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CAPECAPECARIBBEAN STUDIESCARIBBEAN STUDIES

IMPACTS OF GEOGRAPHICAL IMPACTS OF GEOGRAPHICAL PHENOMENAPHENOMENA

Presented byPresented byChristopher A HumberChristopher A Humber

20102010

PLATE TECTONICSPLATE TECTONICS

DEFINITION: DEFINITION: The generally fully accepted theory The generally fully accepted theory that the solid earth’s surface or crust that the solid earth’s surface or crust is divided into several segments is divided into several segments (plates) that are in relative motion.(plates) that are in relative motion.

A divergent/spreadingA divergent/spreading boundary boundary is where the is where the tectonic plates are separating. Some spreading tectonic plates are separating. Some spreading boundaries are places where the crust is sinking boundaries are places where the crust is sinking downward as it is stretched thin - like in the East downward as it is stretched thin - like in the East Rift Valley of Africa, where the Dead Sea is Rift Valley of Africa, where the Dead Sea is located. These are places where volcanic activity located. These are places where volcanic activity is at a premium because the crust is being torn is at a premium because the crust is being torn open (as in splitting and cracking, like an egg open (as in splitting and cracking, like an egg breaking open). New crust is forming when breaking open). New crust is forming when molten lava from deep down oozes out of the molten lava from deep down oozes out of the cracks where the plates are coming apart . Long cracks where the plates are coming apart . Long chains of undersea mounts (the world's longest is chains of undersea mounts (the world's longest is the mid-Atlantic Ocean Ridge) and volcanic the mid-Atlantic Ocean Ridge) and volcanic islands typically characterize these type of plate islands typically characterize these type of plate marginsmargins

The The transverse boundariestransverse boundaries are places are places where the two plates are just sliding past where the two plates are just sliding past each other, like two ships passing on the each other, like two ships passing on the water . In many of these boundaries there water . In many of these boundaries there is a lot of tension and strain where the two is a lot of tension and strain where the two plates are sliding and scraping past each plates are sliding and scraping past each other. The resulting strain from the sliding other. The resulting strain from the sliding action of the plates causes cracks in the action of the plates causes cracks in the crust called crust called faultsfaults. As the larger plates . As the larger plates move past each other some chunks of move past each other some chunks of crust and overlying rock are broken into crust and overlying rock are broken into fault blocksfault blocks. When there is a big enough . When there is a big enough movement along the cracks or faults in the movement along the cracks or faults in the earth's crust we feel it in the form of earth's crust we feel it in the form of earthquakes.earthquakes.

A A converging boundaryconverging boundary is the opposite of a is the opposite of a spreading boundary. Typically you will see spreading boundary. Typically you will see a converging boundary on a tectonic plate a converging boundary on a tectonic plate that is on the opposite side of a spreading that is on the opposite side of a spreading boundary - of course! The two plates boundary - of course! The two plates collide upon meeting and then the heavier collide upon meeting and then the heavier one will sink or subduct into the mantle one will sink or subduct into the mantle below the lighter one. This causes below the lighter one. This causes earthquakes and volcanoes to be formed. earthquakes and volcanoes to be formed. The N. American plate is converging with The N. American plate is converging with the Caribbean plate to form the L. Antilles.the Caribbean plate to form the L. Antilles.

SOIL EROSIONSOIL EROSION

The unwanted removal of soil particles The unwanted removal of soil particles from one area to another leading to from one area to another leading to negative environmental and socio-negative environmental and socio-economic consequences.economic consequences.

PROCESSES OF EROSIONPROCESSES OF EROSION

GRAVITY: Caused by mass wasting GRAVITY: Caused by mass wasting processes such as landslides and soil processes such as landslides and soil creep downslope.creep downslope.

WIND: Loose particles are dislodged WIND: Loose particles are dislodged and carried in the air being suspended.and carried in the air being suspended.

WATER: Particles are dislodged and carried WATER: Particles are dislodged and carried away by moving surface water.away by moving surface water.

