tectonics Flashcards
What is the general distrubution of volcanoes?
There are around 1500 active volcanoes on earth, most occuring along plate boundaries. About 50 of them erupt every year.
What is the global distrubtion of tsunami events?
90% of all events have occured in the pacific basin, especially off the Japan-Taiwan Island arc. They normally occure along convergent plate boundaries.
what causes an earthquake?
Subduction zones are broad areas where two plates are moving together, often with the thinner, more dense oceanic plate descending beneath a continental plate. The contact between the plates is sometimes called a thrust or megathrust fault. Where the plates are locked together, frictional stress builds. When that stress exceeds a given threshold, a sudden failure occurs along the fault plane that can result in a ‘mega-thrust’ earthquake, releasing strain energy and radiating seismic waves. It is common for the leading edge to lock under high friction. The locked fault can hold for hundreds of years, building up enormous stress before releasing. The process of strain, stress and failure is referred to as the elastic-rebound theory.
The 2004 Indian Ocean tsunami was the result of a mega-thrust locked fault (subducting Indian Plate) with strain building up at around 20 mm per year. It generated huge seismic waves and the devastating tsunami.
What are the three major types of plate boundary?
Convergent, divergent and conservative
What happens at a convergent plate boundary where an oceanic and continental plate meet?
As oceanic plates are denser than continental plates, the oceanic plate gets subducted underneath the continental plate when they collide. The oceanic plate begins to melt as it enters the mantle, which forces itself to the surface in the form of magmatic plutons through faults in the lithosphere to form explosive volcanic eruptions due to the high silica content in the oceanic plate. Deep ocean trenches mark where the oceanic plate was subducted. The subduction leads to the formation of fold mountains as the continental plate is folded and pushed upwards. Friction in the subduction causes deep earthquakes in an area known as the benioff zone. E.g the Nazca plate under the South American plate, forming the Andes.
What happens at a convergent plate boundary where two oceanic plates meet?
The oceanic plate which is moving faster or is denser tends to be subducted, forming oceanic trenches. Magma is created from the subduction, which escapes from the mantle to the ocean floor through faults in the crust. The creates underwater volcanoes which overtime will reach the surface to form island arcs such as Hawaii. Subduction also causes earthquakes (this was responsible for the 2004 Indian ocean tsunami)
What happens at a convergent plate boundary where two continental plates meet?
No subduction occurs at first as the two plates have very similar properties. Instead, they collide and crumple upwards, forming fold mountains. Overtime some subduction may occur when sediment is compressed and becomes denser. No volcanic activity as no magma is created, but shallow focus earthquakes which increases severity as energy is not dissipated through the crust.
What happens at a divergent plate boundary?
In the ocean, two plates separating depressurizes the asthenosphere, causing partial melting and magma to escape and cool, forming underwater volcanoes the Mid-Atlantic ridge - new crust is created to ‘fill in the gaps’. Islands can form like Iceland. When plates move apart on land, the crust cracks and forms faults, before it eventually collapses, forming rift valleys
What happens at a conservative plate boundary?
Two plates move past each other, often snagging as they move causing major cracks in the crust known as faults. If these continue to grow, they are known as transform faults. No magma is created, nor crust made or destroyed. However, powerful, shallow focused earthquakes occur. EG the san-andreas fault in California.
What tends to be the most severe plate boundary?
convergant, due to th existence of mega thrusts, the stress and tension built up tends to be far more severe than conservative and divergent boundaries
What causes a intra-plate earthquake?
The reactivation of ancient fault lines, caused by changes in the stress pattern across the lithosphere.
What is the general distribution of earthquakes?
Around 95% occure along plate boundaries, with 70% occuring in the ‘Ring of Fire’ in the pacific. Arounnd 5% are intra-plate earthquakes.
What causes intra plate volcanoes?
Mantle plumes below faults in the crust.
What is the structure of the earth?
What are the main processes that move plates?
