DRRR

• There are different causes of landslide and sinkhole. Any of the triggers are only caused by a triggering element. A landslide can be caused by a natural or mechanical factor / human.

  
• Natural causes of landslides

  • Climate
  • Earthquakes
  • Weathering
  • Flooding
  • Volcanic Activity
  • Forest Fires
  • Gravity

  
• Human causes of landslides

  • Mining
  • Clear cutting

  
• Rainfall-Induced landslides are the most common and widespread damaging landslides in the Philippines, with an average of 20 typhoons each year due to prolonged or heavy rainfall. Most rainfall-induced landslides are shallow (less than a few meters deep), thin, and move quickly.
• Rainfall can be a cause for landslides, but soil conditions are also very critical.
• The features of precipitation occurrences, including the accumulated volume of rainfall, length and severity, and the slope of the terrain show the greatest effect on the stability of the slope and the rate of occurrence of landslides and debris.
• The precipitation-induced landslide depends on the type of land covered and the type of soil.

  
• Soil Creep Landslide


  A very slow downslope movement of particles that occurs in every slope covered with loose, weathered material

  
• Slumping Landslide


  A 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


  Happens when the slope becomes saturated with water, this then triggers a landslide of water-soaked mass of rock and soil that slides down the slope

  
• Rock Fall landslides


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

  
• Dissolution of sedimentary rocks

  Sinkholes occur when sedimentary rocks are dissolved. When these rocks are dissolved, it can either form a void of water or air.
• Underground water pumping


  Pumping water underneath the ground causes drainage to alter their flow which causes the soil to be eroded by water. Broken pipes underneath the ground can also cause internal erosion making a void underneath the ground.
• Types of Sinkholes


  • Cover Collapse Sinkhole
  • Cover Subsidence Sinkhole
  • Dissolution Sinkhole
  • Artificial Sinkhole
• Cover Collapse Sinkhole develop abruptly (over a period of hours) and thus cause catastrophic damages. They occur where the covering sediments contain a significant amount of clay.
• Cover Subsidence Sinkhole develop gradually where the covering sediments are permeable and contain sand.
• Dissolution Sinkhole occur in areas where limestone is exposed at land surface or also is covered by thin layers of soil and permeable sand.
• Artificial Sinkhole can be caused by various human activities, including groundwater pumping and construction activities.
• Sinkholes


  • Can be caused by human activities, including groundwater pumping and construction activities
  • Most common activities that result in artificial sinkholes are mining, drilling, considerable changes in weight, as well as a tremendous increase in water flow, such as a construction of an artificial pond
• Word Hunt Activity


  Find eleven causes of landslides in the pool of letters

  
• Natural Causes of Geologic Hazard

  • Causes found in the Word Hunt
• Human Causes of Geologic Hazard


  • Causes found in the Word Hunt
• Landslide


  Causes can be natural or human, effects the environment and people, caused by and intensified by certain factors

  
• Sinkhole


  Causes can be natural or human, effects the environment and people, caused by and intensified by certain factors
• Landslides and sinkholes are both geological hazards but are distinctly different

  
• Ground water pumping transfers the water upward and contributes to the formation of sinkholes
• Frequent submersion of soil in water can lead to weakened soil, formation of spaces, and shriveled soil particles
• Forest fires can make the soil water-resistant, burn resin/oil/fat in vegetation, and increase runoff, all of which can cause landslides
• Volcanic eruptions can alter minerals to clay, have volcanic gas dissolve in groundwater to weaken rock, and cause vibrations that loosen surrounding soil, all of which can trigger landslides
• Steeper slopes can trigger more massive, faster, and closer landslides due to gravity
• Liquefaction is a natural cause of landslides
• Factors affecting slope stability include soil nutrients, not wind speed, heat change, or light intensity
• Landslides can cause earthquakes, tsunamis, death, and depopulation

  
• Vibrations from blasting techniques in mining can weaken soil and contribute to landslides
• Dissolution sinkholes are caused by exposed carbonate rock, not dissolved igneous rock, narrowing wetlands, or wilted vegetation
• Cross-cutting is not a natural cause of landslides

  
• Significant increase in precipitation causes an increase in groundwater level, which can saturate soil and cause landslides
• Tectonic plate movements cause the soil covering in steep slopes to slip, leading to landslides

  
• Weathering is a natural process of rock deterioration that weakens landslide-susceptible materials

  
• Growing plants with roots that hold water can help prevent landslides in vulnerable areas