Geography - Natural Hazards

El Nino and La Nina
1. El Nino
  1. CASE STUDY:- EL NINO 1991/92
    1. Effected 100 million people
    2. Led to Cholera epidemic in 1991 in Peru
    3. Brought worst drought in the 20th century for Africa
    4. Heavy rains and severe flooding in Peru and Chile, severe drought in Africa
  2. Weak trade winds lead to eastward flow
  3. Cold Peru current is suppressed thus fish don't migrate to the Peruvian coast - Leads to economic decline in fishing and tourism is affected by the reduction on sea birds as they have no food to eat
  4. High pressure in Africa - Anti-cyclonic condition persist
  5. Low pressure in South America brings heavy persistent rains
  6. Usually 12-18 months long
  7. Warm water that lacks nutrients moves off the east coast creating the rainfall
2. La Nina
  1. Low pressure in Africa bringing storm clouds with strong intensity
  2. Warm water pushed towards the Australian coast
  3. High pressure over South America bringing low temperatures and drought
  4. 1996 sardine and anchovy catches were much higher due to cold nutrient rich waters off the east coast of South America
  5. Very strong west trade winds with a high altitude flow being experienced in the upper atmosphere
Volcanoes
1. Conservative Boundary
  1. These create high fold mountains
  2. Two similar plates are converging with the plates being forced together thus creating a huge strain of the earths crust
  3. Gentle eruptions with runny lava
2. Constructive Boundary
  1. Volcanoes mainly at the sea
  2. Two plates diverging
  3. Gentle eruptions with runny lava - Shield Volcano
3. Destructive Plate Boundary
  1. Heavy plate sinks beneath the lighter plate. They plate is usually the oceanic plates sinking under the lighter continental plates
  2. This creates violent eruptions
  3. Strato Volcanoes
  4. CASE STUDY:- MOUNT PINATUBO1991
    1. Refer to casse study mind map
Drought
1. EFFECTS OF PROLONGED DROUGHT:-
  1. Leads to rising food prices
  2. More wildfires
  3. Rapid migration to urban areas
  4. Water shortages
  5. Human and livestock death through lack of water
2. Definition: An extended period of below average precipitation that causes water shortages
3. 4 MAIN CAUSES OF DROUGHT:-
  1. 1. High pressure know as anti-cyclones block low pressure from moving in bringing weather fronts with them
  2. 2. Warm oceans cause moist air to rise forming clouds over the ocean. If winds are too weak to blow clouds onto land then no rainfall occurs over land
  3. 3. Weather front may not bring rain in example with southern Europe once the front has gone over the UK
  4. 4. If oceans are colder then less moist air will rise, thus less clouds from which would subsequently bring rain
4. SOLUTIONS:-
  1. Reduce water usage e.g. crop irrigation and water wastage
  2. Compulsory water meters
  3. Construction of reservoirs
  4. Tax large corporations for heavy water usage
5. CASE STUDY:- EASTERN/SOUTHERN AFRICA 2002
  1. The main affect was 90% loss in the harvest in ETHIOPIA AND ERITREA
  2. Over 30 million people affected (East)
  3. Severe droughts occured in Africa; both north and south of the equator
  4. Over 20 million people affected (South)
  5. Over 20% of people in Southern Africa are HIV positive so escalated the problem as they people became vulnerable to droughts and the lack of nutrition that comes along with it
  6. Oxfam has many projects such to help in the dorught such as:-
    1. Helping people in Malawi to improve simple irrigation systems
    2. Helping people to plant an emergency winter crop
6. DROUGHT MITIGATION:-
  1. Soil and water preservation. By protecting soil it is better at absorbing percipitation
  2. Water desalinisation and water recycling reduces dependency on rain water
  3. Water conservation; In Las Vegas exerophytic plants are used outside as they use less water
Flooding
1. CASE STUDY:- PAKISTAN 2010 AND 2011
  1. 2.74 MILLION PEOPLE AFFECTED IN THE SINDH REGION
  2. 483,000 Homes destroyed in the PUNJAB region
  3. In 2010, Pakistan suffered its worst floods for 80 years
2. Human factors:-
  1. Deforestation means steep slopes have low infiltration rates thus water flows straight into rivers
  2. Nearly 70% of pakistans population work in agriculture and live close to rovers to irrigate their crops; this means they're vulnerable when the rivers flood their banks
3. Why do monsoon rains vary:-
  1. Changing ITCZ
  2. Impact of a warming atmosphere
  3. Temperatures in central Pakistan
  4. Role of Enso

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Geography - Natural Hazards

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	Created by jacobhatcher97 over 9 years ago