Natural and Human Disasters Unit 7 ReviewDisaster Risk: Assessment & Management

Key Concepts and Definitions

• Disaster a serious disruption of the functioning of a community or society, causing widespread human, material, economic, or environmental losses that exceed the ability of the affected community or society to cope using its own resources
• Hazard a potentially damaging physical event, phenomenon, or human activity that may cause loss of life, injury, property damage, social and economic disruption, or environmental degradation
• Risk the probability of harmful consequences or expected losses (deaths, injuries, property, livelihoods, economic activity disrupted, or environment damaged) resulting from interactions between natural or human-induced hazards and vulnerable conditions
  • Calculated using the formula: $Risk = Hazard \times Vulnerability \times Exposure$
• Vulnerability the characteristics and circumstances of a community, system, or asset that make it susceptible to the damaging effects of a hazard
• Exposure the situation of people, infrastructure, housing, production capacities, and other tangible human assets located in hazard-prone areas
• Resilience the ability of a system, community, or society exposed to hazards to resist, absorb, accommodate, adapt to, transform, and recover from the effects of a hazard in a timely and efficient manner
• Mitigation the lessening or limitation of the adverse impacts of hazards and related disasters, often through strategies and measures taken in advance

Types of Disasters and Their Impacts

• Natural disasters caused by natural hazards (earthquakes, tsunamis, volcanic eruptions, landslides, hurricanes, floods, wildfires)
  • Geophysical disasters originate from solid earth (earthquakes, tsunamis, volcanic activity)
  • Hydrological disasters caused by deviations in the normal water cycle (floods, landslides, wave action)
  • Meteorological disasters caused by short-lived, micro- to meso-scale extreme weather and atmospheric conditions (storms, extreme temperatures)
  • Climatological disasters caused by long-lived, meso- to macro-scale atmospheric processes (droughts, wildfires)
• Human-induced disasters caused by human activities or choices (technological accidents, environmental degradation, pollution, conflict)
  • Technological disasters caused by failure of a technology system (industrial accidents, transportation accidents, oil spills)
  • Environmental disasters caused by human activities that degrade the environment (deforestation, desertification, pollution)
• Impacts of disasters can be categorized as direct (physical damage, deaths, injuries) or indirect (economic losses, social disruption, environmental degradation)
• Cascading disasters initial disaster triggers a sequence of secondary hazards and failures, amplifying impacts (2011 Tōhoku earthquake and tsunami led to Fukushima nuclear disaster)

Risk Assessment Methodologies

• Risk assessment the process of identifying, analyzing, and evaluating risk to inform risk management decisions and actions
• Hazard identification the process of recognizing the existence of a hazard and defining its characteristics (location, intensity, frequency, probability)
  • Historical analysis examining past occurrences of hazards to identify patterns and trends
  • Hazard mapping creating visual representations of hazard-prone areas based on historical data, scientific modeling, or expert opinion
• Risk analysis the process of comprehending the nature of risk and determining the level of risk
  • Qualitative risk analysis prioritizing risks for further analysis or action by assessing their probability of occurrence and impact
  • Quantitative risk analysis numerically analyzing the combined effect of identified risks, using techniques like probabilistic modeling and sensitivity analysis
• Risk evaluation the process of comparing the results of risk analysis with risk criteria to determine whether the risk and/or its magnitude is acceptable or tolerable
  • Risk criteria the terms of reference against which the significance of a risk is evaluated (regulatory requirements, societal values, economic considerations)
• Risk assessment outputs inform the development of risk management strategies, policies, and measures to reduce disaster risk

Vulnerability Analysis

• Vulnerability analysis the process of identifying, quantifying, and prioritizing the vulnerabilities in a system
• Physical vulnerability the susceptibility of the built environment (buildings, infrastructure, critical facilities) to damage from hazards
  • Structural vulnerability the susceptibility of buildings and infrastructure to damage based on their design, construction, and maintenance
  • Non-structural vulnerability the susceptibility of building contents and systems (equipment, piping, electrical systems) to damage
• Social vulnerability the susceptibility of social groups to the impacts of hazards, influenced by factors like age, gender, health, education, and marginalization
  • Demographic vulnerability certain demographic groups (elderly, children, disabled) are more susceptible to harm from hazards
  • Economic vulnerability populations with limited financial resources are less able to prepare for, respond to, and recover from disasters
• Environmental vulnerability the susceptibility of ecosystems and natural resources to degradation from hazards and human activities
  • Ecosystem vulnerability the susceptibility of ecosystems (wetlands, forests, coral reefs) to damage and loss of function
  • Resource vulnerability the susceptibility of natural resources (water, soil, biodiversity) to depletion or degradation
• Vulnerability assessment techniques include GIS-based spatial analysis, social vulnerability indexing, and participatory vulnerability assessment

