Risk Assessment of Disasters and Hazards.pptx

Disaster Risk Assessment

1. DISASTER RISK ASSESSMENT MEANING AND CALCULATION OF RISK IDENTIFICATION AND QUANTIFICATION OF POTENTIAL HAZARDS AND VULNERABILITIES POTENTIAL IMPACT OF VARIOUS DISASTERS BY PIYUSH TELANG M.A, NET, SET, PH.D. (PURSUING), CCGIS ASSISTANT PROFESSOR DEPARTMENT OF GEOGRAPHY SIR PARASHURAMBHAU COLLEGE (AUTONOMOUS), PUNE

2. RISK R isk  (or more specifically, disaster risk) is the potential disaster losses (in terms of lives, health status, livelihoods, assets and services) which could occur to a particular community or a society over some specified future time period. It considers the probability of harmful consequences , or expected losses (deaths, injuries, property, livelihoods, economic activity disrupted or environmentally damaged) resulting from interactions between natural or human induced hazards and vulnerable conditions. 

3. CONCEPT OF RISK In general terms , the word Risk means an apprehension or a threat of something untoward happening. In the words of James Neill, the concept of "risk" usually refers to the probability of loss of a 'valued resource '. The word risk is one of the most notable examples of a word with multiple usages in that a risk may refer to a chance or a probability ("risk of exposure"), a consequence or impact ("the risk from smoking"), or a perilous situation ("a hazardous waste plant creates a risk"). Interpretations of the word "risk" have evolved linguistically on the basis of involuntary or voluntary events. For example, "danger" is often used to describe an involuntary event, whereas " peril“ (Great danger) may be used to describe a voluntary event. Despite the widespread use of the word, no single definition can claim to be universal , and there is little likelihood of a common understanding developing without some conscious effort at establishing a consensus .

4. From general usage, the term risk has come to be applied more specifically , in that the nature of risk differs with the type of activity under consideration. For example, investment in mutual funds (MFs) is a 'risky' venture. If stock prices fall by 10%, market risk says that MFs are likely to see erosion in their net asset value (NAV-rupee value of a single MF unit, calculated on the value of the underlying assets of the fund less its liabilities, divided by the number of units outstanding, disclosed at the end of each trading day). Usage of the word "risk" in the context of health and environmental risks integrates two ideas; firstly that the situation being discussed has the potential for detrimental consequences , and secondly that there is some improbability associated with the circumstances . There is uncertainty whether a hazardous event will occur; when or where it will occur, who or what will be affected; and the magnitude of the consequences. "Risk", in this sense, includes both the possibility and the character of the detrimental event. CONCEPT OF RISK

5. A statement of risk based solely on one aspect of risk, such as the probability of occurrence, has been referred to as a single dimensional risk. Financial or insurance risks are primarily single dimensional risks , as are statements on health risks that are restricted to the chance of occurrence (Hamilton and Viscusi , 1999 ). In the specific context of disaster management , risk implies application of specialist knowledge on the part of professionals to forewarn of disasters accurately and anticipate the risks involved in citing, land use management and project planning decisions in hazard prone areas so as to prevent/reduce impact of impending disaster(s ). Thus in disaster terminology, Risk is defined as "the likelihood of a specified undesired event occurring within a specified period or in specified circumstances. It may be a frequency or a probability. Often it is expressed in mathematical terms as : Risk = f (frequency or probability, consequences) CONCEPT OF RISK

6. Presentation of Risk Risk is a matter of precise quantification. Risk may be expressed in terms of average expected losses from a given hazard to a given element at risk, over a specified future time period; For example, as; "25000 lives lost over a 30 year period or as 75000 houses experiencing heavy damage or destruction within 25 years or alternatively, on a probabilistic basis, as a 75% probability of economic losses to property, exceeding 50 million dollars, in the town of Puerto Neuvo , within the next ten years ". The term specific risk is used to refer to risk or loss estimations of either type which are expressed as a proportion of the total; the first two examples might also be expressed as: 10% of the total population killed by natural hazards within 30 years or 50% of houses heavily damaged or destroyed in the next 25 years. Specific risk is also used for financial losses to property where is usually refers to the ratio if the cost of repair or reinstatement of the property to the total cost of replacement. Frequently, the shorter-term risk is used to refer to what are strictly 'specific risks .

