Theme 2 Flashcards
2.1 An earthquake:
General facts
Nepal Gorkha Earthquake - April (+May) 2015
- 7.8 magnitude
- 300 aftershocks
- 9000 deaths
- 2200+ injuries
- Epicentre 15km underground
- Katmandu moved 3m south in 30 seconds
- May 7.3 magnitude (considered aftershock)
2.1 An earthquake: Nepal 2015
Causes & Impacts
Causes
- Plate tectonics in the Himalayas - India plate moving northwards into Eurasian plate, and underneath it
- Fault mountains - pressure builds, leads to earthquake
- Epicentre 15km underground
Short term impacts
- 9000 deaths
- 2200+ injuries
- Landslides - avalanche on Mt. Everest killing 22 people
- 3.5 million made homeless
- Villages flattened
- Ancient temples fell over, many world heritage sites
Long term impacts
- Damage to buildings
- Transport networks
- Tourism decreases
- Homelessness
- People moving to cities in search of a better life
Why was impact so high?
- economic development is low, so quality of buildings is low.
2.5 An area of tropical rainforest:
Borneo rainforest - general facts
- Indonesia + Maylsia (+ Brunei)
- Only half of Borneo’s forest cover remains today, down from 75 per cent in the mid 1980s
- Current deforestation rate of 1.3 million hectares per year
- 2020 projected to have reduced forest cover to 24%
- 82% of world known plant+animal species are found in rainforests
- 1/3 of tree species are found in rainforests
2.5 An area of tropical rainforest:
Borneo rainforest - Impacts
- Habitats of many animals have been destroyed/reduced, including endangered species such as leopard, pygmy elephant and orang-utan
- Forest fires have increased, causing ‘haze’ pollution across Borneo and into neighbouring islands (illegal practices)
- Removal of the forest cover increases soil erosion, decreasing fertility
2.5 An area of hot desert:
The Namib Desert, South West Africa - general facts
- Angola, Namibia and South Africa
- 81000 km squared
- Receives <10mm rainfall each year
2.5 An area of hot desert:
The Namib Desert, South West Africa - threat to natural environment
Off-road driving
- can cause long-lasting damage to delicate desert vegetation
- Most of damage done by vehicles of mining companies
Drop in water table
- Primarily caused by extraction of groundwater which supplies the urban areas nearby (Walvis Bay) and large uranium mine
Pastoralists
- Grazing large herds of goats and small groups of donkeys
- Livestock have overgrazed some areas and are competing for food with wild animals
Three factors to form a desert
- High pressure (little cloud)
- Cold ocean currents (usually in East)
- Mountain ranges (to create rain shadows)
Adaptations of plants to survive in a desert
- Long roots (to tap into the water deep underground)
- Short life cycles (plant or seed can remain dormant until rains come)
- Water retention - storing water in their stems, trunks or leaves
Adaptations of animals to survive in a desert
- Burrowing into the ground to avoid the sun
- Nocturnal animals sleeping during the day, sheltering to prevent dehydration
- Animals may hibernate during temperature highs and lows
Rainforest levels of vegetation
Emergent
Canopy
Under-canopy
Shrub layer
Adaptations of plants in a rainforest
Buttress roots
- Very thick, stable roots that prevent tall trees from being affected by strong winds
Lianas
- Woody vines that climb using the tall trees to reach the canopy
Drip tip leaves
- Oval leaves that come to a point to allow water to drop off easily to prevent mould from growing on it
2.3 The opportunities presented by an area or areas of coastline, the associated hazards and their management:
Unawatuna, Sri Lanka - general facts
- ‘The best beach in the world’ - tourist boom
- December 2004, Asian tsunami devastated
2.3 The opportunities presented by an area or areas of coastline, the associated hazards and their management:
Unawatuna, Sri Lanka - failed protection
Breakwater
- Caused the beach to begin realigning its shape
- Beach pushed from East to West, exposing several hotels and properties
Sea walls
- Vertical, not curved
- Reflected not deflected, beach was eroded further
++++ MORE
Impact of equatorial climate on a tropical rainforest
- Competition for sunlight, trees grow taller
- Layered structure
- High diversity/rapid speciation
- Rainforest regeneration, focused on tree gaps (due to storms/wind)
- Thin soil, not very nutritious
- Silty rivers
Equatorial climate
- Hot
- High precipitation
- high radiation
- Thunderstorms form daily
- Little seasonality
Why deforestation occurs
- Agriculture eg palm oil plantations
- Logging for wood
- New settlements to house expanding populations
- Mining - coal (Borneo), uranium (Borneo), bauxite (DR Congo) other natural resources
- Cattle ranching
- HEP dams & reservoirs
Impacts of deforestation
- Less CO2, no longer carbon sink
- Less evaporation, less rainfall, increased likelihood of drought
Desert climate - causes
Macro
- sub tropical high pressure zone STHPZ - warm wet air rises in the tropics (rainforests), drops its precipitation and dries, pushes away from the equator and sinks in the sub-tropics, causing bands of deserts to the north (Sahara, Mexico) and south (Namib, Australian) of the equator.
Regional
- Rain shadow: when air is forced up by a mountain range, causing its moisture to condense and drop as precipitation. Air is dry on the rain shadow side of the mountains, forming deserts. eg Namib/Drakensberg Mts; Atacama (Bolivia) / Andes Mts.
- Cool ocean currents: lead to cool air with limited moisture blowing on to land . eg Namib / Benguela current (S Atlantic); Sahara / Canary current (N Atlantic)
- Prevailing winds: blowing offshore - dry continental air as opposed to moist ocean air
Namib desert - causes of desert conditions
- Located in Namibia, S Africa and Angola
- 81,000 km2
- Next to the Atlantic Ocean and the cold Benguela current flowing northwards from Antarctica: limited evaporation from the sea
- Rain shadow / prevailing winds: Drakensberg Mountains to the southeast create a rain shadow: air rises over the mountains, cools, condenses and falls in the mountains, creating lush vegetation in the Drakensbergs and v little precipitation over the desert
Namib desert - adaptations
- Namib desert beetle has a hard outer skin that causes humidity from morning fogs to condense into droplets
- Beetle builds water-capturing webs
- Black-backed jackals lick humidity from stones
