tectonic hazards and processes

Micro approach to improving protection from earthquakes
Quake- proof buildings
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Four types of plate boundary
Convergent, divergent, conservative, transform
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Two plate boundaries where most powerful earthquakes occur
Convergent, conservative
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Two plate boundaries where most volcanoes occur
Divergent, convergent
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How do hotspot volcanoes occur?
Crust above magma plume is weak, magma leaks through
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Example of hotspot volcanoes
Hawiann islands
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Characteristics of oceanic plate
Thin, light, made of basalt
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Characteristics of continental plate
Thick, heavy, made of granite
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Cause of plate movements
Convection currents in mantle causing slab pull
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Three processes at work on destructive plate boundary
Subduction, mountain building, volcanic & seismic activity
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What paleo-magnetism is
When cooling magma locks into earths polarity
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How paleo-magnetism helps study of tectonics
Can work out; when there were large tectonic activity in geological history, directions and speeds of past and current plate movements
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Example of a locked fault causing a tectonic hazard
2004 Indian Ocean tsunami
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Why locked faults occur
The friction along the plate is greater than the stress across it
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What the Benioff zone is
Oceanic plate subducted under continental plate > stress=earthquakes > within this zone oceanic plate is melted
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Manifestation, directly above hypocentre
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Magnitude of earthquake
Amount of displacement of crust & amount of energy released
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Intensity of earthquake
Amount of ground shaking
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Three types of seismic waves
(1)P-waves: vibrations caused by compression, spread quickly, (2)S-waves: vibrations at right angles to direction of movement, slower, (3)L-waves: surface waves with high amplitude
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Secondary hazards of earthquakes
Tsunamis, landslides, liquefaction
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Liquefaction definition
Where sands, silts, and clays loose their load bearing capacities
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Primary volcanic hazards
Lava flows, tephra, ash clouds
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Glacial outburst floods caused by volcanic eruption occurring under ice sheet/ glacier
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Key areas of globe affected by tsunamis
Pacific basin, Japan - Taiwan island arc, South America, Aleutian islands
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Hazard risk equation
(hazard x vulnerability) / manageability
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What vulnerability means in regards to hazards
The likelihood of a community being unable to recover from the affects of a hazard
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What resilience means in context of hazards
How well a community can deal with the affects of a hazard
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What makes a hazard into a disaster
When a hazard causes significant damage and destruction to a vulnerable population
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The two pressures on the Pressure and Release model
Natural hazard event & vulnerability of people experiencing hazard
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Scales used to measure earthquakes
Richter, Mercalli, MMS (moment magnitude scale)
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Measures amplitude of eathquakes shock waves
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What VEI measures
Volcanic Explosivity Index measures volume of material ejected, height of eruption cloud, and other qualitative observations
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Six characteristics in hazard profile
1)speed of onset, 2)magnitude, 3) areal extent of damage, 4)duration, 5)freqency, 6)predictability
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Value of hazard profiles
Comparisons can be made, informs decision making in hazard planning to identify factors such as level or risk and scale/ impacts.
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Inequalities causing low income communities to be affected worse
Less money to recover, access to services inequality; education, health care, policing etc. Political inequality, social status inequality
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How poor governance increases vulnerability
People uneducated on response, lack of investment in infrastructure, inadequate transport links, inadequate mitigation strategies.
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Why disaster statistics aren't altogether reliable
(1) Governments lying = more aid (2) Commercial bias = downplayed in tourist areas (3) Disasters unrecorded due to remoteness
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Characteristics of mega disasters
(1) Huge damage to infrastructure/ loss of life, (2) Large economic impacts, (3) Likely to need international support, (4) High impact, low probability
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Example of tectonic mega disaster
Asian 2004 tsunami
