Geographical Phenomena

Cards (22)

  • Plate tectonics is the study of the movement of the crustal plates and landforms which results from these moments. This theory explains that the crust of the Earth is broken into 7 major and several minor plates. We call them continental and oceanic plates which move about due to convection currents in the mantle. 
  • These plates either move towards, away from or alongside each other.
  • Three types of movements can be distinguished.
    Divergent (constructive) - this is where the plates are moving away from each other
    Convergent (destructive) -plates moving towards each other, lighter plate submerges
    Transform - plate margins (conservative)
  • An earthquake is a vibration or series of vibration due to sudden movements of crustal rocks.
  • Seismograph - measures the shockwaves of an earthquake. It calculates the intensity of the earthquake on a rector scale which is measured on a scale of 1 to 10. Anything above 5 is bad.
  • Tsunami

    When earthquakes originate under the ocean, it causes a disturbance in the water which results in a tsunami. A tsunami is a gigantic wave which can cause considerable damage to coastal areas.
  • There are 3 main types of coral reefs:

    The fringent - a low lying close to the shore separated by a narrow lagoon 
    The barrier - lies parallel to the lagoon separated by a wide lagoon (East Coast of Belize)
    The atoll - circular ring-like reef usually made up of several islands which enclose a lagoon (in Bahamas and the Tuneriff islands in Belize
  • Benefits of coral reefs

    They protect coast lines from the destructive waves and storm surges as they act as a barrier to prevent beach erosion
    They provide harbors and beaches
    They are tourist attractions in terms of diving and photography which generates much needed foreign exchange for the region
    They are breeding grounds for fish and other marine life. Thus, impacting the lives of people along the coastlines and especially in the Caribbean where fishing is popular
  • The Threats to Coral Reefs

    Coastal development
    Mariners
    Silt from lands from runoff
    Fertilizer runoff from farmlands as well as oil spills destroy marine life
    Damages caused by recreation or tourism
    Anchors from boats
  • Soil conservation and we are saying to achieve this there has to be proper management of the 
    Better farming techniques and a gradually to permanent grass or forest 
  • The impact of soil erosion

    Low yells in aviculture 
    Reduction in foreign exchange earning
    Increase in import the  bill
    Increase negative balance of trade 
    Splinting up of rivers 
  • Volcanoes

    Volcanoes are openings, or vents where lava, tephra (small rocks), and steam erupt onto the Earth's surface.
  • Effects of volcanoes

    The displacement/migration of people and sometimes loss of culture
    Pollution due to contamination of water supply by ash, dirt and gasses (tepper). Poisonous gasses are released to the air and can cause respiratory problems
    Mudflows which destroy vegetation and infrastructure
    Changes in the weather patterns due to the outflow of ash which decreases the amount of sunlight reaching the earth
  • Hurricanes

    These are severe and intense storms/cyclones which derive their energy from the warm tropical waters over which they pass
  • Negative Impact of Hurricanes

    The disruption of settlements
    Flooding
    Damaged infrastructure
    Blown off roofs
    Impassable roads
    Loss of water supply and utilities
    Loss of lives by drowning as well as by missiles blown by the wind
    Pollution
    Water contamination
  • Positive Impacts of Hurricanes

    Hurricanes replenish the aquifer (water table)
    Break droughts
    Increase domestic water supply
    The cull forest from dead and decaying trees
    They generate employment in the construction industry as buildings have to be replaced and general reconstruction
  • Soil Erosion

    Soil erosion is a gradual process that occurs when the impact of water or wind detaches and removes soil particles, causing the soil to deteriora
  • There are 3 main types of erosion

    Sheet erosion - the removal of a uniform layer of soil by moving water. It is most common in sloping fields where water causes tiny particles to move downwards
    Gully erosion - the removal of soil by the action of water especially in steep areas where the water creates gullies
    Wind erosion - the removal of loose soil through the process of deflation. This occurs in areas where the land is bare and dry resulting in the particles becoming loosened and therefore, susceptible to the force of the wind
  • Drought

    Drought has long been considered the most insidious cause of human misery. It can occur in areas that normally enjoy adequate rainfall or moisture levels. No In the broadest sense, any lack of water for the normal needs of agriculture, livestock, industry or human population may be termed a drought.
  • Possible causes of drought

    Lack of supply
    Contamination of supply
    Inadequate storage of conveyor systems
    Abnormal demand
  • The main causes of drought are:

    Widespread and persistent atmospheric areas of calm called subsidence which do not cause precipitation
    The absence of rain causes disturbances caused by dry weather.
    The absence of humid air streams
  • Impacts of Droughts

    As a dry period progresses and water supplies dwindle, existing water supplies are overtaxed and finally dry up.