Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Geography > Tectonics > Flashcards

Tectonics Flashcards

You may prefer our related Brainscape-certified flashcards:
U.S. Geography flashcards World Geography flashcards
1
Q

Where do the majority of tectonic hazards occur and what % of earthquakes are found in the Ring of Fire in the Pacific Ocean?

A

At plate boundaries, 70%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why do most tectonic hazards take place at plate boundaries?

A

Plate boundaries can slide past or crash into each other so tectonic strain builds up between plates and when pressure exceeds friction, the rock fractures and huge amounts of energy released in form of seismic waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is ground-shaking in an earthquake?

A

Brittle crust either side of the fracture rebounding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the order of explosivity of different boundary types?

A

O-O –> O-C –> C-C
least explosive –> most explosive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What makes volcanoes more explosive at certain plate boundaries?

A

High silica content so high viscosity so high gas content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the case studies for an effusive, explosive, and very explosive volcano and what type of magma did each have?

A

Effusive: Iceland 2010 - basaltic
Explosive: Mt. St. Helen’s 2010 - andesitic
Very explosive: Mt. Pinatubo 1991 - rhyoltic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What was the VEI of the Icelandic eruption in 2010?

A

VEI 4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What was the VEI of the Mt. Pinatubo eruption in 1991?

A

VEI 6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which type of plate movement has a shallow focal depth and why is this dangerous?

A

Conservative - seismic energy has less distance over which it can dissipate so higher magnitude earthquake due to tectonic strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the case study for conservative plate movement, what was its focal depth, and what was its magnitude?

A

Haiti 2010, 13km, 7.0 magnitude

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which plates were involved in the 2010 Chile earthquake?

A

Nazca and South American plates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What was the magnitude of the 2010 Chile earthquake and how many people were killed?

A

8.8 magnitude, 525 people killed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What type of plate movement was involved during the 2010 Chile earthquake and why did this make it so dangerous?

A

Convergent, shallow focal depth so greater intensity ground-shaking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where and how do intra-plate earthquakes occur?

A

Occur along ancient faults, slip easily to accommodate regional strain so forces exerted at all sides and strain on ancient fault produced which releases energy in form of seismic waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why are intra-plate earthquakes sometimes more dangerous than ones at plate boundaries?

A

Usually low level of preparedness as they are considered as low risk due to not being located at a plate boundary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the case study for an intra-plate earthquake?

A

Gujarat, India 2001

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What was the magnitude and how many people were killed as a result of the 2001 Gujarat, India earthquake?

A

7.7 magnitude, 20,000 people killed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a volcanic hotspot?

A

Area of mantle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How can a volcanic hotspot create a volcanic island chain?

A

Heat rises as stationary thermal plume, high heat and low pressure at base of lithosphere melts rock so molten rock rises through cracks and erupts on Earth’s surface, tectonic plates move over stationary hotspot and oceanic volcanoes can cool, forming volcanic island chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is an example of a volcanic island chain?

A

Hawaii

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How hot is the inner core and what is this caused by (convection currents)?

A

6000°C, caused by radioactive decay

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What causes the mantle to become less dense and rise into the lithosphere (convection currents)?

A

Heat from the inner core radiates into the outer core and then the mantle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which direction is the mantle forced in when it becomes less dense and rises into the lithosphere (convection currents)?

A

Sideways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What happens to the mantle after it is forced sideways in the lithosphere (convection currents)?

A

Cools down and becomes more dense so sinks back down to the core to form a convection current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What causes plate movement, what is this process known as, and what is the application for this (convection currents)?

A

Friction between slow-moving mantle and crust, convection traction, Nazca plate moves at 8cm/year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What drags the rest of the plate into the subduction zone (slab pull)?

A

Enormous weight of tectonic plates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What happens after the rest of the plate is dragged down into the subduction zone (slab pull)?

A

Plate is cooler as it is dragged down towards mantle so more dense than surrounding mantle which further facilitates plate movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

At which boundaries does slab pull take place and what is an example?