7. Precise quantification of risk, however, is difficult. At best, a gross estimation of risk is possible, taking, for example, number of deaths and the number of people exposed to a hazard. Such crude estimates give only a limited idea of the likely damage from a hazard for different peoples at different places or even the probability of its occurrence. For example:"... the probability of being killed in an earthquake in Iran during any one year is obtained from the total number of killed by earthquakes in Iran this century (120,000) divided by 90 years. This gives an average of 1, 300 people killed annually . The population of Iran, currently (55 million) averaged over the past ninety years is less than 30 million, so the average probability of being killed in an earthquake is given as one in 23,000.6..." Presentation of Risk

8. There are different ways of dealing with risk, such as: Risk Acceptance : an informed decision to accept the possible consequences and likelihood of a particular risk. Risk Avoidance : an informed decision to avoid involvement in activities leading to risk realization. Risk Reduction  refers to the application of appropriate techniques to reduce the likelihood of risk occurrence and its consequences. Risk Transfer  involves shifting of the burden of risk to another party. One of the most common forms of risk transfer is Insurance.

9. Elements at Risk

10. The expected loss from a given hazard and related depends upon the hazard intensity, population exposed and vulnerability of housing stocks. A simplified way of projecting the inter-dependencies of these factors and risk at a place is : Risk at any place = [(Hazard x Vulnerability) x exposure] / Capacity, where various terms are defined as Risk is combination of probability of an event and its negative consequences Hazard is a threatening event i.e. Earthquakes/Wind storm/ Cyclones/Floods/Landslides Vulnerability is Characteristics and circumstances of a community, system or asset that make it susceptible to the damaging effects of a hazard Exposure is in terms of People, buildings, businesses, infrastructure Capacity is combination of all the strengths, attributes and resources available within a community, society or organization

11. * VULNERABILITY Vulnerability describes the characteristics and circumstances of a community, system or asset that make it susceptible to the damaging effects of a hazard. There are many aspects of vulnerability, arising from various physical, social, economic, and environmental factors. Examples may include: poor design and construction of buildings,  inadequate protection of assets, lack of public information and awareness, limited official recognition of risks and preparedness measures, and disregard for wise environmental management. 

12. Vulnerability varies significantly within a community and over time 1. Physical Vulnerability  may be determined by aspects such as population density levels, remoteness of a settlement, the site, design and materials used for critical infrastructure and for housing (UNISDR). Example: Wooden homes are less likely to collapse in an earthquake, but are more vulnerable to fire . 2. Social Vulnerability  refers to the inability of people, organizations and societies to withstand adverse impacts to hazards due to characteristics inherent in social interactions, institutions and systems of cultural values. It is linked to the level of well being of individuals, communities and society. It includes aspects related to levels of literacy and education, the existence of peace and security, access to basic human rights, systems of good governance, social equity, positive traditional values, customs and ideological beliefs and overall collective organizational systems (UNISDR). Example :  When flooding occurs some citizens, such as children, elderly and differently-abled, may be unable to protect themselves or evacuate if necessary.

13. 3. Economic Vulnerability : The level of vulnerability is highly dependent upon the economic status of individuals, communities and  nations. The poor are usually more vulnerable to disasters because they lack the resources to build sturdy structures and put other engineering measures in place to protect themselves from being negatively impacted by disasters.  Example: Poorer families may live in squatter settlements because they cannot afford to live in safer (more expensive) areas. 4. Environmental Vulnerability :   Natural resource depletion and resource degradation are key aspects of environmental vulnerability.

