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recommendations with emphasis on spontaneous landslides and debris flows are
given below.
3.2 The Matrix of Mass Movement Processes and Triggering
Parameters
3.2.1 Basics
In mountainous regions several processes of mass movements appear, reaching from
sediment transport in rivers over debris and mud flows to landslides, rock falls and
avalanches. All these processes are triggered by varying combinations of parameters
in different ways. For instance, rising temperatures mean rising snow lines which
probably increase the danger of flooding especially during the winter season but also
may decrease the hazards of avalanches at lower altitudes. This chapter focuses on
the processes of spontaneous landslides and resulting debris and mud flows, but a lot
of the conclusions may be figuratively valid also for other mass transport processes.
The
basic disposition
(Fig.
3.1
) against sediment transport processes, espe-
cially landslides and debris or mud flows in young fold mountains (e.g. the
Alps) is comparatively high in this stage of “Mountain-development”. Due to
topographic attributes (high gradients) erosion is a natural phenomenon. In the case
of spontaneous, more or less shallow landslides and mud flows, basically tasks like
10
1
9
8
10
7
6
5
100
4
3
1000
2
1
0
10000
Base disposition
Variable disposition
Impact
Fig. 3.1
Scheme: Frequency of mass transport processes (especially spontaneous landslides and
debris flows). The amount and intensity of precipitations (shown by the return period) is only
one triggering factor. The basic and the variable susceptibility of the area, reflected by selected
parameters, have to be considered in this matter
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