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Geography > Tectonic Processes & Hazards > Flashcards

Tectonic Processes & Hazards Flashcards

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1
Q

What is the word for splitting up land-use between different areas of a city to make sure there are no houses on unstable land?

A

Zoning

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2
Q

Examples of good government preparation for natural disasters?

A

Meeting basic needs
Tackling corruption
Land-use planning
Community awareness programmes

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3
Q

What are the 3 types of boundaries?

A

Divergent
Convergent
Conservative

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4
Q

Tsunamis

A

Caused by submarine shock waves generated by earthquake or volcanic eruptions. Displacement of the water column.

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5
Q

What is a risk?

A

The likelihood of humans being affected by a hazard.

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6
Q

What is the hazard risk equation?

A

Risk = (hazard x vulnerability) / capacity to cope

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7
Q

Vulnerability

A

How susceptible a population is to damage caused by a hazard

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8
Q

Capacity to cope/resilience

A

How well a population can recover from a disaster

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9
Q

What is a disaster?

A

When a hazard affects a humans wellbeing.

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10
Q

What does Dreggs disaster model suggest?

A

A disaster only happens when a hazardous even meets a vulnerable population

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11
Q

Conservative PB

A

Plates move past each other but at different speeds, causing friction and collisions

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12
Q

Constructive PB

A

Plates moving apart from one another

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13
Q

Primary hazards of a volcano are…

A

Pyroclastic flow
Tephra (ash falls)
Lava flows
Volcanic gas

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14
Q

Secondary hazards of volcanoes are…

A

Lahars

Jokulhaups

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15
Q

Destructive

A

Plates move towards each other, colliding head-on if both continental. If one is continental and the other is oceanic, subduction will occur where the oceanic plate is thrust under the continental. If its two oceanic plates, the heavier plate will be forced under the other.

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16
Q

Earthquakes at constructive boundaries

A

Plates move at different speeds which builds pressure until plates crack, causing fault lines. This results in the release of seismic waves, producing earthquakes.

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17
Q

Earthquakes at destructive boundaries

A

One plated forced under, getting stuck due to friction which produces energy. As plates suddenly jerk past each other this energy is quickly released forming a powerful earthquake.

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18
Q

Earthquakes at conservative boundaries

A

Plates lock with one another which, when pressure is build produces sudden seismic waves.

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19
Q

P Waves

A

Immediate shock - fastest traveller

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20
Q

S Waves

A

Longer wavelength, arrives seconds later

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21
Q

L Waves

A

Only travel through the crust, causes horrizontal movement

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22
Q

Volcanoes at constructive boundaries

A

Magma is less dense than the plate so rises above it, forming a volcano, such as those within the Rift Valleys

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23
Q

Volcanoes at destructive boundaries

A

Subduction causes the melting of the oceanic plate, allowing for magma to rise on the crust to form a volcano. Usually more explosive. E.g Mt. St. Helens

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24
Q

Volcanoes at conservative boundaries

A

Volcanoes do not form at conservative boundaries

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25
Q

Parks Model:

A

Takes into account that different hazard events have diferent impacts so vary in their duration, speed and destruction of quality of life. The 3 lines are representative of a countrys response and ability to manage the disaster

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26
Q

Strategies to modify the event :

A
  • Land-use Zoning: Where it is the safest to build infrastructure
  • Hazard-Resistant Design: Invest and produce in long-term construction projects
  • Engineering Defences: Stronger sea walls or mangrove forests
  • Diversion of Lava Flows: Spraying seawater to cool and solidify lava flow
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27
Q

Strategies to modify the vulnerability and resilience:

A
  • Hi-tech Monitoring: International satellites and aircraft monitor changes in the earth
  • Prediction: Observing changes in volcanic shapes or earthquakes
  • Education: Teaching communities about hazards
  • Community Preparedness: Earthquake drills and alarms prepare communities
28
Q

Strategies to modify loss:

A
  • Emergency Aid: This can can be long term or short term but can make a country dependent
  • Insurance: Some may rely on insurance to recover losses
29
Q

The economic impacts of a tectonic hazard are influenced by:

A
  • Level of economic development (GDP per capita)
  • Population
  • Resilience
  • Urbanisation
  • Insurance
30
Q

what makes Haiti vulnerable?