14. Vulnerability Factors Population Displacement Urbanization Gender Economic Factors Geographical Factors Livestock Vulnerability

15. It can be best explained by Disaster Risk = Hazard × Vulnerability/Capacity The relationship between these four components, indicate that each of the three variables that define risk - the hazard, the elements exposed and their vulnerability are of equal value. Reducing any one or more of the three contributing variables will lessen the risk to a community. In reality, however, there is little opportunity to reduce the hazard component, therefore, only the vulnerability and the elements at risk will vary. When hazard and vulnerability are high, it will cause disaster but when capacity is present, it will decrease the impact. Hence, to reduce the risk of a disaster, 1) Decrease the vulnerability of the community; and 2) Increase the capacity of the community

16. Risk management Risk mitigation (i.e. moderating the severity of a hazard impact) is the main objective of risk management. It aims to reduce the physical and economic impacts of an event and limit the human, material, economic and environmental costs of an emergency or disaster. Therefore, it is necessary to have good information on the costs of natural disasters. These are estimated with a risk analysis . Following the risk analysis, the risks are evaluated in a risk assessment process to decide whether they are tolerable/acceptable. Both risk analysis and assessment are normally part of an integrated risk management process and produce crucial information that is relevant to decision makers for identifying viable options for risk reduction.

17. WHAT IS RISK ASSESSMENT? Risk assessment is a process to determine the nature and extent of such risk, by analyzing hazards and evaluating existing conditions of vulnerability that together could potentially harm exposed people, property, services, livelihoods and the environment on which they depend. A comprehensive risk assessment not only evaluates the magnitude and likelihood of potential losses but also provides full understanding of the causes and impact of those losses. Risk assessment, is an integral part of decision and policy-making processes and requires close collaboration among various parts of society.

18. Besides the estimation of potential losses and their impact, risk assessment allows for the determination of the acceptable level of risk , defined as the level of losses that is acceptable without destroying lives, national economy or personal finances . Once the current and acceptable levels of risk are determined, disaster risk reduction plans and strategies could be revised or developed so that they have the measurable goal of reducing the current risk to acceptable levels. For countering existing disaster risk systematically, for example by formulating a comprehensive DRR (Disaster Risk Reduction) policy, developing land-use plans or putting in place insurance mechanisms to transfer non-reducible risks, the knowledge and understanding provided by a comprehensive risk assessment are fundamental. Furthermore, when the plans are being implemented, periodic evaluations of risk provide an explicit indication of progress in risk reduction. They help to evaluate the effectiveness of disaster risk reduction efforts and make the necessary corrections to the plans and strategies. WHAT IS RISK ASSESSMENT?

19. Disaster Risk Reduction (DRR) Disaster Risk Reduction ( DRR) refers to the key set of activities aimed at reducing the impact of disasters and promoting a disaster resilient society . DRR efforts cannot be pursued without an understanding of the disaster risks facing the region or community. Hazard , Vulnerability and Risk Assessment is an important tool for developing the contextual understanding of disaster risks.

20. Hazard vulnerability and Risk analysis  falls into two general categories:   Quantitative analysis Qualitative analysis . Utilizes mathematical and/ or statistical data Relies on mathematical and/or statistical data A numerical description of disaster risk Defined terms (words) to describe and categorize the hazard risk likelihood and consequence value outcomes. Provide specific data points Considers ranges of possible values for which each qualifier is assigned. E.g. – dollars, probability, frequency or number of injuries/fatalities E.g. - High: A very likely event, occurring frequently or with a high probability. Medium: a moderately likely event, occurring occasionally or with a moderate probability. Low: an unlikely event, occurring rarely or with a low probability. Cost and time prohibitive and often not necessary, to determine the exact quantitative measures  Much easier to determine and typically require less time, money, and, most important, expertise, to conduct.  Not most commonly in used. Most commonly used method of assessment in practice.

21. Hazard Assessment The process of Hazard assessment involves the identification and systematic ranking of all hazards that might affect a location. It involves a two-step process;

22. Hazard Frequency Hazard Frequency  data indicates the frequency or the number of times a particular hazard event occurs in a specified period of time. For instance, the frequency of auto accident deaths in the United States is roughly one death per 81 million miles driven ( Dubner and Levitt 2006). Sources of Hazard frequency data include historical data including governmental reports, statistical or archival records including media archives, Focus Group Discussions with elderly in the communtiy , existing disaster management plans, sector wise records like that of transportation, public works , local police, fire departments etc. All other sources of hazard data that could include detailed information about date of occurrence, magnitudes, corresponding damages, and further evidence of past disasters in the community or state. The hazard frequency data is sometimes depicted in maps by few agencies like the Centre for Research on the Epidemiology of Disasters (CRED).

