Tectonic hazards: earthquakes and tsunamis Chapter 1 - Keith Smith 2013
Hazard in the Environment
Introduction
- The Earth's population is larger, healthier, and wealthier than ever before.
- There is an unprecedented awareness of risks, including:
- 'Natural' hazards (earthquakes, floods).
- Hazards originating in the built environment (industrial accidents, technology failures).
- Emerging dangers (climate change, sea-level rise, biodiversity loss).
- A paradox exists between material progress and feelings of insecurity because economic development and environmental hazards are rooted in the same processes of global change.
- Trends:
- As the world population grows, more people are exposed to hazards.
- As the population becomes more prosperous, more wealth is placed at risk.
- As agriculture intensifies and urbanization spreads, more complex infrastructure is exposed to damaging events.
- Rising levels of human consumption put heavy burdens on natural assets.
- Uncertainties arise about environmental quality, resource availability, and sustainability.
- People in less developed countries experience insecure lives due to poverty, weak governance, and degraded resources, making them vulnerable to hazards.
- Modern communications (news, social media) allow rapid dissemination of information about disasters.
- It is hard to contextualize individual disasters and assess risk amidst the constant information flow.
- Questions to consider:
- Is the world becoming more dangerous?
- What are the causes of increasing dangers?
- What are the main environmental threats?
- What is a disaster?
- Why are advanced nations still vulnerable?
- Why do disasters kill more people in poor countries?
- What effects do disasters have on economic development?
- Why do some disasters create greater losses than their physical scale suggests?
- Is climate change an environmental hazard?
- What are the best ways to reduce the impact of hazards and disasters?
- It is impossible to live in a totally risk-free environment.
- We face risks regularly (road accidents, theft, pollution).
- Some risks are adopted through lifestyle choices (smoking, overeating, dangerous sports).
- Self-imposed risks can lead to premature deaths but are dispersed throughout the population.
- Disasters disrupt whole communities due to concentrated deaths and damages.
- Environmental hazards lie at the interface between natural events and human use systems, interacting with global change and sustainable development and influenced by societal responses.
What are Environmental Hazards?
This text focuses on extreme, rapid-onset events that threaten human life and property through physical or chemical trauma on a large scale.
Losses follow the sudden release of energy or materials in concentrations exceeding normal levels.
Environmental hazard is limited to events originating in the natural and built environments that cause human deaths, economic damage, and other losses above predefined thresholds.
Loss thresholds define a disaster.
Hazards and disasters are linked to global environmental change and sustainable development.
Two main types of environmental hazards:
Natural hazards
Defined by the UN/ISDR (2009) as any natural process or phenomenon that may cause loss of life, injury, property damage, social and economic disruption, or environmental damage.
Major categories include:
- Geologic: earthquakes, volcanic eruptions, landslides, avalanches
- Atmospheric: tropical cyclones, tornadoes, hail, ice, and snow
- Hydrologic: river floods, coastal floods, drought
- Biologic: epidemic diseases, wildfires
The description is well-rooted in the literature but fails to provide a scale of loss.
Most suitable for hazards like earthquakes and volcanic eruptions, where damaging processes are truly 'natural' in origin because they remain unaffected by human actions.
The Earth’s surface and atmosphere are increasingly subject to anthropogenic change.
Although all 'natural hazards' are triggered by physical forces, certain events and their outcomes may be influenced by human actions.
Some types of natural hazards become quasi-natural hazards.
- Example: The impact of a river flood may be increased by deforestation or decreased by a control dam.
Where an increase in the frequency or severity of hazardous events can be attributed to degraded land, the term socio-natural hazard is used.
Natural-technological ('na-tech') hazards:
Arise when extreme natural processes lead to the failure of industrial structures.
The main threat often comes from pollution due to accidental releases of dangerous substances.
Examples:
- Radioactive pollution from damage to the Fukushima nuclear power plant (Japan) in March 2011 by the Tōhoku earthquake and tsunami
- Italy losing electricity in 2003 due to storm-force winds in Switzerland damaging transmission lines importing power
- Floods and earthquakes destroying river dams
- 1963 landslide displacing water over the Vaiont dam in Italy
Technological hazards
Defined by the UN as hazards originating from technological or industrial conditions, including accidents, dangerous procedures, infrastructure failures, or specific human activities, that may cause loss of life, injury, property damage, or environmental damage.
