Miami Killian Senior High School



Lithosphere KQ3 & KQ5KQ3A: What natural and man-made processes contribute to different types and causes of mass-movement on slopes?Rock weathering processes and the accumulation of debris on slopes.Rock weathering process is when rock dissolves, is worn away, or broken down into smaller pieces. There are three types of weathering process: mechanical, organic, and chemical. Mechanical is the physical breakup of rocks, for example: frost shattering, when water goes into the cracks of rocks and when it freezes it either makes the crack large or breaks the rock. Organic is when plants break up the rocks, for example: growing roots or plant acids that dissolve the rock. Chemical weathering decomposes rocks and mineral, for example: carbon dioxide in water and moist air dissolves rocks; the outcome can sometimes be canyons or caves. Larger rocks with more mass, because of gravity, have the momentum to fall to the bottom of slopes. Smaller rocks tend to stay on the higher end of slopes. These rocks, large or small, become extremely unstable when it rains causing them to fall crash into each other and break. ?Causes of mass movement: flows and slides includingRock falls:Rockslides are influenced by mechanical weathering and gravity. After a heavy rain, pressure downward or outward can cause rockslide to occur. ?LandslidesHeavy rainfall and earthquakes on sloped areas may cause the soil to slip, creating a landslide.Earth slumpsSlump is a form of mass wasting; it is when a coherent mass moves a short distance down a slope. It is caused when the base of the slope is removed. ?Soil creepSoil creep occurs when water freezes and lifts particles of soil and rocks but when it thaws the solid and rocks aren't in the same place. Gravity causes the rocks and soil to settle a little further down the slope. ?SolifluctionSolifluction, is very similar to soil creep. It occurs during the summer thaw, in which the frozen permafrost beneath it traps water in soil there. This causes the waterlogged sludge to move downward because of gravity. ?MudflowsMudflow occurs when water saturates the ground in heavy and long periods, causing a thick liquid (mud) to flow downhill. ?Human influences include deforestation and building. Deforestation is when forests are clear on a mass scale. This interferes with the quality of the land and increases the emission of carbon dioxide into the atmosphere; it also destroys habitats of animals causing them to be endangered or even extinct. Deforestation is responsible for 20% of the greenhouse gas emissions. Also, by removing trees humans also remove the source that turns carbon dioxide into oxygen.?Industrial activities has multiple negative effects on the environment. Oil spills destroy ocean life and habitat. Chemical runoff from the industries causes eutrophication. The amount of carbon dioxide that industries emit increases global climate change and creates a hole in the ozone layer. A theoretical introduction backed up by a case study, e.g. Hong Kong, Rio de Janeiro, Sarno in Southern Italy, Himalayan Foothills. During the past 40 years, close to 20 percent of the Amazon rainforest has been cut down—more than in all the previous 450 years since European colonization began. The percentage could well be far higher; the figure fails to account for selective logging, which causes significant damage but is less easily observable than clear?cuts. Scientists fear that an additional 20 percent of the trees will be lost over the next two decades. If that happens, the forest's ecology will begin to unravel. Intact, the Amazon produces half its own rainfall through the moisture it releases into the atmosphere. Eliminate enough of that rain through clearing, and the remaining trees dry out and die. When desiccation is worsened by global warming, severe droughts raise the specter of wildfires that could ravage the forest. Such a drought afflicted the Amazon in 2005, reducing river levels as much as 40 feet KQ3B: How are sudden mass-movements managed?Slope management policies including: Slope angle reductionIf an area has a steep slope, it is prone to landslides and other mass movements. With a slope angle reduction, soil can be moved in to reduce the steep angle. Bringing in land to an area that has been cut away may also reduce the risk of mass movement.AfforestationAfforestation is the process of planting trees and vegetation in areas where there is currently none grown in order to stabilize the land by implementing leaf litter and root structure. Replanting trees may increase drainage into the ground and prevent water from eroding the soil.DrainageDrainage systems are assigned to areas in which landslides may occur. The drainage system diverts water away from slopes and into established waterways by making troughs in the land that diver the water away or by using pipes.Surface protectionBy covering vulnerable areas with vegetation and other natural material, the land can be protected from flowing water or air. KQ5A: What pressures has human activity placed upon the resources of the lithosphere?Land as a resource under pressure from:Urban sprawl (Pressure from urban sprawl can be illustrated through examples such as Sao Paolo, Mumbai, London, Tokyo, and Paris.)Sao Paolo: boom in growth close to the city center in 1930s, Brazil’s largest urban area displaced Rio Mumbai: 28.6 million people by 2025. Fastest growing mega cities. Over population leads to large amounts of pollution.London: megacity, over 10 million people. Loss of countryside in 1960 almost all building was banned in a belt of landTokyo: one half larger than any other urban areas, but its rate of population has been decreasing Economic developmentSurface mining Types of surface mining include strip mining, open-pit mining, and mountaintop removal mining.Strip mining – mining a seam of mineral by first removing a long strip of overlying soil and rock.Open-pit mining – extracting rock or minerals from the earth through their removal from an open pit or borrow. Mountaintop removal - form of coal mining that uses explosives to blast mining waste off the top of mountains. The process of surface mining includes the removal of soil and rock overlying the mineral deposit. ReservoirsA reservoir is an open-air storage area where water is collected and kept in quantity so that it may be drawn off for use. Reservoirs are used to impound water during periods of higher flows to prevent flooding. Water in reservoirs may be lost by surface evaporation and seepage through dams and surrounding soil or rocks. Reservoirs can destroy fish habitats and ecosystems and may also require the submergence of cities and towns. ................
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