and slope length (LS) factor maps. Additional information was obtained from the analysis of space images, landscape conditions and field data. Certain sets and ranges of indicators that characterize the spatial distribution of each class of hazardous exogenous processes were chosen. Seven classes of the most intense hazardous exogenous processes were revealed. The main hazardous exogenous processes in the territory of the Tunka depression were noted on a vector basis using the method of spatial analysis in geographic information systems. Fluvial, slope erosion, and cryogenic-slope classes are most common. Fluvial class of exogenous processes is most dangerous due to mudflows within the valleys of small and temporary watercourses. Slope erosion class is represented by gully erosion, and cryogenic-slope is most often manifested in the form of solifluction. The local danger is represented by screes and rock falls, which are included in the group of gravitational-slope processes.