Most threats arise from human errors which expose flaws in design or functioning.
Once again, the definition provides no numerical scale of loss.
Categories include:
- Transport accidents (air, train, ship)
- Industrial failures (explosions, fires, toxic releases)
- Unsafe public buildings (structural collapse, fire)
- Hazardous materials (storage, transport, misuse)
The causes of environmental hazards are reasonably well understood, and databases illustrate their spatial and temporal patterns.
Localized threats are often linked to wider-scale processes (e.g., landslides from tectonic mechanisms).
Many physical processes are driven by forces that operate on hemispheric or planetary scales.
Some events, like asteroid collisions, could create global catastrophes.
Hazardous processes are influenced by global environmental change (GEC), including both natural climate variations and human-induced modifications.
Global interactions and environmental changes amplify the disaster potential of existing threats.
A better understanding of the coupled human–environment system (CHES) is needed.
Hazards and disasters are complex issues nested within global change and sustainability.
They can no longer be viewed as one-off events regulated by local responses alone.
Global warming drives sea-level rise, increasing coastal flood risks.
Adverse effects of natural hazards on economic development and food/water security are less self-evident.
There is a lack of historical experience and scientific record to enable understanding, and some issues remain controversial.
Most environmental hazards can be placed on a scale of causation from natural forces to human influence.
As human causation grows, disaster impacts become less concentrated, and the public is more accepting of any loss.
Voluntary lifestyle hazards and hazards of mass violence are excluded.
Societal characteristics influence hazard impacts.
Some epidemics are accepted due to their link to environmental conditions.
Poverty, ill-health, and environmental degradation amplify human vulnerability.
Chief features of environmental hazards:
- Clear origin of the event with known threats
- Short warning time
- Direct losses suffered shortly after the event
- Largely involuntary human exposure
- Justifies an emergency response
- Uncertainty about loss makes risk assessment difficult
- Represent extremes of statistical distributions
The environment is neutral; human use identifies resources and hazards.
Human sensitivity is determined by exposure and vulnerability, which change through space and time.
Industrialized nations reduce exposure and vulnerability through environmental security investments.
Poor countries with high exposures struggle to fund protection, leading to disproportionately high losses.
All systems exhibit variability, but activities are geared to 'average' conditions.
An element becomes a hazard when it fluctuates beyond a critical threshold.
Hazard magnitude is determined by the peak deviation, and hazard duration by the time the threshold is exceeded.
The potential time-scale of hazard duration ranges over at least seven orders of magnitude.
The ever-changing balance between environmental hazards and resources can be illustrated in many ways, e.g. Mediterranean tourism.
Human populations are especially at risk on the margins of hazard tolerance, where small physical changes create large socio-economic impacts (rainfall variability on agriculture).
Frequent low-level variability around a critical threshold may have as much significance as rare extreme events.
Sudden change is an integral part of all natural systems, but the very rarest events may not be recognized as threats.
Hazards are a human interpretation of extreme or rare events observed within individuals' lifetimes.
Tohoku 2011: a major na-tech disaster
The Great Tōhoku earthquake in Japan is a classic example of a na-tech disaster.
The 'knock-on' series of events triggered by an earthquake, quickly followed by tsunami waves, caused extensive damage to a nuclear power facility and released significant amounts of radioactive material into the environment.
Step One
- On 11 March 2011, the island of Honshu, north-east Japan was struck by an earthquake of magnitude . At the time, this was the largest instrumentally recorded earthquake ever to hit Japan.
- The offshore epicentre was roughly 70 km east of the Oshika Peninsula of Tōhoku, on the Sanriku coast, with a hypocentre 30 km below sea level.
- The earthquake resulted from thrust faulting at the plate boundary between the Pacific and Indo-Australian–Fiji plates (see Figure 6.1).
- At this point, the Pacific Plate is moving to the west at a rate of . The boundary is a subduction zone where the Pacific Plate descends beneath Japan at the Japan Trench (USGS, 2011).
- Since 1973, nine events of magnitude or greater have occurred here, although no earthquake during the twentieth century attained a magnitude of or more.
