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Sample records for seismic margin assessment

  1. Assessment of seismic margin calculation methods

    International Nuclear Information System (INIS)

    Kennedy, R.P.; Murray, R.C.; Ravindra, M.K.; Reed, J.W.; Stevenson, J.D.

    1989-03-01

    Seismic margin review of nuclear power plants requires that the High Confidence of Low Probability of Failure (HCLPF) capacity be calculated for certain components. The candidate methods for calculating the HCLPF capacity as recommended by the Expert Panel on Quantification of Seismic Margins are the Conservative Deterministic Failure Margin (CDFM) method and the Fragility Analysis (FA) method. The present study evaluated these two methods using some representative components in order to provide further guidance in conducting seismic margin reviews. It is concluded that either of the two methods could be used for calculating HCLPF capacities. 21 refs., 9 figs., 6 tabs

  2. Seismic and tsunami safety margin assessment

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    Nuclear Regulation Authority is going to establish new seismic and tsunami safety guidelines to increase the safety of NPPs. The main purpose of this research is testing structures/components important to safety and tsunami resistant structures/components, and evaluating the capacity of them against earthquake and tsunami. Those capacity data will be utilized for the seismic and tsunami back-fit review based on the new seismic and tsunami safety guidelines. The summary of the program in 2012 is as follows. 1. Component seismic capacity test and quantitative seismic capacity evaluation. PWR emergency diesel generator partial-model seismic capacity tests have been conducted and quantitative seismic capacities have been evaluated. 2. Seismic capacity evaluation of switching-station electric equipment. Existing seismic test data investigation, specification survey and seismic response analyses have been conducted. 3. Tsunami capacity evaluation of anti-inundation measure facilities. Tsunami pressure test have been conducted utilizing a small breakwater model and evaluated basic characteristics of tsunami pressure against seawall structure. (author)

  3. Seismic and tsunami safety margin assessment

    International Nuclear Information System (INIS)

    2013-01-01

    Nuclear Regulation Authority is going to establish new seismic and tsunami safety guidelines to increase the safety of NPPs. The main purpose of this research is testing structures/components important to safety and tsunami resistant structures/components, and evaluating the capacity of them against earthquake and tsunami. Those capacity data will be utilized for the seismic and tsunami back-fit review based on the new seismic and tsunami safety guidelines. The summary of the program in 2012 is as follows. 1. Component seismic capacity test and quantitative seismic capacity evaluation. PWR emergency diesel generator partial-model seismic capacity tests have been conducted and quantitative seismic capacities have been evaluated. 2. Seismic capacity evaluation of switching-station electric equipment. Existing seismic test data investigation, specification survey and seismic response analyses have been conducted. 3. Tsunami capacity evaluation of anti-inundation measure facilities. Tsunami pressure test have been conducted utilizing a small breakwater model and evaluated basic characteristics of tsunami pressure against seawall structure. (author)

  4. Comparison of seismic margin assessment and probabilistic risk assessment in seismic IPE

    International Nuclear Information System (INIS)

    Reed, J.W.; Kassawara, R.P.

    1993-01-01

    A comparison of technical requirements and managerial issues between seismic margin assessment (SMA) and seismic probabilistic risk assessment (SPRA) in a seismic Individual Plant Examination (IPE) is presented and related to requirements for an Unresolved Safety Issue (USI) A-46 review which is required for older nuclear power plants. Advantages and disadvantages are discussed for each approach. Technical requirements reviewed for a seismic IPE include: scope of plants covered, seismic input, scope of review, selection of equipment, required experience and training of engineers, walkdown procedure, evaluation of components, relay review, containment review, quality assurance, products, documentation requirements, and closure procedure. Managerial issues discussed include regulatory acceptability, compatibility with seismic IPE, compliance with seismic IPE requirements, ease of use by utilities, and relative cost

  5. An assessment of seismic margins in nuclear plant piping

    International Nuclear Information System (INIS)

    Chen, W.P.; Jaquay, K.R.; Chokshi, N.C.; Terao, D.

    1995-01-01

    Interim results of an ongoing program to assist the U.S. Nuclear Regulatory Commission (NRC) in developing regulatory positions on the seismic analyses of piping and overall safety margins of piping systems are reported. Results of reviews of previous seismic testing, primarily the Electric Power Research Institute (EPRI)/NRC Piping and Fitting Dynamic Reliability Program, and assessments of the ASME Code, Section III, piping seismic design criteria as revised by the 1994 Addenda are reported. Major issues are identified herein only. Technical details are to be provided elsewhere. (author). 4 refs., 2 figs

  6. Seismic safety margin assessment program (Annual safety research report, JFY 2010)

    International Nuclear Information System (INIS)

    Suzuki, Kenichi; Iijima, Toru; Inagaki, Masakatsu; Taoka, Hideto; Hidaka, Shinjiro

    2011-01-01

    Seismic capacity test data, analysis method and evaluation code provided by Seismic Safety Margin Assessment Program have been utilized for the support of seismic back-check evaluation of existing plants. The summary of the program in 2010 is as follows. 1. Component seismic capacity test and quantitative seismic capacity evaluation. Many seismic capacity tests of various snubbers were conducted and quantitative seismic capacities were evaluated. One of the emergency diesel generator partial-model seismic capacity tests was conducted and quantitative seismic capacity was evaluated. Some of the analytical evaluations of piping-system seismic capacities were conducted. 2. Analysis method for minute evaluation of component seismic response. The difference of seismic response of large components such as primary containment vessel and reactor pressure vessel when they were coupled with 3-dimensional FEM building model or 1-dimensional lumped mass building model, was quantitatively evaluated. 3. Evaluation code for quantitative evaluation of seismic safety margin of systems, structures and components. As the example, quantitative evaluation of seismic safety margin of systems, structures and components were conducted for the reference plant. (author)

  7. Pickering seismic safety margin

    International Nuclear Information System (INIS)

    Ghobarah, A.; Heidebrecht, A.C.; Tso, W.K.

    1992-06-01

    A study was conducted to recommend a methodology for the seismic safety margin review of existing Canadian CANDU nuclear generating stations such as Pickering A. The purpose of the seismic safety margin review is to determine whether the nuclear plant has sufficient seismic safety margin over its design basis to assure plant safety. In this review process, it is possible to identify the weak links which might limit the seismic performance of critical structures, systems and components. The proposed methodology is a modification the EPRI (Electric Power Research Institute) approach. The methodology includes: the characterization of the site margin earthquake, the definition of the performance criteria for the elements of a success path, and the determination of the seismic withstand capacity. It is proposed that the margin earthquake be established on the basis of using historical records and the regional seismo-tectonic and site specific evaluations. The ability of the components and systems to withstand the margin earthquake is determined by database comparisons, inspection, analysis or testing. An implementation plan for the application of the methodology to the Pickering A NGS is prepared

  8. Seismic margin assessment and earthquake experience based methods for WWER-440/213 type NPPs

    International Nuclear Information System (INIS)

    Masopust, R.

    1996-01-01

    This report covers the review of the already completed studies, namely, safe shutdown system identification and classification for Bohunice NPP and the comparative study of standards and criteria. It contains a report on currently ongoing studies concerning seismic margin assessment and earthquake experience based methods in application for seismic evaluation and verification of structures and equipment components of the operating WWER-440/213 type NPPs. This is based on experiences obtained from Paks NPP. The work plan for the remaining period of Benchmark CRP and the new proposals are included. These are concerned with seismic evaluation of selected safety related mechanical equipment and pipes of Paks NPP, and the actual seismic issues of the Temelin WWER-1000 type NPP

  9. Seismic margin assessment of spanish nuclear power plants: a perspective from industry and regulators

    International Nuclear Information System (INIS)

    Garcia-Monge, Juan; Beltran, Francisco; Sanchez-Cabanero, Jose G.

    2001-01-01

    The worldwide experience with probabilistic safety analysis (PSA) of nuclear power plants shows that the risk derived from earthquakes can be a significant contributor to core damage frequency in some instances. As a consequence, no severe accident safety assessment can be considered complete without giving, due consideration to seismic risk. This fact has been recognized by some regulators. in particular, by the U.S. Nuclear Regulatory Commission (NRC), who has included seismic risk assessment in its severe accident policy. The NRC severe accident policy was adopted by the Spanish nuclear regulator. the Consejo de Seguridad Nuclear (CSN). As a result. all plants in Spain were asked to perform a seismic risk analysis according to Supplements No. 4 and 5 of Generic Letter 88-20 and NUREG-1407, which included the containment failure analysis. At present in Spain there arc nine operating reactors at seven sites: six Westinghouse-PWR, two GE-BWR and one Siemens/KW U-PWR. The vintages are very different: the oldest plant started commercial operation in 1968 and the most recent, in 1988. In this framework, the Spanish Owners Group (SOG) proposed to CSN in 1994 to carry out the seismic risk analysis of the plants using seismic margin methodologies. This kind of methods requires, as a starting point, the definition of a seismic margin earthquake (SNIE), also called review level earthquake (RLL). For this purpose, tile SOG sponsored a general Probabilistic Seismic Hazard Analysis (PSHA) for the seven Spanish sites. The results of this PSHA were used by the SOG to define tile RLE and the scope of the study for each plant (binning of plants). The proposal was submitted to the CSN for evaluation. The CSN evaluation was based on the NRC practical experience and was helped by the technical advise of US Lawrence Livermore National Laboratory. The review showed that the uncertainties on seismic hazard had not been fully captured and that it would have been justified to consider a

  10. Use of response envelopes for seismic margin assessment of reinforced concrete walls and slabs

    Energy Technology Data Exchange (ETDEWEB)

    Ile, Nicolas; Frau, Alberto, E-mail: alberto.frau@cea.fr

    2017-04-01

    Highlights: • Proposal of a method for application of the elliptical envelope to RC shell elements. • Proposal of new algorithms for the seismic margin evaluation for RC shell elements. • Verification of a RC wall 3D structure, using the proposed assessment approach. - Abstract: Seismic safety evaluations of existing nuclear facilities are usually based on the assumption of structural linearity. For the design basis earthquake (DBE), it is reasonable to apply a conventional evaluation of the seismic safety of building structures and carry out a linear elastic analysis to assess the load effects on structural elements. Estimating the seismic capacity of a structural element requires an estimation of the critical combination of responses acting in this structural element and compare this combination with the capacity of the element. By exploiting the response-spectrum-based procedure for predicting the response envelopes in linear structures formulated by Menun and Der Kiureghian (2000a), algorithms are developed for the seismic margin assessment of reinforced concrete shell finite elements. These algorithms facilitate the comparison of the response-spectrum-based envelopes to prescribed capacity surfaces for the purpose of assessing the safety margin of this kind of structures. The practical application of elliptical response envelopes in case of shell finite elements is based on the use of layer models such as those developed by Marti (1990), which transfer the generalized stress field to three layers under the assumption that the two outer layers carry membrane forces and the internal layer carries only the out-of-plane shears. The utility of the assessment approach is discussed with reference to a case study of a 3D structure made of reinforced concrete walls.

  11. Use of response envelopes for seismic margin assessment of reinforced concrete walls and slabs

    International Nuclear Information System (INIS)

    Ile, Nicolas; Frau, Alberto

    2017-01-01

    Highlights: • Proposal of a method for application of the elliptical envelope to RC shell elements. • Proposal of new algorithms for the seismic margin evaluation for RC shell elements. • Verification of a RC wall 3D structure, using the proposed assessment approach. - Abstract: Seismic safety evaluations of existing nuclear facilities are usually based on the assumption of structural linearity. For the design basis earthquake (DBE), it is reasonable to apply a conventional evaluation of the seismic safety of building structures and carry out a linear elastic analysis to assess the load effects on structural elements. Estimating the seismic capacity of a structural element requires an estimation of the critical combination of responses acting in this structural element and compare this combination with the capacity of the element. By exploiting the response-spectrum-based procedure for predicting the response envelopes in linear structures formulated by Menun and Der Kiureghian (2000a), algorithms are developed for the seismic margin assessment of reinforced concrete shell finite elements. These algorithms facilitate the comparison of the response-spectrum-based envelopes to prescribed capacity surfaces for the purpose of assessing the safety margin of this kind of structures. The practical application of elliptical response envelopes in case of shell finite elements is based on the use of layer models such as those developed by Marti (1990), which transfer the generalized stress field to three layers under the assumption that the two outer layers carry membrane forces and the internal layer carries only the out-of-plane shears. The utility of the assessment approach is discussed with reference to a case study of a 3D structure made of reinforced concrete walls.

  12. Seismic Margin Assessment for Research Reactor using Fragility based Fault Tree Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kwag, Shinyoung; Oh, Jinho; Lee, Jong-Min; Ryu, Jeong-Soo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    The research reactor has been often subjected to external hazards during the design lifetime. Especially, a seismic event can be one of significant threats to the failure of structure system of the research reactor. This failure is possibly extended to the direct core damage of the reactor. For this purpose, the fault tree for structural system failure leading to the core damage under an earthquake accident is developed. The failure probabilities of basic events are evaluated as fragility curves of log-normal distributions. Finally, the plant-level seismic margin is investigated by the fault tree analysis combining with fragility data and the critical path is identified. The plant-level probabilistic seismic margin assessment using the fragility based fault tree analysis was performed for quantifying the safety of research reactor to a seismic hazard. For this, the fault tree for structural system failure leading to the core damage of the reactor under a seismic accident was developed. The failure probabilities of basic events were evaluated as fragility curves of log-normal distributions.

  13. NRC Seismic Design Margins Program Plan

    International Nuclear Information System (INIS)

    Cummings, G.E.; Johnson, J.J.; Budnitz, R.J.

    1985-08-01

    Recent studies estimate that seismically induced core melt comes mainly from earthquakes in the peak ground acceleration range from 2 to 4 times the safe shutdown earthquake (SSE) acceleration used in plant design. However, from the licensing perspective of the US Nuclear Regulatory Commission, there is a continuing need for consideration of the inherent quantitative seismic margins because of, among other things, the changing perceptions of the seismic hazard. This paper discusses a Seismic Design Margins Program Plan, developed under the auspices of the US NRC, that provides the technical basis for assessing the significance of design margins in terms of overall plant safety. The Plan will also identify potential weaknesses that might have to be addressed, and will recommend technical methods for assessing margins at existing plants. For the purposes of this program, a general definition of seismic design margin is expressed in terms of how much larger that the design basis earthquake an earthquake must be to compromise plant safety. In this context, margin needs to be determined at the plant, system/function, structure, and component levels. 14 refs., 1 fig

  14. Systems considerations in seismic margin evaluations

    International Nuclear Information System (INIS)

    Buttermer, D.R.

    1987-01-01

    Increasing knowledge in the geoscience field has led to the understanding that, although highly unlikely, it is possible for a nuclear power plant to be subjected to earthquake ground motion greater than that for which the plant was designed. While it is recognized that there are conservatisms inherent in current design practices, interest has developed in evaluating the seismic risk of operating plants. Several plant-specific seismic probabilistic risk assessments (SPRA) have been completed to address questions related to the seismic risk of a plant. The results from such SPRAs are quite informative, but such studies may entail a considerable amount of expensive analysis of large portions of the plant. As an alternative to an SPRA, it may be more practical to select an earthquake level above the design basis for which plant survivability is to be demonstrated. The principal question to be addressed in a seismic margin evaluation is: At what ground motion levels does one have a high confidence that the probability of seismically induced core damage is sufficiently low? In a seismic margin evaluation, an earthquake level is selected (based on site-specific geoscience considerations) for which a stable, long-term safe shutdown condition is to be demonstrated. This prespecified earthquake level is commonly referred to as the seismic margin earthquake (SME). The Electric Power Research Institute is currently supporting a research project to develop procedures for use by the utilities to allow them to perform nuclear plant seismic margin evaluations. This paper describes the systems-related aspects of these procedures

  15. Seismic margins and calibration of piping systems

    International Nuclear Information System (INIS)

    Shieh, L.C.; Tsai, N.C.; Yang, M.S.; Wong, W.L.

    1985-01-01

    The Seismic Safety Margins Research Program (SSMRP) is a US Nuclear Regulatory Commission-funded, multiyear program conducted by Lawrence Livermore National Laboratory (LLNL). Its objective is to develop a complete, fully coupled analysis procedure for estimating the risk of earthquake-induced radioactive release from a commercial nuclear power plant and to determine major contributors to the state-of-the-art seismic and systems analysis process and explicitly includes the uncertainties in such a process. The results will be used to improve seismic licensing requirements for nuclear power plants. In Phase I of SSMRP, the overall seismic risk assessment methodology was developed and assembled. The application of this methodology to the seismic PRA (Probabilistic Risk Assessment) at the Zion Nuclear Power Plant has been documented. This report documents the method deriving response factors. The response factors, which relate design calculated responses to best estimate values, were used in the seismic response determination of piping systems for a simplified seismic probablistic risk assessment. 13 references, 31 figures, 25 tables

  16. Study on structural seismic margin and probabilistic seismic risk. Development of a structural capacity-seismic risk diagram

    International Nuclear Information System (INIS)

    Nakajima, Masato; Ohtori, Yasuki; Hirata, Kazuta

    2010-01-01

    Seismic margin is extremely important index and information when we evaluate and account seismic safety of critical structures, systems and components quantitatively. Therefore, it is required that electric power companies evaluate the seismic margin of each plant in back-check of nuclear power plants in Japan. The seismic margin of structures is usually defined as a structural capacity margin corresponding to design earthquake ground motion. However, there is little agreement as to the definition of the seismic margin and we have no knowledge about a relationship between the seismic margin and seismic risk (annual failure probability) which is obtained in PSA (Probabilistic Safety Assessment). The purpose of this report is to discuss a definition of structural seismic margin and to develop a diagram which can identify a relation between seismic margin and seismic risk. The main results of this paper are described as follows: (1) We develop seismic margin which is defined based on the fact that intensity of earthquake ground motion is more appropriate than the conventional definition (i.e., the response-based seismic margin) for the following reasons: -seismic margin based on earthquake ground motion is invariant where different typed structures are considered, -stakeholders can understand the seismic margin based on the earthquake ground motion better than the response-based one. (2) The developed seismic margin-risk diagram facilitates us to judge easily whether we need to perform detailed probabilistic risk analysis or only deterministic analysis, given that the reference risk level although information on the uncertainty parameter beta is not obtained. (3) We have performed numerical simulations based on the developed method for four sites in Japan. The structural capacity-risk diagram differs depending on each location because the diagram is greatly influenced by seismic hazard information for a target site. Furthermore, the required structural capacity

  17. Seismic margin analysis technique for nuclear power plant structures

    International Nuclear Information System (INIS)

    Seo, Jeong Moon; Choi, In Kil

    2001-04-01

    In general, the Seismic Probabilistic Risk Assessment (SPRA) and the Seismic Margin Assessment(SAM) are used for the evaluation of realistic seismic capacity of nuclear power plant structures. Seismic PRA is a systematic process to evaluate the seismic safety of nuclear power plant. In our country, SPRA has been used to perform the probabilistic safety assessment for the earthquake event. SMA is a simple and cost effective manner to quantify the seismic margin of individual structural elements. This study was performed to improve the reliability of SMA results and to confirm the assessment procedure. To achieve this goal, review for the current status of the techniques and procedures was performed. Two methodologies, CDFM (Conservative Deterministic Failure Margin) sponsored by NRC and FA (Fragility Analysis) sponsored by EPRI, were developed for the seismic margin review of NPP structures. FA method was originally developed for Seismic PRA. CDFM approach is more amenable to use by experienced design engineers including utility staff design engineers. In this study, detailed review on the procedures of CDFM and FA methodology was performed

  18. Establishing seismic design criteria to achieve an acceptable seismic margin

    International Nuclear Information System (INIS)

    Kennedy, R.P.

    1997-01-01

    In order to develop a risk based seismic design criteria the following four issues must be addressed: (1) What target annual probability of seismic induced unacceptable performance is acceptable? (2). What minimum seismic margin is acceptable? (3) Given the decisions made under Issues 1 and 2, at what annual frequency of exceedance should the Safe Shutdown Earthquake ground motion be defined? (4) What seismic design criteria should be established to reasonably achieve the seismic margin defined under Issue 2? The first issue is purely a policy decision and is not addressed in this paper. Each of the other three issues are addressed. Issues 2 and 3 are integrally tied together so that a very large number of possible combinations of responses to these two issues can be used to achieve the target goal defined under Issue 1. Section 2 lays out a combined approach to these two issues and presents three potentially attractive combined resolutions of these two issues which reasonably achieves the target goal. The remainder of the paper discusses an approach which can be used to develop seismic design criteria aimed at achieving the desired seismic margin defined in resolution of Issue 2. Suggestions for revising existing seismic design criteria to more consistently achieve the desired seismic margin are presented

  19. Overview of seismic margin insights gained from seismic PRA results

    International Nuclear Information System (INIS)

    Kennedy, R.P.; Sues, R.H.; Campbell, R.D.

    1986-01-01

    This paper presents the findings of a study conducted under NRC and EPRI sponsorship in which published seismic PRAs were reviewed in order to gain insight to the seismic margins inherent in existing nuclear plants. The approach taken was to examine the fragilities of those components which have been found to be dominant contributors to seismic risk at plants in low-to-moderate seismic regions (SSE levels between 0.12g and 0.25g). It is concluded that there is significant margin inherent in the capacity of most critical components above the plant design basis. For ground motions less than about 0.3g, the predominant sources of seismic risk are loss of offsite power coupled with random failure of the emergency diesels, non-recoverable circuit breaker trip due to relay chatter, unanchored equipment, unreinforced non-load bearing block walls, vertical water storage tanks, systems interactions and possibly soil liquefaction. Recommendations as to which components should be reviewed in seismic margin studies for margin earthquakes less than 0.3g, between 0.3g and 0.5g, and greater than 0.5g, developed by the NRC expert panel on the quantification of seismic margins (based on the review of past PRA data, earthquake experience data, and their own personal experience) are presented

  20. Seismic safety margins research program overview

    International Nuclear Information System (INIS)

    Tokarz, F.J.; Smith, P.D.

    1978-01-01

    A multiyear seismic research program has been initiated at the Lawrence Livermore Laboratory. This program, the Seismic Safety Margins Research Program (SSMRP) is funded by the U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research. The program is designed to develop a probabilistic systems methodology for determining the seismic safety margins of nuclear power plants. Phase I, extending some 22 months, began in July 1978 at a funding level of approximately $4.3 million. Here we present an overview of the SSMRP. Included are discussions on the program objective, the approach to meet the program goal and objectives, end products, the probabilistic systems methodology, and planned activities for Phase I

  1. Seismic Margin of 500MWe PFBR Beyond Safe Shutdown Earthquake

    International Nuclear Information System (INIS)

    Sajish, S.D.; Chellapandi, P.; Chetal, S.C.

    2012-01-01

    Summary: • Seismic design aspects of safety related systems and components of PFBR is discussed with a focus on reactor assembly components. • PFBR is situated in a low seismic area with a peak ground acceleration value of 0.156 g. • The design basis ground motion parameters for the seismic design are evaluated by deterministic method and confirmed by probabilistic seismic hazard analysis. • Review of the seismic design of various safety related systems and components indicate that margin is available to meet any demand due to an earthquake beyond SSE. • Reactor assembly vessels are the most critical components w.r.t seismic loading. • Minimum safety margin is 1.41 for plastic deformation and 1.46 against buckling. • From the preliminary investigation we come to the conclusion that PFBR can withstand an earthquake up to 0.22 g without violating any safety limits. • Additional margin can be estimated by detailed fragility analysis and seismic margin assessment methods

  2. Risk insights from seismic margin reviews

    International Nuclear Information System (INIS)

    Budnitz, R.J.

    1990-01-01

    This paper discusses the information that has been derived from the three seismic-margin reviews conducted so far, and the information that is potentially available from using the seismic-margin method more generally. There are two different methodologies for conducting seismic margin reviews of nuclear power plants, one developed under NRC sponsorship and one developed under sponsorship of the Electric Power Research Institute. Both methodologies will be covered in this paper. The paper begins with a summary of the steps necessary to complete a margin review, and will then outline the key technical difficulties that need to be addressed. After this introduction, the paper covers the safety and operational insights derived from the three seismic-margin reviews already completed: the NRC-sponsored review at Maine Yankee; the EPRI-sponsored review at Catawba; and the joint EPRI/NRC/utility effort at Hatch. The emphasis is on engineering insights, with attention to the aspects of the reviews that are easiest to perform and that provide the most readily available insights

  3. A quantitative evaluation of seismic margin of typical sodium piping

    International Nuclear Information System (INIS)

    Morishita, Masaki

    1999-05-01

    It is widely recognized that the current seismic design methods for piping involve a large amount of safety margin. From this viewpoint, a series of seismic analyses and evaluations with various design codes were made on typical LMFBR main sodium piping systems. Actual capability against seismic loads were also estimated on the piping systems. Margins contained in the current codes were quantified based on these results, and potential benefits and impacts to the piping seismic design were assessed on possible mitigation of the current code allowables. From the study, the following points were clarified; 1) A combination of inelastic time history analysis and true (without margin)strength capability allows several to twenty times as large seismic load compared with the allowable load with the current methods. 2) The new rule of the ASME is relatively compatible with the results of inelastic analysis evaluation. Hence, this new rule might be a goal for the mitigation of seismic design rule. 3) With this mitigation, seismic design accommodation such as equipping with a large number of seismic supports may become unnecessary. (author)

  4. The Seismicity of Two Hyperextended Margins

    Science.gov (United States)

    Redfield, Tim; Terje Osmundsen, Per

    2013-04-01

    A seismic belt marks the outermost edge of Scandinavia's proximal margin, inboard of and roughly parallel to the Taper Break. A similar near- to onshore seismic belt runs along its inner edge, roughly parallel to and outboard of the asymmetric, seaward-facing escarpment. The belts converge at both the northern and southern ends of Scandinavia, where crustal taper is sharp and the proximal margin is narrow. Very few seismic events have been recorded on the intervening, gently-tapering Trøndelag Platform. Norway's distribution of seismicity is systematically ordered with respect to 1) the structural templates of high-beta extension that shaped the thinning gradient during Late Jurassic or Early Cretaceous time, and 2) the topographically resurgent Cretaceous-Cenozoic "accommodation phase" family of escarpments that approximate the innermost limit of crustal thinning [See Redfield and Osmundsen (2012) for diagrams, definitions, discussion, and supporting citations.] Landwards from the belt of earthquake epicenters that mark the Taper Break the crust consistently thickens, and large fault arrays tend to sole out at mid crustal levels. Towards the sea the crystalline continental crust is hyperextended, pervasively faulted, and generally very thin. Also, faulting and serpentinization may have affected the uppermost parts of the distal margin's lithospheric mantle. Such contrasting structural conditions may generate a contrasting stiffness: for a given stress, more strain can be accommodated in the distal margin than in the less faulted proximal margin. By way of comparison, inboard of the Taper Break on the gently-tapered Trøndelag Platform, faulting was not penetrative. There, similar structural conditions prevail and proximal margin seismicity is negligible. Because stress concentration can occur where material properties undergo significant contrast, the necking zone may constitute a natural localization point for post-thinning phase earthquakes. In Scandinavia

  5. Seismic margin review of the Maine Yankee Atomic Power Station: Fragility analysis

    International Nuclear Information System (INIS)

    Ravindra, M.K.; Hardy, G.S.; Hashimoto, P.S.; Griffin, M.J.

    1987-03-01

    This Fragility Analysis is the third of three volumes for the Seismic Margin Review of the Maine Yankee Atomic Power Station. Volume 1 is the Summary Report of the first trial seismic margin review. Volume 2, Systems Analysis, documents the results of the systems screening for the review. The three volumes are part of the Seismic Margins Program initiated in 1984 by the Nuclear Regulatory Commission (NRC) to quantify seismic margins at nuclear power plants. The overall objectives of the trial review are to assess the seismic margins of a particular pressurized water reactor, and to test the adequacy of this review approach, quantification techniques, and guidelines for performing the review. Results from the trial review will be used to revise the seismic margin methodology and guidelines so that the NRC and industry can readily apply them to assess the inherent quantitative seismic capacity of nuclear power plants

  6. Seismic margin review of the Maine Yankee Atomic Power Station: Fragility analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ravindra, M. K.; Hardy, G. S.; Hashimoto, P. S.; Griffin, M. J.

    1987-03-01

    This Fragility Analysis is the third of three volumes for the Seismic Margin Review of the Maine Yankee Atomic Power Station. Volume 1 is the Summary Report of the first trial seismic margin review. Volume 2, Systems Analysis, documents the results of the systems screening for the review. The three volumes are part of the Seismic Margins Program initiated in 1984 by the Nuclear Regulatory Commission (NRC) to quantify seismic margins at nuclear power plants. The overall objectives of the trial review are to assess the seismic margins of a particular pressurized water reactor, and to test the adequacy of this review approach, quantification techniques, and guidelines for performing the review. Results from the trial review will be used to revise the seismic margin methodology and guidelines so that the NRC and industry can readily apply them to assess the inherent quantitative seismic capacity of nuclear power plants.

  7. Seismic safety margins research program. Phase I final report - Overview

    International Nuclear Information System (INIS)

    Smith, P.D.; Dong, R.G.; Bernreuter, D.L.; Bohn, M.P.; Chuang, T.Y.; Cummings, G.E.; Johnson, J.J.; Mensing, R.W.; Wells, J.E.

    1981-04-01

    The Seismic Safety Margins Research Program (SSMRP) is a multiyear, multiphase program whose overall objective is to develop improved methods for seismic safety assessments of nuclear power plants, using a probabilistic computational procedure. The program is being carried out at the Lawrence Livermore National Laboratory and is sponsored by the U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research. Phase I of the SSMRP was successfully completed in January 1981: A probabilistic computational procedure for the seismic risk assessment of nuclear power plants has been developed and demonstrated. The methodology is implemented by three computer programs: HAZARD, which assesses the seismic hazard at a given site, SMACS, which computes in-structure and subsystem seismic responses, and SEISIM, which calculates system failure probabilities and radioactive release probabilities, given (1) the response results of SMACS, (2) a set of event trees, (3) a family of fault trees, (4) a set of structural and component fragility descriptions, and (5) a curve describing the local seismic hazard. The practicality of this methodology was demonstrated by computing preliminary release probabilities for Unit 1 of the Zion Nuclear Power Plant north of Chicago, Illinois. Studies have begun aimed at quantifying the sources of uncertainty in these computations. Numerous side studies were undertaken to examine modeling alternatives, sources of error, and available analysis techniques. Extensive sets of data were amassed and evaluated as part of projects to establish seismic input parameters and to produce the fragility curves. (author)

  8. Seismic Safety Margins Research Program: a concluding look

    International Nuclear Information System (INIS)

    Cummings, G.E.

    1984-01-01

    The Seismic Safety Margins Research Program (SSMRP) was started in 1978 with the goal of developing tools and data bases to compute the probability of earthquake - caused radioactive release from commercial nuclear power plants. These tools and data bases were to help NRC to assess seismic safety at nuclear plants. The methodology to be used was finalized in 1982 and applied to the Zion Nuclear Power Station. The SSMRP will be completed this year with the development of a more simplified method of analysis and a demonstration of its use on Zion. This simplified method is also being applied to a boiling-water-reactor, LaSalle

  9. Seismic margin reviews of nuclear power plants: Identification of important functions and systems

    International Nuclear Information System (INIS)

    Prassinos, P.G.; Moore, D.L.; Amico, P.J.

    1987-01-01

    The results from the review of the seven utility-sponsored seismic PRAs plus the Zion SSMRP have been used to develop some insights regarding the importance of various systems and functions to seismic margins. By taking this information and combining it with the fragility insights we can develop some functional/systemic screening guideline for margin studies. This screening approach will greatly reduce the scope of the analysis. It is possible only to come to conclusions regarding the importance of plant systems and safety functions for PWRs, for which six plants were studied. For PWRs, it is possible to categorize plant safety functions as belonging to one of two groups, one of which is important to the assessment of seismic margins and one of which is not. The important functional group involves only two functions that must be considered for estimating seismic margin. These two functions are shutting down the nuclear reaction and providing cooling to the reactor core in the time period immediately following the seismic event (that is, the injection phase or pre-residual heat removal time period). It is possible to reasonably estimate the seismic margin of the plant by performing a study only involving the analysis of the plant systems and structure which are required in order to perform the two functions. Such analysis must include an assessment of a complete set of seismic initiating events. (orig./HP)

  10. Seismic Safety Margins Research Program (Phase I). Project VII. Systems analysis specification of computational approach

    International Nuclear Information System (INIS)

    Wall, I.B.; Kaul, M.K.; Post, R.I.; Tagart, S.W. Jr.; Vinson, T.J.

    1979-02-01

    An initial specification is presented of a computation approach for a probabilistic risk assessment model for use in the Seismic Safety Margin Research Program. This model encompasses the whole seismic calculational chain from seismic input through soil-structure interaction, transfer functions to the probability of component failure, integration of these failures into a system model and thereby estimate the probability of a release of radioactive material to the environment. It is intended that the primary use of this model will be in sensitivity studies to assess the potential conservatism of different modeling elements in the chain and to provide guidance on priorities for research in seismic design of nuclear power plants

  11. Compilation, assessment and expansion of the strong earthquake ground motion data base. Seismic Safety Margins Research Program (SSMRP)

    International Nuclear Information System (INIS)

    Crouse, C.B.; Hileman, J.A.; Turner, B.E.; Martin, G.R.

    1980-09-01

    A catalog has been prepared which contains information for: (1) world-wide, ground-motion accelerograms (2) the accelerograph sites where these records were obtained, and (3) the seismological parameters of the causative earthquakes. The catalog is limited to data for those accelerograms which have been digitized and published. In addition, the quality and completeness of these data are assessed. This catalog is unique because it is the only publication which contains comprehensive information on the recording conditions of all known digitized accelerograms. However, information for many accelerograms is missing. Although some literature may have been overlooked, most of the missing data has not been published. Nevertheless, the catalog provides a convenient reference and useful tool for earthquake engineering research and applications. (author)

  12. Seismic risk assessment of a BWR

    International Nuclear Information System (INIS)

    Wells, J.E.; Bernreuter, D.L.; Chen, J.C.; Lappa, D.A.; Chuang, T.Y.; Murray, R.C.; Johnson, J.J.

    1987-01-01

    The simplified seismic risk methodology developed in the USNRC Seismic Safety Margins Research Program (SSMRP) was demonstrated by its application to the Zion nuclear power plant (PWR). The simplified seismic risk methodology was developed to reduce the costs associated with a seismic risk analysis while providing adequate results. A detailed model of Zion, including systems analysis models (initiating events, event trees, and fault trees), SSI and structure models, and piping models, was developed and used in assessing the seismic risk of the Zion nuclear power plant (FSAR). The simplified seismic risk methodology was applied to the LaSalle County Station nuclear power plant, a BWR; to further demonstrate its applicability, and if possible, to provide a basis for comparing the seismic risk from PWRs and BWRs. (orig./HP)

  13. Seismic Safety Margins Research Program, Phase I. Project II: seismic input. Compilation, assessment and expansion of the strong earthquake ground motion data base

    Energy Technology Data Exchange (ETDEWEB)

    Crouse, C B; Hileman, J A; Turner, B E; Martin, G R

    1980-04-01

    A catalog has been prepared which contains information for: (1) world-wide, ground-motion accelerograms, (2) the accelerograph sites where these records were obtained, and (3) the seismological parameters of the causative earthquakes. The catalog is limited to data for those accelerograms which have been digitized and published. In addition, the quality and completeness of these data are assessed. This catalog is unique because it is the only publication which contains comprehensive information on the recording conditions of all known digitized accelerograms. However, information for many accelerograms is missing. Although some literature may have been overlooked, most of the missing data has not been published. Nevertheless, the catalog provides a convenient reference and useful tool for earthquake engineering research and applications.

  14. Seismic analysis response factors and design margins of piping systems

    International Nuclear Information System (INIS)

    Shieh, L.C.; Tsai, N.C.; Yang, M.S.; Wong, W.L.

    1985-01-01

    The objective of the simplified methods project of the Seismic Safety Margins Research Program is to develop a simplified seismic risk methodology for general use. The goal is to reduce seismic PRA costs to roughly 60 man-months over a 6 to 8 month period, without compromising the quality of the product. To achieve the goal, it is necessary to simplify the calculational procedure of the seismic response. The response factor approach serves this purpose. The response factor relates the median level response to the design data. Through a literature survey, we identified the various seismic analysis methods adopted in the U.S. nuclear industry for the piping system. A series of seismic response calculations was performed. The response factors and their variabilities for each method of analysis were computed. A sensitivity study of the effect of piping damping, in-structure response spectra envelop method, and analysis method was conducted. In addition, design margins, which relate the best-estimate response to the design data, are also presented

  15. Seismic margins review of nuclear power plants: Fragility aspects

    International Nuclear Information System (INIS)

    Ravindra, M.K.; Hardy, G.S.; Hashimoto, P.S.

    1987-01-01

    The fragility analysis is utilised in the seismic margin review in initial screening of certain components in the plant based on their generically high seismic capacities. A detailed walkdown of the plant is conducted to confirm that the initial screening is valid i.e., the generically high seismic capacity components do not possess any potential weaknesses (e.g., inadequate bracing, inadequate anchorage and potential systems interaction). For the components that are screened in, their seismic capacities are evaluated using either a probabilistic analysis of a deterministic evaluation. Based on a system analysis, the Boolean expressions for critical accident sequences are derived. These Boolean expressions are quantified using the component fragilities and nonseismic unavailabilities of components. The final product is the High Confidence Low Probability of Failure (HCLPF) capacity of the plant and the identification of potential seismic vulnerabilities in the plant. The objective of the paper is to describe the application of fragility analysis procedures in the seismic margin review of Maine Yankee and to document the insights obtained in this trial plant review. (orig./HP)

  16. Deformation patterns and seismic hazard along the eastern Sunda margin

    Science.gov (United States)

    Kopp, Heidrun; Djajadihardja, Yusuf; Flueh, Ernst R.; Hindle, David; Klaeschen, Dirk; Mueller, Christian; Planert, Lars; Reichert, Christian; Shulgin, Alexey; Wittwer, Andreas

    2010-05-01

    The eastern Sunda margin offshore Java, Bali, Lombok and Sumba is the site of oceanic subduction of the Indo-Australian plate underneath the Indonesian archipelago. Data from a suite of geophysical experiments conducted between 1997-2006 using RV SONNE as platform include seismic and seismological studies, potential field measurements and high-resolution seafloor bathymetry mapping. Tomographic inversions provide an image of the ongoing deformation of the forearc and the deep subsurface. We investigate the role of various key mechanisms that shape the first-order features characterizing the present margin architecture. Our contribution evaluates the differences in architecture and evolution along the Java forearc from a marine perspective to better understand the variation in tectonic styles and segmentation of the convergent margin, including its seismic risk potential.

  17. Enhancing the seismic margin review methodology to obtain risk insights

    International Nuclear Information System (INIS)

    Budnitz, R.J.

    1992-01-01

    This paper discusses methods for obtaining risk insights from the seismic margin review (SMR) methodology. The SMR methodology was originally developed in 1984-1987 with the objective of analyzing an individual nuclear power plant to ascertain whether the plant has the ability to withstand earthquakes substantially beyond the design-basis earthquake without suffering a core-damage accident. Recently, in the context of Nuclear Regulatory Commission's (NRC's) Individual Plant Evaluation for External Events (IPEEE) program, the SMR methodology has been developed further by NRC to allow plants to identify plant-specific vulnerabilities (in the IPEEE sense) to seismic events. The objective of these enhancements has been to provide a methodology for IPEEE seismic review that is substantially less expensive than a full-scope seismic PRA, but that achieves the IPEEE's vulnerability-search objectives. In this paper, the steps involved in the enhanced methodology are discussed

  18. Assessing submarine gas hydrate at active seeps on the Hikurangi Margin, New Zealand, using controlled source electromagnetic data with constraints from seismic, geochemistry, and heatflow data

    Science.gov (United States)

    Schwalenberg, K.; Haeckel, M.; Pecher, I. A.; Toulmin, S. J.; Hamdan, L. J.; Netzeband, G.; Wood, W.; Poort, J.; Jegen, M. D.; Coffin, R. B.

    2009-12-01

    Electrical resistivity is one of the key properties useful for evaluating submarine gas hydrate deposits. Gas hydrates are electrically insulating in contrast to the conductive pore fluid. Where they form in sufficient quantities the bulk resistivity of the sub-seafloor is elevated. CSEM data were collected in 2007 as part of the German - International “New Vents” project on R/V Sonne, cruise SO191, at three target areas on the Hikurangi subduction margin, New Zealand. The margin is characterized by widespread bottom simulating reflectors (BSR), seep structures, and active methane and fluid venting indicating the potential for gas hydrate formation. Opouawe Bank is one of the ridge and basin systems on the accretionary wedge and is located off the Wairarapa coast at water depths of 1000-1100 m. The first observed seep sites (North Tower, South Tower, Pukeko, Takahe, and Tui) were identified from individual gas flares in hydro-acoustic data and video observations during voyages on R/V Tangaroa. Seismic reflection data collected during SO191 subsequently identified more than 25 new seep structures. Two intersecting CSEM profiles have been surveyed across North Tower, South Tower, and Takahe. 1-D inversion of the data reveals anomalously high resistivities at North Tower and South Tower, moderately elevated resistivities at Takahe, and normal background resistivities away from the seeps. The high resistivities are attributed to gas hydrate layers at intermediate depths beneath the seeps. At South Tower the hydrate concentration could be possibly as much as 25% of the total sediment volume within a 50m thick layer. This conforms with geochemical pore water analyses which show a trend of increased methane flux towards South Tower. At Takahe, gas pockets and patchy gas hydrate, as well as sediment heterogeneities and carbonates, or temperature driven upward fluid flow indicated by the observed higher heat flow at this site may explain the resistivity pattern

  19. Seismic safety margin research program. Program plan, Revision II

    International Nuclear Information System (INIS)

    Smith, P.D.; Tokarz, F.J.; Bernreuter, D.L.; Cummings, G.E.; Chou, C.K.; Vagliente, V.N.; Johnson, J.J.; Dong, R.G.

