Tectonic processes Flashcards
(187 cards)
1
Q
What is subduction?
A
- An oceanic plate gets pushed under a continental plate because it is more dense
2
Q
What is slab pull?
A
- As rock descends and subducts, it pulls the rest of the plate down
3
Q
What is ridge push?
A
- At sites where oceanic curst is created, the new crust formed pushes the existing crust away from the ridges.
- This has a smaller force than slab pull
4
Q
What is the lithosphere?
A
- The rock layer (cool, rigid and brittle)
- The curst and upper mantle
- The base is 1300C
5
Q
What is the asthenosphere?
A
- Below the lithosphere
- Hotter and weaker than the lithosphere
- Capable of plastic flow when stress is applied
6
Q
What happens at a destructive plate boundary?
A
- An oceanic and continental plate are moving towards each other
- The oceanic plate subducts under the continental plate because it is less dense (slab pull)
- The oceanic plate starts to melt (due to friction and heat), and rise which causes magma to burst through the crust
-Gives explosive volcanoes and massive earthquakes
7
Q
Examples of destructive plate boundaries.
A
- The Andes mountains in South America - The oceanic Nazca plate subducts under the continental South American plate
8
Q
What happens at a collision plate boundary?
A
- Two continental plates meet, and fold upwards (because they are both the same density, so no subduction occurs)
-Only earthquakes occur here
9
Q
Examples of collision plate boundaries.
A
- Mount Everest in the Himalayas - the Indian and Eurasian plates meet
10
Q
What happens at a constructive plate boundary?
A
- Two plates move away from each other, leaving a space for magma to rise through
-Minor earthquakes and volcanoes can occur here
11
Q
Examples of a constructive plate boundary.
A
- The mid Atlantic ridge - the North American and Eurasion plate are moving away from eachother
12
Q
What happens at a conservative plate boundary?
A
- Two continental plates move past eachother in opposite directions, or in the same direction but at different speeds
-Only earthquakes happen here
13
Q
Examples of conservative plate boundaries.
A
- San andreas fault in the US - Pacific and North American plates
14
Q
What heats the magma to create convection currents?
A
- Heat is radiated outward from the inner core, due to radioactive decay that is happening here
15
Q
What is a mantle plume?
A
- A column of magma
- High heat and low pressure causes the lithosphere to melt - magma rises through the cracks to the surface and erupts, forming a volcano
16
Q
How do tectonic plates move?
A
- Mantle convection cells make contact with the base of the crust, and move the plates by frictional drag.
- Slab pull causes plates to move at subduction zones
- Mantle plumes push the crust upwards on a large scale
17
Q
Where do most earthquakes happen?
A
- About 70% are found in the Pacific ring of fire
- Oceanic/continental fracture zones
- Intra plate earthqaukes
18
Q
Where do intra plate earthquakes occur?
A
- They may happen along old fault lines in the middle of plates
19
Q
Who came up with the theory of continental drift?
A
- Alfred Wegner
20
Q
What was the fossil evidence for the theory of continental drift?
A
- Fossils of the same green plants have been found on almost all continents, suggesting that they all once had similar climates
-Glossopteris (plant)–> South America, Africa, India, Antarctica, Australia
20
Q
What state is the mantle in?
A
- The mantle is semi plastic (plastic flow), so the material is solid, but it can flow like a liquid - this is what makes up convection currents
21
Q
What was the glacial evidence for the theory of continental drift?
A
- The pattern glaciers made as they moved across the Earth’s surface doesn’t make sense, unless aranged how Wegner proposed
-Patterns show that glaciers formed in the oceans and moved onto the land, however we know this cannot be true
22
Q
What was the rock evidence for the theory of continental drift?
A
- Mountain ranges in countries across different continents contain similar rock, and formed around the same time
-When using Wegner’s map, these ranges match up
23
Q
What was the problem with Alfred Wegners thoery of continental drift?
A
- He could not explain what caused the continents to move
24
What are convection currents?
* Magma is heated, so rises -it then cools and sinks again
-This causes a circulating convection cell
25
What is sea floor spreading, and who came up with this idea?
* Harry Hess in 1962
* The sea floor itself moves and carries continents with it, as it expands from a central point
26
How does sea floor spreding work?
* Molten magma comes up between the plates in a rift in the sea floor
* As the hot magma cools, it expands and pushes on the plates beside it
27
What evidence supported the thoery of sea floor spreading?
* The age of the rock on the ocean floor - the newest rock is found along the ridges in the ocean
* Paleomagnetism - evidence of pole reversals in the rock shows that new rock is continuosly forming
28
What is paleomagnetism?
* New magma that is erupted 'locks in' the Earth's magnetic polarity when it cools
* Scientists use this to determine historic periods of large scale volcanic activity by creating a geo-timeline
* This is because the Earth's magnetic field reverses about once every 200,000 years (this varies) - rocks that contain magnetic material record those pole reversals
29
How does the use of GPS support the theory of continental drift?
