Debris flow susceptibility mapping at a regional scale along the National Road N7, Argentina

Valérie Baumann, Emmanuel Wick, Pascal Horton, Michel Jaboyedoff

In the proceedings of: GEO2011: 64th Canadian Geotechnical Conference, 14th Pan-American Conference on Soil Mechanics and Geotechnical Engineering, 5th Pan-American Conference on Teaching and Learning of Geotechnical Engineering

Session: Landslides

ABSTRACT: A first assessment of debris flow susceptibility at a large scale was performed along the National Road N7, Argentina. Numerous catchments are prone to debris flows and likely to endanger the road-users. A 1:50,000 susceptibility map was created. The use of a DEM (grid 30 m) associated to three complementary criteria (slope, contributing area, curvature) allowed the identification of potential source areas. The debris flow spreading was estimated using a process- and GIS-based model (Flow-R) based on basic probabilistic and energy calculations. The best-fit values for the coefficient of friction and the mass-to-drag ratio of the PCM model were found to be µ = 0.02 and M/D = 180 and the resulting propagation on one of the calibration site was validated using the Coulomb friction model. The results are realistic and will be useful to determine which areas need to be prioritized for detailed studies.

RESUMEN: Se realizó un primer estudio de susceptibilidad a los flujos de detritos a escala regional a lo largo de la Ruta Nacional N7 (Argentina), donde numerosas cuencas producen flujos de detritos afectando la ruta. Se utilizó un modelo de elevación digital con una resolución de 30 m y tres criterios para discriminar las áreas fuentes (pendiente, área de aporte y curvatura del terreno). El recorrido de los flujos de detritos se estimó con un modelo basado en SIG (Flow-R) utilizando algoritmos de probabilidad y de energía. Se eligieron dos de los mejores valores (µ = 0.02 and M/D = 180) para el coeficiente de fricción y el fimass-to-drag ratiofl del modelo PCM, estos a su vez fueron validados con el modelo de fricción de Coulomb. Los resultados son coherentes y ayudan a definir las áreas que necesiten un estudio más detallado.

Please include this code when submitting a data update: GEO2011_525

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