In studying the origin and evolution of landscape, various scales are used both in space and time. The A. suggests distinguishing the following effective time scales of landform evolution : formative extreme events and secular processes, clusterings
: way to destinity (planation), continuous adjustment to new conditions, coexistence of diverse forms controlled both by tectonic and climatic factors as well as by lithology.
thresholds, duration, and areal extent of process activity. It is useful to view process relationships from both a geomechanical and behavioural perspective. It is proposed that the stress/ resistance/strain relationship can be represented by corresponding
to the establishment of temporal and magnitude frequency are presented and illustrated. Both empirical and deterministic methods are discussed. In particular, advances in empirical modelling are used to show the extent to which the probability of landslide occurrence
programme is suggested, which emphasises the continuing and spatially-distributed feedback between form and process. This is applicable to a wide range of geomorphological problems, in both unconsolidated materials and hard rock.