* Measurments of the land can be made, giving precise information about the changes to the Earth's surface
30
Define the theory of plate tectonics.
* All of the Earth's surface is made of tectonic plates that move, causing major geological events along the boundaries between them
-Similar to the theory of continental drift, but uses information collected since Alfred Wegner
31
Why is the theory of plate tectonics significant?
* It ties together continental drift, sea floor spreading, magnetic field reversals, and convection in the mantle
32
Describe the stick and release model for earthquakes.
* Plates move ad get stuck because of friction
* Pressure/strain builds in the plates
* When the elastic strain energy exceeds friction and the strength of the fault, the rock fractures
* There is a sudden release of energy in the form of seismic waves (an earthquake)
| Elastic strain energy = force pushing plate
32
What is the Benioff zone?
* Where rock is subducted in the subduction zone
33
What is the hypocentre/focus?
* Where energy is first released
-This can happen anywhere in the benioff zone
* Different speeds and movements of rock produce differently focused earthquakes
-Shallow focus earthquakes are the most damaging
-Deep focuses can be up to 700km
34
What are the features of secondary waves?
* Half the speed of P-waves (4km/second)
* Vibrate perpendicular to the direction of travel (transverse)
* Cannot travel through liquids
* Cause the most destruction
34
What are the features of primary waves?
* Fastest travelling (8km/second)
* Compressional (longitudinal) - vibrate in the direction in which they are travelling
* Have a short wavelength
* Able to travel through water/liquid
* Cause liquefaction
35
What are the features of surface (L) waves?
* Travel the slowest
* Near to the ground surface
* Some shake the ground perpendicular to the direction of wave movement (transverse)
* Some have a rolling motion that produces vertical ground movement (horizontally)
* Do not travel through liquids
36
What is liquefaction?
* It is the process by which water - saturated material can temporarily lose normal strength and behave like a liquid under the pressure of strong shaking
-Only occurs with unconsolidated material
| Sediments that haven't been lithified -turned into rock
36
How does liquefaction work?
* There are pore spaces between particles of sediment
* When the ground shakes, these particles vibrate and move apart
* The pore spaces increase in size, so can fill with water
37
Why is liquefaction a hazard?
* When pressure is applied to the liquefied material, it can sink
* Buildings can sink and get stuck in the ground, when it regains its normal strength
* Can cause infrastructure to sink/become unusabl/be destroyed
* Can lead to planning zones for new buildings
38
What are landslides?
* The mass movement of loose material or debris down a slope
38
What can increase the chances of a landslide occurring/make a landslide worse?
* Heavy rainfall - saturates the material
* A very high magnitude
* A very steep relief
* Very fine sediment
39
How does geology affect secondary hazards that occur?
| Christchurch earthquake
* The port hills had fine grained, dense black basalt
* Around christchurch, there is lots of fine grained sediment
40
What causes a tsunami?
* High levels of water displacement
-Earthquakes (plates upthrust underwater)
-Subsea volcanoes/volcanoes with enough materials fallen into the water
-Landslides
-Meteors/asteroids
41
How does a tsunami work?
* Water is displaced - this than moves outwards/across to the lower areas because of gravity
* Waves are generated and move out in all directions across the ocean
* As waves enter shallower water, they compress, their speed slows, and they build in height
41
What does the impact of a tsunami depend on?
* Duration of the event
* Wave amplitude, water column displacement, and distance travelled
* Depth and gradient of the coastline
* Degree of coastal ecosystem buffer to dissipate energy - e.g. mangroves, coral reefs
* Timing of the event and quality of the warning systems
* Level of coastal development and proximity to the coast
42
How are volcanoes formed at subduction zones?
* Movement from convection currents and slab pull, causes the oceanic plate to subduct
* The friction from this causes magma to heat and rise - becomes less dense
* The hot magma melts its way through the crust, and causes a volcano
42
How are volcanoes formed at divergent plate boundaries?
* Convection currents cause plates to move away from eachother
* This leaves a gap/weak area magma can break through
43
How are hotspot volcanoes formed?
* They are formed over mantle plumes - weaknesses in the crust
43
What are primary and secondary hazards from volcanoes?
* Primary
-Lava flows
-Pyroclastic flows
-Ash falls
-Gases
* Secondary
-Landslides
-Flooding
-Tsunamis
43
What are the causes, characteristics and effects of Pyroclastic flow?
| Plus an example - any composite volcano
* All explosive eruptions, or the collapse of an eruption column
* Hot gases, and broken fragments of rock ejected with a great velocity
* Rocks may be very large, and cause damage on impact
* Can travel a very long distance
| Mount Pinatubo, Phillipines - Mount Vesuvius, Italy
44
What are the causes, characteristics and effects of volcanic gases?
| Plus an example
* Any eruption
* Ash laden gases, including; CO, CO2, HCl, SO2
* Many are directly toxic
* Can contribute to acid rain
* CO2 can cause asphyxiation
* May cause long term starvation and disease
| 1700 asphyxiated by CO2 in the 1986 Lake Monoun eruption in Cameroon
44
What are the causes, characteristices and effects of Tephra?
| Plus an example
* All air bourne, or ground flowing pyroclasts
* Classified according to diameter size - Bombs (>64mm), Lapilli (2-64mm), Ash (<2mm)
* Ash means the sky can get dark, and global temperatures can reduce
* Can be spread over large distances
* Breathing it in can cause damage
* The weight of it on buildings can cause them to collapse
| Soufriere hills, Montserrat
45
What are the causes, characteristics, and effects fo lava flows?
