Paper 1: Tectonic Hazards Flashcards

1
Q

crust

A

surface of rock
-made from cooler, solid rock
-split into plates

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2
Q

lithosphere

A

rigid crust found between base of the crust and top of mantle

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3
Q

mantle`

A

thickest layer of earth
-made up of semi molten rock (magma)

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4
Q

asthenosphere

A

upper part of mantle

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5
Q

inner core

A

hottest part of earth
-made of iron and nickel

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6
Q

continental crust

A

-thicker
-less dense
-less likely to be destroyed

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7
Q

oceanic

A

-thinner
-newer
-more dense
-more likely to be destroyed

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8
Q

tectonic hazards distribution

A
  • close to plate margins
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9
Q

constructive plate boundary

A
  • move apart
    -creates a gap
    -movement created by ridge push
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10
Q

ridge push

A
  • magma rises through gap
    -heats edges of plate
  • creating a raised ridge at the edge of each plate.
  • lava cools to create new crust
    -it becomes denser, gravity weighs down on the crust pushing it away from the boundary
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11
Q

Most constructive plate boundaries are found

A

at the bottom of the oceans.
- the plates move apart,
allowing magma to rise,
forming new oceanic crust. .

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12
Q

Volcano formation: constructive

A
  • gap = hot magma can rise up.
    -When magma reaches the surface it gently spills out onto the edge of the plates
    The lava spreads out and cools creating wide shield volcanoes.
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13
Q

Earthquake formation: constructive

A

As the newly created crust cools and slides away from the ridge, it can fracture or crack triggering lots of gentle earthquakes.

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14
Q

destructive plate boundary.

A

Two plates move TOWARDS each other
- plates meet, ocean plate subducts

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15
Q

Earthquake formation: destructive

A
  • ocean plate sinks = it rubs against the plate above (friction)
  • the plates gets stuck.
  • Pressure builds up until the plates suddenly unstick, the energy released creates seismic waves (an earthquake)
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16
Q

Volcano formation: destructive

A
  • ocean plate sinks into the mantle,
    the edge melts creating lots of extra magma.
  • This creates pressure to build in the mantle
  • forces the magma through cracks in the crust.
    =eruption
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17
Q

subduction zone

A

plates meet, the thinner, denser (heavier) ocean plate subducts (sinks) below the thicker continental plate,

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18
Q

destructive movement caused by

A
  • Movement is created by slab pull.
    -The sinking ocean plate is pulled further into the mantle by gravity as it is colder and denser.
    This pulls the rest of the plate with it.
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19
Q

conservative plate boundary

A

Two plates move SIDE BY SIDE
- at different speeds
- As the plates scrape past each other it creates friction,
- causing the plates to become stuck.
- Pressure builds up in the plates, until the plates jolt apart.
- This releases seismic waves
-no volcanoes

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20
Q

Earthquakes focus

A
  • The place in the crust where the plates jolt apart and release seismic waves
  • this is where the earthquake begins.
  • can be deep within the crust or shallow,
21
Q

Earthquakes

A
  • As the seismic waves travel through the crust,
  • away from the focus, = they lose energy.
    These waves make the ground shake
22
Q

Earthquakes epicentre

A
  • directly above the focus on the ground’s surface.
  • The seismic waves reach the surface first at the epicentre,
  • ground shakes most violently here + the earthquake will be strongest.
23
Q

Richeter scale

A

The magnitude or strength of an earthquake is measured
The higher number on the Richter Scale, the higher the magnitude (strength).

