Geographical Phenomena

• 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.