## Footnote
Plus an example
* Any eruptions
* Flow rate is dependent on temperature (cooler lava increases viscosity and reduces speed)
* Can reach up to 100km away from the source
* Can cause fires
* Burial of land and objects
* Slow rate poses little risk to life
## Footnote
Mt. Nyiragongo DRC 2002. 3 rivers of lava poured down the Mt.'s sides towards town of Goma. 14 villages destroyed, 80% of Goma destroyed, 45 died and 100's injured
46
What are the causes, characteristics and effects of jokulhaulps?
| Plus an example
* Submarine eruptions displace large volumes of rock and water
* Blockage of rivers by lahars or lava flows
* Heat of eruption causes ice to melt
* Inundation fo fresh or salt water, may be gradual or rapid
* Dramatic changes in erosion and deposition patterns of rivers
* Destruction of property and agricultural land
| Mountains in Iceland (Ice melts from heat, causing flooding)
47
What are the causes, characteristics and effects of lahars?
| Plus an example
* Composite volcanoes - rain or meltwater can loosen tephra
* Volcanic mud-flows which may move downhill very rapidly (determined by topography)
* Extensive destruction to property
* Loss of life
| Nevado del Ruiz, Colombia 1985 - Mount Pinatubo, Phillipines 1991
48
What are the characteristics of basaltic lava?
* Most commonly at divergent/constructive plate boundaries
* Rich in iron and magnesium, low in potassium and sodium, lower in silica
* Low viscosity, usually hotter than other types, lowest gas content
* Dark in colour, fine grained mineral texture
* Creates shield volcanoes - layers of lava, and sometimes ash
| Temp around 1000-1200C
49
What are the characteristics of andesitic lava?
| Intermediate lava
* Usually found at convergent/destructive boundaries
* 'Middle' amount of metals, high percentage of silica, high in water and hydrochloric acid
* High viscosity lava, higher gas content, middle temp
* Light coloured
* Generates strong explosive eruptions and enormous eruption columns
* Forms composite volcanoes - layers of lava and ash
| Temp around 800-1000C
50
Why are volcanoes explosive?
| And what makes them more/less viscous?
* All magma contains gas dissolved in the liquid, and high pressure keeps this in the solution
-When the gas pressure is decreased, the volume of gas expands, and it bubbles
* The higher the gas content, the more explosive the volcano
-The amount of gas is related to its chemical composition
| Viscosity increases with increasing silica concentration in the magma
51
What are the characteristics of rhyolitic lava?
* Usually occurs at convergent boundaries
* Highest level of silica and sodium and potassium, and lowest level of heavy metals
* Highest viscosity, and lowest temperature
* Highest gas content and the most explosive
| Temp 650-800C
52
What makes a volcano hazardous?
* Type of lava (viscosity & gas content)
* The type of plate boundary
* The surrounding area and antecedent conditions - which can affect the amount of secondary hazards caused
* Population, and closeness to the volcano - surrounding infrastructure
* Magnitude of the earthquake
* Size of the volcano
* Type of volcano
* Level of development
53
What makes one place suffere more than another in a disaster?
* Relief
* Type of plate boundary
* Population density
* Level of development
* Antecedent conditions
* Type of hazard
* Time
* Geology
* Magnitude
54
What is a hazard?
* A percieved natural/geophysical event that has the potential to threaten both life and property
*
55
What is a disaster?
* The realisation of a hazard, when it causes a significant impact on a vulnerable population
* 10 or more people are killed, 100 or more people are affected
56
What can make a population vulnerable in terms of their physical and socioeconomic environment?
* Physical:
-Dangerous locations (geology, magnitude, type of hazard, antecedent conditions)
-Unprotected buildings
* Socioeconomic
-Lack of planning/prediction
-Hunger and disease
-Development of the country/amount of money
-Access to aid
-Their age or health (ageing pop)
-Population density
Ageing infrastructure
## Footnote
70% of people who died in Katrina were over 60, 56% of who died in Japan earthquake were over 65
56
What is Degg's model/what does it show?
* Degg's model shows the interaction between vulnerability, and nature
* The more vulnerable the population, the higher the risk for disaster
57
What can make a population vulnerable on a local and macro scale?
* Local
-Lack of skill
-Limited access to power
* Macro
-Rapid population change, and urbanisation
-Debt
-Exploitation of resources
-Failing systems
-Great reliance on water, power, technology and communications systems
57
How can risk be quantified?
