Vulnerability to Disasters

VulnerabilityAnalysis

David AlexanderUniversity College London

The components of risk

Physical disaster

Magnitude

Frequency

Duration

Human vulnerability

ExposureLocation of hazard

Environment

ResistanceLifestyle and earnings

Health

Resilience

Adjustments

Risk reduction activities

Preparations for disaster

After Ian Davis (2005)

Uncertain future:

long-term trendsclimatechangecapacity to adapt

Livelihoods:security and

wealth generation

Hazardsand risks:disaster

preparedness

Governance:democratic participation in decision

making

RESILIENCE:managing risks

adapting to changesecuring resources

Vulnerability is constructed socially

• it is mainly the result of social,economic, political and culturalfactors in decision-making

• it is becoming harder to reduce.

Trends in disaster losses are unsustainable.In the second half of the 20th century

the world experienced increases of:

• 250% in the number of recorded disasters

• 500% in number of disasters with victims

• 500% in the number of affected people

• 1640% in the costof insured damage.

• 1500% in the totalcost of disasters Disasters

1900-2010

Then (1950s) Now (2013)

Under-reporting of disasters

More complete recording

Counting only direct effects

Quantifying indirect effects

Smaller population of hazardous places

Larger population, greater densities

Less inequality Growing inequality and

marginalisation

Less fixed capital at risk

Relentless accumulation of fixed capital

Simpler socio-economic networks

More complex networks

• social and technologicalcomplexity are increasing

• fixed capital is being accumulated

• the world is becoming more polarised

• urbanisation and thegrowth of "mega-cities".

Societies are becomingmore vulnerable

Vulnerability approach

• people, not physical forces, are theprincipal cause of risks and disasters

• focus on reducing community vulnerability

• "soft" rather than "hard" approaches

• "bottom-up" (grass roots) approach.

A sample of the annualpattern of casualtiesin natural disasters

A sample of the annual patternof losses in natural disasters

Death

tolls

Economic losses

Differential impact of disasters

Developing countries anddepressed urban areasof developed countries

Developed countries andthe richest cities ofthe developing world

What exactly is vulnerability?

RiskCivil defence

Hazard

Vulnerability

Threat

Exposure

Response

Mitigation Protection

Civil protection

Vulnerability is...

• the potential degree of loss resultingfrom a particular hazard or setof hazards of a given magnitude

• the potential for harm

• something that is constructed socially

• the inverse of capability(coping, resilience).

UNESCO / UNDRO (1982) Definitionsof Hazard and Risk Terminology

Vulnerability (V): the degree of lossto a given element or set of elementsat risk resulting from the occurrenceof a hazardous phenomenon of a givenmagnitude. It is expressed on a scalefrom 0 (no damage) to 1 (total loss)

Vulnerability

Total: life isgenerallyprecarious

Residual: caused bylack of modernisation

Newlygenerated:caused bychanges in

circumstances

Delinquent:caused bycorruption,negligence,

etc.

Economic:people lackadequateoccupation

Technologicaltechnocratic:caused by

the riskinessof technology

Primary• cause and effect

Secondary• interaction of causes

• coincidences

Complex• complicatedinteractions

VULNERABILITY

(Hazard x Vulnerability x Exposure)Resilience= Risk

[ → Impact → Response]

Hazard x (Vulnerability / Resilience)[x Exposure]

= Risk[ → Impact → Response]

....alternatively:-

VulnerabilityHazard

An asset is notvulnerable unlessit is threatenedby something

A hazard is nothazardous unless

it threatenssomething

RISKExtremeevents

Elementsat risk

Resilience

Exposure

Disaster management

Emergency management

Crisis management

Risk management

Vulnerability management

Hypothetical

Concrete Concentrated

Diffuse

Vert

ical axis s

cales:

Hazard

: pr

obability o

f oc

curr

enc

eVulne

rability: po

tent

ial damage

Risk: va

lue o

f pr

obable c

osts

and

los

ses

Severity

Risk as productof hazard andvulnerability

Total annualpredicted costsand losses

Risingvulnerabilitywith increasingseriousness ofpotentialconsequences

Falling hazardwith diminishingprobability ofoccurrence

Fat-tailed distribution

The role ofperception

Riskamplification

factors

Riskmitigationfactors

Totalvulnerability

Risk perceptionfactors- +

positivenegative

DIALECTIC

Causes of disasternatural geophysical,technological, social

Historysingle andcumulativeimpactof pastdisasters

Humancultures

constraintsand

opportunitiesIMPACTS

Adaptationto risk

RESILIENCE

Diffusion of information

Perceptual filter

Cultural filter

Emergency not decoded

Emergency decoded

Ignorance

Imagesof reality

Symbolicconstructions

Enlightenment

Long term

Short term

Emic components

Etic components

METAMORPHOSISOF CULTURE

Experiences of culture[mass-media and consumer culture]