23. Probability data Probability refers to single-event scenario, where the value is expressed between zero and one. Zero signifies a zero percent chance of occurrence while one signifyies a certain occurrence. Examples of probability data include Earthquake Zonation mapping, flood zone mapping etc. which indicates the likelihood of occurrence of events but might not have happened yet. In disaster management, hazards are expressed as probabilities. For example, if an area has experienced four flood events in the past 200 years where floodwaters reached 20 feet above the base flood elevation, then this severity of flooding has a one-in-fifty chance of occurring in any given year, or a probability of 2 percent, or 0.02, each year.

24.   The likelihood of a particular event giving rise to an emergency or disaster event could be expressed using a qualitative system of likelihood: Certain : having greater than 99 % chance of occurring in a given year (one or more occurrences per year) Likely : having a 50–99 % chance of occurring in a given year (one occurrence every one to two years)  Possible : 5–49 % chance of occurring in a given year (one occurrence every two to twenty years) Unlikely : 2–5 % chance of occurring in a given year (one occurrence every twenty to fifty years) Rare : 1–2 % chance of occurring in a given year (one occurrence every fifty to one hundred years)

25. Event Tree One important component of hazard analysis is the identification of subsequent hazards that might arise as a result of the hazard occurring in a particular community/ location. 

26. Fault tree Fault Tree and Event Trees are in principle similar. In event tree as we begin with the primary hazard and imagine the consequences. Fault Trees are usually made as an analysis of an adverse event that has already happened. Fault Trees begin with the impacts or consequences and trace back to the possible initiating event (hazard) that could have triggered the impacts .

27. Vulnerability assessment and approaches Vulnerability is highly complex and contextual. The contextual nature of vulnerability and community being the central theme for vulnerability makes the concept extremely dynamic as the community characteristics might change over time. There are mainly five types of vulnerabilities : Physical Vulnerability Social Vulnerability Economic Vulnerability Environmental Vulnerability Institutional vulnerability 

28. Vulnerability Assessment There are four main clusters of assessing vulnerabilities: 1) Laundry List approach – which tries to list the elements at risk. This includes the structural fragility of infrastructure, the vulnerability of people etc.   2) The Taxonomy Approach – that forms taxonomies of vulnerable population (like A-B-C Classification of buildings depending on their structural strength, classification of population in gender, social status, access to power, physical abilities etc.)   3) Situational Approach – is to look at vulnerability to certain specific situations like in case of earthquake or in case of a policy change (like change in currency denomination).   4) Community Based Approach – When communities determine their own vulnerability and their capability which could utilize any of the above three approaches nested into this approach. Often the pre-existing inequalities within a community, get reinforced when community based or community led vulnerability analysis is done.

29. Essential elements of vulnerability assessment   (a) Assessment Purpose and Scope  including assessment purpose, expected outcomes, existing targets/ goals, the time frame and geographical scope, key stakeholders and resource availability and requirement   (b) Assessment of the sensitivity and exposure  (the potential impact on the socio-economic and ecology of systems) due to the magnitude of the stress/ hazard, the existing local stresses (including routine risks) and the differences in how individuals or institutions might be affected by the hazards under assessment.   (c) The Adaptive Capacity  that assess the ability of communities to cope with and respond to the hazards (along with the routine risks faced). These include the effectiveness of social networks and their access, the local knowledge/ customs/ practices that helps to cope with the stress/ hazard, community awareness towards the hazards, their ability to mobilize, plan, respond to and learn from the hazard, access to material resources and financial resources, along with access to information etc.