A
  • one of the poorest countries in the world with a HDI of 0.493
  • corruption within government
  • weak infrastructure
  • informal, unsafe living conditions
  • lacking of planning and prep
  • poverty (slums)
31
Q

how has Japan reduced its vulnerability?

A

-developed so have financial resources
-adequate buildings due to enforced regulations
-some tsunami defences
-disaster plans: education and evacuation
however
-assets vulnerable (Fukushima)
-economically vulnerable due to wealth and trade links

32
Q

what is the governance like in Haiti?

A

decades of corrupt, ineffective and brutal government left Haitian people vulnerable due to slum housing, ineffectual water supply and endemic poverty.

33
Q

what is the governance like in Japan?

A

developed so have:

  • widespread insurance schemes
  • government run preparation programmes (e.g Japans disaster prevention day each year)
  • monitoring systems and defences
  • regulated local planning systems
34
Q

other than tectonic hazards, what is the other hazard called and why have they become more common in recent years?

A

Hydro-met hazards (hydro-meteorological hazards)
hazards such as floods, storms, cyclones and drought. increasing possibly due to global warming and human environmental management issues such as. deforestation.

35
Q

what are some trends of tectonic hazards?

A
  • hasn’t been a change in the number of tectonic hazards since 1980; 15-40 each year
  • the trend for earthquake economic losses is upwards, averaging about $20-40 billion per year.
36
Q

what is a mega-disaster?

A

a high magnitude, high impact, infrequent disaster that affect multiple countries directly or indirectly meaning their impacts are regional or global.

37
Q

what are two examples of mega-disasters and what were their main impacts?

A

2011 Japan tsunami- only effected Japan directly but the economic impacts had global consequences as Japan faced disruptions to ports, factories and power supplies which effected supply chains and global business transactions
2010 Eyafjallajokul eruption- over 20 European countries were affected by total or partial closure of airspace as the Asch cloud disrupted air travel leading to 100,000 cancelled flights costing over £1 billion in losses.

38
Q

what is a multiple hazard zone?

A

regions prone to two or more hazards, and in some cases can interact to produce complex disasters.

39
Q

what is meant by a prediction?

A

knowing when or where a natural hazards will strike on a spatial and temporal scale that can be acted on meaningfully in terms of evacuation

40
Q

what is meant by forecasting?

A

much less precise than predicting, it provides a percentage chance of a hazard occurring
e.g 25% chance of a magnitude 7 earthquake in the next 20 years

41
Q

can you predict earthquakes? give further information

A

NO

  • only areas at high risk and areas likely to suffer from severe ground shaking and liquefaction can be identified (risk forecasting) and used for land use zoning
  • ‘seismic gaps’ ; areas that haven’t experienced an earthquake for some time or are ‘overdue’, can signify high risk.
42
Q

can you predict volcanic eruptions? give further info

A

YES

  • monitoring equipment on volcanoes can measure changes as magma chambers fill when an eruption is nearing
  • Tiltmeters and strain meters record volcanos magma movement when it rises
  • gas spectrometers analyse gas emissions which can signal an increased likelihood of an eruption
43
Q

can you predict a tsunami? give further info

A

PARTLY

  • an earthquake induced tsunami cannot be predicted
  • however seismometers can detect and locate an earthquakes occurrence, then the ocean monitoring equipment can detect a tsunami
  • this info can be relayed to coastal areas to start preparations for evacuated.
44
Q

what do perditions of events rely on? and why isn’t it accessible to all?

A

technology
developing countries like India in 2004 don’t have the motoring equipment meaning warning systems are as accurate and quick enough to be effective

45
Q

what does the hazard/disaster management cycle show?

A

the different stages of managing a hazard in an attempt to reduce the scale of the disaster.
shows:
preparedness-community education, predictions, warning and evacuation systems
mitigation-acting to reduce the scale of the next disaster; land use zoning, hazard-resistant buildings and infrastructure
response-immediate help in the form of rescue to save lives and aid to keep people alive
recovery-rebuilding infrastructure, and services, rehabilitating the injured.

46
Q

what do the recovery stages depend on?

A
  • the magnitude of the disaster
  • development level (the lower, the more severely affected)
  • governance (better= well diverted resources
  • external help
47
Q

what is meant by a hazard resistant design?

A

invoices constructing buildings and infrastructure that are strong enough to resist tectonic hazards. in the case of an earthquake, they are called aseismic buildings.

48
Q

what is cry wolf syndrome?

