Debris flow susceptibility mapping at a regional scale has been the
subject of various studies. The complexity of the
phenomenon and the variability of local controlling factors limit
the use of process-based models for a first assessment. GISbased
approaches associating an automatic detection of the source areas
and a simple assessment of the debris flow
spreading may provide a substantial basis for a preliminary susceptibility
assessment at the regional scale. The use of a
digital elevation model, with a 10 m resolution, for the Canton de
Vaud territory (Switzerland), a lithological map and a land
use map, has allowed automatic identification of the potential source
areas. The spreading estimates are based on basic
probabilistic and energy calculations that allow to define the maximal
runout distance of a debris flow.