Geology Mass Movements Overview
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Questions and Answers

What is the primary characteristic of creep in mass movements?

  • Triggered only by earthquakes
  • Liquid-like flow of mud
  • Very slow downward movement of soil (correct)
  • Fast descent of rock and debris
  • How do mudflows differ from earth flows?

  • Earth flows are always triggered by earthquakes
  • Earth flows are completely dry materials
  • Mudflows occur only in volcanic regions
  • Mudflows are faster and consist of mud and water (correct)
  • What distinguishes a lahar from other types of mudflows?

  • They occur in volcanic areas with melting snow (correct)
  • They are the slowest type of mudflow
  • They are only found in arid regions
  • They are always triggered by landslides
  • Which scenario best describes a landslide?

    <p>A rapid movement of a soil block down a slope</p> Signup and view all the answers

    What factor significantly contributes to the occurrence of landslides?

    <p>Full saturation of soils and bedrock with water</p> Signup and view all the answers

    In a rockslide, what typically triggers the movement?

    <p>Earthquakes</p> Signup and view all the answers

    Which mass movement is characterized by very slow movement of soil due to freeze-thaw cycles?

    <p>Creep</p> Signup and view all the answers

    Which of the following is NOT a factor in triggering mudflows?

    <p>Stable soil conditions</p> Signup and view all the answers

    What commonly contributes to rockfalls occurring on high cliffs?

    <p>Physical weathering processes or plant growth</p> Signup and view all the answers

    Which factor most significantly increases the risk of mass movements in built environments?

    <p>Construction of buildings and roads</p> Signup and view all the answers

    What is the most effective way to mitigate risks associated with mass movements?

    <p>Educating people about the issues of steep slopes</p> Signup and view all the answers

    Where do rockfalls most commonly occur?

    <p>On high cliffs and steep road cuts</p> Signup and view all the answers

    Which of the following is a consequence of mass movements for people?

    <p>Potential damage to structures and loss of life</p> Signup and view all the answers

    What is mass movement primarily caused by?

    <p>Gravitational force</p> Signup and view all the answers

    Which of the following is not a factor affecting slope stability?

    <p>Wind speed</p> Signup and view all the answers

    Which trigger is most likely to cause rapid mass wasting?

    <p>Earthquakes</p> Signup and view all the answers

    What is the definition of creep in terms of mass movement?

    <p>A slow, steady movement of materials downhill</p> Signup and view all the answers

    How can one identify that creep has occurred?

    <p>By observing changes in object positions</p> Signup and view all the answers

    Which of the following activities can lead to the oversteepening of slopes?

    <p>Building roads at the foot of a slope</p> Signup and view all the answers

    What role does vegetation play in slope stability?

    <p>It helps to stabilize the slope</p> Signup and view all the answers

    Which type of mass movement is characterized by a sudden and rapid descent of materials down a slope?

    <p>Landslide</p> Signup and view all the answers

    What is required for mass movement to occur in terms of surface interactions?

    <p>A low-friction surface</p> Signup and view all the answers

    What characterizes a slump in mass movements?

    <p>The mass moves along a curved surface</p> Signup and view all the answers

    What type of mass movement is specifically associated with heavy snow and slippery conditions?

    <p>Avalanches</p> Signup and view all the answers

    Which of the following factors can trigger mass movements such as slides and slumps?

    <p>Earthquakes</p> Signup and view all the answers

    Which statement is true about the material movement in a slump?

    <p>Material moves downhill and slightly inward at the top</p> Signup and view all the answers

    What is a key factor differentiating an avalanche from other types of mass movement?

    <p>The involvement of snow on an icy crust</p> Signup and view all the answers

    What causes rock mass movement in general?

    <p>The absence of any holding force</p> Signup and view all the answers

    Which type of slide occurs in areas with substantial snow accumulation?

    <p>Avalanche</p> Signup and view all the answers

    Study Notes

    Mass Movements

    • The downslope movement of soil and weathered rock resulting from the force of gravity is called mass movement.
    • Almost all of Earth's surface undergoes some degree of mass movement.

    Factors Affecting Slope Stability

    • Type of earth material
    • Slope angle and Topography
    • Climate
    • Vegetation
    • Water
    • Time

    Triggers for Rapid Mass Wasting

    • Rain
    • Oversteepening
      • Cutting at the foot of slope
      • Piling on the head of slope
    • Deforesting/ Devegetation
    • Earthquakes

    Types of Mass Movements

    • Creep: The slow, steady, downhill flow of loose, weathered Earth materials, especially soils, is called creep.
    • Flows
      • Earth flows are moderately slow movements of soils, whereas mudflows are swiftly moving mixtures of mud and water.
      • Mudflows can be triggered by earthquakes or vibrations.
      • Lahars are mudflows that occur in volcanic regions where the heat from a volcano melts snow on nearby slopes that have fine sediment and little vegetation.
    • Slides
      • A rapid, downslope movement of Earth materials that occurs when a relatively thin block of soil, rock, and debris separates from the underlying bedrock is called a landslide.
      • Landslides are common on steep slopes, especially when soils and weathered bedrock are fully saturated by water.
      • A rockslide is a type of landslide that occurs when a sheet of rock moves downhill on a sliding surface.
      • Rockslides are often triggered by earthquakes.
      • A slump results when the mass of material in a landslide moves along a curved surface.
      • Landslides that occur in mountainous areas with thick accumulations of snow are called avalanches.
      • Avalanches occur when snow that falls on an icy crust builds up, becomes heavy, slips off, and slides downslope.
    • Rockfalls
      • On high cliffs, rocks that are loosened by physical weathering processes or by plant growth can break up and fall directly downward.
      • Rockfalls commonly occur at high elevations, in steep road cuts, and on rocky shorelines.

    Mass Movements Affect People

    • Human activities such as construction of buildings, roads, and other structures can make slopes unstable, contributing to the factors that cause mass movements.
    • The best way to reduce the number of disasters related to mass movements is to educate people about the problems of building on steep slopes.

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    Description

    Explore the dynamics of mass movements including factors affecting slope stability and triggers for rapid mass wasting. This quiz covers types of mass movements such as creep, flows, and mudflows, emphasizing their causes and characteristics.

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