    1978-01-01

    The document has been prepared pursuant to the second meeting of the Senior Research Review Group of the Seismic Safety Margin Research Program (SSMRP), which was held on June 15, 16, 1978. The major portion of the material contained in the document is descriptions of specific subtasks to be performed on the SSMRP. This is preceded by a brief discussion of the objective of the SSMRP and the approach to be used. Specific subtasks to be performed in Phase I of the SSMRP are as follows: (1) plant/site selection, (2) seismic input, (3) soil structure interaction, (4) structural building response, (5) structural sub-system response, (6) fragility, (7) system analysis, and (8) Phase II task definition

  20. Evolution of a seismic risk assessment technique

    International Nuclear Information System (INIS)

    Wells, J.E.; Cummings, G.E.

    1985-01-01

    To assist the NRC in its licensing evaluation role the Seismic Safety Margins Research Program (SSMRP) was started at LLNL in 1978. Its goal was to develop tools and data bases to evaluate the probability of earthquake caused radioactive releases from commercial nuclear power plants. The methodology was finalized in 1982 and a seismic risk assessment of the Zion Nuclear Power Plant was finished in 1983. Work continues on the study of the LaSalle Boiling Water Reactor. This paper will discuss some of the effects of the assumptions made during development of the systems analysis techniques used in SSMRP in light of the results obtained on studies to date. 5 refs

  1. Seismic safety margin research program. Program plan, Revision I

    International Nuclear Information System (INIS)

    Smith, P.D.; Tokarz, F.J.; Bernreuter, D.L.; Cummings, G.E.; Chou, C.K.; Vagliente, V.N.

    1978-01-01

    The overall objective of the SSMRP is to develop mathematical models that realistically predict the probability of radioactive releases from seismically induced events in nuclear power plants. These models will be used for four purposes: (1) To perform sensitivity studies to determine the weak links in seismic methodology. The weak links will then be improved by research and development. (2) To estimate the probability of release for a plant. It is believed that the major difficulty in the program will be to obtain acceptably small confidence limits on the probability of release. (3) To estimate the conservatisms in the Standard Review Plan (SRP) seismic design methodology. This will be done by comparing the results of the SRP methodology and the methodology resulting from the research and development in (1). (4) To develop an improved seismic design methodology based on probability. The Phase I objective proposed in this report is to develop mathematical models which will accomplish the purposes No. 1 and No. 2 with simplified assumptions such as linear elastic analysis, limited assessment on component fragility (considering only accident sequences leading to core melt), and simplified safety system

  2. Various types of reported seismic margins and their uses

    International Nuclear Information System (INIS)

    Kennedy, R.P.

    1985-01-01

    Nuclear power plant structures and safety-related systems have been generally designed conservatively for a safe shutdown earthquake (SSE) and more conservatively for a smaller operating basis earthquake (OBE). Depending upon the relative conservatism of the design criteria, either the SSE or the OBE will control the design. In recent years, increasing knowledge in the geoscience field has led to a better understanding that, although highly unlikely, it is possible for the nuclear power plant to be subjected to earthquake ground motion greater than the ground motion for which the plant was designed. For this reason, interest has developed in demonstrating that nuclear plant structures and safety-related systems can safely withstand earthquake ground motion larger than their design earthquake ground motions (SSE and OBE). Within this paper, this larger-than-design earthquake ground motion will be called the seismic margin earthquake (SME) to distinguish it from the design earthquakes. The goal is to determine the performance of already-designed structures, components, and systems when subjected to the SME. Different and generally more liberal criteria should be used when evaluating the performance of structures, components and systems for the SME than were used in design. Retrofit, and redesign, should only be contemplated if one cannot show a seismic margin greater than unity for the SME using these more liberal criteria. In other words, the SME is not a design earthquake. It is not a replacement for the SSE and generally has nothing to do with design. The SME is a performance-check earthquake

  3. Handbook of nuclear power plant seismic fragilities, Seismic Safety Margins Research Program

    International Nuclear Information System (INIS)

    Cover, L.E.; Bohn, M.P.; Campbell, R.D.; Wesley, D.A.

    1983-12-01

    The Seismic Safety Margins Research Program (SSMRP) has a gola to develop a complete fully coupled analysis procedure (including methods and computer codes) for estimating the risk of an earthquake-induced radioactive release from a commercial nuclear power plant. As part of this program, calculations of the seismic risk from a typical commercial nuclear reactor were made. These calculations required a knowledge of the probability of failure (fragility) of safety-related components in the reactor system which actively participate in the hypothesized accident scenarios. This report describes the development of the required fragility relations and the data sources and data reduction techniques upon which they are based. Both building and component fragilities are covered. The building fragilities are for the Zion Unit 1 reactor which was the specific plant used for development of methodology in the program. Some of the component fragilities are site-specific also, but most would be usable for other sites as well

  4. Summary report on the Seismic Safety Margins Research Program

    International Nuclear Information System (INIS)

    Cummings, G.E.

    1986-01-01

    The Seismic Safety Margins Research Program (SSMRP) was a program to develop a complete, fully coupled analysis procedure (including methods and computer codes) for estimating the risk of an earthquake-induced radioactive release from a commercial nuclear power plant. The SSMRP was the first effort to trace seismically induced failure modes in a reactor system down to the individual component level, and to take into account common-cause earthquake-induced failures at the component level. This report summarizes methods and results generated by SSMRP. The SSMRP method makes use of three computer codes, HAZARD, SMACS and SEISIM to calculate ground motion acceleration time histories, structure and component responses and failure, and radioactive release probabilities. To demonstrate the methodology, an analysis was done of the Zion Nuclear Power Plant. The median frequency of core melt was computed to be 3E-5 per year, with upper (90%) and lower (10%) bounds of 8E-4 and 6E-7 per year. The main contribution to risk came from earthquakes about 2 through 4 times the design basis earthquake level. Risk was dominated by structural and inter-building piping failures and loss of off-site power. Sensitivity studies were undertaken to test assumptions and modeling procedures relative to soil-structure interaction effects, feed-and-bleed cooling, and structural failures. Assumptions made could have an order-of-magnitude effect on core melt frequency. Also, guidelines were developed for simplifying the SSMRP method, and importance rankings were generated based on the Zion analysis. 56 refs., 6 figs

  5. Seismic margin analysis for Kashiwazaki Kariwa ABWR plant considering the Niigataken Chuetsu-oki earthquake

    International Nuclear Information System (INIS)

    Matsuo, Toshihiro; Nagasawa, Kazuyuki; Kawamura, Shinichi; Ueki, Takashi; Higuchi, Tomokazu; Sakaki, Isao

    2009-01-01

    Seismic Margin Analysis (SMA) study was conducted for Kashiwazaki Kariwa (KK) ABWR representative plant (unit 6). Considering that the installation behaved in a safe manner during and after the Niigataken Chuetsu-oki (NCO) Earthquake which significantly exceeded the level of the seismic input taken into account in the design of the plant, the study to find out how much margin the ABWR plant had toward the same seismic motion was conducted. In this study fragility analyses were conducted for SSCs that were included in the accident sequences and that were considered to have relatively small margin taking EPRI margin analysis method into consideration. In order to calculate plant level seismic margin Min-Max method was adopted. As the result of this study, the plant level High Confidence Low Probability of Failure (HCLPF) acceleration for unit 6 was calculated more than tripled NCO earthquake motion. (author)

  6. Seismic hazard assessment: Issues and alternatives

    Science.gov (United States)

    Wang, Z.

    2011-01-01

    Seismic hazard and risk are two very important concepts in engineering design and other policy considerations. Although seismic hazard and risk have often been used inter-changeably, they are fundamentally different. Furthermore, seismic risk is more important in engineering design and other policy considerations. Seismic hazard assessment is an effort by earth scientists to quantify seismic hazard and its associated uncertainty in time and space and to provide seismic hazard estimates for seismic risk assessment and other applications. Although seismic hazard assessment is more a scientific issue, it deserves special attention because of its significant implication to society. Two approaches, probabilistic seismic hazard analysis (PSHA) and deterministic seismic hazard analysis (DSHA), are commonly used for seismic hazard assessment. Although PSHA has been pro-claimed as the best approach for seismic hazard assessment, it is scientifically flawed (i.e., the physics and mathematics that PSHA is based on are not valid). Use of PSHA could lead to either unsafe or overly conservative engineering design or public policy, each of which has dire consequences to society. On the other hand, DSHA is a viable approach for seismic hazard assessment even though it has been labeled as unreliable. The biggest drawback of DSHA is that the temporal characteristics (i.e., earthquake frequency of occurrence and the associated uncertainty) are often neglected. An alternative, seismic hazard analysis (SHA), utilizes earthquake science and statistics directly and provides a seismic hazard estimate that can be readily used for seismic risk assessment and other applications. ?? 2010 Springer Basel AG.

  7. Subsystem response analysis for the Seismic Safety Margins Research Program

    International Nuclear Information System (INIS)

    Chuang, T.Y.

    1981-01-01

    A review of the state-of-the-art of seismic qualification methods of subsystem has been completed. This task assesses the accuracy of seismic analysis techniques to predict dynamic response, and also identifies and quantifies sources of random and modeling undertainty in subsystem response determination. The subsystem has been classified as two categories according to the nature of support: multiply supported subsystems (e.g., piping systems) and singly supported subsystems (e.g., pumps, turbines, electrical control panels, etc.). The mutliply supported piping systems are analyzed by multisupport input time history method. The input motions are the responses of major structures. The dynamic models of the subsystems identified by the event/fault tree are created. The responses calculated by multisupport input time history method are consistent with the fragility parameters. These responses are also coordinated with the event/fault tree description. The subsystem responses are then evaluated against the fragility curves of components and systems and incorporated in the event/fault tree analysis. (orig./HP)

  8. Seismic Safety Margins Research Program: Phase II program plan (FY 83-FY 84)

    International Nuclear Information System (INIS)

    Bohn, M.P.; Bernreuter, D.L.; Cover, L.E.; Johnson, J.J.; Shieh, L.C.; Shukla, S.N.; Wells, J.E.

    1982-01-01

    The Seismic Safety Margins Research Program (SSMRP) is an NRC-funded, multiyear program conducted by Lawrence Livermore National Laboratory (LLNL). Its goal is to develop a complete, fully coupled analysis procedure (including methods and computer codes) for estimating the risk of an earthquake-caused radioactive release from a commercial nuclear power plant. The analysis procedure is based upon a state-of-the-art evaluation of the current seismic analysis and design process and explicitly includes the uncertainties inherent in such a process. The results will be used to improve seismic licensing requirements for nuclear power plants. As currently planned, the SSMRP will be completed in September, 1984. This document presents the program plan for work to be done during the remainder of the program. In Phase I of the SSMRP, the necessary tools (both computer codes and data bases) for performing a detailed seismic risk analysis were identified and developed. Demonstration calculations were performed on the Zion Nuclear Power Plant. In the remainder of the program (Phase II) work will be concentrated on developing a simplified SSMRP methodology for routine probabilistic risk assessments, quantitative validation of the tools developed and application of the simplified methodology to a Boiling Water Reactor. (The Zion plant is a pressurized water reactor.) In addition, considerable effort will be devoted to making the codes and data bases easily accessible to the public

  9. Deep seismic profiling of the continents and their margins

    DEFF Research Database (Denmark)

    Ito, T.; Iwasaki, T.; Thybo, Hans

    2009-01-01

    , in many applications, the methods are used up-to their limits at the present technological state. Therefore, development of methods has high priority in the seismic community. This volume provides an overview of recent development of deep seismic techniques and their application to the imaging and probing......Application of deep seismic methods to studies of the crust and lithospheric mantle receives considerable interest and the methods are constantly refined and new methods are developed, which allows the extension of studies to new subjects and regions. Deep seismic methods are applied to a long...

  10. Contributions to knowledge of the continental margin of Uruguay. Uruguayan continental margin: Physiographic and seismic analysis

    International Nuclear Information System (INIS)

    Preciozzi, F

    2014-01-01

    This work is about the kind of continental margins such as a )Atlantic type passive margins which can be hard or soft b) An active or Pacific margins that because of the very frequent earthquakes develop a morphology dominated by tectonic processes. The Uruguayan continental margin belongs to a soft Atlantic margin

  11. Structure of the Gabon Margin from integrated seismic reflection and gravity data

    NARCIS (Netherlands)

    Dupre, S.; Cloetingh, S.A.P.L.; Bertotti, G.V.

    2011-01-01

    In the South Gabon Basin, deep multi-channel seismic reflection and gravity modeling analysis have shed light on key features of the structure of the margin. The thinned continental crust beneath the Gabon Margin appears to be composed of two distinct layers, separated by a clear, strong and more or

  12. Evaluation of seismic margins for an in-plant piping system

    International Nuclear Information System (INIS)

    Kot, C.A.; Srinivasan, M.G.; Hsieh, B.J.

    1991-01-01

    Earthquake experience as well as experiments indicate that, in general, piping systems are quite rugged in resisting seismic loadings. Therefore there is a basis to hold that the seismic margin against pipe failure is very high for systems designed according to current practice. However, there is very little data, either from tests or from earthquake experience, on the actual margin or excess capacity (against failure from seismic loading) of in-plant piping systems. Design of nuclear power plant piping systems in the US is governed by the criteria given in the ASME Boiler and Pressure Vessel (B ampersand PV) Code, which assure that pipe stresses are within specified allowable limits. Generally linear elastic analytical methods are used to determine the stresses in the pipe and forces in pipe supports. The objective of this study is to verify that piping designed according to current practice does indeed have a large margin against failure and to quantify the excess capacity for piping and dynamic pipe supports on the basis of data obtained in a series of high-level seismic experiments (designated SHAM) on an in-plant piping system at the HDR (Heissdampfreaktor) Test Facility in Germany. Note that in the present context, seismic margin refers to the deterministic excess capacities of piping or supports compared to their design capacities. The excess seismic capacities or margins of a prototypical in-plant piping system and its components are evaluated by comparing measured inputs and responses from high-level simulated seismic experiments with design loads and allowables. Large excess capacities are clearly demonstrated against pipe and overall system failure with the lower bound being about four. For snubbers the lower bound margin is estimated at two and for rigid strut supports at five. 4 refs., 2 figs., 2 tabs

  13. Subsystem response review. Seismic safety margins research program

    International Nuclear Information System (INIS)

    Kennedy, R.P.; Campbell, R.D.; Wesley, D.A.; Kamil, H.; Gantayat, A.; Vasudevan, R.

    1981-07-01

    A study was conducted to document the state of the art in seismic qualification of nuclear power plant components and subsystems by analysis and testing and to identify the sources and magnitude of the uncertainties associated with analysis and testing methods. The uncertainties are defined in probabilistic terms for use in probabilistic seismic risk studies. Recommendations are made for the most appropriate subsystem response analysis methods to minimize response uncertainties. Additional studies, to further quantify testing uncertainties, are identified. Although the general effect of non-linearities on subsystem response is discussed, recommendations and conclusions are based principally on linear elastic analysis and testing models. (author)

  14. Seismic Safety Margins Research Program (Phase I). Project IV. Structural building response; Structural Building Response Review

    International Nuclear Information System (INIS)

    Healey, J.J.; Wu, S.T.; Murga, M.

    1980-02-01

    As part of the Phase I effort of the Seismic Safety Margins Research Program (SSMRP) being performed by the University of California Lawrence Livermore Laboratory for the US Nuclear Regulatory Commission, the basic objective of Subtask IV.1 (Structural Building Response Review) is to review and summarize current methods and data pertaining to seismic response calculations particularly as they relate to the objectives of the SSMRP. This material forms one component in the development of the overall computational methodology involving state of the art computations including explicit consideration of uncertainty and aimed at ultimately deriving estimates of the probability of radioactive releases due to seismic effects on nuclear power plant facilities

  15. Interim Report on Metallic Component Margins Under High Seismic Loads. Survey of Existing Practices and Status of Benchmark Work

    International Nuclear Information System (INIS)

    2015-01-01

    OECD/NEA/CSNI Working Group on Integrity and Ageing of Components and Structures (WGIAGE) has the main mission to advance the current understanding of those aspects relevant to ensuring the integrity of structures, systems and components under design and beyond design loads, to provide guidance in choosing the optimal ways of dealing with challenges to the integrity of operating as well as new nuclear power plants, and to make use of an integrated approach to design, safety and plant life management. The activity (CAPS) of the WGIAGE group, entitled 'Metallic Component Margins under High Seismic Loads (MECOS)', was initially proposed by the metal sub-group of WGIAGE and approved by the CSNI in June 2012 as a Fukushima activity (F-CAPS). The proposal is aimed to assess the consequences of external hazards on plant safety. The main objectives of the MECOS project were to quantify the existing margins in seismic analysis of safety class components for high seismic loads and assess the existing design practices within a benchmark activity. The first phase of MECOS work included a survey on the existing seismic regulations and design analysis methods in the member countries. The survey was conducted by means of a questionnaire and a total of 24 questions were asked. The questionnaire consists of three parts: Seismic Input, Seismic Design Basis, and Beyond Seismic Design Basis. The majority of the respondents use the Standard or Modified Shape Spectrum and only a few countries are using the Uniform Seismic Hazard Spectra (UHS) in their seismic design regulations. All of the respondents have minimum seismic demand in their national or adopted standards. The number of defined and used seismic levels for the design of mechanical components is one or two. Almost all of the respondents are using combined testing and analysis methods for seismic qualification and design. Some countries (e.g. Canada, Finland, USA, France, Japan and UK) have specific requirements for

  16. Seismic structural fragility investigation for the Zion Nuclear Power Plant. Seismic safety margins research program (phase 1)

    International Nuclear Information System (INIS)

    Wesley, D.A.; Hashimoto, P.S.

    1981-10-01

    An evaluation of the seismic capacity of the essential structures for the Zion Nuclear Power Plant in Zion, Illinois, was conducted as part of the Seismic Safety Margins Research Program (SSMRP). The structures included the reactor containment building, the turbine/auxiliary building, and the crib house (intake structure). The evaluation was devoted to seismically induced failures rather than those resulting from combined Loss of Coolant Accident (LOCA) or other extreme load combinations. The seismic loads used in the investigation were based on elastic analyses. The loads for the reactor containment and turbine/auxiliary buildings were developed by Lawrence Livermore Laboratory using time history analyses. The loads used for the crib house were the original seismic design loads developed by Sargent and Lundy. No non-linear seismic analyses were conducted. The seismic capacity of the structures accounted for the actual concrete and steel material properties including the aging of the concrete. Median centered properties were used throughout the evaluation including levels of damping considered appropriate for structures close to collapse as compared to the more conservative values used for design. The inelastic effects were accounted for using ductility modified response spectrum techniques based on system ductility ratios expected for structures near collapse. Sources of both inherent randomness and uncertainties resulting from lack of knowledge or approximations in analytical modelling were considered in developing the dispersion of the structural dynamic characteristics. Coefficients of variation were developed assuming lognormal distributions for all variables. The earthquake levels for many of the seismically induced failure modes are so high as to be considered physically incredible. (author)

  17. Study on seismic design margin based upon inelastic shaking test of the piping and support system

    International Nuclear Information System (INIS)

    Ishiguro, Takami; Eto, Kazutoshi; Ikeda, Kazutoyo; Yoshii, Toshiaki; Kondo, Masami; Tai, Koichi

    2009-01-01

    In Japan, according to the revised Regulatory Guide for Aseismic Design of Nuclear Power Reactor Facilities, September 2006, criteria of design basis earthquakes of Nuclear Power Reactor Facilities become more severe. Then, evaluating seismic design margin took on a great importance and it has been profoundly discussed. Since seismic safety is one of the major key issues of nuclear power plant safety, it has been demonstrated that nuclear piping system possesses large safety margins by various durability test reports for piping in ultimate conditions. Though the knowledge of safety margin has been accumulated from these reports, there still remain some technical uncertainties about the phenomenon when both piping and support structures show inelastic behavior in extremely high seismic excitation level. In order to obtain the influences of inelastic behavior of the support structures to the whole piping system response when both piping and support structures show inelastic behavior, we examined seismic proving tests and we conducted simulation analyses for the piping system which focused on the inelastic behavior of the support to the whole piping system response. This paper introduces major results of the seismic shaking tests of the piping and support system and the simulation analyses of these tests. (author)

  18. Seismic safety margins research program. Project I SONGS 1 AFWS Project

    International Nuclear Information System (INIS)

    Chuang, T.Y.; Smith, P.D.; Dong, R.G.; Bernreuter, D.L.; Bohn, M.P.; Cummings, G.E.; Wells, J.E.

    1981-01-01

    The seismic qualification requirements of auxiliary feedwater systems (AFWS) of Pressurized Water Reactors (PWR) were developed over a number of years. These are formalized in the publication General Design Criteria (Appendix A to 10CFR50). The full recognition of the system as an engineered safety feature did not occur until publication of the Standard Review Plan (1975). Efforts to determine how to backfit seismic requirements to earlier plants has been undertaken primarily in the Systematic Evaluation Program (SEP) for a limited number of operating reactors. Nuclear Reactor Research (RES) and NRR have requested LLNL to perform a probabilistic study on the AFWS of San Onofre Nuclear Generating Station (SONGS) Unit 1 utilizing the tools developed by the Seismic Safety Margins Research Program (SSMRP). The main objectives of this project are to: identify the weak links of AFWS; compare the failure probabilities of SONGS 1 and Zion 1 AFWS: and compare the seismic responses due to different input spectra and design values

  19. Seismic hazard assessment of Iran

    Directory of Open Access Journals (Sweden)

    M. Ghafory-Ashtiany

    1999-06-01

    Full Text Available The development of the new seismic hazard map of Iran is based on probabilistic seismic hazard computation using the historical earthquakes data, geology, tectonics, fault activity and seismic source models in Iran. These maps have been prepared to indicate the earthquake hazard of Iran in the form of iso-acceleration contour lines, and seismic hazard zoning, by using current probabilistic procedures. They display the probabilistic estimates of Peak Ground Acceleration (PGA for the return periods of 75 and 475 years. The maps have been divided into intervals of 0.25 degrees in both latitudinal and longitudinal directions to calculate the peak ground acceleration values at each grid point and draw the seismic hazard curves. The results presented in this study will provide the basis for the preparation of seismic risk maps, the estimation of earthquake insurance premiums, and the preliminary site evaluation of critical facilities.

  20. Seismic studies of crustal structure and tectonic evolution across the central California margin and the Colorado Plateau margin

    Science.gov (United States)

    Howie, John Mark

    This thesis presents results from two integrated deep-crustal seismic-reflection and wide-angle-reflection/refraction studies that improve our understanding of crustal structure and tectonic evolution in two tectonically active areas of the western United States. A multi-faceted approach to the study of crustal structure includes the use of compressional and shear wave seismic data. Supplementing the controlled source seismic observations with seismicity, gravity, heat flow, laboratory measurements and available geologic information allows a much improved understanding of crustal structure and tectonic evolution than would be available from the seismic data alone. Chapter 1 introduces the data integration strategy applied to the studies completed. In Chapter 2, an integrated crustal-velocity model across the south-central California margin west of the San Adreas fault is presented. The crustal structure defines tectonostratigraphic terranes 15 to 20 km thick underlain by a 6-km-thick high-velocity layer (6.8-7.0 km/s) interpreted as tectonically underplated oceanic crust. Structures defined in the oceanic crust indicate significant compressional and strike-slip deformation within the oceanic crust that probably formed during the final stages of subduction from 24-16 Ma. In Chapter 3, the crustal model from Chapter 2 is used as a constraint for models of the tectonic evolution of the Pacific-North American transform plate boundary. By combining the crustal structure with thermal models for asthenospheric upwelling associated with a slab-free window, I find that the mantle lithosphere east of the coast beneath south-central California probably delaminated from the oceanic crust, stranding the oceanic crust beneath the margin. In Chapter 4, results from a high-resolution reflection experiment in central Arizona across the southwestern edge of the Colorado Plateau address the relationship between strength of the crust and localization of extensional tectonism. A low

  1. Development of Seismic Safety Assessment Technology for Containment Structure

    Energy Technology Data Exchange (ETDEWEB)

    Jang, J.B.; Suh, Y.P.; Lee, J.R. [Korea Electric Power Research Institute, Taejon (Korea)

    2002-07-01

    This final report is made based on the research results of seismic analysis and seismic margin assessment field, carried out during 3rd stage ('01.4.1{approx}'02.3.31) under financial support of MOST(Ministry of Science and Technology). The objective of this research is to develop the soil - structure interaction analysis technique with high reliability, the main research subjects, performed during 3rd stage are as follows. 1) Preparation of user's guide manual for SSI analysis with high accuracy. 2) Sensitivity analysis of effective shear strain and seismic input motion. 3) Database construction of Hualien earthquake recorded data. (author). 21 refs., 27 figs., 2 tabs.

  2. Seismic Safety Margins Research Program. Phase I. Interim definition of terms

    International Nuclear Information System (INIS)

    Smith, P.D.; Dong, R.G.

    1980-01-01

    This report documents interim definitions of terms in the Seismic Safety Margins Research Program (SSMRP). Intent is to establish a common-based terminology integral to the probabilistic methods that predict more realistically the behavior of nuclear power plants during an earthquake. These definitions are a response to a request by the Nuclear Regulatory Commission Advisory Committee on Reactor Safeguards at its meeting held November 15-16, 1979

  3. Probabilistic safety assessment for seismic events

    International Nuclear Information System (INIS)

    1993-10-01

    This Technical Document on Probabilistic Safety Assessment for Seismic Events is mainly associated with the Safety Practice on Treatment of External Hazards in PSA and discusses in detail one specific external hazard, i.e. earthquakes

  4. Seismic evidence of Messinian salt in opposite margins of West Mediterranean

    Science.gov (United States)

    Mocnik, Arianna; Camerlenghi, Angelo; Del Ben, Anna; Geletti, Riccardo; Wardell, Nigel; Zgur, Fabrizio

    2015-04-01

    The post drift Messinian Salinity Crisis (MSC) affected the whole Mediterranean basin, with deposition of evaporitic sequences in the deep basins, in the lower continental slopes, and in several shallower marginal basins; usually, in the continental margins, the MSC originated noticeable erosional truncations that locally cause important hiatuses in the pre-Messinian sequences, covered by the Plio-Quaternary sediments. In this work we focus on the MSC seismic signature of two new seismic datasets acquired in 2010 (West Sardinia offshore) and in 2012 (within the Eurofleet project SALTFLU in the South Balearic continental margin and the northern Algero abyssal plain). The "Messinian trilogy" recognized in the West-Mediterranean abyssal plain, is characterized by different seismic facies: the Lower evaporite Unit (LU), the salt Mobile Unit (MU) and the Upper evaporite mainly gypsiferous Unit (UU). Both seismic datasets show the presence of the Messinian trilogy also if the LU is not always clearly interpretable due to the strong seismic signal absorption by the halite layers; the salt thickness of the MU is similar in both the basins as also the thickness and stratigraphy of the UU. The Upper Unit (UU) is made up of a well reflecting package of about 10 reflectors, partially deformed by salt tectonic and characterized by a thin transparent layer that we interpreted as salt sequence inner the shallower part of the UU. Below the stratified UU, the MU exhibits a transparent layer in the deep basin and also on the foot of the slope, where a negative reflector, related to the high interval velocity of salt, marks its base. The halokinetic processes are not homogeneously distributed in the region, forming a great number of diapirs on the foot of the slope (due to the pression of the slided sediments) and giant domes toward the deep basin (due to the higher thickness of the Plio-quaternary sediments). This distribution seems to be related to the amount of salt and of the

  5. Input for seismic hazard assessment using Vrancea seismic source region

    International Nuclear Information System (INIS)

    Ivan, Iren-Adelina; Enescu, B.D.; Pantea, A.

    1998-01-01

    We use an extended and combined data base including historical and modern, qualitative and quantitative data, i.e., more than 25 events during the period 1790 - 1990 with epicentral/maximum intensities ranging from X to V degree (MSK scale), the variation interval of isoseismal curves ranging from IX th to III rd degree. The data set was analysed using both the sum phasor techniques of Ridelek and Sacks (1984) for different magnitudes and depth intervals and the Stepp's method. For the assessment of seismic hazard we need a pattern of seismic source regions including an estimation for the maximum expected magnitude and the return period for the studied regions. Another necessary step in seismic hazard assessment is to develop attenuation relationships specific to a seismogenic zone, particularly to sub-crustal earthquakes of Vrancea region. The conceptual frame involves the use of appropriate decay models and consideration of the randomness in the attenuation, taking into account the azimuthal variation of the isoseist shapes. (authors)

  6. Seismic Risk Assessment of Italian Seaports Using GIS

    International Nuclear Information System (INIS)

    Bartolomei, Anna; Corigliano, Mirko; Lai, Carlo G.

    2008-01-01

    Seaports are crucial elements in the export and import of goods and/or on the flow of travellers in the tourism industry of many industrialised nations included Italy. Experience gained from recent earthquakes (e.g. 1989 Loma Prieta in USA, 1995 Hyogoken-Nanbu and 2003 Tokachi-Oki in Japan) have dramatically demonstrated the seismic vulnerability of seaport structures and the severe damage that can be caused by ground shaking. In Italy, the Department of Civil Protection has funded a research project to develop a methodology for the seismic design of new marginal wharves and assessment of existing structures at seaports located in areas of medium or high seismicity. This paper shows part of the results of this research project, currently underway, with particular reference to the seismic risk assessment through an interactive, geographically referenced database (GIS). Standard risk assessment have been carried out for the Gioia Tauro port in Calabria (Italy) using the empirical curves implemented by the National Institute of Building Sciences (NIBS, 2004)

  7. Seismic Risk Assessment of Italian Seaports Using GIS

    Science.gov (United States)

    Bartolomei, Anna; Corigliano, Mirko; Lai, Carlo G.

    2008-07-01

    Seaports are crucial elements in the export and import of goods and/or on the flow of travellers in the tourism industry of many industrialised nations included Italy. Experience gained from recent earthquakes (e.g. 1989 Loma Prieta in USA, 1995 Hyogoken-Nanbu and 2003 Tokachi-Oki in Japan) have dramatically demonstrated the seismic vulnerability of seaport structures and the severe damage that can be caused by ground shaking. In Italy, the Department of Civil Protection has funded a research project to develop a methodology for the seismic design of new marginal wharves and assessment of existing structures at seaports located in areas of medium or high seismicity. This paper shows part of the results of this research project, currently underway, with particular reference to the seismic risk assessment through an interactive, geographically referenced database (GIS). Standard risk assessment have been carried out for the Gioia Tauro port in Calabria (Italy) using the empirical curves implemented by the National Institute of Building Sciences (NIBS, 2004).

  8. Multi scenario seismic hazard assessment for Egypt

    Science.gov (United States)

    Mostafa, Shaimaa Ismail; Abd el-aal, Abd el-aziz Khairy; El-Eraki, Mohamed Ahmed

    2018-05-01

    Egypt is located in the northeastern corner of Africa within a sensitive seismotectonic location. Earthquakes are concentrated along the active tectonic boundaries of African, Eurasian, and Arabian plates. The study area is characterized by northward increasing sediment thickness leading to more damage to structures in the north due to multiple reflections of seismic waves. Unfortunately, man-made constructions in Egypt were not designed to resist earthquake ground motions. So, it is important to evaluate the seismic hazard to reduce social and economic losses and preserve lives. The probabilistic seismic hazard assessment is used to evaluate the hazard using alternative seismotectonic models within a logic tree framework. Alternate seismotectonic models, magnitude-frequency relations, and various indigenous attenuation relationships were amended within a logic tree formulation to compute and develop the regional exposure on a set of hazard maps. Hazard contour maps are constructed for peak ground acceleration as well as 0.1-, 0.2-, 0.5-, 1-, and 2-s spectral periods for 100 and 475 years return periods for ground motion on rock. The results illustrate that Egypt is characterized by very low to high seismic activity grading from the west to the eastern part of the country. The uniform hazard spectra are estimated at some important cities distributed allover Egypt. The deaggregation of seismic hazard is estimated at some cities to identify the scenario events that contribute to a selected seismic hazard level. The results of this study can be used in seismic microzonation, risk mitigation, and earthquake engineering purposes.

  9. Probabilistic seismic hazard assessment. Gentilly 2

    International Nuclear Information System (INIS)

    1996-03-01

    Results of this probabilistic seismic hazard assessment were determined using a suite of conservative assumptions. The intent of this study was to perform a limited hazard assessment that incorporated a range of technically defensible input parameters. To best achieve this goal, input selected for the hazard assessment tended to be conservative with respect to selection of attenuation modes, and seismicity parameters. Seismic hazard estimates at Gentilly 2 were most affected by selection of the attenuation model. Alternative definitions of seismic source zones had a relatively small impact on seismic hazard. A St. Lawrence Rift model including a maximum magnitude of 7.2 m b in the zone containing the site had little effect on the hazard estimate relative to other seismic source zonation models. Mean annual probabilities of exceeding the design peak ground acceleration, and the design response spectrum for the Gentilly 2 site were computed to lie in the range of 0.001 to 0.0001. This hazard result falls well within the range determined to be acceptable for nuclear reactor sites located throughout the eastern United States. (author) 34 refs., 6 tabs., 28 figs

  10. Seismic risk assessment and application in the central United States

    Science.gov (United States)

    Wang, Z.

    2011-01-01

    Seismic risk is a somewhat subjective, but important, concept in earthquake engineering and other related decision-making. Another important concept that is closely related to seismic risk is seismic hazard. Although seismic hazard and seismic risk have often been used interchangeably, they are fundamentally different: seismic hazard describes the natural phenomenon or physical property of an earthquake, whereas seismic risk describes the probability of loss or damage that could be caused by a seismic hazard. The distinction between seismic hazard and seismic risk is of practical significance because measures for seismic hazard mitigation may differ from those for seismic risk reduction. Seismic risk assessment is a complicated process and starts with seismic hazard assessment. Although probabilistic seismic hazard analysis (PSHA) is the most widely used method for seismic hazard assessment, recent studies have found that PSHA is not scientifically valid. Use of PSHA will lead to (1) artifact estimates of seismic risk, (2) misleading use of the annual probability of exccedance (i.e., the probability of exceedance in one year) as a frequency (per year), and (3) numerical creation of extremely high ground motion. An alternative approach, which is similar to those used for flood and wind hazard assessments, has been proposed. ?? 2011 ASCE.

  11. Seismic influence in the Quaternary uplift of the Central Chile coastal margin, preliminary results.

    Science.gov (United States)

    Valdivia, D.; del Valle, F.; Marquardt, C.; Elgueta, S.

    2017-12-01

    In order to quantify the influence of NW striking potentially seismogenic normal faults over the longitudinal variation of the Central Chile Coastal margin uplift, we measured Quaternary marine terraces, which represent the tectonic uplift of the coastal margin. Movement in margin oblique normal faults occurs by co-seismic extension of major subduction earthquakes and has occurred in the Pichilemu fault, generating a 7.0 Mw earthquake after the 2010 8.8 Mw Maule earthquake.The coastal area between 32° and 34° S was selected due to the presence of a well-preserved sequence of 2 to 5 Quaternary marine terraces. In particular, the margin oblique normal NW-trending, SW-dipping Laguna Verde fault, south of Valparaiso (33° S) puts in contact contrasting morphologies: to the south, a flat coast with wide marine terraces is carved in both, Jurassic plutonic rocks and Neogene semi-consolidated marine sediments; to the north, a steeper scarp with narrower marine terraces, over 120 m above the corresponding ones in the southern coast, is carved in Jurassic plutonic rocks.We have collected over 6 months microseimic data, providing information on seismic activity and underground geometry of the Laguna Verde fault. We collected ca. 100 systematic measurements of fringes at the base of paleo coastal scarps through field mapping and a 5 m digital elevation model. These fringes mark the maximum sea level during the terrace's carving.The heights of these fringes range between 0 and 250 masl. We estimate a 0.7 mm/yr slip rate for the Laguna Verde fault based on the height difference between corresponding terraces north- and southward, with an average uplift rate of 0.3 mm/yr for the whole area.NW striking normal faults, besides representing a potential seismic threat to the near population on one of the most densely populated areas of Chile, heavily controls the spatial variation of the coastal margin uplift. In Laguna Verde, the uplift rate differs more than three times northward

  12. Magmatic development of the outer Vøring margin from seismic data

    Science.gov (United States)

    Breivik, Asbjørn; Faleide, Jan Inge; Mjelde, Rolf; Flueh, Ernst; Murai, Yoshio

    2014-09-01

    The Vøring Plateau off mid-Norway is a volcanic passive margin, located north of the East Jan Mayen Fracture Zone (EJMFZ). Large volumes of magmatic rocks were emplaced during Early Eocene margin formation. In 2003, an ocean bottom seismometer survey was acquired over the margin. One profile crosses from the Vøring Plateau to the Vøring Spur, a bathymetric high north of the EJMFZ. The P wave data were ray traced into a 2-D crustal velocity model. The velocity structure of the Vøring Spur indicates up to 15 km igneous crustal thickness. Magmatic processes can be estimated by comparing seismic velocity (VP) with igneous thickness (H). This and two other profiles show a positive H-VP correlation at the Vøring Plateau, consistent with elevated mantle temperature at breakup. However, during the first 2 Ma magma production was augmented by a secondary process, possibly small-scale convection. From ˜51.5 Ma excess melting may be caused by elevated mantle temperature alone. Seismic stratigraphy around the Vøring Spur shows that it was created by at least two uplift events, with the main episode close to the Miocene/Pliocene boundary. Low H-VP correlation of the spur is consistent with renewed igneous growth by constant, moderate-degree mantle melting, not related to the breakup magmatism. The admittance function between bathymetry and free-air gravity shows that the high is near local isostatic equilibrium, precluding that compressional flexure at the EJMFZ uplifted the high. We find a proposed Eocene triple junction model for the margin to be inconsistent with observations.

  13. Seismic isolation - efficient procedure for seismic response assessement

    International Nuclear Information System (INIS)

    Zamfir, M. A.; Androne, M.

    2016-01-01

    The aim of this analysis is to reduce the dynamic response of a structure. The seismic isolation solution must take into consideration the specific site ground motion. In this paper will be presented results obtained by applying the seismic isolation method. Based on the obtained results, important conclusions can be outlined: the seismic isolation device has the ability to reduce seismic acceleration of the seismic isolated structure to values that no longer present a danger to people and environment; the seismic isolation solution is limiting devices deformations to safety values for ensuring structural integrity and stability of the entire system; the effective seismic energy dissipation and with no side effects both for the seismic isolated building and for the devices used, and the return to the initial position before earthquake occurence are obtained with acceptable permanent displacement. (authors)

  14. Deep seismic studies of conjugate profiles from the Nova Scotia - Moroccan and the Liguro-Provencal margin pairs

    Science.gov (United States)

    Klingelhoefer, F.; Biari, Y.; Sahabi, M.; Aslanian, D.; Philippe, S.; Schnabel, M.; Moulin, M.; Louden, K. E.; Funck, T.; Reichert, C. J.

    2014-12-01

    The structure of conjugate passive margins provides information about rifting styles, opening of an ocean and formation of it's associated sedimentary basins. In order to distinguish between tectonic inheritance and structures directly related to rifting of passive margins conjugate profiles have to be acquired on margins on diverse locations and different ages. In this study we use new and existing reflection and wide-angle seismic data from two margin pairs, the 200 Ma year old Nova-Scotia - Morocco margin pair and the only 20 Ma Gulf of Lions - Sardinia margin pair. On both margin pairs wide-angle seismic data combined with reflection seismic data were acquired on conjugate profiles on sea and extended on land. Forward modelling of the deep crustal structure along the four transects indicates that a high velocity zone (HVZ) (> 7.2 km/s) is present at the base of the lower crust on all four margins along the ocean-continental transition zone (OCT). This may represent either exhumed upper mantle material or injection of upper mantle material into proto-oceanic crust at the onset of sea-floor spreading. However the width of the HVZ might strongly differ between conjugates, which may be the result of tectonic inheritance, for example the presence of ancient subduction zones or orogens. Both margin pairs show a similar unthinned continental crustal thickness. Crustal thinning and upper-to-lower crustal thickness vary between margin pairs, but remain nearly symmetric on conjugate profiles and might therefore depend on the structure and mechanical properties of the original continental crust. For the Mediterranean margin pair, the oceanic crust is similar on both sides, with a thickness of only 4-5 km. For the Atlantic margin pair, oceanic crustal thickness is higher on the Moroccan Margin, a fact that can be explained by either asymmetric spreading or by the volcanic underplating, possibly originating from the Canary Hot Spot.

  15. Probabilistic Seismic Hazard Assessment for Iraq

    Energy Technology Data Exchange (ETDEWEB)

    Onur, Tuna [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gok, Rengin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Abdulnaby, Wathiq [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shakir, Ammar M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mahdi, Hanan [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Numan, Nazar M.S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Al-Shukri, Haydar [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chlaib, Hussein K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ameen, Taher H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Abd, Najah A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-05-06

    Probabilistic Seismic Hazard Assessments (PSHA) form the basis for most contemporary seismic provisions in building codes around the world. The current building code of Iraq was published in 1997. An update to this edition is in the process of being released. However, there are no national PSHA studies in Iraq for the new building code to refer to for seismic loading in terms of spectral accelerations. As an interim solution, the new draft building code was considering to refer to PSHA results produced in the late 1990s as part of the Global Seismic Hazard Assessment Program (GSHAP; Giardini et al., 1999). However these results are: a) more than 15 years outdated, b) PGA-based only, necessitating rough conversion factors to calculate spectral accelerations at 0.3s and 1.0s for seismic design, and c) at a probability level of 10% chance of exceedance in 50 years, not the 2% that the building code requires. Hence there is a pressing need for a new, updated PSHA for Iraq.

  16. Seismic Safety Margins Research Program. Phase 1. Project V. Structural sub-system response: subsystem response review

    International Nuclear Information System (INIS)

    Fogelquist, J.; Kaul, M.K.; Koppe, R.; Tagart, S.W. Jr.; Thailer, H.; Uffer, R.

