Jordkrypning

Jordkrypning, often translated as soil creep, is a slow, continuous form of mass wasting affecting hillsides. It is the gradual downslope movement of soil and weathered rock particles under the influence of gravity. This movement is typically imperceptible over short periods, but over time it can lead to significant displacement of surface materials.

Several factors contribute to jordkrypning. The most significant is the repeated action of freeze-thaw cycles in temperate and alpine regions, and wet-dry cycles in drier climates. Water entering the soil freezes, expands, and lifts soil particles. When the water thaws or dries, the particles settle back down slightly downslope from their original position. Repeated cycles lead to a net downslope movement.

Other contributing factors include the burrowing activity of animals, the growth and decay of plant roots, and the lubrication effect of water saturating the soil. The presence of a distinct soil horizon or a layer of impermeable clay can also facilitate creep by providing a slippery surface for downslope movement.

Evidence of jordkrypning can be observed in subtle landforms. Trees on slopes may appear to be leaning downslope, with their trunks curving upwards at the base in a phenomenon known as "pistol butt" trees. Fences, walls, and utility poles may also tilt or be distorted over time. Soil creep is a ubiquitous process on most slopes and plays a role in the overall geomorphological evolution of landscapes. It is distinct from faster mass wasting processes like landslides or rockfalls.