* Risk = hazard x vulnerability
* Risk = (hazard x vulnerability) / manageability
58
How does resilience change between populations?
* Resilience can be increased if populations have the ability and resources to cope in times of need - therefore, populations can vary in resilience
* Generally, the more vulnerable you are, the less resilient you are
59
What is vulnerability?
* Capacity of a person or group to anticipate, cope with, resist and recover from the impact of a natural hazard
60
What can decrease vulnerability?
* Scientific understanding
* Government disaster assistance programmes
* Community initiatives
* Economic wealth
* Warning and emergency response systems
61
When was the Christchurch earthquake, what was it's magnitude, and where did it occur?
| Christchurch case study
* February 2011
* 6.3 on the richter scale
62
Why was there so much liquefaction in Christchurch, but not in the surrounding areas?
| Christchurch case study
- The epicentre was very close to Christchurch, so the shaking was much greater here
-The focus was also shallow
62
How much had the ground sunk?
| Christchurch case study
- In most places, it was up to 10cm (some places experienced more than this)
63
What was the February 2011 earthquake considered as?
| Christchurch case study
- An aftershock of the earthquake that happened six months earlier in 2010 (this had a higher magnitude, but caused less damage)
64
What were the factors affecting the impact?
| Christchurch case study
- Geology - there is lots of loose sediment (unconsolidated material) in this area
- Liquefaction
- Intense ground shaking due to: high energy levels released along the fault line, the direction the energy was released in, the shallow depth and close proximity of the epicentre
65
What were the impacts and responses?
| Christchurch case study
- The death toll was 184
- In the city centre, 80% of the water and sewage systems were destroyed
- The estimated cost of repairs was £8 billion
- 10,000 buildings needed to be demolished, and 100,000 repaired
66
What are components of a hazard resilience programme?
- Education
- Emergency plans
- Building design
- Landuse planning
-Modelling
- Risk assessment
-Monitoring
67
What were the characteristics of the volcano?
| Eyjafjallajokull case study
- Constructive plate boundary
- VEI of 3
- There is a glacier above the volcano
- 10km high ash plume containing sulfur
68
What was a the prediction and preparation?
| Eyjafjallajokull case study
- Warning signs
-Shallow earthquakes, deformation of the crust, minor eruptions
- Preparation: Diggers were positioned next to dam rivers, texts were sent to locals with a 30 minute warning, high river banks
- Around 15 eruptions of this scale usually happen each year in Iceland, so they are prepared
69
What were the responses?
| Eyjafjallajokull case study
- Immediate: 700 locals evacuated, exclusion zone created,
- Long term: River banks were rebuilt higher than before by the government
70
What were the social impacts?
| Eyjafjallajokull case study
- 700 people evacuated due to flood water
- The ash contaminated drinking water supplies
- Cancelled flights left many stranded
- Ash may have caused choking and respiratory illness
- Homes destroyed
- Crops destroyed
- Water supplies contaminated
- 5000 workers in Kenya laid off
71
What were the environmental impacts?
| Eyjafjallajokull case study
- The ash made Icelandic soil very fertile, farmers could produce rapeseed oil and grapes here
- Less aircraft noise, and 2.8 million tonnes less CO2 (due to grounded flights)
- Fluoride deposits on grazing land poisoned cattle
- Surrounding rivers silted with ash
72
What were the economic impacts?
| Eyjafjallajokull case study
- The ash plume caused problems for air travel for a week - 100,000 flights were cancelled
- Europe lost 2.6 billion USD of GDP
- Kenya lost millions from not exporting flowers etc
- Car manufacturers suspended production at some factories - difficulties accessing parts
73
How can resilience be increased?
* Good communications
* Medical services and supplies available
* Positive attitude of people
* Pre-planning
* Emergency procedures
* An inter grated infrastructure
* An unrealistic perception of the disaster
* Wealth of the nation
74
What can decrease resilience?
* Low doctor patient ratio
* Environmental degradation
* Large scale rural to urban migration
* A lack of skills
* Foreign debt payments
* Unequal fair trade agreements
* Rapid population growth
* An unrealistic perception of the disaster
* Wealth of the nation
75
What were the characterisitcs of the tsunami?
| Indian ocean tsunami 2004
* Earthquake of magnitude 9.1
* Seabed rose by 15m for over 1500km - 30m wave caused
* On a destructive plate boundary - Indo-Australian plate subducted under the Burma plate
75
What was the prediciton and planning like?
| Indian ocean tsunami 2004
* No tsunami warning system
* In many places, mangroves had been removed for economic reasons or tourism
76
What were the responses?
| Indian ocean tsunami 2004
* $14 billion USD provided in aid
* US provided aircrafts for search and rescue, surveying and transport of aid cargo
* Corruption hampered aid efforts
* A tsunami warning system was implemented
77
What were the economic impacts?
| Indian ocean tsunami 2004
* Many communities dependent on the fishing industry
* Infrastructure damaged - e.g. freshwater supplies
* Saltwater made the land infertile, and farmers counldn't irrigate
77
Were the impacts global?
| Indian ocean tsunami 2004
* Yes - 12 countries were affected, and the Earth's orbit was altered (days are now 2.68 microseconds shorter)
77
What were the social impacts?
| Indian ocean tsunami 2004
* Death toll: 228,000
* High population and tropical climate, so disease spread fast
* Drawback effect meant many people went to the exposed beaches - many drowned
78
What were the environmental impacts?
| Indian ocean tsunami 2004
* Coastal ecosystems e.g. mangroves destroyed
* Ecosystems polluted by human and chemical waste in the flood water
* Some small islands destroyed completely
79
What does the pressure and release model show?