Step Two
- The earthquake triggered tsunami waves up to almost 40 m high in places that struck the coast several minutes later. Some waves travelled inland for up to 10 km.
- The Sanriku coast has many deep coastal bays which constrain and amplify the height of approaching tsunami waves, and similar disasters in historic times occurred in 1611, 1854, 1896 and 1933.
- The coast is protected by extensive sea walls, some 12 m high, but most were easily over-topped.
- The combined death toll from the earthquake and tsunami was at least 20,000, with 14,000 homes destroyed and 100,000 properties damaged.
- The Japanese Red Cross sent 230 response teams and over 2,000 evacuation centres were set up in north-east Japan.
- This was the most expensive disaster in Japanese history. Total economic damages were estimated at a record US$366 billion, with insured property losses of US$20–30 billion. About US$4,000 billion was wiped off the Nikkei 225 stock market index, which initially fell by over 6 per cent.
Step Three
- The tsunami flooded the coastal Fukushima I nuclear power station. The plant, operated by the Tokyo Electric Power Company, was 40 years old and produced 4,696 MW of electricity.
- It comprised six boiling water reactors, designed to withstand a earthquake and 5.7 m tsunami wave.
- The earthquake activated an automatic shut-down system and emergency generators started to run the sea-water pumps used for cooling the reactors. But the entire plant, including the diesel generator building, was struck by 14 m high tsunami waves.
- As a result of generator failure, four reactors began to overheat and three ultimately suffered meltdown.
- Explosions caused by a build- up of hydrogen gas in the outer containment buildings released radioactive material and levels of 400 millisieverts (mSv) were recorded at No 4 reactor. This compares with the 350 mSv criterion adopted for evacuation at Chernobyl.
- A 20 km exclusion zone was declared around the Fukushima I nuclear power station, with a 10 km zone for the Fukushima II power plant. In total, around 80,000 residents were evacuated.
- Initially the incident was rated 5 on the 7-point International Nuclear Event Scale but later it was reassessed at the highest level.
- This was the first Category 7 nuclear accident since the Chernobyl disaster of 1986, indicating risks to human health and environmental contamination from leakage of cooling water and contamination of coastal waters.
- Following the emergency phase, the main priority was to cool the reactors with recirculated water to safe temperatures below 100°C.
- In the initial response, helicopters were used to drop limited amounts of sea-water and, in the absence of relief generators and with the loss of electrical power on site, radioactive steam had to be released manually.
- Eventually, large quantities of sea-water were pumped ashore and by December 2011 the plant was declared to be in ‘cold shutdown’.
- However, water cooling will be necessary for several years while the radioactive fuel in the reactors slowly decays.
- The removal of fuel from the three most-damaged reactors is unlikely to occur within the next 10 years. Full decommissioning of the plant would include the decontamination of an area extending to , the disposal of an estimated 90,000 tonnes of contaminated sea-water and the removal of millions of cubic metres of topsoil. This process could cost up to US$50 billion and take 40 years to accomplish.
Hazard, Risk and Disaster
Environmental hazards create threats:
- To people: death, injury, disease, mental stress
- To goods: property damage, economic loss
- To environment: loss of flora and fauna, pollution, loss of amenity
Threats to human life are normally given the highest priority, followed by losses to material assets.
Most disasters are characterized by a minimum level of human mortality.
Fatalities and economic damages can be assessed directly and are the basis for scaling hazard impacts in disaster.
The environment attracts less attention in disaster assessment.
It is difficult to explicitly link human mortality to environmental pollution or declines in ecosystem quality.
It is also more difficult to calculate the value of environmental resources on conventional financial scales.
Hazard and disaster can be ranked according to impact criteria, and the probability of a hazardous event can be placed on a scale from zero to certainty (0 to 1).
The relationship between a hazard and its probability can then be used to determine the overall level of risk.
Risk is sometimes taken as synonymous with hazard, but risk has the additional implication of the statistical chance of experiencing a particular hazard.
Hazard is best viewed as a naturally occurring or human-induced process or event with the potential to create loss, i.e., a general source of future danger.
- Hazard (the cause): a potential threat to humans and their welfare arising from a dangerous phenomenon or substance that may cause loss of life, injury, property damage, and other community losses or damage.
