DRRR

• Landslide

  Mass movement of rock, soil, and debris down a slope due to gravity

  
• Landslide


  • Downward movement of geological materials such as soil and rock

  
• Landslide triggers


  • Intense rainfall
  • Weathering of rocks
  • Ground vibrations during earthquakes
  • Volcanic activity

  
• Manmade landslide triggers


  • Construction

  
• Landslide triggering conditions


  • Steep slopes
  • Weakening of slope material
  • Weathering of rocks
  • Overloading on the slope

  
• Types of Landslides


  • Slumps
  • Debris slides and flow
  • Rockfall and topples
  • Creep
  • Mudslides

  
• Slumps


  A type of landslide where the soil is involved. They can travel short distances and vary from rapid to very rapid.

  
• Debris slides and flow

  When debris from rockfalls and slumps mix with water, they can transform into debris slide that can travel great distances. Sometimes debris slides carry logs, trees or even houses made out of light materials.

  
• Rockfall and topples


  Involved rocks, are extremely rapid and can travel great distance. They usually occur in a cliff or steep slopes where rocks basically fall out or roll over in great speed.
• Creep


  Slow, involve soil, and travel short distances. It creates soil ripples that look like miniature folds or small wave-like figures along the slopes. Usually occur on gentle to moderate slopes.
• Mudslides


  Generally involved saturated soils moving at extremely rapid velocities and travel great distance.
• Landslide materials


  • Soil
  • Rocks, soil, water
  • Rocks and dry soil
  • Soil
  • Soil, water

  
• Landslide movement


  • Slump
  • Debris slide
  • Rockfall and topple
  • Creep
  • Mudslide

  
• Landslide velocity


  • Rapid to very rapid
  • Extremely rapid
  • Extremely rapid
  • Very slow to slow
  • Extremely rapid

  
• How to protect yourself from landslide

  1. Learn your Surrounding

  2. Know your Hazards

  3. Heighten your Observation

  4. Monitor your local news

  
• Philippines Struck by Another Deadly Landslide, Days After Typhoon
• Underlying cause of the Naga, Cebu City landslide

  Heavy rains in the days since Typhoon Mangkhut had contributed to the disaster
• Mistake made by the people before the Naga, Cebu City landslide


  They returned home after the storm largely spared Cebu and other central islands, despite evacuation orders
• Actions to mitigate or lessen the disaster caused by the Naga, Cebu City landslide

  1. Ask assistance from your local government unit and community for land survey within your area

  2. Report changes on the ground such as sinking roadways to the local government unit

  3. Discuss with your community about sinkhole awareness, especially if your local community is known for occurring sinkholes. Make disaster plan for mitigating possible disaster induced by sinkholes.

  
• Sinkhole


  Depressions or openings in the ground surface as the result of a collapse in the ceiling of an underground cavity or cavern
• Sinkhole


  An area of ground that has no natural external surface drainage – when it rains, all the water stays inside the sinkhole and typically drains into the subsurface
• Sinkhole size


  Can vary from a few feet to hundreds of acres and from less than 1 to more than 100 feet deep
• Types of sinkholes


  • Dissolution sinkholes
  • Cover-subsidence sinkholes
  • Cover-collapse sinkholes
• Dissolution sinkholes


  Occur where there is little soil or vegetation over the soluble rock. Aggressive dissolution occurs where flow is focused in pre-existing openings in the rocks, such as long joints, fractures, and bending planes, or in the zone of water table fluctuations where the ground water is contact with the atmosphere. They typically develop gradually.
• Cover-subsidence sinkholes


  Tend to develop gradually where the covering sediments are permeable and contain sand.
• Cover-collapse sinkholes


  Tend to develop abruptly and cause catastrophic damages. They occur where the covering sediments contain significant amounts of clay.
• How to protect yourself from sinkholes

  1. Ask assistance from your local government unit and community for land survey within your area

  2. Report changes on the ground such as sinking roadways to the local government unit

  3. Discuss with your community about sinkhole awareness, especially if your local community is known for occurring sinkholes. Make disaster plan for mitigating possible disaster induced by sinkholes.
• Danger of landslides and sinkholes

  • Destruction of landscape and topography
  • Property damage
  • Injury and Death
  • Negative Economic effects

  
• Impending signs of landslides and sinkholes

  • As the landslide mass slowly moves down, it pushes the ground at the bottom or toe of the slope and causes it to bulge
  • Water seeping down a slope is one of the most common sources of landslides, and is manifested by water collecting or emerging at the bottom or toe of the slope
  • Tilted vertical objects like trees, post, and fences is evidence that a slope is moving
  • Downward movement of the materials near the surfaces of the slope results in the formation of tension cracks on the slope surface
  • Ground movements cause underground pipes to break
  • Ground movements causes the foundation of buildings and other structures made from concrete to break
  • Ground movements results in tilting and differential settlements in structures