A

Oceanic-continental boundaries, Ring of Fire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Wadatti-Benioff Zone definition

A

Area of seismicity that corresponds with a slab being thrust downwards in the subduction zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is an example of a Wadatti-Benioff Zone?

A

Nazca plate subducting beneath South American plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What generates varying focal depths in the Wadatti-Benioff Zone?

A

Different rates of movement of crustal rock at various points

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the focal depth of a fracture also known as and what is it important in determining?

A

Focal point = hypocentre, important in determining surface magnitude

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Which are the most dangerous seismic waves?

A

L waves - high amplitude

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are the 3 secondary hazards of earthquakes?

A

Landslides, liquefaction, tsunamis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Which communities are at risk to landslides?

A

Communities located at bottom of a steep slope comprised of unconsolidated sediment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How does a landslide occur?

A

Ground-shaking and gravity cause loosely-packed sediment to fall down slope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is the case study for landslides and how many people were killed?

A

El Salvador 2001, killed 585 people

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Which communities are at risk of liquefaction?

A

Communities located over loosely-packed, saturated ground

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

How does liquefaction occur?

A

Shaking causes ground to lose strength as friction between particles has been reduced so ground behaves like a liquid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is the case study for liquefaction and how many houses were destroyed?

A

Niigata, Japan 1964, 3,500 houses destroyed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Which communities are at risk of tsunamis?

A

Communities located at O-C convergent coastlines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

How does a tsunami occur?

A

Upward movement of ocean floor along boundary displaces low-lying column of water which creates ripple with long wavelength and small amplitude, amplitude increases as reaches land

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is the case study for tsunamis and how many people were killed?

A

Boxing Day Tsunami 2004, 225,000 died over 12 countries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What are the 4 primary hazards of a volcano?

A

Pyroclastic flows, tephra, lava flows, gas eruptions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are pyroclastic flows?

A

Large, dense clouds of hot ash and gas that erupt out of side vents

46
Q

How can pyroclastic flows destroy property?

A

Force of explosion causes material to travel downhill at high speeds and at temperatures of 1000°C

47
Q

What is the case study for pyroclastic flows and how many people were killed?

A

Montserrat 1997, killed 19 people

48
Q

What is tephra?

A

Rock fragments that can vary in size from ash particles to lava bombs and are ejected into atmosphere

49
Q

Why is tephra dangerous?

A

Causes large areas to be blanketed in ash which kills vegetation, poisons water, and causes buildings to collapse

50
Q

What is the case study for tephra, how big was the tephra cloud, and what did it cause?

A

Iceland eruption 2010, 10km tephra cloud, caused global flights to be cancelled

51
Q

What are the 2 secondary hazards of a volcano?

A

Lahar, jokulhlaup

52
Q

How is a lahar formed?

A

Particles of ash trigger heavy rain which remobilises fallen ash and causes volcanic mudflow

53
Q

What is the case study for lahars and how much sediment destroyed farmland?

A

Mt. Pinatubo 1991, 3km³ of sediment

54
Q

What does the Deggs Model show?

A

Shows interaction between geophysical hazard and vulnerable pop. - disaster occurs when vulnerable pop. exposed to hazard

55
Q

What is the case study used for the Deggs Model?

A

Mt. Pinatubo 1991

56
Q

How large was Pinatubo’s tephra cloud and why did this lead to disaster (Deggs Model)?

A

24km tephra cloud, vulnerable pop. didn’t have slanted roofs so ash accumulated and roofs collapsed

57
Q

What is the Hazard-Risk Formula and what does it do?

A

Risk = hazard x exposure x vulnerability - breaks down the components of risk

58
Q

What is the case study used for the Hazard-Risk Formula and what is the application for each component of risk?

A

Haiti 2010, hazard: 7.0 magnitude and 13km focal depth, exposure: 25% of pop. 20km from epicentre, vulnerability: brittle housing

59
Q

What does the Disaster-Age Index show and what is the case study used for it?