Hazard Mapping and Modeling

• Hazard mapping the process of creating maps that identify areas affected by one or more hazards, often based on historical data, scientific modeling, or expert opinion
  • Single-hazard maps depict the spatial extent and intensity of a single hazard (flood hazard map, seismic hazard map)
  • Multi-hazard maps combine information on multiple hazards to identify areas at risk from multiple sources
• Hazard modeling the process of using mathematical and computational tools to simulate the behavior and potential impacts of hazards
  • Deterministic modeling uses physical laws and equations to predict the behavior of a hazard based on specific input parameters (flood inundation modeling, wildfire spread modeling)
  • Probabilistic modeling incorporates uncertainty and randomness to estimate the likelihood and potential consequences of hazard events (seismic hazard assessment, hurricane risk modeling)
• Remote sensing the acquisition of information about an object or phenomenon without physical contact, often using satellite imagery or aerial photography
  • Used for hazard identification, vulnerability assessment, and post-disaster damage assessment
• Geographic Information Systems (GIS) computer-based tools for capturing, storing, analyzing, and displaying spatial data
  • Used for hazard mapping, vulnerability analysis, and risk assessment
• Hazard maps and models inform land-use planning, building codes, and emergency management decisions to reduce disaster risk

Risk Management Strategies

• Risk management the systematic approach to identifying, assessing, and reducing risks to acceptable levels
• Risk reduction measures actions taken to lessen the likelihood, negative consequences, or both, associated with a risk
  • Structural measures physical constructions or engineering techniques to reduce hazard impacts (levees, seawalls, earthquake-resistant buildings)
  • Non-structural measures policies, awareness, knowledge development, and methods that reduce risk without physical constructions (land-use planning, building codes, public education)
• Risk transfer the process of shifting the financial burden of particular risks from one party to another, often through insurance
  • Disaster insurance provides financial protection against losses from natural or human-induced hazards
  • Parametric insurance payouts triggered by the occurrence of a pre-defined event, such as an earthquake of a certain magnitude or a hurricane of a certain category
• Risk retention the acceptance of the potential losses associated with a risk, often when the cost of insuring against the risk would be greater over time than the total losses sustained
  • Self-insurance setting aside funds to cover potential losses rather than purchasing insurance from a third party
• Risk avoidance the decision to avoid or eliminate exposure to a risk altogether, often by relocating from hazard-prone areas or avoiding high-risk activities
• Risk management strategies are most effective when tailored to the specific hazards, vulnerabilities, and capacities of a community or region

Early Warning Systems and Preparedness

• Early warning system an integrated system of hazard monitoring, forecasting, and prediction; disaster risk assessment; communication and preparedness activities; and response capacities
  • Hazard monitoring the continuous observation and data collection to detect changes in the environment that may indicate an impending hazard event (seismic monitoring, river level monitoring)
  • Forecasting and prediction the use of scientific knowledge and technology to anticipate future hazard events and their potential impacts (weather forecasting, tsunami modeling)
  • Risk communication the exchange of information and warnings about potential hazards and risks among experts, public officials, media, and the public
  • Response capacity the ability of emergency services and the public to respond effectively to warnings and minimize the impacts of hazard events
• Preparedness the knowledge and capacities developed by governments, professional response organizations, communities, and individuals to anticipate, respond to, and recover from the impacts of likely, imminent, or current hazard events
  • Emergency planning the development of plans and procedures to minimize the impacts of hazards and ensure an effective response (evacuation plans, shelter management plans)
  • Training and exercises activities designed to develop and maintain the skills and capabilities needed for effective disaster response (emergency drills, tabletop exercises)
  • Public education and outreach efforts to increase public awareness of hazards and promote individual and community preparedness (hazard maps, educational campaigns)
• Community-based disaster preparedness the process of building local capacities to anticipate, cope with, resist, and recover from disasters, often through participatory risk assessment, planning, and training
• Effective early warning systems and preparedness measures can greatly reduce the impacts of disasters by enabling timely and appropriate responses

Recovery and Resilience Building

• Disaster recovery the restoring or improving of livelihoods and health, as well as economic, physical, social, cultural, and environmental assets, systems, and activities, of a disaster-struck community or society
  • Short-term recovery actions taken immediately after a disaster to restore vital support systems and meet basic human needs (emergency shelter, food, water, medical care)
  • Long-term recovery actions taken after the immediate crisis has passed to restore and improve infrastructure, services, and the economy (rebuilding homes, restoring livelihoods)
• Build Back Better the use of the recovery, rehabilitation, and reconstruction phases after a disaster to increase the resilience of nations and communities through integrating disaster risk reduction measures
  • Improving building codes and standards to ensure that reconstructed buildings and infrastructure are more resilient to future hazards
  • Incorporating hazard mitigation measures into land-use planning and development to reduce future risk
  • Strengthening institutional capacities for disaster risk management at all levels of government
• Resilience the ability of a system, community, or society exposed to hazards to resist, absorb, accommodate, adapt to, transform, and recover from the effects of a hazard in a timely and efficient manner
  • Physical resilience the ability of the built environment to withstand and recover from hazard impacts
  • Social resilience the ability of communities to cope with and adapt to stress and change, often through strong social networks and institutions
  • Economic resilience the ability of economies to minimize losses and recover quickly from disasters, often through diversification and flexibility
• Community-based resilience building the process of strengthening local capacities to anticipate, cope with, and recover from disasters, often through participatory risk assessment, planning, and capacity building
• Recovery and resilience building are essential for breaking the cycle of disaster damage, reconstruction, and repeated damage, and for creating sustainable, hazard-resilient communities.