Tsunamis

• The shapes are relatively young in geological terms and have been deforested
• Damage caused by a landslide after an earthquake in Nepal in 2015
• The 2015 earthquake in Nepal
• Landslides played a significant role in the high number of deaths attributed to the 2015 Nepal earthquake
• The earthquake weakened the rock and sediment structure on large sections of the southern slopes of the Himalayas north of Kathmandu, the earthquake's epicentre
• Landslides and avalanches, including one on Mount Everest which killed over 20 climbers, were frequent occurrences in the immediate aftermath
• The continuous rainfall over the monsoon season (to September) continued to create slip planes for rockslides
• Large-scale mass movements continued months after the earthquake
• Tsunamis


  A series of large waves
• Tsunamis


  • They usually occur at subduction zones
  • They are caused by the displacement of large volumes of water
• Tsunami generation


  1. Submarine earthquake causes seafloor to move quickly upwards or downwards

  2. This displaces water (known as water column displacement)

  3. Waves radiate out in all directions from the epicentre of the earthquake
• The greater the movement of the seafloor


  The greater the volume of water displaced, and the bigger the wave
• Waves start very small in height but travel very fast
• As waves approach the coast

  • They lose energy and slow down due to friction with the rising seabed
  • This causes the waves to grow in height as water is backed up
• A tsunami will usually be more powerful if the epicentre is close to the coastline, or is travelling through very deep water, as it has less time to lose this energy
• The length of time between tsunami waves can vary but is usually no more than a few minutes
• What did the ground say to the earthquake? A tsunami wave is the
• As waves approach the coastline of Japan in 2011, they slow down and grow in height