A

Children and elderly more likely to suffer from hazards (weaker immune systems, less mobile), Tohoku 2011

60
Q

How many people died as a result of the Tohoku 2011 earthquake and what % were aged 65+ (Disaster-Age Index)?

A

15,000 died, 55% aged 65+

61
Q

What does the PAR model show and what is the case study for it?

A

Shows progression of vulnerability as a form of pressure, Haiti 2010

62
Q

What was the root cause of vulnerability in Haiti (PAR model)?

A

Low levels of economic development

63
Q

What % of Haiti’s population are living on less than $2/day (PAR model)?

A

72%

64
Q

What was the dynamic pressure of vulnerability in Haiti (PAR model)?

A

Poverty - majority of residents couldn’t afford to build aseismic houses

65
Q

What were the unsafe conditions in Haiti and what % of buildings were made of weak concrete (PAR model)?

A

Brittle housing, 90% made of weak concrete

66
Q

What was the magnitude of the Haiti earthquake and how many people died as a result?

A

7.0 magnitude, 230,000 died

67
Q

What is VEI a measure of, how is it calculated, what is the scale, and what kind of scale is it?

A

Explosivity, calculated by volume of ejected tephra and height of eruption cloud, 0-7, logarithmic (increase of 1 = explosion is 10x more powerful)

68
Q

What is MMS a measure of, what is it based on, and what is the scale?

A

Seismic energy released, based on seismic movement of earthquake, 0-9

69
Q

What are the 6 factors of a hazard that influence the scale of a disaster?

A
  1. Magnitude (LE: preparedness)
  2. Speed of onset (LE: magnitude)
  3. Duration (LE: mag.)
  4. Areal extent (LE: which hazard)
  5. Spatial predictability (LE: mag.)
  6. Frequency (LE: mag.)
70
Q

What were the speeds of onset for the Haiti 2010 and Tohoku 2011 earthquakes?

A

Haiti: 0s
Tohoku: 60s

71
Q

What were the durations of the Haiti 2010 and Tohoku 2011 earthquakes?

A

Haiti: 30s
Tohoku: 6 mins

72
Q

Which human factors can increase vulnerability?

A

Education, income, housing, healthcare, nutrition

73
Q

How many people died of cholera after the Haiti earthquake and how did this occur (poor healthcare increasing vulnerability)?

A

10,000 killed, contamination of water sources by UN peacekeepers so water-borne diseases arose and poor healthcare so less likely to recover

74
Q

What % of school-aged children attend school in Haiti and why is this an issue (poor education increasing vulnerability?

A

50%, less qualified so less earning potential so decreased ability to afford aseismic housing OR less knowledge of what to do in event of an earthquake so less likely to evacuate

75
Q

What % of Haiti’s population face food insecurity and why is this an issue (poor nutrition increasing vulnerability)?

A

42%, weaker immune systems due to malnutrition so less likely to survive spread of disease in aftermath of a hazard

76
Q

What are mega-events?

A

High impact, low probability events

77
Q

Why was the Boxing Day 2004 tsunami classed as a mega-disaster?

A

Many countries affected and long-term economic impacts - 90% drop in hotel bookings

78
Q

Why was the Iceland 2010 earthquake classed as a mega-disaster?

A

Had impacts on global economy and supply chain - 100,000 air journeys were cancelled which cost airlines £130m/day

79
Q

What are multiple hazard zones?

A

Areas where a number of physical hazards combine to create an increased level of risk

80
Q

Which areas are generally classed as disaster hotspots?

A

Located at a plate boundary, high density of people (urban), developing countries

81
Q

What are the 4 stages of the hazard management cycle?

A
  1. Response
  2. Recovery
  3. Mitigation
  4. Preparation
82
Q

How much did the EU pledge to help Haiti in providing food and shelter after the 2010 earthquake (response)?

A

£122 million

83
Q

Who aided reconstruction of key infrastructure in Haiti after the 2010 earthquake (recovery)?