Stream-bank & TunnelStream-bank & Tunnel

ICE: Moving glaciers can scrape ICE: Moving glaciers can scrape valley surfaces removing top soil.valley surfaces removing top soil.

SHORELINE: Waves; tides and SHORELINE: Waves; tides and sea-level changes can redistribute sea-level changes can redistribute

soil particles.soil particles.

ANTHROPOGENIC: Man through ANTHROPOGENIC: Man through his activities can remove soil his activities can remove soil

particles eg. excavating.particles eg. excavating.

CAUSESCAUSESNatural FactorsNatural Factors heavy rains on weak soil:heavy rains on weak soil: rain drops loosen soil rain drops loosen soil

particles and water transports them down hill. particles and water transports them down hill. vegetation depleted by drought:vegetation depleted by drought: rain drops are free to rain drops are free to

hit the soil, causing erosion during rainfall. Winds blow hit the soil, causing erosion during rainfall. Winds blow away the fine particles during droughts. away the fine particles during droughts.

steep slopes:steep slopes: gravity 'pulls harder': water flows faster; gravity 'pulls harder': water flows faster; soil creeps, slips or slumps downhill. soil creeps, slips or slumps downhill.

sudden climate changesudden climate change • rainfall:rainfall: erosion increases unexpectedly rapidly as rainstorms erosion increases unexpectedly rapidly as rainstorms

become more severe. become more severe. • drought:drought: water dries up and the soil becomes a playball of water dries up and the soil becomes a playball of

winds. Soil biota die. A sudden rain causes enormous damage. winds. Soil biota die. A sudden rain causes enormous damage. • changing winds:changing winds: areas previously sheltered, become areas previously sheltered, become

exposed. exposed.

Human-induced FactorsHuman-induced Factors change of land (deforestation):change of land (deforestation): the land the land

loses its cover, then its soil biota, porosity and loses its cover, then its soil biota, porosity and moisture. moisture.

intensive farming:intensive farming: the plough, excessive the plough, excessive fertilizers and irrigation damage the land, often fertilizers and irrigation damage the land, often permanently. permanently.

housing development:housing development: soil is bared; massive soil is bared; massive earthworks to landscape the subdivision; soil is earthworks to landscape the subdivision; soil is on the loose. on the loose.

road construction:road construction: roads are cut; massive roads are cut; massive earthworks, leaving scars behind. Not enough earthworks, leaving scars behind. Not enough attention paid to rainwater flow and attention paid to rainwater flow and maintenance of road sides. maintenance of road sides.

SOIL CONSERVATIONSOIL CONSERVATION

The process whereby measures are The process whereby measures are adopted or implemented to prevent adopted or implemented to prevent soil erosion. These measures can soil erosion. These measures can be:be:

1.1. Engineering: Altering the gradient Engineering: Altering the gradient of the land.of the land.

2.2. Agronomic: Incorporating good Agronomic: Incorporating good farming practices and vegetation.farming practices and vegetation.

3.3. Policy: Laws and regulations.Policy: Laws and regulations.

TERRACINGTERRACING

Cutting the slope into steps so as to Cutting the slope into steps so as to break the flow of run-off.break the flow of run-off.

GABION BASKETSGABION BASKETS

Using boulder-filled wire baskets to Using boulder-filled wire baskets to support unstable stream banks and support unstable stream banks and slopes.slopes.

RIP-RAPRIP-RAP

Using loose boulders to protect the Using loose boulders to protect the shoreline by wave/tidal impacts. The shoreline by wave/tidal impacts. The boulder helps to dissipate energy.boulder helps to dissipate energy.

CONTOUR PLOUGHINGCONTOUR PLOUGHING

Using ploughs Using ploughs along along the contours or hill the contours or hill slope rather than up-down or vertical. The slope rather than up-down or vertical. The former breaks the flow of run-off whilst the former breaks the flow of run-off whilst the latter produces rills to increase run-off.latter produces rills to increase run-off.

