Deterministic hazard assessment

These various parameters of fault and earthquake behavior can then be used to undertake seismic hazard assessments (SHAs) there are two main types of SHAs, deterministic seismic hazard assessment and probabilistic seismic hazard assessment. 

Deterministic seismic hazard analysis Earthquake geology Earthquake hazard analysis Paleoseismology Probabilistic seismic hazard analysis Seismic hazard analysis Seismic hazard assessment... 

Integrating paleoseismological data in Seismic Hazard Assessment (SHA) is dependent on the type of methodology used, i.e., probabilistic (PSHA) or deterministic seismic hazard assessment (DSHA). 

Paleoseismk Data and Deterministic Seismic Hazard Assessment... 

The environmental concentration of a stressor, either measured or estimated, is compared with an effect concentration such as an LC50 (lethal concentration to kill 50% of individuals in a theoretical population in a set period of time) or no observed effect concentration (NOEC) [31, 32]. These are simple ratios of single exposure and effects values and may be used to express hazard or relative safety. This deterministic method uses point estimates to represent one or more factors in a risk assessment and treats them as if they were fixed and precisely known [33]. The calculation of HQs... 

Two types of responses from exposure to hazardous substances, called stochastic or deterministic,5 are of concern in risk assessment. The two types of responses are distinguished by the characteristic features of the dose-response relationship, i.e., the relationship between the dose of a hazardous substance and the probability (or frequency) of a response. 

Dose-Response Assessment for Chemicals That Cause Deterministic Effects. For hazardous chemicals that cause deterministic effects and exhibit a threshold in the dose-response relationship, the purpose of the dose-response assessment is to identify the dose of a substance below which it is not likely that there will be an adverse response in humans. Establishing dose-response relationships for chemicals that cause deterministic effects has proved to be complex because (1) multiple responses are possible, (2) the dose-response assessment is usually based on data from animal studies, (3) thousands of such chemicals exist, and (4) the availability and quality of data are highly variable. As a consequence, the scientific community has needed to devise and adhere to a number of methods to quantify the most important (low or safe dose) part of the dose-response relationship. 

Dose-response concepts. Dose-response assessment for hazardous chemicals that can cause deterministic effects begins with the toxicology data developed during the hazard identification step described in Section 3.1.4.1.2. In many cases, hazard identification and dose-response assessment occur simultaneously. For each chemical, the critical response (a specific response in a specific organ) is identified in the hazard identification process. Using the available data for the critical response, one of the following is established ... 

Although dose-response assessments for deterministic and stochastic effects are discussed separately in this Report, it should be appreciated that many of the concepts discussed in Section 3.2.1.2 for substances that cause deterministic effects apply to substances that cause stochastic effects as well. The processes of hazard identification, including identification of the critical response, and development of data on dose-response based on studies in humans or animals are common to both types of substances. Based on the dose-response data, a NOAEL or a LOAEL can be established based on the limited ability of any study to detect statistically significant increases in responses in exposed populations compared with controls, even though the dose-response relationship is assumed not to have a threshold. Because of the assumed form of the dose-response relationship, however, NOAEL or LOAEL is not normally used as a point of departure to establish safe levels of exposure to substances causing stochastic effects. This is in contrast to the common practice for substances causing deterministic effects of establishing safe levels of exposure, such as RfDs, based on NOAEL or LOAEL (or the benchmark dose) and the use of safety and uncertainty factors. 

Deterministic Responses. Prevention of deterministic responses is a basic principle of health protection for both radionuclides and hazardous chemicals the goal is to achieve zero probability of such responses. Incidence is the primary measure of deterministic response for any hazardous substance, although prompt fatalities also are of concern at sufficiently high doses. In risk assessments and in establishing deterministic dose limits, no adjustments are made to take into account, for example, the relative severity of different responses with regard to consequent reductions in the quality of life. 

In classifying waste, deterministic responses generally should be of concern only for hazardous chemicals (see Section 3.2.2.1). Therefore, the only important issue for risk assessment is the most appropriate approach to estimating thresholds for induction of responses in humans. The primary concern here is that consistent approaches should be used for all substances that induce deterministic effects. NCRP s recommendation that nominal thresholds in humans should be estimated using the benchmark dose method and a safety factor of 10 or 100, depending on whether the data were obtained in a study in humans or animals (see Section 6.1.2.1), is intended to provide consistency in estimating thresholds for all substances that cause deterministic effects. 

In many respects, the foundations and framework of the proposed risk-based hazardous waste classification system and the recommended approaches to implementation are intended to be neutral in regard to the degree of conservatism in protecting public health. With respect to calculations of risk or dose in the numerator of the risk index, important examples include (1) the recommendation that best estimates (MLEs) of probability coefficients for stochastic responses should be used for all substances that cause stochastic responses in classifying waste, rather than upper bounds (UCLs) as normally used in risk assessments for chemicals that induce stochastic effects, and (2) the recommended approach to estimating threshold doses of substances that induce deterministic effects in humans based on lower confidence limits of benchmark doses obtained from studies in humans or animals. Similarly, NCRP believes that the allowable (negligible or acceptable) risks or doses in the denominator of the risk index should be consistent with values used in health protection of the public in other routine exposure situations. NCRP does not believe that the allowable risks or doses assumed for purposes of waste classification should include margins of safety that are not applied in other situations. 

Systems with a long track record are likely to have established controls in place for managing risk. Whether or not these controls have been formally documented in a risk assessment is in many ways less important. What matters is that over time a body of knowledge has been built up, the behaviour of the system has been characterised and the systan s performance is predictable and deterministic. When this experience is unavailable to us, hazards can remain hidden or uncontrolled with an adverse impact on risk. 

Krinitzsky, E. L. (2003). How to combine deterministic and probabilistic methods for assessing earthquake hazards. Engineering Geology, 70, 157-163. doi 10.1016/S0013-7952(02)00269-7... 

As a part of the (periodic) safety reviews (BMU 1996) of the German nuclear power plants, the protection against external hazards has to be re-assessed. According to the guidance on probabilistic safety reviews (BMU 2005) and following the international state-of-the-art (IAEA 2008) the deterministic assessments have to be supplemented by probabilistic analyses. But up to now, the spectrum of external... 

SESSION II Risk Theory and Risk Analysis for Landslides. [1] Landslide Risk Management concepts and framework and examples (2.5 h) [2] Deterministic and Probabilistic models for slope stability evaluation (2 h) [3] Introduction to modelling of catastrophic landslide events (2 h) [4] Empirical models for travel distance (1.5 h) [5] Application examples of probabilistic methods and semi quantitative methods for landslide hazard zonation (2h) [6] Landslide Frequency Assessment (1.5 h) [7] Different components of vulnerability to landslides. Prevention and long term management of landslides (3.5 h) [8] Case Studies coal waste dump risk assessment, example from motorway in La Reunion Island, Aknes Rock slope in Norway (2 h) [9] Application of QRA to other geotechnical problems Internal erosion of dams, crater lake hazard (1.5 h) [10] Advanced numerical models initiation of landslides, propagation of sediments/climate change effects (3.5 h). 

Where a deterministic approach has been selected for the hazard evaluation or directly for the design basis specification, an estimation of the associated return period should be made, at least to allow a comparison with national standards for the design of industrial facilities. This value should then be assessed in the safety assessment phase, as recommended in Ret [9]. 

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