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2Chapter

Risk awareness and assessment2.1 Understanding the nature of risk2.2 Emerging trends in hazards,

vulnerability patterns and the impactof disasters

2.3 Risk Assessment

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2.1 Understanding the nature of risk

Disaster risk is part of every day life. Awareness of risk is therefore a necessary condition to engage in disasterrisk reduction. A focus on risk management, rather than on disaster events alone, reflects a proactive attitudefor dealing with potential threats to social and material assets, before they are lost.

The analysis and lessons learned from prior experiences of disasters help to define profiles of risk related topeople, activities and places that share attributes, in the face of particular potential sources of loss or damage.

Understanding risk relates to the ability to define what could happen in the future, given a range of possiblealternatives to choose from. Assessing risks based on vulnerability and hazard analysis is a required step for theadoption of adequate and successful disaster reduction policies and measures.

This chapter will discuss:

• the nature of risk, with emphasis on the linkages between hazards and vulnerability;• emerging trends in hazard and vulnerability patterns and the impact of disasters; and• risk analysis and assessments with examples of the application of these methodologies.

Levels of risk awareness depend largely onthe quantity and quality of availableinformation and on the difference inpeople’s perceptions of risk. People aremore vulnerable when they are not awareof the hazards that pose a threat to theirlives and property. Risk awareness variesamong individuals, communities andgovernments, according to their particularperceptions. These can be influenced bythe knowledge of hazards andvulnerabilities, as well as by the availabilityof accurate and timely information aboutthem.

Risk notation

Risk = Hazard x Vulnerability

Two elements are essential in theformulation of risk: a potential damagingevent, phenomenon or human activity –hazard; and the degree of susceptibility ofthe elements exposed to that source –vulnerability.

The negative impact – the disaster – willdepend on the characteristics, probabilityand intensity of the hazard, as well as thesusceptibility of the exposed elementsbased on physical, social, economic andenvironmental conditions.

The recognition of vulnerability as a keyelement in the risk notation has also beenaccompanied by a growing interest inlinking the positive capacities of people tocope with the impact of hazards. Itconveys a sense of the potential forcapabilities to reduce the extent of hazardsand the degree of vulnerability.

Social dimensions are intimately linked tothe decision-making process to deal withdisaster risk, as they embrace a range of riskperceptions and their underlying causes.

A closer look at the nature of hazards andthe notions of vulnerability and capacitiesallows for a more comprehensiveunderstanding of the challenges posed bydisaster risk reduction.

RRiisskk The probability of

harmful consequences, orexpected losses (deaths,

injuries, property,livelihoods, economicactivity disrupted or

environment damaged)resulting from interactions

between natural orhuman-induced hazards

and vulnerable conditions.

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Understanding the nature of hazards

Understanding the nature of natural hazardsinvolves a consideration of almost every physicalphenomenon on the planet. The slow movementsin the earth’s mantle – the convection cells thatdrive the movement of continents and themanufacture of ocean floors – are the starting andalso the sticking point. They lift mountains andshape landscapes. They also build volcanoes andtrigger potentially catastrophic earthquakes.

Like those other invisible movements that takeplace on a vast scale through the atmosphericmedium – the carbon cycle and the water cycleand the nitrogen cycle – volcanoes andearthquakes, along with technologicaladvancements, provide the bedrock of strongnations, rich industries and great cities. They do,of course, have the potential to destroy them.

While most natural hazards may be inevitable,disasters are not. By seeking to understand and toanticipate future hazards by study of the past andmonitoring of present situations, a community orpublic authority can minimize the risk of adisaster.

It is a measure of people’s wisdom and a society’svalues if a community is able to learn from theexperiences of others, rather than to suffer its own.There is a wealth of knowledge about the natureand consequences of different hazards, expectedfrequency, magnitude and potential geographicimpacts, but many fewer examples of lessonslearned from them.

Hazards are dynamic and with highly varyingpotential impacts. Due to changing environments,many countries and regional organizations requirea greater knowledge of hazard characteristics.

A wide range of geophysical, meteorological,hydrological, environmental, technological,biological and even socio-political hazards, aloneor in complex interaction, can threaten lives andsustainable development. Hazards have often beendivided into those deemed natural ortechnological, based on their origins. Asenvironmental degradation continues to worsen,the intensity, frequency and impacts of hazards arealso affected.

While natural hazards can be divided into threebroad categories – hydrometeorological, geologicaland biological – the variety, geographical coverageand types of impacts vary considerably.

Forest fires, for example, are recognized as anatural hazard but are often referred to asenvironmental hazards. In order to distinguishbetween different types of hazards someinstitutions have developed hazard catalogues.Figure 2.1 summarizes current hazard thinking.

The compound relationship between differenthazards means that cataloguing a hazard is oftencomplicated. At what stage does a landslide,typically recognized as a geological hazard,become a mudflow, which is often classified as ahydrological hazard?

In the same vein, primary hazards often give riseto collateral or secondary hazards. In many cases,these present greater threats to a community thando the primary hazards. Tropical cyclones andother storms can trigger other hazards, inparticular storm surges, flash floods andlandslides. Often the most serious impacts ofstorms come from the associated coastal and riverfloods. Similarly, damages related to earthquakesare often caused by landslides, fires, tsunamis orfloods.

Almost all communities – whether urban or rural– are vulnerable to hazards. Hydrometeorologicalhazards are most common and floods aloneaccount for two-thirds of people affected bynatural hazards. However, different regions willbe more prone to certain types of hazards thanothers.

Floods and windstorms are the hazards that mostfrequently lead to disasters in Asia, the Pacific,Europe and North America. Droughts andepidemics are reported more often in Africa, whilethe Pacific and Caribbean islands are mostvulnerable to the effects of tropical cyclones.

El Niño events, floods, volcanic eruptions andearthquakes have a greater impact on the Andeanand Central American countries. Even within aspecific region, such as the Pacific, the frequencyand intensity of specific hazards varies from onecountry to another.

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Figure 2.1W

orld map of natural hazards

Source: MunichRe, 1998

In the same way, different social groups are moreor less vulnerable to certain types of hazards.While disasters of all kinds affect the poor mostdirectly, women and men, people in different age

and ethnic groups, and those with different levelsof physical and cognitive ability, experiencedisasters differently.

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HAZARD A potentially damaging physical event, phenomenon or human activity, which may cause the loss of life or injury,

property damage, social and economic disruption or environmental degradation.

NATURAL HAZARDSNatural processes or phenomena occurring in the biosphere that may constitute a damaging event. Natural

hazards can be classified according to their geological, hydrometeorological or biological origins.

ORIGIN

Hydrometeorological hazardsNatural processes or phenomena of atmospheric,hydrological or oceanographic nature.

Geological hazardsNatural earth processes or phenomena that includeprocesses of endogenous origin or tectonic orexogenous origin, such as mass movements.

Biological hazardsProcesses of organic origin or those conveyed bybiological vectors, including exposure to pathogenicmicro-organisms, toxins and bioactive substances.

PHENOMENA / EXAMPLES

• Floods, debris and mudflows• Tropical cyclones, storm surges, wind, rain and

other severe storms, blizzards, lightning• Drought, desertification, wildland fires, temperature

extremes, sand or dust storms• Permafrost, snow avalanches

• Earthquakes, tsunamis • Volcanic activity and emissions• Mass movements, landslides, rockslides,

liquefaction, sub-marine slides• Surface collapse, geological fault activity

• Outbreaks of epidemic diseases, plant or animalcontagion and extensive infestations

TECHNOLOGICAL HAZARDSDanger associated with technological or industrial accidents, infrastructure failures or certain human activities whichmay cause the loss of life or injury, property damage, social and economic disruption or environmental degradation,

sometimes referred to as anthropogenic hazards. Examples include industrial pollution, nuclear release andradioactivity, toxic waste, dam failure, transport, industrial or technological accidents (explosions, fires, spills).

ENVIRONMENTAL DEGRADATIONProcesses induced by human behaviour and activities (sometimes combined with natural hazards) that damage

the natural resource base or adversely alter natural processes or ecosystems. Potential effects are varied and maycontribute to an increase in vulnerability and the frequency and intensity of natural hazards. Examples include landdegradation, deforestation, desertification, wildland fires, loss of biodiversity, land, water and air pollution, climate

change, sea level rise and ozone depletion.

Table 2.1Hazard classification

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Figure 2.2Distribution of natural disasters, by country and type of phenomenon 1975-2001

Source: EM-DAT: The OFDA/CRED International Disaster Database - www.em-dat.net - Université Catholique de Louvain - Brussels - Belgium, 2004

Figure 2.3Number of people killed (income class/disaster type), world summary 1973-2002

DroughtExtreme temperatureWildfireEarthquakeVolcano

FloodWave / SurgeLandslideWind strormEpidemic

0 200 000 400 000 600 000 800 000 1 000 000 1 200 000 1 400 000 1 600 000

Low income

Lower middleincome

Upper middleincome

High income

Source: EM-DAT: The OFDA/CRED International Disaster Database - www.em-dat.net - Université Catholique de Louvain - Brussels - Belgium, 2004, based on elaboration by ADRC

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Understanding the nature ofvulnerability and capacity

Risk is rooted in conditions of physical,social, economic and environmentalvulnerability that need to be assessed andmanaged on a continuing basis. Theprimary objective is to minimize exposureto hazards through the development ofindividual, institutional and societalcapacities that can withstand loss ordamage.

Over the past 30 years there has been asignificant and important development inthe understanding about people’ssusceptibility to hazards. The concept ofvulnerability was initially used byengineers in considering constructiondesigns related to levels of resistance tophysical forces exerted by ground motion,wind and water.

During the 1980s and 1990s, there was agrowing interest in the linkages betweendisasters and development. Originallyfocused on considering the impact ofdisaster on development, the scope ofinterest has since been expanded toaddress the impact of development on thetoll of disaster-related damage. Thisexpressed a new range of socio-economicand environmental concerns built aroundthe notion of vulnerability.

The role of community participation andpeople’s general coping capacities are alsorecognized as key elements in explainingdisaster risk. The creative link between thenegative conditions with which people live,and the often overlooked positiveattributes which they also possess,underline the importance of the socio-economic dimensions of risk.

However, it remains a challenge toencourage the identification of locallyavailable strengths and capacities that canreduce risk to hazards. The importance ofrevealing capacities hidden in non-disastertimes becomes a critical task for disasterrisk reduction. Capacities apply to alllevels of society and social organizations,

and encompass a broad range of physical,social, economic and ecologicalconsiderations.

Vulnerability is a reflection of the state ofthe individual and collective physical,social, economic and environmentalconditions at hand. These are shapedcontinually by attitudinal, behavioural,cultural, socio-economic and politicalinfluences on individuals, families,communities and countries.

Governed by human activity, vulnerabilitycannot be isolated from ongoingdevelopment efforts. It therefore plays acritical role in all the aspects of sustainabledevelopment.

Figure 2.4 illustrates the four broad areasin which different aspects of vulnerabilitycan be grouped, depicted by intersectingcircles to show that all spheres interactwith each other.

Physical factors

This concept is conventionally materiallyoriented, and comes from the schools ofland-use planning, engineering andarchitecture. Physical aspects ofvulnerability, although continually beingbroadened in scope, still refer mainly to

VulnerabilityThe conditions determinedby physical, social,economic, andenvironmental factors orprocesses, which increasethe susceptibility of acommunity to the impactof hazards.

Coping capacityThe means by whichpeople or organizationsuse available resourcesand abilities to faceadverse consequences thatcould lead to a disaster.`

Figure 2.4Interaction of vulnerability factors

Economic

Environmental

Physical Social

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considerations and susceptibilities of location andthe built environment. It may be described as“exposure” or “placed in harm’s way” or “being inthe wrong place at the wrong time”. Physicalvulnerability may be determined by aspects suchas population density levels, remoteness of asettlement, the site, design and materials used forcritical infrastructure and for housing.

Social factors

Social vulnerability is linked to the level of well-being of individuals, communities and society. Itincludes aspects related to levels of literacy andeducation, the existence of peace and security,access to basic human rights, systems of goodgovernance, social equity, positive traditionalvalues, customs and ideological beliefs and overallcollective organizational systems.

Some groups are more vulnerable than others.People less privileged in class or caste structures,ethnic minorities, the very young and very old,and other disadvantaged and marginalizedsegments of the population are more likely to beexposed to greater risk. Gender issues, particularlythe role of women, are also important. In manysocieties, women have a primary responsibility fordomestic life, providing essential shelter and basicneeds. Therefore, women are more likely tobecome more burdened or more vulnerable intimes of crisis.

Public health, concerning physical, mental andpsychological well-being, is a critical aspect ofsocial vulnerability. The disabled, of whom thereare hundreds of millions worldwide, areparticularly susceptible, as their evacuation andcontinued care is severely hampered duringdisasters. Predisposition to infection, exaggeratedexposure to communicable diseases, lack ofdefensive mechanisms represent individualconditions of vulnerability. Physical features in acommunity, such as insufficient basicinfrastructure, especially water supply andsanitation, as well as inadequate health carefacilities and supplies, are also expressions ofincreased vulnerability.

Traditional knowledge systems, as well as culturalaspects such as indigenous beliefs, traditions andways of coping are important determinants in risk

perception. Deeply rooted beliefs that are destiny-oriented or which pose a fatalistic vision ofdisasters can reflect a religious or ideologicallyinherited sense of vulnerability. Such views maypresent a great challenge in moving towards theacceptance of a culture of prevention andprotection.

Social vulnerability is also linked with otherpolitically-oriented societal factors, such as socialpower relations. Institutional organizations andgovernance structures also play an important rolein the level of social vulnerability. Social cohesionand regulation improve coping capacities, whereassocial insecurity increases vulnerability.

Economic factors

Levels of vulnerability are highly dependent uponthe economic status of individuals, communitiesand nations. The poor, a disproportionately femaleand elderly group in most regions, are generallyfar more vulnerable than economically better offsegments of society. This relates both to thepossibility of higher proportional losses among thepoor when a disaster strikes, and to their generallymore limited capacity to recover from disasters.

Economic vulnerability also includes levels ofindividual, community and national economicreserves, levels of debt and the degree of access tocredit, loans and insurance. An economy lackingin diversity is generally more vulnerable. Similarly,inadequate access to critical and basic socio-economic infrastructure, including communicationnetworks, utilities and supplies, transportation,water, sewage and health care facilities, increasepeople’s exposure to risk.

Environmental factors

Key aspects of environmental vulnerability includethe extent of natural resource depletion and thestate of resource degradation. In the same vein, alack of resilience within ecological systems andexposure to toxic and hazardous pollutants areimportant elements that shape environmentalvulnerability. A reduced access to clean air, safewater and sanitation and inappropriate forms ofwaste management, especially in densely populatedand urban environments can deepen levels of

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socio-economic vulnerability. Increasinglyvulnerable environmental conditions such asdiminished biodiversity, soil degradation orgrowing water scarcity can easily threatenfood security for people dependent on theproducts of the land, forests, pastures, andmarine environments for their livelihoods. Apolluted environment also increases people’sexposure to health risks.

As natural resources become more scarce the range ofoptions available to communities becomes more limited,reducing the availability of coping solutions anddecreasing local resilience to hazards or recoveryfollowing a disaster. Over a period of timeenvironmental factors can increase vulnerability furtherby creating new and undesirable patterns of socialdiscord, economic destitution and eventually forcedmigration of entire communities.