4. Landslides and Sinkholes

• LANDSLIDES - movement of a mass of rock, debris, or earth down a slope ; "mass wasting" which denotes any down-slope movement of soil and rock under the direct influence of gravity.
• FACTORS THAT CAN CAUSE LANDSLIDES

  1. Geological - this type-causing landslide involves the physical characteristics of the rock and mineral composition and feature of the slope.
  2. Morphological - a slope with decreased vegetation cover due to fire or drought is highly prone to landslides
  3. Human Activity - agricultural and construction
• TYPES OF LANDSLIDES:

  1. Flow - landslide movement is marked by high speed due to the fluidity and consistency and water
  2. Topple - tumbling over of a blocked unit or units due to gravity, the added force exerted by neighboring units, and water in the fissures ; forward rotation of the slope mass about a point or axis below the center of gravity of the displaced mass
  3. Slump - sliding mass movement of materials along an arched portion of the slope
• Types of Landslides

  • Flow
  • Topple
  • Slump
  • Slide
  • Creep
  • Fall
• Flow


  Landslide movement is marked by high speed due to the fluidity and consistency and water
• Topple


  Tumbling over of a blocked unit or units due to gravity, the added force exerted by neighboring units, and water in the fissures ; forward rotation of the slope mass about a point or axis below the center of gravity of the displaced mass
• Slump


  Sliding mass movement of materials along an arched portion of the slope
• Slide


  Happens along weak portions of the slope such as a fault, joint, or a bedding plane
• Creep


  Unnoticeable gradual motion of material
• Fall


  Includes bouncing or rolling
• During


  Before, During, After?

  
• Before


  Before, During, After?

  
• After


  Before, During, After?

  
• SINKHOLE - hole in the ground caused by removal of material below the ground and either collapse or gradual subsidence of the surface into the resulting void ; forms when water dissolves surface rock
• TYPES OF SINKHOLES

  1. Dissolution Sinkhole - since a thin layer of soil or vegetation covers the limestone bedrock, rainwater finds its way into spaces within the bedrock and dissolves the rocks, gradually forming the dissolution sinkhole, aka limestone-solution sinkhole
  2. Cover-Subsidence Sinkhole - tend to develop gradually where the covering sediments are permeable and contain sand
  3. Cover-Collapse Sinkhole - occur in the soil or other loose material overlying soluble bedrock
• Sinkhole


  Signs of?