Mantle convection - radioactive decay in the earths core generates heat, which heats the lower mantle, and creates convection currents within the mantle, causing plates to move (disputed)
Sea floor spreading - the spreading of sea floors creates mid ocean ridges, which become denser as they cool. Overtime, they will sink into the lithosphere, dragging the plate down with it. This is known as slab pull
subduction - gravity causes dense oceanic plates to sink when colision occures.This pulls the rest of the plate down with it.
What are the pieces of evidence that proved plate techtonics?
Studies during the 1950s highlighted paleomagnetism along mid ocean ridges. When scientists surveyed the mid ocean ridges, they found symetrical bands of magnetic stripes. This is due to the fact that every 400,000 years the earths magnetic field swaps, and the iron in newly fomed magma alligns itself to the earths polarity. The existence of symetrical bands of rock proved that new crust was being created through sea floor spreading.
Further analysis showed that the coninents use to fit together but became distant due to continetal drift. Further more, fossils of animals match across the continents, proving the existence of pangea.
- What is the Benioff zone?
- What is the hypocentre/focus?
- what is the epicentre?
- The planar zone of seismic activity which corresponds with the subduction of a plate
- The hypocentre/focus is the point within the point where an earthquake rupture starts - this is the point where seismic waves are emmited from
- The epicentre is the point ton land directly above where the hypocentre/focus is
What is signifcant about how deep/shallow the benioff zone and focus are?
The deeper the focus and benioff zone, the longer the energy from the earthquake can disipate before reaching the surface. Therefore, a shallow earthquake, even if it releases the same amount of energy as a deep earthquake, will have more adverse effects on a population.
Explain each of the 3 different waves emmited from an earthquake
- (P)rimary waves - These are compressional waves, and travel at 8km/sec, and therefore are the first to arrive. They cause the least damage and travel through solid and liquids.
- (S)econdary waves - These are slower, travelling at 4km/sec. They osicilate at right angles to the direction of travel. They only travel through solids. They cause more damage than P waves
- (L)ove waves - only travel through the surface, and shake the ground from side to side. They are the slowest, but cause the most damage as all their energy is focussed on the surface, and they have a greater amplitude.
What are the primary hazards caused by an earthquake?
- Ground shaking - when the release of seismic waves, mainly L waves, causes the ground to shake, destroying buildings
- Crustal fracturing - When Seismic waves create faults in the earths crust, causing gaps to appear
What are the secondary effects of an earthquake?
Liquifaction - the violent shaking of the earth causes saturated materials to behave like a fluid, which destablises infrastructure. In the 1995 Kobe earthquake, the container terminal was destroyed by liquifaction due to the destabloised ground.
Landslides - Shaking of the ground destablises sediment on an incline. In the 2015 Nepal earthquake, The Langtang village was covered by a landslide, killing 178 people.
Tsunamis (get to later)
What are the three forms of lava? What type of volcano do they create?
- Basaltic - low silica (50%) and gas content, therefore has a low viscosity meaning gasses can escape. This means eruptions are fairly gentle, and this type of magma creates sheild volcanoes
- Andestic - Medium silica (60%) and gas content
- Rhylotic - High silica (70%) and gas content
These types of lava trap gasses, and therefore eruptions are far more explosive and dangerous. These tend to be found at convergant plate boundaries
What are the primary affects of a volcano?
- Lava flows - streams of lava erupted from the volcano. These tend not to be too dangerous as most people can outrun them, however can cause devistating affects on buildings and agriculture
- Pyroclastic flow - the most dangerous affect of a volcano. These when a mixture of hot gasses pyroclastic materials like ash and glass flow down volcanoes in a cloud. These can be 1000c and travel at 700km/h
- Tephra - the eejection of fine material (ash) into the atmosphere. This can build up on roofs and cause themm to colla[se, and can also reduce visibility and air travel.
