DRRR Q4

• Landslide is the downward ground movement on a sloping terrain caused by gravity
• Landslide


  Also known as landslip
• Landslide


  • Caused by gravity
  • Occurs on sloping terrain
• Water is a natural agent of erosion which flows and loosens the soil
• Debris flow


  Landslide of water-saturated mass of rock, earth, and debris
• Rock fall


  Sudden slide of rocks downslope
• characterized by short distance movement down a slope, sliding along concave-upward or planar surface
• Soil creep


  Very slow movement of soil which is hardly noticeable
• Conditions for a landslide to occur include bare vegetation, heavy rain, and inclined location
• Sinkhole


  Depression in the ground that resulted from the collapse of the surface layer of the soil
• Sinkhole


  • Requires soluble rock like limestone
  • Can develop abruptly or gradually
• Artificial sinkhole


  Primarily caused by human activities like groundwater pumping
• Cover collapse sinkhole


  Develops abruptly and causes catastrophic damage
• Cover subsidence sinkhole


  Develops gradually where the covering sediments are permeable and contain sand
• Dissolution sinkhole


  Occurs in areas where limestone is exposed at land surface
• Geological hazards are natural phenomena that cause major problems around the world
• The expansion and development of cities has led to an increase in impact and damage due to geological hazards
• Most of the geological hazards are related to natural conditions, although some may be due to human activities
• Landslides


  Ground movement on a sloping terrain
• Landslides do not happen on flat ground because of the angle on the ground, gravity induces the land to move downward
• Landslides are aggravated by rain because water is a natural agent for erosion
• Structures built on steep-slope mountains have a high vulnerability to landslide hazards especially during heavy rains
• Areas with high susceptibility to rainfall-induced landslide hazards


  • Steep slope
  • Dense population
  • Denuded terrain
• Soil Creep Landslide


  Slow downslope movement of particles that occurs in every slope covered with loose, weathered material
• Slumping Landslide


  Downward movement of rock debris, usually the consequence of removal of buttressing earth at the foot of a slope of unconsolidated material
• Debris Flow Landslide


  Landslide of water-soaked mass of rock and soil that slides down the slope when the slope becomes saturated with water
• Rock Fall Landslide


  Sudden slides caused by heavy rain where the rock on the slope loosens and then slides down the slope
• Sinkhole


  Topographic depression created when groundwater dissolves the underlying limestone bedrock
• Sinkholes occur in areas where the soil foundation is made of soft minerals and rocks such as limestone, salt beds, or any acidic rocks
• The depth of sinkholes ranges from a couple of meters to several mile deep
• How sinkholes occur


  1. Water from rainfall seeps underneath the soil through cracks and fissures

  2. Water erodes the soil and forms a conduit system

  3. Void forms either filled with air with an underground drainage or filled with clay forming a depression
• Types of Sinkholes


  • Cover Collapse Sinkhole
  • Cover Subsidence Sinkhole
  • Dissolution Sinkhole
  • Artificial Sinkhole
• Cover Collapse Sinkhole


  Develops suddenly (over an hour period) thus, causing catastrophic damage
• Cover Subsidence Sinkhole


  Gradually grows where the sediment covers are permeable and contain sand
• Dissolution Sinkhole


  Occurs in areas where calcareous is exposed on the ground or where thin layers of soil and permeable sand are also covered
• Artificial Sinkhole


  Caused by various human activities, including groundwater pumping and building
• Depressions on the ground that resulted from the collapse of the surface layer of the soil is called a sinkhole
• Water is a natural agent of erosion
• Landslides that have hardly noticeable damage due to slow movement are soil creep
• Floor plan of your household and location of possible exit and entry points


  Indicate blocked exits