* The progression of vulnerability
* Root causes -> Dynamic pressure -> unsafe conditions -> disaster <- natural hazards
79
What can root causes include?
* They create vulnerability
* Limited access to: power, structures, resources
* Political systems and economic systems
80
What can dynamic pressure include?
* Produce unsafe conditions
* Lack of: training, investment, press freedom
* Rapid population change
* Rapid urbanisation
* Deforestation
80
What can unsafe conditions include?
* Physical environment
* Local economy
* Social relations
* Public actions
81
What were the root causes?
| Haiti 2010 earthquake
* Haiti was forced to pay reperations to France in returnfor diplomatic recognition
-Had to borrow money to do this
* 80% live below the poverty line
## Footnote
Slaves in Haiti rebelled and defeated the French army (was their most valuable colony)
81
What were the dynamic processes?
| Haiti 2010 earthquake
* Little to no urban planning in port-au-prince to control settlement development
* Shortage of housing
* Housing is poor quality
* Agriculture policy fueled deforestation and soil degredation (from overfarming sugar plantations)
-Government lacked resources and will to change this
* Too poor to buy kerosene as bottle gas, so charcoal is used as fuel
82
What were the unsafe conditions?
| Haiti 2010 earthquake
* Uncontrolled illegal housing development in vulnerable areas - hillsides and floodplains
* Low GDP per capita - cheap materials and quick methods to build
* Roads are in poor condition - limited access, increase vehicle operating cost
* Limited access to water + sanitation
83
What were the root causes?
| Sichuan 2008 China
* Buildings were not built to withstand earthquakes
83
What were the natural hazards, and what did this lead to?
| Haiti 2010 earthquake
* 7.0 magnitude earhquake
* 316,000 killed
* 9 million affected
* Hundreds of thousands displaced
* Cholera epidemic
84
What were the dynamic processes?
| Sichuan 2008 China
* Schools couldn't withstand the earthquake
* Mud brick houses, and reinforced concrete buildings near the fault break
85
What were the unsafe conditions?
| Sichuan 2008 China
* Buildings damaged immediately, many collapsing (5 mil houses destroyed, 6 mil damaged)
* Classrooms collapsed - caused deaths of many children
* Landslides and shaking caused this
85
What were the natural hazards?
| Sichuan 2008 China
* 7.9 magnitude earthquake
* 80km away from magecity Chengdu
* Fault was 19km under and broke over a length of 240km
* Over 2 minutes of shaking
* 1700km away from epicentre in Shanghai, tremors were felt
85
What were the root causes?
| 2011 Tohoku Japan
* High populations in high risk areas
* Nuclear power plant on the coast
* Expensive infrastructure
86
What were the dynamic processes?
| 2011 Tohoku Japan
* Tsunami wall wasn't high enough
* Rural areas isolated for a while - destruction of transport routes
* Authorities considered economic benefits over safety factors
* Government didn't deal with power plant crisis
86
What were the unsafe conditions?
| 2011 Tohoku Japan
* Many people didn't listen to the tsunami warnings - to head for higher ground
* Seven reactors at the Fukishima nuclear power station had meltdown
87
What were the natural hazards, and what did this cause?
| 2011 Tohoku Japan
* 9.0 magnitude
* 30km deep hypocentre
* 3 minutes long
* 380km from Tokyo
* 130km by 159km rupture zone -pacific plate subduction zone
* Waves up to 40m
* 15,854 dead, 3617 missing, 26,992 injured
* 125,000 buildings ruined
* Blackouts for 4.4 mil buildings, 15mil buildings without water for 2 days
88
What are the characteristics of a mega disaster and what is the definition?
* A high magnitude, high impact event that affects several countries directly or indirectly
* Over 2000 deaths
* Over 200,000 made homeless
* GDP reduced by >5%
* Dependence on aid from abroad for a year or more after the event
88
What are advantages and disadvantages of the moment magnitude scale?
* Advantage
-Objective and scientifically effective
* Disadvantage
-Hard to understand the measure
-Doesn't describe impact
88
How is the moment magnitude scale measured?
* In terms of energy released
* Calculated from
-The amount of slip on the fault
-The area affected
-An earth rigidity factor
89
How is the richter scale measured?
* From the amplitude of waves recorded by seismographs
* Logarithmic - amplitude of magnitude 6 is 10x greater than 5
89
What are advantages and disadvantages of the richter scale?
