DRRR

• Landslide


  Massive outward and downward movement of slope-forming materials
• Landslide


  • The term is restricted to movements of rocks and soil masses
  • Initiated when a section of a hill slope is rendered too weak to support its own weight
  • Developed as a result of denudation of mountains or alteration of the surface of the ground
• Geological causes of landslides


  • Weak or sensitive materials
  • Weathered materials
  • Sheared, jointed, or fissured materials
  • Adversely oriented discontinuity
  • Contrast in permeability and/or stiffness of materials
• Morphological causes of landslides

  • Tectonic or volcanic uplift
  • Glacial rebound
  • Fluvial, wave, or glacial erosion of slope toe or lateral margins
  • Vegetation removal
  • Subterranean erosion
• Human causes of landslides

  • Deforestation
  • Irrigation
  • Water leakage from utilities
  • Mining
  • Loading of slope or its crest
• Types of landslides


  • Slides (rotational and translational)
  • Flows
  • Fall and toppling
  • Creep
  • Lateral spreads
• Creep


  Imperceptibly slow, steady, downward movement of slope-forming soil or rock caused by shear stress sufficient to produce permanent deformation, but too small to produce shear failure
• Lateral spreads


  The movement of material sideways, or laterally, when a powerful force, such as an earthquake, makes the ground move quickly, like a liquid
• Sinkhole


  A hole in the ground that forms when water dissolves surface rocks
• Types of sinkholes


  • Dissolution sinkholes
  • Cover-subsidence sinkholes
  • Cover-collapse sinkholes
  • Human-induced sinkholes
• Dissolution sinkhole


  There is little soil or vegetation over the limestone or other bedrock. Water from rain and runoff slowly trickles through crevices in the bedrock, dissolving it, gradually forming a depression
• Cover-subsidence sinkhole


  These sinkholes happen in areas where sand covers the bedrock. The sand filters down into openings in the rock, gradually causing the land surface to sink
• Cover-collapse sinkhole


  The bedrock is covered by a layer of clay. Beneath this ground cover, water dissolves an underground cavern. Ground sediments begin to erode into the cavern from the bottom until the thin layer at the surface collapses suddenly
• Human-induced sinkhole


  New sinkholes have been correlated to land-use practices, especially from groundwater pumping and from construction and development practices
• Precautionary measures for sinkholes

  • Watch for signs of water disappearing from the surface
  • Check fields before undertaking machine-related activities
  • Keep tractors and heavy machinery far enough away from the sinkhole
  • Do not allow unauthorized persons to investigate the sinkhole
  • Restrict access to the hole
  • Check emergency hotlines and inform them of the sinkhole
  • Don't get too close or go down the hole
• Signs of an impending landslide

  • Earlier landslide as an indicator
  • Tension cracks
  • Things moving
  • Water doing something different
• What to do before a landslide

  • Secure clearance from MGB on status of possible landslides
  • Prepare for evacuation
  • Maintain a list of emergency contact numbers
  • Participate in tree-planting
  • Participate in regular drills on evacuation procedure
  • Promote public awareness
• What to do during a landslide

  • Evacuate immediately if warned of an impending landslide or mudflow
  • Stay away from the path of landslide debris
  • Get out of the house as soon as possible when trembling of the ground is felt
  • Run across a slope, not downwards
• What to do after a landslide

  • Examine thoroughly the damaged parts and utilities of the house before reoccupying it
  • Stay away from the landslide area
  • Seek the advice of a geotechnical expert to evaluate landslide hazards
  • Listen to local radio or television stations for the latest emergency information
  • Help check with caution injured and trapped persons within the landslide areas and direct rescuers to their locations
• Landslides destroy everything and anything that comes in their path (roads, rail lanes, agricultural production, land area, etc.)
• Landslides can result in loss of lives (depends on the place and time of occurrence)
• Landslides can result in loss of property value
• Rotational slide: This is a slide in which the surface of rupture is curved concavely upward and the slide movement is roughly rotational about an axis that is parallel to the ground surface and transverse across the slide.
• • Translational slide: In this type of slide, the landslide mass moves along a roughly planar surface with little rotation or backward tilting.