P1 - Natural hazards

• Natural Hazard


  A natural process which can cause death, injury, disruption to humans or destroy property and possessions
• Natural Disaster


  A natural hazard that has already happened
• Types of natural hazards

  • Geological hazards
  • Meteorological hazards
• What are geological hazards caused by?

  • Caused by the land and tectonic processes
• Examples of geological hazards

  • Volcanoes
  • Earthquakes
  • Landslides
• What are meteorological hazardscaused by?

  • Caused by weather and climate
• Examples of meteorological hazards

  • Tropical storms
• Factors affecting hazard risk

  • Human factors: Population size, Income level, Ability to cope with extreme events
  • Natural factors: Type of hazard, Frequency and magnitude of hazard, Physical geography
• Effects of natural hazards

  • Primary effects: Building/road destruction, Deaths/injuries, Crop/water damage
  • Secondary effects: Triggering other hazards, Blocked emergency aid, Disease spread, Economic weakening
• Responses to natural hazards

  • Immediate: Evacuation, Treatment, Rescue, Temporary supplies
  • Long-term: Repair, Forecasting, Monitoring, Evacuation plans, Tourism promotion
• Crust


  The outer layer of the Earth
• What are tectonic plate?

  Slices of the Earth's crust
• What can land do between tectonic plates (plate margins)?

  Land can move towards each other, away from each other, or side by side
• what can be formed at plate margins?

  Mountains or volcanoes can be formed due to heat and pressure
• Tectonic plates


  Random jagged shapes that the Earth's outer layer (crust) is divided into
• Plate margins/boundaries


  Where the tectonic plates meet
• Types of plate margins

  • Destructive
  • Constructive
  • Conservative
• Destructive plate margins


  • Plates collide towards each other
• Constructive plate margins


  • Plates pull apart
• Conservative plate margins


  • Plates move side by side in different directions or at different speeds
• Formation of destructive volcanoes

  1. Oceanic and continental plates collide

  2. Denser oceanic plate sinks/subducts beneath continental plate

  3. Heat and pressure melts oceanic plate into magma

  4. Magma rises back up through cracks in crust (vents)

  5. Forms destructive/composite volcanoes
• Formation of constructive volcanoes

  1. Plates pull apart

  2. Gap is formed

  3. Magma rises up and fills the gap

  4. Forms shield volcano
• Tectonic plates


  Random shapes that the Earth's outer layer (the crust) is divided into
• Plate margins/boundaries


  Where the tectonic plates meet
• Tectonic plates get stuck

  When they finally move, they release a lot of energy in the form of seismic waves, causing an earthquake
• Focus


  The point in the Earth where the earthquake starts, normally in the mantle
• Epicenter


  The point directly above the focus on the Earth's surface
• Seismic waves


  Vibrations from the earthquake, strongest near the epicenter and weakest further away
• Moment magnitude scale


  Measures earthquakes from 1 to 10
• Earthquake magnitude ≤ 6


  Slight damage to buildings
• Earthquake magnitude ≥ 7


  Major damage and death
• Tropical storms


  Low pressure weather systems with intense rainfall and winds
• Low pressure

  warm air rises
• Hurricane, typhoon, and cyclone


  All the exact same thing, just named differently dependent on the location they were formed
• Conditions needed for a tropical storm to form

  • It must be between 5 and 30 degrees north and south of the equator
  • The sea temperatures must be at a minimum of 27 degrees celsius
  • The wind shear which is the difference in wind speed must be low
• How tropical storms develop

  1. Warm surface water evaporates, rises and condenses into clouds, releasing energy to fuel the storm

  2. Rising air creates low pressure, increasing surface winds due to the Coriolis force

  3. As the storm moves over the ocean, the energy from the warm water supply strengthens the storm
• Tropical storm features and structures

  • The center of the storm is called the eye, with very low pressure, light winds, no clouds, no rain, and high temperature
  • The eye is surrounded by the eye wall, with spiraling rising air, very strong winds, storm clouds, and torrential rain
  • Towards the outer skirts of the storm, the wind speeds fall, the clouds become smaller and more scattered, and the rain becomes less intensive as the temperature increases
• How climate change may affect tropical storms

  • Oceans will stay at 27 degrees celsius or higher for longer each year, allowing more time for storms to form
  • More of the world's oceans could be above 27 degrees celsius, meaning tropical storms may form in areas that haven't experienced or prepared for them before
  • Higher sea surface temperatures are likely to result in more evaporation, increased cloud formation, and more energy released, making storms more powerful
• Ways to reduce the effect of tropical storms

  • Prediction and monitoring
  • Planning
  • Protection
• Prediction and monitoring


  Storms can be monitored using radar and satellites, and predicted where and when they will happen