A

World Bank

84
Q

What are carried out and built in the mitigation stage of the hazard management cycle?

A

Risk assessments carried out, hazard-proof buildings built

85
Q

What national day does Japan hold on 1st September every year (preparation)?

A

National Disaster Prevention Day

86
Q

What is an evaluation of the hazard management model?

A

Researchers argue that cycle is too generic and unquantifiable

87
Q

What does the Parks model help us to understand and what is it useful for?

A

The time dimension of resilience, useful to compare events

88
Q

What are the 4 stages of the Parks model?

A
  1. Hazard
  2. Deterioration from normality
  3. Response and hazard management (length depends on governance)
  4. Recovery - normality and improving infrastructure
89
Q

What is an evaluation of the Parks model?

A

Researchers argue that it doesn’t account for different models of economic, social, or political development

90
Q

Forecasting definition

A

Providing % chance of a hazard occurring based on past events

91
Q

Prediction definition

A

Knowing when and where a hazard will occur on a spatial and temporal scale

92
Q

Which natural hazards can be predicted and which can’t?

A

Can be: Volcanoes (but not magnitude), tsunamis (partially)
Can’t be: Earthquakes (but can forecast risk)

93
Q

Which 2 pieces of equipment can be used to predict a volcano and what do they do?

A
  1. Tilt meters - record volcano “bulging” as magma rises
  2. Gas spectrometer - analyses gas emissions
94
Q

What formed before the Mt. Pinatubo 1991 eruption occurred and how many were evacuated?

A

Bulge and lava dome, 25,000 evacuated

95
Q

How can an earthquake event be managed?

A

Base isolation

96
Q

How does base isolation manage an earthquake event?

A

Building is built away from ground on flexible pads known as base isolators so building shaking is reduced or doesn’t happen

97
Q

What % does base isolation reduce damage to key structures by and how many buildings in Japan use base isolation?

A

80%, 9,000 buildings

98
Q

What is an evaluation for base isolation in managing an earthquake event?

A

Expensive so unlikely to be an option for a developing country

99
Q

How are tsunami events managed?

A

Sea walls prevent tsunami from travelling inland by slowing the flow

100
Q

How many km of sea walls have been built in Japan since 2011 and how much did this cost?

A

395km, cost £9.1 billion

101
Q

What is an evaluation for sea walls managing tsunami events?

A

Provides a false sense of security as magnitude of tsunami may overcome sea wall and prevents residents from being able to see ‘natural’ warning sign of water retreating

102
Q

How are volcanic eruption events managed?

A

Diverting lava flow

103
Q

How does diverting lava flow manage a volcanic eruption event?

A

Lava sprayed with sea water which solidifies and creates a wall which leads to a diversion

104
Q

What is an evaluation for diverting lava flows managing a volcanic eruption event?

A

Dependant on location (can only be used at coastal regions)

105
Q

How can vulnerability in an earthquake event be managed?

A

Preparedness and education

106
Q

How does preparedness and education manage vulnerability in an earthquake event (Japan application)?

A

Preparedness - 5pm every day Tokyo plays song on loudspeakers to test earthquake warning systems

Education - National Disaster Prevention Day

107
Q

What is an evaluation for preparedness and education managing vulnerability in an earthquake event?

A

Warning systems need to be inclusive for old/young/disabled people

108
Q

How can vulnerability in a tsunami event be managed?

A

Networks of sensors can be used to detect a tsunami and communications infrastructure can be used to alert coastal areas

109
Q

What is an evaluation for managing vulnerability in a tsunami event?

A

Elderly may not have access to phones or internet data so don’t receive tsunami alerts

110
Q

How can loss from a natural hazard event be managed?

A

International aid e.g. UN peacekeepers in Haiti

111
Q

What is an evaluation for international aid managing loss from a natural hazard event?

A

UN peacekeepers caused the spread of cholera in Haiti by contaminating water sources so a further 10,000 people were killed

Geography (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions