Prof. David Alexander University of Florence, Italy RISK assessment and reduction
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 cost
of insured damage .
1500% in the total
cost of disasters
Then (1950s) Now (2009) 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
Impact Emergency isolation During the emergency Emergency response Before the impact Preparations and warning After the impact Period of quiescence Risk mitigation Recovery and reconstruction The Phases of Disaster Disaster risk reduction Civil contingencies management Civil protection Emergency preparedness
Human activity involves risk and benefit A working definition of safety : " a thing is safe if its risks are judged to be acceptable . " A definition of risk for human societies : "the probability that a certain number of people will die in a given impact during a given interval of time."
After Ian Davis (2005) The components of risk Physical disaster Magnitude Frequency Duration Human vulnerability Exposition Location of hazard Environment Resistance Lifestyle and earnings Health Resilience Adjustments Risk reduction activities Preparations for disaster
A person who spends five minutes twice a day crossing a bridge that is at risk of collapse is exposed to that risk for 10/(60x24x7) = 0.00098 of a week .
under threat for a given period of time
at risk to a given extent of possible loss
Different definitions of exposure :
R t = E•R s = E (H•V) R t = total risk E = elements at risk (population, built environment, economic activities) R s = (H • V) = specific risk H = hazard V = vulnerability
RELEASE RATE DOSE RATE EXPOSURE An asset is not vulnerable unless it is threatened by something A hazard is not hazardous unless it threatens something COPING, CAPACITY, CAPABILITY, RESILIENCE RISK HAZARD VULNER- ABILITY ELEMENTS AT RISK
Magnitude Frequency Logarithm of return period Magnitude What does the magnitude-frequency rule mean in real-life situations?
Vertical scales: Hazard : probability of occurrence Vulnerability : potential damage Risk : value of probable costs and losses
Fat-tailed distributions of hazard: big events may be more likely than probability theory suggests Hazard, vulnerability & risk levels
The relationship between hazard and vulnerability is non-linear
VULNERABILITY RISK Intolerable risk and vulnerability Tolerable risk and vulnerability Risk/vulnerability curve Disaster threshold Society sets a level of risk toleration
Low Hazard High environment goods life High Probability Low certainty zero In risk assessment probability and consequence are non-linearly related. high risk medium risk low risk
Society places arbitrary tolerance levels upon risk Cost of risk reduction Risk Arbitrary tolerance levels COST/RISK=1
Number of casualties Cost of retrofitting a building The example of seismic retrofitting unreinforced completely reinforced completely reinforced largely unreinforced Cost of retrofitting a building Cost per life saved
Perceived risk is the assessment of hazard made subjectively by individuals
Risk aversion :
intolerance of a risk that is
perceived to be unacceptably high
desire to reduce it to negligible levels .
Objective risk can be calculated from statistical data on past events. Not all risks can be measured.
A risk classification Voluntary -- Involuntary Chronic -- Catastrophic Common (tolerated) -- Exceptional (dreaded) Injurious -- Fatal Known to those who are exposed -- Unknown to those who are exposed Known to science -- Unknown to science Can be mitigated or controlled -- Cannot be mitigated or controlled Old -- New
HOW PEOPLE PERCEIVE RISK ABILITY TO PERCEIVE RISK EXPERIENCE WITH RISK PROPENSITY TO DENY RISK ACCESS TO INFORMATION
WHETHER RISK HAS BEEN ABATED PEOPLE'S IDEAS ABOUT POSSIBLE DAMAGE AND LOSS
John Adams's "risk thermostat" Balancing behaviour "Accidents" Perceived danger Rewards Propensity to take risks Cultural filter Cultural filter
Filter Perception Culture Decision Action Result Positive Negative Risk Accurate Inaccurate
A model of vulnerability types Vulnerability Total: life is generally precarious Residual: caused by lack of modernisation Newly generated: caused by changes in circumstances Delinquent: caused by corruption, negligence, etc. Economic: people lack adequate occupation Technological, technocratic: caused by the riskiness of technology
Recovery after disaster Physical recovery Buildings, infrastructure, transport, agriculture, etc. The recovery triangle Social and psychological recovery Reducing post- traumatic stress Economic recovery Re-establishing production and economic activities Political, cultural and environmental context .
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 .
Vulnerability in the connection between wall and joist leads to collapse of the structure in an earthquake
Random rubble masonry with powdery lime mortar is a major source of vulnerability in historic and old buildings.
Collapse often begins at roof level if roof structure is too rigid and poorly tied to vertical load-bearing members.
Cornices,parapets and other façade details are particularly vulnerable to damage in earthquakes.
Inadequately constructed frame buildings are vulnerable to progressive collapse
Battering by adjacent buildings with different fundamental periods of vibration.
Esposure Sensitivity Capacity to adapt VULNERA- BILITY Physical dimensions Age of the infrastructure Age and income of the population Demo- graphy Technology Res- ponse Management structure Access to information and technology Exposed res- ources Exposed population Intensity Frequency Location Number Wealth and well being Tax revenues Emergency plans Level of education Information services
Risk identification : what are the risks? Risk assessment or analysis : how serious are the risks and what do they consist of? Risk management : how can risks be reduced? Risk perception and communication : how can risks be communicated to the public, mass media or others? How experts deal with risk:
The essence of disaster management:- To tackle pressing needs with maximum efficiency and speed but with scarce resources and in the absence of necessary information BUT emergency planning is still a young field: it lacks international consensus on standards, procedures, and legal and institutional imperatives
Modern emergency plans are generic ( "all hazards" ):-
adaptable to all emergencies
focussed on the emergencies deemed
most likely to occur in the local area
technical sophistication must
be balanced by ease of use .
Set procedures Co-ordinating plan Spontaneous improvisation Set procedures Co-ordinating plan Spontaneous improvisation Emergency environment Emergency environment
Continuity of production Preservation of organisation's good name Safeguarding of assets Maintenance of market position
CITY DISASTER PLAN Where business continuity management fits in: PROVINCIAL, COUNTY, STATE OR REGIONAL DISASTER PLAN NATIONAL DISASTER PLAN AIRPORT EMERGENCY PLAN INDUSTRIAL CONTINGENCY PLAN COMMERCIAL FACILITIES CONTINGENCY PLAN EMS NETWORK CONTINGENCY PLAN HOSPITAL EMS PLAN HOSPITAL EMS PLAN MEDICAL FACILITY PLAN BCM
Strategic, tactical & operational planning Aftermath Disaster Monitoring prediction & warning Permanent emergency plan Business continuity plan Recovery and reconstruction planning
Construction of operational scenarios of hazard, risk, impact and emergency response Existence of various states of hazard and vulnerabilit y Census of available resources Emergency action plan Processes of constant adaptation of the plan
Initial study Revision Testing Evaluation Activation Disaster Dissemination Information Formulation and updating of plan Stakeholders' input Training
Evaluation Plan Apparent chaos Model Testing Disaster Outcome Feedback Feedback
Initiating the process Planning for business continuity Implementing the plan Managing the crisis
Changing the mindset
Business impact analysis Create the BCM plan Business impact evaluation Objectives -> Risks -> Priorities -> Scenarios
needs to be shortened needs to be lengthened preparation for the next event warning and evacuation recovery and reconstruction repair of basic services emergency management and rescue isolation impact needs to be strengthened Risk reduction and disaster mitigation
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