- Volcanic gasses - emit fromvolcanoes, and can be undetected by people becuase they are colourless and odourless. in 1986, emmisions of Carbond dioxide from Lake Nyos in Cameroon killed 1700 people, as it sat over there village.
What are the secondary affects of a volcanic eruption?
Lahars - When tephra deposites mix with heavy rainfall to form mudflows
Jökulhlaups - A devestating flood caused by glacial meltwater. Here, a volcanic eruption melts the bottom of a glacier, causing meltwater to form underneath the glacier. When enough meltwater is formed, it will lift away the ice block and escape from the volcanic crater, causing serious flooding in the surrounding area
What causes a tsunami and what are they?
A tsunami is a series of larger than normal waves.
They are caused, usually, by megathrust earthquakes at convergant plate boundaries. The megathrust of a the subducting plate causes the sea floor to be displaced, sending massive amounts of energy vertically via a water colomn. Once this reaches the surface, the energy spreaded out laterally via waves, which at first are hard to notice due to their low amplitude and wave length. It is only when they reach the coast, where friction of the coast compresses the energy and forces it to rise, causing a very large series of waves.
What is the difference between a natural hazard and a disaster?
A natural hazard are natural processes or events that have the potential of negatively affecting people
On the other hand, a disaster occures when a natural hazard meets a vulnerable population, and causes severe social economic and enviromental affects which exceeds a populations capacity to cope using their own resources.
Thus, the occurance of a natural disaster is the interaction of human and physical systems. This is knowns as Deggs model
What is the hazard risk equation? Explain its component
Risk = Hazard x vulnerability / capacity to cope.
* The hazard is the severety of the natural hazard itself, like it’s magnitude, duration when it occurs etc…
* The vulnerability of the population are the conditions that exist that increase the sceceptability of a population from suffering from a natural hazard
* the capacity to cope is the ability of people, organizations and systems, using available skills and resources, to manage adverse conditions.
What is the PAR model and what are its three components?
The Par model is a tool used by planners to assess the vulnerability of a community.
1. Root causes - The underlying, systemic factors in society which influence distributions of power and resources - eg corruption
2. Dynamic pressures - the actions that occure as a result of the root causes which lead to
3. Unsafe conditions - the conditions that are present in society that directly put people in more risk of natural hazards
The model attempts to explain how an underlying condition in society leads to outcomes that are not the same thing, but are often connected.
describe the hazard profile for the Haiti earthquake?
On 12th of January, a 7.0 magnitude earthquake struck haiti close to the capital Port Au Prince, the epicenter was just 24km away. It had a shallow focus of just 13km and caused widespread liquefaction
What made Haiti vulnerable?
- poorest country in th western hemisphere, 80% of the population earns less than two dollars a day (government does not have a fiscal dividend
- Heavely indebted to France historically and the world bank currently, meaning the government used money to payy off debt rather than investing in infrastructure
- Corruption, meaning building regulations were not followed as government officalsaccpted bribes by builders to cut corners, created unsafe conditions in the form of poorly constructed buildings which easily collapse under ground shaking.
What where the impacts on Haiti?
- Airports and ports became damaged, slowing responses
- 25% of civil servants died
- 160,00 dead (government claims 220,000 but this is likely inflated)
- 1.5 million homeless
What were the responses to the Haitian earthquake and what does this show?
- 13 billion dollars of aid given - shows that haiti is especially vulnerable due to its low capacity to cope using its own resources, and is reliant on outside help
- The death of government officials made haiti especially incapable of coping with the affects due to the lack of administrative officials able to organise a response
- Government ocrruption was a concern so only 10% of Aid was controlled by the government
- Tempory housing was poor - Damages to sanitation caused outbreaks of cholera killing 9000 people
What can be learnt from the Haiti earthquake
Vulnerability in communities, caused by economic and social factors, can cause a fairly normal earthquake into a mega disaster. Poverty can cripple a governments ability to respond to a hazard, aswell as creating conditions which can cause disaster in the first place. A lack of effective government can mean ecconomic resources go to waste.