NO-TILL FARMINGNO-TILL FARMING

Also known as Also known as conservation tillageconservation tillage, is a way of , is a way of growing growing crops from year to year without from year to year without disturbing the disturbing the soil through tillage. through tillage.

In no-till farming the soil is left intact and crop In no-till farming the soil is left intact and crop residues are left in the fields. Variations of the residues are left in the fields. Variations of the conservation tillage method involve some conservation tillage method involve some working of the soil with attention paid to keeping working of the soil with attention paid to keeping soil compaction and carbon loss at a minimum. soil compaction and carbon loss at a minimum. These variations include These variations include reduced tillagereduced tillage, in , in which small strips may be plowed to allow space which small strips may be plowed to allow space for planting seeds. Other terms, such as for planting seeds. Other terms, such as incomplete tillageincomplete tillage and and minimal tillageminimal tillage may be may be used.used.

STRIP FARMINGSTRIP FARMING

Strip farmingStrip farming is a method of farming is a method of farming used when a slope is too steep or too used when a slope is too steep or too long, or when other types of farming long, or when other types of farming may not prevent soil erosion. Strip may not prevent soil erosion. Strip farming alternates strips of closely farming alternates strips of closely sown crops such as hay, wheat, or sown crops such as hay, wheat, or other small grains with strips of row other small grains with strips of row crops, such as corn, soybeans, crops, such as corn, soybeans, cotton, or sugar beets. It is also cotton, or sugar beets. It is also known as strip cropping.known as strip cropping.

WIND BREAKSWIND BREAKS

A A windbreak, orwindbreak, or shelterbeltshelterbelt, is , is usually made up of one or more rows usually made up of one or more rows of trees planted in such a manner as of trees planted in such a manner as to provide shelter from the wind and to provide shelter from the wind and to prevent soil erosion. They are to prevent soil erosion. They are commonly planted around the edges commonly planted around the edges of fields on farms.of fields on farms.

DROUGHTSDROUGHTS

A drought occurs when the average A drought occurs when the average amount of precipitation for a region amount of precipitation for a region drops far below the normal amount drops far below the normal amount resulting in adverse environmental resulting in adverse environmental and socio-economic effects.and socio-economic effects.

CARIBBEAN 1973 and mid 80sCARIBBEAN 1973 and mid 80s Bush fires eg. Approx. 50% of the Valencia/Matura forest Bush fires eg. Approx. 50% of the Valencia/Matura forest

reserve was destroyed. Loss of biota.reserve was destroyed. Loss of biota. Pipe-borne water supply is disrupted. WASA had to regulate Pipe-borne water supply is disrupted. WASA had to regulate

the normal supply.the normal supply. Agricultural production decreased. Dairy industry affected Agricultural production decreased. Dairy industry affected

by heat-stress and poor quality pastures. Farmers could not by heat-stress and poor quality pastures. Farmers could not irrigate plots.irrigate plots.

Industries suffered because of lack of water for cooling Industries suffered because of lack of water for cooling turbines etc.turbines etc.

Human resource affected leading to a loss in productivity Human resource affected leading to a loss in productivity (discomfort; associated diseases etc.)(discomfort; associated diseases etc.)

Soil erosion increased.Soil erosion increased.

NB: 1978 Drought in Brazil caused US$ 5,700 millions in NB: 1978 Drought in Brazil caused US$ 5,700 millions in damage.damage.

HURRICANESHURRICANES

IMPACTSIMPACTSSOCIALSOCIAL The power of Ivan, lost homes and possessions caused The power of Ivan, lost homes and possessions caused

emotional trauma and shock. Counseling had to be provided.emotional trauma and shock. Counseling had to be provided. 39 killed39 killed Looting created further disruption and prisoners escaped Looting created further disruption and prisoners escaped

causing a breakdown in law and order. A state of emergency causing a breakdown in law and order. A state of emergency was declared with curfew.was declared with curfew.

80-90% of houses were damaged or destroyed and up to 8,000 80-90% of houses were damaged or destroyed and up to 8,000 had to sleep in shelters.had to sleep in shelters.

