all of tectonics Flashcards

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1
Q

What is response?

A

what happens after an event: evacuation, immediate assistance and asses damage (by charity, services and insurers)

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2
Q

Where do most earthquakes and volcanoes occur?

A

near plate boundaries

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3
Q

What is a divergent plate boundary?

A

cause effusive basaltic eruptions and rare shallow earthquakes

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4
Q

What is an example of a divergent plate boundary?

A

mid-atlantic ridge - Iceland

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5
Q

What is a convergent plate boundary?

A

cause violent andesitic eruptions and shallow, deep powerful earthquakes, volcanic cones, ocean trenches and mountains

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6
Q

What is an example of a convergent plate boundary?

A

Japan - Pacific plate moving NW under Okhotsk plate

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7
Q

What is a conservative plate boundary?

A

Cause powerful shallow earthquakes and diverted rivers along faults

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8
Q

What is an example of a conservative plate boundary?

A

San Andreas fault

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9
Q

What are infra-plate earthquakes?

A

Caused by solid crust cracking over millions of years and primary collision at a plate boundary

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10
Q

What are infra-plate volcanoes?

A

Caused by hot spots from molten upwelling or from mantle plume under crust

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11
Q

What are convection currents?

A

Caused by heat radiating outwards from core that occur due to mantle behaving like a viscous liquid

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12
Q

What is slab pull?

A

When denser oceanic plates are subducted at cold downwellings by gravity

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13
Q

What is ridge push?

A

When magma rises at constructive margin and pushes the plates apart

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14
Q

What is paleomagnetism?

A

Movement of plates apart identified by magnetic pattern caused by magnetic field reverse (every 4 million years). Mid-oceanic ridge contains iron that lines itself parallel to magnetic field and ‘sets’ after it cools, permanently marking magnetic field

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15
Q

What is the activity at divergent boundaries?

A

shallow, low magnitude earthquakes and effusive basaltic eruptions

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16
Q

What is created at divergent boundaries?

A

Rift valley, volcanic isle and transform faults

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17
Q

What is the activity at convergent boundaries?

A

shallow to 700km, high magnitude earthquakes (ocean-ocean plates)/ moderate magnitude (ocean-continent), explosive eruptions

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18
Q

What is created at convergent boundaries?

A

ocean trench, fold mountains (ocean-cont’) or volcanic isle and ocean trench (ocean-ocean)

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19
Q

What is the activity at transform/conservative boundaries?

A

shallow, moderate magnitude earthquakes with usually no volcanic activity

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20
Q

What is created at transform/conservative boundaries?

A

ridges and scars on the surface

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21
Q

What is the activity at collision boundaries?

A

shallow to middle, moderate magnitude earthquakes with usually no volcanic activity

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22
Q

What is created at collision boundaries?

A

plateaus and fold mountains (Himalayas)

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23
Q

What are factors that affect the magnitude of an earthquake?

A
  • seismic gap
  • depth of focus
  • types of movement
24
Q

What are primary waves?

A

Arrives first and fast, moves through rock and fluids whilst pushing and pulling (compresses) in travel

25
Q

What are secondary waves?

A

Arrives second and slower than P waves, only move through rock in up and down movement

26
Q

What are love waves?

A

Arrives last but moves fastest (only through crust surface), most damaging

27
Q

What is liquefaction?

A

shaking sorts sediment that makes it act as a fluid

28
Q

What are secondary hazards of earthquakes?

A
  • liquefaction
  • landslides
  • tsunamis
29
Q

What is a landslide?

A

mass material moves downslope

30
Q

What is a tsunami?

A

water column displacement by plate thrust/volcano

31
Q

What are volcanic primary hazards?

A
  • lava flows
  • gas emissions
  • ash
  • pyroclastic flows
32
Q

What are volcanic secondary hazards?

A
  • lahars
  • jokulhaups
33
Q

What are lahars?

A

mudflows

34
Q

What are jokulhlaups?

A

meltwater floods

35
Q

What is basaltic lava?

A

Hottest (1000-1200C), low silica/gas content, low viscosity (runny), gentle/effusive

36
Q

What is andesitic lava?

A

Medium heat (800-1000C), intermediate silica/gas content, medium viscosity, violent

37
Q

What is a hazard?

A

tectonic event with potential to threaten life and property

38
Q

What is a disaster?

A

when a hazard causes significant impact

39
Q

What is vulnerability?

A

ability to anticipate, cope, resist and recover

40
Q

What is resilience?

A

ability of a community to resist the impacts of a hazard by adapting and recovering

41
Q

What are factors affecting the ability to cope?

A
  • location
  • resilience
  • preparedness
  • tech
  • knowledge of threat
  • community adaption/ability to react
  • governance
42
Q

What is the hazard risk equation?

A

Risk = hazard x vulnerability / capacity

43
Q

What is the volcanic explosivity index?

A

measure explosiveness (1= small and gentles -> 8 = colossal

44
Q

What are factors that affect resilience/vulnerability?

A
  • education
  • housing
  • healthcare
  • income
  • food
  • utilities/governance
  • age
  • disability
45
Q

What is a tectonic mega-disaster?

A
  • large scale by area or socio-economic impact
  • serious problems for management
46
Q

What is a high impact low probability event?

A

impossible to predict but very likely to occur over long time scales - require rapid global response and less resilience from globalisation

47
Q

What is an example of a multiple hazard zone?

A

Philippines

48
Q

What is a tiltmeter?

A

react to change in ground levels

49
Q

What is a gas measure?

A

radon gas can be released before an earthquake

50
Q

What a mitigation strategies for volcanoes?

A
  • land use zoning
  • volcanic use zoning
  • lava walls/channels
51
Q

What is recovery?

A

restoration of services, rebuilding infrastructure and socio-economic recovery after an event

52
Q

What is a micro management strategy?

A

Strengthen individual buildings

53
Q

What is a macro management strategy?

A

Large scale protective measures

54
Q

What is hazard resistant engineering?

A

Reinforced concrete and steel cross-bracing
Internal Pendulum to decrease displacement
Base isolation, shock absorbers
Retrofitting old buildings

55
Q

What are cheap engineering techniques?

A
  • lighter material and single story
  • sloped roofs to prevent ash build-up
  • elevated buildings