    1980-03-01

    This project is directed toward a portion of the Seismic Safety Margins Research Program which includes one link in the seismic methodology chain. The link addressed here is the structural subsystem dynamic response which consists of those components and systems whose behavior is often determined decoupled from the major structural response. Typically the mathematical model utilized for the major structural response will include only the mass effects of the subsystem and the main model is used to produce the support motion inputs for subsystem seismic qualification. The main questions addressed in this report have to do with the seismic response uncertainty of safety-related components or equipment whose seismic qualification is performed by (a) analysis, (b) tests, or (c) combinations of analysis and tests, and where the seismic input is assumed to have no uncertainty

  17. SHC, Seismic Hazard Assessment for Eastern US

    International Nuclear Information System (INIS)

    Savy, J.; Davis, B.

    2001-01-01

    1 - Description of program or function: SHC was developed as part of the Eastern United States (EUS) Seismic Hazard Characterization (SHC) Project to design an SHC methodology for the region east of the Rocky Mountains in a form suitable for probabilistic risk assessment and to apply that methodology to 69 site locations, some of them with local soil conditions. The method developed uses expert opinions to obtain the input to the analysis. SHC contains four modules which calculate the seismic hazard at a site located in a region of diffuse seismicity, where the seismicity is modeled by area sources. SHC integrates the opinions of 11 seismicity and five ground-motion experts. The PRDS model generates the discrete probability density function of the distances to the site for the various seismic source zones. These probability distributions are used by the COMAP module to generate the set of all alternative maps and the discrete probability density of the seismic zonation maps for each expert. The third module, ALEAS, uses these maps and their weights to calculate the best estimate and constant percentile hazard distribution resulting from the choice of a given seismicity expert for all ground-motion experts. This module can be used alone to perform a seismic hazard analysis as well as in conjunction with the other modules. The fourth module, COMB, combines the best- estimate and constant-percentile hazard over all seismicity experts, using the set of weights calculated by ALEAS, to produce the final probability distribution of the hazard for the site under consideration so that the hazard analysis can be performed for any location in the EUS. Local geological-site characteristics are incorporated in a generic fashion, and the data are developed in a generic manner. 2 - Method of solution: SHC uses a seismic-source approach utilizing statistical and geological evidence to define geographical regions with homogeneous Poisson activity throughout the zone, described by a

  18. Seismic investigation on the Littoral Faults Zone in the northern continental margin of South China Sea

    Science.gov (United States)

    Sun, J.; Xu, H.; Xia, S.; Cao, J.; Wan, K.

    2017-12-01

    The continental margin of the northern South China Sea (SCS) had experienced continuous evolution from an active continental margin in the late Mesozoic to a passive continental margin in the Cenozoic. The 1200km-long Littoral Faults Zone (LFZ) off the mainland South China was suggested to represent one of the sub-plate boundaries and play a key role during the evolution. Besides, four devastating earthquakes with magnitude over 7 and another 11 destructive events with M>6 were documented to have occurred along the LFZ. However, its approximity to the shoreline, the shallow water depth, and the heavy fishing activities make it hard to conduct a marine seismic investigation. As a result, understandings about the LFZ before 2000 were relatively poor and mostly descriptive. After two experiments of joint onshore-offshore wide-angle seismic surveys in the 1st decade of this century, several cruses aiming to unveil the deep structure of the LFZ were performed in the past few years, with five joint onshore-offshore wide-angle seismic survey profiles completed. Each of these profiles is perpendicular to the shoreline, with four to five seismometers of campaign mode deployed on the landside and over ten Ocean Bottom Seismometers (OBSs) spacing at 20km deployed on the seaside. Meanwhile, multi-channel seismic (MCS) data along these profiles were obtained simultaneously. Based on these data, velocity models from both forward modeling and inversion were obtained. According to these models, the LFZ was imaged to be a low-velocity fractured zone dipping to the SSE-SE at a high-angle and cutting through the thinned continental crust at some locations. Width of the fractured zone varies from 6km to more than 10km from site to site. With these results, it is suggested that the LFZ accommodates the stresses from both the east side, where the Eurasia/Philippine Sea plate converging and mountain building is ongoing, and the west side, where a strike-slip between the Indochina

  19. Major structural response methods used in the seismic safety margins research program

    International Nuclear Information System (INIS)

    Chou, C.K.; Lo, T.; Vagliente, V.

    1979-01-01

    In order to evaluate the conservatisms in present nuclear power plant seismic safety requirements, a probabilistic based systems model is being developed. This model will also be used to develop improved requirements. In Phase I of the Seismic Safety Margins Research Program (SSMRP), this methodology will be developed for a specific nuclear power plant and used to perform probabilistic sensitivity studies to gain engineering insights into seismic safety requirements. Random variables in the structural response analysis area, or parameters which cause uncertainty in the response, are discussed and classified into three categories; i.e., material properties, structural dynamic characteristics and related modeling techniques, and analytical methods. The sensitivity studies are grouped into two categories; deterministic and probabilistic. In a system analysis, transfer functions in simple form are needed since there are too many responses which have to be calculated in a Monte Carlo simulation to use the usual straightforward calculation approach. Therefore, the development of these simple transfer functions is one of the important tasks in SSMRP. Simplified as well as classical transfer functions are discussed

  20. Seismic Risk Assessment for the Kyrgyz Republic

    Science.gov (United States)

    Pittore, Massimiliano; Sousa, Luis; Grant, Damian; Fleming, Kevin; Parolai, Stefano; Fourniadis, Yannis; Free, Matthew; Moldobekov, Bolot; Takeuchi, Ko

    2017-04-01

    The Kyrgyz Republic is one of the most socially and economically dynamic countries in Central Asia, and one of the most endangered by earthquake hazard in the region. In order to support the government of the Kyrgyz Republic in the development of a country-level Disaster Risk Reduction strategy, a comprehensive seismic risk study has been developed with the support of the World Bank. As part of this project, state-of-the-art hazard, exposure and vulnerability models have been developed and combined into the assessment of direct physical and economic risk on residential, educational and transportation infrastructure. The seismic hazard has been modelled with three different approaches, in order to provide a comprehensive overview of the possible consequences. A probabilistic seismic hazard assessment (PSHA) approach has been used to quantitatively evaluate the distribution of expected ground shaking intensity, as constrained by the compiled earthquake catalogue and associated seismic source model. A set of specific seismic scenarios based on events generated from known fault systems have been also considered, in order to provide insight on the expected consequences in case of strong events in proximity of densely inhabited areas. Furthermore, long-span catalogues of events have been generated stochastically and employed in the probabilistic analysis of expected losses over the territory of the Kyrgyz Republic. Damage and risk estimates have been computed by using an exposure model recently developed for the country, combined with the assignment of suitable fragility/vulnerability models. The risk estimation has been carried out with spatial aggregation at the district (rayon) level. The obtained results confirm the high level of seismic risk throughout the country, also pinpointing the location of several risk hotspots, particularly in the southern districts, in correspondence with the Ferghana valley. The outcome of this project will further support the local

  1. Probabilistic seismic hazard assessment of NW and central ...

    Indian Academy of Sciences (India)

    The Himalayan region has undergone significant development and to ensure safe and secure progress in such a seismically vulnerable region there is a need for hazard assessment. For seismic hazard assessment, it is important to assess the quality, consistency, and homogeneity of the seismicity data collected from ...

  2. Direct seismic detection of gas hydrates using multi-component seismology : a case study from the mid-Norwegian margin

    Energy Technology Data Exchange (ETDEWEB)

    Bunz, S.; Mienert, J. [Tromso Univ., Tromso (Norway). Dept. of Geology; Chand, S. [Norwegian Geological Survey, Trondheim (Norway)

    2008-07-01

    Gas hydrates are important as a possible future energy resource, in submarine landsliding and in global climate change as they contain more carbon than any other global reservoir and are plentiful on continental margins worldwide. It is therefore necessary to identify and map the distribution of gas hydrates in a fast and basin-wide approach. Information about the distribution of gas hydrates can be obtained using multi-component seismology. In the marine environment shear waves (S-waves) can be generated by conversion from a downward-propagating compressional wave (P-wave) upon reflection at a sedimentary interface. The upward-propagating S-wave can be recorded at the ocean floor using vertical and horizontal geophones. On the mid-Norwegian margin, a combined analysis of the independently obtained parameters, P-wave velocity and Vp/Vs-ratio, of ocean-bottom cable data enables the direct detection of gas hydrates with higher certainty and assessment of their grain-scale distribution and its controlling parameters. In order to directly image gas hydrates and to directly assess their grain-scale distribution, a model was developed to evaluate the distribution of the ratio of P- and S-wave velocities, Vp/Vs, along the ocean-bottom cable line. The study also evaluated possible controlling mechanisms for the distribution of gas hydrates. The paper provided detailed information on the distribution of gas hydrates and gas within the sediments through analyses of seismic velocities, obtained from multi-channel or ocean-bottom seismic data. It was concluded that gas hydrates are distributed both with and without affecting the shear strength of the sediments. 13 refs., 6 figs.

  3. Deep crustal structure of the northeastern margin of the Arabian plate from seismic and gravity data

    Science.gov (United States)

    Pilia, Simone; Ali, Mohammed; Watts, Anthony; Keats, Brook; Searle, Mike

    2017-04-01

    The United Arab Emirates-Oman mountains constitute a 700 km long, 50 km wide compressional orogenic belt that developed during the Cainozoic on an underlying extensional Tethyan rifted margin. It contains the world's largest and best-exposed thrust sheet of oceanic crust and upper mantle (Semail Ophiolite), which was obducted onto the Arabian rifted continental margin during the Late Cretaceous. Although the shallow structure of the UAE-Oman mountain belt is reasonably well known through the exploitation of a diverse range of techniques, information on deeper structure remains little. Moreover, the mechanisms by which dense oceanic crustal and mantle rocks are emplaced onto less dense and more buoyant continental crust are still controversial and remain poorly understood. The focus here is on an active-source seismic and gravity E-W transect extending from the UAE-mountain belt to the offshore. Seismic refraction data were acquired using the survey ship M/V Hawk Explorer, which was equipped with a large-volume airgun array (7060 cubic inches, 116 liters). About 400 air gun shots at 50-second time interval were recorded on land by eight broadband seismometers. In addition, reflection data were acquired at 20 seconds interval and recorded by a 5-km-long multichannel streamer. Results presented here include an approximately 85 km long (stretching about 35 km onshore and 50 km offshore) P-wave velocity crustal profile derived by a combination of forward modelling and inversion of both diving and reflected wave traveltimes using RAYINVR software. We employ a new robust algorithm based on a Monte Carlo approach (VMONTECARLO) to address the velocity model uncertainties. We find ophiolite seismic velocities of about 5.5 km/s and a thick sedimentary package in the offshore. Furthermore, the velocity model reveals a highly stretched crust with the Moho discontinuity lying at about 20 km. A prestack depth-migrated profile (about 50 km long) coincident with the offshore part

  4. Crustal structure across the Møre margin, mid-Norway, from wide-angle seismic and gravity data

    DEFF Research Database (Denmark)

    Kvarven, Trond; Ebbing, Jörg; Mjelde, R.

    2014-01-01

    The Møre Margin in the NE Atlantic represents a dominantly passive margin with an unusual abrupt transition from alpine morphology onshore to a deep sedimentary basin offshore. In order to study this transition in detail, three ocean bottom seismometer profiles with deep seismic reflection and re...... by the Jan Mayen Lineament, suggesting that the lineament represents a pre-Caledonian structural feature in the basement....

  5. Seismic assessment and upgrading of Paks nuclear power plant

    International Nuclear Information System (INIS)

    Tamas, K.

    2001-01-01

    A comprehensive programme for seismic assessment and upgrading is currently in progress at Hungary's Paks NPP. The re-evaluation of the site seismic hazard had been already completed. The technology of safe shut down and heat removal is established and the systems and structures relevant for seismic safety are identified. A seismic instrumentation is installed. The pre-earthquake preparedness and post-earthquake actions are elaborated. The methods for seismic capacity assessment are selected. The seismic capacity evaluation and the design of upgrading measures are currently in progress. The easy to perform upgrading covering the most urgent measures had been already performed. (author)

  6. Tectonic Inversion Along the Algerian and Ligurian Margins: On the Insight Provided By Latest Seismic Processing Techniques Applied to Recent and Vintage 2D Offshore Multichannel Seismic Data

    Science.gov (United States)

    Schenini, L.; Beslier, M. O.; Sage, F.; Badji, R.; Galibert, P. Y.; Lepretre, A.; Dessa, J. X.; Aidi, C.; Watremez, L.

    2014-12-01

    Recent studies on the Algerian and the North-Ligurian margins in the Western Mediterranean have evidenced inversion-related superficial structures, such as folds and asymmetric sedimentary perched basins whose geometry hints at deep compressive structures dipping towards the continent. Deep seismic imaging of these margins is difficult due to steep slope and superficial multiples, and, in the Mediterranean context, to the highly diffractive Messinian evaporitic series in the basin. During the Algerian-French SPIRAL survey (2009, R/V Atalante), 2D marine multi-channel seismic (MCS) reflection data were collected along the Algerian Margin using a 4.5 km, 360 channel digital streamer and a 3040 cu. in. air-gun array. An advanced processing workflow has been laid out using Geocluster CGG software, which includes noise attenuation, 2D SRME multiple attenuation, surface consistent deconvolution, Kirchhoff pre-stack time migration. This processing produces satisfactory seismic images of the whole sedimentary cover, and of southward dipping reflectors in the acoustic basement along the central part of the margin offshore Great Kabylia, that are interpreted as inversion-related blind thrusts as part of flat-ramp systems. We applied this successful processing workflow to old 2D marine MCS data acquired on the North-Ligurian Margin (Malis survey, 1995, R/V Le Nadir), using a 2.5 km, 96 channel streamer and a 1140 cu. in. air-gun array. Particular attention was paid to multiple attenuation in adapting our workflow. The resulting reprocessed seismic images, interpreted with a coincident velocity model obtained by wide-angle data tomography, provide (1) enhanced imaging of the sedimentary cover down to the top of the acoustic basement, including the base of the Messinian evaporites and the sub-salt Miocene series, which appear to be tectonized as far as in the mid-basin, and (2) new evidence of deep crustal structures in the margin which the initial processing had failed to

  7. Crustal structure of the North Iberian continental margin from seismic refraction/wide-angle reflection profiles

    Science.gov (United States)

    Ruiz, M.; Díaz, J.; Pedreira, D.; Gallart, J.; Pulgar, J. A.

    2017-10-01

    The structure and geodynamics of the southern margin of the Bay of Biscay have been investigated from a set of 11 multichannel seismic reflection profiles, recorded also at wide angle offsets in an onshore-offshore network of 24 OBS/OBH and 46 land sites. This contribution focuses on the analysis of the wide-angle reflection/refraction data along representative profiles. The results document strong lateral variations of the crustal structure along the margin and provide an extensive test of the crustal models previously proposed for the northern part of the Iberian Peninsula. Offshore, the crust has a typical continental structure in the eastern tip of the bay, which disappears smoothly towards the NW to reach crustal thickness close to 10 km at the edge of the studied area ( 45°N, 6°W). The analysis of the velocity-depth profiles, altogether with additional information provided by the multichannel seismic data and magnetic surveys, led to the conclusion that the crust in this part of the bay should be interpreted as transitional from continental to oceanic. Typical oceanic crust has not been imaged in the investigated area. Onshore, the new results are in good agreement with previous results and document the indentation of the Bay of Biscay crust into the Iberian crust, forcing its subduction to the North. The interpreted profiles show that the extent of the southward indentation is not uniform, with an Alpine root less developed in the central and western sector of the Basque-Cantabrian Basin. N-S to NE-SW transfer structures seem to control those variations in the indentation degree.

  8. Mine aftershocks and implications for seismic hazard assessment

    CSIR Research Space (South Africa)

    Kgarume, T

    2010-11-01

    Full Text Available A methodology of assessing the seismic hazard associated with aftershocks is developed by performing statistical and deterministic analysis of seismic data from two South African deep-level gold mines. A method employing stacking of aftershocks...

  9. Seismic assessment of existing nuclear chemical plants

    International Nuclear Information System (INIS)

    Merriman, P.A.

    1997-01-01

    This paper outlines the generic approach to the seismic assessment of existing structures. It describes the role of the safety case in determining the studies carried out by the functional departments on individual projects. There is an emphasis on the role of existing information and material tests to provide realistic properties for analysis to account for possible degradation effects. Finally, a case study of a concrete containment cell is shown to illustrate the approach. (author)

  10. Insights into crustal structure of the Eastern North American Margin from community multichannel seismic and potential field data

    Science.gov (United States)

    Davis, J. K.; Becel, A.; Shillington, D. J.; Buck, W. R.

    2017-12-01

    In the fall of 2014, the R/V Marcus Langseth collected gravity, magnetic, and reflection seismic data as part of the Eastern North American Margin Community Seismic Experiment. The dataset covers a 500 km wide section of the Mid-Atlantic passive margin offshore North Carolina, which formed after the Mesozoic breakup of the supercontinent Pangaea. Using these seismic and potential field data, we present observations and interpretations along two cross margin and one along-margin profiles. Analyses and interpretations are conducted using pre-stack depth migrated reflection seismic profiles in conjunction with forward modeling of shipboard gravity and magnetic anomalies. Preliminary interpretations of the data reveal variations in basement character and structure across the entire transition between continental and oceanic domains. These interpretations help provide insight into the origin and nature of the prominent East Coast and Blake Spur magnetic anomalies, as well as the Inner Magnetic Quiet Zone which occupies the domain between the anomalies. Collectively, these observations can aid in deciphering the rift-to-drift transition during the breakup of North America and West Africa and formation of the Central Atlantic.

  11. Differences in safety margins between nuclear and conventional design standards with regards to seismic hazard definition and design criteria

    International Nuclear Information System (INIS)

    Elgohary, M.; Saudy, A.; Orbovic, N.; Dejan, D.

    2006-01-01

    With the surging interest in new build nuclear all over the world and a permanent interest in earthquake resistance of nuclear plants, there is a need to quantify the safety margins in nuclear buildings design in comparison to conventional buildings in order to increase the public confidence in the safety of nuclear power plants. Nuclear (CAN3-N289 series) and conventional (NBCC 2005) seismic standards have different approaches regarding the design of civil structures. The origin of the differences lays in the safety philosophy behind the seismic nuclear and conventional standards. Conventional seismic codes contain the minimal requirement destined primarily to safeguard against major structural failure and loss of life. It doesn't limit damage to a certain acceptable degree or maintain function. Nuclear seismic code requires that structures, systems and components important to safety, withstand the effects of earthquakes. The requirement states that for equipment important to safety, both integrity and functionality should be ascertained. The seismic hazard is generally defined on the basis of the annual probability of exceedence (return period). There is a major difference on the return period and the confidence level for design earthquakes between the conventional and the nuclear seismic standards. The seismic design criteria of conventional structures are based on the use of Force Modification Factors to take into account the energy dissipation by incursion in non-elastic domain and the reserve of strength. The use of such factors to lower intentionally the seismic input is consistent with the safety philosophy of the conventional seismic standard which is the 'non collapse' rather than the integrity and/or the operability of the structures or components. Nuclear seismic standard requires that the structure remain in the elastic domain; energy dissipation by incursion in non-elastic domain is not allowed for design basis earthquake conditions. This is

  12. Seismic risk assessment of Navarre (Northern Spain)

    Science.gov (United States)

    Gaspar-Escribano, J. M.; Rivas-Medina, A.; García Rodríguez, M. J.; Benito, B.; Tsige, M.; Martínez-Díaz, J. J.; Murphy, P.

    2009-04-01

    The RISNA project, financed by the Emergency Agency of Navarre (Northern Spain), aims at assessing the seismic risk of the entire region. The final goal of the project is the definition of emergency plans for future earthquakes. With this purpose, four main topics are covered: seismic hazard characterization, geotechnical classification, vulnerability assessment and damage estimation to structures and exposed population. A geographic information system is used to integrate, analyze and represent all information colleted in the different phases of the study. Expected ground motions on rock conditions with a 90% probability of non-exceedance in an exposure time of 50 years are determined following a Probabilistic Seismic Hazard Assessment (PSHA) methodology that includes a logic tree with different ground motion and source zoning models. As the region under study is located in the boundary between Spain and France, an effort is required to collect and homogenise seismological data from different national and regional agencies. A new homogenised seismic catalogue, merging data from Spanish, French, Catalonian and international agencies and establishing correlations between different magnitude scales, is developed. In addition, a new seismic zoning model focused on the study area is proposed. Results show that the highest ground motions on rock conditions are expected in the northeastern part of the region, decreasing southwards. Seismic hazard can be expressed as low-to-moderate. A geotechnical classification of the entire region is developed based on surface geology, available borehole data and morphotectonic constraints. Frequency-dependent amplification factors, consistent with code values, are proposed. The northern and southern parts of the region are characterized by stiff and soft soils respectively, being the softest soils located along river valleys. Seismic hazard maps including soil effects are obtained by applying these factors to the seismic hazard maps

  13. Seismic hazard assessment; Valutazione della pericolosita` sismica

    Energy Technology Data Exchange (ETDEWEB)

    Paciello, A. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dip. Ambiente

    1998-12-31

    This paper presents a brief summary of the most commonly used methodologies for seismic hazard assessment. The interest is focused on the probabilistic approach, which can take into account the uncertainties of input data and provides results better comparable with those obtained from hazard analyses of other natural phenomena. Calculation methods, input data and treatment of variability are examined. Some examples of probabilistic seismic hazard maps are moreover presented. [Italiano] Questo lavoro presenta un breve sommario delle piu` comuni metodologie utilizzate per la valutazione della pericolosita` sismica di un sito. Una particolare attenzione e` rivolta all`approccio probabilistico, che permette di tener conto delle incertezze legate ai dati iniziali e fornisce risultati piu` facilmente confrontabili con quelli ottenuti da analisi di pericolosita` di altri fenomeni naturali. Vengono presi in esame i metodi di calcolo, i dati di base e il trattamento delle incertezze. Vengono inoltre presentati alcuni esempi di carte di pericolosita` sismica di tipo probabilistico.

  14. Northeastern Brazilian margin: Regional tectonic evolution based on integrated analysis of seismic reflection and potential field data and modelling

    Science.gov (United States)

    Blaich, Olav A.; Tsikalas, Filippos; Faleide, Jan Inge

    2008-10-01

    Integration of regional seismic reflection and potential field data along the northeastern Brazilian margin, complemented by crustal-scale gravity modelling, is used to reveal and illustrate onshore-offshore crustal structure correlation, the character of the continent-ocean boundary, and the relationship of crustal structure to regional variation of potential field anomalies. The study reveals distinct along-margin structural and magmatic changes that are spatially related to a number of conjugate Brazil-West Africa transfer systems, governing the margin segmentation and evolution. Several conceptual tectonic models are invoked to explain the structural evolution of the different margin segments in a conjugate margin context. Furthermore, the constructed transects, the observed and modelled Moho relief, and the potential field anomalies indicate that the Recôncavo, Tucano and Jatobá rift system may reflect a polyphase deformation rifting-mode associated with a complex time-dependent thermal structure of the lithosphere. The constructed transects and available seismic reflection profiles, indicate that the northern part of the study area lacks major breakup-related magmatic activity, suggesting a rifted non-volcanic margin affinity. In contrast, the southern part of the study area is characterized by abrupt crustal thinning and evidence for breakup magmatic activity, suggesting that this region evolved, partially, with a rifted volcanic margin affinity and character.

  15. Assessment of tsunami hazard to the U.S. Atlantic margin

    Science.gov (United States)

    ten Brink, Uri S.; Chaytor, Jason; Geist, Eric L.; Brothers, Daniel S.; Andrews, Brian D.

    2014-01-01

    Tsunami hazard is a very low-probability, but potentially high-risk natural hazard, posing unique challenges to scientists and policy makers trying to mitigate its impacts. These challenges are illustrated in this assessment of tsunami hazard to the U.S. Atlantic margin. Seismic activity along the U.S. Atlantic margin in general is low, and confirmed paleo-tsunami deposits have not yet been found, suggesting a very low rate of hazard. However, the devastating 1929 Grand Banks tsunami along the Atlantic margin of Canada shows that these events continue to occur. Densely populated areas, extensive industrial and port facilities, and the presence of ten nuclear power plants along the coast, make this region highly vulnerable to flooding by tsunamis and therefore even low-probability events need to be evaluated.

  16. Rippability Assessment of Weathered Sedimentary Rock Mass using Seismic Refraction Methods

    Science.gov (United States)

    Ismail, M. A. M.; Kumar, N. S.; Abidin, M. H. Z.; Madun, A.

    2018-04-01

    Rippability or ease of excavation in sedimentary rocks is a significant aspect of the preliminary work of any civil engineering project. Rippability assessment was performed in this study to select an available ripping machine to rip off earth materials using the seismic velocity chart provided by Caterpillar. The research area is located at the proposed construction site for the development of a water reservoir and related infrastructure in Kampus Pauh Putra, Universiti Malaysia Perlis. The research was aimed at obtaining seismic velocity, P-wave (Vp) using a seismic refraction method to produce a 2D tomography model. A 2D seismic model was used to delineate the layers into the velocity profile. The conventional geotechnical method of using a borehole was integrated with the seismic velocity method to provide appropriate correlation. The correlated data can be used to categorize machineries for excavation activities based on the available systematic analysis procedure to predict rock rippability. The seismic velocity profile obtained was used to interpret rock layers within the ranges labelled as rippable, marginal, and non-rippable. Based on the seismic velocity method the site can be classified into loose sand stone to moderately weathered rock. Laboratory test results shows that the site’s rock material falls between low strength and high strength. Results suggest that Caterpillar’s smallest ripper, namely, D8R, can successfully excavate materials based on the test results integration from seismic velocity method and laboratory test.

  17. Seismic safety margins research program. Phase I final report - Major structure response (Project IV)

    International Nuclear Information System (INIS)

    Benda, B.J.; Johnson, J.J.; Lo, T.Y.

    1981-08-01

    The primary task of the Major Structure Response Project within the Seismic Safety Margins Research Program (SSMRP) was to develop detailed finite element models of the Zion Nuclear Power Plant's containment building and auxiliary-fuel-turbine (AFT) complex. The resulting models served as input to the seismic methodology analysis chain. The containment shell was modeled as a series of beam elements with the shear and bending characteristics of a circular cylindrical shell. Masses and rotary inertias were lumped at nodal points; thirteen modes were included in the analysis. The internal structure was modeled with three-dimensional finite elements, with masses again lumped at selected nodes; sixty modes were included in the analysis. The model of the AFT complex employed thin plate and shell elements to represent the concrete shear walls and floor diaphragms, and beam and truss elements to model the braced frames. Because of the size and complexity of the model, and the potentially large number of degrees of freedom, masses were lumped at a limited number of node points. These points were selected so as to minimize the effect of the discrete mass distribution on structural response. One hundred and thirteen modes were extracted. A second objective of Project IV was to investigate the effects of uncertainty and variability on structural response. To this end, four side studies were conducted. Three of them, briefly summarized in this volume, addressed themselves respectively to an investigation of sources of random variability in the dynamic response of nuclear power plant structures; formulation of a methodology for modeling and evaluating the effects of structural uncertainty on predicted modal characteristics of major nuclear power plant structures and substructures; and a preliminary evaluation of nonlinear responses in shear-wall structures. A fourth side study, reported in detail in this volume, quantified variations in dynamic characteristics and seismic

  18. Crustal structure of the southeast Greenland margin from joint refraction and reflection seismic tomography

    Science.gov (United States)

    Korenaga, J.; Holbrook, W. S.; Kent, G. M.; Kelemen, P. B.; Detrick, R. S.; Larsen, H.-C.; Hopper, J. R.; Dahl-Jensen, T.

    2000-09-01

    We present results from a combined multichannel seismic reflection (MCS) and wideangle onshore/offshore seismic experiment conducted in 1996 across the southeast Greenland continental margin. A new seismic tomographic method is developed to jointly invert refraction and reflection travel times for a two-dimensional velocity structure. We employ a hybrid ray-tracing scheme based on the graph method and the local ray-bending refinement to efficiently obtain an accurate forward solution, and we employ smoothing and optional damping constraints to regularize an iterative inversion. We invert 2318 Pg and 2078 PmP travel times to construct a compressional velocity model for the 350-km-long transect, and a long-wavelength structure with strong lateral heterogeneity is recovered, including (1) ˜30-km-thick, undeformed continental crust with a velocity of 6.0 to 7.0 km/s near the landward end, (2) 30- to 15-km-thick igneous crust within a 150-km-wide continent-ocean transition zone, and (3) 15- to 9-km-thick oceanic crust toward the seaward end. The thickness of the igneous upper crust characterized by a high-velocity gradient also varies from 6 km within the transition zone to ˜3 km seaward. The bottom half of the lower crust generally has a velocity higher than 7.0 km/s, reaching a maximum of 7.2 to 7.5 km/s at the Moho. A nonlinear Monte Carlo uncertainty analysis is performed to estimate the a posteriori model variance, showing that most velocity and depth nodes are well determined with one standard deviation of 0.05-0.10 km/s and 0.25-1.5 km, respectively. Despite significant variation in crustal thickness, the mean velocity of the igneous crust, which serves as a proxy for the bulk crustal composition, is surprisingly constant (˜7.0 km/s) along the transect. On the basis of a mantle melting model incorporating the effect of active mantle upwelling, this velocity-thickness relationship is used to constrain the mantle melting process during the breakup of Greenland

  19. Seismic characterization of fluid migration and Pockmarks in the Estremadura Spur, West Iberian Margin, Portugal

    Science.gov (United States)

    Duarte, Débora; Magalhães, Vitor Hugo; Terrinha, Pedro; Ribeiro, Carlos; Madureira, Pedro; Menezes Pinheiro, Luís; Benazzouz, Omar; Kim, Jung-Hyun; Duarte, Henrique

    2017-04-01

    Recently a field with more than 70 pockmarks was discovered in the NW region of the Estremadura Spur outer shelf (West Iberian margin), a trapezoidal promontory elongated in an east-west direction, between Cabo Carvoeiro and Cabo da Roca, extending until the Tore seamount. Pockmarks are the seabed culminations of fluid migration through the sedimentary column and their characteristic seabed morphologies correspond to cone-shaped circular or elliptical depressions. These features and the associated fluid escape process are the main objectives of this work. Here we characterize these structures to understand their structural and stratigraphic control based on: 1) Seismic processing and interpretation of the high resolution 2D single-channel sparker seismic dataset, 2) Bathymetric and Backscatter interpretation and 3) ROV direct observation of the seafloor. The analysis of the seismic profiles allowed the identification of six seismic units, disturbed by the migration and accumulation of fluids. The Estremadura Spur outer shelf has been affected by several episodes of fluid migration and fluid escape during the Pliocene-Quaternary that are expressed by a vast number of seabed and buried pockmarks. At present, the pockmarks are mainly inactive, as the seabed pockmarks are covered by recent sediments. The stacking of various pockmarks suggests a cyclical fluid flow activity that can possibly be the result of the eustatic sea level variations and the subsequent changes of the hydrostatic pressure. The origin of the seep fluids is still under debate but considering the low-sedimentation rate of the area and the low productivity a deep source for the fluids is most probable, possibly related with the Jurassic hydrocarbon system. It was concluded that the migration of fluids to the seabed occurred over the Pliocene-Quaternary in several episodes, as indicated by the buried pockmarks at different depths. Acknowledgements: This work was carried out in the framework of the PES

  20. Subsystem response determination for the US NRC Seismic Safety Margins Research Program

    International Nuclear Information System (INIS)

    Johnson, J.J.

    1979-01-01

    The initial portion of the task described deals with a definition of the state-of-the-art of seismic qualification methods for subsystems. Too facilitate treatment of this broad class of subsystems, three classifications have been identified: multiply supported subsystems (e.g., piping systems); mechanical components (e.g., valves, pumps, control rod drives, hydraulic systems, etc.); and electrical components (e.g., electrical control panels). Descriptions of the available analysis and/or testing techniques for the above classifications are sought. The results of this assessment will be applied to the development of structural subsystem transfer functions

  1. SSI sensitivity studies and model improvements for the US NRC Seismic Safety Margins Research Program. Rev. 1

    International Nuclear Information System (INIS)

    Johnson, J.J.; Maslenikov, O.R.; Benda, B.J.

    1984-10-01

    The Seismic Safety Margins Research Program (SSMRP) is a US NRC-funded program conducted by Lawrence Livermore National Laboratory. Its goal is to develop a complete fully coupled analysis procedure for estimating the risk of an earthquake-induced radioactive release from a commercial nuclear power plant. In Phase II of the SSMRP, the methodology was applied to the Zion nuclear power plant. Three topics in the SSI analysis of Zion were investigated and reported here - flexible foundation modeling, structure-to-structure interaction, and basemat uplift. The results of these investigations were incorporated in the SSMRP seismic risk analysis. 14 references, 51 figures, 13 tables

  2. Seismic risk assessment of a BWR: status report

    International Nuclear Information System (INIS)

    Chuang, T.Y.; Bernreuter, D.L.; Wells, J.E.; Johnson, J.J.

    1985-02-01

    The seismic risk methodology developed in the US NRC Seismic Safety Margins Research Program (SSMRP) was demonstrated by its application to the Zion nuclear power plant, a pressurized water reactor (PWR). A detailed model of Zion, including systems analysis models (initiating events, event trees, and fault trees), SSI and structure models, and piping models was developed and analyzed. The SSMRP methodology can equally be applied to a boiling water reactor (BWR). To demonstrate its applicability, to identify fundamental differences in seismic risk between a PWR and a BWR, and to provide a basis of comparison of seismic risk between a PWR and a BWR when analyzed with comparable methodology and assumptions, a seismic risk analysis is being performed on the LaSalle County Station nuclear power plant

  3. Value chain and marketing margins of cassava: An assessment of ...

    African Journals Online (AJOL)

    Value chain and marketing margins of cassava: An assessment of cassava marketing in ... African Journal of Food, Agriculture, Nutrition and Development ... Cassava is one of the emerging market oriented agricultural commodities with ...

  4. Development of a seismic damage assessment program for nuclear power plant structures

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Hyun Moo; Cho, Yang Heui; Shin, Hyun Mok [Seoul National Univ., Seoul (Korea, Republic of)] (and others)

    2001-12-15

    The most part of the nuclear power plants operating currently in Korea are more than 20 years old and obviously we cannot pretend that their original performance is actually maintained. In addition, earthquake occurrences show an increasing trend all over the world, and Korea can no more be considered as a zone safe from earthquake. Therefore, need is to guarantee the safety of these power plant structures against seismic accident, to decide to maintain them operational and to obtain data relative to maintenance/repair. Such objectives can be reached by damage assessment using inelastic seismic analysis considering aging degradation. It appears to be more important particularly for the structure enclosing the nuclear reactor that must absolutely protect against any radioactive leakage. Actually, the tendency of the technical world, led by the OECD/NEA, BNL in the United States, CEA in France and IAEA, is to develop researches or programs to assess the seismic safety considering aging degradation of operating nuclear power plants. Regard to the above-mentioned international technical trend, a technology to establish inelastic seismic analysis considering aging degradation so as to assess damage level and seismic safety margin appears to be necessary. Damage assessment and prediction system to grasp in real-time the actual seismic resistance capacity and damage level by 3-dimensional graphic representations are also required.

  5. Development of a seismic damage assessment program for nuclear power plant structures

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Hyun Moo; Cho, Ho Hyun; Cho, Yang Hui [Seoul National Univ., Seoul (Korea, Republic of)] (and others)

    2000-12-15

    Some of nuclear power plants operating currently in Korea have been passed about 20 years after construction. Moreover, in the case of KORI I the service year is over 20 years, so their abilities are different from initial abilities. Also, earthquake outbreak increase, our country is not safe area for earthquake. Therefore, need is to guarantee the safety of these power plant structures against seismic accident, to decide to maintain them operational and to obtain data relative to maintenance/repair. Such objectives can be reached by damage assessment using inelastic seismic analysis considering aging degradation. It appears to be more important particularly for the structure enclosing the nuclear reactor that must absolutely protect against any radioactive leakage. Actually, the tendency of the technical world, led by the OECD/NEA, BNL in the United States, CEA in France and IAEA, is to develop researches or programs to assess the seismic safety considering aging degradation of operating nuclear power plants. Regard to the above-mentioned international technical trend, a technology to establish inelastic seismic analysis considering aging degradation so as to assess damage level and seismic safety margin appears to be necessary. Damage assessment and prediction system to grasp in real-time the actual seismic resistance capacity and damage level by 3-dimensional graphic representations are also required.

  6. Application of Nonlinear Seismic Soil-Structure Interaction Analysis for Identification of Seismic Margins at Nuclear Power Plants

    International Nuclear Information System (INIS)

    Varma, Amit H.; Seo, Jungil; Coleman, Justin Leigh

    2015-01-01

    Seismic probabilistic risk assessment (SPRA) methods and approaches at nuclear power plants (NPP) were first developed in the 1970s and aspects of them have matured over time as they were applied and incrementally improved. SPRA provides information on risk and risk insights and allows for some accounting for uncertainty and variability. As a result, SPRA is now used as an important basis for risk-informed decision making for both new and operating NPPs in the US and in an increasing number of countries globally. SPRAs are intended to provide best estimates of the various combinations of structural and equipment failures that can lead to a seismic induced core damage event. However, in some instances the current SPRA approach contains large uncertainties, and potentially masks other important events (for instance, it was not the seismic motions that caused the Fukushima core melt events, but the tsunami ingress into the facility). INL has an advanced SPRA research and development (R&D) activity that will identify areas in the calculation process that contain significant uncertainties. One current area of focus is the use of nonlinear soil-structure interaction (NLSSI) analysis methods to accurately capture: 1) nonlinear soil behavior and 2) gapping and sliding between the NPP and soil. The goal of this study is to compare numerical NLSSI analysis results with recorded earthquake ground motions at Fukushima Daichii (Great Tohuku Earthquake) and evaluate the sources of nonlinearity contributing to the observed reduction in peak acceleration. Comparisons are made using recorded data in the free-field (soil column with no structural influence) and recorded data on the NPP basemat (in-structure response). Results presented in this study should identify areas of focus for future R&D activities with the goal of minimizing uncertainty in SPRA calculations. This is not a validation activity since there are too many sources of uncertainty that a numerical analysis would need

  7. Use of the t-distribution to construct seismic hazard curves for seismic probabilistic safety assessments

    Energy Technology Data Exchange (ETDEWEB)

    Yee, Eric [KEPCO International Nuclear Graduate School, Dept. of Nuclear Power Plant Engineering, Ulsan (Korea, Republic of)

    2017-03-15

    Seismic probabilistic safety assessments are used to help understand the impact potential seismic events can have on the operation of a nuclear power plant. An important component to seismic probabilistic safety assessment is the seismic hazard curve which shows the frequency of seismic events. However, these hazard curves are estimated assuming a normal distribution of the seismic events. This may not be a strong assumption given the number of recorded events at each source-to-site distance. The use of a normal distribution makes the calculations significantly easier but may underestimate or overestimate the more rare events, which is of concern to nuclear power plants. This paper shows a preliminary exploration into the effect of using a distribution that perhaps more represents the distribution of events, such as the t-distribution to describe data. The integration of a probability distribution with potentially larger tails basically pushes the hazard curves outward, suggesting a different range of frequencies for use in seismic probabilistic safety assessments. Therefore the use of a more realistic distribution results in an increase in the frequency calculations suggesting rare events are less rare than thought in terms of seismic probabilistic safety assessment. However, the opposite was observed with the ground motion prediction equation considered.

  8. Use of the t-distribution to construct seismic hazard curves for seismic probabilistic safety assessments

    International Nuclear Information System (INIS)

    Yee, Eric

    2017-01-01

    Seismic probabilistic safety assessments are used to help understand the impact potential seismic events can have on the operation of a nuclear power plant. An important component to seismic probabilistic safety assessment is the seismic hazard curve which shows the frequency of seismic events. However, these hazard curves are estimated assuming a normal distribution of the seismic events. This may not be a strong assumption given the number of recorded events at each source-to-site distance. The use of a normal distribution makes the calculations significantly easier but may underestimate or overestimate the more rare events, which is of concern to nuclear power plants. This paper shows a preliminary exploration into the effect of using a distribution that perhaps more represents the distribution of events, such as the t-distribution to describe data. The integration of a probability distribution with potentially larger tails basically pushes the hazard curves outward, suggesting a different range of frequencies for use in seismic probabilistic safety assessments. Therefore the use of a more realistic distribution results in an increase in the frequency calculations suggesting rare events are less rare than thought in terms of seismic probabilistic safety assessment. However, the opposite was observed with the ground motion prediction equation considered

  9. Long-term seismic observations along Myanmar-Sunda subduction margin: insights for 2004 M w > 9.0 earthquake

    Science.gov (United States)

    Khan, Prosanta Kumar; Banerjee, Jayashree; Shamim, Sk; Mohanty, Manoranjan

    2018-03-01

    The present study investigates the temporal variation of few seismic parameters between the Myanmar (Zone I), Andaman-Nicobar-Northwest Sumatra (Zone II), Southeast Sumatra-West Indonesia (Zone III) and East Indonesia (Zone IV) converging boundaries in reference to the generation of 26 December 2004 M w > 9.0 off-Sumatra mega-earthquake event. The four segments are distinguished based on tectonics parameters, distinct geological locations, great earthquake occurrences, and the Wadati-Benioff zone characteristics. Two important seismic parameters such as seismic energy and b values are computed over a time-window of 6-month period during the entire 1976-2013 period for these segments. The b values show a constant decrease in Zones II, III, and IV, whereas the Zone I does not show any such pattern prior to the 2004 mega-event. The release of seismic energy was also gradually decreasing in Zones II and III till the 2004 event, and little similar pattern was also noted in Zone IV. This distinct observation might be indicating that the stress accumulation was dominant near the Sumatra-Java area located towards southeast of Zone II and northwest of Zone III. The released strain energy during the 2004 event was subsequently migrated towards north, rupturing 1300 km of the boundary between the Northwest Sumatra and the North Andaman. The occurrence of 2004 mega-event was apparently concealed behind the long-term seismic quiescence existing near the Sumatra and Nicobar margin. A systematic study of the patterns of seismic energy release and b values, and the long-term observation of collective behaviour of the margin tectonics might have had given clues to the possibility of the 2004 mega-event.

