CREEP

Surface creep is the slow downhill movement of soil and rock debris. It is usually not perceptible except through extended observation. The term can also describe the rolling of soil particles by wind along soil surface.

Creep- the very slow, usually continuous movement of regolith down slope. Creep occurs on almost all slopes, but the rates vary.

Creep. Soil creep is a slow and long term mass movement.

There are four different types of mass movement:

• Rockfall. Bits of rock fall off the cliff face, usually due to freeze-thaw weathering.
• Mudflow. Saturated soil (soil filled with water) flows down a slope.
• Landslide. Large blocks of rock slide downhill.
• Rotational slip. Saturated soil slumps down a curved surface.

A landslide is the movement of a mass of rock, debris, or earth (soil) down a slope. A rockfall is the action of boulders, rocks or slabs of rock falling or toppling.

Rockfall processes can be described as the detachment and downslope movement of individual rocks as well as intact rock masses that fragment during their fall into blocks with variable dimensions. Rock masses that fall down the slope are mostly characterized as rock avalanches.

Such factors include: weathering or erosional debris cover on slopes, which is usually liable to mass movement; the character and structure of rocks, such as resistant permeable beds prone to sliding because of underlying impermeable rocks; the removal of the vegetation cover, which increases the slope’s susceptibility …

What Causes Rockfall? A number of geologic processes set the stage for rockfalls, including glaciation, weathering, and bedrock fractures. Tectonic stresses and erosion cause granite rock to fracture. Rockfalls later occur along these fractures.

Rockfall occurs when rocks are broken down by freeze-thaw weathering, this loosened material is vulnerable to the elements. This can occur more so when a wave cut notch is created at the foot of the cliff by wave action, causing the overhanging rock to be unsupported and more likely to fall.

Rockfalls occur where a source of rock exists above a slope steep enough to allow rapid downslope movement of dislodged rocks by falling, rolling, bouncing, and sliding. Rockfall sources include bedrock outcrops or boulders on steep mountainsides or near the edges of escarpments such as cliffs, bluffs, and terraces.

Mass movements are important natural geomorphic agents that shape mountain landforms and redistribute sediment and debris to gentler terrain and water bodies. The earth mass may move in a number of ways: falling, toppling, sliding, spreading, flowing, or by their combinations.

Mass movement control must be primarily preventive: e.g., mapping vulnerable zones, drawing up a land use plan, banning building work or any modification of slopes, and protection in the form of coppice forests.

Mass movements are defined as processes of erosion, transport and accumulation of material that occur on both gentle and steep slopes mainly owing to gravitational forces. Thus, mass movements results in levelling and forming of landscapes. Different types of mass movements occur such as landslides or solifluction.

Mass wasting is the movement of rock and soil down slope under the influence of gravity. Rock falls, slumps, and debris flows are all examples of mass wasting. Often lubricated by rainfall or agitated by seismic activity, these events may occur very rapidly and move as a flow.

1 Types of Mass Wasting. The most common mass-wasting types are falls, rotational and translational slides, flows, and creep. Falls are abrupt rock movements that detach from steep slopes or cliffs.

Flow – The debris is moving downslope as a viscous fluid. A mudflow is a flowing mixture of debris and water, usually moving down a channel. Slump – involves movement along a curved surface, the upper part moving downward while the lower part moves outward.

Rockslides are a type of translational event since the rock mass moves along a roughly planar surface with little rotation or backward tilting. Rock slides are the most dangerous form of mass-wasting because they incorporate a sudden, incredibly fast-paced release of bedrock along a uniform plane of weakness.

e) Spreads: A spread is an extension of a cohesive soil or rock mass combined with a general subsidence of the fractured mass of cohesive material into softer underlying material. The rupture surface is not a surface of intense shear. Spreads may result from liquefaction or flow (and extrusion) of the softer material.

Mass movements can be very dangerous because they can happen very quickly and involve entire hillsides. Sometimes a mass movement will dam a river. A lake will form behind the dam. When the dam bursts, the lake will drain causing catastrophic flooding.

landslides. In landslide: Types of landslides. A spread is the complex lateral movement of relatively coherent earth materials resting on a weaker substrate that is subject to liquefaction or plastic flow.

In recent years, the ease of travel and communication, the global recession and new conflicts have contributed to rising numbers of migrants across the globe. These numbers encompass individuals that are moving internationally, along with those that leave their country of origin, but remain in their home region.

Creep is the imperceptibly slow, steady, downward movement of slope-forming soil or rock. Movement is caused by shear stress sufficient to produce permanent deformation, but too small to produce shear failure.

Avoiding Rockfalls And Rock Avalanches Avoidance techniques include building tunnels, realigning or rerouting roads, and elevating structures above the point of danger. While these approaches are the most protective solution, they bear the highest cost to install, along with ongoing maintenance costs.

What To Do After a Landslide

1. Stay away from the slide area.
2. Listen to local radio or television stations for the latest emergency information.
3. Watch for flooding, which may occur after a landslide or debris flow.
4. Check for injured and trapped persons near the slide, without entering the direct slide area.