1. Disaster risk concepts and definitions Flashcards
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.
Capacity and Vulnerability of 4 impact areas: Social
Occupation of unsafe areas. high-density occupation of sites/buildings, lack of mobility, job insecurity, lack of education, poverty, corruption, poor management and leadership, lack of planning and preparedness
What are the 4 categories of resilience and their respective definitions?
Resistance - inherent strength, protection, ability to resist stress
Redundancy - system capacity providing alternative options or substitutions to allow continued functioning when some elements fail
Reliability - ability to operate under a range of conditions, frequency with which hazard protection devices fail
Response and Recovery - speed with which disruption is overcome and functionality/ service restored
Characteristics of resilient communities (7)
- good health
- knowledge and education
- reliable services and robust infrastructure
- diverse livelihood opportunities
- healthy ecosystems
- the ability to organise and make decisions
- access to external assistance
What do disaster databases support?
Humanitarian relief, research on nature and causes of disasters, risk modelling/mapping, development of international policies, and insurance assessments.
What are the 6 areas of potential disaster reporting bias and their respective assumption? (see slides)
Hazard - every hazard is represented
Temporal - losses are comparable over time
Threshold - all losses are counted
Accounting - All types of losses are counted (human, economic, direct, indirect)
Geographic - Losses are comparable within and across different geographical areas
Systematic - Losses are computed uniformly
What is the well-known bias?
Small, frequent disaster are under-reported.
Don’t meet the EM-DAT criteria
Small local events triggered by natural hazards that do not usually require external humanitarian assistance may be greater than that of less numerous official disasters
Why does disaster risk seem to be increasing? (3)
Increase in reporting
Increase in hazards
Increase in exposure and vulnerability
5 Components of the DRM cycle
Disaster impact –> Response and relief –> Recovery: Rehabilitation and reconstruction –> Prevention and mitigation –> preparedness and early warning
Define disaster
A serious disruption of the functioning of a community or a society at any scale due to hazardous events interacting with conditions of exposure, vulnerability and capacity, leading to one or more of the following: human, material, economic and environmental losses and impacts.
Information for risk assessment: Exposure
Inventory of elements exposed to risk:
- Type of element
- Temporal variation
- Number
- Economic value
- Location: spatial overlay of hazard and elements at risk
UK critical national infrastructure (9)
- Finance
- Government
- Communications
- Energy
- Emergency services
- Food
- Health
- Water
- Transport
What are the three main sources of global disaster data?
1) The EM-DAT database
2) Reinsurance company data (they insure insurers)
3) The DesInventar system (on a more local level)
GLIDE number invented in Asia, Global identification number
What do we have to be careful with when using global database data?
- Most countries dont systematically collect data on disaster events and losses
- Most disasters are compound events, creating problems with classification
- Typically only tangible impacts are recorded (fatalities/losses)
- No internationally agreed criteria of what constitutes a disaster
- Disaster reporting sources have vested interests, and socio-political influences may affect the figures reported
EM-DAT criteria (4)
Where does the information come from? (6)
10 or more people reported killed
100 or more people reported affected
Declaration of a state of emergency
Call for international assistance
UN agencies, Governments, NGOs, insurance companies, research institutes and press agencies
EM DAT is the main data source for the UN
What are reinsurance companies interested in?
Economic losses
Extensive vs intensive risks
Extensive risks are from the high frequency events, low-intensity losses typically borne by low-income households etc.
