Earthquake

• Earthquake Hazards


  Earthquake agents which have the potential to cause harm to vulnerable targets which can either be humans, animals or even your environment
• Effects of an earthquake


  • Primary effects
  • Secondary effects
• Primary effects

  • Permanent features an earthquake can bring out (e.g. fault scarps, surface ruptures, and offsets of natural or human-constructed objects)
• Secondary effects


  • Ground movement results to other types of destruction (e.g. landslides, tsunami, liquefaction and fire)
• Four earthquake hazards which are considered as secondary effects

  • Landslides
  • Tsunami
  • Liquefaction
  • Fires
• Landslides


  • Seismic vibration is a common triggering mechanism
  • Can have devastating effects like floods, blocking of rivers, death, and damage to land and natural resources
  • Can be prevented by reinforcing slope material, modifying the pathway for surface and underwater and by putting piles and retaining walls
• Tsunami

  • A huge sea wave triggered by a violent displacement of the ocean floor
  • Underwater earthquakes, volcanic eruptions or landslides can cause tsunami
  • As it approaches a shallow coastline, its speed decreased, but the height of the tsunami increases drastically, bringing so much damage to nearby communities
  • Can overwhelm sewage systems, destroy structures and kill people
• Liquefaction


  • Earthquake motion can turn loosely packed, water-saturated soil to liquid
  • Liquefied soil becomes less compact and ultimately lose the ability to support roads, buried pipes, and, of course, houses
  • Caused by vibration or saturation with water which causes the soil to decrease in density
  • Poses danger for it leads to unstable structures of buildings due to ground subsidence
• Fires


  • Earthquakes cause fires
  • Even moderate ground shaking can break gas and electrical lines, sever fuel lines, and overturn stoves
  • Water pipes rupture, so it would be impossible to extinguish the fire
• Methods of reducing earthquake risks

  • Effective recording and interpretation of ground motion
  • Constructing seismic hazard maps
  • Developing resistant structures
• Effective recording and interpretation of ground motion

  • Can be done by effective instrumentation in order to determine the location, strength and frequency of earthquakes
  • Assists in providing alerts and warnings especially to high-risk or vulnerable areas for preparation and emergency response
• Constructing seismic hazard maps

  • Shows the potential hazards in a given area
  • Serves as basis for disaster management information like locations for evacuation and evacuation routes
  • The anticipated intensity of ground shaking is represented by a number called the peak acceleration or the peak velocity
• Developing resistant structures


  • Able to withstand collapse by redistributing forces caused by seismic waves through shear walls
  • Developing engineered structural designs that are able to resist the forces generated by seismic waves can be achieved either by following building codes based on hazard maps or by appropriate methods of analysis
• The Philippines is prone to natural calamities
• Pushing for programs that build calamity-proof housing projects must be given importance
• Calamity-proof housing


  • Steel is usually used as frame for its ability to withstand enormous force without getting damaged
  • Steel is easy to maintain, can withstand the test of time, has high strength to weight ratio, and is eco-friendly