* Advantage
-Objective
-Accurate
-Easy to understand
* Disadvantage
-Doesn't describe impact
90
How can the mercalli scale be measured?
* Done on an intensity scale - the effect of the earthquake
90
What are advantages and disadvantages of the mercalli scale?
* Advantage
-Includes impact, and effects to people
* Disadvantage
-Subjective
-No measure
91
How is the volcanic explosivity index measured?
* Relative scale so recent and historic eruptions can be compared
* Determined by:
-Volume of pyroclastic material ejected
-Height of eruption column
-Duration of the eruption
91
Why is a hazard profile used, and what criteria is it based on?
* To understand the physical characteristics of different hazards, and compare them
* Criteria:
-Frequency
-Duration
-Speed of onset
92
What is a multiple hazard zone and what are they used for?
* A hotspot, where plate boundaries interact with hydro-meterological factors in areas with hugh vulnerability
* To assess the risk of damage and death - historical data is combined with potential vulnerabilities e.g. population size
93
What human factors make the Phillipines vulnerable?
| Disaster hotspot - Phillipines
* Average income is 1415 USD and is a RIC
* Has a HDI of 0.78
* Has a population of 117 million
* Has a under 5 mortality rate of 40 per 1000
* Has annual popualtion growth of 2.3%
93
Describe the 2013 Bohol earthquake.
| Disaster hotspot - Phillipines
* 7.2 magnitude
* 20 aftershocks
* 222 dead, 976 injured
* >73,000 structures damaged, 38 million USD of damage to buildings, roads and bridges
94
Describe the 1991 Mount Pinatubo volcano.
| Disaster hotspot - Phillipines
* VEI 6 with a 7.7 earthquake the year before
* Hot ash, gas and giant mudflows
* Killed 1600, and injured 3
* 1.2 million homes lost, farmland and bridges destroyed
* Global cooling
* Lahars caused river bank erosion
* $700 millon USD in damages
95
How does the Phillipines prepare and manage volcanic hazards?
| Disaster hotspot - Phillipines
* Evacuations from accurate predictions (helped by US)
* Government shelters, and evacuation camps
* Storage of medical supplies, food and water in preperation
* Alert systems in place
* Permanent monitoring points set up, satellite images used to monitor volcanic site for land surface changes
96
How does California prepare and manage earthqauke impacts?
| Disaster hotspot - California
* Educate residents how to prepare e.g. keep food and water
* Construction and buildings must follow state building code
96
What natural factors make California vulnerable?
| Disaster hotspot - California
* On the conservative San andreas fault
* Earthquakes
-Tsunamis
* Hurricanes
* Droughts
97
What human factors make California vulnerable?
| Disaster hotspot - California
* Average income of 45,000 USD is a MDC
* HDI of 0.95
* Annual population growth of 0.7% -Population of 40 million
* Under 5 mortality rate of 7 per 100
* GDP per capita of $104,920
97
What natural factors make the Phillipines vulnerable?
| Disaster hotspot - Phillipines
* On the destructive Eurasion and Phillipine plate boundary in the Pacific ocean
* Has earthquakes and volcanoes
-Tsunamis, landslides, lahars
* Typhoons
-Flooding
* Droughts
98
Describe the 1994 Northridge earthquake in LA.
| Disaster hotspot - California
* 6.7 magnitude in San Fernando valley
* Thousands of after shocks of 4-5 magnitude in following weeks
* 57 died, over 1500 injured
* 12,500 buildings damaged
* 9000 homes and businesses without electricity and 20,000 without gas, 48,500 people without water
* Economic loss of $20 billion USD
98
Describe the 1989 Loma Prieta earthqauke in San Francisco.
| Disaster hotspot - California
* 7.1 in the Santa Cruz mountains
* Aftershock of 5.2 37 minutes after the main earthquake
* 63 died, 13,757 injured (most killed when the freeway collapsed)
* 1018 hoomes destroyed, 23,408 damaged, 366 businesses destroyed and 3530 damaged
* Economic loss of $6 billion USD
99
Why do MEDC's suffer more economic damages from hazards?
| Disaster hotspot - California
* They have more infrastructure/it is more expensive, so if it is damaged it costs more to rebuild
100
Why do LEDC's suffer more deaths and injuries?
| Disaster hotspot - Phillipines
* Tend to have a higher population
* Have less ability/resources and wealth to deal with the impacts
* Infrastructure not as developed so can be more easily broken
* Less prediciton and preperation in place
101
How can hazard profiles be used?
* You can compare different aspects of similar hazards
* Governments and other organisations use them to develop disaster plans
101
What is governance?
* The sum of many ways individuals and institutions, public and private, manage their common affairs
* It is a continuing process where conflicting interests may be accomodated, and co-operative action taken
102
What does governance include?
* Formal institutions and regimes empowered to enforce compliance as well as informal arrangements that people and institutions have either agreed to or percieve to be in their interest
103
What is economic government?
