(DRR) L5-8 Earthquake Hazards and Risk Reduction Methods

• Earthquake 


  A sudden release of energy in the Earth's crust.
• Tectonic Plates

  • Large pieces of Earth's crust.
  • Triggers earthquakes.
• Seismograph 


  Instrument used to record and measure motion of the ground.
• Earthquake Hazards


  Earthquake agents that have potential to cause harm.
• 2 types of earthquake effects

  • Primary Effect
  • Secondary Effect
• Primary Effects of Earthquake

  • Fault scraps
  • Surface rupture
  • Offset of natural or human-made object
• Secondary Effects of Earthquake

  • Landslide
  • Tsunami
  • Fire
  • Liquefaction
• Landslide 


  Seismic vibration is most common triggering mechanism.
• Tsunami 


  Huge sea wave triggered by displacement of ocean floor.
• Liquefaction 


  Liquefied soil become less compact. Soil turns to liquid.
• Fires


  Broken gas, electrical lines, server fuel lines, and overturned stoves.
• Natural signs of an impending tsunami

  1. Feel an earthquake
  2. See ocean water disappearing from beach, bay, or river
  3. Hear an unusual roaring sound
• Potential Earthquake Hazards

  1. Ground shaking
  2. Ground ruptures or ground displacement
  3. Liquefaction
  4. Tsunami
  5. Earthquake-induced landslide
  6. Earthquake-induced subsidence
• Characteristics of Ground ruptures

  • Length - depends on the magnitude
  • Width - depends on type of faulting
• 2 Types of Ground Ruptures

  • Vertical displacement - up and down
  • Horizontal displacement - side to side
• Hazard Map


  Highlights areas that are affected by or vulnerable to a particular hazard
• Seismic Design Category 


  Helps to interpret an earthquake map.