What is the difference between erosion and mass movement? Definition: 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.
Which mass movement is the fastest?
Landslides and avalanches can move as fast as 200 to 300 km/hour. Figure 3. (a) Landslides are called rock slides by geologists.
Can trigger a sudden mass movement?
A mass movement can occur any time a slope becomes unstable. Sometimes, as in the case of creep or solifluction, the slope is unstable all of the time and the process is continuous. … Shocks and vibrations – A sudden shock, such as an earthquake may trigger slope instability.
Where is soil erosion currently the most severe?
The majority of Caribbean countries, Brazil, Central African countries, and parts of Southeast Asia are experiencing severe erosion on more than 70% of their arable land. In contrast, Australia, Canada, Saharan countries, Russia, and most of the European Union are only losing 3% of their arable land to severe erosion.
How do humans can contribute to mass wasting?
Humans can contribute to mass wasting in a few different ways: Excavation of slope or its toe. Loading of slope or its crest. Drawdown (of reservoirs)
What is the slowest mass wasting process?
The slowest and least noticeable, but most widespread of the slow mass wasting categories is creep. Creep involves the entire hillside, and is characterized by very slow movement of soil or rock material over a period of several years.
What type of mass movement is the slowest fastest?
Creep is the slowest of all the mass movements and moves the most soil out of all the mass movements. The only way to detect soil creep is to observe the fences, buildings, and other surface objects that may be in that area.
What are 4 types of 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.
What causes a debris flow?
Debris flows can be triggered in a number of ways. Typically, they result from sudden rainfall, where water begins to wash material from a slope, or when water removed material from a freshly burned stretch of land. … Another major cause of debris flows is the erosion of steams and riverbanks.
What is the most important factor in causing mass movements?
Gravity: the most important factor in causing mass movements. Water: adds weight to the slopes and reduces friction between the soil particles.
What is the difference between an Earthflow and a debris flow?
A debris flow is the movement of a water-laden mass of loose mud, sand, soil, rock and debris down a slope. … An earthflow is a flow of fine-grained material that typically develops at the lower end of a slope. Earthflows often ooze down a mountain at a pace of a slow-moving earthworm.
What state has the most soil erosion?
Many soils in the area are highly erodible, and erosion is appreciably higher than the national average. * The Corn Belt States experience some of the highest erosion rates in the country: in 1977, Iowa cropland lost an average of 9.9 tons of soil per acre; Illinois, 6.7 tons per acre, and Missouri, 10 9 tons per acre.
How serious is soil erosion in the United States?
Soil erosion on agricultural land in the United States does not pose an immedi- ate threat to the Nation’s ability to produce food and fiber. However, erosion is impairing long-term soil productivity in some areas and is the largest contribu- tor to nonpoint source pollution of the Nation’s waterways.
Why is poor quality soil a problem?
Soil degradation leads directly to water pollution by sediments and attached agricultural chemicals from eroded fields. Soil degradation indirectly causes water pollution by increasing the erosive power of runoff and by reducing the soil’s ability to hold or immobilize nutrients and pesticides.
What are the negative effects of mass wasting?
Mass movements affect the following elements of the environment: (1) the topography of the earth’s surface, particularly the morphologies of mountain and valley systems, both on the continents and on the ocean floors; (2) the character/quality of rivers and streams and groundwater flow; (3) the forests that cover much …
How can we prevent mass wasting?
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.
Which change can lead to slope failure?
Which change can lead to slope failure? the shearing stress on the material exceeds its frictional resistance (or shear strength) .
What triggers mass-wasting?
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.
Where is the largest landslide located?
In 1980, the explosion of Mount St. Helens in the state of Washington, United States, triggered the largest (on land) landslide ever recorded. Mount St. Helens is a stratovolcano situated in the Cascade Mountains, 88 kilometers northeast of Portland.
What are 2 examples of mass movement?
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.
What is fall in mass movement?
The basic types of landslide movement are: Fall. This is generally characterized by rapid or extremely rapid rate of movement with the descent of material characterized by a freefall period. Falls are commonly triggered by earthquakes or erosion processes.
How do you survive a debris flow?
You can’t stop or change the path of a debris flow. However, you may be able to protect your property from floodwaters or mud by use of sandbags, retaining walls or k-rails (Jersey barriers). In mud and debris flow areas, consider building channels or deflection walls to try to direct the flow around buildings.
What is the difference between a debris slide and a debris flow?
Debris flows differ from slides because they are made up of « loose » particles that move independently within the flow. A slide is a coherent block of material that « slides » over a failure surface. … Debris flows have larger particles – at least 50% of a debris flow is made up of sand-size or larger particles.
How fast does a debris flow move?
Debris flows can travel at speeds up to and exceeding 35 mph and can carry large items such as boulders, trees, and cars. If a debris flows enters a steep stream channel, they can travel for several miles, impacting areas unaware of the hazard.
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