  10. Marginal Assessment of Crowns by the Aid of Parallel Radiography

    Directory of Open Access Journals (Sweden)

    Farnaz Fattahi

    2015-03-01

    Full Text Available Introduction: Marginal adaptation is the most critical item in long-term prognosis of single crowns. This study aimed to assess the marginal quality as well asthe discrepancies in marginal integrity of some PFM single crowns of posterior teeth by employing parallel radiography in Shiraz Dental School, Shiraz, Iran. Methods: In this descriptive study, parallel radiographies were taken from 200 fabricated PFM single crowns of posterior teeth after cementation and before discharging the patient. To calculate the magnification of the images, a metallic sphere with the thickness of 4 mm was placed in the direction of the crown margin on the occlusal surface. Thereafter, the horizontal and vertical space between the crown margins, the margin of preparations and also the vertical space between the crown margin and the bone crest were measured by using digital radiological software. Results: Analysis of data by descriptive statistics revealed that 75.5% and 60% of the cases had more than the acceptable space (50µm in the vertical (130±20µm and horizontal (90±15µm dimensions, respectively. Moreover, 85% of patients were found to have either horizontal or vertical gap. In 77% of cases, the margins of crowns invaded the biologic width in the mesial and 70% in distal surfaces. Conclusion: Parallel radiography can be expedient in the stage of framework try-in to yield some important information that cannot be obtained by routine clinical evaluations and may improve the treatment prognosis

  11. Transparent Global Seismic Hazard and Risk Assessment

    Science.gov (United States)

    Smolka, Anselm; Schneider, John; Pinho, Rui; Crowley, Helen

    2013-04-01

    Vulnerability to earthquakes is increasing, yet advanced reliable risk assessment tools and data are inaccessible to most, despite being a critical basis for managing risk. Also, there are few, if any, global standards that allow us to compare risk between various locations. The Global Earthquake Model (GEM) is a unique collaborative effort that aims to provide organizations and individuals with tools and resources for transparent assessment of earthquake risk anywhere in the world. By pooling data, knowledge and people, GEM acts as an international forum for collaboration and exchange, and leverages the knowledge of leading experts for the benefit of society. Sharing of data and risk information, best practices, and approaches across the globe is key to assessing risk more effectively. Through global projects, open-source IT development and collaborations with more than 10 regions, leading experts are collaboratively developing unique global datasets, best practice, open tools and models for seismic hazard and risk assessment. Guided by the needs and experiences of governments, companies and citizens at large, they work in continuous interaction with the wider community. A continuously expanding public-private partnership constitutes the GEM Foundation, which drives the collaborative GEM effort. An integrated and holistic approach to risk is key to GEM's risk assessment platform, OpenQuake, that integrates all above-mentioned contributions and will become available towards the end of 2014. Stakeholders worldwide will be able to calculate, visualise and investigate earthquake risk, capture new data and to share their findings for joint learning. Homogenized information on hazard can be combined with data on exposure (buildings, population) and data on their vulnerability, for loss assessment around the globe. Furthermore, for a true integrated view of seismic risk, users can add social vulnerability and resilience indices to maps and estimate the costs and benefits

  12. Site response assessment using borehole seismic records

    Energy Technology Data Exchange (ETDEWEB)

    Park, Donghee; Chang, Chunjoong; Choi, Weonhack [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    In regions with high seismic activity, such as Japan, the Western United States and Taiwan, borehole seismometers installed deep underground are used to monitor seismic activity during the course of seismic wave propagation at various depths and to study the stress changes due to earthquakes and analyze the connection to fault movements. The Korea Meteorological Administration (KMA) and the Korea Institute of Geology and Mining (KIGAM) have installed and are operating borehole seismometers at a depth of 70∼100 meters for the precise determination of epicenters. Also, Korea Hydro and Nuclear Power Co., Ltd. (KHNP) has installed and is operating 2 borehole seismic stations near Weolseong area to observe at a depth of 140 meters seismic activities connected to fault activity. KHNP plans to operate in the second half of 2014 a borehole seismic station for depths less than 300 and 600 meters in order to study the seismic response characteristics in deep strata. As a basic study for analyzing ground motion response characteristics at depths of about 300 to 600 meters in connection with the deep geological disposal of spent nuclear fuel, the present study examined the background noise response characteristics of the borehole seismic station operated by KHNP. In order to analyze the depth-dependent impact of seismic waves at deeper depths than in Korea, seismic data collected by Japan's KIK-net seismic stations were used and the seismic wave characteristics analyzed by size and depth. In order to analyze the borehole seismic observation data from the seismic station operated by KHNP, this study analyzed the background noise characteristics by using a probability density function.

  13. Site response assessment using borehole seismic records

    International Nuclear Information System (INIS)

    Park, Donghee; Chang, Chunjoong; Choi, Weonhack

    2014-01-01

    In regions with high seismic activity, such as Japan, the Western United States and Taiwan, borehole seismometers installed deep underground are used to monitor seismic activity during the course of seismic wave propagation at various depths and to study the stress changes due to earthquakes and analyze the connection to fault movements. The Korea Meteorological Administration (KMA) and the Korea Institute of Geology and Mining (KIGAM) have installed and are operating borehole seismometers at a depth of 70∼100 meters for the precise determination of epicenters. Also, Korea Hydro and Nuclear Power Co., Ltd. (KHNP) has installed and is operating 2 borehole seismic stations near Weolseong area to observe at a depth of 140 meters seismic activities connected to fault activity. KHNP plans to operate in the second half of 2014 a borehole seismic station for depths less than 300 and 600 meters in order to study the seismic response characteristics in deep strata. As a basic study for analyzing ground motion response characteristics at depths of about 300 to 600 meters in connection with the deep geological disposal of spent nuclear fuel, the present study examined the background noise response characteristics of the borehole seismic station operated by KHNP. In order to analyze the depth-dependent impact of seismic waves at deeper depths than in Korea, seismic data collected by Japan's KIK-net seismic stations were used and the seismic wave characteristics analyzed by size and depth. In order to analyze the borehole seismic observation data from the seismic station operated by KHNP, this study analyzed the background noise characteristics by using a probability density function

  14. Seismic analysis of clinoform depositional sequences and shelf-margin trajectories in Lower Cretaceous (Albian) strata, Alaska North Slope

    Science.gov (United States)

    Houseknecht, D.W.; Bird, K.J.; Schenk, C.J.

    2009-01-01

    Lower Cretaceous strata beneath the Alaska North Slope include clinoform depositional sequences that filled the western Colville foreland basin and overstepped the Beaufort rift shoulder. Analysis of Albian clinoform sequences with two-dimensional (2D) seismic data resulted in the recognition of seismic facies inferred to represent lowstand, transgressive and highstand systems tracts. These are stacked to produce shelf-margin trajectories that appear in low-resolution seismic data to alternate between aggradational and progradational. Higher-resolution seismic data reveal shelf-margin trajectories that are more complex, particularly in net-aggradational areas, where three patterns commonly are observed: (1) a negative (downward) step across the sequence boundary followed by mostly aggradation in the lowstand systems tract (LST), (2) a positive (upward) step across the sequence boundary followed by mostly progradation in the LST and (3) an upward backstep across a mass-failure d??collement. These different shelf-margin trajectories are interpreted as (1) fall of relative sea level below the shelf edge, (2) fall of relative sea level to above the shelf edge and (3) mass-failure removal of shelf-margin sediment. Lowstand shelf margins mapped using these criteria are oriented north-south in the foreland basin, indicating longitudinal filling from west to east. The shelf margins turn westward in the north, where the clinoform depositional system overstepped the rift shoulder, and turn eastward in the south, suggesting progradation of depositional systems from the ancestral Brooks Range into the foredeep. Lowstand shelf-margin orientations are consistently perpendicular to clinoform-foreset-dip directions. Although the Albian clinoform sequences of the Alaska North Slope are generally similar in stratal geometry to clinoform sequences elsewhere, they are significantly thicker. Clinoform-sequence thickness ranges from 600-1000 m in the north to 1700-2000 m in the south

  15. Seismic rupture modelling, strong motion prediction and seismic hazard assessment: fundamental and applied approaches

    International Nuclear Information System (INIS)

    Berge-Thierry, C.

    2007-05-01

    The defence to obtain the 'Habilitation a Diriger des Recherches' is a synthesis of the research work performed since the end of my Ph D. thesis in 1997. This synthesis covers the two years as post doctoral researcher at the Bureau d'Evaluation des Risques Sismiques at the Institut de Protection (BERSSIN), and the seven consecutive years as seismologist and head of the BERSSIN team. This work and the research project are presented in the framework of the seismic risk topic, and particularly with respect to the seismic hazard assessment. Seismic risk combines seismic hazard and vulnerability. Vulnerability combines the strength of building structures and the human and economical consequences in case of structural failure. Seismic hazard is usually defined in terms of plausible seismic motion (soil acceleration or velocity) in a site for a given time period. Either for the regulatory context or the structural specificity (conventional structure or high risk construction), seismic hazard assessment needs: to identify and locate the seismic sources (zones or faults), to characterize their activity, to evaluate the seismic motion to which the structure has to resist (including the site effects). I specialized in the field of numerical strong-motion prediction using high frequency seismic sources modelling and forming part of the IRSN allowed me to rapidly working on the different tasks of seismic hazard assessment. Thanks to the expertise practice and the participation to the regulation evolution (nuclear power plants, conventional and chemical structures), I have been able to work on empirical strong-motion prediction, including site effects. Specific questions related to the interface between seismologists and structural engineers are also presented, especially the quantification of uncertainties. This is part of the research work initiated to improve the selection of the input ground motion in designing or verifying the stability of structures. (author)

  16. Evaluation and assessment of nuclear power plant seismic methodology

    Energy Technology Data Exchange (ETDEWEB)

    Bernreuter, D.; Tokarz, F.; Wight, L.; Smith, P.; Wells, J.; Barlow, R.

    1977-03-01

    The major emphasis of this study is to develop a methodology that can be used to assess the current methods used for assuring the seismic safety of nuclear power plants. The proposed methodology makes use of system-analysis techniques and Monte Carlo schemes. Also, in this study, we evaluate previous assessments of the current seismic-design methodology.

  17. Evaluation and assessment of nuclear power plant seismic methodology

    International Nuclear Information System (INIS)

    Bernreuter, D.; Tokarz, F.; Wight, L.; Smith, P.; Wells, J.; Barlow, R.

    1977-01-01

    The major emphasis of this study is to develop a methodology that can be used to assess the current methods used for assuring the seismic safety of nuclear power plants. The proposed methodology makes use of system-analysis techniques and Monte Carlo schemes. Also, in this study, we evaluate previous assessments of the current seismic-design methodology

  18. Seismic assessment of a site using the time series method

    International Nuclear Information System (INIS)

    Krutzik, N.J.; Rotaru, I.; Bobei, M.; Mingiuc, C.; Serban, V.; Androne, M.

    1997-01-01

    To increase the safety of a NPP located on a seismic site, the seismic acceleration level to which the NPP should be qualified must be as representative as possible for that site, with a conservative degree of safety but not too exaggerated. The consideration of the seismic events affecting the site as independent events and the use of statistic methods to define some safety levels with very low annual occurrence probability (10 -4 ) may lead to some exaggerations of the seismic safety level. The use of some very high value for the seismic acceleration imposed by the seismic safety levels required by the hazard analysis may lead to very costly technical solutions that can make the plant operation more difficult and increase maintenance costs. The considerations of seismic events as a time series with dependence among the events produced, may lead to a more representative assessment of a NPP site seismic activity and consequently to a prognosis on the seismic level values to which the NPP would be ensured throughout its life-span. That prognosis should consider the actual seismic activity (including small earthquakes in real time) of the focuses that affect the plant site. The paper proposes the applications of Autoregressive Time Series to issue a prognosis on the seismic activity of a focus and presents the analysis on Vrancea focus that affects NPP Cernavoda site, by this method. The paper also presents the manner to analyse the focus activity as per the new approach and it assesses the maximum seismic acceleration that may affect NPP Cernavoda throughout its life-span (∼ 30 years). Development and applications of new mathematical analysis method, both for long - and short - time intervals, may lead to important contributions in the process of foretelling the seismic events in the future. (authors)

  19. 77 FR 55510 - Guidance on Performing a Seismic Margin Assessment

    Science.gov (United States)

    2012-09-10

    ... Guidance for the Individual Plant Examination of External Events (IPEEE) for Severe Accident...-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident,'' hereafter called the ``March...

  20. An assessment of seismic monitoring in the United States; requirement for an Advanced National Seismic System

    Science.gov (United States)

    ,

    1999-01-01

    This report assesses the status, needs, and associated costs of seismic monitoring in the United States. It sets down the requirement for an effective, national seismic monitoring strategy and an advanced system linking national, regional, and urban monitoring networks. Modernized seismic monitoring can provide alerts of imminent strong earthquake shaking; rapid assessment of distribution and severity of earthquake shaking (for use in emergency response); warnings of a possible tsunami from an offshore earthquake; warnings of volcanic eruptions; information for correctly characterizing earthquake hazards and for improving building codes; and data on response of buildings and structures during earthquakes, for safe, cost-effective design, engineering, and construction practices in earthquake-prone regions.

  1. Geology of the continental margin beneath Santa Monica Bay, Southern California, from seismic-reflection data

    Science.gov (United States)

    Fisher, M.A.; Normark, W.R.; Bohannon, R.G.; Sliter, R.W.; Calvert, A.J.

    2003-01-01

    We interpret seismic-reflection data, which were collected in Santa Monica Bay using a 70-in3 generator-injector air gun, to show the geologic structure of the continental shelf and slope and of the deep-water, Santa Monica and San Pedro Basins. The goal of this research is to investigate the earthquake hazard posed to urban areas by offshore faults. These data reveal that northwest of the Palos Verdes Peninsula, the Palos Verdes Fault neither offsets the seafloor nor cuts through an undeformed sediment apron that postdates the last sea level rise. Other evidence indicates that this fault extends northwest beneath the shelf in the deep subsurface. However, other major faults in the study area, such as the Dume and San Pedro Basin Faults, were active recently, as indicated by an arched seafloor and offset shallow sediment. Rocks under the lower continental slope are deformed to differing degrees on opposite sides of Santa Monica Canyon. Northwest of this canyon, the continental slope is underlain by a little-deformed sediment apron; the main structures that deform this apron are two lower-slope anticlines that extend toward Point Dume and are cored by faults showing reverse or thrust separation. Southeast of Santa Monica Canyon, lower-slope rocks are deformed by a complex arrangement of strike-slip, normal, and reverse faults. The San Pedro Escarpment rises abruptly along the southeast side of Santa Monica Canyon. Reverse faults and folds underpinning this escarpment steepen progressively southeastward. Locally they form flower structures and cut downward into basement rocks. These faults merge downward with the San Pedro Basin fault zone, which is nearly vertical and strike slip. The escarpment and its attendant structures diverge from this strike-slip fault zone and extend for 60 km along the margin, separating the continental shelf from the deep-water basins. The deep-water Santa Monica Basin has large extent but is filled with only a thin (less than 1.5-km

  2. Deep structure of the continental margin and basin off Greater Kabylia, Algeria - New insights from wide-angle seismic data modeling and multichannel seismic interpretation

    Science.gov (United States)

    Aïdi, Chafik; Beslier, Marie-Odile; Yelles-Chaouche, Abdel Karim; Klingelhoefer, Frauke; Bracene, Rabah; Galve, Audrey; Bounif, Abdallah; Schenini, Laure; Hamai, Lamine; Schnurle, Philippe; Djellit, Hamou; Sage, Françoise; Charvis, Philippe; Déverchère, Jacques

    2018-03-01

    During the Algerian-French SPIRAL survey aimed at investigating the deep structure of the Algerian margin and basin, two coincident wide-angle and reflection seismic profiles were acquired in central Algeria, offshore Greater Kabylia, together with gravimetric, bathymetric and magnetic data. This 260 km-long offshore-onshore profile spans the Balearic basin, the central Algerian margin and the Greater Kabylia block up to the southward limit of the internal zones onshore. Results are obtained from modeling and interpretation of the combined data sets. The Algerian basin offshore Greater Kabylia is floored by a thin oceanic crust ( 4 km) with P-wave velocities ranging between 5.2 and 6.8 km/s. In the northern Hannibal High region, the atypical 3-layer crustal structure is interpreted as volcanic products stacked over a thin crust similar to that bordering the margin and related to Miocene post-accretion volcanism. These results support a two-step back-arc opening of the west-Algerian basin, comprising oceanic crust accretion during the first southward stage, and a magmatic and probably tectonic reworking of this young oceanic basement during the second, westward, opening phase. The structure of the central Algerian margin is that of a narrow ( 70 km), magma-poor rifted margin, with a wider zone of distal thinned continental crust than on the other margin segments. There is no evidence for mantle exhumation in the sharp ocean-continent transition, but transcurrent movements during the second opening phase may have changed its initial geometry. The Plio-Quaternary inversion of the margin related to ongoing convergence between Africa and Eurasia is expressed by a blind thrust system under the margin rising toward the surface at the slope toe, and by an isostatic disequilibrium resulting from opposite flexures of two plates decoupled at the continental slope. This disequilibrium is likely responsible for the peculiar asymmetrical shape of the crustal neck that may thus

  3. Modeling the conversion of hydroacoustic to seismic energy at island and continental margins: preliminary analysis of Ascension Island data

    International Nuclear Information System (INIS)

    Harben, P.; Rodgers, A.

    1999-01-01

    Seismic stations at islands and continental margins will be an essential component of the International Monitoring System (IMS) for event location and identification in support of Comprehensive Nuclear-Test-Ban Treaty (CTBT) monitoring. Particularly important will be the detection and analysis of hydroacoustic-to-seismic converted waves (T-phases) at island or continental margins. Acoustic waves generated by sources in or near the ocean propagate for long distances very efficiently due to the ocean sound speed channel (SOFAR) and low attenuation. When ocean propagating acoustic waves strike an island or continental margin they are converted to seismic (elastic) waves. We are using a finite difference code to model the conversion of hydroacoustic T-waves at an island or continental margin. Although ray-based methods are far more efficient for modeling long-range ( and gt; 1000 km) high-frequency hydroacoustic propagation, the finite difference method has the advantage of being able to model both acoustic and elastic wave propagation for a broad range of frequencies. The method allows us to perform simulations of T-phases to relatively high frequencies (( and gt;=)10 Hz). Of particular interest is to identify factors that affect the efficiency of T-phase conversion, such as the topographic slope and roughness at the conversion point and elastic velocity structure within the island or continent. Previous studies have shown that efficient T-phase conversion occurs when the topographic slope at the conversion point is steep (Cansi and Bethoux, 1985; Talandier and Okal, 1998). Another factor impacting T-phase conversion may be the near-shore structure of the sound channel. It is well known that the depth to the sound channel axis decreases in shallow waters. This can weaken the channeled hydroacoustic wave. Elastic velocity structure within the island or continent will impact how the converted seismic wave is refracted to recording stations at the surface and thus impact

  4. Seismic assessment of a site using the time series method

    International Nuclear Information System (INIS)

    Krutzik, N.J.; Rotaru, I.; Bobei, M.; Mingiuc, C.; Serban, V.; Androne, M.

    2001-01-01

    1. To increase the safety of a NPP located on a seismic site, the seismic acceleration level to which the NPP should be qualified must be as representative as possible for that site, with a conservative degree of safety but not too exaggerated. 2. The consideration of the seismic events affecting the site as independent events and the use of statistic methods to define some safety levels with very low annual occurrence probabilities (10 -4 ) may lead to some exaggerations of the seismic safety level. 3. The use of some very high values for the seismic accelerations imposed by the seismic safety levels required by the hazard analysis may lead to very expensive technical solutions that can make the plant operation more difficult and increase the maintenance costs. 4. The consideration of seismic events as a time series with dependence among the events produced may lead to a more representative assessment of a NPP site seismic activity and consequently to a prognosis on the seismic level values to which the NPP would be ensured throughout its life-span. That prognosis should consider the actual seismic activity (including small earthquakes in real time) of the focuses that affect the plant site. The method is useful for two purposes: a) research, i.e. homogenizing the history data basis by the generation of earthquakes during periods lacking information and correlation of the information with the existing information. The aim is to perform the hazard analysis using a homogeneous data set in order to determine the seismic design data for a site; b) operation, i.e. the performance of a prognosis on the seismic activity on a certain site and consideration of preventive measures to minimize the possible effects of an earthquake. 5. The paper proposes the application of Autoregressive Time Series to issue a prognosis on the seismic activity of a focus and presents the analysis on Vrancea focus that affects Cernavoda NPP site by this method. 6. The paper also presents the

  5. Assessment of bioenergy potential on marginal land in China

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Dafang; Jiang, Dong; Liu, Lei; Huang, Yaohuan [Data Center for Resources and Environmental Sciences, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A Datun Road, Chaoyang District, Beijing 100101 (China)

    2011-02-15

    Bioenergy developed from energy plants will play a more and more important role in future energy supply. Much attention has been paid to energy plants in recent years. As China has fairly limited cultivated land resources, the bioenergy development may mainly rely on the exploitation of marginal land. This study focused on the assessment of marginal land resources and bio-fuel potential in China using newly acquired data and Geographic Information System (GIS) techniques. A multi-factor analysis method was adopted to identify marginal lands for bioenergy development in China, with data of several main types of energy plants on the eco-environmental requirements and natural habits employed. A combined planting zonation strategy was proposed, which was targeted for five species of energy plants including Helianthus tuberous L., Pistacia chinensis, Jatropha curcas L., Cassava and Vernicia fordii. The results indicated that total area of marginal land exploitable for development of energy plants on a large scale was about 43.75 million ha. If 10% of this marginal land was fully utilized for growing the energy plants, the production of bio-fuel would be 13.39 million tons. (author)

  6. Probabilistic seismic hazard assessment for Point Lepreau Generating Station

    Energy Technology Data Exchange (ETDEWEB)

    Mullin, D. [New Brunswick Power Corp., Point Lepreau Generating Station, Lepreau, New Brunswick (Canada); Lavine, A. [AMEC Foster Wheeler Environment and Infrastructure Americas, Oakland, California (United States); Egan, J. [SAGE Engineers, Oakland, California (United States)

    2015-09-15

    A Probabilistic Seismic Hazard Assessment (PSHA) has been performed for the Point Lepreau Generating Station (PLGS). The objective is to provide characterization of the earthquake ground shaking that will be used to evaluate seismic safety. The assessment is based on the current state of knowledge of the informed scientific and engineering community regarding earthquake hazards in the site region, and includes two primary components-a seismic source model and a ground motion model. This paper provides the methodology and results of the PLGS PSHA. The implications of the updated hazard information for site safety are discussed in a separate paper. (author)

  7. Probabilistic seismic hazard assessment for Point Lepreau Generating Station

    Energy Technology Data Exchange (ETDEWEB)

    Mullin, D., E-mail: dmullin@nbpower.com [New Brunswick Power Corporation, Point Lepreau Generating Station, Point Lepreau, NB (Canada); Lavine, A., E-mail: alexis.lavine@amecfw.com [AMEC Foster Wheeler Environment & Infrastructure Americas, Oakland, CA (United States); Egan, J., E-mail: jegan@sageengineers.com [SAGE Engineers, Oakland, CA (United States)

    2015-07-01

    A Probabilistic Seismic Hazard Assessment (PSHA) has been performed for the Point Lepreau Generating Station (PLGS). The objective is to provide characterization of the earthquake ground shaking that will be used to evaluate seismic safety. The assessment is based on the current state of knowledge of the informed scientific and engineering community regarding earthquake hazards in the site region, and includes two primary components--a seismic source model and a ground motion model. This paper provides the methodology and results of the PLGS PSHA. The implications of the updated hazard information for site safety are discussed in a separate paper. (author)

  8. Probabilistic seismic vulnerability and risk assessment of stone masonry structures

    Science.gov (United States)

    Abo El Ezz, Ahmad

    Earthquakes represent major natural hazards that regularly impact the built environment in seismic prone areas worldwide and cause considerable social and economic losses. The high losses incurred following the past destructive earthquakes promoted the need for assessment of the seismic vulnerability and risk of the existing buildings. Many historic buildings in the old urban centers in Eastern Canada such as Old Quebec City are built of stone masonry and represent un-measurable architectural and cultural heritage. These buildings were built to resist gravity loads only and generally offer poor resistance to lateral seismic loads. Seismic vulnerability assessment of stone masonry buildings is therefore the first necessary step in developing seismic retrofitting and pre-disaster mitigation plans. The objective of this study is to develop a set of probability-based analytical tools for efficient seismic vulnerability and uncertainty analysis of stone masonry buildings. A simplified probabilistic analytical methodology for vulnerability modelling of stone masonry building with systematic treatment of uncertainties throughout the modelling process is developed in the first part of this study. Building capacity curves are developed using a simplified mechanical model. A displacement based procedure is used to develop damage state fragility functions in terms of spectral displacement response based on drift thresholds of stone masonry walls. A simplified probabilistic seismic demand analysis is proposed to capture the combined uncertainty in capacity and demand on fragility functions. In the second part, a robust analytical procedure for the development of seismic hazard compatible fragility and vulnerability functions is proposed. The results are given by sets of seismic hazard compatible vulnerability functions in terms of structure-independent intensity measure (e.g. spectral acceleration) that can be used for seismic risk analysis. The procedure is very efficient for

  9. Toward uniform probabilistic seismic hazard assessments for Southeast Asia

    Science.gov (United States)

    Chan, C. H.; Wang, Y.; Shi, X.; Ornthammarath, T.; Warnitchai, P.; Kosuwan, S.; Thant, M.; Nguyen, P. H.; Nguyen, L. M.; Solidum, R., Jr.; Irsyam, M.; Hidayati, S.; Sieh, K.

    2017-12-01

    Although most Southeast Asian countries have seismic hazard maps, various methodologies and quality result in appreciable mismatches at national boundaries. We aim to conduct a uniform assessment across the region by through standardized earthquake and fault databases, ground-shaking scenarios, and regional hazard maps. Our earthquake database contains earthquake parameters obtained from global and national seismic networks, harmonized by removal of duplicate events and the use of moment magnitude. Our active-fault database includes fault parameters from previous studies and from the databases implemented for national seismic hazard maps. Another crucial input for seismic hazard assessment is proper evaluation of ground-shaking attenuation. Since few ground-motion prediction equations (GMPEs) have used local observations from this region, we evaluated attenuation by comparison of instrumental observations and felt intensities for recent earthquakes with predicted ground shaking from published GMPEs. We then utilize the best-fitting GMPEs and site conditions into our seismic hazard assessments. Based on the database and proper GMPEs, we have constructed regional probabilistic seismic hazard maps. The assessment shows highest seismic hazard levels near those faults with high slip rates, including the Sagaing Fault in central Myanmar, the Sumatran Fault in Sumatra, the Palu-Koro, Matano and Lawanopo Faults in Sulawesi, and the Philippine Fault across several islands of the Philippines. In addition, our assessment demonstrates the important fact that regions with low earthquake probability may well have a higher aggregate probability of future earthquakes, since they encompass much larger areas than the areas of high probability. The significant irony then is that in areas of low to moderate probability, where building codes are usually to provide less seismic resilience, seismic risk is likely to be greater. Infrastructural damage in East Malaysia during the 2015

  10. Assessment of Seismic Vulnerability of Reinforced Concrete Frame buildings

    Directory of Open Access Journals (Sweden)

    Fatiha Cherifi

    2018-01-01

    Full Text Available The seismic activity remains strong in the north of Algeria since no less than 30 earthquakes per month are recorded. The large number of structures built before the introduction of the seismic standards represents a high seismic risk. Analysis of damage suffered during the last earthquakes highlighted the vulnerability of the existing structures. In this study the seismic behavior of the existing buildings in Tizi-Ouzou city, located in the north of Algeria, is investigated. To make this assessment, a database was created following a building inventory based on a set of technical folders and field visits. The listed buildings have been classified into different typologies. Only reinforced concrete frame buildings are considered in this paper. The approach adopted to estimate structures damage is based on four main steps: 1 construction of capacity curves using static nonlinear method “push-over”, 2 estimate of seismic hazard, 3 determination of performance points, and finally 4 deduction of damage levels.

  11. Assessment of seismic design response factors of concrete wall buildings

    Science.gov (United States)

    Mwafy, Aman

    2011-03-01

    To verify the seismic design response factors of high-rise buildings, five reference structures, varying in height from 20- to 60-stories, were selected and designed according to modern design codes to represent a wide range of concrete wall structures. Verified fiber-based analytical models for inelastic simulation were developed, considering the geometric nonlinearity and material inelasticity of the structural members. The ground motion uncertainty was accounted for by employing 20 earthquake records representing two seismic scenarios, consistent with the latest understanding of the tectonic setting and seismicity of the selected reference region (UAE). A large number of Inelastic Pushover Analyses (IPAs) and Incremental Dynamic Collapse Analyses (IDCAs) were deployed for the reference structures to estimate the seismic design response factors. It is concluded that the factors adopted by the design code are adequately conservative. The results of this systematic assessment of seismic design response factors apply to a wide variety of contemporary concrete wall buildings with various characteristics.

  12. Assessing the seismic risk potential of South America

    Science.gov (United States)

    Jaiswal, Kishor; Petersen, Mark D.; Harmsen, Stephen; Smoczyk, Gregory M.

    2016-01-01

    We present here a simplified approach to quantifying regional seismic risk. The seismic risk for a given region can be inferred in terms of average annual loss (AAL) that represents long-term value of earthquake losses in any one year caused from a long-term seismic hazard. The AAL are commonly measured in the form of earthquake shaking-induced deaths, direct economic impacts or indirect losses caused due to loss of functionality. In the context of South American subcontinent, the analysis makes use of readily available public data on seismicity, population exposure, and the hazard and vulnerability models for the region. The seismic hazard model was derived using available seismic catalogs, fault databases, and the hazard methodologies that are analogous to the U.S. Geological Survey’s national seismic hazard mapping process. The Prompt Assessment of Global Earthquakes for Response (PAGER) system’s direct empirical vulnerability functions in terms of fatality and economic impact were used for performing exposure and risk analyses. The broad findings presented and the risk maps produced herein are preliminary, yet they do offer important insights into the underlying zones of high and low seismic risks in the South American subcontinent. A more detailed analysis of risk may be warranted by engaging local experts, especially in some of the high risk zones identified through the present investigation.

  13. Margins in high temperature leak-before-break assessments

    International Nuclear Information System (INIS)

    Budden, P.J.; Hooton, D.G.

    1997-01-01

    Developments in the defect assessment procedure R6 to include high-temperature mechanisms in Leak-before-Break arguments are described. In particular, the effect of creep on the time available to detect a leak and on the crack opening area, and hence leak rate, is discussed. The competing influence of these two effects is emphasized by an example. The application to Leak-before-Break of the time-dependent failure assessment diagram approach for high temperature defect assessment is then outlined. The approach is shown to be of use in assessing the erosion of margins by creep

  14. Margins in high temperature leak-before-break assessments

    Energy Technology Data Exchange (ETDEWEB)

    Budden, P.J.; Hooton, D.G.

    1997-04-01

    Developments in the defect assessment procedure R6 to include high-temperature mechanisms in Leak-before-Break arguments are described. In particular, the effect of creep on the time available to detect a leak and on the crack opening area, and hence leak rate, is discussed. The competing influence of these two effects is emphasized by an example. The application to Leak-before-Break of the time-dependent failure assessment diagram approach for high temperature defect assessment is then outlined. The approach is shown to be of use in assessing the erosion of margins by creep.

  15. Seismic damage assessment of reinforced concrete containment structures

    International Nuclear Information System (INIS)

    Cho, HoHyun; Koh, Hyun-Moo; Hyun, Chang-Hun; Kim, Moon-Soo; Shin, Hyun Mock

    2003-01-01

    This paper presents a procedure for assessing seismic damage of concrete containment structures using the nonlinear time-history numerical analysis. For this purpose, two kinds of damage index are introduced at finite element and structural levels. Nonlinear finite element analysis for the containment structure applies PSC shell elements using a layered approach leading to damage indices at finite element and structural levels, which are then used to assess the seismic damage of the containment structure. As an example of such seismic damage assessment, seismic damages of the containment structure of Wolsong I nuclear power plant in Korea are evaluated against 30 artificial earthquakes generated with a wide range of PGA according to US NRC regulatory guide 1.60. Structural responses and corresponding damage index according to the level of PGA and nonlinearity are investigated. It is also shown that the containment structure behaves elastically for earthquakes corresponding to or lower than DBE. (author)

  16. New Insights into Passive Margin Development from a Global Deep Seismic Reflection Dataset

    Science.gov (United States)

    Bellingham, Paul; Pindell, James; Graham, Rod; Horn, Brian

    2014-05-01

    The kinematic and dynamic evolution of the world's passive margins is still poorly understood. Yet the need to replace reserves, a high oil price and advances in drilling technology have pushed the international oil and gas industry to explore in the deep and ultra-deep waters of the continental margins. To support this exploration and help understand these margins, ION-GXT has acquired, processed and interpreted BasinSPAN surveys across many of the world's passive margins. Observations from these data lead us to consider the modes of subsidence and uplift at both volcanic and non-volcanic margins. At non-volcanic margins, it appears that frequently much of the subsidence post-dates major rifting and is not thermal in origin. Rather the subsidence is associated with extensional displacement on a major fault or shear zone running at least as deep as the continental Moho. We believe that the subsidence is structural and is probably associated with the pinching out (boudinage) of the Lower Crust so that the Upper crust effectively collapses onto the mantle. Eventually this will lead to the exhumation of the sub-continental mantle at the sea bed. Volcanic margins present more complex challenges both in terms of imaging and interpretation. The addition of volcanic and plutonic material into the system and dynamic effects all impact subsidence and uplift. However, we will show some fundamental observations regarding the kinematic development of volcanic margins and especially SDRs which demonstate that the process of collapse and the development of shear zones within and below the crust are also in existence at this type of margin. A model is presented of 'magma welds' whereby packages of SDRs collapse onto an emerging sub-crustal shear zone and it is this collapse which creates the commonly observed SDR geometry. Examples will be shown from East India, Newfoundland, Brazil, Argentina and the Gulf of Mexico.

  17. AECB workshop on seismic hazard assessment in southern Ontario

    International Nuclear Information System (INIS)

    Stepp, J.C.; Price, R.A.; Coppersmith, K.J.; Klimkiewicz, G.C.; McGuire, R.K.

    1995-10-01

    The purpose of the workshop was to review available geological and seismological data which could affect earthquake occurrence in southern Ontario and to develop a consensus on approaches that should be adopted for characterization of seismic hazard. The workshop was structured in technical sessions to focus presentations and discussions on four technical issues relevant to seismic hazard in southern Ontario, as follows: (1) The importance of geological and geophysical observations for the determination of seismic sources, (2) Methods and approaches which may be adopted for determining seismic sources based on integrated interpretations of geological and seismological information, (3) Methods and data which should be used for characterizing the seismicity parameters of seismic sources, and (4) Methods for assessment of vibratory ground motion hazard. The format of each session involved invited presentations of relevant data followed by open presentations by participants, a general discussion focusing on the relevance of the presented information for seismic hazard assessment in southern Ontario, then development of conclusions and recommendations. In the final session, the conclusions and recommendations were summarized and an open discussion was held to develop consensus. This report presents perspective summaries of the workshop technical sessions together with conclusions and recommendations prepared by the session chairs and the general chairman. 2 refs

  18. Seismic and structural characterization of the fluid bypass system using 3D and partial stack seismic from passive margin: inside the plumbing system.

    Science.gov (United States)

    Iacopini, David; Maestrelli, Daniele; Jihad, Ali; Bond, Clare; Bonini, Marco

    2017-04-01

    In recent years enormous attention has been paid to the understanding of the process and mechanism controlling the gas seepage and more generally the fluid expulsion affecting the earth system from onshore to offshore environment. This is because of their demonstrated impact to our environment, climate change and during subsea drilling operation. Several example from active and paleo system has been so far characterized and proposed using subsurface exploration, geophysical and geochemical monitoring technology approaches with the aims to explore what trigger and drive the overpressure necessary maintain the fluid/gas/material expulsion and what are the structure that act as a gateway for gaseous fluid and unconsolidated rock. In this contribution we explore a series of fluid escape structure (ranging from seepage pipes to large blowout pipes structure of km length) using 3D and partial stack seismic data from two distinctive passive margin from the north sea (Loyal field, West Shetland) and the Equatorial Brazil (Ceara' Basin). We will focuses on the characterization of the plumbing system internal architecture and, for selected example, exploring the AVO response (using partial stack) of the internal fluid/unconsolidated rock. The detailed seismic mapping and seismic attributes analysis of the conduit system helped us to recover some detail from the signal response of the chimney internal structures. We observed: (1) small to medium seeps and pipes following structural or sedimentary discontinuities (2) large pipes (probably incipient mud volcanoes) and blowup structures propagating upward irrespective of pre-existing fault by hydraulic fracturing and assisted by the buoyancy of a fluidised and mobilised mud-hydrocarbon mixture. The reflector termination observed inside the main conduits, the distribution of stacked bright reflectors and the AVO analysis suggests an evolution of mechanisms (involving mixture of gas, fluid and probably mud) during pipe birth and

  19. Methodology for the Seismic risk assessment in segments of fault

    International Nuclear Information System (INIS)

    1997-02-01

    The present study establishes the most adequate methods of Seismic Hazard Assessment for the Iberian Peninsula, in particular for low seismicity areas, through a review of methods used in other countries and its application to a certain area in Spain. In this area the geological context and recent activity of a specific tectonic structure is studied in detail, in order to asses its slip rate, and therefore, its capability of generating earthquakes. In the first stage of this project a review of Seismic Hazard Assessment methods used outside Spain was carried out, as well as, a study of several spanish cases. This stage also comprises a review of the spanish seismic record and a study of the general peninsular neotectonic context, this latter to select a particular fault for the next stage. (Author) 117 refs

  20. Validation of seismic probabilistic risk assessments of nuclear power plants

    International Nuclear Information System (INIS)

    Ellingwood, B.

    1994-01-01

    A seismic probabilistic risk assessment (PRA) of a nuclear plant requires identification and information regarding the seismic hazard at the plant site, dominant accident sequences leading to core damage, and structure and equipment fragilities. Uncertainties are associated with each of these ingredients of a PRA. Sources of uncertainty due to seismic hazard and assumptions underlying the component fragility modeling may be significant contributors to uncertainty in estimates of core damage probability. Design and construction errors also may be important in some instances. When these uncertainties are propagated through the PRA, the frequency distribution of core damage probability may span three orders of magnitude or more. This large variability brings into question the credibility of PRA methods and the usefulness of insights to be gained from a PRA. The sensitivity of accident sequence probabilities and high-confidence, low probability of failure (HCLPF) plant fragilities to seismic hazard and fragility modeling assumptions was examined for three nuclear power plants. Mean accident sequence probabilities were found to be relatively insensitive (by a factor of two or less) to: uncertainty in the coefficient of variation (logarithmic standard deviation) describing inherent randomness in component fragility; truncation of lower tail of fragility; uncertainty in random (non-seismic) equipment failures (e.g., diesel generators); correlation between component capacities; and functional form of fragility family. On the other hand, the accident sequence probabilities, expressed in the form of a frequency distribution, are affected significantly by the seismic hazard modeling, including slopes of seismic hazard curves and likelihoods assigned to those curves

  1. Worldwide Assessment of the Status of Seismic Zonation, Fourth International Forum on Seismic Zonation, Proceedings

    Science.gov (United States)

    Hays, W.W.

    1994-01-01

    We are pleased to provide you with information developed for the Fourth International Forum on Seismic Zonation which will be convened in two locations year in conjunction two major international meetings. The objectives are: 1) to assess the status of seismic zonation in every country of the world, 2) to evaluate the reasons for advances and new initiatives, and 3) to foster continued cooperation. Seismic zonation is the process that leads to risk reduction and sustainability of new development. It is based on the division of a geographic region into smaller areas or zones on the basis of an integrated assessment of the hazard, built, and policy environments of the region. Seismic zonation depends on hazard mapping performed on national/regional, subregional, and urban (i.e., microzonation) scales depending on the particular application. We gratefully acknowledge the written communications of many professionals who responded to our request for information. Also, we acknowledge the use of information contained in five valuable reports (see directories in the Appendices for information on where to obtain copies of the reports): 1. United Nations, 1990, Cooperative Project for Seismic Risk Reduction in the Mediterranean Region (SEISMED), proceedings, Office of the United Nations Disaster Relief Coordinator, Geneva, Switzerland, 3 vols. (Franco Maranzana -

  2. Crustal Structure of the Ionian Basin and Eastern Sicily Margin: Results From a Wide-Angle Seismic Survey

    Science.gov (United States)

    Dellong, David; Klingelhoefer, Frauke; Kopp, Heidrun; Graindorge, David; Margheriti, Lucia; Moretti, Milena; Murphy, Shane; Gutscher, Marc-Andre

    2018-03-01

    In the Ionian Sea (central Mediterranean) the slow convergence between Africa and Eurasia results in the formation of a narrow subduction zone. The nature of the crust of the subducting plate remains debated and could represent the last remnants of the Neo-Tethys ocean. The origin of the Ionian basin is also under discussion, especially concerning the rifting mechanisms as the Malta Escarpment could represent a remnant of this opening. This subduction retreats toward the south-east (motion occurring since the last 35 Ma) but is confined to the narrow Ionian basin. A major lateral slab tear fault is required to accommodate the slab roll-back. This fault is thought to propagate along the eastern Sicily margin but its precise location remains controversial. This study focuses on the deep crustal structure of the eastern Sicily margin and the Malta Escarpment. We present two two-dimensional P wave velocity models obtained from forward modeling of wide-angle seismic data acquired onboard the R/V Meteor during the DIONYSUS cruise in 2014. The results image an oceanic crust within the Ionian basin as well as the deep structure of the Malta Escarpment, which presents characteristics of a transform margin. A deep and asymmetrical sedimentary basin is imaged south of the Messina strait and seems to have opened between the Calabrian and Peloritan continental terranes. The interpretation of the velocity models suggests that the tear fault is located east of the Malta Escarpment, along the Alfeo fault system.

