Random variable
A quantity, the magnitude of which is not exactly fixed, but rather the quantity may assume any of a number of values described by a probability distribution.
Regulatory agency (synonymous with Regulator)
Usually a government ministry, department, office, directorate or other unit of government entrusted by law or administrative act with the responsibility for the general supervision of the safe design, construction and operations of structures or facilities, as well as any entity to which all or part of the executive or operational tasks and functions have been delegated by legal power.
Release
In risk analysis, the rate at which a hazard strikes, which is usually expressed in terms of frequency and return period, or with respect to the trend of cumulative impacts.
Reliability
Likelihood of successful performance of a given project element. Mathematically, Reliability = 1 - Probability of failure. See definitions of probability and failure.
Remote sensing
The observation and/or study of an area, object or phenomenon from an aerial distance, frequently using data collected by satellite.
Residual risk
The remaining level of risk at anytime before, during and after a program of risk mitigation measures has been taken.
Risk
Measure of the probability and severity of an adverse effect to life, health, property, or the environment. Quantitatively, Risk = Hazard Potential Worth of Loss. This can be also expressed as Probability of an adverse event times the consequences if the event occurs.
Risk acceptance
An informed decision to accept the consequences and the likelihood of a particular risk.
Risk analysis
The use of available information to estimate the risk to individuals or populations, property or the environment, from hazards. Risk analyses generally contain the following steps: definition of scope, danger (threat) identification, estimation of probability of occurrence to estimate hazard, evaluation of the vulnerability of the element(s) at risk, consequence identification, and risk estimation. Consistent with the common dictionary definition of analysis, viz. A detailed examination of anything complex made in order to understand its nature or to determine its essential features, risk analysis involves the desegregation or decomposition of the system and sources of risk into their fundamental parts. Qualitative risk analysis is the analysis which uses word form, descriptive or numeric rating scales to describe the magnitude of potential consequences and the likelihood that those consequences will occur. Quantitative risk analysis is the analysis based on numerical values of the probability, vulnerability and consequences, and resulting in a numerical value of the risk.
Risk assessment :
The process of making a decision recommendation on whether existing risks are tolerable and present risk control measures are adequate, and if not, whether alternative risk control measures are justified or will be implemented. Risk assessment incorporates the risk analysis and risk evaluation phases.
Risk avoidance
An informed decision not to become involved in a risk situation.
Risk communication
The communications of information about particular risks to the public (individuals, groups, organizations, institutions) and monitoring of the public s response.
Risk control
The implementation and enforcement of actions to control risk, and the periodic re-evaluation of the effectiveness of these actions.
Risk engineering
The application of engineering principles and methods to risk management.
Risk estimation
following steps: frequency analysis, consequence analysis and their integration.
Risk evaluation
The stage at which values and judgement enter the decision process, explicitly or implicitly, by including consideration of the importance of the estimated risks and the associated social, environmental, and economic consequences, in order to identify a range of alternatives for managing the risks.
Risk financing
The methods applied to fund risk treatment and the financial consequences of risk.
Risk governance
The process by which the risk information is collected, analysed and communicated to the stakeholders in order for them to take a decision. Once all the different alternatives have been considered and the existing risk is confronted according to the risk acceptance criteria (either quantitative or qualitative), the management decisions will be taken.
Risk identification
The process of determining what can happen, why and how.
Risk level
The level of risk calculated as a function of likelihood and consequences.
Risk management
The systematic application of management policies, procedures and practices to the tasks of identifying, analysing, assessing, mitigating and monitoring risk.
Risk mitigation
A selective application of appropriate techniques and management principles to reduce either likelihood of an occurrence or its adverse consequences, or both.
Risk perception
Intuitive understanding of risk based on an individual’s own experience and judgement.
Risk reduction (long-term)
Long-term measures to reduce the scale and/or the duration eventual adverse effects of unavoidable or unpreventable disaster hazards on a society which is at risk, by reducing the vulnerability of its people, structures, services, and economic activities to the impact of known disaster hazards. Typical risk reduction measures include improved building standards, flood plain zoning and landuse planning, crop diversification, and planting windbreaks. The measures are frequently subdivided into structural and non-structural, active and passive measures.
Risk retention
Intentionally or unintentionally retaining the responsibility for loss or financial burden of loss within the organization.
Risk tolerance
A decision on the level of the tolerable residual risk after protection measures have been implemented.
Risk transfer
Shifting the responsibility or burden for loss to another party through legislation, contract, insurance or other means. Risk transfer can also refer to shifting a physical risk or part thereof elsewhere.
Risk treatment
Selection and implementation of appropriate options for dealing with risk.
Risk-based decision-making
Decision-making, which has as a main input the results of risk assessment. It involves a balancing of social and other benefits and the residual risks.
Risk-benefit analysis
In terms of disasters, the benefits of inhabiting areas at risk, of carrying out various activities in them and of putting oneself at risk, set off against the cost of damage and losses in disaster (including estimated future costs of the event) and of mitigation works.
Rock fall
A free movement of rocky material away from steep slopes such as cliffs. The materials are usually described as moving en masse. The detachment of a part of the bedrock and subsequent fall form the slope is followed by impact with the slope below when secondary processes take place. The detachment process may take time and it arises from internal or external factors that are often combined.
Rock slide
A downward, usually sudden and rapid movement of newly detached segments of bedrock over an inclined surface or over pre-existing features.
Rupture zone
Area representing the parting of displaced mass from the in situ slope.
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