1.3A Hazards caused by earthquakes

• Earthquakes = sudden release of stored energy underground
• Types of waves:

  • P-waves
  • S-waves
  • L-waves
• P-wave:

  • primary wave
  • fastest wave
  • deal the least damage
  • vibrations caused by compressions - material movement is the same way as the wave
• S-wave:

  • secondary waves (arrive second)
  • only travel through solids
  • shear waves - move material perpendicular to the wave movement
• L-waves:

  • arrive last as they travel only on the surface
  • large amplitude and cause significant damage to buildings, include fracturing the ground surface
• Crustal fracturing = Earthquakes cause crustal fracturing within the Earth, but also buckle and fracture the ground surface

  -> 2004 Indian Ocean tsunami, rupture a fault line for up to 1000km.
• Secondary hazards:

  • liquefaction
  • landslides
• Liquefaction = when the shaking causes particles in the ground to move further apart causing them to act like a liquid rather than a solid
• landslides = the movement of material down a slope due to vibrations of the earths surface