  3. Probabilistic seismic hazard assessment for the effect of vertical ground motions on seismic response of highway bridges

    Science.gov (United States)

    Yilmaz, Zeynep

    Typically, the vertical component of the ground motion is not considered explicitly in seismic design of bridges, but in some cases the vertical component can have a significant effect on the structural response. The key question of when the vertical component should be incorporated in design is answered by the probabilistic seismic hazard assessment study incorporating the probabilistic seismic demand models and ground motion models. Nonlinear simulation models with varying configurations of an existing bridge in California were considered in the analytical study. The simulation models were subjected to the set of selected ground motions in two stages: at first, only horizontal components of the motion were applied; while in the second stage the structures were subjected to both horizontal and vertical components applied simultaneously and the ground motions that produced the largest adverse effects on the bridge system were identified. Moment demand in the mid-span and at the support of the longitudinal girder and the axial force demand in the column are found to be significantly affected by the vertical excitations. These response parameters can be modeled using simple ground motion parameters such as horizontal spectral acceleration and vertical spectral acceleration within 5% to 30% error margin depending on the type of the parameter and the period of the structure. For a complete hazard assessment, both of these ground motion parameters explaining the structural behavior should also be modeled. For the horizontal spectral acceleration, Abrahamson and Silva (2008) model was used within many available standard model. A new NGA vertical ground motion model consistent with the horizontal model was constructed. These models are combined in a vector probabilistic seismic hazard analyses. Series of hazard curves developed and presented for different locations in Bay Area for soil site conditions to provide a roadmap for the prediction of these features for future

  4. Probabilistic Seismic Hazard Assessment for Northeast India Region

    Science.gov (United States)

    Das, Ranjit; Sharma, M. L.; Wason, H. R.

    2016-08-01

    Northeast India bounded by latitudes 20°-30°N and longitudes 87°-98°E is one of the most seismically active areas in the world. This region has experienced several moderate-to-large-sized earthquakes, including the 12 June, 1897 Shillong earthquake ( M w 8.1) and the 15 August, 1950 Assam earthquake ( M w 8.7) which caused loss of human lives and significant damages to buildings highlighting the importance of seismic hazard assessment for the region. Probabilistic seismic hazard assessment of the region has been carried out using a unified moment magnitude catalog prepared by an improved General Orthogonal Regression methodology (Geophys J Int, 190:1091-1096, 2012; Probabilistic seismic hazard assessment of Northeast India region, Ph.D. Thesis, Department of Earthquake Engineering, IIT Roorkee, Roorkee, 2013) with events compiled from various databases (ISC, NEIC,GCMT, IMD) and other available catalogs. The study area has been subdivided into nine seismogenic source zones to account for local variation in tectonics and seismicity characteristics. The seismicity parameters are estimated for each of these source zones, which are input variables into seismic hazard estimation of a region. The seismic hazard analysis of the study region has been performed by dividing the area into grids of size 0.1° × 0.1°. Peak ground acceleration (PGA) and spectral acceleration ( S a) values (for periods of 0.2 and 1 s) have been evaluated at bedrock level corresponding to probability of exceedance (PE) of 50, 20, 10, 2 and 0.5 % in 50 years. These exceedance values correspond to return periods of 100, 225, 475, 2475, and 10,000 years, respectively. The seismic hazard maps have been prepared at the bedrock level, and it is observed that the seismic hazard estimates show a significant local variation in contrast to the uniform hazard value suggested by the Indian standard seismic code [Indian standard, criteria for earthquake-resistant design of structures, fifth edition, Part

  5. High resolution seismic stratigraphy and Mass Transport Deposits of the proximal continental margin, offshore Quarteira, South Portugal: Preliminary Results.

    Science.gov (United States)

    Duarte, Débora; Santos, Joana; Terrinha, Pedro; Brito, Pedro; Noiva, João; Ribeiro, Carlos; Roque, Cristina

    2017-04-01

    More than 300 nautical miles of multichannel seismic reflection data were acquired in the scope of the ASTARTE project (Assessment Strategy and Risk Reduction for Tsunamis in Europe), off Quarteira, Algarve, South Portugal. The main goal of this very high resolution multichannel seismic survey was to obtain high-resolution images of the sedimentary record to try to discern the existence of high energy events, possibly tsunami backwash deposits associated with large magnitude earthquakes generated at the Africa-Eurasia plate boundary This seismic dataset was processed at the Instituto Português do Mar e da Atmosfera (IPMA), with the SeisSpace PROMAX Seismic Processing software. A tailor-made processing flow was applied, focusing in the removal of the seafloor multiple and in the enhancement of the superficial layers. A sparker source, using with 300 J of energy and a fire rate of 0,5 s was used onboard Xunauta, an 18 m long vessel. The preliminary seismostratigraphic interpretation of the Algarve ASTARTE seismic dataset allowed the identification of a complex sequence seismic units of progradational and agradational bodies as well as Mass Transported Deposits (MTD). The MTD package of sediments has a very complex internal structure, 20m of thickness, is apparently spatially controlled by an escarpment probably associated to past sea level low stands. The MTD covers across an area, approximately parallel to an ancient coastline, with >30 km (length) x 5 km (across). Acknowledgements: This work was developed as part of the project ASTARTE (603839 FP7) supported by the grant agreement No 603839 of the European Union's Seventh. The Instituto Portugues do Mar e da Atmosfera acknowledges support by Landmark Graphics (SeisWorks) via the Landmark University Grant Program.

  6. Structure of the Lithosphere-Asthenosphere Boundary Onshore and Offshore the California Continental Margin from Three-Dimensional Seismic Anisotropy

    Science.gov (United States)

    Gomez, C. D.; Escobar, L., Sr.; Rathnayaka, S.; Weeraratne, D. S.; Kohler, M. D.

    2016-12-01

    The California continental margin, a major transform plate boundary in continental North America, is the locus of complex tectonic stress fields that are important in interpreting both remnant and ongoing deformational strain. Ancient subduction of the East Pacific Rise spreading center, the rotation and translation of tectonic blocks and inception of the San Andreas fault all contribute to the dynamic stress fields located both onshore and offshore southern California. Data obtained by the ALBACORE (Asthenospheric and Lithospheric Broadband Architecture from the California Offshore Region Experiment) and the CISN (California Integrated Seismic Network) seismic array are analyzed for azimuthal anisotropy of Rayleigh waves from 80 teleseismic events at periods 16 - 78 s. Here we invert Rayleigh wave data for shear wave velocity structure and three-dimensional seismic anisotropy in the thee regions designated within the continental margin including the continent, seafloor and California Borderlands. Preliminary results show that seismic anisotropy is resolved in multiple layers and can be used to determine the lithosphere-asthenosphere boundary (LAB) in offshore and continental regions. The oldest seafloor in our study at age 25-35 Ma indicates that the anisotropic transition across the LAB occurs at 73 km +/- 25 km with the lithospheric fast direction oriented WNW-ESE, consistent with current Pacific plate motion direction. The continent region west of the San Andreas indicates similar WNW-ESE anisotropy and LAB depth. Regions east of the San Andreas fault indicate NW-SE anisotropy transitioning to a N-S alignment at 80 km depth north of the Garlock fault. The youngest seafloor (15 - 25 Ma) and outer Borderlands indicate a more complex three layer fabric where shallow lithospheric NE-SW fast directions are perpendicular with ancient Farallon subduction arc, a mid-layer with E-W fast directions are perpendicular to remnant fossil fabric, and the deepest layer

  7. Episodic Sediment Failure in Northern Flemish Pass, Eastern Canadian Margin: Interplay of Seismicity, Contour Current Winnowing, and Excess Pore Pressures

    Science.gov (United States)

    Piper, D.

    2015-12-01

    Episodic sediment failures are recognised on continental slopes around Flemish Pass and Orphan Basin from multibeam bathymetry, seismic reflection profiles and piston cores. Seismic stratigraphy is tied to published long cores with O-isotope data back to before MIS 6 and carbonate rich Heinrich layers in places produce marker reflections in high-resolution sparker profiles. Heinrich layers, radiocarbon dates and peaks in diatom abundance provide core chronology. Slope sedimentation was strongly influenced by the Labrador Current and the silty muds show architecture characteristic of contourites. Variation in Labrador Current strength is known from the sortable silt proxy over the past 125 ka. Large slope failures were mapped from seismic reflection profiles and their age estimated from seismic stratigraphy (3-5 ka resolution) and in some cases refined from cores (1-3 ka resolution). Large slope failures occurred apparently synchronously over margin lengths of 50-350 km. Such failures were earthquake triggered: other mechanisms for producing laterally extensive synchronous failure do not apply. Triaxial shear measurements show a Su/σ' ratio of typical slope sediment of 0.48, implying considerable stability. However, some silty muds have Atterberg limits that suggest susceptibility to liquefaction under cyclic loading, particularly in Holocene deposits and by analogy those of past full interglacials. Basal failure planes of some large failures correspond with either the last interglacial or the MIS 6 glacial maximum. Comparison with seismological models suggests that the observed slope failures represent earthquakes ranging from Mw ~5.6 to ~7.6. Mean recurrence interval of M = 7 earthquakes at any point on the margin is estimated at 30 ka from seismological models and 40 ka from the sediment failure record. In northern Flemish Pass, a spatial cluster of several failures over 30 ka preceded by a long interval with no failures suggests that some other mechanism has

  8. WSEAT Shock Testing Margin Assessment Using Energy Spectra Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Sisemore, Carl; Babuska, Vit; Booher, Jason

    2018-02-01

    Several programs at Sandia National Laboratories have adopted energy spectra as a metric to relate the severity of mechanical insults to structural capacity. The purpose being to gain insight into the system's capability, reliability, and to quantify the ultimate margin between the normal operating envelope and the likely system failure point -- a system margin assessment. The fundamental concern with the use of energy metrics was that the applicability domain and implementation details were not completely defined for many problems of interest. The goal of this WSEAT project was to examine that domain of applicability and work out the necessary implementation details. The goal of this project was to provide experimental validation for the energy spectra based methods in the context of margin assessment as they relate to shock environments. The extensive test results concluded that failure predictions using energy methods did not agree with failure predictions using S-N data. As a result, a modification to the energy methods was developed following the form of Basquin's equation to incorporate the power law exponent for fatigue damage. This update to the energy-based framework brings the energy based metrics into agreement with experimental data and historical S-N data.

  9. On-line fatigue monitoring and margins probabilistic assessment

    International Nuclear Information System (INIS)

    Fournier, I.; Morilhat, P.

    1993-01-01

    An on-line computer aided system has been developed by Electricite de France, the French utility, for a fatigue monitoring of critical locations in the nuclear steam supply system. This tool, called fatiguemeter, includes as input data only existing plant parameters and is based on some conservative assumptions at several steps of the damage assessment (thermal boundary conditions, stress computation...). This paper presents recent developments performed toward a better assessing of margins involved in the complete analysis. The methodology is enlightened with an example showing the influence of plant parameters incertitude on the final stress computed at a PWR 900 MW unit pressurizer surge line nozzle. (author)

  10. Seismicity pattern: an indicator of source region of volcanism at convergent plate margins

    Czech Academy of Sciences Publication Activity Database

    Špičák, Aleš; Hanuš, Václav; Vaněk, Jiří

    2004-01-01

    Roč. 141, č. 4 (2004), s. 303-326 ISSN 0031-9201 R&D Projects: GA AV ČR IAA3012002; GA AV ČR IAA3012303; GA AV ČR KSK3012103 Institutional research plan: CEZ:AV0Z3012916 Keywords : seismicity pattern * volcanism * aseismic gap Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.370, year: 2004

  11. Seismic Safety Margins Research Program. Phase I final report - Subsystem response (Project V)

    International Nuclear Information System (INIS)

    Shieh, L.C.; Chuang, T.Y.; O'Connell, W.J.

    1981-10-01

    This document reports on (1) the computation of the responses of subsystems, given the input subsystem support motion for components and systems whose failure can lead to an accident sequence (radioactive release), and (2) the results of a sensitivity study undertaken to determine the contributions of the several links in the seismic methodology chain (SMC) - seismic input (SI), soil-structure interaction (SSI), structure response (STR), and subsystem response (SUB) - to the uncertainty in subsystem response. For the singly supported subsystems (e.g., pumps, turbines, electrical control panels, etc.), we used the spectral acceleration response of the structure at the point where the subsystem components were mounted. For the multiple supported subsystems, we developed 13 piping models of five safety-related systems, and then used the pseudostatic-mode method with multisupport input motion to compute the response parameters in terms of the parameters used in the fragility descriptions (i.e., peak resultant accelerations for valves and peak resultant moments for piping). Damping and frequency were varied to represent the sources of modeling and random uncertainty. Two codes were developed: a modified version of SAPIV which assembles the piping supports into groups depending on the support's location relative to the attached structure, and SAPPAC a stand-alone modular program from which the time-history analysis module is extracted. On the basis of our sensitivity study, we determined that the variability in the combined soil-structure interaction, structural response, and subsystem response areas contribute more to uncertainty in subsystem response than does the variability in the seismic input area, assuming an earthquake within the limited peak ground acceleration range, i.e., 0.15 to 0.30g. The seismic input variations were in terms of different earthquake time histories. (author)

  12. Seismic risk assessment for road in Indonesia

    Science.gov (United States)

    Toyfur, Mona Foralisa; Pribadi, Krishna S.

    2016-05-01

    Road networks in Indonesia consist of 446,000 km of national, provincial and local roads as well as toll highways. Indonesia is one of countries that exposed to various natural hazards, such as earthquakes, floods, landslides, etc. Within the Indonesian archipelago, several global tectonic plates interact, such as the Indo-Australian, Pacific, Eurasian, resulting in a complex geological setting, characterized by the existence of seismically active faults and subduction zones and a chain of more than one hundred active volcanoes. Roads in Indonesia are vital infrastructure needed for people and goods movement, thus supporting community life and economic activities, including promoting regional economic development. Road damages and losses due to earthquakes have not been studied widely, whereas road disruption caused enormous economic damage. The aim of this research is to develop a method to analyse risk caused by seismic hazard to roads. The seismic risk level of road segment is defined using an earthquake risk index, adopting the method of Earthquake Disaster Risk Index model developed by Davidson (1997). Using this method, road segments' risk level can be defined and compared, and road risk map can be developed as a tool for prioritizing risk mitigation programs for road networks in Indonesia.

  13. Seismic Probabilistic Risk Assessment (SPRA), approach and results

    International Nuclear Information System (INIS)

    Campbell, R.D.

    1995-01-01

    During the past 15 years there have been over 30 Seismic Probabilistic Risk Assessments (SPRAs) and Seismic Probabilistic Safety Assessments (SPSAs) conducted of Western Nuclear Power Plants, principally of US design. In this paper PRA and PSA are used interchangeably as the overall process is essentially the same. Some similar assessments have been done for reactors in Taiwan, Korea, Japan, Switzerland and Slovenia. These plants were also principally US supplied or built under US license. Since the restructuring of the governments in former Soviet Bloc countries, there has been grave concern regarding the safety of the reactors in these countries. To date there has been considerable activity in conducting partial seismic upgrades but the overall quantification of risk has not been pursued to the depth that it has in Western countries. This paper summarizes the methodology for Seismic PRA/PSA and compares results of two partially completed and two completed PRAs of soviet designed reactors to results from earlier PRAs on US Reactors. A WWER 440 and a WWER 1000 located in low seismic activity regions have completed PRAs and results show the seismic risk to be very low for both designs. For more active regions, partially completed PRAs of a WWER 440 and WWER 1000 located at the same site show the WWER 440 to have much greater seismic risk than the WWER 1000 plant. The seismic risk from the 1000 MW plant compares with the high end of seismic risk for earlier seismic PRAs in the US. Just as for most US plants, the seismic risk appears to be less than the risk from internal events if risk is measured is terms of mean core damage frequency. However, due to the lack of containment for the earlier WWER 440s, the risk to the public may be significantly greater due to the more probable scenario of an early release. The studies reported have not taken the accident sequences beyond the stage of core damage hence the public heath risk ratios are speculative. (author)

  14. Advanced Seismic Probabilistic Risk Assessment Demonstration Project Plan

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, Justin [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-09-01

    Idaho National Laboratories (INL) has an ongoing research and development (R&D) project to remove excess conservatism from seismic probabilistic risk assessments (SPRA) calculations. These risk calculations should focus on providing best estimate results, and associated insights, for evaluation and decision-making. This report presents a plan for improving our current traditional SPRA process using a seismic event recorded at a nuclear power plant site, with known outcomes, to improve the decision making process. SPRAs are intended to provide best estimates of the various combinations of structural and equipment failures that can lead to a seismic induced core damage event. However, in general this approach has been conservative, and potentially masks other important events (for instance, it was not the seismic motions that caused the Fukushima core melt events, but the tsunami ingress into the facility).

  15. Seismic design of nuclear power plants - an assessment

    International Nuclear Information System (INIS)

    Howard, G.E.; Ibanez, P.; Smith, C.B.

    1976-01-01

    This paper presents a review and evaluation of the design standards and the analytical and experimental methods used in the seismic design of nuclear power plants with emphasis on United States practice. Three major areas were investigated: (a) soils, siting, and seismic ground motion specification; (b) soil-structure interaction; and (c) the response of major nuclear power plant structures and components. The purpose of this review and evaluation program was to prepare an independent assessment of the state-of-the-art of the seismic design of nuclear power plants and to identify seismic analysis and design research areas meriting support by the various organizations comprising the 'nuclear power industry'. Criteria used for evaluating the relative importance of alternative research areas included the potential research impact on nuclear power plant siting, design, construction, cost, safety, licensing, and regulation. (Auth.)

  16. Seismic hazard assessment of the Hanford region, Eastern Washington State

    International Nuclear Information System (INIS)

    Youngs, R.R.; Coppersmith, K.J.; Power, M.S.; Swan, F.H. III

    1985-01-01

    A probabilistic seismic hazard assessment was made for a site within the Hanford region of eastern Washington state, which is characterized as an intraplate region having a relatively low rate of seismic activity. Probabilistic procedures, such as logic trees, were utilized to account for the uncertainties in identifying and characterizing the potential seismic sources in the region. Logic trees provide a convenient, flexible means of assessing the values and relative likelihoods of input parameters to the hazard model that may be dependent upon each other. Uncertainties accounted for in this way include the tectonic model, segmentation, capability, fault geometry, maximum earthquake magnitude, and earthquake recurrence rate. The computed hazard results are expressed as a distribution from which confidence levels are assessed. Analysis of the results show the contributions to the total hazard from various seismic sources and due to various earthquake magnitudes. In addition, the contributions of uncertainties in the various source parameters to the uncertainty in the computed hazard are assessed. For this study, the major contribution to uncertainty in the computed hazard are due to uncertainties in the applicable tectonic model and the earthquake recurrence rate. This analysis serves to illustrate some of the probabilistic tools that are available for conducting seismic hazard assessments and for analyzing the results of these studies. 5 references, 7 figures

  17. Probabilistic seismic hazard assessment of southern part of Ghana

    Science.gov (United States)

    Ahulu, Sylvanus T.; Danuor, Sylvester Kojo; Asiedu, Daniel K.

    2018-05-01

    This paper presents a seismic hazard map for the southern part of Ghana prepared using the probabilistic approach, and seismic hazard assessment results for six cities. The seismic hazard map was prepared for 10% probability of exceedance for peak ground acceleration in 50 years. The input parameters used for the computations of hazard were obtained using data from a catalogue that was compiled and homogenised to moment magnitude (Mw). The catalogue covered a period of over a century (1615-2009). The hazard assessment is based on the Poisson model for earthquake occurrence, and hence, dependent events were identified and removed from the catalogue. The following attenuation relations were adopted and used in this study—Allen (for south and eastern Australia), Silva et al. (for Central and eastern North America), Campbell and Bozorgnia (for worldwide active-shallow-crust regions) and Chiou and Youngs (for worldwide active-shallow-crust regions). Logic-tree formalism was used to account for possible uncertainties associated with the attenuation relationships. OpenQuake software package was used for the hazard calculation. The highest level of seismic hazard is found in the Accra and Tema seismic zones, with estimated peak ground acceleration close to 0.2 g. The level of the seismic hazard in the southern part of Ghana diminishes with distance away from the Accra/Tema region to a value of 0.05 g at a distance of about 140 km.

  18. Probabilistic seismic hazard assessment of southern part of Ghana

    Science.gov (United States)

    Ahulu, Sylvanus T.; Danuor, Sylvester Kojo; Asiedu, Daniel K.

    2017-12-01

    This paper presents a seismic hazard map for the southern part of Ghana prepared using the probabilistic approach, and seismic hazard assessment results for six cities. The seismic hazard map was prepared for 10% probability of exceedance for peak ground acceleration in 50 years. The input parameters used for the computations of hazard were obtained using data from a catalogue that was compiled and homogenised to moment magnitude (Mw). The catalogue covered a period of over a century (1615-2009). The hazard assessment is based on the Poisson model for earthquake occurrence, and hence, dependent events were identified and removed from the catalogue. The following attenuation relations were adopted and used in this study—Allen (for south and eastern Australia), Silva et al. (for Central and eastern North America), Campbell and Bozorgnia (for worldwide active-shallow-crust regions) and Chiou and Youngs (for worldwide active-shallow-crust regions). Logic-tree formalism was used to account for possible uncertainties associated with the attenuation relationships. OpenQuake software package was used for the hazard calculation. The highest level of seismic hazard is found in the Accra and Tema seismic zones, with estimated peak ground acceleration close to 0.2 g. The level of the seismic hazard in the southern part of Ghana diminishes with distance away from the Accra/Tema region to a value of 0.05 g at a distance of about 140 km.

  19. Seismic fragility analysis of a nuclear building based on probabilistic seismic hazard assessment and soil-structure interaction analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, R.; Ni, S.; Chen, R.; Han, X.M. [CANDU Energy Inc, Mississauga, Ontario (Canada); Mullin, D. [New Brunswick Power, Point Lepreau, New Brunswick (Canada)

    2016-09-15

    Seismic fragility analyses are conducted as part of seismic probabilistic safety assessment (SPSA) for nuclear facilities. Probabilistic seismic hazard assessment (PSHA) has been undertaken for a nuclear power plant in eastern Canada. Uniform Hazard Spectra (UHS), obtained from the PSHA, is characterized by high frequency content which differs from the original plant design basis earthquake spectral shape. Seismic fragility calculations for the service building of a CANDU 6 nuclear power plant suggests that the high frequency effects of the UHS can be mitigated through site response analysis with site specific geological conditions and state-of-the-art soil-structure interaction analysis. In this paper, it is shown that by performing a detailed seismic analysis using the latest technology, the conservatism embedded in the original seismic design can be quantified and the seismic capacity of the building in terms of High Confidence of Low Probability of Failure (HCLPF) can be improved. (author)

  20. Historical seismicity in France. Its role in the assessment of seismic risk on French nuclear sites

    International Nuclear Information System (INIS)

    Levret, A.

    1987-11-01

    Since 1975 in order to be in conformity with the requirements of the French nuclear program, a review of historical seismicity was undertaken in France. The assessment of seismic hazard for the safety of nuclear plants is in fact based upon a seismotectonic approach which needs to take into account the seismic activity over as long a period of time as possible. The method adopted for reviewing historical earthquakes entails a systematic consultation of the original sources and a critical analysis there of in the light of the historical, geographical and political contexts of the time. The same standards apply where the acquisition of new elements of information is involved. Each item of information is assigned a degree of reliability, then compiled in a computer file, up-dated annually; this file currently contains more than 4.500 events covering a period of time of about a millenary

  1. Structure across the northeastern margin of Flemish Cap, offshore Newfoundland from Erable multichannel seismic reflection profiles: evidence for a transtensional rifting environment

    Science.gov (United States)

    Welford, J. Kim; Hall, Jeremy; Sibuet, Jean-Claude; Srivastava, Shiri P.

    2010-11-01

    We present the results from processing and interpreting nine multichannel seismic reflection lines collected during the 1992 Erable experiment over the northeastern margin of Flemish Cap offshore Newfoundland. These lines, combined into five cross-sections, provide increased seismic coverage over this lightly probed section of the margin and reveal tectonically significant along-strike variations in the degree and compartmentalization of crustal thinning. Similar to the southeastern margins of Flemish Cap and the Grand Banks, a transitional zone of exhumed serpentinized mantle is interpreted between thinned continental and oceanic crust. The 25 km wide transitional zone bears similarities to the 120 km wide transitional zone interpreted as exhumed serpentinized mantle on the conjugate Irish Atlantic margin but the significant width difference is suggestive of an asymmetric conjugate pair. A 40-50 km wide zone of inferred strike-slip shearing is interpreted and observed to extend along most of the northeastern margin of Flemish Cap. Individual shear zones (SZs) may represent extensions of SZs and normal faults within the Orphan Basin providing further evidence for the rotation and displacement of Flemish Cap out of Orphan Basin. The asymmetry between the Flemish Cap and Irish conjugate pairs is likely due in large part to the rotation and displacement of Flemish Cap which resulted in the Flemish Cap margin displaying features of both a strike-slip margin and an extensional margin.

  2. Seismic safety margins research program. Phase I final report - Plant/site selection and data collection (Project I)

    International Nuclear Information System (INIS)

    Chuang, T.Y.

    1981-07-01

    Project I of Phase I of the Seismic Safety Margins Research Program (SSMRP) comprised two parts: the selection of a representative nuclear power plant/site for study in Phase I and the collection of data needed by the other SSMRP projects. Unit 1 of the Zion Nuclear Power Plant in Zion, Illinois, was selected for the SSMRP Phase I studies. Unit 1 of the Zion plant has been validated as a good choice for the Phase I study plant. Although no single nuclear power plant can represent all such plants equally well, selection criteria were developed to maximize the generic implications of Phase I of the SSMRP. On the basis of the selection criteria, the Zion plant and its site were found to be reasonably representative of operating and future plants with regard to its nuclear steam supply system; the type of containment structure (prestressed concrete); its electrical capacity (1100 MWe); its location (the Midwest); the peak seismic acceleration used for design (0.17g); and the properties of the underlying soil (the low-strain shear-wave velocity is 1650 ft/s in a 50- to 100-ft-thick layer of soil overlying sedimentary bedrock). (author)

  3. Seismic safety margins research program. Phase I. Project VII: systems analysis specifications of computational approach

    International Nuclear Information System (INIS)

    Collins, J.D.; Hudson, J.M.; Chrostowski, J.D.

    1979-02-01

    A computational methodology is presented for the prediction of core melt probabilities in a nuclear power plant due to earthquake events. The proposed model has four modules: seismic hazard, structural dynamic (including soil-structure interaction), component failure and core melt sequence. The proposed modules would operate in series and would not have to be operated at the same time. The basic statistical approach uses a Monte Carlo simulation to treat random and systematic error but alternate statistical approaches are permitted by the program design

  4. Development of a shelf margin delta due to uplift of Munkagrunnur Ridge at the margin of Faroe-Shetland Basin: a seismic sequence stratigraphic study

    DEFF Research Database (Denmark)

    Òlavsdóttir, Jana; Boldreel, Lars Ole; Andersen, Moretn S

    2010-01-01

    During the last decade several 3D digital reflection seismic datasets have been acquired in the Faroese sector of the Faroe-Shetland Basin which allow detailed seismic interpretation and mapping of parts of the area. This study presents mapping and seismic sequence stratigraphic interpretation of...

  5. Seismic assessment of Technical Area V (TA-V).

    Energy Technology Data Exchange (ETDEWEB)

    Medrano, Carlos S.

    2014-03-01

    The Technical Area V (TA-V) Seismic Assessment Report was commissioned as part of Sandia National Laboratories (SNL) Self Assessment Requirement per DOE O 414.1, Quality Assurance, for seismic impact on existing facilities at Technical Area-V (TA-V). SNL TA-V facilities are located on an existing Uniform Building Code (UBC) Seismic Zone IIB Site within the physical boundary of the Kirtland Air Force Base (KAFB). The document delineates a summary of the existing facilities with their safety-significant structure, system and components, identifies DOE Guidance, conceptual framework, past assessments and the present Geological and Seismic conditions. Building upon the past information and the evolution of the new seismic design criteria, the document discusses the potential impact of the new standards and provides recommendations based upon the current International Building Code (IBC) per DOE O 420.1B, Facility Safety and DOE G 420.1-2, Guide for the Mitigation of Natural Phenomena Hazards for DOE Nuclear Facilities and Non-Nuclear Facilities.

  6. Seismic rupture study using near-source data: application to seismic hazard assessment

    International Nuclear Information System (INIS)

    Hernandez, Bruno

    2000-01-01

    This work presents seismic source studies using near-field data. In accordance with the quality and the quantity of available data we developed and applied various methods to characterize the seismic source. Macro-seismic data are used to verify if simple and robust methods used on recent instrumental earthquakes may provide a good tool to calibrate historical events in France. These data are often used to characterize earthquakes to be taken into account for seismic hazard assessment in moderate seismicity regions. Geodetic data (SAR, GPS) are used to estimate the slip distribution on the fault during the 1992, Landers, California earthquake. These data are also used to precise the location and the geometry of the main events of the 1997, Colfiorito, central Italy, earthquake sequence. Finally, the strong motions contain the most complete information about rupture process. These data are used to discriminate between two possible fault planes of the 1999, north India, Chamoli earthquake. The strong motions recorded close to the 1999, Mexico, Oaxaca earthquake are used to constrain the rupture history. Strong motions a.re also used in combination with geodetic data to access the rupture history of the Landers earthquake and the main events of the Colfiorito seismic sequence. For the Landers earthquake, the data quality and complementarity offered the possibility to describe the rupture development with accuracy. The large heterogeneities in both slip amplitude and rupture velocity variations suggest that the rupture propagates by breaking successive asperities rather than by propagating like a pulse at constant velocity. The rupture front slows as it encounters barriers and accelerates within main asperities. (author)

  7. Are seismic hazard assessment errors and earthquake surprises unavoidable?

    Science.gov (United States)

    Kossobokov, Vladimir

    2013-04-01

    Why earthquake occurrences bring us so many surprises? The answer seems evident if we review the relationships that are commonly used to assess seismic hazard. The time-span of physically reliable Seismic History is yet a small portion of a rupture recurrence cycle at an earthquake-prone site, which makes premature any kind of reliable probabilistic statements about narrowly localized seismic hazard. Moreover, seismic evidences accumulated to-date demonstrate clearly that most of the empirical relations commonly accepted in the early history of instrumental seismology can be proved erroneous when testing statistical significance is applied. Seismic events, including mega-earthquakes, cluster displaying behaviors that are far from independent or periodic. Their distribution in space is possibly fractal, definitely, far from uniform even in a single segment of a fault zone. Such a situation contradicts generally accepted assumptions used for analytically tractable or computer simulations and complicates design of reliable methodologies for realistic earthquake hazard assessment, as well as search and definition of precursory behaviors to be used for forecast/prediction purposes. As a result, the conclusions drawn from such simulations and analyses can MISLEAD TO SCIENTIFICALLY GROUNDLESS APPLICATION, which is unwise and extremely dangerous in assessing expected societal risks and losses. For example, a systematic comparison of the GSHAP peak ground acceleration estimates with those related to actual strong earthquakes, unfortunately, discloses gross inadequacy of this "probabilistic" product, which appears UNACCEPTABLE FOR ANY KIND OF RESPONSIBLE SEISMIC RISK EVALUATION AND KNOWLEDGEABLE DISASTER PREVENTION. The self-evident shortcomings and failures of GSHAP appeals to all earthquake scientists and engineers for an urgent revision of the global seismic hazard maps from the first principles including background methodologies involved, such that there becomes: (a) a

  8. Material presented to advisory committee on reactor safeguards, subcommittee on extreme external phenomena, January 29-30, 1981, Los Angeles, California. Seismic safety margins research program

    International Nuclear Information System (INIS)

    Smith, P.D.; Bernreuter, D.L.; Bohn, M.P.; Chuang, T.Y.; Cummings, G.E.; Dong, R.G.; Johnson, J.J.; Wells, J.E.

    1981-01-01

    The January 29-30, 1981, meeting of the Advisory Committee on Reactor Safeguards (ACRS), Subcommittee on Extreme External Phenomena, mark the close of Phase I efforts on the Seismic Safety Margins Research Program (SSMRP). Presentations at the meeting focused on results produced. These included computer codes, response computations, failure and release probabilities, data bases, and fragilities and parameter characteristics

  9. Structure and Evolution of the Accretionary Margin of Java-Sumatra. Seismic Data and Numerical Modeling Comparisons.

    Science.gov (United States)

    Kopp, H.; Hindle, D.

    2007-12-01

    We present a numerical model for the evolution of an accretionary prism along a subduction margin. We find the mechanical partitioning of the growing prism into active region, abutting against a deformable backstop, and a relatively undeformed forearc basin is a function of the double tapered basal geometry, where the dip of the detachment is assumed to be opposite above oceanic or continental lithopshere. Varying properties of both materials and detachment can be used to adjust the surface slope and hence geometry of the system, but mechanical partitioning remains essentially the same with the regions becoming broader or narrower. The model appears to closely reproduce the geometry of the Sumatra-Java prism, where a high accretion margin has produced the same distinct mechanical units. Newly prestack depth-migrated marine seismic data reveal the extent and geometry of the active deformation of the deformable backstop, and give indications of some material passing into a subduction channel below the accretionary complex. The deformable backstop appears to be composed of multiple duplex structures, but present day tectonic activity is mostly in the form of transtensive or transpressive deformation, possibly reactivating older dip-slip, accretionary structures. The numerical approach used in the simulation (distinct elements) shows great promise in modelling large deformation in situations such as accretionary prisms, and has also been adapted to incorporate the role of fluid pressure and migration in tandem with large deformation (shortening of the order of 100's of kilometres).

  10. Harmonizing seismic hazard assessments for nuclear power plants

    International Nuclear Information System (INIS)

    Mallard, D.J.

    1993-01-01

    Even a cursory comparison between maps of global seismicity and NPP earthquake design levels reveals many inconsistencies. While, in part, this situation reflects the evolution in understanding of seismic hazards, mismatches can also be due to ongoing differences in the way the hazards are assessed and in local regulatory requirements. So far, formal international consensus has only been able to encompass broad principles, such as those recently recommended by the International Atomic Energy Agency, and even these can raise many technical issues, particularly relating to zones of diffuse seismicity. In the future, greater harmonisation in hazard assessments and, to some extent, in earthquake design levels could emerge through the more widespread use of probabilistic methods. International collaborative ventures and joint projects will be important for resolving anomalies in the existing databases and their interpretations, and for acquiring new data, but to achieve their ideal objectives, they will need to proceed in clearly defined stages. (author)

  11. Crustal Deformation In the Northwestern Margin of the South China Sea: Results From Wide-angle Seismic Modeling

    Science.gov (United States)

    Huang, H.; Klingelhoefer, F.

    2017-12-01

    The South China Sea (SCS) has undergone episodic spreading during the Cenozoic Era. The long-term extension has shaped the continental margins of the SCS, leading to a progressive breakup of the lithosphere. Separated blocks and rift troughs, as controlled by tectonic stretching, contains key information about the deforming mechanism of the crust. In this work, we present a P-wave velocity model of a wide-angle seismic profile OBS2013-1 which passes through the NW margin of the SCS. Modeling of 25 ocean bottom seismometers (OBS) data revealed a detailed crustal structure and shallow complexities along the profile (Figure 1). The crust thins symmetrically across the Xisha Trough, from more than 20 km on flanks to 10 km in the central valley where the sediments thickens over 5 km; A volcano is situated on top of the centre basement high where the Moho drops slightly. At the distal margin around the Zhongsha Trough, the upper crust was detached and accordingly made the middle crust exhumed in a narrow area ( 20 km wide). Meanwhile, materials from the lower crust rises asymmetrically, increasing the crustal velocity by 0.3 km/s and may also giving rise to volcanisms along the hanging side. A 40 km wide hyper-stretched crust (with thickness of 5 km) was identified next to the Zhongsha Trough and covered by overflowing magma and post-rift sediments on the top. These observations argue for a depth-related and asymmetrically extension of the crust, including (1) detachment fault controls the deformation of the upper crust, leading to exhumation of the middle crust and asymmetrically rising of the lower crust, (2) The region adjacent to the exhumation region and with highly thinned crust can be considered as extinct OCT due to magma-starved supplying.

  12. Structural reliability analysis and seismic risk assessment

    International Nuclear Information System (INIS)

    Hwang, H.; Reich, M.; Shinozuka, M.

    1984-01-01

    This paper presents a reliability analysis method for safety evaluation of nuclear structures. By utilizing this method, it is possible to estimate the limit state probability in the lifetime of structures and to generate analytically the fragility curves for PRA studies. The earthquake ground acceleration, in this approach, is represented by a segment of stationary Gaussian process with a zero mean and a Kanai-Tajimi Spectrum. All possible seismic hazard at a site represented by a hazard curve is also taken into consideration. Furthermore, the limit state of a structure is analytically defined and the corresponding limit state surface is then established. Finally, the fragility curve is generated and the limit state probability is evaluated. In this paper, using a realistic reinforced concrete containment as an example, results of the reliability analysis of the containment subjected to dead load, live load and ground earthquake acceleration are presented and a fragility curve for PRA studies is also constructed

  13. How the structural architecture of the Eurasian continental margin affects the structure, seismicity, and topography of the south central Taiwan fold-and-thrust belt

    Science.gov (United States)

    Brown, Dennis; Alvarez-Marron, Joaquina; Biete, Cristina; Kuo-Chen, Hao; Camanni, Giovanni; Ho, Chun-Wei

    2017-07-01

    Studies of mountain belts worldwide show that along-strike changes are common in their foreland fold-and-thrust belts. These are typically caused by processes related to fault reactivation and/or fault focusing along changes in sedimentary sequences. The study of active orogens, like Taiwan, can also provide insights into how these processes influence transient features such as seismicity and topography. In this paper, we trace regional-scale features from the Eurasian continental margin in the Taiwan Strait into the south central Taiwan fold-and-thrust belt. We then present newly mapped surface geology, P wave velocity maps and sections, seismicity, and topography data to test the hypothesis of whether or not these regional-scale features of the margin are contributing to along-strike changes in structural style, and the distribution of seismicity and topography in this part of the Taiwan fold-and-thrust belt. These data show that the most important along-strike change takes place at the eastward prolongation of the upper part of the margin necking zone, where there is a causal link between fault reactivation, involvement of basement in the thrusting, concentration of seismicity, and the formation of high topography. On the area correlated with the necking zone, the strike-slip reactivation of east northeast striking extensional faults is causing sigmoidal offset of structures and topography along two main zones. Here basement is not involved in the thrusting; there is weak focusing of seismicity and localized development of topography. We also show that there are important differences in structure, seismicity, and topography between the margin shelf and its necking zone.

  14. On-line fatigue monitoring and probabilistic assessment of margins

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, I. [Electricite de France, 93 - Saint-Denis (France). Direction des Etudes et Recherches; Morilhat, P. [Electricite de France, 93 - Saint-Denis (France). Direction des Etudes et Recherches

    1995-01-01

    An on-line computer-aided system has been developed by Electricite de France, the French utility, for fatigue monitoring of critical locations in the nuclear steam supply system. This tool, called a fatigue meter, includes as input data plant parameters and is based on some conservative assumptions at several steps of the damage assessment (thermal boundary conditions, stress computation,..). In this paper we present recent developments performed towards a better assessment of margins involved in the complete analysis. The methodology is illustrated with an example showing the influence of uncertainty in plant parameters on the final stress computed at a pressurized water reactor 900MW unit pressurizer surge line nozzle. A second example is shown to illustrate the possibility of defining some transient archetypes. ((orig.)).

  15. Seismic hazard assessment in the Ibero-Maghreb region

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, M.J.; Garcia fernandez, M. [Consejo Superior de Investigaciones Cientifcas, Barcelona (Spain). Inst. of Earth Sciences; GSAHP Ibero-Maghreb Working Group

    1999-12-01

    The paper illustrates the contribution of the Ibero-Maghreb region to the global GSHAP (Global Seismic Hazard Assessment Program) map: for the first time, a map of regional hazard source zones is presented and agreement on a common procedure for hazard computation in the region has been achieved.

  16. Seismic hazard assessment for the Caucasus test area

    Czech Academy of Sciences Publication Activity Database

    Balassanian, S.; Ashirov, T.; Chelidze, T.; Gassanov, A.; Kondorskaya, N.; Molchan, G.; Pustovitenko, B.; Trifonov, V.; Ulomov, V.; Giardini, D.; Erdik, M.; Ghafory-Ashtiany, M.; Grunthal, G.; Mayer-Rosa, D.; Schenk, Vladimír; Stucchi, M.