What was the hazard profile of the 2008 Sichuan earthquake?
ON the 12th of may 2008, a 7.9 magnitude earthquake hit South Western China.
What affected Sichuan vulnerability? Why was it less vulnerable than Haiti
- Building regulations, like in Haiti, were not followed due to local government officals acceepting bribes. created unsafe conditions in the form of poorly constructed buildings which easily collapse under ground shaking.
- However, it was a rural area of China and thus not desnsely populated
- wealthier than haiti, being a NEE rather than a LIC
- Strong national govvernment.
What where the affects of the earthquake
69,000 died
5335 school children died, due to collapsing school buildings
What was the response to the earthquake
- 130,000 national troops were sent to affected regions within 24 hours
- Chinese government pledged 10 billion dollars to rebuild affected communites
What can be learnt from the earthquake
Shows a clear pattern that neglect from a local government creates communities which are vulnerable. However, strong national government was able to respond quickly and effectively.
What was the hazard profile of the 2011 Tohoku earthquake
On the 11th of March 2011, a 9.0 megathrust Earthquake occured, about 100km from the Japanese coast.
Why was Japan more prepared for earthquakes?
- Japan is a very economically developed country, meaning the government had the financial resources to invest in infrastructure and respond to the hazard
- 75% of buildings are built with earthquakes in mind
- Education - children are taught in schools tsunami and earthquake procedures
- Tsunami walls reduced some impacts
What were the affects of the earthquake and tsunami?
19800 dead, 56% were elderly
$220 billion in damages
Meltdown of Fukishima forced evacuations and an exclusion zone still exists today - enviromental ruin due to radioactive contamintion
What were the responses to the earthquake?
110,000 troops mobilised
$250 dollars pledged to rebuild
government subsidised nuclear research to reduce risk
What can be learnt from the event?
That, even though the event was significanty more intense than in Haiti, the death toll was minute compared to it. However, deaths still occured, as in the face of such a severe hazard human preparedness can only do so much to reduce loss of life.
What was the hazard profile of the Indian ocean tsunami?
9.0-9.3 magnitude earthquake occured on th 26th of December 2004. It megathrust moved the Indian ocean sea floor 15 meters towards Indonesia, sending shockwaves as it did. 17 meter high tsunami.
What affected the vulnerability of the region?
Many low income communities, which were more vulnerable to the affects due to limited infrastructure and capacity to cope using their own resources.
In addition, there was no tsunami early warning system installed in the Indian ocean, meaning communites had no time to prepare tpo the hazard and where caught by suprise.
What were the affects of the tsunami?
- 290,000 dead
- 1.7 million left homeless
- $10 billion in damages
- Thai tourism industry lost 25 million in revenue every month
- 1500 villages in Sumatra completely destroyed.
What can be learnt from the hazard?
- Desnely populated regions - poverty and over population creates unsafe conditions
- removal of mangroves for tourism decreased natural barriers of the tsunami
- Natural hazard was so severe due to the lack of a warning system - took communities off guard
- Area fairly impoverished so lack of infrastructure and emergancy services.
What was the hazard profile of the Eyj volcanic eruption?
2010, eruption of icelandic eruption. 8km high ash cloud following a VEI of 4.
What where the effects of the eruption?
100,000 comerical flights cancelled, costing airlines 1.7 billion in lost revenue
Kenyan farmers lost 1.3 million in agricultural revenue a day.
What was the hazard profile of the Pinatubo eruption?
June 1991 in the Philippenes. Vei of 6.
Pyroclastic flows filled valleys with volcanic deposists 200m deep
What were the impacts of the eruption?
847 dead
20,000 evacuated
Release of 17 megatons of sulfur dioxide into the atmosphere
What were the responses to the hazard
615 million pesos was spent on the agriculture development program.
UNDP gave 50,000
What can be learnt from MT Pinatubo eruption?