* Includes the decision making process about the economy and how it functions in the global economy
104
What is the administrative government?
* The system of policy implementation and requires good governance at all levels
-Requires the enforcement of building codes and risk mitigation strategies
105
What is political governance?
* Process of decision making including national disaster reduction
* Brings together different stakeholders to determine the quality of outcome
105
How can governance and natural disasters interact?
* Effectiveness of the economy
-Can't afford good training: less rescue: foreign aid needed
* Geographical isolation
-Country may be hard to reach: recieves less aid: people put at risk
* Political corruption
-Government takes money given as aid: less for the population
* Weak political organisation
105
What is the risk poverty nexus?
* Low income households and communities suffer a disproportionate share of disaster losses and impact
106
What is asset inequality?
* The uneven distribution of assests e.g. property among individuals or groups
* Agricultural productivity or goods and savings in trading communities
106
What is inequality of entitlements?
* Unequal access to public services and welfare systems
* Inequalities in the application of the rule of law - policing, judging and sentencing
107
What is political inequality?
* Exists worldwide in the unequal capacities for political agency - possessed by different groups and individuals in any society
107
What is social status inequality?
* Often directly linked to space and has a bearing on other dimensions of inequality, including the ability of individuals and groups to secure regular income and access services
108
How will asset inequality affect the population in a disaster?
* Creates inequalities, as some areas will be able to recover better than others
108
How will inequality of entitlement affect the population in a disaster?
* Different parts of the population may recieve different access to services, so some can recover quicker
109
How will political inequality affect the population in a disaster?
* Different groups may be prioritised - government may care more about certain groups/areas
* Unqualified people may end up in high up roles, and make decisions that aren't beneficial for everyone
109
How will social status inequality affect the population in a disaster?
* Leads to higher population density, more informal housing (more likely to fall down etc) - can cause disease to spread quicker
110
What can urban segregation lead to?
* Generate new patterns of disaster risk
* Low-income households may be forced to occupy hazard exposed areas
111
What were the human impacts?
| 2011 Tohoku Japan
* Over 16,000 died, and many were injured
* 450,000 people made homeless
* No returning to the area surrounding the plant for over 4 years
* 4.4 million households without electricity
* Rural areas isolated because of destroyed transport links
111
What were the economic impacts?
| 2011 Tohoku Japan
* Cost $235 billion USD
* 332,395 buildings, 2126 roads, 56 bridges, and 26 railways destroyed or damaged
* Oil refinery set on fire, nuclear power stations shut down - caused loss of power
111
What were the global impacts?
| 2011 Tohoku Japan
* Nuclear energy supplied 30% of energy in Japan
* LNG cargos diverted to Japan to fill gap
* Led to higher demand for LNG, so prices rose in other countries
| Liquefied natural gas
111
Why do some magacities have low hazard resilience?
* High population density - rapid destruction and high loss of life
* Raoid growth and inadequate planning - poor people settle illegally in hazardous areas
* Ecological imbalance as rapid urbanisation destroys ecosystems
* Dependency on infrastructure and services
112
What did Haiti do to prepare/prevent disaster, and how did they respond/recover?
| Haiti 2010 earthquake
* Minimal ways to prevent
* Minimal ways to prepare
* Countries and NGO's sent aid
* Minimal government response - bad state of the government
113
How did Japan prevent and prepare for disaster?
| Tohoku 2011 earthquake
* Prevention:
-Earthquake proof buildings
-Sea defences wall
-Evacuation plans and warning system
-Education for communities
* Preparedness:
-Had prediction systems, so there was time to prepare
-Evacuations
113
How did Japan respond to and recover from disaster?
| Tohoku 2011 earthquake
* Respond:
-Search and rescue teams
Evacuated at risk areas for long periods of time
* Recover
-Rebuilt sea walls higher
114
Why doesn't planning always work?
* The event can be underestimated
* Planning may be outdated
* Planning may not be good
115
What is relief?
* Activities implemented after the impact of a disaster in order to:
-assess the needs
-reduce the suffering
-limit the spread and the consequences of the disaster and open the way to rehabilitation
116
What is resilience?
* How a community is able to adapt and recover
117
What happens in an emergency?
* Normal procedures are suspended and extra-ordinary measures are taken to deal with a disaster
118
What is the hazard management cycle?
* Links the before and after of the event (event in the middle)
* Includes:
-Prevention, mitigation and preperation (before)
-Response and recovery (after)
118
What is the risk disc?
* Shows that risk reduction is made up of many parts
-Disaster recovery
-Disaster response
-Disaster mitigation
-Development
-Disaster preparedness
-Adaptation to climate change
119
What does the park hazard response model show?
* How a hazard affects normality over time
-Pattern of change in various indicators at different phases of the hazard, with the overall trend of recovery towards normality
* On the bottom: pre-disaster -> relief -> rehabilitation -> reconstruction
120
Whatare the pros and cons of the Park hazard response model?
