Weathering is a process affecting fault gouges in the Swiss Alps.
Smectites are one of the alteration products under Alpine climate.
Weathering is considered to be one of the main factors leading to
rock instability failure. Preliminary analysis of recent rockslides
within gneissic rocks in Switzerland indicates that accelerations
of movements are linked to precipitations, without any possibility
of excess pore water pressure.
Rockslide movements induced by water seepage can be explained by processes
like crushing or weathering, and by the strain effect in both the
fractures walls and the infilling material. Such processes lead to
soil-like behaviour of the faults. Weathering processes leading to
precipitation of smectite appear to be an indicator of slope evolution.
The process make possible a change in mechanical properties, which
in turn leads to landslides.