7 factors that affect or influence nature and speed of movement in mass wasting;
- Amount of water. The more saturated the material is the more likely it is to move. A mass of materials saturated with water moves more easily than a dry mass. ...
- Vegetation covers the area. Plants such as grasses, shrubs, and large trees, help to hold rock materials together, thus reducing their movement on the earth’s surface. ...
- Human activities. ...
- Tectonic movement. ...
What are the factors influencing mass wasting?
What are the factors that influence mass wasting?
- Composition of Slope Material. Another factor that determines mass wasting is the slope’s material. …
- Weight and Friction of Slope. A third factor that influences whether a slope will fail is the load or weight of that slope. …
- Regional Climate Conditions. …
- Water Content within Slopes. …
- Gravity.
What are the negative effects of mass wasting?
Mass movement, or mass wasting, has significant effects on humans, including loss of property, severe injury and death. This has become a larger problem as the human population grows and people have spread over more previously uninhabited land. The effects are also greater in underdeveloped countries that lack zoning laws, information and disaster preparedness.
What is the major force that causes mass wasting?
There are several other ways friction can be reduced along a slope: wildfires, removal of vegetation, or adding too much water.Gravity is probably the ultimate driving force of mass wasting. The force of gravity pulls all things on the planet toward the center of the Earth. Without gravity, mass wasting would not occur.
What are two main sources of mass wasting?
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.
What is the best definition of mass wasting?
Mass wasting is when the deposited consolidated or unconsolidated sediments having a variety of sizes, shapes, and origins are transported downslop...
What are the 4 types of mass wasting?
Four types of mass wasting are slump, rockslides, debris flow, and earthflow. One of the main distinctive criteria amongst these is the presence of...
What can cause mass wasting?
There are three main causes of mass wasting. The first one is the water content which acts as a lubricant to increase mobility. The second one is t...
What are 3 factors that contribute to mass wasting?
Three factors that contribute to mass wasting are water content, gravity, and triggering mechanisms. The amount of water is critical since water ac...
What is the steepest angle a slope can be before the ground will slide?
The steepest angle a slope can be before the ground will slide is about 35 degrees, called the angle of repose.
What are the factors that influence mass wasting?
Ultimately, this comes down to the dynamics of two factors: gravity and steepness of slope. The steeper the slope, the greater potential for gravity to pull objects down. The shallower the slope, the less effect gravity has on pulling objects down. There are several factors that influence mass wasting, but ultimately it is a battle between friction ...
Why does water increase in soil?
But too much water lubricates the individual grains of sediment decreasing friction between each grain, so the possibility of mass wasting increases. The increase of water within the soils can come from over watering, pipe or swimming pool leaks, or prolonged stormy weather.
What causes mass wasting?
There are several factors that influence mass wasting, but ultimately it is a battle between friction and gravity. If the friction on a rock is stronger than gravity for a particular slope, the rock material will likely stay. But if gravity is stronger, the slope will fail.The steeper the slope, the stronger the friction or rock strength must be ...
How does water affect slope stability?
The amount of water in the soil is a major factor in the stability of a slope. When you build a sand castle, water is needed to build the walls and towers. That is because water has surface tension and is attracted to each other. This allows you to build towers greater than the angle of repose. So a little water can actually prevent slopes from sliding. But too much water lubricates the individual grains of sediment decreasing friction between each grain, so the possibility of mass wasting increases. The increase of water within the soils can come from over watering, pipe or swimming pool leaks, or prolonged stormy weather. In Utah and many mountainous regions, spring runoff of snow melt increases the water content within the soil.
What is the force that pulls all things on the planet toward the center of the Earth?
The force of gravity pulls all things on the planet toward the center of the Earth. Without gravity, mass wasting would not occur. But unlike many of the other factors, humans have no influence or control on gravity.
What is the driving force of mass wasting?
Gravity . Finally, gravity is the driving force of mass wasting. The force of gravity pulls all things on the planet toward the center of the Earth. But unlike many of the other factors, humans have no influence or control on gravity. For more information on what causes landslides in Utah, click here.
What is mass wasting?
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. Landslide triggers may include:
What is a landslide made of water-saturated rock debris and soil?
A Debris Flow is a type of landslide made up of a mixture of water-saturated rock debris and soil with a consistency similar to wet cement. Debris flows move rapidly downslope under the influence of gravity. Sometimes referred to as earth flows or mud flows.
What are the triggers of a land slide?
Landslide triggers may include: Intense rainfall. Rapid snowmelt. Earthquake. Volcanic eruption. Stream or coastal erosion. The runout of a mass wasting event depends on the volume of material, water content, and slope steepness. Diagram of mass wasting processes.
What is the term for a mass of rock or ice that falls suddenly under the force of gravity?
An avalanche occurs when a mass of rock or ice falls or slides suddenly under the force of gravity.
What is the term for the sliding of rock material down a mountain?
Without the base, the outer sections of the mountain slumps down as a unit or multiple units. A rockslide is another example of mass wasting of a slope. A rockslide is the sliding of rock material down a mountain. It is similar to a slump, but a rockslide does not move along a curved surface like a slump.
Why does mass wasting occur?
With this understanding, we see that the causes of mass wasting occur when gravitational force overcomes the resistive forces of the mountain. And, since gravitational pull is always constant, then we see that mass wasting occurs when something changes the mountain's ability to resist gravity.
Why do mountains have mass wasting?
Now, we mentioned that mass wasting is mainly due to gravity. So, we see that mountains have an ongoing tug-of-war with gravity. Gravity is constantly trying to pull rock and debris down the slope of a mountain. At the same time, the resistive forces of the mountain, including the cohesive strength and internal friction between the materials, referred to as the mountain's shear strength, constantly pulls back against gravity.