* Pro
-Useful to compare different events (curves can be drawn and compared on the same graph)
* Con
-Model does not account for different levels of development and other issues affecting disruption ad recovery
120
What happens during relief, reconstruction and rehabilitation?
| Park hazard response model
* Relief: immediate
-Saving lives and property
* Rehabilitation:
-Temporary housing and services
* Reconstruction
-Restore quality of life and economic stability
-Reducing vulnerability
-Can lead to improvement or return to normality
121
How might individuals respond to a disaster?
* Search and rescue
* Undertake recovery steps
* Implement following strategies
122
How might national governmnets respond to a disaster?
* Organising
-Emergency aid
-Short term aid
-Long term aid
122
How might local government respond to a disaster?
* Evacuation routes/plans - implementing plans
* Land use zoning
* Community organisation and well-being
* Monitoring the law
* Providing aid
123
How might international organisations respond to a disaster?
* Providing funds/financial aids
* Co-ordinate search and rescue efforts
* Help to develop reconstruction plans
123
What is mitigation?
* Avois, delay, or prevent hazard events
124
What is adaptation?
* Reduce the impactsof hazard events
125
What is land use zoning, and what are its pros and cons?
* Prevention of building on
-low lying coasts
-Where liquefaction is likely
-Near volcanoes
(hazard maps are used to determine)
* Benefits:
-Low cost
-Relocates people from high risk area
* Issues:
-Prevents economic development in some coastal areas
-Requires strict enforcement
126
What are the pros and cons of a seismic buildings?
| e.g. deep foundations, counter weights, or cross bracing
* Benefits:
-Protects people and property
-Financially possible in developed countries (basic design replicated in developing countries)
* Issues:
-High costs for tall buildings
-Older buildings and homes for people on low incomes are difficult to protect
127
What technology can be used in hi-tech monitoring?
* GIS
* Early warning systems - detect hazards, and warn people
* Satellite communication technology - monitoring
* Mobile phone technology - for alerts
127
What are the benefits and issues of tsunami defences?
| Building sea walls and breakwaters
* Benefits:
-Reduces damage and provides a sense of security
* Issues
-Can be overstopped
-High cost
-Unsightly
127
What are the benefits and issues of lava diversion?
| e.g. digging channels, water cooling, barriers
* Benefits
-Diverts lava away from people and buildings
-Relatively low cost
* Issues
-Only works for basaltic lava
-Not feasable for the majority of explosive volcanoes
-Path taken by lava is hard to predict
-Terrain has to be suitable
128
How is GIS mapping used in hazard management?
* Used in all stage of the hazard management cycle
* Identify where evacuation routes should be placed
* Creates hazard management maps
-Locations of airports
-Populations and locations of towns and cities
-Areas affected by earthquake
* Help aid find the most affected areas, and where aid can be delivered
129
What are the benefits and issues of hi-tech monitoring?
| Monitor volcanoes and predict eruptions etc.
* Benefits:
-Prediction is quite accurate
-Warnings/evacuations save lives
* Issues
-Costly
-Cry wolf syndrome
-Damaged property
130
How does crisis mapping help hazard management?
* Information provided by locals and plotted online by volunteers
-Rescue/aid workers know where to direct resources
* Crowd sourced info and satellite imagery used
* Aid agencies have started uing this before disasters
131
How does modelling a hazard impact help hazard management?
* Computer models mean scientists can predict the impacts of hazard events on communities
-Compare effects of different scenarios
* Develop plans and strategies to reduce the impact of hazard events, and target resources effectively
132
What does public education involve?
| Teaches what they can do to protect themselves in a hazard
* Regularly practicing emergency procedures
* Encouraging work and households to create emergency kits
* Provide effective education materials, e.g. info on constructing buildings to withstand earthquakes
132
What does community preparedness and adaptation involve?
* In LIC's governments may not have resources to invest in disaster planning/reach all communities
* Governments may help communites to
-Create a list of vulnerable people
-Organise practice evacuation drills/prep days
-Provide first aid courses
-Earthquake kits
-Risk education
133
What are the benefits and issues with community preparedness?
* Benefits:
-Low cost (NGO's may organise)
-Saves lives at a local scale
* Issues:
-Property is still damaged
-Harder to implement in isolated rural areas
134
What are the benefits and issues with relocating?
* Benefits:
-Saves lives and property
* Issues:
-Difficult in densely populated areas
-Disrupts peoples lives
135
What can aid donors provide?
* Emergency aid (food, water, shelter)
* Short term aid
* Long term aid (rebuilding infrastructure etc)
* Can be cash, personnel, services or equipment
136
What can insurers do in hazard management?
* Individuals and businesses get money they need to repair and rebuild
* Not available or unaffordable in many developing countries
136
What can NGO's provide?
* Search and rescue teams
* Water
* Shelter
* Food and clothing
* Medical care
* Remove debris
* May build more permanent shelters
* Provide funds, searches and reconstruction plans
* Involved in all stages of the hazard management cycle - remain in affected area for a long time
