Gravity is the main force responsible for mass movements. Gravity is a force that acts everywhere on the Earth’s surface, pulling everything in a direction toward the center of the Earth.

Mudflow usually contains 60% water and the rest is silt and suspended particles submerged in it. Due to the particles, it has a high viscosity due to which it does not flow as water flow. The answer is Mudflow.

Mass movement is the movement of earth materials called regoilth down a slope under the influence of gravity. Water and gravity cause the soil to move slowly downhill. This movement is shown on the features of the surface.

Creep is the very slow downhill movement of rock and soil. It occurs most often on gentle slopes.

Creep, in geology, slow downslope movement of particles that occurs on every slope covered with loose, weathered material. Even soil covered with close-knit sod creeps downslope, as indicated by slow but persistent tilting of trees, poles, gravestones, and other objects set into the ground on hillsides.

Creep can affect internal stresses in two ways. It can reduce existing internal stresses to the extent that they are of a continuous nature, and it can create its own new internal stresses when materials with different creep characteristics interact in a given cross section.

Cover exposed soil with a variety of plants — trees, shrubs, perennials and annuals — to create a barrier that stops soil movement from both wind and water. The plants’ roots will hold the soil in place, as well. Lay mulch or stone between plants to provide additional coverage of exposed dirt.

Creep can also be caused by the expansion of materials such as clay when they are exposed to water. They also aid in absorbing the excess water in the soil to help keep the slope stable.

Most vegetated slopes in humid climates are subject to soil creep, and there are many indicators that it occurs. Poles and fence posts often tip away from a slope a few years after they are emplaced. Trees growing on a slope usually have trunks with sharp curves at their bases.

Creep is a type of deformation, and metals that undergo excessive creep deformation can oftentimes fail completely. Unfortunately, creep-related failures happen frequently and are hazardous to both property and human life.

Soil creep can cause severe damages to buildings and infrastructure and even affect urbanistic development if appropriate measures are not taken. To manage the associated risk, it is necessary to map the affected areas and estimate the landslide activity.

This natural tendency is called creep. Several factors play in the initiation and progression of creep in a material, including temperature, time, stress, and alloy composition. The rate of deformation due to creep is called creep rate.

Creep failure is the time-dependent and permanent deformation of a material when subjected to a constant load or stress. This deformation typically occurs at elevated temperatures, although it may occur under ambient temperatures as well.

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.

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.

Which type of mass wasting moves rapidly and can be deadly? SELECT TWO. That’s right! Flows (debris flows especially) and rock falls can move very quickly, making them dangerous.

Mass-wasting events are triggered by changes that oversteepen slope angles and weaken slope stability, such as rapid snow melt, intense rainfall, earthquake shaking, volcanic eruption, storm waves, stream erosion, and human activities. Excessive precipitation is the most common trigger.

Landslide Warning Signs

• Springs, seeps, or saturated ground in areas that have not typically been wet before.
• New cracks or unusual bulges in the ground, street pavements or sidewalks.
• Soil moving away from foundations.
• Ancillary structures such as decks and patios tilting and/or moving relative to the main house.

Mass wasting is prone in the spring-time when snow melt, water saturation, and runoff is greatest. Also the type of climate will help determine the type of mass wasting. Humid climates tend to have slides, where water-saturated slopes fail and fall. Drier climates tend to have rocks that fall; especially early spring.

Landslides can cause flooding by forming landslide dams that block valleys and stream channels, allowing large amounts of water to back up. This causes backwater flooding and, if the dam fails, subsequent downstream flooding.

Erosion is the dislodging of sediments that initiates their movement. Particles may then be moved away by sediment transport agents such as wind, water, glaciers, etc. Mass movement refers to earth materials moving downslope under the influence of gravity, as in rockslides, mudflows, slumps, etc.

Types of mass wasting include creep, slides, flows, topples, and falls, each with its own characteristic features, and taking place over timescales from seconds to hundreds of years.

Mass wasting – is movement in which bed rock, rock debris, or soil moves downslope in bulk, or as a mass, because of the pull of gravity. 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.

The most destructive type of mass movement is a landslide, which occurs when rock and soil slide quickly down a steep slope. Some landslides may contain huge masses of rock, while others may contain only a small amount of rock and soil.

Engineering solutions include barriers and retaining walls, drainage pipes, terracing the slope to reduce the steepness of the cuts, and immediate revegetation. Rockfalls can be controlled or eliminated by the use of rock bolts, cables, and screens and by cutting back slopes to lesser gradients.

As already noted, we cannot prevent mass wasting in the long term as it is a natural and ongoing process; however, in many situations there are actions that we can take to reduce or mitigate its damaging effects on people and infrastructure.

A rock fall are the fastest of all landslide types and occurs when a rock falls through the air until it comes to rest on the ground—not too complicated.