Risk is the actual exposure of something of human value to a hazard and is often measured as the product of probability and loss.
- Risk (the likely consequence): the combination of the probability of a hazardous event and its negative consequences.
The difference between hazard and risk:
- Two people crossing an ocean, one in a large ship and the other in a rowing boat (Okrent, 1980).
- The hazard (deep water and large waves) is the same but the risk (probability of capsize and drowning) is much greater for the person in the rowing boat.
- The type of danger posed by earthquakes may be similar throughout the world, people in poorer countries are often more vulnerable and at greater risk than those in richer countries.
When large numbers of people are killed, injured, or otherwise adversely affected, the event is termed a disaster.
- Disaster (the actual consequence): a serious disruption of the functioning of a community or a society involving widespread human, material, economic, or environmental losses or impacts which exceed the ability of the affected community or society to cope using its own resources. UN/ISDR (2009)
Environmental hazards stem from natural events, but disasters are social phenomena that occur when a community suffers exceptional levels of disruption and loss.
Although a hazardous event can occur in an uninhabited region, risk and disaster can exist only in areas where people and their possessions are located.
The sequence of events leading to a disaster:
- Extreme Event → Risk → Disaster (if no protection)
A disastrous train of events can occur if humans place unrealistic demands on the environment or select a technology that eventually fails, with harmful consequences (Hohenemser et al., 1983).
A disaster sequence for drought:
- Causal Stages (top line): Precipitation Deficiency → Soil Moisture Deficiency → Reduced River Flow → Water Shortage → Crop Damage → Food Shortage
- Possible Control Stages (below): Cloud Seeding → Irrigation → Demand Management → Rationing → Food Imports
- If control measures fail: Famine-related Deaths
Direct cause-and-effect linkages rarely operate, and complex emergencies develop.
When fires and explosions occurred in the 1906 San Francisco earthquake: the primary hazard was strong ground shaking, the secondary hazard was soil liquefaction, and the tertiary hazard was fire and explosion.
In general, the profile of disaster loss portrayed in the media is not matched by the actual incidence of deaths or damages.
Headline media reports arise infrequently.
In the United States, natural hazards killed about 1,250 people per year and injured a further 5,000, only one-quarter of the fatalities and half the injuries resulted from major disasters.
Most deaths stemmed from small, frequent events (lightning strikes, car crashes in fog, and local landslides).
In Italy, the death rate from road accidents is over 200 times that from landslides but still remains low for the population as a whole (Guzzetti, 2000).
A mere 0.01 per cent of the US population has died from natural disasters (Fritzsche, 1992).
Natural hazards in the USA regularly damage public facilities, the losses are only 0.5 per cent of the capital value of the nation’s infrastructure.
Average disaster relief costs are less than 1 per cent of the total federal budget (Burby et al., 1991).
Deaths and injuries from disasters are often reported as safely issues, especially in the developed countries (Sagan, 1984).
These accidental deaths are perceived differently from chronic human illnesses.
In more developed countries (MDCs), average mortality from all causes is strongly dependent on age.
The death rate tends to be high during the first few years of life but soon drops sharply. It then rises steadily until, at age 70 and beyond, it exceeds infant mortality. This pattern reflects the importance of lifestyle factors and degenerative diseases in the western world, where some 90 per cent of all deaths are due to heart disease, cancers and respiratory ailments.
Tobacco consumption is a major factor; worldwide about 3 million people die prematurely each year through smoking.
Accidental deaths from all causes rarely constitute more than 3 per cent of mortality in the MDCs.
In less developed countries, the per capita risk of a disaster-related death has been estimated to be between 4 and 12 times greater than in the industrialized countries.
The one-third of the world’s population living in low-income countries suffers almost two-thirds of all disaster-related deaths (Strömberg, 2007).
Disaster-related deaths in high- and low-income countries 1980–2004: Exposed population suffers disproportionately more deaths in low-income vs high-income countries.
Environmental hazards are not the only cause, given the greater presence of risks like disease epidemics and armed conflicts in the LDCs.
Cumulative losses from ‘headline disasters’ are relatively low in relation to other causes of premature death and damage, especially in the MDCs.
Disasters and accidental losses are newsworthy because the impacts are highly concentrated in space and time and often provide striking photographs and television footage.
