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• Landslide


  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
• If rain or any source of water frequently flows down a sloping area, the gravitational descent of loosened soil makes it possible for landslide to occur

  
• Structures built on steep-slope mountains

  • Have a high vulnerability to landslide hazards especially during heavy rains
  • Areas with steep slope, dense population and denuded terrain are distinguished by a high susceptibility to rainfall-induced landslide hazards

  
• Long or regular rain may saturate the topsoil and the bedrock, weakening the soil base of buildings or structures
• Without plants and trees whose roots can absorb water and hold the soil together, subsequent rain water can continue to loosen up the soil that anchors the buildings
• A heavy downpour of rain can quickly destroy these buildings and communities, giving way to landslides, mudslides, or mudflows
• Types of Landslide


  • Soil Creep
  • Slumping
  • Debris Flow
  • Rock Fall

  
• 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 the rainfall seeps underneath the soil through the cracks and fissures

  2. As water passes through these cracks and fissures, it erodes the soil and forms a conduit system

  3. These underground water systems increase in size as the soil is carried by the water through internal erosion

  4. This can either form a void filled with air with an underground drainage

  5. If the void is clogged with clay, then it forms a depression which then accumulates water and forms a pond

  6. Otherwise it forms a hole once the cover collapses into the void which can be either filled with air or water
• Types of Sinkholes


  • Cover Collapse Sinkhole
  • Cover Subsidence Sinkhole
  • Dissolution Sinkhole
  • Artificial Sinkhole
• The Philippines being located in the Southeast Asia is considered very vulnerable to natural hazards and disasters, which include typhoons, earthquakes, floods, volcanic eruptions, landslides, and fires that affect the country and its inhabitants

  
• Surrounding the Pacific Ocean basin is a circular arm of active volcanoes known as the "Pacific Ring of Fire" in which most of the volcanoes in the Philippines are part of
• Continental plate activities around this area result to volcanic eruptions and tsunamis in the country
• Hydrometeorological hazards


  Processes or phenomena of atmospheric, hydrological or oceanographic nature that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage
• Hydrometeorological hazards


  • Typhoon
  • Thunderstorm
  • Flood
  • Flashflood
  • Storm Surge
  • El Niño
  • La Niña

  
• Hydrometeorological conditions lead to other hazards such as landslides, fires, plagues, epidemics and in transport and dispersal of toxic substances and volcanic eruption material
• Tropical cyclone


  An intense circular storm that originates over warm tropical oceans and is characterized by low atmospheric pressure, high winds, and heavy rain
• PAGASA stated that weather forecast is a scientific estimate of future weather condition, wherein a weather condition is a state of the atmosphere at a given time expressed in terms of the most significant variables
• In the Philippines, cloudiness, rainfall and wind are the weather parameters with significant variation, and therefore of interest to the forecast users

  
• How a weather forecast is made

  1. Observation

  2. Collection and Transmission of Weather Data

  3. Plotting of Weather Data

  4. Analysis of Weather Maps, Satellite and Radar Imageries and Other Data

  5. Formulation of the Forecast
• Thunderstorm


  A powerful, short-lived weather disturbance, almost always associated with lightning, thunder, dense clouds, heavy rain or hail, and fast, roaring winds

  
• Thunderstorm formation stages


  1. Cumulus Stage

  2. Mature Stage

  3. Dissipating Stage
• Flood


  A high-water stage in which water overflows its natural or artificial banks onto normally dry land, such as a river inundating its floodplain
• Types of floods


  • Inland flooding
  • Flash floods
  • River flooding
  • Coastal flooding
  • Urban flooding
• Storm surge


  Irregular sea-level rise during tropical cyclone or "bagyo" where powerful winds force the ocean water over the coastal low-lying areas, which can lead to flooding

  
• El Niño


  Large-scale ocean-atmosphere climate interaction linked to a periodic warming in sea surface temperatures across the central and east-central Equatorial Pacific
• La Niña


  Periods of below-average sea surface temperatures across the east-central Equatorial Pacific
• El Niño effects health such as diseases related to water scarcity or shortage like diarrhea and skin diseases; Red Tide Blooms also known as Paralytic shellfish poisoning and disorders associated with high temperatures: heat cramps, heat exhaustion, exertional heat injury and heat stroke
• La Niña effects health through disease related to contaminated water due to flooding, such as acute gastroenteritis, typhoid fever, cholera and hepatitis A; disease related to wading in floodwaters contaminated with urine of infected animals, such as leptospirosis; disease brought by mosquitoes, such as dengue and malaria; accidents and injuries such as contusions, lacerations, fractures, electrocution
• Fire

  The rapid oxidation of a material in the exothermal chemical process of combustion, releasing heat, light, and various reaction products
• Landslide


  Ground movement on a sloping terrain
• Landslide


  • Does not happen on flat ground because of the angle on the ground, gravity induces the land to move downward
  • Aggravated by rain because water is a natural agent for erosion
  • If rain or any source of water frequently flows down a sloping area, the gravitational descent of loosened soil makes it possible for landslide to occur
• Structures built on steep-slope mountains

  • Have a high vulnerability to landslide hazards especially during heavy rains
  • Areas with steep slope, dense population and denuded terrain are distinguished by a high susceptibility to rainfall-induced landslide hazards
• Landslides


  • Long or regular rain may saturate the topsoil and the bedrock, weakening the soil base of buildings or structures
  • Without plants and trees whose roots can absorb water and hold the soil together, subsequent rain water can continue to loosen up the soil that anchors the buildings
  • A heavy downpour of rain can quickly destroy these buildings and communities, giving way to landslides, mudslides, or mudflows
• Types of Landslide


  • Soil Creep
  • Slumping
  • Debris Flow
  • Rock Fall

  
• Sinkhole


  Topographic depression created when groundwater dissolves the underlying limestone bedrock