geography m2 landslide
TRANSCRIPT
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Geography Module #2 Unit #2 Lesson #8
BEGINBEGIN
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
IntroductionLandslides are one of the major natural hazards in Jamaica. In this lesson you will learn about the natural and human factors that cause landslides, the damage landslides can cause and measures that are used to prevent landslides.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
ObjectivesAs a result of this lesson, you will be able to 1. Describe a landslide 2. Explain the natural and human factors that cause
landslides3. Realize that landslides are natural hazards4. Recognize an area that has been affected by
landslide5. Assess measures used to stabilize slopes6. Aware of the impact of landslides on the natural
and built environment
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
What are landslides?
Landslides are a rapid type of mass movement. During a landslide, soil, rock or both fall suddenly
under the influence of gravity.
CHECKCHECK
In Slide Show view, type your answer in the box below. Click CHECK for feedback.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
What are landslides?The material (soil/rock) that is displaced during a landslide, accumulates at the base of the slope and a scar marks the place from which material is removed.
Scar
Soil at base
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Where do landslides occur?
Landslides occur on steep slopes in mountainous or hilly areas, along the coast and in submarine environments(under the sea)
CHECKCHECK
In Slide Show view, type your answer in the box below. Click CHECK for feedback.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Natural factors that cause landslides
The force of gravity acts upon the overhang resulting in slope failure.
The river (running water) erodes (removes) material from the base of the slope, thereby over steepening the slope.
The river (running water) erodes (removes) material from the base of the slope, thereby over steepening the slope.
Landslides occur when a steep slope is undercut by running water.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Natural factors that cause landslides The erosive action of waves removes material from the base of a cliff resulting in the over steepening of the slope. The force of gravity acts upon the overhang causing slope failure/landslide
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Natural factors that cause landslides Landslides are caused by the lubricating action of water. This is common where permeable rock which allows water to collect in joints and bedding planes overlies impermeable rock such as clay. The water soaks through the permeable layer and settles on top of the clay. The surface of the clay becomes smooth and slippery over which the permeable layer easily slides.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Natural factors that cause landslides Weathered material also called regolith allows water to pass through. This means that it is permeable. The permeable regolith rests on top of an impermeable bedrock. Water collects on the surface of the bedrock creating a slippery surface over which the reoglith slides.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Natural factors that cause landslides Earthquakes can also trigger landslides. The shaking that occurs during an earthquake can cause weathered material on steep slopes to slide down hill resulting in a landslide.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Natural factors that cause landslidesClick open the link and watch the video at:http://www.youtube.com/watch?v=Vc6ouosXk0Q&feature=related
As you watch note the following:Speed of down slope movement Slope angleBedding planes and jointsSource of lubrication Where material rests and scar left
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Man-made factors that induce landslides
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The actions of man can cause landslides. In order to construct roads or railways material is removed from the base of a slope. The removal of material from the base of the slope weakens the slope making it susceptible to failure.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Man-made factors that induce landslides
The construction of buildings on slopes will add pressure which can result in slope failure.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Man-made factors that induce landslides
Changes in land use such as clearing a forest to facilitate the planting of crops or the building of houses can reduce the strength of a slope and result in slope failure.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Man-made factors that induce landslides
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Vegetation on slopes will intercept some of the rainfall thus preventing it from reaching the slope.
The vegetation will also absorb some of the moisture therefore less is available to lubricate the soil.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Impact of landslides on the built environment
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Landslides can block or cut off roads. Roads become impassable and communities are marooned.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Impact of landslides on the built environment
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Landslides can bury buildings and cause loss of life.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Impact of landslides on the natural environment
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Landslides remove valuable top soil from farmland or bury farms; crops and livestock under rock and soil.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Impact of landslides on the natural environment
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Landslides also add sediments to rivers, raising channel levels and increasing the risk of flooding in the future.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Impact of landslides on the natural environment
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Landslides can block rivers thus creating a dam. The dam may remain for a long time but when it fails can cause flooding.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Mitigation measures Retaining wallsRetaining wallsThese must be built with outlets for water. If water and soil are allowed to build up behind the wall the wall may not be strong enough to withstand the pressure and may break.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Mitigation Measures Gabion basket Gabion basket – rocks are packed against the slope and are then secured with mesh. The packed stones allow for proper drainage of the slope.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
QUIZ
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Are you ready to test yourself? There are five multiple choice items that you are
required to do. For each item, click on the letter of the correct
response and then click the button ‘NEXT QUESTION’ to continue.
Click the BEGIN QUIZ button to begin.
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
QUIZ: Question 1
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The rapid movement of rock and soil down a slope is referred to as;
A. Weathering A. Weathering
B. Regolith B. Regolith
C. Soil creep C. Soil creep
D. Landslide D. Landslide
FEEDBACKFEEDBACK
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Quiz: Feedback to Question 1
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The rapid movement of rock and soil down a slope is referred to as landslides .
NEXT NEXT QUESTIONQUESTION
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
QUIZ: Question 2
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Landslides occur in all of the following areas EXCEPT
A. On steep slopes in hilly area A. On steep slopes in hilly area
D. On sloping land under the sea D. On sloping land under the sea
C. Along the coastline with steep cliffsC. Along the coastline with steep cliffs
B. On gently sloping landB. On gently sloping land
FEEDBACKFEEDBACK
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Quiz: Feedback to Question 2
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Landslides occur in all of the following areas EXCEPT on gently sloping land.
NEXT NEXT QUESTIONQUESTION
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
QUIZ: Question 3
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Which of the following is a natural factor that contributes to landslides?
A. Building gabion basketsA. Building gabion baskets
D. Cutting a road at the base of a slopeD. Cutting a road at the base of a slope
B. Construction of houses on slopesB. Construction of houses on slopes
C. Lubricating action of rain waterC. Lubricating action of rain water
FEEDBACKFEEDBACK
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Quiz: Feedback to Question 3
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Question 3: Which of the following is a natural factor that contributes to landslides?
Answer: The lubricating action of rain water
NEXT NEXT QUESTIONQUESTION
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Quiz: Question 4
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What human activity can trigger landslides?
A. Building retaining wallsA. Building retaining walls
D. Building roads on gently sloping landD. Building roads on gently sloping land
C. Using terraces when farming on slopesC. Using terraces when farming on slopes
B. Removing vegetation from slopesB. Removing vegetation from slopes
FEEDBACKFEEDBACK
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Quiz: Feedback to Question 4
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Question 4: What human activity can trigger landslides?
Answer: Removing vegetation from slopes.
NEXT NEXT QUESTIONQUESTION
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
QUIZ: Question 5
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Landslides can result in all of the following EXCEPT
B. Blocking of roads B. Blocking of roads
D. Creating dams along rivers D. Creating dams along rivers
C. Burying houses C. Burying houses
A. Eruption of a volcanoA. Eruption of a volcano
FEEDBACKFEEDBACK
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
Quiz: Feedback to Question 5
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Landslides can result in all of the following EXCEPT eruption of a volcano.
END OF QUIZ END OF QUIZ
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OBJECTIVES
What are landslides?
Where do landslides occur?
Natural factors that cause landslides
Man-made factors that induce landslides
QUIZ
INTRODUCTION
Impact of landslides
Mitigation Measures
End of Quiz
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