    1999-01-01

    Roč. 42, č. 6 (1999), s. 1139-1151 ISSN 0365-2556 R&D Projects: GA AV ČR Global Seismic Hazard Assessment Program (GSHAP) - project of the UN International Decade of Natural Disaster Reduction and International Litosphere Program. Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  17. OCT structure, COB location and magmatic type of the S Angolan & SE Brazilian margins from integrated quantitative analysis of deep seismic reflection and gravity anomaly data

    Science.gov (United States)

    Cowie, Leanne; Kusznir, Nick; Horn, Brian

    2014-05-01

    Integrated quantitative analysis using deep seismic reflection data and gravity inversion have been applied to the S Angolan and SE Brazilian margins to determine OCT structure, COB location and magmatic type. Knowledge of these margin parameters are of critical importance for understanding rifted continental margin formation processes and in evaluating petroleum systems in deep-water frontier oil and gas exploration. The OCT structure, COB location and magmatic type of the S Angolan and SE Brazilian rifted continental margins are much debated; exhumed and serpentinised mantle have been reported at these margins. Gravity anomaly inversion, incorporating a lithosphere thermal gravity anomaly correction, has been used to determine Moho depth, crustal basement thickness and continental lithosphere thinning. Residual Depth Anomaly (RDA) analysis has been used to investigate OCT bathymetric anomalies with respect to expected oceanic bathymetries and subsidence analysis has been used to determine the distribution of continental lithosphere thinning. These techniques have been validated for profiles Lusigal 12 and ISE-01 on the Iberian margin. In addition a joint inversion technique using deep seismic reflection and gravity anomaly data has been applied to the ION-GXT BS1-575 SE Brazil and ION-GXT CS1-2400 S Angola deep seismic reflection lines. The joint inversion method solves for coincident seismic and gravity Moho in the time domain and calculates the lateral variations in crustal basement densities and velocities along the seismic profiles. Gravity inversion, RDA and subsidence analysis along the ION-GXT BS1-575 profile, which crosses the Sao Paulo Plateau and Florianopolis Ridge of the SE Brazilian margin, predict the COB to be located SE of the Florianopolis Ridge. Integrated quantitative analysis shows no evidence for exhumed mantle on this margin profile. The joint inversion technique predicts oceanic crustal thicknesses of between 7 and 8 km thickness with

  18. Induced seismicity and carbon storage: Risk assessment and mitigation strategies

    Energy Technology Data Exchange (ETDEWEB)

    White, Joshua A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Foxall, William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bachmann, Corinne [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chiaramonte, Laura [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Daley, Thomas M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-01-28

    Geologic carbon storage (GCS) is widely recognized as an important strategy to reduce atmospheric carbon dioxide (CO2) emissions. Like all technologies, however, sequestration projects create a number of potential environmental and safety hazards that must be addressed. These include earthquakes—from microseismicity to large, damaging events—that can be triggered by altering pore-pressure conditions in the subsurface. To date, measured seismicity due to CO2 injection has been limited to a few modest events, but the hazard exists and must be considered. There are important similarities between CO2 injection and fluid injection from other applications that have induced significant events—e.g. geothermal systems, waste-fluid injection, hydrocarbon extraction, and others. There are also important distinctions among these technologies that should be considered in a discussion of seismic hazard. This report focuses on strategies for assessing and mitigating risk during each phase of a CO2 storage project. Four key risks related to fault reactivation and induced seismicity were considered. Induced slip on faults could potentially lead to: (1) infrastructure damage, (2) a public nuisance, (3) brine-contaminated drinking water, and (4) CO2-contaminated drinking water. These scenarios lead to different types of damage—to property, to drinking water quality, or to the public welfare. Given these four risks, this report focuses on strategies for assessing (and altering) their likelihoods of occurrence and the damage that may result. This report begins with an overview of the basic physical mechanisms behind induced seismicity. This science basis—and its gaps—is crucial because it forms the foundation for risk assessment and mitigation. Available techniques for characterizing and monitoring seismic behavior are also described. Again, this technical basis—and its limitations—must be factored into the risk

  19. Regional relationships among earthquake magnitude scales. Seismic safety margins research program

    International Nuclear Information System (INIS)

    Chung, D.H.; Bernreuter, D.L.

    1980-09-01

    The seismic body-wave magnitude m b of an earthquake is strongly affected by regional variations in the Q structure, composition, and physical state within the earth. Therefore, because of differences in attenuation of P-waves between the western and eastern United States, a problem arises when comparing m b 's for the two regions. A regional m b magnitude bias exists which, depending on where the earthquake occurs and where the P-waves are recorded, can lead to magnitude errors as large as one-third unit. There is also a significant difference between m b and M L values for earthquakes in the western United States. An empirical link between the m b of an eastern U.S. earthquake and the M L of an equivalent western earthquake is given y M L = 0.57 + 0.92(m b ) East . This result is important when comparing ground motion between the two regions and for choosing a set of real western U.S. earthquake records to represent eastern earthquakes. (author)

  20. Seismic assessment of Kozloduy WWER-440, model 230 nuclear power plant

    International Nuclear Information System (INIS)

    Monette, P.; Baltus, R.; Yanev, P.; Campbell, R.

    1993-01-01

    A preliminary report is given of the findings of an IAEA sponsored walkdown of the WWER-440, model 230 at Kozloduy, in May 1991. The scope of the IAEA mission was to determine the lower bound seismic capacity of the plant and to make recommendations for improvements to increase the earthquake resistance. The methodology utilized in the assessment is that used for evaluation of the seismic margin in U.S. nuclear power plants subjected to earthquakes beyond their design basis. Included in the assessment is the establishment of a safe shutdown path which would include the capacity to mitigate a small break in the primary system, performance of a walkdown of the safe shutdown path and calculation of the high-confidence-of-low-probability-of-failure (HCLPF) of the safe shutdown path. Excluding system design deficiency relative to U.S. and Western Europe standards, it was found that the plant has many seismic vulnerabilities similar to those that existed in many of the U.S. plants prior to about 1979 when the Systematic Evaluation Program was initiated. (Z.S.) 1 tab., 1 fig

  1. A methodology for assessment seismic risk in PSAs

    International Nuclear Information System (INIS)

    Jae, Moo Sung

    2001-01-01

    This paper suggested a new framework for assessing seismic risk in PSAs. The framework used the concepts of requirement and achievement in the reliability physics. The quantified correlation which is a function of the requirement variable (hazard curve) and the achievement variable (fragility curve) results in a quantity, the unconditional frequency of exceeding a damage lelvel. This framework can be applied to any other external safety assessment, such as Fire and Flood Risk in PSAs

  2. Assessing seismic adequacy of existing nuclear power plant structures

    International Nuclear Information System (INIS)

    Belyaev, V.; Vinogradov, V.; Privalov, S.; Shishenin, V.

    2003-01-01

    Nowadays Russia's specialists perform a huge amount of works to revaluate the NPP safety. These works are certain to include refinement of NPP safety assessment under the effects of specific dynamic loads, earthquake effects included. It should be noted, that a number of Russian NPPs now in operation had been designed either with no account of these loads, or under the requirements which are underestimated as compared with the modern requirements on the external load composition and rate. Revaluation of NPP seismic safety is based on the results of the works taken under orderly sequence on assessment of (1) seismic input and ground effects; (2) structure response and state; (3) equipment and pipelines response and state. The paper considers the methods of NPP structures response and state assessment. Therewith we assume that ground motion predicted behavior at the construction basement has been preset for the SSE and OBE conditions and the effects of soil-structure interaction, including the situation of possible soft soil liquefaction. Necessity to determine both the reaction of a construction and its state as a whole as well as its elements reaction, to evaluate their bearing capacity and destruction zones formation makes it necessary to make up a detailed structural model, which is usually a finite element one. Since seismic revaluation is to be performed for the existing structures, characteristics of which can substantially differ from the design ones, revealing the actual state of this structures becomes critical. If the real values of physical and mechanical properties of the structure materials, connections of elements etc. are used as initial data in a structural model this permits to increase the design assessment credibility and reliability substantially. The paper analyzes the results of determining these initial assessments while inspecting several Russian NPPs on the basis of a 'combined' method. This method is realized at two consecutive stages. The

  3. Seismic Risk Assessment and Loss Estimation for Tbilisi City

    Science.gov (United States)

    Tsereteli, Nino; Alania, Victor; Varazanashvili, Otar; Gugeshashvili, Tengiz; Arabidze, Vakhtang; Arevadze, Nika; Tsereteli, Emili; Gaphrindashvili, Giorgi; Gventcadze, Alexander; Goguadze, Nino; Vephkhvadze, Sophio

    2013-04-01

    The proper assessment of seismic risk is of crucial importance for society protection and city sustainable economic development, as it is the essential part to seismic hazard reduction. Estimation of seismic risk and losses is complicated tasks. There is always knowledge deficiency on real seismic hazard, local site effects, inventory on elements at risk, infrastructure vulnerability, especially for developing countries. Lately great efforts was done in the frame of EMME (earthquake Model for Middle East Region) project, where in the work packages WP1, WP2 , WP3 and WP4 where improved gaps related to seismic hazard assessment and vulnerability analysis. Finely in the frame of work package wp5 "City Scenario" additional work to this direction and detail investigation of local site conditions, active fault (3D) beneath Tbilisi were done. For estimation economic losses the algorithm was prepared taking into account obtained inventory. The long term usage of building is very complex. It relates to the reliability and durability of buildings. The long term usage and durability of a building is determined by the concept of depreciation. Depreciation of an entire building is calculated by summing the products of individual construction unit' depreciation rates and the corresponding value of these units within the building. This method of calculation is based on an assumption that depreciation is proportional to the building's (constructions) useful life. We used this methodology to create a matrix, which provides a way to evaluate the depreciation rates of buildings with different type and construction period and to determine their corresponding value. Finally loss was estimated resulting from shaking 10%, 5% and 2% exceedance probability in 50 years. Loss resulting from scenario earthquake (earthquake with possible maximum magnitude) also where estimated.

  4. Crustal structure variations along the NW-African continental margin: A comparison of new and existing models from wide-angle and reflection seismic data

    Science.gov (United States)

    Klingelhoefer, Frauke; Biari, Youssef; Sahabi, Mohamed; Aslanian, Daniel; Schnabel, Michael; Matias, Luis; Benabdellouahed, Massinissa; Funck, Thomas; Gutscher, Marc-André; Reichert, Christian; Austin, James A.

    2016-04-01

    Deep seismic data represent a key to understand the geometry and mechanism of continental rifting. The passive continental margin of NW-Africa is one of the oldest on earth, formed during the Upper Triassic-Lower Liassic rifting of the central Atlantic Ocean over 200 Ma. We present new and existing wide-angle and reflection seismic data from four study regions along the margin located in the south offshore DAKHLA, on the central continental margin offshore Safi, in the northern Moroccan salt basin, and in the Gulf of Cadiz. The thickness of unthinned continental crust decreases from 36 km in the North to about 27 km in the South. Crustal thinning takes place over a region of 150 km in the north and only 70 km in the south. The North Moroccan Basin is underlain by highly thinned continental crust of only 6-8 km thickness. The ocean-continent transition zone shows a variable width between 40 and 70 km and is characterized by seismic velocities in between those of typical oceanic and thinned continental crust. The neighbouring oceanic crust is characterized by a thickness of 7-8 km along the complete margin. Relatively high velocities of up to 7.5 km/s have been imaged between magnetic anomalies S1 and M25, and are probably related to changes in the spreading velocities at the time of the Kimmeridgian/Tithonian plate reorganization. Volcanic activity seems to be mostly confined to the region next to the Canary Islands, and is thus not related to the initial opening of the ocean, which was associated to only weak volcanism. Comparison with the conjugate margin off Nova Scotia shows comparable continental crustal structures, but 2-3 km thinner oceanic crust on the American side than on the African margin.

  5. Assessment of seismic damages in nuclear power plant buildings

    International Nuclear Information System (INIS)

    Corsanego, A.; DelGrosso, A.; Ferro, G.

    1987-01-01

    Performance of nuclear power plant sites, buildings and components is in today's practice continuously evaluated by means of monitoring systems composed by a variety of instruments, allowing records of the most significant behavioral parameters to be gathered by electronic data acquisition equipment. A great emphasis has been devoted in recent years to the development of ''intelligent'' monitoring systems able to perform interpretation of the response of structures and components automatically, only requiring human intervention and sophisticated data processing techniques when degradation of the safety margins is likely to have been produced. Such computerized procedures can be formulated through logic or algorithmic processes and normally are consistently based upon simplified, heuristic behavioral models and probabilistic reasoning schemes. This paper is devoted to discuss the development of an algorithmic procedure intended for automatic, real-time interpretation of the recorded response of nuclear power plant buildings and foundations during seismic events

  6. Seismic design margin evaluation of systems and equipment required for safe shutdown of North Anna, Units 1 and 2, following an SSE (safe-shutdown earthquake) event. Technical report

    International Nuclear Information System (INIS)

    Desai, K.D.

    1981-06-01

    The Advisory Committee on Reactor Safeguards recommended that the NRC staff review in detail the capability and available seismic design margin of fluid systems and equipment used in North Anna, Units 1 and 2 to achieve safe shutdown following a site-design safe-shutdown earthquake (SSE). The staff conducted a series of plant visits and meetings with the licensee to view and discuss the seismic design methodology used for systems, equipment and their supports. The report is a description and evaluation of the seismic design criteria, design conservatisms and seismic design margin for North Anna, Units 1 and 2

  7. The Global Seismic Hazard Assessment Program (GSHAP - 1992/1999

    Directory of Open Access Journals (Sweden)

    D. Giardini

    1999-06-01

    Full Text Available The United Nations, recognizing natural disasters as a major threat to human life and development, designed the 1990-1999 period as the International Decade for Natural Disaster Reduction (UN/IDNDR; UN Res. 42/169/ 1987. Among the IDNDR Demonstration Projects is the Global Seismic Hazard Assessment Program (GSHAP, launched in 1992 by the International Lithosphere Program (ILP and implemented in the 1992-1999 period. In order to mitigate the risk associated to the recurrence of earthquakes, the GSHAP promoted a regionally coordinated, homogeneous approach to seismic hazard evaluation. To achieve a global dimension, the GSHAP established initially a mosaic of regions and multinational test areas, then expanded to cover whole continents and finally the globe. The GSHAP Global Map of Seismic Hazard integrates the results obtained in the regional areas and depicts Peak-Ground-Acceleration (PGA with 10% chance of exceedance in 50 years, corresponding to a return period of 475 years. All regional results and the Global Map of Seismic Hazard are published in 1999 and available on the GSHAP homepage on http://seismo.ethz.ch/GSHAP/.

  8. Assessment of Biomass Resources from Marginal Lands in APEC Economies

    Energy Technology Data Exchange (ETDEWEB)

    Milbrandt, A.; Overend, R. P.

    2009-08-01

    The goal of this study is to examine the marginal lands in Asia-Pacific Economic Cooperation (APEC) economies and evaluate their biomass productivity potential. Twelve categories of marginal lands are identified using the Global Agro-Ecological Zones system of the United Nations Food and Agriculture Organization.

  9. Seismic hazard assessment for Guam and the Northern Mariana Islands

    Science.gov (United States)

    Mueller, Charles S.; Haller, Kathleen M.; Luco, Nicholas; Petersen, Mark D.; Frankel, Arthur D.

    2012-01-01

    We present the results of a new probabilistic seismic hazard assessment for Guam and the Northern Mariana Islands. The Mariana island arc has formed in response to northwestward subduction of the Pacific plate beneath the Philippine Sea plate, and this process controls seismic activity in the region. Historical seismicity, the Mariana megathrust, and two crustal faults on Guam were modeled as seismic sources, and ground motions were estimated by using published relations for a firm-rock site condition. Maps of peak ground acceleration, 0.2-second spectral acceleration for 5 percent critical damping, and 1.0-second spectral acceleration for 5 percent critical damping were computed for exceedance probabilities of 2 percent and 10 percent in 50 years. For 2 percent probability of exceedance in 50 years, probabilistic peak ground acceleration is 0.94 gravitational acceleration at Guam and 0.57 gravitational acceleration at Saipan, 0.2-second spectral acceleration is 2.86 gravitational acceleration at Guam and 1.75 gravitational acceleration at Saipan, and 1.0-second spectral acceleration is 0.61 gravitational acceleration at Guam and 0.37 gravitational acceleration at Saipan. For 10 percent probability of exceedance in 50 years, probabilistic peak ground acceleration is 0.49 gravitational acceleration at Guam and 0.29 gravitational acceleration at Saipan, 0.2-second spectral acceleration is 1.43 gravitational acceleration at Guam and 0.83 gravitational acceleration at Saipan, and 1.0-second spectral acceleration is 0.30 gravitational acceleration at Guam and 0.18 gravitational acceleration at Saipan. The dominant hazard source at the islands is upper Benioff-zone seismicity (depth 40–160 kilometers). The large probabilistic ground motions reflect the strong concentrations of this activity below the arc, especially near Guam.

  10. Cracking pattern and seismic performance assessment of the Orvieto cathedral

    International Nuclear Information System (INIS)

    De Canio, G.

    2015-01-01

    In this paper are described the in situ cracking pattern measurement and ambient vibration monitoring for the seismic performance evaluation of the Orvieto Cathedral Italy, according the deplacement based safety assessment. This requires, as a first step, the direct measurement of the cracking pattern and dynamic response of the structural macro elements of the cathedral due to weak vibrations induced by traffic and seismic micro tremors. Seismic assessment for this type of structure require also the proper limit states definitions. In fact, in the case historic monuments like churches, due to the presence of specific typology of macro elements: rigid blocks, complex vault systems, slenderness of the walls, presence of wide halls, domes and drums with particular geometry, is necessary to define the proper assessment procedures which are slightly different with respect those required for conventional civil industrial buildings. Regarding the Ambient vibration monitoring, a new approach to estimate the participating masses associated to the macro element kinematics is defined: it is based on the frequency contribution to the Root Main Square Acceleration, obtained by numerical integration of the Power Spectral Density (PSD) function. This information, when associated to the analysis of the Real and Imaginary part of the Cross Spectral Density (CSD) function between the acceleration time histories at different points, allow to identify the principal (at least first and second) mode shapes of the structure.

  11. A GIS approach to seismic risk assessment with an application to mining-related seismicity in Johannesburg, South Africa

    Science.gov (United States)

    Liebenberg, Keagen; Smit, Ansie; Coetzee, Serena; Kijko, Andrzej

    2017-08-01

    The majority of seismic activity in South Africa is related to extensive mining operations, usually in close proximity to densely populated areas where a relatively weak seismic event could cause damage. Despite a significant decrease in mining operations in the Witwatersrand area, the number of seismic events appears to be increasing and is attributed to the acid mine drainage problem. The increased seismicity is raising concern amongst disaster management centres and in the insurance industry. A better understanding is required of the vulnerability and the size of the potential loss of people and infrastructure in densely populated Johannesburg and its surrounding areas. Results of a deterministic seismic risk, vulnerability, and loss assessment are presented by making use of a geographic information system (GIS). The results illustrate the benefits of using GIS and contribute to a better understanding of the risk, which can assist in improving disaster preparedness.

  12. Soil structure interaction analysis for the US NRC seismic safety margins research program

    International Nuclear Information System (INIS)

    Johnson, J.J.

    1979-01-01

    The soil structure interaction project is described. The initial portion of this task concentrates on defining the state-of-the-art in the analysis of the soil structure interaction phenomenon, an assessment of those aspects of the phenomenon which significantly affect structural response, and recommendations for future development of analytical techniques and their verification. A series of benchmark analytical and test problems for which analytical techniques may be evaluated are also sought. This assessment is to be performed in the context of nuclear power plant structures; i.e., massive stiff structures arranged functionally on a particular site. The best estimate methodology will be utilized to develop transfer functions for the overall systems model. These transfer functions will operate on the free-field ground motion yielding the structural base mat response and selected in-structure response quantities for the particular site being analyzed. The transfer functions will depend on a number of parameters, e.g., soil configuration, soil material properties, frequency of the excitation, structural properties, etc. A limited comparison of alternative methods of analysis including a nonlinear analysis will be performed

  13. Level-1 seismic probabilistic risk assessment for a PWR plant

    International Nuclear Information System (INIS)

    Kondo, Keisuke; Nishio, Masahide; Fujimoto, Haruo; Ichitsuka, Akihiro

    2014-01-01

    In Japan, revised Seismic Design Guidelines for the domestic light water reactors was published on September 19, 2006. These new guidelines have introduced the purpose to confirm that residual risk resulting from earthquake that exceeds the design limit seismic ground motion (Ss) is sufficiently small, based on the probabilistic risk assessment (PRA) method, in addition to conventional deterministic design base methodology. In response to this situation, JNES had been working to improve seismic PRA (SPRA) models for individual domestic light water reactors. In case of PWR in Japan, total of 24 plants were grouped into 11 categories to develop individual SPRA model. The new regulatory rules against the Fukushima dai-ichi nuclear power plants' severe accidents occurred on March 11, 2011, are going to be enforced in July 2013 and utilities are necessary to implement additional safety measures to avoid and mitigate severe accident occurrence due to external events such as earthquake and tsunami, by referring to the results of severe accident study including SPRA. In this paper a SPRA model development for a domestic 3-loop PWR plant as part of the above-mentioned 11 categories is described. We paid special attention to how to categorize initiating events that are specific to seismic phenomena and how to confirm the effect of the simultaneous failure probability calculation model for the multiple components on the result of core damage frequency evaluation. Simultaneous failure probability for multiple components has been evaluated by power multiplier method. Then tentative level-1 seismic probabilistic risk assessment (SPRA) has been performed by the developed SPSA model with seismic hazard and fragility data. The base case was evaluated under the condition with calculated fragility data and conventional power multiplier. The difference in CDF between the case of conventional power multiplier and that of power multiplier=1 (complete dependence) was estimated to be

  14. A Methodology for Assessing the Seismic Vulnerability of Highway Systems

    International Nuclear Information System (INIS)

    Cirianni, Francis; Leonardi, Giovanni; Scopelliti, Francesco

    2008-01-01

    Modern society is totally dependent on a complex and articulated infrastructure network of vital importance for the existence of the urban settlements scattered on the territory. On these infrastructure systems, usually indicated with the term lifelines, are entrusted numerous services and indispensable functions of the normal urban and human activity.The systems of the lifelines represent an essential element in all the urbanised areas which are subject to seismic risk. It is important that, in these zones, they are planned according to opportune criteria based on two fundamental assumptions: a) determination of the best territorial localization, avoiding, within limits, the places of higher dangerousness; b) application of constructive technologies finalized to the reduction of the vulnerability.Therefore it is indispensable that in any modern process of seismic risk assessment the study of the networks is taken in the rightful consideration, to be integrated with the traditional analyses of the buildings.The present paper moves in this direction, dedicating particular attention to one kind of lifeline: the highway system, proposing a methodology of analysis finalized to the assessment of the seismic vulnerability of the system

  15. Rapid Assessment of Seismic Vulnerability in Palestinian Refugee Camps

    Science.gov (United States)

    Al-Dabbeek, Jalal N.; El-Kelani, Radwan J.

    Studies of historical and recorded earthquakes in Palestine demonstrate that damaging earthquakes are occurring frequently along the Dead Sea Transform: Earthquake of 11 July 1927 (ML 6.2), Earthquake of 11 February 2004 (ML 5.2). In order to reduce seismic vulnerability of buildings, losses in lives, properties and infrastructures, an attempt was made to estimate the percentage of damage degrees and losses at selected refugee camps: Al Ama`ri, Balata and Dhaishe. Assessing the vulnerability classes of building structures was carried out according to the European Macro-Seismic Scale 1998 (EMS-98) and the Fedral Emergency Management Agency (FEMA). The rapid assessment results showed that very heavy structural and non structural damages will occur in the common buildings of the investigated Refugee Camps (many buildings will suffer from damages grades 4 and 5). Bad quality of buildings in terms of design and construction, lack of uniformity, absence of spaces between the building and the limited width of roads will definitely increase the seismic vulnerability under the influence of moderate-strong (M 6-7) earthquakes in the future.

  16. A Framework for Understanding Uncertainty in Seismic Risk Assessment.

    Science.gov (United States)

    Foulser-Piggott, Roxane; Bowman, Gary; Hughes, Martin

    2017-10-11

    A better understanding of the uncertainty that exists in models used for seismic risk assessment is critical to improving risk-based decisions pertaining to earthquake safety. Current models estimating the probability of collapse of a building do not consider comprehensively the nature and impact of uncertainty. This article presents a model framework to enhance seismic risk assessment and thus gives decisionmakers a fuller understanding of the nature and limitations of the estimates. This can help ensure that risks are not over- or underestimated and the value of acquiring accurate data is appreciated fully. The methodology presented provides a novel treatment of uncertainties in input variables, their propagation through the model, and their effect on the results. The study presents ranges of possible annual collapse probabilities for different case studies on buildings in different parts of the world, exposed to different levels of seismicity, and with different vulnerabilities. A global sensitivity analysis was conducted to determine the significance of uncertain variables. Two key outcomes are (1) that the uncertainty in ground-motion conversion equations has the largest effect on the uncertainty in the calculation of annual collapse probability; and (2) the vulnerability of a building appears to have an effect on the range of annual collapse probabilities produced, i.e., the level of uncertainty in the estimate of annual collapse probability, with less vulnerable buildings having a smaller uncertainty. © 2017 Society for Risk Analysis.

  17. Seismic and Restoration Assessment of Monumental Masonry Structures

    Directory of Open Access Journals (Sweden)

    Panagiotis G. Asteris

    2017-08-01

    Full Text Available Masonry structures are complex systems that require detailed knowledge and information regarding their response under seismic excitations. Appropriate modelling of a masonry structure is a prerequisite for a reliable earthquake-resistant design and/or assessment. However, modelling a real structure with a robust quantitative (mathematical representation is a very difficult, complex and computationally-demanding task. The paper herein presents a new stochastic computational framework for earthquake-resistant design of masonry structural systems. The proposed framework is based on the probabilistic behavior of crucial parameters, such as material strength and seismic characteristics, and utilizes fragility analysis based on different failure criteria for the masonry material. The application of the proposed methodology is illustrated in the case of a historical and monumental masonry structure, namely the assessment of the seismic vulnerability of the Kaisariani Monastery, a byzantine church that was built in Athens, Greece, at the end of the 11th to the beginning of the 12th century. Useful conclusions are drawn regarding the effectiveness of the intervention techniques used for the reduction of the vulnerability of the case-study structure, by means of comparison of the results obtained.

  18. Seismic and Restoration Assessment of Monumental Masonry Structures

    Science.gov (United States)

    Asteris, Panagiotis G.; Douvika, Maria G.; Apostolopoulou, Maria; Moropoulou, Antonia

    2017-01-01

    Masonry structures are complex systems that require detailed knowledge and information regarding their response under seismic excitations. Appropriate modelling of a masonry structure is a prerequisite for a reliable earthquake-resistant design and/or assessment. However, modelling a real structure with a robust quantitative (mathematical) representation is a very difficult, complex and computationally-demanding task. The paper herein presents a new stochastic computational framework for earthquake-resistant design of masonry structural systems. The proposed framework is based on the probabilistic behavior of crucial parameters, such as material strength and seismic characteristics, and utilizes fragility analysis based on different failure criteria for the masonry material. The application of the proposed methodology is illustrated in the case of a historical and monumental masonry structure, namely the assessment of the seismic vulnerability of the Kaisariani Monastery, a byzantine church that was built in Athens, Greece, at the end of the 11th to the beginning of the 12th century. Useful conclusions are drawn regarding the effectiveness of the intervention techniques used for the reduction of the vulnerability of the case-study structure, by means of comparison of the results obtained. PMID:28767073

  19. On the importance of uncertain factors in seismic fragility assessment

    International Nuclear Information System (INIS)

    Borgonovo, E.; Zentner, I.; Pellegri, A.; Tarantola, S.; Rocquigny, E. de

    2013-01-01

    This paper addresses the definition of importance measures for helping the modeller to detect the factors on which to focus modelling activity and data collection in seismic fragility analysis. We study sensitivity measures consistent with the decision-support criteria of interest, namely, the (mean) fragility curve and the “High Confidence of Low Probability of Failure” (HCLPF) value. The importance measures are obtained analytically for the EPRI safety factor method, which is nowadays used worldwide for seismic risk assessment of nuclear plants. We illustrate and discuss the use of both variance-based and CDF-based importance measures in the application to two case studies, the first analytical and based on the EPRI method, the second numerical.

  20. Review on Rapid Seismic Vulnerability Assessment for Bulk of Buildings

    Science.gov (United States)

    Nanda, R. P.; Majhi, D. R.

    2013-09-01

    This paper provides a brief overview of rapid visual screening (RVS) procedures available in different countries with a comparison among all the methods. Seismic evaluation guidelines from, USA, Canada, Japan, New Zealand, India, Europe, Italy, UNDP, with other methods are reviewed from the perspective of their applicability to developing countries. The review shows clearly that some of the RVS procedures are unsuited for potential use in developing countries. It is expected that this comparative assessment of various evaluation schemes will help to identify the most essential components of such a procedure for use in India and other developing countries, which is not only robust, reliable but also easy to use with available resources. It appears that Federal Emergency Management Agency (FEMA) 154 and New Zealand Draft Code approaches can be suitably combined to develop a transparent, reasonably rigorous and generalized procedure for seismic evaluation of buildings in developing countries.

  1. OCT structure, COB location and magmatic type of the SE Brazilian & S Angolan margins from integrated quantitative analysis of deep seismic reflection and gravity anomaly data

    Science.gov (United States)

    Cowie, L.; Kusznir, N. J.; Horn, B.

    2013-12-01

    Knowledge of ocean-continent transition (OCT) structure, continent-ocean boundary (COB) location and magmatic type are of critical importance for understanding rifted continental margin formation processes and in evaluating petroleum systems in deep-water frontier oil and gas exploration. The OCT structure, COB location and magmatic type of the SE Brazilian and S Angolan rifted continental margins are much debated; exhumed and serpentinised mantle have been reported at these margins. Integrated quantitative analysis using deep seismic reflection data and gravity inversion have been used to determine OCT structure, COB location and magmatic type for the SE Brazilian and S Angolan margins. Gravity inversion has been used to determine Moho depth, crustal basement thickness and continental lithosphere thinning. Residual Depth Anomaly (RDA) analysis has been used to investigate OCT bathymetric anomalies with respect to expected oceanic bathymetries and subsidence analysis has been used to determine the distribution of continental lithosphere thinning. These techniques have been validated on the Iberian margin for profiles IAM9 and ISE-01. In addition a joint inversion technique using deep seismic reflection and gravity anomaly data has been applied to the ION-GXT BS1-575 SE Brazil and ION-GXT CS1-2400 S Angola. The joint inversion method solves for coincident seismic and gravity Moho in the time domain and calculates the lateral variations in crustal basement densities and velocities along profile. Gravity inversion, RDA and subsidence analysis along the S Angolan ION-GXT CS1-2400 profile has been used to determine OCT structure and COB location. Analysis suggests that exhumed mantle, corresponding to a magma poor margin, is absent beneath the allochthonous salt. The thickness of earliest oceanic crust, derived from gravity and deep seismic reflection data is approximately 7km. The joint inversion predicts crustal basement densities and seismic velocities which are

  2. Risk assessment to determine the advisability of seismic trip systems

    International Nuclear Information System (INIS)

    Cummings, G.E.; Wells, J.E.

    1977-01-01

    Seismic trip (scram) systems have been used for many years on certain research, test, and production reactors, but not on commercial power reactors. An assessment is made of the risks associated with the presence and absence of such trip systems on power reactors. An attempt was made to go beyond the reactor per se and to consider the risks to society as a whole; for example, the advantages of tripping to avoid an earthquake-caused accident were weighed against the disadvantages associated with interrupting electric power in a time when it would be needed for emergency services. The comparative risk assessment was performed by means of fault tree analysis

  3. New interpretations based on seismic and modelled well data and their implications for the tectonic evolution of the west Greenland continental margin

    DEFF Research Database (Denmark)

    Mcgregor, E.D.; Nielsen, S.B.; Stephenson, R.A.

    Davis Strait is situated between Baffin Island and Greenland and forms part of a sedimentary basin system, linking Labrador Sea and Baffin Bay, developed during Cretaceous and Palaeocene rifting that culminated in a brief period of sea-floor spreading in the late Palaeocene and Eocene. Seismic...... reflection profiles and exploration wells along the Greenland margin of Davis Strait have been analysed in order to elucidate uplift events affecting sedimentary basin development during the Cenozoic with a focus on postulated Neogene (tectonic) uplift affecting the west Greenland continental margin...... tectonic event. An interpretation in which the inferred onshore cooling is related to erosion of pre-existing topography is more consistent with our new results from the offshore region. These results will have important implications for other continental margins developed throughout the Atlantic...

  4. Proceedings of the Specialist Meeting on the Seismic Probabilistic Safety Assessment of Nuclear Facilities

    International Nuclear Information System (INIS)

    2007-01-01

    The main objectives of the Meeting were to review recent advances in the methodology of Seismic Probabilistic Safety Assessment (SPSA), to discuss practical applications, to review the current state of the art, and to identify methodological issues where further research would be beneficial in enhancing the usefulness of the methodology. Applications of the Seismic Margin Assessment methodology (SMA), a methodology related to SPSA, were also discussed. One specific objective was to compare the situation today with the situation at the time of the 1999 Tokyo workshop, and to develop a set of findings and recommendations that would update those from that earlier workshop. There was a consensus at the Specialists Meeting that SPSA is now in widespread use throughout the nuclear-power industry worldwide, by the operating nuclear power plants (NPPs) themselves, by the various national regulatory agencies, and by the designers of new NPPs. It was also widely agreed that it can systematically accomplish several very important objectives; specifically, it can contribute: - To understanding the seismic risk arising from NPPs. - To understanding the safety significance of seismic design shortfalls. - To prioritizing seismic safety improvements. - To evaluating and improving seismic regulations. - To modifying the seismic regulatory/licensing basis of an individual NPP. Compared to the situation in 1999, when the first Workshop was held in Tokyo, there have been significant expansions in the use of SPSA in many different areas. Some countries provided detailed information on their regulatory framework for using seismic PSA. Many other countries also provided some information in their papers as background for conducting SPSA. During the Meeting, a small number of important weaknesses in SPSA methodology were identified. None of these are new, all having been widely recognized for many years. However, for some of the weaknesses, extensive discussions during the Meeting provided

  5. Proceedings of the Specialist Meeting on the Seismic Probabilistic Safety Assessment of Nuclear Facilities

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-11-14

    The main objectives of the Meeting were to review recent advances in the methodology of Seismic Probabilistic Safety Assessment (SPSA), to discuss practical applications, to review the current state of the art, and to identify methodological issues where further research would be beneficial in enhancing the usefulness of the methodology. Applications of the Seismic Margin Assessment methodology (SMA), a methodology related to SPSA, were also discussed. One specific objective was to compare the situation today with the situation at the time of the 1999 Tokyo workshop, and to develop a set of findings and recommendations that would update those from that earlier workshop. There was a consensus at the Specialists Meeting that SPSA is now in widespread use throughout the nuclear-power industry worldwide, by the operating nuclear power plants (NPPs) themselves, by the various national regulatory agencies, and by the designers of new NPPs. It was also widely agreed that it can systematically accomplish several very important objectives; specifically, it can contribute: - To understanding the seismic risk arising from NPPs. - To understanding the safety significance of seismic design shortfalls. - To prioritizing seismic safety improvements. - To evaluating and improving seismic regulations. - To modifying the seismic regulatory/licensing basis of an individual NPP. Compared to the situation in 1999, when the first Workshop was held in Tokyo, there have been significant expansions in the use of SPSA in many different areas. Some countries provided detailed information on their regulatory framework for using seismic PSA. Many other countries also provided some information in their papers as background for conducting SPSA. During the Meeting, a small number of important weaknesses in SPSA methodology were identified. None of these are new, all having been widely recognized for many years. However, for some of the weaknesses, extensive discussions during the Meeting provided

  6. Seismic reliability assessment methodology for CANDU concrete containment structures-phase 11

    International Nuclear Information System (INIS)

    Hong, H.P.

    1996-07-01

    This study was undertaken to verify a set of load factors for reliability-based seismic evaluation of CANDU containment structures in Eastern Canada. Here, the new, site-specific, results of probabilistic seismic hazard assessment (response spectral velocity) were applied. It was found that the previously recommended load factors are relatively insensitive to the new seismic hazard information, and are adequate for a reliability-based seismic evaluation process. (author). 4 refs., 5 tabs., 9 figs

  7. Preliminary seismic design cost-benefit assessment of the tuff repository waste-handling facilities

    International Nuclear Information System (INIS)

    Subramanian, C.V.; Abrahamson, N.; Hadjian, A.H.

    1989-02-01

    This report presents a preliminary assessment of the costs and benefits associated with changes in the seismic design basis of waste-handling facilities. The objectives of the study are to understand the capability of the current seismic design of the waste-handling facilities to mitigate seismic hazards, evaluate how different design levels and design measures might be used toward mitigating seismic hazards, assess the costs and benefits of alternative seismic design levels, and develop recommendations for possible modifications to the seismic design basis. This preliminary assessment is based primarily on expert judgment solicited in an interdisciplinary workshop environment. The estimated costs for individual attributes and the assumptions underlying these cost estimates (seismic hazard levels, fragilities, radioactive-release scenarios, etc.) are subject to large uncertainties, which are generally identified but not treated explicitly in this preliminary analysis. The major conclusions of the report do not appear to be very sensitive to these uncertainties. 41 refs., 51 figs., 35 tabs

  8. Time-Independent Annual Seismic Rates, Based on Faults and Smoothed Seismicity, Computed for Seismic Hazard Assessment in Italy

    Science.gov (United States)

    Murru, M.; Falcone, G.; Taroni, M.; Console, R.

    2017-12-01

    In 2015 the Italian Department of Civil Protection, started a project for upgrading the official Italian seismic hazard map (MPS04) inviting the Italian scientific community to participate in a joint effort for its realization. We participated providing spatially variable time-independent (Poisson) long-term annual occurrence rates of seismic events on the entire Italian territory, considering cells of 0.1°x0.1° from M4.5 up to M8.1 for magnitude bin of 0.1 units. Our final model was composed by two different models, merged in one ensemble model, each one with the same weight: the first one was realized by a smoothed seismicity approach, the second one using the seismogenic faults. The spatial smoothed seismicity was obtained using the smoothing method introduced by Frankel (1995) applied to the historical and instrumental seismicity. In this approach we adopted a tapered Gutenberg-Richter relation with a b-value fixed to 1 and a corner magnitude estimated with the bigger events in the catalogs. For each seismogenic fault provided by the Database of the Individual Seismogenic Sources (DISS), we computed the annual rate (for each cells of 0.1°x0.1°) for magnitude bin of 0.1 units, assuming that the seismic moments of the earthquakes generated by each fault are distributed according to the same tapered Gutenberg-Richter relation of the smoothed seismicity model. The annual rate for the final model was determined in the following way: if the cell falls within one of the seismic sources, we merge the respective value of rate determined by the seismic moments of the earthquakes generated by each fault and the value of the smoothed seismicity model with the same weight; if instead the cells fall outside of any seismic source we considered the rate obtained from the spatial smoothed seismicity. Here we present the final results of our study to be used for the new Italian seismic hazard map.

  9. Seismic assessment of air-cooled type emergency electric power supply system

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    JNES initiated seismic assessment programs to develop seismic review criterions for the air-cooled system (diesel generator, gas turbine generator), which will be newly installed for enhancing the diversity of emergency electric power supply system. Five principal subjects are involved in the programs: two subjects for fiscal 2011 and three ones for fiscal 2012 and 2013. The summary of outcomes is as follows: 1) Past capacity test data and related technical issues (2011). Seismic capacity data obtained from past seismic shaking tests were investigated. 2) Test programs based on the investigation of system specification (2011). Design specifications for the air-cooled system were investigated. 3) Large Air Fin Cooler (AFC) one unit model seismic capacity test and quantitative seismic capacity evaluation. AFC one unit model seismic capacity tests were conducted and quantitative seismic capacities were evaluated. (author)

  10. Seismic assessment of air-cooled type emergency electric power supply system

    International Nuclear Information System (INIS)

    2013-01-01

    JNES initiated seismic assessment programs to develop seismic review criterions for the air-cooled system (diesel generator, gas turbine generator), which will be newly installed for enhancing the diversity of emergency electric power supply system. Five principal subjects are involved in the programs: two subjects for fiscal 2011 and three ones for fiscal 2012 and 2013. The summary of outcomes is as follows: 1) Past capacity test data and related technical issues (2011). Seismic capacity data obtained from past seismic shaking tests were investigated. 2) Test programs based on the investigation of system specification (2011). Design specifications for the air-cooled system were investigated. 3) Large Air Fin Cooler (AFC) one unit model seismic capacity test and quantitative seismic capacity evaluation. AFC one unit model seismic capacity tests were conducted and quantitative seismic capacities were evaluated. (author)

  11. Seismic reliability assessment methodology for CANDU concrete containment structures

    International Nuclear Information System (INIS)

    Stephens, M.J.; Nessim, M.A.; Hong, H.P.

    1995-05-01

    A study was undertaken to develop a reliability-based methodology for the assessment of existing CANDU concrete containment structures with respect to seismic loading. The focus of the study was on defining appropriate specified values and partial safety factors for earthquake loading and resistance parameters. Key issues addressed in the work were the identification of an approach to select design earthquake spectra that satisfy consistent safety levels, and the use of structure-specific data in the evaluation of structural resistance. (author). 23 refs., 9 tabs., 15 figs

  12. Assessment of Long-Run Marginal Costing of Transmission and ...

    African Journals Online (AJOL)

    The Long-Run Marginal Costing (LRMC) technique is used as a cost-reflecting pricing method and finds useful application in the recovery of the total investment cost for the use of a transmission or distribution network. This paper reviews recent applications of this technique based on some examples from United Kingdom, ...

  13. Final Report: Seismic Hazard Assessment at the PGDP

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhinmeng [KY Geological Survey, Univ of KY

    2007-06-01

    Selecting a level of seismic hazard at the Paducah Gaseous Diffusion Plant for policy considerations and engineering design is not an easy task because it not only depends on seismic hazard, but also on seismic risk and other related environmental, social, and economic issues. Seismic hazard is the main focus. There is no question that there are seismic hazards at the Paducah Gaseous Diffusion Plant because of its proximity to several known seismic zones, particularly the New Madrid Seismic Zone. The issues in estimating seismic hazard are (1) the methods being used and (2) difficulty in characterizing the uncertainties of seismic sources, earthquake occurrence frequencies, and ground-motion attenuation relationships. This report summarizes how input data were derived, which methodologies were used, and what the hazard estimates at the Paducah Gaseous Diffusion Plant are.