- accurate prediction and forecasting saved 10,000s of lives through evacuation - this requires a strong response though
- rural area it erupted in reduced death toll
- Could be argued that extreme hazards can be sucessfully managed
What 5 reasons explain why people continue to live in an area at risk from tectonic hazards?
- May be unaware of the true extent of the risk
- May live in poverty so have no alternatives to move away
- The risk of hazards come and go - some people may simply be unluckky if caught by an execptionally rare hazard
- The benefitss may have outweighed the risk, eg agricultural productivity
- One may just accept that such natural hazards are a part of life
What are the two ways scientists measure earthquakes?
Magnitude or intensity
* Moment magnitude scale - Magnitude
* Modified Mercalli intensity scale - intensity
What is the moment magnitude scale?
Logarithmic scale which measures the amount of energy released at the seismic moment
What is the Mercalli scale?
A measure based off the effects of an earthquake on people and the enviroment (therefore is subjective). It ranges from I - XII
What is the VEI
A measure of the magnitude of a volcano, ranging from 0-8. It is a composite index, using a range of factors such as the volume of tephra emmited, length of eruption etc…
What are hazard profiles?
A graph which compares the physical processes and characteristics that all hazards share, eg the magnitude, speed of onset and the duration
Why are hazard profiles used? Give an example?
They help decision makers develop disaster plans which are based off the characterisitics of similar hazard events - for instance, the hazard profile of the 2004 Indian ocean tsunami shows a high magnitude and exten, with a rapid onset. Planners may use this to identifiy the need for an early warning system.
What are four inequalities which influence resiliance and vulnerability that are tied with levels of development?
- Levels of education
- access to quality housing
- access to healthcare
- levels of income
How does inequality in education influence vulnerability?
populations with better access to educational resources are more likely to understand the science behind earthquakes, volcanic eruptions, and tsunamis, as well as safety measures such as evacuation procedures, emergency planning, and first aid.
Spatial disparities in education can leave certain communities unprepared. Inadequate disaster education in low-income or rural areas, where education systems may be underfunded, leads to greater vulnerability in the face of tectonic hazards. Populations without knowledge of proper evacuation routes or structural weaknesses in buildings are at higher risk during a tectonic event. In contrast, communities with higher education levels tend to have better disaster literacy, which enhances their adaptive capacity during and after a tectonic disaster.
Long-term resilience is also enhanced when the education system integrates disaster risk reduction (DRR) programs, fostering a culture of preparedness and recovery in future generations.
How can inequality in housing influence vulnerability? Where can this be seen?
Housing quality is one of the most critical factors determining vulnerability during tectonic events. In earthquake-prone areas, for instance, poor housing construction increases the likelihood of structural collapse, leading to a higher death toll and more severe injuries. Informal settlements, where buildings are often constructed with inadequate materials and without seismic resistance, are particularly vulnerable. These areas experience housing precarity in the form of substandard, overcrowded living conditions, which exacerbate the impact of tectonic hazards. In addition, the collapse of buildings reduce the effectiveness of rescue efforts, as well as increasing mortality. 5334 school children died in SIchuan 2008 due to poorly regulated buildings. Inequality in housing can be down to development - some communities may lack the funds to build adequte housing, it can also be down to governance - if the government is corrupt, they may accept bribes and take short cuts in construction.
How can inequalities in healthcare influence vulnerability?
Access to healthcare is fundamental in mitigating the impacts of a tectonic hazard. In the aftermath of an earthquake or volcanic eruption, healthcare systems are often overwhelmed due to the number of injured individuals and the widespread need for medical care. Communities with poor healthcare infrastructure are less able to provide emergency services, leading to higher mortality rates and slower recovery. The lack of healthcare accessibility in areas with weak or underfunded medical facilities increases the vulnerability of affected populations.
Vulnerability is also tied to health disparities. Populations that are already dealing with chronic health conditions or limited access to medical treatment are more likely to suffer during and after a tectonic hazard.