What is debris flow?
A debris flow is the movement of a water-laden mass of loose mud, sand, soil, rock and debris down a slope. Some debris flows move slowly while others can pick up momentum on steep slopes and reach speeds of 100 miles per hour or greater, sweeping away anything in their path, including trees, bridges, houses or roads.
What forces pull back against gravity?
At the same time, the resistive forces of the mountain, including the cohesive strength and internal friction between the materials, referred to as the mountain's shear strength, constantly pulls back against gravity. The shear strength works to maintain the slope's stability and keep the materials in place.
What is mass wasting?
Mass wasting is a type of erosion, and it is capable of making big changes to the side of a mountain. These changes can happen suddenly, as in one minute the rock is there and the next it is gone, or it can happen more slowly over time.
What is Ch 10.?
Ch 10. Sedimentary Rocks: A Deeper Look
How do you know if a landslide is a mass wasting?
Landslides have several identifying features that can be common across the different types of mass wasting. Note that there are many exceptions, and a landslide does not have to have these features. Displacement of material by landslides causes the absence of material uphill and the deposition of new material downhill, and careful observation can identify the evidence of that displacement. Other signs of landslides include tilted or offset structures or natural features that would normally be vertical or in place.#N#Many landslides have escarpments or scarps. Landslide scarps, like fault scarps, are steep terrain created when movement of the adjacent land exposes a part of the subsurface. The most prominent scarp is the main scarp, which marks the uphill extent of the landslide. As the disturbed material moves out of place, a step slope forms and develops a new hillside escarpment for the undisturbed material. Main scarps are formed by movement of the displaced material away from the undisturbed ground and are the visible part of slide rupture surface.
What causes a landslide to occur?
It could be rapid snowmelt, intense rainfall, earthquake shaking, volcanic eruption, storm waves, rapid- stream erosion, or human activities, such as grading a new road. Increased water content within the slope is the most common mass-wasting trigger. Water content can increase due to rapidly melting snow or ice or an intense rain event. Intense rain events can occur more often during El Niño years. Then, the west coast of North America receives more precipitation than normal, and landslides become more common. Changes in surface-water conditions resulting from earthquakes, previous slope failures that dam up streams, or human structures that interfere with runoff, such as buildings, roads, or parking lots can provide additional water to a slope. In the case of the 1959 Hebgen Lake rock slide, Madison Canyon, Montana, the shear strength of the slope may have been weakened by earthquake shaking. Most landslide mitigation diverts and drains water away from slide areas. Tarps and plastic sheeting are often used to drain water off of slide bodies and prevent infiltration into the slide. Drains are used to dewater landslides and shallow wells are used to monitor the water content of some active landslides.
What is a landslide?
Geologically, landslide is a general term for mass wasting that involves fast-moving geologic material. Loose material along with overlying soils are what typically move during a mass-wasting event. Moving blocks of bedrock are called rock topples, rock slides, or rock falls, depending on the dominant motion of the blocks.
How does the gravitational force change?
In the figure, the force vectors change as the slope angle increases. The gravitational force doesn’t change, but the shear force increases while the normal force decreases. The steepest angle at which rock and soil material is stable and will not move downslope is called the angle of repose. The angle of repose is measured relative from the horizontal. When a slope is at the angle of repose, the shear force is in equilibrium with the normal force. If the slope becomes just slightly steeper, the shear force exceeds the normal force, and the material starts to move downhill. The angle of repose varies for all material and slopes depending on many factors such as grain size, grain composition, and water content. The figure shows the angle of repose for sand that is poured into a pile on a flat surface. The sand grains cascade down the sides of the pile until coming to rest at the angle of repose. At that angle, the base and height of the pile continue to increase, but the angle of the sides remains the same.
What is mass wasting?
Mass wasting is the downhill movement of rock and soil material due to gravity. The term landslide is often used as a synonym for mass wasting, but mass wasting is a much broader term referring to all movement downslope. Geologically, landslide is a general term for mass wasting that involves fast-moving geologic material.
What dam was used to dam the Spanish Fork River?
The 1983 Thistle landslide (foreground) dammed the Spanish Fork River creating a lake that covered the town of Thistle, Utah. The slide covered Hwy 6 and the main railroad between Salt Lake and Denver.
How are mass wasting events classified?
Mass-wasting events are classified by type of movement and type of material, and there are several ways to classify these events. The figure and table show terms used. In addition, mass-wasting types often share common morphological features observed on the surface, such as the head scarp—commonly seen as crescent shapes on a cliff face; hummocky or uneven surfaces; accumulations of talus —loose rocky material falling from above; and toe of slope, which covers existing surface material.
What is true of submarine landslides?
Identify statements true of submarine landslides and tsunamis. -As a submarine slide occurs, it can push water into a sea-surface bulge ahead of its path; this can result in tsunami initiation. -As a submarine slide occurs, it can result in a depression in the sea surface above the slide.
What are the consequences of forest fires followed by heavy rains?
Forest fires followed by heavy rains are likely to result in severe mud and debris flows.
What is the steepest angle at which unconsolidated sediments can sit without slipping downhill?
The angle of repose is the steepest angle at which unconsolidated sediments can sit without slipping downhill. Classification of mass-movement events is based on. the type of material involved (rock, regolith, snow, and ice).
Where does solifluction occur?
Solifluction occurs in areas underlain by permafrost. During the summer, when the top few meters of sediment thaw, the soggy material can slowly move downhill.
Which force becomes greater, resistance or downslope?
the downslope force becomes greater than the resistance force.
