Debris flow susceptibility mapping using frequency ratio and seed cells, in a portion of a mountain international route, Dry Central Andes of Argentina

Debris flow and floods represent one of the main natural hazards that impact transport infrastructure, causing serious damage, economic losses and hinder regional economic development. These processes are eventually associated with massive traffic cuts and direct damage to road structures. To enable the prevention of such consequences, this paper employs statistical modeling techniques, various instability factors and geomorphological mapping to generate debris flow susceptibility maps in a portion of an important route on the Dry Andes of San Juan in the Agua Negra River basin, Argentina. A debris flows inventory map was prepared using satellite images and field checks. The debris flows inventory was randomly divided into a model dataset 80% (47 debris flows) and remaining 20% (12 debris flows) data was used for validation purpose. The instability factors chosen that influence debris flows occurrence were: elevation, slope angle, slope aspect, solar radiation, topographic wetness index, stream power index, topographic position index, Melton ruggedness number, terrain ruggedness index, sediment transport capacity index, plan curvature, profile curvature, lithology, distance to road and proximity to stream. Using these factors, six different models of debris flow susceptibility were calculated by Frequency ratio (Fr). Lithology (igneous complex) was found to be important debris flows-related factor in the study area. The precision of the results was evaluated by receiver operating characteristic (ROC) analysis. According to the area under the curve (AUC) the models of all flow track and natural breaks and all flow track and geometrical interval were 0.83 and 0.84, respectively, showing a practically identical predictive capacity.