Earthquakes

• Earthquake


  A sudden releases of energy that generate seismic waves

  -energy spreads form the focus, reaching the surface at the epicentre then spreading horizontally
• Underground waves


  P-waves= primary waves, back and forth (slinky)

  travel through solid and liquid parts of earth

  travel faster

  S-waves= secondary waves, up and down

  only travel through solid

  travel slower
• Shallow earthquake


  More destructive

  -energy has no time to dissipate
• Deep earthquake


  Less destructive

  -energy is lost along its way to the surface
• Richter Scale


  A scale that rates an earthquake's magnitude based on the size of its seismic waves.

  1-3, isn't really felt

  4-5, can be felt, causes damage to property

  6, medium strength, death and damage

  7,serious (1time a month)

  8,very strong (1time a year)

  9,widespread damage and death (1-3times every 100 years)
• Surface waves


  Rayleigh waves

  -travel through the crust, up and down, side to side

  Love waves

  -travel though the crust, side to side and spirals
• Liquefaction


  water, from the water table, risen by the shaking ground

  making ground unstable