Accumulated cultural traits and beliefs

Inherited cultural background

Ideological(non-scientific)interpretations

of disaster

Learned(scientific)

interpretationsof disaster

Valuesystem

Familyculture

Workculture

Peergroupculture

Personalculture

National culture

Regional culture

Technologyorganisationssafety culture

Ethnologysocieties

community culture

Psychologyethnic groups

individual culture

Communicationmass media

multicultural societies

Filter

Perception

Culture

Decision

Action

Result

Positive Negative

Risk

Accurate Inaccurate

Technologyas risk

mitigation

Technologyas a source

of vulnerability

Research,development

and investmentin technology

individualfamilypeer grouporganisationcommunitysocietyinternational C

ultu

ral filter

Sociocentrism Technocentrism

Culturalfilter

Riskmanagementpractices

Benign

Malignant

Technologyas a source ofrisk reduction

Technology asan inadvertentsource of risk

Technologyas a deliberatesource of risk

Ceaselessdevelopmentof technology

Large disaster

Increasedexpenditure

Return ofcomplacency

Risk-expenditure cycle

Deaths, injuries,hardship, damage, disruption

Review

Reduced riskNo disaster

Reducedexpenditure

Increased risk

Disaster

Public outcry Rhetoric

Logic

Laws

Safety culture

The evolution ofa safety culture

What exactly is resilience?

Vulnerability = 1 / resilience

Resilience: mechanisms for avoidingimpacts or absorbing them by coping

Coping strategies:• indigenous• imported

What is resilience [resiliency]?

• a combination of resistance andadaptation (coping, capacity, capability)

• ability to maintain livelihoods and tenorof life in the face of disaster shocks

• local autonomy and self-sufficiency.

Attitud

e

Theingredientsof resilience

• robustness: resist stresswithout loss of function

• redundancy: ability to continuefunctioning during periods of disruption

• ingenuity: ability to identifyproblems and mobilise resources

• rapidity: ability to satisfy objectivesand priorities so as to reduce losses.

The four dimensions of RESILIENCE:-

Recoveryand

reconstruction

Mitigationandresilience

Preparationandmobilisation

Emergencyintervention

Quiescence

Crisis

The disastercycle

needs to be shortenedneeds to belengthened

preparationfor the

next event

warningand

evacuation

recovery andreconstruction

repair ofbasic

services

emergencymanagementand rescue

isolation

impact

needs to bestrengthenedRisk reduction and disaster mitigation

Conclusions

Disasteropens awindow ofopportunityfor positivechange andgreatersecurity

The optimistic view

What is sustainable vulnerability reduction?

• it is centred upon the local level(but is harmonised from above)

• through consultation it has the supportand involvement of the population

• plans tackle all the phases of thedisaster cycle - in an integrative way

• it is a fundamental, every-day servicefor the population and is taken seriously.

HUMANCONSEQUENCES

OF DISASTER

“ORTHODOX” MODEL

PHYSICALEVENT

HUMANVULNERABILITY

“RADICAL CRITIQUE” (K. HEWITT et al.)HUMAN

CONSEQUENCESOF DISASTER

HUMANVULNERABILITY

PHYSICALEVENT

PROPOSAL FOR A NEW MODEL

HUMANCONSEQUENCES

OF DISASTER

HUMANVULNERABILITY

CULTURE HISTORYPHYSICALEVENTS

CONTEXT & CONSEQUENCES

Resilience against disasters:Ten suggestions for action

Organisednon-structural

protection

Enhancedstructuralprotection

Planning,warning andpreparedness

Fusion withsustainability

agenda

Policy outcomes

Protection strategy

Tell people what to do in a crisis.

Develop urban search andrescue capacity on site.

Reduce non-structural aswell as structural hazards.

Plan flexibly.

Create networks.

Encourage governance.

Adapt and disseminate good practice.

Ensure that Disaster Risk Reduction(DRR) programmes are sustainable

Create a strategy for recoveringfrom the next disaster.

