Downhill creep

Creep may appear to an observer to be continuous, but it really is the sum of numerous minute, discrete movements of slope material caused by the force of gravity.

Friction, being the primary force to resist gravity, is produced when one body of material slides past another offering a mechanical resistance between the two which acts to hold objects (or slopes) in place.

Water is a very important factor when discussing soil deformation and movement.

The presence of water may help the hillside stay put and give it cohesion, but in a very wet environment or during or after a large amount of precipitation the pores between the grains can become saturated with water and cause the ground to slide along the slip plane it creates.

The expansion portion pushes downhill, then the contraction results in consolidation at the new offset.

This can be seen in churchyards, where older headstones are often situated at an angle and several meters away from where they were originally erected.

When a hillside contains much flora their roots create an interlocking network that can strengthen unconsolidated material.

Design engineers sometimes need to guard against downhill creep during their planning to prevent building foundations from being undermined.

Pilings are planted sufficiently deep into the surface material to guard against this action taking place.

For shallow to moderate slopes, diffusional sediment flux is modeled linearly as (Culling, 1960; McKean et al., 1993)

On long timescales, diffusive creep in hillslope soils leads to a characteristic rounding of ridges in the landscape.