How can inequalities in income influence vulnerability?
Income directly affects the level of economic development a country experiences, and thus is a fundemental facotr which links to all others. Wealthy countries will have a greater fiscl dividend which they can use to invest in quality infrastructure to reduce vulnerability, but also to be able to foster a more effective response scheme so increases capacity to cope.
How does governance influence vulnerability
A strong government will be more able to allocate resources effectively in reducing risk or mitigating the ipacts of tectonic hazards. They can use financial resources to enforce building codes, aswell as investing in quality healthcare and education. In additon, a strong government will be more able to co-ordinate aid and responses immediately after an earthquake and the long term rebuilding. IN contrast a weak government will be corrupt, not follow buidling regulations which creates unsafe conditions, and will allocte resources less affectively in the afermath
Why does level of development influence vulnerability
- Government may have other short term priorities - disease or hunger prevention, paying off debt
- Wont have the fiscal dividend required to reduce vulnerability through mitigation and adaptation stratergies
- will be less self reliant, reducing capacity to cope using own rrsources so is reliant on foreign aid which can take time to arrive
How does population density and urbanisation influence vulnerability?
- urban sprawl = a higher concentration of vulnerable people and infrastructure
- If not regulated properly, this growth will occure without the proper risk reduction techniques
- Responses will be slower
- Building collapses will result in greater mortality
What has been the trend in the number of deaths, number of affected and level of economic dmage from tectonic hazards? How does this differ from natural disasters?
Deaths and numbers affected have stayed fairly constant- they remain steady and flucute every few years due to a significant tectonic disaster, with a slight downwards.
Economic damage has increased as the world has become more developed
On the contrary, the number of natural disasters keeps on rising.
Why have the number of natural disasters been increasing?
- The increase in monotoring technology has meant more events can be recorded
- The global population is now 8 billion, compared to less than 3 billion in 1960. This means more people are living in areas which are vulnerable to the affects of natural disasters
- Urbanisation means more impermble surfaces (floods) and more buildings which are vulnerable to ground shaking
Why is the Phillipines considered a multiple hazard zone?
- Sits on major convergant plate boundary (pacific and Eurasia) so is vulnerable to tectonic hazards (mount Pinatubo)
- It sits upon South East Asias Typhoon belt, is is frequently struck with Hydro-meterological hazards (affected by 15 typhoons a year)
In 2015, 8 of the 10 most vulnerable cities were all in the Philippines
What is an example of hydrometerological hazards and techtonic hazards interacting?
During the 1991 eruption of Mount Pinatubo in the Philippines the area was struck by Typhoon Yunga. Heavy rainfall from the typhoon mobilised volcanic ash into destructive lahars
Whats the difference between prediction and forecasting?
Prediction means knowing when are where a natural hazard will strike on a spatial and temporal scale that can be acted on meaningfully in terms of evacuation.
Forecasting is much less precise than prediction, and provides a percentage change of a hazard occurring
What predicition and forecasting can be done for earthquakes?
Cannot be predicted temporally - only areas at high risk can be identified, plus areas that are likely to suffer severe ground shaking and liquefaction; this can be used for land-use zoning purposes -
‘Seismic gaps’, i.e. areas that have not experienced an earthquake for some time and are ‘overdue’ can point to areas of high risk. The speed of onset earthquakes have means little can be done to reduce the vulnerability to earthquakes immediately before, however in the long run local and national governments can use the spatial information to educate and invest in infrastrcutre
What prediciton and forecasting can be done for volcanoes?
- Can accurately be predicted
- Tiltmeters and strain meters record volcanoes ‘bulging’ as magma rises.
- Gas spectrometers analyse gas emissions
- 1991, increased levels of sulphur dioxide emitted from Mount Pinatubo was measured, and thus gave enough evidence to justify an evacuation of 20,000 people from an area of 30 km around the volcano - thus, despite being a massive eruption, a 6 on the VEI scale, only 847 died. This shows how critical prediction is in terms of modifying vulnerability, as it gives the credibility organisers need to undergo significant preparation and avoid hazard fatigue, which would increase dissent and thus increase morality.