Earlier Perspectives
Our understanding of hazards and disasters has changed through history.
A concern for earthquake and famine began in the earliest times (Covello and Mumpower, 1985).
Great catastrophes were seen then as ‘acts of God’ rather than as a consequence of human use of hazard-prone land.
This view encouraged acceptance of disasters as external, inevitable events.
Communities learned to avoid the most dangerous sites.
Organized attempts were made to limit the damaging effects of natural hazards, an approach that led to the development of the four hazard paradigms:
Engineering Paradigm
- Originated with the first river dams constructed in the Middle East over 4,000 years ago.
- Attempts to defend buildings against earthquakes date back at least 2,000 years.
- This approach is based on ‘hardening’ built structures to withstand most hazard stresses and evacuating people from harm by emergency action.
- The growth of the earth sciences and civil engineering practices over the following centuries led to increasingly effective structural responses designed to control the damaging effects of certain physical processes.
- By the end of the nineteenth century new measures, like weather forecasting and severe storm warnings, could also be used.
- It is largely undertaken with the aid of science-based government agencies and remains a necessary and important strategy today.
Behavioral Paradigm
- Originated with an American geographer, Gilbert White (1936, 1945).
- Natural hazards are linked to societal decisions to settle and develop hazard-prone land, often for economic motives.
- White was critical of the undue reliance placed on engineered structures to control floods and other hazards in the USA and introduced the social perspective of human ecology.
- This interpretation stems from earlier work in the 1920s, notably by Harlan H. Barrows, who applied concepts from ecology to the functioning of human communities. The basic idea was that the interactive nature of human–environment relations defines the well-being of both.
- Human ecology links the physical and social sciences to provide a more balanced approach to resolving the conflicts that arise between human needs and the sustainability of the environment.
- Gilbert White was the first person to question whether truly ‘natural’ hazards exist at all.
- He proposed that, instead of attempting to control nature’s extreme events, people should adapt their behaviour to the uncertainties raised by the magnitude and frequency of physical processes.
- Engineers continued to build to standards designed to withstand natural forces and scientists introduced other technocratic advances, for example in hazard monitoring and warning schemes.
- Simultaneously, social scientists explored how disasters might be reduced through human adjustments, such as insurance and better land planning.
- This combined hazards-based viewpoint became widely accepted and was summarized in several books from the North American research school (White, 1974; Burton, Kates and White, 1978, rev. 1993).
Development Paradigm
- Emerged during the 1970s as a more theoretical and radical alternative.
- It drew on experience in the less industrialized parts of the world, where natural disasters create more severe impacts, including large losses of life.
- Answers were sought in the longer-term, root causes of disasters and the research focus shifted from hazards to a disasters-based viewpoint and from the MDCs to the LDCs.
- The link between under-development and disasters was scrutinized, and it was concluded that economic dependency increased both the frequency and the impact of natural hazards.
- Human vulnerability became an important concept for understanding disaster impacts (Blaikie et al., 1994; Wisner et al., 2004).
The twentieth-century paradigm debate:
Past divisions arose between the technology-based behavioural paradigm, adopted by government bodies, and the theoretical development paradigm, favoured by social scientists.
The behavioural paradigm:
Engineering responses to environmental hazards go back a long way but modern approaches began in the USA.
Following the 1936 Flood Control Act, the US Army Corps of Engineers constructed major flood-control works (dams and levees) throughout the country.
This strategy appeared rational during the 1930s and 1940s, due to growing confidence in the relevant scientific fields (meteorology, hydrology), political demands for greater development of natural resources and the availability of capital for public works.
Gilbert White was at first a lone voice in arguing that flood control works should be integrated with non-structural methods, like land use planning, to produce more comprehensive floodplain management. His view recognized the role played by human behaviour in creating hazards.
Urban development of flood-prone land was attributed to ‘behavioural’ or cultural faults, including a mis- perception — by developers and home-owners alike — of the risk/reward balance that exists when hazardous land is occupied for economic gain.
Within the developing countries, other forms of behaviour, such as deforestation or the over-grazing of land, were considered irrational and thought to contribute to disaster.
The universal purpose of disaster reduction was to prevent these temporary disruptions to ‘normal’ life.
