Theme 2: The natural environment Flashcards
• An earthquake
- PRE EARTHQUAKE
- poorest country
- over 70% population under poverty line
- Caribbean and North American plates. - HUMAN TOLL
- 160,000 💀
- 1.3m initially displaced
- 300,000 injured no access to healthcare
3 INFRATRUCTURE - no building codes ➫ infrastructure demolishes - 300,000 homes damaged -hit near capital city Port-au-Prince,destroys impt gov budding
- 👶👦👧👶👦👧
- over 4000 schools damaged/destroyed = 1/4
5.CHLOREA OUTBREAK
665,000 cases
An volcano 🌋🌋🌋💀
😡 DIRECT - 57 💀
- 200 houses
- 47 bridges
😡 ASH DAMAGE
temporary prob ➫ transportation
➫ infrastructure
➫ water treatment
😡 AIR TRAVEL
2weeks+ airport shutdown ➫poor visibility
Spirit lake was destroyed along with 250km of fishing rivers
250km2 of forest was destroyed/ 10 million trees had to be replanted
No animals survived in the blast zone and many crops were destroyed by falling dust.
😡 😡 😡 COST:$1.1b 😡 😡 😡
most deadly/economic disaster
18/5/1980
List type of plate boundary
constructive ⏪ ⏩
conservative ⇨⇦
⇨ collision ⇦
destructive ⏩ ⇦
⏪ ⏩
CONSTRUCTIVE
➫ 2 plates move apart
➫ magma rises up to fill gap
➫ new crust is formed
e.g: Mid-ocean ridges
small e/vol⇨⇦
COLLISION
➫ 2 plates collide
➫neither forced under
➫fold up into range of mountains
big earthquakes
e.g Himalyas⏩ ⇦
DESTRUCTIVE
➫oceanic plate forced under continental bc
greater density
➫build up pressure melts oceanic plate ➫magma
➫ sudden releases pressure
➫big earthquakes
➫magma explodes to surface➫ eruption
e.g St helen
⇨
⇦
CONSERVATIVE
➫ plate slides past each other in
-opposite direction
-different speed
➫ friction is overcome
➫ plates slide past in sudden movement
➫ (land is neither destroyed/created)
➫ creates shockwaves
➫ big earthquakes
Features of earthquakes
focus: point inside crust where the pressure is released
epicentre: point on Earth’s surface above the focus
lists types of volcanoes
Shield
Composite
Features of volcanoes
Volcano: A crack or hole in the earth’s surface that allows magma, ash, gas or steam to escape to the surface.
Magma: Molten (melted) rock under the crust.
Lava: Molten rock on the surface of the earth.
Crater: The giant hole left by a volcanic eruption. Craters sometimes fill in with water to make crater lakes.
Magma Chamber: An underground store of magma.
Vent: A long tube or pipe that allows magma to escape to the surface.
present hazards living near volcanoes
Pyroclastic Flows - A cloud of red hot gas and ash which flows down the side of a volcano at 200km/hr
Lahars - A mixture of ash with rain or glacier melt water which forms a deadly river of mud
Lava Flow - A river of molten rock 1000C centigrade that can travel at 40mph
Ash Fall - Millions of tons of ash can bury buildings, roads etc.
Volcanic bombs - Rocks and lava the size of houses and cars can be hurled into the sky
waterfalls
1. band of hard rock overlies soft rock
2 less resistant rock are eroded faster
→forms plunge pool
3 river undercut,leaving hard overhang
4 erosion, weathering → overhang collapses
5 collapses rock as erosion tools
6 overtime, moves upstream
YOSIMITE
potholes
POTHELES
1. flowing water encounters bedload
forced over it & downcuts behind bedload
in circular motion
causing verical erosion
- currents erode river’s bed
→ create small depressions
flood plains
- wide flat valley floor
normal conditions: river stay within channel
flood: velocity increases, high discharge
→forces to deposites
2.deposition is encouraged
large sediments: close to channel as river doesn’t have 🌟
small sediments : carry further away → deposits
3.more floods = more layers of sediments
➫➫ leaving higher ridges next to river,LEVEE
Processes which operate in a drainage basin
(including interception, infiltration, throughflow,
groundwater flow, evaporation, overland flow)
wave-cut platforms
- at hige tide
water power attack cliff bottom
→⏰ wave cut notch
2.wave cut notch get bigger
→weight of rock above get bigger
→cliff cannot support its weight → fall
3.process continues,cliffs retreats
→→wave cut platform
beaches
LONGSHORE DRIFT
1. material is transported along coastline by waves
2.wave approach cost at an angle 90* bc prevailing wind
3. material is carried up by Swash
material is dragged down by Backswash
90*↓ = shortest route
4. material is moved in zigzag path
spits
LONGSHORE DRIFT
1. material is transported along coastline by waves
2.wave approach cost at an angle 90* bc prevailing wind
3. material is carried up by Swash
material is dragged down by Backswash
90*↓ = shortest route
4. material is moved in zigzag path
- develop in sudden change in shape of coastline
- longshore drift continues transport material in same direction rather than following coastline
- As strength of drift weakens away from coastline sediment is deposited -> spit
- change of wind direction ->hook
- area behind spit is sheltered from waves and the wind
- perf env for salt marshes to develop.
the conditions required for their development of coral reefs
- warm temp (>20*)
- shallow water > 60 m
- clear water x no sediments
- plentiful of oxygen suppply
- unpolluted
- calm sea
- low acidity
• The opportunities presented by a river or rivers, the associated hazards and their management
MANAGEMENT
- Aswan dam
- low levees in Sudan
- policies control development close to floodplain
Causes of flooding
URBANISATION
IMMPERMEABLE ROCK
LACK OF VEGETATION
STEEPSIDE CHANNEL
describe a composite volcano
Composite volcanoes
-made up of alternating layers of lava and ash
(other volcanoes just consist of lava).
- destructive .
-eruptions : pyroclastic flow rather than lava flow.
describe a pyroclastic flow
- mixture of hot steam, ash, rock and dust.
- A pyroclastic flow can roll down the sides of a volcano at high speeds. tempe 400°C+
distribution of coral reefs
in tropic/subtropic ocean near equator
vast majority in:
- Indo Pacific region
- Atlantic region
