Disaster Readiness and risk reduction

• Geological hazards


  Large-scale, complex natural events that happen on the land
• Geological hazards


  • Earthquakes
  • Volcanic eruptions
  • Landslides
  • Sinkholes
• Earthquake


  Abrupt motion of the earth's crust as a result of its energy being suddenly released in the form of seismic waves
• Seismicity/Seismic activity


  The type, magnitude, and rate of occurrence of earthquakes in a particular area over time collectively
• Faults


  • Fractures in the crust along where movement of blocks takes place, exerting compression, tension, and shearing forces
• Stress builds up in rocks beneath the surface


  Energy in the form of seismic waves is generated and experienced as an earthquake
• Focus/Hypocenter


  The place beneath the surface from which an earthquake is initiated
• Epicenter


  The point on earth's surface that is directly above the focus
• Types of Earthquakes


  • Tectonic earthquake
  • Volcanic earthquake
  • Collapse earthquake
  • Explosive earthquake
• Earthquake Hazards


  • Ground Shaking
  • Ground Rupture
  • Liquefaction
  • Ground Subsidence
  • Tsunamis
• Liquefaction


  The process by which water-saturated sediment temporarily loses strength and behaves like a liquid
• Ground Subsidence


  The sudden sinking or gradual downward settling of the ground's surface with little or no horizontal motion
• Hazard Map


  An essential tool used to identify areas that can be readily affected by or prone to natural hazards
• Parts of a Volcano


  • Vent
  • Side Vents
  • Throat
  • Conduit
  • Magma Chamber/Magma Reservoir
  • Branch Pipes
• Classification of Volcanoes


  • Active Volcanoes
  • Dormant Volcanoes
  • Extinct Volcanoes
• Active Volcanoes


  Volcanoes that regularly erupt or known to erupt within the last 600 years as documented or reported
• Dormant Volcanoes


  Volcanoes that erupted in the last 10000 years, except that these volcanoes have not erupted for an extremely long period of time
• Dormant Volcanoes


  • Mt. Pinatubo
• Extinct Volcanoes


  Volcanoes with no record of eruptions and highly unlikely to erupt
• Extinct Volcanoes


  • Mt. Arayat
• Volcano Hazards


  • Lava flow
  • Dome growth
  • Pyroclastic flow
  • Pyroclastic surge
  • Ballistic projectiles
  • Tephra fall
  • Volcanic gases
  • Lahar
• Lava flow


  When magma reaches the surface and cascades in the form of streams from an erupting vent down the volcano's slope
• Dome growth


  Lava domes formed from viscous magma that solidified around the vent
• Pyroclastic flow


  An extremely hot mixture of rock fragments, expanding gases, and ashes with a temperature greater than 800 degrees Celsius
• Pyroclastic surge


  Similar to pyroclastic flow but with less rock fragments and more gases, making it less dense
• Ballistic projectiles


  Volcanic materials, particularly volcanic bombs and blocks bigger than 64 mm, launched high up in the air due to built-up gas pressure
• Tephra fall


  Any rock fragment or pyroclastic material ejected during a volcanic eruption
• Volcanic gases


  A mixture of gases that mainly includes water vapor, hydrogen sulfide, sulfur dioxide, carbon monoxide, hydrogen chloride, and hydrogen fluoride
• Lahar


  Also known as the mudflow or volcanic debris flow, composed of a mixture of volcanic debris and water that has the consistency of wet concrete and moves down the slope of a volcano, usually finding its ways to the rivers
• Landslide


  The bulk movement of rock, debris, or earth down a tilted land due to the gravity
• Factors Causing Landslides


  • Geological
  • Morphological
  • Human activities
  • Rainfall-induced landslides
• Geological factors


  The physical characteristics of the rock and mineral composition of the slopes (steepness and structure), including weak, jointed, fissured, or weathered material; and layers within the material having particular strength, stiffness, and permeability
• Morphological factors


  Land structure, including decreased vegetation cover due to fire or drought
• Human activities


  Deforestation, land development and construction, irrigation, mining, and water leakage from utilities
• Types of Landslides


  • Flow
  • Topple
  • Slump
  • Slide
  • Creep
  • Fall
• Flow


  Landslide movement marked by high speed due to the fluidity and consistency of the material, including debris flow, mudflow, and mudslide
• Topple


  Landslide movement characterized by the tumbling over of a blocked unit or units due to gravity, the added force exerted by neighboring units, and water in the fissures
• Slump


  Sliding mass movement of materials along an arched portion of the slope
• Slide


  Landslide movement along weak portions of the slope such as fault, joint, or bedding plane, usually parallel to the slope
• Creep


  Unnoticeable gradual motion of materials