This lecture briefly describe Natural Disasters: 1997 Thredbo Landslide. Here focus on ordinary natural disasters; like; Earthquakes – those in the Ring of Fire; Tsunamis – the major one in 2004 killing more than 200, 000 people in South Asian region; Twisters in the USA and Bushfires in Australia. Natural disaster caused by: Intense rainfall or melting snow for long time; Long time ground erosion: Weakened ground structure and Sudden ground movement due to earthquakes.