  14. Structure and evolution of the northern Oman margin: gravity and seismic constraints over the Zagros-Makran-Oman collision zone

    Science.gov (United States)

    Ravaut, P.; Bayer, R.; Hassani, R.; Rousset, D.; Yahya'ey, A. Al

    1997-09-01

    The obduction process in Oman during Late Cretaceous time, and continental-to-oceanic subduction along the Zagros-Makran region during the Tertiary are consequences of the Arabian-Eurasian collision, resulting in construction of complex structures composed of the Oman ophiolite belt, the Zagros continental mountain belt and the Makran subduction zone with its associated accretionary wedge. In this paper, we jointly interpret Bouguer anomaly and available petroleum seismic profiles in terms of crustal structures. We show that the gravity anomaly in northern Oman is characterized by a high-amplitude negative-positive couple. The negative anomaly is coincident with Late Cretaceous (Fiqa) and Tertiary (Pabdeh) foreland basins and with the Zagros-Oman mountain belts, whereas the positive anomaly is correlated to the ophiolite massifs. The Bouguer anomaly map indicates the presence of a post-Late Cretaceous sedimentary basin, the Sohar basin, centred north of the Batinah plain. We interpret the negative/positive couple in terms of loading of the elastic Arabian lithosphere. We estimate the different Cretaceous-to-Recent loads, including topography, ophiolite nappes, sedimentary fill and the accretionary prism of the Makran trench. A new method, using Mindlin's elastic plate theory, is proposed to model the 2D deflection of the heterogeneous elastic Arabian plate, taking into account boundary conditions at the ends of the subducted plate. We show that remnant ophiolites are isolated from Tethyan oceanic lithosphere in the Gulf of Oman by a continental basement ridge, a NW prolongation of the Saih-Hatat window. Loading the northward-limited ophiolite blocks explains the deflection of the Fiqa foredeep basin. West of the Musandam Peninsula, the Tertiary Pabdeh foredeep is probably related to the emplacement of a 8-km-thick tectonic prism located on the Musandam Peninsula and in the Strait of Hormuz. Final 2D density models along profiles through the Oman mountain belt and

  15. Geological Constraints on the Evolution of the Angolan Margin Based on Reflection and Refraction Seismic Data (ZaïAngo project)

    Science.gov (United States)

    Moulin, M.; Aslanian, D.; Olivet, J.; Contrucci, I.; Matias, L.; Geli, L.; Klingelhoefer, F.; Nouze, H.; Rabineau, M.; Labails, C.; Rehault, J.; Unternehr, P.

    2005-05-01

    Deep penetration multi-channel reflection and OBS wide-angle seismic data from the Congo-Angola margin were collected in 2000 during the ZaiAngo cruise (Ifremer and Total). These data help constrain the deep structure of the non-volcanic continental margin, the geometry of the pre-salt sediment layers and the geometry of the Aptian salt layer. Dating the deposition of the salt relative to the chronology of the margin formation is an issue of fundamental importance for reconstructing the evolution of the margin and for the understanding of the crustal thinning processes. The data show that the crust thins abruptly, from a 30 - 40km thickness to less than 10km, over a lateral distance of less than 50km. The transitional domain is a 180km wide basin with a thickness lower than 7 km. The pre-salt sediment layering within this basin is parallel to the base of the salt and hardly affected by tectonic deformation. In addition, the presence of a continuous salt cover, from the continental platform down to the presumed oceanic boundary, provides indications on the conditions of salt deposition that constrain the geometry of the margin at that time. These crucial observations imply shallow deposition environments during the rifting and suggest that vertical motions prevailed - compared to horizontal motions - during the formation of the basin.

  16. Geological constraints on the evolution of the Angolan margin based on reflection and refraction seismic data (ZaïAngo project)

    Science.gov (United States)

    Moulin, Maryline; Aslanian, Daniel; Olivet, Jean-Louis; Contrucci, Isabelle; Matias, Luis; Géli, Louis; Klingelhoefer, Frauke; Nouzé, Hervé; Réhault, Jean-Pierre; Unternehr, Patrick

    2005-09-01

    Deep penetration multichannel reflection and Ocean Bottom Seismometer wide-angle seismic data from the Congo-Angola margin were collected in 2000 during the ZaïAngo cruise. These data help constrain the deep structure of the continental margin, the geometry of the pre-salt sediment layers and the geometry of the Aptian salt layer. Dating the deposition of the salt relative to the chronology of the margin formation is an issue of fundamental importance for reconstructing the evolution of the margin and for the understanding of the crustal thinning processes. The data show that the crust thins abruptly, from a 30-40 km thickness to less than 10 km, over a lateral distance of less than 50 km. The transitional domain is a 180-km-wide basin. The pre-salt sediment layering within this basin is parallel to the base of the salt and hardly affected by tectonic deformation. In addition, the presence of a continuous salt cover, from the continental platform down to the presumed oceanic boundary, provides indications on the conditions of salt deposition that constrain the geometry of the margin at that time. These crucial observations imply shallow deposition environments during the rifting and suggest that vertical motions prevailed-compared to horizontal motions-during the formation of the basin.

  17. Potential seismic structural failure modes associated with the Zion Nuclear Plant. Seismic safety margins research program (Phase I). Project VI. Fragilities

    International Nuclear Information System (INIS)

    1979-10-01

    The Zion 1 and 2 Nuclear Power Plant consists of a number of structures. The most important of these from the viewpoint of safety are the containment buildings, the auxiliary building, the turbine building, and the crib house (or intake structure). The evaluation of the potential seismic failure modes and determination of the ultimate seismic capacity of the structures is a complex undertaking which will require a large number of detailed calculations. As the first step in this evaluation, a number of potential modes of structural failure have been determined and are discussed. The report is principally directed towards seismically induced failure of structures. To some extent, modes involving soil foundation failures are discussed in so far as they affect the buildings. However, failure modes involving soil liquefaction, surface faulting, tsunamis, etc., are considered outside the scope of this evaluation

  18. ASSESSMENT OF SEISMIC ANALYSIS METHODOLOGIES FOR DEEPLY EMBEDDED NPP STRUCTURES

    International Nuclear Information System (INIS)

    XU, J.; MILLER, C.; COSTANTINO, C.; HOFMAYER, C.; GRAVES, H. NRC.

    2005-01-01

    Several of the new generation nuclear power plant designs have structural configurations which are proposed to be deeply embedded. Since current seismic analysis methodologies have been applied to shallow embedded structures (e.g., ASCE 4 suggest that simple formulations may be used to model embedment effect when the depth of embedment is less than 30% of its foundation radius), the US Nuclear Regulatory Commission is sponsoring a program at the Brookhaven National Laboratory with the objective of investigating the extent to which procedures acceptable for shallow embedment depths are adequate for larger embedment depths. This paper presents the results of a study comparing the response spectra obtained from two of the more popular analysis methods for structural configurations varying from shallow embedment to complete embedment. A typical safety related structure embedded in a soil profile representative of a typical nuclear power plant site was utilized in the study and the depths of burial (DOB) considered range from 25-100% the height of the structure. Included in the paper are: (1) the description of a simplified analysis and a detailed approach for the SSI analyses of a structure with various DOB, (2) the comparison of the analysis results for the different DOBs between the two methods, and (3) the performance assessment of the analysis methodologies for SSI analyses of deeply embedded structures. The resulting assessment from this study has indicated that simplified methods may be capable of capturing the seismic response for much deeper embedded structures than would be normally allowed by the standard practice

  19. The seismic assessment of fast reactor cores in the UK

    International Nuclear Information System (INIS)

    Duthie, J.C.; Dostal, M.

    1988-01-01

    The design of the UK Commercial Demonstration Fast Reactor (CDFR) has evolved over a number of years. The design has to meet two seismic requirements: (i) the reactor must cause no hazard to the public during or after the Safe Shutdown Earthquake (SSE); (ii) there must be no sudden reduction in safety for an earthquake exceeding the SSE. The core is a complicated component in the whole reactor. It is usually represented in a very simplified manner in the seismic assessment of the whole reactor station. From this calculation, a time history or response spectrum can be generated for the diagrid, which supports the core, and for the above core structure, which supports the main absorber rods. These data may then be used to perform a detailed assessment of the reactor core. A new simplified model of the core response may then be made and used in a further calculation of the whole reactor. The calculation of the core response only, is considered in the remainder of this paper. One important feature of the fast reactor core, compared with other reactors, is that the components are relatively thin and flexible to promote neutron economy and heat transfer. A further important feature is that there are very small gaps between the wrapper tubes. This leads to very strong fluid-coupling effects. These effects are likely to be beneficial, but adequate techniques to calculate them are only just being developed. 9 refs, figs

  20. Corroborating a new probabilistic seismic hazard assessment for greater Tokyo from historical intensity observations

    Science.gov (United States)

    Bozkurt, S.; Stein, R.; Toda, S.

    2006-12-01

    The long recorded history of earthquakes in Japan affords an opportunity to forecast seismic shaking exclusively from past observations of shaking. For this we analyzed 10,000 intensity observations recorded during AD 1600-2000 in a 350 x 350 km area centered on Tokyo in a Geographic Information System. A frequency-intensity curve is found for each 5 x 5 km cell, and from this the probability of exceeding any intensity level can be estimated. The principal benefits of this approach is that it builds the fewest possible assumptions into a probabilistic seismic forecast, it includes site and source effects without imposing this behavior, and we do not need to know the size or location of any earthquake or the location and slip rate of any fault. The cost is that we must abandon any attempt to make a time-dependent forecast, which could be quite different. We believe the method is suitable to many applications of probabilistic seismic hazard assessment, and to other regions. The two key assumptions are that the slope of the observed frequency-intensity relation at every site is the same, and that the 400-year record is long enough to encompass the full range of seismic behavior. Tests we conduct suggest that both assumptions are sound. The resulting 30-year probability of IJMA>=6 shaking (roughly equivalent to PGA>=0.9 g or MMI=IX-X) is 30-40% in Tokyo, Kawasaki, and Yokohama, and 10-15% in Chiba and Tsukuba, the range reflecting spatial variability and curve-fitting alternatives. The strongest shaking is forecast along the margins of Tokyo Bay, within the river sediments extending northwest from Tokyo, and at coastal sites near the plate boundary faults. We also produce long- term exceedance maps of peak ground acceleration for building code regulations, and short-term hazard maps associated with hypothetical catastrophe bonds. Our results for greater Tokyo resemble our independent Poisson probability developed from conventional seismic hazard analysis, as well as

  1. Seismic component fragility data base for IPEEE

    International Nuclear Information System (INIS)

    Bandyopadhyay, K.; Hofmayer, C.

    1990-01-01

    Seismic probabilistic risk assessment or a seismic margin study will require a reliable data base of seismic fragility of various equipment classes. Brookhaven National Laboratory (BNL) has selected a group of equipment and generically evaluated the seismic fragility of each equipment class by use of existing test data. This paper briefly discusses the evaluation methodology and the fragility results. The fragility analysis results when used in the Individual Plant Examination for External Events (IPEEE) Program for nuclear power plants are expected to provide insights into seismic vulnerabilities of equipment for earthquakes beyond the design basis. 3 refs., 1 fig., 1 tab

  2. Crustal structure variations along the NW-African continental margin: a comparison of new and existing models from wide angle and reflection seismic data

    Science.gov (United States)

    Biari, Y.; Klingelhoefer, F.; Sahabi, M.; Aslanian, D.; Philippe, S.; Louden, K. E.; Berglar, K.; Moulin, M.; Mehdi, K.; Graindorge, D.; Evain, M.; Benabellouahed, M.; Reichert, C. J.

    2014-12-01

    Deep seismic data represent a key to understand the geometry and mechanism of continental rifting. The passive continental margin of NW-Africa is one of the oldest on earth, formed during the Upper Triassic-Lower Liassic rifting of the central Atlantic Ocean over 200 Ma. We present new and existing wide-angle and reflection seismic data from three study regions along the margin located in the North Moroccan salt basin, on the central continental margin offshore Safi and in the south, offshore Dakhla. In each of the study areas several combined wide-angle and reflection seismic profiles perpendicular and parallel to the margin have been acquired and forward modelled using comparable methods. The thickness of unthinned continental crust decreases from 36 km in the North to about 27 km in the South. In the North Moroccan Basin continental crust thins from originally 36 km to about 8 km in a 150 km wide zone. The basin itself is underlain by highly thinned continental crust. Offshore safi thinning of the continental crust is confined to a 130 km wide zone with no neighboring sedimentary basin underlain by continental crust. In both areas the zone of crustal thinning is characterised by the presence of large blocks and abundant salt diapirs. In the south crustal thinning is more rapid in a zone of 90 km and asymmetric with the upper crust thinning more closely to the continent than the lower crust, probably due to depth-dependent stretching and the presence of the precambrian Reguibat Ridge on land. Oceanic crust is characterised by a thickness of 7-8 km along the complete margin. Relatively high velocities of up to 7.5 km/s have been imaged between magnetic anomalies S1 and M25, and are probably related to changes in the spreading velocities at the time of the Kimmeridgian/Tithonian plate reorganisation. Volcanic activity seems to be confined to the region next to the Canary Islands, and is thus not related to the initial opening of the oceanic, which was related to no

  3. Assessment of Submarine Slope Stability on the Continental Margin off SW Taiwan

    Science.gov (United States)

    Hsu, Huai-Houh; Dong, Jia-Jyun; Cheng, Win-Bin; Su, Chih-Chieh

    2017-04-01

    The abundant gas hydrate reservoirs are distributed in the southwest (SW) off Taiwan. To explore this new energy, geological methods were systematically used and mainly emphasized on the storage potential evaluation. On the other hand, the correlation between gas hydrate dissociation and submarine slope stability is also an important issue. In this study, three submarine profiles on the active and passive continental margin were selected and assessed their slope stabilities by considering two influence factors (seismic forces and number of sedimentary layers). The gravity corers obtained from these three sites (Xiaoliuqiu, Yuan-An Ridge, and Pointer Ridge) to conduct soil laboratory tests. The physical property tests and isotropically consolidated undrained (CIU) triaxial tests were carried out to establish reference properties and shear strength parameters. Before the stability analysis is performed, it is also necessary to construct the seabed profile. For each submarine profile, data from P-waves and from S-waves generated by P-S conversion on reflection from airgun shots recorded along one line of ocean bottom seismometers were used to construct 2-D velocity sections. The seabed strata could be simplified to be only one sedimentary layer or to be multilayer in accordance with the velocity structure profile. Results show the safety factors (FS) of stability analysis are obviously different in considering the number of sedimentary layers, especially for a very thin layer of sediments on a steep slope. The simplified strata condition which treated all seabed strata as only one sedimentary layer might result in the FS lower than 1 and the slope was in an unstable state. On the contrary, the FS could be higher than 10 in a multilayer condition.

  4. Scientific Ocean Drilling to Assess Submarine Geohazards along European Margins

    Science.gov (United States)

    Ask, M. V.; Camerlenghi, A.; Kopf, A.; Morgan, J. K.; Ocean DrillingSeismic Hazard, P. E.

    2008-12-01

    Submarine geohazards are some of the most devastating natural events in terms of lives lost and economic impact. Earthquakes pose a big threat to society and infrastructure, but the understanding of their episodic generation is incomplete. Tsunamis are known for their potential of striking coastlines world-wide. Other geohazards originating below the sea surface are equally dangerous for undersea structures and the coastal population: submarine landslides and volcanic islands collapse with little warning and devastating consequences. The European scientific community has a strong focus on geohazards along European and nearby continental margins, especially given their high population densities, and long historic and prehistoric record of hazardous events. For example, the Mediterranean is surrounded by very densely-populated coastline and is the World's leading holiday destination, receiving up 30% of global tourism. In addition, its seafloor is criss-crossed by hydrocarbon pipelines and telecommunication cables. However, the governing processes and recurrence intervals of geohazards are still poorly understood. Examples include, but are not limited to, earthquakes and volcanic eruptions along the active tectonic margins of the Mediterranean and Sea of Marmara, landslides on both active and passive margins, and tsunamites and seismites in the sedimentary record that suggest a long history of similar events. The development of geophysical networks, drilling, sampling and long-term monitoring are crucial to the understanding of earthquake, landslide, and tsunami processes, and to mitigate the associated risks in densely populated and industrialized regions such as Europe. Scientific drilling, particularly in the submarine setting, offers a unique tool to obtain drill core samples, borehole measurements and long-term observations. Hence, it is a critical technology to investigate past, present, and possible future influences of hazardous processes in this area. The

  5. Modification of prostate implants based on postimplant treatment margin assessment.

    Science.gov (United States)

    Mueller, Amy; Wallner, Kent; Merrick, Gregory; Courveau, Jacques; Sutlief, Steven; Butler, Wayne; Gong, Lixin; Cho, Paul

    2002-12-01

    To quantify the extent of additional source placement needed to perfect an implant after execution by standard techniques, assuming that uniform 5 mm treatment margins (TMs) is the criteria for perfection. Ten consecutive, unselected patients treated with 1-125 brachytherapy were studied. Source placement is planned just inside or outside of the prostatic margin, to achieve a minimum 5 mm TM and a central dose of 150%-200% of the prescription dose. The preimplant prostate volumes ranged from 24 to 85 cc (median: 35 cc). The number of sources implanted ranged from 48 to 102 (median: 63). Axial CT images were acquired within 2 h postoperatively for postimplant dosimetry. After completion of standard dosimetric calculations, the TMs were measured and tabulated at 45 degrees intervals around the prostate periphery at 0.0, 1.0, 2.0, and 3.0 cm planes. Sources were then added to the periphery to bring the TMs to a minimum of 5 mm at each measured TM, resulting in a modified implant. All margin modifications were done manually, without the aid of automated software. Patients' original (unmodified) D90s ranged from 111% to 154%, with a median of 116%. The original V100s ranged from 94% to 99%, with a median of 96%. No patient required placement of additional sources to meet a minimum D90 of 90% or a minimum V100 of 80%. In contrast, patients required from 7 to 17 additional sources (median: 11) to achieve minimum 5 mm TMs around the entire prostatic periphery. Additional sources equaled from 12% to 24% of the initial number of sources placed (median: 17%). By adding sufficient peripheral sources to bring the TMs to a minimum 5 mm, patients' average V100 increased from 96% to 100%, and the average D90 increased from 124% to 160% of prescription dose. In the course of achieving a minimum 5 mm TM, the average treatment margin for all patients combined increased from 5.5 to 9.9 mm. The number of sources needed to bring the TMs to a minimum 5 mm was loosely correlated with the

  6. Modification of prostate implants based on postimplant treatment margin assessment

    International Nuclear Information System (INIS)

    Mueller, Amy; Wallner, Kent; Merrick, Gregory; Couriveau, Jacques; Sutlief, Steven; Butler, Wayne; Gong, Lixin; Cho, Paul

    2002-01-01

    Purpose: To quantify the extent of additional source placement needed to perfect an implant after execution by standard techniques, assuming that uniform 5 mm treatment margins (TMs) is the criteria for perfection. Materials and Methods: Ten consecutive, unselected patients treated with I-125 brachytherapy were studied. Source placement is planned just inside or outside of the prostatic margin, to achieve a minimum 5 mm TM and a central dose of 150%-200% of the prescription dose. The preimplant prostate volumes ranged from 24 to 85 cc (median: 35 cc). The number of sources implanted ranged from 48 to 102 (median: 63). Axial CT images were acquired within 2 h postoperatively for postimplant dosimetry. After completion of standard dosimetric calculations, the TMs were measured and tabulated at 45 deg. intervals around the prostate periphery at 0.0, 1.0, 2.0, and 3.0 cm planes. Sources were then added to the periphery to bring the TMs to a minimum of 5 mm at each measured TM, resulting in a modified implant. All margin modifications were done manually, without the aid of automated software. Results: Patients' original (unmodified) D90s ranged from 111% to 154%, with a median of 116%. The original V100s ranged from 94% to 99%, with a median of 96%. No patient required placement of additional sources to meet a minimum D90 of 90% or a minimum V100 of 80%. In contrast, patients required from 7 to 17 additional sources (median: 11) to achieve minimum 5 mm TMs around the entire prostatic periphery. Additional sources equaled from 12% to 24% of the initial number of sources placed (median: 17%). By adding sufficient peripheral sources to bring the TMs to a minimum 5 mm, patients' average V100 increased from 96% to 100%, and the average D90 increased from 124% to 160% of prescription dose. In the course of achieving a minimum 5 mm TM, the average treatment margin for all patients combined increased from 5.5 to 9.9 mm. The number of sources needed to bring the TMs to a minimum

  7. How does continental lithosphere break-apart? A 3D seismic view on the transition from magma-poor rifted margin to magmatic oceanic lithosphere

    Science.gov (United States)

    Emmanuel, M.; Lescanne, M.; Picazo, S.; Tomasi, S.

    2017-12-01

    In the last decade, high-quality seismic data and drilling results drastically challenged our ideas about how continents break apart. New models address their observed variability and are presently redefining basics of rifting as well as exploration potential along deepwater rifted margins. Seafloor spreading is even more constrained by decades of scientific exploration along Mid Oceanic Ridges. By contrast, the transition between rifting and drifting remains a debated subject. This lithospheric breakup "event" is geologically recorded along Ocean-Continent Transitions (OCT) at the most distal part of margins before indubitable oceanic crust. Often lying along ultra-deepwater margin domains and buried beneath a thick sedimentary pile, high-quality images of these domains are rare but mandatory to get strong insights on the processes responsible for lithospheric break up and what are the consequences for the overlying basins. We intend to answer these questions by studying a world-class 3D seismic survey in a segment of a rifted margin exposed in the Atlantic. Through these data, we can show in details the OCT architecture between a magma-poor hyper-extended margin (with exhumed mantle) and a classical layered oceanic crust. It is characterized by 1- the development of out-of-sequence detachment systems with a landward-dipping geometry and 2- the increasing magmatic additions oceanwards (intrusives and extrusives). Geometry of these faults suggests that they may be decoupled at a mantle brittle-ductile interface what may be an indicator on thermicity. Furthermore, magmatism increases as deformation migrates to the future first indubitable oceanic crust what controls a progressive magmatic crustal thickening below, above and across a tapering rest of margin. As the magmatic budget increases oceanwards, full-rate divergence is less and less accommodated by faulting. Magmatic-sedimentary architectures of OCT is therefore changing from supra-detachment to magmatic

  8. ACED devices and SECAF supports for the control of structure, pipe network and equipment behaviour at seismic movements in order to enhance the safety margin

    International Nuclear Information System (INIS)

    Serban, Viorel; Prisecaru, I.; Cretu, D.; Moldoveanu, T.

    2002-01-01

    In order to enhance the safety margin of structure, pipe networks and equipment associated to the existing NPPs, the classic consolidation solutions are very expensive and many times, impossible to be implemented. Structures, pipe networks, systems and equipment have geometries imposed by the basic construction requirements, operating and safety requirements and their modifications is not always possible. In order to enhance the strength capacity of (new or old) structures, systems and equipment mechanical devices with controlled elasticity and damping (ACED) have been designed, constructed and experimented. These devices are capable to support very large static loads over which dynamic loads (shock, vibration and seismic movements) overlap (which are damped). To increase the strength capacity of (new or existing) pipe networks and equipment connecting with pipes, SECAF supports that allow displacements from thermal expansions with low reaction force have been designed, constructed and experimented. SECAF supports are capable elastically to take permanent loads over which shocks, vibrations and seismic movements (which are damp) overlap. ACED devices and SECAF supports can be used to rehabilitate the existing NPPs with law financial costs and an increase of their strength capacity up to 100% under seismic movements, shocks and vibrations. ACED devices and SECAF supports do not require maintenance, are not affected by presence of a radiation field and their estimated service-life is similar to the NPPs

  9. Recent achievements of the neo-deterministic seismic hazard assessment in the CEI region

    International Nuclear Information System (INIS)

    Panza, G.F.; Vaccari, F.; Kouteva, M.

    2008-03-01

    A review of the recent achievements of the innovative neo-deterministic approach for seismic hazard assessment through realistic earthquake scenarios has been performed. The procedure provides strong ground motion parameters for the purpose of earthquake engineering, based on the deterministic seismic wave propagation modelling at different scales - regional, national and metropolitan. The main advantage of this neo-deterministic procedure is the simultaneous treatment of the contribution of the earthquake source and seismic wave propagation media to the strong motion at the target site/region, as required by basic physical principles. The neo-deterministic seismic microzonation procedure has been successfully applied to numerous metropolitan areas all over the world in the framework of several international projects. In this study some examples focused on CEI region concerning both regional seismic hazard assessment and seismic microzonation of the selected metropolitan areas are shown. (author)

  10. Seismic Hazard Assessment at Esfaraen‒Bojnurd Railway, North‒East of Iran

    Science.gov (United States)

    Haerifard, S.; Jarahi, H.; Pourkermani, M.; Almasian, M.

    2018-01-01

    The objective of this study is to evaluate the seismic hazard at the Esfarayen-Bojnurd railway using the probabilistic seismic hazard assessment (PSHA) method. This method was carried out based on a recent data set to take into account the historic seismicity and updated instrumental seismicity. A homogenous earthquake catalogue was compiled and a proposed seismic sources model was presented. Attenuation equations that recently recommended by experts and developed based upon earthquake data obtained from tectonic environments similar to those in and around the studied area were weighted and used for assessment of seismic hazard in the frame of logic tree approach. Considering a grid of 1.2 × 1.2 km covering the study area, ground acceleration for every node was calculated. Hazard maps at bedrock conditions were produced for peak ground acceleration, in addition to return periods of 74, 475 and 2475 years.

  11. Performance-based methodology for assessing seismic vulnerability and capacity of buildings

    Science.gov (United States)

    Shibin, Lin; Lili, Xie; Maosheng, Gong; Ming, Li

    2010-06-01

    This paper presents a performance-based methodology for the assessment of seismic vulnerability and capacity of buildings. The vulnerability assessment methodology is based on the HAZUS methodology and the improved capacitydemand-diagram method. The spectral displacement ( S d ) of performance points on a capacity curve is used to estimate the damage level of a building. The relationship between S d and peak ground acceleration (PGA) is established, and then a new vulnerability function is expressed in terms of PGA. Furthermore, the expected value of the seismic capacity index (SCev) is provided to estimate the seismic capacity of buildings based on the probability distribution of damage levels and the corresponding seismic capacity index. The results indicate that the proposed vulnerability methodology is able to assess seismic damage of a large number of building stock directly and quickly following an earthquake. The SCev provides an effective index to measure the seismic capacity of buildings and illustrate the relationship between the seismic capacity of buildings and seismic action. The estimated result is compared with damage surveys of the cities of Dujiangyan and Jiangyou in the M8.0 Wenchuan earthquake, revealing that the methodology is acceptable for seismic risk assessment and decision making. The primary reasons for discrepancies between the estimated results and the damage surveys are discussed.

  12. Seismic qualification of equipment by means of probabilistic risk assessment

    International Nuclear Information System (INIS)

    Azarm, M.A.; Farahzad, P.; Boccio, J.L.

    1982-01-01

    Upon the sponsorship of the Equipment Qualification Branch (EQB) of NRC, Brookhaven National Laboratory (BNL) has utilized a risk-based approach for identifying, in a generic fashion, seismically risk-sensitive equipment. It is anticipated that the conclusions drawn therefrom and the methodology employed will, in part, reconcile some of the concerns dealing with the seismic qualification of equipment in operating plants. The approach taken augments an existing sensitivity analysis, based upon the WASH-1400 Reactor Safety Study (RSS), by accounting for seismicity and component fragility with the Kennedy model and by essentially including the requisite seismic data presented in the Zion Probabilistic Safety Study (ZPSS). Parametrically adjusting the seismic-related variables and ascertaining their effects on overall plant risk, core-melt probability, accident sequence probability, etc., allows one to identify those seismically risk-sensitive systems and equipment. This paper describes the approach taken and highlights the results obtained thus far for a hypothetical pressurized water reactor

  13. Assessing Students in the Margin: Challenges, Strategies, and Techniques

    Science.gov (United States)

    Russell, Michael; Kavanaugh, Maureen

    2011-01-01

    The importance of student assessment, particularly for summative purposes, has increased greatly over the past thirty years. At the same time, emphasis on including all students in assessment programs has also increased. Assessment programs, whether they are large-scale, district-based, or teacher developed, have traditionally attempted to assess…

  14. Operating experience and aging-seismic assessment of electric motors

    International Nuclear Information System (INIS)

    Subudhi, M.; Burns, E.L.; Taylor, J.H.

    1985-06-01

    Objectives of this program are to identify concerns related to the aging and service wear of equipment operating in nuclear power plants, to assess their possible impact on plant safety, to identify effective inspection surveillance and monitoring methods and to recommend suitable maintenance practices for mitigating aging related concerns and diminish the rate of degradation due to aging and service wear. Motor design and materials of construction are reviewed to identify age-sensitive components. Operational and accidental stressors are determined, and their effect on promoting aging degradation is assessed. Failure modes, mechanisms, and causes have been reviewed from operating experiences and existing data banks. The study has also included consideration for the seismic correlation of age-degraded motor components. The aforementioned reviews and assessments were assimilated to characterize the dielectric, rotational, and mechanical hazards on motor performance and operational readiness. The functional indicators which can be monitored to assess motor component deterioration due to aging or other accidental stressors are identified. Conforming with the NPAR strategy as outlined in the program plan, the study also includes a preliminary discussion of current standards and guides, maintenance programs, and research activities pertaining to nuclear power plant safety-related electric motors

  15. Seismic Performance Assessment and Strengthening of Gazimagusa Namik Kemal Lisesi

    OpenAIRE

    Yardımcı, Temuçin

    2009-01-01

    ABSTRACT: Many destructive earthquakes occurred in Cyprus. However, the potential seismic risk of the buildings in Cyprus is not known well since vulnerability is unknown. Especially in the Northern part of the Island building inventory has variation regarding seismic performance. On the other hand, in Northern Cyprus there are more than 150 school buildings with different ages. Most of these buildings have been constructed before the use of modern seismic codes. In other words, only gravity...

  16. Seismic Isolation of Liquefied Natural Gas Tanks: a Compartive Assessment

    OpenAIRE

    Marti Rodriguez, Joaquin; Crespo Álvarez, María José; Martinez Cutillas, Francisco J.

    2010-01-01

    In severe seismic environments, tanks for storage of liquefied natural gas may benefit from seismic isolation. As the design accelerations increase, the inner tank undergoes progressively greater demands and may suffer from corner uplift, elephant’s foot buckling, gross sliding, shell thickness requirements beyond what can be reliably welded and, eventually, global uplift. Some of these problems cause extra costs while others make the construction impossible. The seismic environments at which...

  17. Energy system analyses of the marginal energy technology in life cycle assessments

    DEFF Research Database (Denmark)

    Mathiesen, B.V.; Münster, Marie; Fruergaard, Thilde

    2007-01-01

    in historical and potential future energy systems. Subsequently, key LCA studies of products and different waste flows are analysed in relation to the recom- mendations in consequential LCA. Finally, a case of increased waste used for incineration is examined using an energy system analysis model......In life cycle assessments consequential LCA is used as the “state-of-the-art” methodology, which focuses on the consequences of decisions made in terms of system boundaries, allocation and selection of data, simple and dynamic marginal technology, etc.(Ekvall & Weidema 2004). In many LCA studies...... marginal technology? How is the marginal technology identified and used today? What is the consequence of not using energy system analy- sis for identifying the marginal energy technologies? The use of the methodology is examined from three angles. First, the marginal electricity technology is identified...

  18. Digital tomosynthesis rendering of joint margins for arthritis assessment

    Science.gov (United States)

    Duryea, Jeffrey W.; Neumann, Gesa; Yoshioka, Hiroshi; Dobbins, James T., III

    2004-05-01

    PURPOSE: Rheumatoid arthritis (RA) of the hand is a significant healthcare problem. Techniques to accurately quantity the structural changes from RA are crucial for the development and prescription of therapies. Analysis of radiographic joint space width (JSW) is widely used and has demonstrated promise. However, radiography presents a 2D view of the joint. In this study we performed tomosynthesis reconstructions of proximal interphalangeal (PIP), and metacarpophalangeal (MCP) joints to measure the 3D joint structure. METHODS: We performed a reader study using simulated radiographs of 12 MCP and 12 PIP joints from skeletal specimens imaged with micro-CT. The tomosynthesis technique provided images of reconstructed planes with 0.75 mm spacing, which were presented to 2 readers with a computer tool. The readers were instructed to delineate the joint surfaces on tomosynthetic slices where they could visualize the margins. We performed a quantitative analysis of 5 slices surrounding the central portion of each joint. Reader-determined JSW was compared to a gold standard. As a figure of merit we calculated the average root-mean square deviation (RMSD). RESULTS: RMSD was 0.22 mm for both joints. For the individual joints, RMSD was 0.18 mm (MCP), and 0.26 mm (PIP). The reduced performance for the smaller PIP joints suggests that a slice spacing less than 0.75 mm may be more appropriate. CONCLUSIONS: We have demonstrated the capability of limited 3D rendering of joint surfaces using digital tomosynthesis. This technique promises to provide an improved method to visualize the structural changes of RA.

  19. Overview of seismic probabilistic risk assessment for structural analysis in nuclear facilities

    International Nuclear Information System (INIS)

    Reed, J.W.

    1989-01-01

    Probabilistic Risk Assessment (PRA) for seismic events is currently being performed for nuclear and DOE facilities. The background on seismic PRA is presented along with a basic description of the method. The seismic PRA technique is applicable to other critical facilities besides nuclear plants. The different approaches for obtained structure fragility curves are discussed and their applications to structures and equipment, in general, are addressed. It is concluded that seismic PRA is a useful technique for conducting probability analysis for a wide range of classes of structures and equipment

  20. Assessment of wind turbine seismic risk : existing literature and simple study of tower moment demand.

    Energy Technology Data Exchange (ETDEWEB)

    Prowell, Ian (University of California, San Diego, CA); Veers, Paul S.

    2009-03-01

    Various sources of risk exist for all civil structures, one of which is seismic risk. As structures change in scale, the magnitude of seismic risk changes relative to risk from other sources. This paper presents an introduction to seismic hazard as applied to wind turbine structures. The existing design methods and research regarding seismic risk for wind turbines is then summarized. Finally a preliminary assessment is made based on current guidelines to understand how tower moment demand scales as rated power increases. Potential areas of uncertainty in the application of the current guidelines are summarized.

  1. Seismic assessment and performance of nonstructural components affected by structural modeling

    Energy Technology Data Exchange (ETDEWEB)

    Hur, Jieun; Althoff, Eric; Sezen, Halil; Denning, Richard; Aldemir, Tunc [Ohio State University, Columbus (United States)

    2017-03-15

    Seismic probabilistic risk assessment (SPRA) requires a large number of simulations to evaluate the seismic vulnerability of structural and nonstructural components in nuclear power plants. The effect of structural modeling and analysis assumptions on dynamic analysis of 3D and simplified 2D stick models of auxiliary buildings and the attached nonstructural components is investigated. Dynamic characteristics and seismic performance of building models are also evaluated, as well as the computational accuracy of the models. The presented results provide a better understanding of the dynamic behavior and seismic performance of auxiliary buildings. The results also help to quantify the impact of uncertainties associated with modeling and analysis of simplified numerical models of structural and nonstructural components subjected to seismic shaking on the predicted seismic failure probabilities of these systems.

  2. Seismic and wind vulnerability assessment for the GAR-13 global risk assessment

    OpenAIRE

    Yamín Lacouture, Luis Eduardo; Hurtado Chaparro, Alvaro Ivan; Barbat Barbat, Horia Alejandro; Cardona Arboleda, Omar Dario

    2014-01-01

    A general methodology to evaluate vulnerability functions suitable for a probabilistic global risk assessment is proposed. The methodology is partially based in the methodological approach of the Multi-hazard Loss Estimation Methodology (Hazus) developed by the Federal Emergency Management Agency (FEMA). The vulnerability assessment process considers the resolution, information and limitations established for both the hazard and exposure models adopted. Seismic and wind vulnerability function...

  3. Seismic source zone characterization for the seismic hazard assessment project PEGASOS by the Expert Group 2 (EG1b)

    International Nuclear Information System (INIS)

    Burkhard, M.; Gruenthal, G.

    2009-01-01

    A comprehensive study of the seismic hazard related to the four NNP sites in NW Switzerland was performed within the project PEGASOS. To account for the epistemic uncertainties involved in the process of the characterization of seismic source zones in the frame of probabilistic seismic hazard assessments, four different expert teams have developed and defended their models in the frame of an intensive elicitation process. Here, the results of one out of four expert groups are presented. The model of this team is based first of all on considerations regarding the large scale tectonics in the context of the Alpine collision, and neotectonic constraints for defining seismic source zones. This leads to a large scale subdivision based on the structural 'architectural' considerations with little input from the present seismicity. Each of the eight large zones was characterized by the style of present-day faulting, fault orientation, and hypo central depth distribution. A further subdivision of the larger zones is performed based on information provided by the seismicity patterns. 58 small source zones have been defined in this way, each of them characterized by the available tectonic constrains, as well as the pros and cons of different existing geologic views connected to them. Of special concern in this respect were the discussion regarding thin skinned vs. thick skinned tectonics, the tectonic origin of the 1356 Basel earthquake, the role of the Permo-Carboniferous graben structures, and finally the seismogenic orientation of faults with respect to the recent crustal stress field. The uncertainties connected to the delimitations of the small source zones have been handled in form of their regrouping, formalized by the logic tree technique. The maximum magnitudes were estimated as discretized probability distribution functions. After de-clustering the used ECOS earthquake catalogue and an analysis of data completeness as a function of time the parameters of the

  4. Tectonic erosion and consequent collapse of the Pacific margin of Costa Rica: Combined implications from ODP leg 170, seismic offshore data, and regional geology of the Nicoya Peninsula

    Science.gov (United States)

    Vannucchi, P.; Scholl, D. W.; Meschede, M.; McDougall-Reid, K.

    2001-01-01

    The convergent margin off the Pacific coast of the Nicoya Peninsula of Costa Rica exhibits evidence for subduction erosion caused by the underthrusting Cocos plate. Critical evidence for efficacy of this process was recovered at the Ocean Drilling Program (ODP) drilling Site 1042 (Leg 170), positioned ???7 km landward of the Middle America trench axis off the Nicoya Peninsula. The primary drilling objective at this site was to identify the age and origin of a regionally extensive and prominent seismic discontinuity, the so-called base-of-slope sediment (BOSS) horizon or surface. The BOSS horizon, which can be traced landward from near the trench to the Nicoya coastal area and parallel to it for hundreds of kilometers, separates a low-velocity (??? 2.0-2.5 km s-1) sequence of slope sediment, from an underlying sequence of much higher-velocity (> 4-4.5 km s-1) rock. Site 1042 reached the acoustically defined BOSS horizon at a below sea level depth of ??? 3900 m and yielded a carbonate-cemented calcarenitic breccia of early-middle Miocene age. Sedimentological, geochemical, paleontological, and cement paragenesis data document that the breccia accumulated in a shallow water depositional environment. On the basis of coastal exposures, the BOSS horizon, as a margin-wide geologic interface, can be temporally and lithostratigraphically correlated to a regional angular unconformity. This unconformity, known as the Mal Pais unconformity, separates Neogene and younger shelf-to-littoral beds from the underlying mafic units of the Mesozoic Nicoya Complex and Cretaceous and early Tertiary sedimentary sequences. At Site 1042 it is inferred that tectonism caused the vertical subsidence of the early Neogene breccia from a shallow to a deep water setting. The Mal Pais unconformity of the BOSS horizon thus connects the rock fabric of the outermost part of margin to that of coastal Nicoya and implies that in the early Neogene the Nicoya shelf extended seaward to near the present

  5. Role of seismic PRA in seismic safety decisions of nuclear power plants

    International Nuclear Information System (INIS)

    Ravindra, M.K.; Kennedy, R.P.; Sues, R.H.

    1985-01-01

    This paper highlights the important roles that seismic probabilistic risk assessments (PRAs) can play in the seismic safety decisions of nuclear power plants. If a seismic PRA has been performed for a plant, its results can be utilized to evaluate the seismic capability beyond the safe shutdown event (SSE). Seismic fragilities of key structures and equipment, fragilities of dominant plant damage states and the frequencies of occurrence of these plant damage states are reviewed to establish the seismic safety of the plant beyond the SSE level. Guidelines for seismic margin reviews and upgrading may be developed by first identifying the generic classes of structures and equipment that have been shown to be dominant risk contributors in the completed seismic PRAs, studying the underlying causes for their contribution and examining why certain other items (e.g., piping) have not proved to be high-risk-contributors

  6. Miocene uplift of the NE Greenland margin linked to plate tectonics: Seismic evidence from the Greenland Fracture Zone, NE Atlantic

    DEFF Research Database (Denmark)

    Døssing Andreasen, Arne; Japsen, Peter; Watts, Anthony B.

    2016-01-01

    Tectonic models predict that, following breakup, rift margins undergo only decaying thermal subsidence during their post-rift evolution. However, post-breakup stratigraphy beneath the NE Atlantic shelves shows evidence of regional-scale unconformities, commonly cited as outer margin responses to ...... by plate tectonic forces, induced perhaps by a change in the Iceland plume (a hot pulse) and/or by changes in intra-plate stresses related to global tectonics.......Tectonic models predict that, following breakup, rift margins undergo only decaying thermal subsidence during their post-rift evolution. However, post-breakup stratigraphy beneath the NE Atlantic shelves shows evidence of regional-scale unconformities, commonly cited as outer margin responses...... backstripping. We explain the thermo-mechanical coupling and the deposition of contourites by the formation of a continuous plate boundary along the Mohns and Knipovich ridges, leading to an accelerated widening of the Fram Strait. We demonstrate that the IMU event is linked to onset of uplift and massive shelf...

  7. Methodology and results of the seismic probabilistic safety assessment of Krsko nuclear power plant

    International Nuclear Information System (INIS)

    Vermaut, M.K.; Monette, P.; Campbell, R.D.

