1. Disaster risk concepts and definitions Flashcards
(40 cards)
Define Hazard
A process, phenomenon or human activity that may cause loss of life, injury or other health impacts, property damage, social and economic disruption or environmental degradation.
Define Exposure
The situation of people, infrastructure, housing, production capacities and other tangible human assets located in hazard-prone areas.
Define Vulnerability
The conditions determined by physical, social, economic and environmental factors or processes which increase the susceptibility of an individual, a community, assets or systems to the impacts of hazards.
Define Disaster Risk
The potential loss of life, injury, or destroyed or damaged assets which could occur to a system, society or a community in a specific time period, determined probabilistically as a function of hazard, exposure, vulnerability and capacity.
Define Disaster Risk Reduction
Aimed at preventing new and reducing existing disaster risk and managing residual risk, all of which contribute to strengthening resilience and therefore to the achievement of sustainable development.
Define Resilience
The ability of a system exposed to hazards to resist, absorb, accommodate, adapt to, transform and recover from the effects of a hazard in a timely and efficient manner, including through the preservation and restoration of its essential basic structures and functions through risk management.
3 risk and disaster components
Hazard: type, location, frequency and magnitude of the event
Exposure: spatial and temporal location of elements at risk with respect to a certain hazard. e.g. earthquakes what time of day is important (are all the kids at school)
Vulnerability: degree of damage expected as the result of exposure to a certain hazard. Inverse of capacity
Risk equation
Risk = f(hazard*exposure*vulnerability) Risk = f(hazard*consequence)
What expresses a disaster scenario?
Disaster = risk > capacity to cope
What is capacity (of a system to cope) a function of?
Physical, socio-economic, environmental, political, institutional factors
Information for risk assessment: Hazard
Temporal probability Type of hazard Timing and duration Spatial extent Intensity
Information for risk assessment: Vulnerability
For each of the elements at risk
Damage as a function of intensity
Disaster Risk Reduction options
1) Reduce hazard (likelihood of occurrence): engineering or structural measures
2) Reduce consequences: reduce exposure (avoidance) through planning controls, early warning and evacuation etc. Reduce vulnerability (damage) through improving building resilience, infrastructure, communities, economy, environment.
3) Transfer or share risk: insure losses
4) Accept remaining risk
What are the 3 classifications or hazard and their sub-types?
Natural - Geological, Biological, Hydrological and Atmospheric
Technological/Man-made - Transport accidents, Hazardous materials, Intentional, Unsafe public buildings and facilities, industrial failures
Context - Environmental degradation, Land pressure, climate change
Define trigger event
Many classes and sub-classes or triggers e.g. natural vs. man-made. often more complex due to secondary hazards and human influences.
Define magnitude and intensity
A measure of the size of the event, or the energy released (e.g. volume/velocity of a water of a flood/landslide, or energy or a seismic event/explosion) and the potential to cause damage.
Define frequency
Hazards are expressed as a probability of occurrence of an event of a certain intensity at a particular location within a specific time period (usually as an annual probability)
Define spatial occurrence
Location and extent
Define temporal scale
Speed of onset and duration
Define hazard intensity
The effects of an event related to the presence of damageable assets or people in the area.
When natural phenomena exceeds a certain intensity threshold it becomes a hazard
Categories used to define the consequences (direct and indirect impacts) - SEE TABLE
1) Human and social
2) Physical (buildings and infrastructure)
3) Economic
4) Environmental and Cultural
Capacity and Vulnerability of 4 impact areas: Environmental
Capacity: Natural environmental resources (land, water, forests, minerals), natural barriers to hazards, biodiversity
Vulnerability: Deforestation, pollution, erosion, loss of natural hazard defences (e.g. mangroves), climate change
Capacity and Vulnerability of 4 impact areas: Economic
Capacities: Economic capital, secure livelihoods, financial reserves, diversified economy and agriculture.
Vulnerabilities: Non-diversified economy, mono-crop agriculture, subsistence economies, indebtedness, relief/welfare dependency
Capacity and Vulnerability of 4 impact areas: Physical
Capacities: Robust and reliable public infrastructure, homes, transport, sanitation, water supply, energy…
Vulnerabilities: Unsafe buildings, infrastructure and critical facilities, rapid urbanisation.