Create a culture of resilienceagainst disasters.

...and avoid themyth of panic:

it should not betreated as a

relevant factorin emergency

planning

Exposure Sensitivity

Capacity toadapt

VULNERA-BILITY

Dimensions ofvulnerability:• exposure• sensitivity• capacityto adapt

Components ofthe dimensions

Measures of the components

Vulnerability• Dimensions• Components• Measures

Exposure Sensitivity

Capacityto adapt

VULNERA-BILITY

Physical dimensions

Age of theinfrastructure

Age andincome of the

populationDemo-graphy

Technology

Res-ponse

ManagementstructureAccess to

information andtechnology

Exposedres-

ources

Exposedpopulation

Intensity

Frequency

Location

Number

Wealth andwell being

Taxrevenues

Emergencyplans

Level ofeducation

Informationservices

Analysis

• registered• archived• forgotten• ignored

Vulnerabilitymaintained-

• utilised• adopted• learned

Disasterriskreduced

+

LessonsPast

events

The process ofdisaster riskreduction(DRR)

A guide to recognizingvulnerability in the field

How to estimate vulnerability in the field

Elements:

• buildings and physical structures

• lifelines and infrastructure

• patterns of activity

that put people at risk

• perceptions of hazard

• concentrations and patterns

of elements at risk.

NB: Most of the following slides showpost hoc indications

of vulnerability.

Squatter settlementin Bangladesh Flood level

Normal river level

Rather than mitigating the sources ofvulnerability to disaster, globalisation ismaintaining, exporting and reinforcingthem by its divide-and-rule strategies

PeruvianAndes,EasternCordillera

Rock debrisslide-fall

Destroyedhouses

The 'megacity' problem

Tehran

Tehran

Kathmandu

Kathmandu

İstanbul

İstanbul

Tokyo

Poor buildingquality

(low seismicresistance)

Proximityto epicentreand faultrupture

Topographicamplification

Sedimentaryamplification

Q E

T S

Concentrationof casualties

C

C = f { E,Q,S,T }

Deaths

Injuries

Q E

T S

Vulnerabilityto earthquakes

'Window' of active faultwith mullion slickensides

and normal (verticaldownwards) displacement

Seismic consolidation-compaction subsidence

at fault boundary

Vulnerability in theconnection betweenwall and joist leadsto collapse of the structure in anearthquake

Random rubblemasonry withpowdery limemortar is amajor sourceof vulnerabilityin historic andold buildings.

Collapse often beginsat roof level if roofstructure is too rigidand poorly tied tovertical load-bearingmembers.

Cornices,parapetsand other façadedetails areparticularlyvulnerable todamage inearthquakes.

[four people werecrushed to death here]

Inadequatelyconstructedframe buildingsare vulnerable toprogressive collapse.

Stairwells areoften the mostvulnerable partof the buildingduringearthquakes,and the firstpart that peopleuse as they tryto escape.

Zone of interference

Differential movements

Pre-earthquakeroof-line

Replacementstonework

Self-protection during earthquakes andtornadoes is NOT fostered by the myth thatit is safe to shelter under desks and tables.

Rim of caldera blastedapart in A.D. 79

Cone activeA.D. 1631-1944

Europe's most densely populated municipality(population 80,000 in 4.5 sq.km)

0 1 2 3 4 5 km

Tyrrhenian

Sea

Mt Vesuvius

Portici

Ercolano

( and Herculaneum)

Mt Somma

Naples

Barra

Pompeii

Torre

del Greco

Torre

Annunziata

San Giuseppe

Vesuviano

Main lava flow, pyroclastic flow

and lahar hazard areas

Densely

settled areas

Tephra

fallout areas

Population at riskmin: 650,000

max: 3.1 million

Somma-Vesuvius Portici (pop. 80,000)

1631pyroclastic flow

1631 pyroclastic flow(4000 dead in Portici)

recent flank cone

19th centurylava flows

homes of 1-3 million people

MountVesuvius

Forward thrust

Nodes arefirst to fail

Columnsshear throughunder sustainedpressure

Landslide direction

Spontaneoustoppling failure

in unconsolidatedsands

Backwardrotation of

toppled blocks

Bedrooms wherefour people died

Spontaneous total failure of foundations

Spontaneous totalfailure of r-c frame bldg

...with someforward thrust

Tranquil Alpine scene

...with debris flow

...and severalbrand-new hotelsat its foot

...and bouldersthat went

right through!

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