There was loss of electricity and limited supply of potable water. There was loss of electricity and limited supply of potable water. Water was also contaminated. Most landline telephones were Water was also contaminated. Most landline telephones were put out of service and radio transmitters were blown down.put out of service and radio transmitters were blown down.

Roads were blocked and the airport partially destroyed and Roads were blocked and the airport partially destroyed and closed down.closed down.

The recently built national stadium was damaged.The recently built national stadium was damaged.

ECONOMICECONOMIC

Estimated damage put at US$ 815 million or 200% of GDP.Estimated damage put at US$ 815 million or 200% of GDP. Tourism sector affected. Out of 1,700 hotel rooms, only Tourism sector affected. Out of 1,700 hotel rooms, only

three remained in service. Cruise ship port damaged.three remained in service. Cruise ship port damaged. Nutmegs, the main farm export had 90% of the plantations Nutmegs, the main farm export had 90% of the plantations

destroyed.destroyed. Tax revenue was reduced .Tax revenue was reduced . Insurance premiums went up.Insurance premiums went up. In the US offshore oil platforms were destroyed reducing In the US offshore oil platforms were destroyed reducing

outputs in production.outputs in production.

EARTHQUAKES & EARTHQUAKES & VOLCANOESVOLCANOES

AREAS IN THE EASTERN CARIBBEAN WHERE EARTHQUAKES ARE COMMON

KINGSTON, JAMAICA AFTER THE 1907 EARTHQUAKE

A WRECKED CHURCH IN DOMINICA, 2004 EARTHQUAKE

SOCIAL DISPLACEMENTSOCIAL DISPLACEMENT

This occurs when a population becomes This occurs when a population becomes fragmented or separated during a natural fragmented or separated during a natural disaster due to evacuation and migration. disaster due to evacuation and migration.

Families are broken-up.Families are broken-up. Culture and traditions are lost.Culture and traditions are lost. Trauma and emotional stress occurs.Trauma and emotional stress occurs. Refugees have difficulty settling in new Refugees have difficulty settling in new

territory (jobs; new cultures etc)territory (jobs; new cultures etc)

. The 1995-2004 Soufriere volcano . The 1995-2004 Soufriere volcano disturbances in Montserrat saw the disturbances in Montserrat saw the displacement of approx. 8,000 displacement of approx. 8,000 people or 76% of the population. The people or 76% of the population. The majority of them went to Britain and majority of them went to Britain and neighboring Antiguaneighboring Antigua

CORAL REEFSCORAL REEFS

FRINGING REEF:BUCCOO REEF TOBAGO.FRINGING REEF:BUCCOO REEF TOBAGO.

BARRIER REEF: BELIZE; BAHAMASBARRIER REEF: BELIZE; BAHAMAS

BENEFITSBENEFITS

PROTECT COASTLINE: A well-developed fringing reef is a self-PROTECT COASTLINE: A well-developed fringing reef is a self-constructed, self-repairing breakwater, which protects the coastline constructed, self-repairing breakwater, which protects the coastline and beaches from erosion. Waves loose much of their erosive power and beaches from erosion. Waves loose much of their erosive power when they break on the reef. Also, much of the sand like on west when they break on the reef. Also, much of the sand like on west coast Barbados, is derived from corals which helps to protect the coast Barbados, is derived from corals which helps to protect the coastline.coastline.

FISHING INDUSTRY: Coral reefs provide a habitat for marine life, FISHING INDUSTRY: Coral reefs provide a habitat for marine life, including fish and shellfish. Species such as conch and lobster are including fish and shellfish. Species such as conch and lobster are important resources for the fishing and associated tourism industry.important resources for the fishing and associated tourism industry.

RECREATION & TOURISM:Photography; scuba diving; snorkeling etc.RECREATION & TOURISM:Photography; scuba diving; snorkeling etc.

HERITAGE: Buccoo reef, Tobago part of the island’s pride.HERITAGE: Buccoo reef, Tobago part of the island’s pride.

SCIENCE & RESEARCHSCIENCE & RESEARCH

THE ENDTHE END