24
Q

primary impacts

A

occur immediately

25
Q

secondary impacts

A

occur from hrs to days after initial earthquake
-follows primary impact

26
Q

Tectonic hazards - primary impacts

A
  • buildings collapse
  • transport/communication lines disrupted
  • gas/water pipes burst
  • landslides
  • animals flee
27
Q

Tectonic hazards - secondary impacts

A
  • tsunamis
  • businesses lose income
  • waterborne disease spread
    -gov struggles with debt
  • homelessness
  • unemployment = GNI lost
28
Q

Immediate responses to natural hazards

A
  • emergency shelters
  • emergency services
  • emergency food/water distributed
  • repairs to sanitation
29
Q

Long term responses to natural hazards

A
  • roads are reconstructed
  • buildings are repaired
    -rebuilt to be safer
30
Q

Nepal Earthquake impacts

A
  • over 8000 ppl died
  • 26 000 injured
  • water tanks destroyed (infrastructure)
  • homes lacked support so many collapsed
  • 3.5 mill ppl made homeless
  • no electricity
    -ppl couldn’t be reached = hospitals fell
    -tourism = collapsed as safety risks
31
Q

Earthquake case study - NZ

A
  • 185 deaths
  • sewage piped damaged
  • 170 000 homes ruined
    -many relied on emergency services
  • tourism lost
32
Q

Earthquake case study - Nepal’s immediate response

A
  • Red cross sheltered 225 000 ppl
  • water engineers helped build emergency toilets in rural
  • 90% of army delivered aid on foot
  • humanitarian aid offered
33
Q

Earthquake case study - Nepal’s long term response

A
  • 13 000 ppl displaced
  • temporary camps
  • rebuild schools
  • housing reconstruction program to rebuild homes
    -major repairs made
34
Q

Earthquake case study - NZ immediate response

A
  • emergency services sent out (helicopters)
  • shelters opened
  • 7 mil international aid
  • red cross supplied workers
  • 30 000 residents given chemical toilets
  • clean water restored in 2 days
35
Q

Earthquake case study - NZ long term response

A
  • temporary housing
  • gov 1 bil insurance claims
  • gov funded construction of 10 000 homes to replace
  • roads rebuilt
  • rebuild Christchurch safer design
36
Q

prediction

A
  • using monitoring make educated guesses for hazards
  • harder for earthquakes
37
Q

planning

A

having preparations in advance of hazard

38
Q

protection

A
  • actions taken in advance to reduce impact of hazards
    -build safer structures
39
Q

Volcanic eruptions: prediction

A
  • satellites monitor change in volcano shape
  • seismometers to detect earthquake before
  • heat sensors = change in temp
40
Q

Volcanic eruptions: planning

A
  • evacuation plan
  • exclusion zones
  • education of public
41
Q

Volcanic eruptions: protection

A
  • keep skin covered
    -windows closed
    -
42
Q

Earthquakes: prediction

A

-seismologists = measure radon gas in groundwater as it escapes from cracks in crust
- measure tremors = seismometers
- locations/time are mapped to spot patterns
- GPS on phones
-detect movement further away before
- animals change in behaviour

43
Q

Earthquakes: planning

A

-furniture fastened
- turn off main gas supply
- prepare supplies
- evacuation centres
- practice drills
-red cross + safety checklist to help plan

44
Q

Earthquakes: protection

A

-design buildings = expensive
-strengthen rds
- hard to adapt building
- resistant buildings after need to be repaired/rebuilt

45
Q

Living near to volcanoes - pros

A
  • weathered lava = nutrient rich soil for crops
  • geothermal energy
  • magma contains minerals
  • basalt in construction
  • attract tourists
46
Q

Living near to volcanoes - cons

A
  • pyroclastic flow (fast flowing) = kills anything in its path
  • tsunamis = flooding
  • buildings destroyed = loss of income
  • family live there
  • ash affects breathing
  • ash covers land
    -kill ppl + damage property
47
Q

Living near to Earthquakes - pros

A
  • ppl can feel safe = properly built buildings
  • offer jobs
  • coastal areas = ports
48
Q

Living near to Earthquakes - cons

A
  • damage to infrastructure
    -deaths
  • homes ruined
  • land slides
    -tsunamis
  • disease from polluted water
  • destruction of business