Although White’s ideas gained some attention, ‘technical fix’ solutions dominated. It was believed that, in the fullness of time, the transfer of technology from the developed to the developing world, as part of an overall modernization process, would solve its problems too.
Many centralized organizations were created because only government-backed bodies had the financial resources and expertise needed to apply science and engineering on the required scale. The United Nations, in particular, sprouted a number of agencies responsible for international disaster mitigation at this time.
According to Hewitt (1983), the behavioural paradigm had three thrusts:
- Despite some acknowledgement of the role of human behaviour in the occupation of hazard- prone land, the prime aim was to contain nature through engineering works, such as flood embankments and earthquake-proofed buildings, allied with land use controls.
- Other measures included field monitoring and the scientific explanation and statistical assessment of geophysical processes. Modelling and prediction of damaging events followed the introduction of advanced technical tools, e.g. remote sensing and telemetry.
- Priority was given to strengthening bureaucracy for disaster planning and emergency responses, mostly operated by the armed forces. The notion that only a military-style organization could function in a disaster area was attractive to governments because it emphasized the authority of the state when re-imposing order.
This paradigm has a cultural emphasis but also contains practical methods for loss reduction.
It remains important but has been described as an essentially Western interpretation of disaster.
Critics see this approach as materialistic, reflecting undue faith in technology and capitalism leading to ‘quick fix’ remedies.
It has also been faulted for overemphasizing the role of individual choice, against the power of financial bodies and other institutions, in hazard-related decisions; for neglecting environmental quality, for example in the construction of control schemes and the drainage of wetlands as a flood reduction measure, and for down-playing human vulnerability in disasters.
The development paradigm:
This philosophy emerged due to slow progress in reducing disaster losses in poorer countries.
It originated with social scientists who believed that disasters in the Third World arise principally from the workings of the global economy and the marginalization of disadvantaged people.
Extreme natural events were seen as ‘triggers’ of deeply rooted and long-standing problems, especially poverty.
This more radical interpretation of disaster proposes fundamental change in economic, social and political systems.
Contrary to the behavioural paradigm, it dwells on the long-term common features of disaster and stresses the limits to individual actions imposed by powerful financial and political interests.
The development paradigm was ably summarized in the work of Wisner et al. (2004), who envisage disasters as the outcome of a direct clash between the socio-economic processes that create human vulnerability and the natural processes that create geophysical hazards.
There are several key points:
- Disasters are caused largely by human exploitation rather than by natural or technological processes.
- Macro-scale root causes of vulnerability lie in the economic and political systems that exercise power and influence, both nationally and globally, and result in marginalizing poor people.
- On-going pressures, such as chronic malnutrition, disease and armed conflict, channel the most vulnerable people into unsafe environments, such as flimsy housing, steep slopes or flood-prone areas, either as a rural proletariat (dispossessed of land) or as an urban proletariat (forced into shanty towns).
- Effective local responses to hazards are limited by a lack of resources at all levels.
- ‘Normality’ in the Western sense is an illusion. Frequent disaster strikes are characteristic, rather than unusual, and reinforce socio-economic inequalities. Disaster reduction in poor countries depends on fundamental changes and a re-distribution of wealth and power. Modernization — relying on imported technology and ‘quick fix’ measures — is inappropriate. Instead, self-help using traditional knowledge and locally negotiated responses is seen as a better way forward.
In summary, the development view is based on the theory that disasters spring from under- development arising from political dependency and unequal trading arrangements between rich and poor nations. The poorest sections of society are forced to over-use the land and other resources, so that this behaviour cannot be regarded as ‘irrational’. Specifically, rural over-population, landlessness and migration to unplanned, hazard-prone cities are the inevitable outcomes of capitalism, which is the root cause of environmental disaster.
In the immediate future, the political economy of the world is unlikely to change sufficiently in ways favoured by the development lobby. However, the paradigm has been helpful in refining some key concepts, such as the importance of poverty and vulnerability amongst disadvantaged people everywhere.
Geophysical processes are not the sole contributor to disaster impact, any more than humanitarian aid is a permanent solution to deep-seated socio-economic problems in poor countries. A better understanding of socio-economic conditions is clearly needed and human vulnerability analysis and mapping is now routinely undertaken alongside geophysical risk assessments when planning for disaster reduction.