A

something that occurs when predictions and evacuations prove to be wrong, so people are less likely to believe the next prediction and warnings and therefor fail to evacuate

49
Q

what is a threshold?

A

a magnitude above which a disaster occurs. this threshold level could be difference in a developed vs developing country because of the different levels of resilience.

50
Q

when is the impact of an event considered to be a disaster?

A
  • 10 or more deaths
  • 100 or more people affected
  • US$1 million in economic losses
51
Q

why is the relationship between magnitude and death toll a weak one?

A
  • some earthquakes cause serious secondary impacts, such as landslides and tsunamis
  • earthquakes hitting urban areas have a greater impact than those in rural areas.
  • level of development and level of preparedness affect death toll
  • isolated, hard to reach places could have a higher death toll because rescue and relief take longer.
52
Q

what is an earthquakes intensity measured using?

A

the Mercalli scale

53
Q

what is an earthquakes magnitude measured using?

A

the moment magnitude scale (MMS)

updated version of the Richter scale

54
Q

what is the magnitude of an eruption measured using?

A

volcanic explosive index (VEI). ranges from 0 to 8 and is a composite index combining eruption height, volume of material erupted and duration of eruption.

55
Q

what is a super volcano?

A

one whose impacts would be felt globally because of a worldwide cooling of the earth’s climate perhaps up to 5 years.

56
Q

what can tectonic events be compared using?

A

Hazard profiles.

57
Q

what is liquefaction?

A

a process that occurs in waterlogged, loose sediments; earthquakes shaking ‘liquefies’ the ground, causing buildings to tilt, sink and collapse.

58
Q

what are some factors that help explain the impacts of a hazard?

A

social: poverty, population density
economic: poor building construction, governance
environmental: time of day, geology, terrain, isolation, duration, secondary hazards

59
Q

what does a lower HDI suggest in terms of tectonic impacts?

A

a higher death toll.
chile (2007)- HDI of 0.83, death toll of 2
Pakistan (2013)- HDI of 0.54, death toll of 825

60
Q

what are some factors increasing risk of tectonic hazard and mitigating (reducing) risks of a tectonic hazard?

A

increased risk:

  • population growth
  • urbanisation and urban sprawl
  • environmental degradation
  • loss of community memory about hazards
  • very young or old population
  • ageing, inadequate infrastructure
  • greater reliance on power, water and communication systems.

mitigating risk:

  • warning and emergency-response systems
  • economic wealth
  • government disaster-assistance programmes
  • insurance
  • community initiatives
  • scientific understanding
  • hazard engineering
61
Q

in areas of low HDI (bellow 0.55), vulnerability is usually high because of what reasons?

A
  • many people lack basic needs of sufficient water and food even during ‘normal’ times.
  • much housing is informally constructed with no regards for hazard resilience
  • access to healthcare is poor, and diseases and illnesses are common
  • education levels are lower, so hazard perception and risk awareness are low.
62
Q

what is meant by an aftershock?

A

events that occur in the hours, days and months after the primary earthquake and can be of high magnitude.

63
Q

what does governance refer to?

A

the process by which a country or region is run.

64
Q

what are three key geographical factors that influence the impact of a hazard?

A

POPULATION DENSITY- highly populated areas are harder to evacuate such as Mt Vesuvius, Italy, and are likely to be hit harder by earthquakes
DEGREE OF URBANISATION- when cities are struck by major earthquakes, such as Japan or Haiti, death toll can be high because of the concentration of at-risk people
ISOLATION AND ACCESSIBILITY- often rural areas are hit less hard that urban areas by the initial impacts of a tectonic disaster, but isolation and limited access can slow relief effort. e.g the 2005 Kashmir earthquake.

65
Q

what assets to urban areas have that rural areas don’t which increase resilience?

A

hospitals, emergency services, food stores and transport connections.

66
Q

what do countries like Japan, the USA and Chile have that ensure social impacts are reduced?

A
  • advanced and widespread INSURANCE, allowing people to recover from disasters- at least in the long-term
  • government run PREPARATIONS such as Japan’s disaster prevention day on 1 September each year, as well as public education about risk, coping, responding and evacuating
  • sophisticated MONITORING of volcanoes and, where possible, defences such as tsunami walls
  • regulated local PLANNING SYSTEMS, which use land-use zoning and building codes to ensure buildings can withstand hazards and are not located in areas of unacceptable risks.

Geography (3 decks)

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