30. Assessment is mainly qualitative but could be converted to a quantitative scale. For instane the vulnerability assessment carried out by Australian Emergency Management Society suggests a logarithmic table quantifying the qualitative assessment into four levels of susceptibility and four levels of resilience (Very Low, Low, Medium, and High). Vulnerability results due to the combination of susceptibility and resilience. The scale is as follows: Susceptibility   is the exposure to danger and   Resilience   is the capacity to recover , while vulnerability is the predisposition of system to suffer damage.   Further, the factors that needs to be assessed for each hazard is also specified.

31.  Socio economic vulnerability assessment There are few useful models available to carry out the socio-economic vulnerability assessment Household economy approach (HEA ) Individual household model ( IHM) Household livelihood security analysis (HLSA). The Household Economy Model for instance could help in performing an outcome analysis by investigating how baseline access to food and income could be affected by particular hazard.

32. Risk Assessment and Approaches The scientific quantification of risk based on hazard, vulnerability and capacity analysis is called  Risk Assessment . It involves gathering data of various hazards and on the basis of statistical analysis, predicting the probability of their occurrence and impact in future . The understanding of the causes of disasters and their probable impacts is very important for conducting proper risk assessment. Once hazard and vulnerability assessment are completed , risk assessment for disasters may be evaluated.

33. Risk Assessments must be- (1)  Multi-hazard : as the same geographical area might be threatened by multiple hazards. It is necessary to identify the range of hazards and impacts on the current infrastructure and planned infrastructure, on different groups of people, and their coping caapcity to bounce back from various hazards   (2)  Multi- sectoral : Different hazards will impact to different sectors differently. Consequences of drought and that of earthquake to the building stocks would be different. Likewise consequences of drought and earthquakes on agriculture would also be completely different.   (3) Multi-level : The risk assessment could be carried out at the ward level, that is integrated to the district level and later the state finally leading to the country’s disaster risk assessment   (4) Multi-stakeholder : involving relevant stakeholders   (5) Multi-phase : considering actions for response, recovery, mitigation, and prevention.  

34. Types of Risk Assessment (1) Qualitative Assessment – describing risks into categories as high, medium and low based on expert judgment   (2) Semi-Quantitative – expressing risks in terms of indices based on relative rankings or weights assigned by means of certain criteria   (3) Quantitative : expressing risk in quantitative terms as probabilities or as expected losses. Quantitative assessment of risk could be:   a. Probabilistic : expressed as probabilities (0-1) for having predefined loss   b. Economic  (as a quantification of expected losses in monetary terms) and the following calculated:   i. Probable Maximum Loss- the largest loss possible for a particular time period ii. Average Annual Loss- The loss when average of losses per year is calculated iii. Loss Exceedance Curve- a risk curve plotting the losses against probability for many events  

35. c. Population risk  (as a quantification of the risk to population)   i. Individual risk- risk of fatality/ injury to identified individuals in the impact area   ii. Societal risk- individual risk extrapolated to a society     Types of Risk Assessment

36. An example of quantitative assessment of risk is the HRVA (Hazard Risk Vulnerability Analysis) Toolkit, which is a comprehensive method utilized for such evaluation. Based on the vulnerability and frequency of occurrence, a matrix of risk for the hazards is developed.

37. Plotting of Vulnerability curves and Fragility curves by utilizing damage functions for earthquake hazard is an instance of quantitative assessment of risk. Regression analysis of damage to woodframe buildings in 1994 Northridge Earthquake Source: (Porter, 2016)

38. An example of semi-quantitative assessment is utilizing GIS (Geospatial Information System), where multi-criteria techniques are utilized. The risk identified qualitatively when represented in spatial method utilizing risk indices by combining vulnerability index and hazard index is such a technique .

39. Necessity of risk assessment Risk Assessment provides tremendous scope for interventions towards Disaster Risk Reduction. The Sendai Framework for Disaster Risk Reduction (SFDRR) has Understanding Risk as its first priority. SFDRR also states that no new risk must be created by any new development project, thereby making risk assessment an important parameter in the design and implementation of development programmes. Investments in development projects have repeatedly been negated by losses due to natural disasters especially in hazard prone areas including the recent Fukushima nuclear tragedy due to the strong earthquake that rocked Japan. A cost benefit analysis could be utilized as a trustworthy tool post a proper risk assessment.