Physical scientists, including civil engineers and meteorologists, were associated with the agent-specific, hazard-based behavioural paradigm using technical solutions plus some adaptation measures derived from human ecology.
Social scientists, such as sociologists and anthropologists, drew on the development paradigm and adopted a cross-hazard, disaster-based view that stressed failings within political and social systems, together with the need to improve the efficiency of human responses to all types of mass emergency (Quarantelli, 1998).
The behavioural and development paradigms enriched the study of hazard and disaster, each approach has crucial shortcomings.
A broader, more integrated view that sees disaster as the outcome of complicated interactions between many variables — physical, technological, social and institutional.
Dynes (2004) called for a vision that broadens beyond the Western focus on the rapid-onset hazards threatening largely urban communities to embrace modern-day threats that range from the multi-layered emergencies afflicting the rural poor in the LDCs to the disasters that still occur in the richest mega-cities of the MDCs.
Current Views: The Complexity Paradigm
The need for a new paradigm can be illustrated by a tale of two hurricanes (Petley, 2009).
Hurricane ‘Mitch’ (1998) and Hurricane ‘Felix’ (2007).
Hurricane ‘Mitch’:
- On 28 October 1998, hurricane ‘Mitch’ made landfall on the coast of Honduras as a Category 5 storm — the strongest category of tropical cyclone.
- Over the next three days it crossed Honduras, Nicaragua and Guatemala, creating much destruction in Central America
- By 2 November at least 11,000 people had been killed and a similar number were missing.
- Most deaths resulted from mudslides and flash floods which caused economic damage, estimated at over US $5 billion, in areas that were already poor.
Hurricane ‘Felix’:
- On 2 September 2007, hurricane ‘Felix’, another Category 5 storm, made landfall on the border between Honduras and Nicaragua at almost the same location as ‘Mitch’.
- It also tracked across Honduras, Nicaragua and Guatemala, bringing strong winds and intense rainfall.
- But this time, the losses were far fewer. The estimated number of fatalities was 135, less than one per cent of the deaths in hurricane ‘Mitch’, whilst the economic damage was a fraction of that previously recorded.
The two storms had a similar size and intensity, and followed similar tracks, but had different impacts. Why should this be so?
A behaviourally based answer would stress the forces of nature.
Perhaps the intensity and duration of rainfall was much greater for hurricane ‘Mitch’ than for ‘Felix’.
- Hurricanes are graded according to maximum wind speeds rather than rainfall, the characteristics of which were responsible for most of the losses in ‘Mitch’.
A development-based response would stress the vulnerability of the local population.
- After hurricane ‘Mitch’, new disaster reduction measures were implemented — relocation of people away from the most dangerous areas, plus improved emergency planning — that would have reduced the impact of ‘Felix’ to some extent.
Hazard researchers and disaster managers have now merged the natural and social sciences in a more even-handed way.
The complexity paradigm looks beyond local, short-term loss reduction in order to mesh disaster reduction with a realistic development agenda that secures a more sustainable future.
A new hazard paradigm does not imply a complete rejection of previous ideas but represents a shift in emphasis.
Most successful paradigms capture best practice from the past and absorb that experience into a fresh approach.
The focus here has shifted from preparedness and emergency response towards mitigation that includes long- term recovery and improvement, as well as societal issues like vulnerability and resilience (Wenger, 2006).
Previous strategies remain relevant.
It is difficult to envisage a world in which well-designed engineering works, good land planning and effective humanitarian aid play no part in disaster reduction.
The complexity approach embeds hazards and disasters within global issues like climate change and sustainability (see Chapter 3).
Humans are not simply the victims of hazards; they themselves contribute to hazardous processes and to disaster outcomes.
Human actions over-exploit and degrade natural resources through processes like deforestation and global warming that, in turn, amplify the risk from natural hazards like river floods and sea-level rise.
The exact relationships between ‘traditional disasters’ and ‘complex emergencies’ — and between these disasters and the forces of global environmental change — are presently unclear.
This is because we are only just starting to understand the extent of human domination of the Earth’s ecosystems and the extent to which this influences the vulnerability of societies to extreme events (