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 GISbased
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 ? = 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.