What prediciton and forecasting can be done for tsunami?
While the earthquake can’t be predicted, scientists can detect an earthquake and use this to predict the tsunami. Prediction of tsunami and eruptions depends upon technology, which has to be: in place, operational and linked to warming dissemination and evacuation systems
Tsunami monitoring equipment was not present in the Indian Ocean in 2004 so there wasn’t a way of warning people on distant coasts. Thus, it is tied to levels of development and preparedness
The importance of different stages in the hazard management cycle (response, recovery, mitigation, preparedness).
- Response - the immediate response to a disaster to help those affected by it - this reduces the human cost of a disaster
- Recovery - Helping people recover from a hazard and return to normal life. Both in the short term - shelters, restoring of electricity and water, and in the long term - financial assistence and home rebuilding
- Mitigation - Reducing the vulnerability, and reduce the potential for the loss of life and economic loss. E.g land use zoning and building regulation
- Preparedness - ensuring communities have the capacity to cope with the next hazard, through education and the investment in services.
The effectiveness will depend on levels of development and the competence of governance
Park model
What are the 3 stratergies to modify the event? Pros, cons and example
- Land use zoning - limit how communities can use land - reduce the people and infrastructure in vulnerable areas, reducing loss. Eg mount Taranaki in New Zealand. However, this can be expensive and hinder development by reducing economic activity. In addition, it requires strong government regulation to enforce
- Diverting lava flows - divert lava flows away from communities. Has worked occasionally - such as Mount Etna in Italy. However, on the whole they have been fairly ineffective - the exact path of lava flows is difficult to predict, and the gradient must be suitable. If lava is ellusive it may run too quickly to react.
- Hazard resistent design - Collapsing buildings are the main cause of death and economic damage for earthquakes, so reduces the human and economic costs of the event while also aiding the response. Taipei 101 in Thailand has a steel pendulem within it to counteract ground shaking. Can be used in LICs as well - in Pakistan, roofs made out of straw reduce the risk of dangerous collapse. However, a weak government may not implement this due to corruption
What are the 3 stratergies to modify the vulnerability? Pros, cons and example
- Monotoring and prediciton - volcanoes and tsunamis, being able to predict an event temporally means warnings can be sent out to communites at risk and, if given enough time, vulnerable people can be evacuated. Mount Pinatubo 1991 - gas spectrometers detected sulphur dioxide emmisions which allowed 20,000 people to be evacuated. However, cannot be used for earthquakes and requires infrastructure to be in place before hand
- Education - reduces the vulnerability of a population, as they are aware of what steps to take in an emergency. Japan has earthquake drills in school 4 times a year. However, it does not prevent property damage and economic losses. It can be relatiely low cost though
- community preparedness- increasing capacity to cope using own resources. EG the distribution of earthquake kits to schools and househoulds. Most effective when formalised. People may make a list of vulnerable people to aid.
What are the 3 stratergies to modify loss? Pros cons and examples
- Aid - both short term (search and resue, food and water) and long term (financial assistence). Often coordinated by national governments and NGOS. It is especially useful when the government does not have the capacity to cope using its own resources. Haiti 2010 - The EU €330 million for emergency and long-term aid. However, may make the country reliant on outside factors
- Insurance - helps to reduce the private economic impacts on individual people. However, it is not available in the developing world and these private companies are driven by the profit motive. As of March 2024, the 2011 earthquake off the Pacific coast of Tohoku has caused the highest amount of reinsurance claims paid in Japan, with the total sum amounting to around 1.29 trillion Japanese yen
- Local community efforts - they will be the first to respond, and will have the most indepth knowledge of the local community. Especially helpful in geographhically isolated communities where aid may take a long time to arrive (Nepal 2015 rescue groups). However, community may lack resources.
