Mass Wasting

By Dylan Black

Rock Fall

Caused when weathering loosens a rock on a very steep slope. Eventually, the rock fragment become unsupportable and fall, roll, or bounce down to the bottom of the slope.

Landslide

An instantaneous collapse of a slope along a generally flat, sliding plane that may or may not involve the liberating effect of water or clay. The material that begins to slide down takes the form of a rigid mass that is suddenly displaced altogether without any fluid flow. However, the presence of liquid may perhaps aid in the landslide, and many landslides have been the outcome of a heavy rain that saturates the slope, severely increasing the possibility of a landslide.

Earth Flow

A piece of a water-saturated slope moves only a small distance downhill. This typically occurs during or immediately after heavy rainfall. At the point in which the flow originates, an undoubtable scar is typically cut into the surface of the slope, with either cracks or prominent over-steepened scraping force.

Mudflow

Created in arid/semiarid country where heavy rain immediately followed by drought leads to a cascading runoff too voluminous to be adsorbed into the soil. Fine pieces of debris are picked up from the hillsides by the runoff and at the bottom of the valley, where the mudflow continues onto.

Slump

Established by a slope failure in which a portion of regolith moves downward as well as rotates outward along a curved slide plane that shows its concave side upward. The upper portion of this material tilts down and back, while the lower portion goes up and out.

Flow

When a section becomes unstable, thanks to the inclusion of water, and begins to flow downhill. This flow is fairly rapid, but becomes more gradual and sluggish as it spreads out. The center of the mass is typically moving rapidly, while friction slows the outward portions of the mass.

Creep

The slowest and least perceptible (quite fittingly named in that case) form of mass wasting, consisting of a very gradual downhill movement of soil and regolith so unobtrusive that it can typically only be identified and proved by other pieces of evidence. The entire slope is usually involved. Creep is so actually such as prevalent phenomenon that is occurs all over the world across sloping land. Although most notable on steep, lightly vegetated slopes, it can also occur on gentle slopes that have dense plant cover. Wherever weather materials are available for movement on land that is not flat, creep is a persistent form of mass wasting.