Report 1 Example B

Report 1 Example B - Introduction The term landslide...

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Introduction The term landslide includes a wide range of ground movement, such as rock falls, deep failure of slopes, and shallow debris flows. 1 Although gravity acting on an over steepened slope is the primary reason for a landslide, there are other contributing factors. 1 These include: erosion by rivers, glaciers, or ocean waves creating oversteepened slopes; rock and soil slopes weakened through saturation by snowmelt or heavy rains; earthquakes that create stresses that make weak slopes fail; earthquakes of magnitude 4.0 or greater; volcanic eruptions producing loose ash deposits, heavy rain, and debris flow; and excess weight from accumulating rain or snow, stockpiling of rock or ore from waste piles or man-made structures that stress weak slopes to failure. 1 Slope materials that become saturated with water may develop a debris flow or mud flow. 1 The resulting slurry of rock and mud may pick up trees, houses, and cars, thus blocking bridges and tributaries causing flooding along its path causing much damage. 1 Landslides occur in every state and U.S. territory. 1 The Appalachian Mountains, the Rocky Mountains and the Pacific Coastal Ranges and some parts of Alaska and Hawaii have severe landslide problems. 1 Any area composed of very weak or fractured materials resting on a steep slope can and will likely experience landslides. 1 Although the physical cause of many landslides cannot be removed, geologic investigations, good engineering practices, and effective enforcement of land-use management regulations can reduce landslide hazards. 1 Landslides are a serious geologic hazard common to almost every state in the United States. 1 It is estimated that in the United States, they cause in excess of $1 billion in damages and from about 25 to 50 deaths each year. 1 Globally, landslides cause 100's of billions of dollars in damages and l00's of thousands of deaths and injuries, each year. 1 The United States Geological Society (USGS) scientists continue to produce landslide susceptibility maps for many areas in the United States. 1 In every state, USGS scientists monitor streamflow, noting changes in sediment load carried by rivers and streams that may result from landslides.
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Report 1 Example B - Introduction The term landslide...

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