earthquakes

• an earthquake is a sudden or violent movement within the earths crust followed by a series of shocks

  an earthquake happens when the earths plates move and cause the ground to shake
• the focus is where the pressure is released underground and where the energy radiates out, this is the place that causes the most damage
• the epicentre is the point directly above the centre of the earthquake on the earths surface
• shallow focus earthquakes are those where the focus is 0-70km under the earths surface
• deep focus earthquakes are 70-700km under the Earths surface

  deep focus earthquakes are generally less damaging since there is further to travel
• underwater earthquakes move the seabed which causes water to be displaced- can cause tsunami
• how deep is the focus of a deep focus earthquake

  70-700km
• earthquake waves- S waves

  some earthquakes produce s-waves (secondary waves) that violently shake the ground
• earthquake waves- p waves

  an earthquake can be produce p-waves (primary waves) when the tectonic stress energy is released

  they are the fastest but cute the least damage
• earthquake waves- l waves

  the waves that create significant damage are l-waves (love waves)

  these travel across the surface and have large amplitude
• what is the point directly above the centre of an earthquake

  epicentre
• where do l waves travel

  on the surface
• primary hazards of earthquakes

  ground shaking and crustal fracturing
• secondary hazards of earthquakes

  landslides- developing countries struggle to recover from landslides due to lack of infrastructure and resources

  liquefaction- when an earthquake compact loose sediment that are waterlogged and forces water to rise to the surface and cause damage to buildings