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Why there is concern over world's rapidly growing mega cities
Located in hazard prone/ multiple hazard zones , Sheer population size and density = severe impacts
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Four stages of hazard management cycle
Mitigation - Preparedness - Response - Recovery -
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What the risk disk model attempts to explain
Decline in disaster deaths in terms of preparedness, mitigation, response & recovery
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Role of scientists in dealing with tectonic hazard
Seismologists - Predict WHERE and when earthquake could occur , Volcanologists - Predict WHERE and WHEN eruption could occur
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Human factors affecting response
Education, quality of emergency services, quality of infrastructure/ transport links, population density
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The four stages of Park's model
Pre-disaster - Relief - Rehabilitation - Reconstruction
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How Park's model helps study of tectonic disasters
Compares two or more curves, Better understanding of their relative resilience, Help plan and understand risk, Places at risk to better prepare
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Micro approach to improving protection from volcanoes
Spraying water on lava flows
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Macro approach to protection from tsunamis
Tsunami wall, land use zoning, coastal buffers (mangroves)
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Role of planners in managing impacts of tectonic hazards
Modifying potential impacts of event (land use zoning, improving prediction/ early warning systems) Improving preparedness (emergency action plans, education)
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Role of insurers in managing impacts of tectonic hazards
Reduce financial burden - only for those who can afford insurance premium - no use to poor
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Role of non-governmental organisations in managing impacts of tectonic hazards
Most active during emergency phase - providing various forms of aid. Educating about hazard risks & response
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Four approaches to hazard management
1) Modify loss 2) Modify vulnerability 3) Modify the event 4) Modify the cause
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How to modify loss
Aid and insurance
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How to modify vulnerability
Improve prediction, preparedness, educate public on response
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How to modify the event
Land use zoning, construct hazard resistant buildings, strengthen defences
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How to modify cause
Not really possible, only on small scale hazards such as landslides
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How to evaluate approaches to hazard management
1) Feasibility 2) Cost 3) Effectiveness 4) Type of hazard
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japan earthqauke/tsunami 2011
>magnitude of 9.0 >paciifc plate sliding underneath North american plate
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effects and responses of japan earthqauke/tsunami 2011
EFFECTS=16,000 killed, 12 countries effected, 230,000 people who lost their homes , Ports and airports in Sendai were damaged and closed. RESPONSES= seawall bulilt but the tsunami was too powerful and went past it,tsunami warning system put in place
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Indian ocean (2004
subduction of the Indo-Australian plate(oceanic) under the Eurasian plate(continental)
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effects and responses of Indian ocean (2004) earthquake/tsunami
EFFECTS=220,000 people killed,1.7M people displaced, countries such as india.maldives and thailand effetced RESPONSES=warning system, action aid>£13M
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Haiti earthquake
the North American Plate sliding past the Caribbean Plate at a conservative plate margin
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effects and responses of haiti earthquake
EFFECTS=316,000 people died, 3M affected, 4,000 prisoners escaped, hospitals & schools damaged RESPONSES=810,000 people in aid camps, water and saniations given to 1.7M people
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mt st helens
near to a destructive plate boundary where the small Juan de Fuca Plate is being sub ducted underneath the North American Plate.
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effects and responses of mt st helens eruption
EFFECTS=15cm ash fall leading to trafic chaos, mudflows choking up rivers and killing sea life, 7000 animals dead, less tourism, 57 people dead RESPONSES=aid protection, providing shelters, medical supplies
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mt pinatubo
located at the plate boundary between to the Eurasian and Philippine Plate.
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effects and responses of mt pinatbo
EFFECTS=847 died,300 killed by collapsing roofs and 100 by lahars,1.2m people lost their homes RESPONSES=barriers,diversions of lava flow, 58,000 evacuated
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other case studies
hawaii islands, mt etna, phillipines, Eyjafjallajokull Eruption - 2010,
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Other cards in this set

Card 2


Four types of plate boundary


Convergent, divergent, conservative, transform

Card 3


Two plate boundaries where most powerful earthquakes occur


Preview of the front of card 3

Card 4


Two plate boundaries where most volcanoes occur


Preview of the front of card 4

Card 5


How do hotspot volcanoes occur?


Preview of the front of card 5
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