    1995-01-01

    A seismic IPEEE (Individual Plant Examination for External Events) was performed for the Krsko plant. The methodology adopted is the seismic PSA (Probabilistic Safety Assessment). The Krsko NPP is located on a medium to high seismicity site. The PSA study described here includes all the steps in the PSA sequence, i.e. reassessment of the site hazard, calculation of plant structures response including soil-structure interaction, seismic plant walkdowns, probabilistic seismic fragility analysis of plant structures and components, and quantification of seismic core damage frequency (CDF). Also relay chatter analysis and soil stability studies were performed. The seismic PSA described here is limited to the analysis of CDF (level I PSA). The subsequent determination and quantification of plant damage states, containment behaviour and radioactive releases to the outside (level 2 PSA) have been performed for the Krsko NPP but are not further described in this paper. The results of the seismic PSA study indicate that, with some upgrades suggested by the PSA team, the seismic induced CDF is comparable to that of most US and Western Europe NPPs. (author)

  8. Seismic Hazard Assessment in Site Evaluation for Nuclear Installations: Ground Motion Prediction Equations and Site Response

    International Nuclear Information System (INIS)

    2016-07-01

    The objective of this publication is to provide the state-of-the-art practice and detailed technical elements related to ground motion evaluation by ground motion prediction equations (GMPEs) and site response in the context of seismic hazard assessments as recommended in IAEA Safety Standards Series No. SSG-9, Seismic Hazards in Site Evaluation for Nuclear Installations. The publication includes the basics of GMPEs, ground motion simulation, selection and adjustment of GMPEs, site characterization, and modelling of site response in order to improve seismic hazard assessment. The text aims at delineating the most important aspects of these topics (including current practices, criticalities and open problems) within a coherent framework. In particular, attention has been devoted to filling conceptual gaps. It is written as a reference text for trained users who are responsible for planning preparatory seismic hazard analyses for siting of all nuclear installations and/or providing constraints for anti-seismic design and retrofitting of existing structures

  9. The seismic assessment of radially keyed graphite moderator cores

    International Nuclear Information System (INIS)

    Steer, A.G.; Payne, J.F.B.

    1996-01-01

    The modelling of AGR and Magnox cores has to deal with the very large number of components that make up the core, and the non-linear response due to the clearances in the keying system. This paper examines the conditions under which it is permissible to linearise the response. By comparing the results of discrete and continuum models of the core, the paper also shows that the number of components in the core is sufficiently large that the core can be approximated satisfactorily by an anisotropic solid material. The material has unusual properties, but these can be handled within the standard framework for the description of the elastic properties of an anisotropic solid. This description of the core by an equivalent solid material can readily be incorporated into finite element models of the reactor internal structure. Such models have been set up for both AGR and Magnox reactors. The models are being used to assess the seismic response of these reactors. (author). 5 refs, 6 figs

  10. Seismic hazard assessment based on the Unified Scaling Law for Earthquakes: the Greater Caucasus

    Science.gov (United States)

    Nekrasova, A.; Kossobokov, V. G.

    2015-12-01

    Losses from natural disasters continue to increase mainly due to poor understanding by majority of scientific community, decision makers and public, the three components of Risk, i.e., Hazard, Exposure, and Vulnerability. Contemporary Science is responsible for not coping with challenging changes of Exposures and their Vulnerability inflicted by growing population, its concentration, etc., which result in a steady increase of Losses from Natural Hazards. Scientists owe to Society for lack of knowledge, education, and communication. In fact, Contemporary Science can do a better job in disclosing Natural Hazards, assessing Risks, and delivering such knowledge in advance catastrophic events. We continue applying the general concept of seismic risk analysis in a number of seismic regions worldwide by constructing regional seismic hazard maps based on the Unified Scaling Law for Earthquakes (USLE), i.e. log N(M,L) = A - B•(M-6) + C•log L, where N(M,L) is the expected annual number of earthquakes of a certain magnitude M within an seismically prone area of linear dimension L. The parameters A, B, and C of USLE are used to estimate, first, the expected maximum magnitude in a time interval at a seismically prone cell of a uniform grid that cover the region of interest, and then the corresponding expected ground shaking parameters including macro-seismic intensity. After a rigorous testing against the available seismic evidences in the past (e.g., the historically reported macro-seismic intensity), such a seismic hazard map is used to generate maps of specific earthquake risks (e.g., those based on the density of exposed population). The methodology of seismic hazard and risks assessment based on USLE is illustrated by application to the seismic region of Greater Caucasus.

  11. Influence of obliquely subducting slab on Pacific-North America shear motion inferred from seismic anisotropy along the Queen Charlotte margin

    Science.gov (United States)

    Cao, L.; Kao, H.; Wang, K.; Wang, Z.

    2016-12-01

    Haida Gwaii is located along the transpressive Queen Charlotte margin between the Pacific (PA) and North America (NA) plates. The highly oblique relative plate motion is partitioned, with the strike-slip component accommodated by the Queen Charlotte Fault (QCF) and the convergent component by a thrust fault offshore. To understand how the presence of a obliquely subducting slab influences shear deformation of the plate boundary, we investigate mantle anisotropy by analyzing shear-wave splitting of teleseismic SKS phases recorded at 17 seismic stations in and around Haida Gwaii. We used the MFAST program to determine the polarization direction of the fast wave (φ) and the delay time (δt) between the fast and slow phases. The fast directions derived from stations on Haida Gwaii and two stations to the north on the Alaska Panhandle are predominantly margin-parallel (NNW). However, away from the plate boundary, the fast direction transitions to WSW-trending, very oblique or perpendicular to the plate boundary. Because the average delay time of 0.6-2.45 s is much larger than values based on an associated local S phase splitting analysis in the same study area, it is reasonable to infer that most of the anisotropy from our SKS analysis originates from the upper mantle and is associated with lattice-preferred orientation of anisotropic minerals. The margin-parallel fast direction within about 100 km of the QCF (average φ = -40º and δt = 1.2 s) is likely induced by the PA-NA shear motion. The roughly margin-normal fast directions farther away, although more scatterd, are consistent with that previously observed in the NA continent and are attributed to the absolute motion of the NA plate. However, the transition between the two regimes based on our SKS analysis appears to be gradual, suggesting that the plate boundary shear influences a much broader region at mantle depths than would be inferred from the surface trace of the QCF. We think this is due to the presence

  12. Assessment of seismic hazards along the northern Gulf of Aqaba

    Science.gov (United States)

    Abueladas, Abdel-Rahman Aqel

    Aqaba and Elat are very important port and recreation cities for the Hashemite Kingdom of Jordan and Israel, respectively. The two cities are the most susceptible to damage from a destructive future earthquake because they are located over the tectonically active Dead Sea transform fault (DST) that is the source of most of the major historical earthquakes in the region. The largest twentieth century earthquake on the DST, the magnitude Mw 7.2 Nuweiba earthquake of November 22, 1995, caused damage to structures in both cities. The integration of geological, geophysical, and earthquake engineering studies will help to assess the seismic hazards by determining the location and slip potential of active faults and by mapping areas of high liquefaction susceptibility. Ground Penetrating Radar (GPR) as a high resolution shallow geophysical tool was used to map the shallow active faults in Aqaba, Taba Sabkha area, and Elat. The GPR data revealed the onshore continuation of the Evrona, West Aqaba, Aqaba fault zones, and several transverse faults. The integration of offshore and onshore data confirm the extension of these faults along both sides of the Gulf of Aqaba. A 3D model of GPR data at one site in Aqaba indicates that the NW-trending transverse faults right laterally offset older than NE-trending faults. The most hazardous fault is the Evrona fault which extends north to the Tabs Sabkha. A geographic information system (GIS) database of the seismic hazard was created in order to facilitate the analyzing, manipulation, and updating of the input parameters. Liquefaction potential maps were created for the region based on analysis of borehole data. The liquefaction map shows high and moderate liquefaction susceptibility zones along the northern coast of the Gulf of Aqaba. In Aqaba several hotels are located within a high and moderate liquefaction zones. The Yacht Club, Aqaba, Ayla archaeological site, and a part of commercial area are also situated in a risk area. A part

  13. Seismic hazard assessment in intra-plate areas and backfitting

    International Nuclear Information System (INIS)

    Asmis, G.J.K.; Eng, P.

    2001-01-01

    Typically, fuel cycle facilities have been constructed over a 40 year time period incorporating various ages of seismic design provisions ranging from no specific seismic requirements to the life safety provisions normally incorporated in national building codes through to the latest seismic nuclear codes that provide not only for structural robustness but also include operational requirements for continued operation of essential safety functions. The task is to ensure uniform seismic risk in all facilities. Since the majority of the fuel cycle infrastructure has been built the emphasis is on re-evaluation and backfitting. The wide range of facilities included in the fuel cycle and the vastly varying hazard to safety, health and the environment suggest a performance based approach. This paper presents such an approach, placed in an intra-plate setting of a Stable Continental Region (SCR) typical to that found in Eastern Canada. (author)

  14. Subsea ice-bearing permafrost on the U.S. Beaufort Margin: 1. Minimum seaward extent defined from multichannel seismic reflection data

    Science.gov (United States)

    Brothers, Laura; Herman, Bruce M.; Hart, Patrick E.; Ruppel, Carolyn D.

    2016-01-01

    Subsea ice-bearing permafrost (IBPF) and associated gas hydrate in the Arctic have been subject to a warming climate and saline intrusion since the last transgression at the end of the Pleistocene. The consequent degradation of IBPF is potentially associated with significant degassing of dissociating gas hydrate deposits. Previous studies interpreted the distribution of subsea permafrost on the U.S. Beaufort continental shelf based on geographically sparse data sets and modeling of expected thermal history. The most cited work projects subsea permafrost to the shelf edge (∼100 m isobath). This study uses a compilation of stacking velocity analyses from ∼100,000 line-km of industry-collected multichannel seismic reflection data acquired over 57,000 km2 of the U.S. Beaufort shelf to delineate continuous subsea IBPF. Gridded average velocities of the uppermost 750 ms two-way travel time range from 1475 to 3110 m s−1. The monotonic, cross-shore pattern in velocity distribution suggests that the seaward extent of continuous IBPF is within 37 km of the modern shoreline at water depths < 25 m. These interpretations corroborate recent Beaufort seismic refraction studies and provide the best, margin-scale evidence that continuous subsea IBPF does not currently extend to the northern limits of the continental shelf.

  15. Seismic hazard assessment of the Three Gorges Project

    Directory of Open Access Journals (Sweden)

    Yao Yunsheng

    2013-05-01

    Full Text Available Seismic monitoring data for the past 50 years in the Three Gorges Reservoir area show that the reservoir head area is a typical weak seismic region with low seismicity before impoundment and that the epicenters were concentrated in the east and west sides of the Zigui Basin, most of which were natural tectonic earthquakes. After impoundment, the seismic activity shifted to the segment between Badong and Zigui along the Yangtze River, mainly within 5 km of the reservoir bank. The seismogenesis was categorized into four types; Karst collapse earthquakes, earthquakes caused by Karst gas explosion, mining tunnel collapse earthquakes, and rock (terrane slip earthquakes, all of which are related to the lithology, structure, and tectonics of near-surface geological bodies of the area. Compared with the seismicity before impoundment, the seismic frequency increase was remarkable, with most of the magnitudes below Ms2. 0. Therefore, the intensity of the earthquakes remained at a low level. On November 22, 2008, a magnitude 4. 1 earthquake, the largest earthquake recorded since impoundment, occurred in Quyuan Town, Zigui County. The intensity and PGA of reservoir-induced earthquakes are higher than those of tectonic earthquakes with equal magnitude, but the peak intensity of reservoir-induced earthquakes is not likely to go beyond that of the estimated range from earlier studies.

  16. Land-ocean tectonics (LOTs) and the associated seismic hazard over the Eastern Continental Margin of India (ECMI)

    Digital Repository Service at National Institute of Oceanography (India)

    Murthy, K.S.R.; Subrahmanyam, V.; Subrahmanyam, A.S.; Murty, G.P.S.; Sarma, K.V.L.N.S.

    , Subrahmanyam AS, Murty GPS, Murthy KSR (2009) Tectonic significance of Gundlakamma river (Krishna Basin) over Eastern Continental Margin of India – A qualitative appraisal (Communicated to Current Science) Subrahmanya K (1996) Active Intraplate deformation... for his suggestions to improve the MS. Thanks are also due to Miss.T.Madhavi for her help in preparing the illustrations This is N.I.O. (C.S.I.R.) contribution No. References Banerjee PK, Vaz VV, Sengupta BJ, Bagchi A (2001) A qualitative...

  17. New geological interpretation of multi-channel seismic profiles from the Pacific Margin of the Antarctic Peninsula

    Directory of Open Access Journals (Sweden)

    Okoń Jan

    2016-06-01

    Full Text Available The Polish Geophysical Expedition to West Antarctica in 1979–1980 was carried out by the Institute of Geophysics, Polish Academy of Sciences. Beside deep seismic soundings, 12 multi-channel seismic profiles, with a total length of ca 1000 km have been recorded north and east of the South Shetland Islands and in the Bransfield Strait, but they have never before been completely interpreted and published. All profiles have been processed with modern processing flow including time migration. Profiles crossing the South Shetland Trench revealed distinct reflector inside continental slope, which has been interpreted as border between buried accretionary prism and overlying slope sediments of glacial-marine origin. Profiles in the Bransfield Strait show traces of the Last Glacial Maximum (LGM in the form of glacial foreground valleys, with some of them used as weak spots for young age volcanic intrusions. This paper is the first comprehensive geological interpretation of collected dataset and differences between results from other expeditions are discussed.

  18. Assessment of the Metrological Performance of Seismic Tables for a QMS Recognition

    International Nuclear Information System (INIS)

    Ribeiro, A Silva; Costa, A Campos; Candeias, P; Martins, L Lages; Martins, A C Freitas; Ferreira, A C; Sousa, J Alves e

    2016-01-01

    Seismic testing and analysis using large infrastructures, such as shaking tables and reaction walls, is performed worldwide requiring the use of complex instrumentation systems. To assure the accuracy of these systems, conformity assessment is needed to verify the compliance with standards and applications, and the Quality Management Systems (QMS) is being increasingly applied to domains where risk analysis is critical as a way to provide a formal recognition. This paper describes an approach to the assessment of the metrological performance of seismic shake tables as part of a QMS recognition, with the analysis of a case study of LNEC Seismic shake table. (paper)

  19. Assessment of the Metrological Performance of Seismic Tables for a QMS Recognition

    Science.gov (United States)

    Silva Ribeiro, A.; Campos Costa, A.; Candeias, P.; Sousa, J. Alves e.; Lages Martins, L.; Freitas Martins, A. C.; Ferreira, A. C.

    2016-11-01

    Seismic testing and analysis using large infrastructures, such as shaking tables and reaction walls, is performed worldwide requiring the use of complex instrumentation systems. To assure the accuracy of these systems, conformity assessment is needed to verify the compliance with standards and applications, and the Quality Management Systems (QMS) is being increasingly applied to domains where risk analysis is critical as a way to provide a formal recognition. This paper describes an approach to the assessment of the metrological performance of seismic shake tables as part of a QMS recognition, with the analysis of a case study of LNEC Seismic shake table.

  20. Developing tools to identify marginal lands and assess their potential for bioenergy production

    Science.gov (United States)

    Galatsidas, Spyridon; Gounaris, Nikolaos; Dimitriadis, Elias; Rettenmaier, Nils; Schmidt, Tobias; Vlachaki, Despoina

    2017-04-01

    The term "marginal land" is currently intertwined in discussions about bioenergy although its definition is neither specific nor firm. The uncertainty arising from marginal land classification and quantification is one of the major constraining factors for its potential use. The clarification of political aims, i.e. "what should be supported?" is also an important constraining factor. Many approaches have been developed to identify marginal lands, based on various definitions according to the management goals. Concerns have been frequently raised regarding the impacts of marginal land use on environment, ecosystem services and sustainability. Current tools of soil quality and land potentials assessment fail to meet the needs of marginal land identification and exploitation for biomass production, due to the lack of comprehensive analysis of interrelated land functions and their quantitative evaluation. Land marginality is determined by dynamic characteristics in many cases and may therefore constitute a transitional state, which requires reassessment in due time. Also, marginal land should not be considered simply a dormant natural resource waiting to be used, since it may already provide multiple benefits and services to society relating to wildlife, biodiversity, carbon sequestration, etc. The consequences of cultivating such lands need to be fully addressed to present a balanced view of their sustainable potential for bioenergy. This framework is the basis for the development of the SEEMLA tools, which aim at supporting the identification, assessment, management of marginal lands in Europe and the decision-making for sustainable biomass production of them using appropriate bioenergy crops. The tools comprise two applications, a web-based one (independent of spatial data) and a GIS-based application (land regionalization on the basis of spatial data), which both incorporate: - Land resource characteristics, restricting the cultivation of agricultural crops but

  1. Seismic Hazard Assessment for a Characteristic Earthquake Scenario: Probabilistic-Deterministic Method

    Science.gov (United States)

    mouloud, Hamidatou

    2016-04-01

    The objective of this paper is to analyze the seismic activity and the statistical treatment of seismicity catalog the Constantine region between 1357 and 2014 with 7007 seismic event. Our research is a contribution to improving the seismic risk management by evaluating the seismic hazard in the North-East Algeria. In the present study, Earthquake hazard maps for the Constantine region are calculated. Probabilistic seismic hazard analysis (PSHA) is classically performed through the Cornell approach by using a uniform earthquake distribution over the source area and a given magnitude range. This study aims at extending the PSHA approach to the case of a characteristic earthquake scenario associated with an active fault. The approach integrates PSHA with a high-frequency deterministic technique for the prediction of peak and spectral ground motion parameters in a characteristic earthquake. The method is based on the site-dependent evaluation of the probability of exceedance for the chosen strong-motion parameter. We proposed five sismotectonique zones. Four steps are necessary: (i) identification of potential sources of future earthquakes, (ii) assessment of their geological, geophysical and geometric, (iii) identification of the attenuation pattern of seismic motion, (iv) calculation of the hazard at a site and finally (v) hazard mapping for a region. In this study, the procedure of the earthquake hazard evaluation recently developed by Kijko and Sellevoll (1992) is used to estimate seismic hazard parameters in the northern part of Algeria.

  2. Survey Methods for Seismic Vulnerability Assessment of Historical Masonry Buildings

    Science.gov (United States)

    Ballarin, M.; Balletti, C.; Faccio, P.; Guerra, F.; Saetta, A.; Vernier, P.

    2017-05-01

    On 20th and 29th of May 2012, two powerful earthquakes struck northern Italy. The epicentres were recorded respectively in Finale Emilia (magnitude 5.9 Ml) and Medolla (magnitude 5.8 Ml) in the province of Modena, though the earthquake was formed by a series of seismic shakes located in the district of the Emilian Po Valley, mainly in the provinces of Modena, Ferrara, Mantova, Reggio Emilia, Bologna and Rovigo. Many monuments in the city of Mantova were hit by the earthquake and, among these, Palazzo Ducale with the well-known Castello di San Giorgio which host the noteworthy "Camera degli Sposi". This building, the most famous of the city, was so damaged that it was closed for more than one year after the earthquake. The emblem of the Palace and Mantova itself, the previously cited "Camera degli Sposi" realized by Andrea Mantegna, was damaged and all the economic and social life of the city was deeply affected. Immediately after the earthquake, the Soprintendenza per i Beni Architettonici e Paesaggistici of Brescia, Cremona and Mantova establish an agreement with the University Iuav of Venice, requiring an analysis and assessment of the damage in order to proceed with the development of an intervention project. This activity turned out to be very important not only from the point of view of the recovery of the architectural and artistic heritage but also because the city's economy is based primarily on tourism. The closure of one of the most important monuments of Mantova has led to a significant and alarming decline in the government income.

  3. SURVEY METHODS FOR SEISMIC VULNERABILITY ASSESSMENT OF HISTORICAL MASONRY BUILDINGS

    Directory of Open Access Journals (Sweden)

    M. Ballarin

    2017-05-01

    Full Text Available On 20th and 29th of May 2012, two powerful earthquakes struck northern Italy. The epicentres were recorded respectively in Finale Emilia (magnitude 5.9 Ml and Medolla (magnitude 5.8 Ml in the province of Modena, though the earthquake was formed by a series of seismic shakes located in the district of the Emilian Po Valley, mainly in the provinces of Modena, Ferrara, Mantova, Reggio Emilia, Bologna and Rovigo. Many monuments in the city of Mantova were hit by the earthquake and, among these, Palazzo Ducale with the well-known Castello di San Giorgio which host the noteworthy “Camera degli Sposi”. This building, the most famous of the city, was so damaged that it was closed for more than one year after the earthquake. The emblem of the Palace and Mantova itself, the previously cited “Camera degli Sposi” realized by Andrea Mantegna, was damaged and all the economic and social life of the city was deeply affected. Immediately after the earthquake, the Soprintendenza per i Beni Architettonici e Paesaggistici of Brescia, Cremona and Mantova establish an agreement with the University Iuav of Venice, requiring an analysis and assessment of the damage in order to proceed with the development of an intervention project. This activity turned out to be very important not only from the point of view of the recovery of the architectural and artistic heritage but also because the city's economy is based primarily on tourism. The closure of one of the most important monuments of Mantova has led to a significant and alarming decline in the government income.

  4. Multi-Hazard Advanced Seismic Probabilistic Risk Assessment Tools and Applications

    International Nuclear Information System (INIS)

    Coleman, Justin L.; Bolisetti, Chandu; Veeraraghavan, Swetha; Parisi, Carlo; Prescott, Steven R.; Gupta, Abhinav

    2016-01-01

    Design of nuclear power plant (NPP) facilities to resist natural hazards has been a part of the regulatory process from the beginning of the NPP industry in the United States (US), but has evolved substantially over time. The original set of approaches and methods was entirely deterministic in nature and focused on a traditional engineering margins-based approach. However, over time probabilistic and risk-informed approaches were also developed and implemented in US Nuclear Regulatory Commission (NRC) guidance and regulation. A defense-in-depth framework has also been incorporated into US regulatory guidance over time. As a result, today, the US regulatory framework incorporates deterministic and probabilistic approaches for a range of different applications and for a range of natural hazard considerations. This framework will continue to evolve as a result of improved knowledge and newly identified regulatory needs and objectives, most notably in response to the NRC activities developed in response to the 2011 Fukushima accident in Japan. Although the US regulatory framework has continued to evolve over time, the tools, methods and data available to the US nuclear industry to meet the changing requirements have not kept pace. Notably, there is significant room for improvement in the tools and methods available for external event probabilistic risk assessment (PRA), which is the principal assessment approach used in risk-informed regulations and risk-informed decision-making applied to natural hazard assessment and design. This is particularly true if PRA is applied to natural hazards other than seismic loading. Development of a new set of tools and methods that incorporate current knowledge, modern best practice, and state-of-the-art computational resources would lead to more reliable assessment of facility risk and risk insights (e.g., the SSCs and accident sequences that are most risk-significant), with less uncertainty and reduced conservatisms.

  5. Multi-Hazard Advanced Seismic Probabilistic Risk Assessment Tools and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, Justin L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bolisetti, Chandu [Idaho National Lab. (INL), Idaho Falls, ID (United States); Veeraraghavan, Swetha [Idaho National Lab. (INL), Idaho Falls, ID (United States); Parisi, Carlo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Prescott, Steven R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gupta, Abhinav [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    Design of nuclear power plant (NPP) facilities to resist natural hazards has been a part of the regulatory process from the beginning of the NPP industry in the United States (US), but has evolved substantially over time. The original set of approaches and methods was entirely deterministic in nature and focused on a traditional engineering margins-based approach. However, over time probabilistic and risk-informed approaches were also developed and implemented in US Nuclear Regulatory Commission (NRC) guidance and regulation. A defense-in-depth framework has also been incorporated into US regulatory guidance over time. As a result, today, the US regulatory framework incorporates deterministic and probabilistic approaches for a range of different applications and for a range of natural hazard considerations. This framework will continue to evolve as a result of improved knowledge and newly identified regulatory needs and objectives, most notably in response to the NRC activities developed in response to the 2011 Fukushima accident in Japan. Although the US regulatory framework has continued to evolve over time, the tools, methods and data available to the US nuclear industry to meet the changing requirements have not kept pace. Notably, there is significant room for improvement in the tools and methods available for external event probabilistic risk assessment (PRA), which is the principal assessment approach used in risk-informed regulations and risk-informed decision-making applied to natural hazard assessment and design. This is particularly true if PRA is applied to natural hazards other than seismic loading. Development of a new set of tools and methods that incorporate current knowledge, modern best practice, and state-of-the-art computational resources would lead to more reliable assessment of facility risk and risk insights (e.g., the SSCs and accident sequences that are most risk-significant), with less uncertainty and reduced conservatisms.

  6. The value of breast lumpectomy margin assessment as a predictor of residual tumor burden

    International Nuclear Information System (INIS)

    Wazer, David E.; Schmidt-Ullrich, Rupert K.; Schmid, Christopher H.; Ruthazer, Robin; Kramer, Bradley; Safaii, Homa; Graham, Roger

    1997-01-01

    Purpose: Margin assessment is commonly used as a guide to the relative aggressiveness of therapy for breast conserving treatment (BCT), though its value as a predictor of the presence, type, or extent of residual tumor has not been conclusively studied. Controversy continues to exist as to what constitutes a margin that is 'positive', 'close', or 'negative'. We attempt to address these issues through an analysis of re-excision specimens. Patients and Methods: As part of an institutional prospective practice approach for BCT, 265 cases with AJCC Stage I/II carcinoma with an initial excision margin that was ≤2 mm or indeterminate were subjected to re-excision. The probability of residual tumor (+RE) was evaluated with respect to tumor size, histopathologic subtype, relative closeness of the measured margin, the extent of margin positivity graded as focal, minimal, moderate, or extensive, and the extent of specimen processing as reflected in the number of cut sections per specimen volume (S:V ratio). The amount of residual tumor was graded as microscopic, small, medium, or large. The histopathologic subtype of tumor in the re-excision specimen was classified as having an invasive component (ICa) or pure DCIS (DCIS). Results: The primary excision margin was positive, >0≤1 mm, 1.1-2 mm, and indeterminate in 60%, 18%, 5%, and 17%, respectively. The predominant histopathologies in the initial excision specimens were invasive ductal (IDC) (50%) and tumors with an extensive intraductal component (EIC) (43%). The histopathology of the initial excision specimen was highly predictive of the histopathology of tumor found on re-excision, as residual DCIS was found in 60% of +RE specimens with initial histopathology of EIC compared to 26% for IDC (p 0.001). Neither the extent of margin positivity nor the extent of tumor in the re-excision were significantly related to the initial histopathologic subtype; however, a +RE was seen in 59% of EIC, 43% of IDC, and 32% of invasive

  7. Social Media as Seismic Networks for the Earthquake Damage Assessment

    Science.gov (United States)

    Meletti, C.; Cresci, S.; La Polla, M. N.; Marchetti, A.; Tesconi, M.

    2014-12-01

    The growing popularity of online platforms, based on user-generated content, is gradually creating a digital world that mirrors the physical world. In the paradigm of crowdsensing, the crowd becomes a distributed network of sensors that allows us to understand real life events at a quasi-real-time rate. The SoS-Social Sensing project [http://socialsensing.it/] exploits the opportunistic crowdsensing, involving users in the sensing process in a minimal way, for social media emergency management purposes in order to obtain a very fast, but still reliable, detection of emergency dimension to face. First of all we designed and implemented a decision support system for the detection and the damage assessment of earthquakes. Our system exploits the messages shared in real-time on Twitter. In the detection phase, data mining and natural language processing techniques are firstly adopted to select meaningful and comprehensive sets of tweets. Then we applied a burst detection algorithm in order to promptly identify outbreaking seismic events. Using georeferenced tweets and reported locality names, a rough epicentral determination is also possible. The results, compared to Italian INGV official reports, show that the system is able to detect, within seconds, events of a magnitude in the region of 3.5 with a precision of 75% and a recall of 81,82%. We then focused our attention on damage assessment phase. We investigated the possibility to exploit social media data to estimate earthquake intensity. We designed a set of predictive linear models and evaluated their ability to map the intensity of worldwide earthquakes. The models build on a dataset of almost 5 million tweets exploited to compute our earthquake features, and more than 7,000 globally distributed earthquakes data, acquired in a semi-automatic way from USGS, serving as ground truth. We extracted 45 distinct features falling into four categories: profile, tweet, time and linguistic. We run diagnostic tests and

  8. Seismic assessment of Kozloduy VVER 440, Model 230 nuclear power plant

    International Nuclear Information System (INIS)

    Monette, P.; Baltus, R.; Yanev, P.; Campbell, R.

    1991-01-01

    Excluding system design deficiency relative to US and Western Europe standards, it was found that the plant has many seismic vulnerabilities similar to those that existed in many of the US plants prior to about 1979 when the Systematic Evaluation Program was initiated. The primary coolant system has been substantially upgraded after the 1977 Vrancea earthquake. Other upgrades have been made to weak elements in the ECCS and electrical systems. There are still a number of components that could likely survive the currently defined Safe Shutdown Earthquake of 0.1 g but which would not meet current design standards. Many of the weakest components could be upgraded at a moderate cost to withstand a seismic event exceeding 0.1 g. Current studies of the site seismicity lean toward a higher peak ground acceleration and increased amplification of building motion, thus backfits that have been accomplished may become marginal for newly defined loads. However the proper consideration of soil structure interaction and detailed structural analysis using less conservative modeling assumptions, could mitigate the impact of increasing the seismic input and limit the amount of reinforcement required. In the interim, substantial improvements to seismic safety could be accomplished by simple, inexpensive modifications to equipment anchorage and some achievable improvements to connection detail of the precast concrete structures. (author)

  9. Correspondence between conventional and digitised radiographs for assessment of marginal bone.

    Science.gov (United States)

    Bahrami, Golnosh; Isidor, Flemming; Wenzel, Ann; Vaeth, Michael

    2013-01-01

    To compare reproducibility of marginal bone measurements in conventional film and digitised radiographs and to assess whether variations in reproducibility occurred in measurements taken in a longitudinal, epidemiological survey. Triplicate measurements of the marginal bone level and of remaining bone were obtained from film and digitised full-mouth radiographic surveys from 20 individuals who were examined three times at five-year intervals in a longitudinal study design. The digitalisation of the films was conducted by scanning the film with a flatbed scanner. The standard deviation (SD) of the triplicate measurements served as the statistic for reproducibility. The time spent for recording one radiographic survey, which consisted of 14 periapicals and 2 bitewings, was documented. Statistically significant differences existed in the reproducibility of marginal bone level measurements obtained at the first examination and the two subsequent examinations both for film and digitised radiographs (P < 0.05). The difference in marginal bone level measurements (film vs digitised) was 0.16 mm (SD = 0.45 mm). Similarly, the overall difference in measurements of the remaining bone was 0.12 mm (SD = 0.61 mm). Recording of a digitised survey lasted on average 5 min (SD = 1.5 min), while the recording of a film survey lasted on average 14 min (SD = 1 min). Digitising film is an acceptable method for the purpose of assessing the marginal bone level and will save time in longitudinal, epidemiological studies.

  10. Seismic waves in 3-D: from mantle asymmetries to reliable seismic hazard assessment

    Science.gov (United States)

    Panza, Giuliano F.; Romanelli, Fabio

    2014-10-01

    A global cross-section of the Earth parallel to the tectonic equator (TE) path, the great circle representing the equator of net lithosphere rotation, shows a difference in shear wave velocities between the western and eastern flanks of the three major oceanic rift basins. The low-velocity layer in the upper asthenosphere, at a depth range of 120 to 200 km, is assumed to represent the decoupling between the lithosphere and the underlying mantle. Along the TE-perturbed (TE-pert) path, a ubiquitous LVZ, about 1,000-km-wide and 100-km-thick, occurs in the asthenosphere. The existence of the TE-pert is a necessary prerequisite for the existence of a continuous global flow within the Earth. Ground-shaking scenarios were constructed using a scenario-based method for seismic hazard analysis (NDSHA), using realistic and duly validated synthetic time series, and generating a data bank of several thousands of seismograms that account for source, propagation, and site effects. Accordingly, with basic self-organized criticality concepts, NDSHA permits the integration of available information provided by the most updated seismological, geological, geophysical, and geotechnical databases for the site of interest, as well as advanced physical modeling techniques, to provide a reliable and robust background for the development of a design basis for cultural heritage and civil infrastructures. Estimates of seismic hazard obtained using the NDSHA and standard probabilistic approaches are compared for the Italian territory, and a case-study is discussed. In order to enable a reliable estimation of the ground motion response to an earthquake, three-dimensional velocity models have to be considered, resulting in a new, very efficient, analytical procedure for computing the broadband seismic wave-field in a 3-D anelastic Earth model.

  11. Scenario based seismic hazard assessment and its application to the seismic verification of relevant buildings

    Science.gov (United States)

    Romanelli, Fabio; Vaccari, Franco; Altin, Giorgio; Panza, Giuliano

    2016-04-01

    The procedure we developed, and applied to a few relevant cases, leads to the seismic verification of a building by: a) use of a scenario based neodeterministic approach (NDSHA) for the calculation of the seismic input, and b) control of the numerical modeling of an existing building, using free vibration measurements of the real structure. The key point of this approach is the strict collaboration, from the seismic input definition to the monitoring of the response of the building in the calculation phase, of the seismologist and the civil engineer. The vibrometry study allows the engineer to adjust the computational model in the direction suggested by the experimental result of a physical measurement. Once the model has been calibrated by vibrometric analysis, one can select in the design spectrum the proper range of periods of interest for the structure. Then, the realistic values of spectral acceleration, which include the appropriate amplification obtained through the modeling of a "scenario" input to be applied to the final model, can be selected. Generally, but not necessarily, the "scenario" spectra lead to higher accelerations than those deduced by taking the spectra from the national codes (i.e. NTC 2008, for Italy). The task of the verifier engineer is to act so that the solution of the verification is conservative and realistic. We show some examples of the application of the procedure to some relevant (e.g. schools) buildings of the Trieste Province. The adoption of the scenario input has given in most of the cases an increase of critical elements that have to be taken into account in the design of reinforcements. However, the higher cost associated with the increase of elements to reinforce is reasonable, especially considering the important reduction of the risk level.

  12. Excavatability Assessment of Weathered Sedimentary Rock Mass Using Seismic Velocity Method

    International Nuclear Information System (INIS)

    Bin Mohamad, Edy Tonnizam; Noor, Muhazian Md; Isa, Mohamed Fauzi Bin Md.; Mazlan, Ain Naadia; Saad, Rosli

    2010-01-01

    Seismic refraction method is one of the most popular methods in assessing surface excavation. The main objective of the seismic data acquisition is to delineate the subsurface into velocity profiles as different velocity can be correlated to identify different materials. The physical principal used for the determination of excavatability is that seismic waves travel faster through denser material as compared to less consolidated material. In general, a lower velocity indicates material that is soft and a higher velocity indicates more difficult to be excavated. However, a few researchers have noted that seismic velocity method alone does not correlate well with the excavatability of the material. In this study, a seismic velocity method was used in Nusajaya, Johor to assess the accuracy of this seismic velocity method with excavatability of the weathered sedimentary rock mass. A direct ripping run by monitoring the actual production of ripping has been employed at later stage and compared to the ripper manufacturer's recommendation. This paper presents the findings of the seismic velocity tests in weathered sedimentary area. The reliability of using this method with the actual rippability trials is also presented.

  13. Excavatability Assessment of Weathered Sedimentary Rock Mass Using Seismic Velocity Method

    Science.gov (United States)

    Bin Mohamad, Edy Tonnizam; Saad, Rosli; Noor, Muhazian Md; Isa, Mohamed Fauzi Bin Md.; Mazlan, Ain Naadia

    2010-12-01

    Seismic refraction method is one of the most popular methods in assessing surface excavation. The main objective of the seismic data acquisition is to delineate the subsurface into velocity profiles as different velocity can be correlated to identify different materials. The physical principal used for the determination of excavatability is that seismic waves travel faster through denser material as compared to less consolidated material. In general, a lower velocity indicates material that is soft and a higher velocity indicates more difficult to be excavated. However, a few researchers have noted that seismic velocity method alone does not correlate well with the excavatability of the material. In this study, a seismic velocity method was used in Nusajaya, Johor to assess the accuracy of this seismic velocity method with excavatability of the weathered sedimentary rock mass. A direct ripping run by monitoring the actual production of ripping has been employed at later stage and compared to the ripper manufacturer's recommendation. This paper presents the findings of the seismic velocity tests in weathered sedimentary area. The reliability of using this method with the actual rippability trials is also presented.

  14. AECB workshop on seismic hazard assessment in Southern Ontario. Recorded proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    A workshop on seismic hazard assessment in southern Ontario was conducted on June 19-21, 1995. The purpose of the workshop was to review available geological and seismological data which could affect earthquake occurrence in southern Ontario and to develop a consensus on approaches that should be adopted for characterization of seismic hazard. The workshop was structured in technical sessions to focus presentations and discussions on four technical issues relevant to seismic hazard in southern Ontario, as follows: The importance of geological and geophysical observations for the determination of seismic sources; Methods and approaches which may be adopted for determining seismic sources based on integrated interpretations of geological and seismological information. Methods and data which should be used for characterizing the seismicity parameters of seismic sources. Methods for assessment of vibratory ground motion hazard. This document presents transcripts from recordings made of the presentations and discussion from the workshop. It will be noted, in some sections of the document, that the record is incomplete. This is due in part to recording equipment malfunction and in part due to the poor quality of recording obtained for certain periods.

  15. AECB workshop on seismic hazard assessment in Southern Ontario. Recorded proceedings

    International Nuclear Information System (INIS)

    1995-01-01

    A workshop on seismic hazard assessment in southern Ontario was conducted on June 19-21, 1995. The purpose of the workshop was to review available geological and seismological data which could affect earthquake occurrence in southern Ontario and to develop a consensus on approaches that should be adopted for characterization of seismic hazard. The workshop was structured in technical sessions to focus presentations and discussions on four technical issues relevant to seismic hazard in southern Ontario, as follows: The importance of geological and geophysical observations for the determination of seismic sources; Methods and approaches which may be adopted for determining seismic sources based on integrated interpretations of geological and seismological information. Methods and data which should be used for characterizing the seismicity parameters of seismic sources. Methods for assessment of vibratory ground motion hazard. This document presents transcripts from recordings made of the presentations and discussion from the workshop. It will be noted, in some sections of the document, that the record is incomplete. This is due in part to recording equipment malfunction and in part due to the poor quality of recording obtained for certain periods

  16. ASSESSMENT OF THE TSUNAMIGENIC POTENTIAL ALONG THE NORTHERN CARIBBEAN MARGIN Case Study: Earthquake and Tsunamis of 12 January 2010 in Haiti.

    Directory of Open Access Journals (Sweden)

    George Pararas-Carayannis

    2010-01-01

    Full Text Available The potential tsunami risk for Hispaniola, as well as for the other Greater Antilles Islands is assessed by reviewing the complex geotectonic processes and regimes along the Northern Caribbean margin, including the convergent, compressional and collisional tectonic activity of subduction, transition, shearing, lateral movements, accretion and crustal deformation caused by the eastward movement of the Caribbean plate in relation to the North American plate. These complex tectonic interactions have created a broad, diffuse tectonic boundary that has resulted in an extensive, internal deformational sliver slab - the Gonâve microplate – as well as further segmentation into two other microplates with similarly diffused boundary characteristics where tsunamigenic earthquakes have and will again occur. The Gonâve microplate is the most prominent along the Northern Caribbean margin and extends from the Cayman Spreading Center to Mona Pass, between Puerto Rico and the island of Hispaniola, where the 1918 destructive tsunami was generated. The northern boundary of this sliver microplate is defined by the Oriente strike-slip fault south of Cuba, which appears to be an extension of the fault system traversing the northern part of Hispaniola, while the southern boundary is defined by another major strike-slip fault zone where the Haiti earthquake of 12 January 2010 occurred. Potentially tsunamigenic regions along the Northern Caribbean margin are located not only along the boundaries of the Gonâve microplate’s dominant western transform zone but particularly within the eastern tectonic regimes of the margin where subduction is dominant - particularly along the Puerto Rico trench. The Haiti earthquake of 12 January 2010 and its focal mechanism are examined, as they provide additional clues of potential tsunami generation that can occur along transform zones and, more specifically, from interplate and intraplate seismic events and subsequently induced

  17. Assessing Mediation Using Marginal Structural Models in the Presence of Confounding and Moderation

    Science.gov (United States)

    Coffman, Donna L.; Zhong, Wei

    2012-01-01

    This article presents marginal structural models with inverse propensity weighting (IPW) for assessing mediation. Generally, individuals are not randomly assigned to levels of the mediator. Therefore, confounders of the mediator and outcome may exist that limit causal inferences, a goal of mediation analysis. Either regression adjustment or IPW…

  18. The Contribution of Palaeoseismology to Seismic Hazard Assessment in Site Evaluation for Nuclear Installations

    International Nuclear Information System (INIS)

    2015-06-01

    IAEA Safety Standards Series No. SSG-9, Seismic Hazards in Site Evaluation for Nuclear Installations, published in 2010, covers all aspects of site evaluation relating to seismic hazards and recommends the use of prehistoric, historical and instrumental earthquake data in seismic hazard assessments. Prehistoric data on earthquakes cover a much longer period than do historical and instrumental data. However, gathering such data is generally difficult in most regions of the world, owing to an absence of human records. Prehistoric data on earthquakes can be obtained through the use of palaeoseismic techniques. This publication describes the current status and practices of palaeoseismology, in order to support Member States in meeting the recommendations of SSG-9 and in establishing the necessary earthquake related database for seismic hazard assessment and reassessment. At a donors’ meeting of the International Seismic Safety Centre Extrabudgetary Project in January 2011, it was suggested to develop detailed guidelines on seismic hazards. Soon after the meeting, the disastrous Great East Japan Earthquake and Tsunami of 11 March 2011 and the consequent accident at the Fukushima Daiichi nuclear power plant occurred. The importance of palaeoseismology for seismic hazard assessment in site evaluation was highlighted by the lessons learned from the Fukushima Daiichi nuclear power plant accident. However, no methodology for performing investigations using palaeoseismic techniques has so far been available in an IAEA publication. The detailed guidelines and practical tools provided here will be of value to nuclear power plant operating organizations, regulatory bodies, vendors, technical support organizations and researchers in the area of seismic hazard assessment in site evaluation for nuclear installations, and the information will be of importance in support of hazard assessments in the future

  19. ASSESSMENT OF IMPORTANT SEISMIC PROVISIONS OF EBCS 8 ...

    African Journals Online (AJOL)

    resistant design of structures in Ethiopia have been made available since the' time of release of the three-volume. Ethiopian Standard Code of Practice (ESCP) in. 1983. The seismic provisions in this code occupied only few pages in the small volume for loading,. 'ESCP 1, and were limited to pseudo-static analysis.

  20. Seismic assessment of the Pickering pressure relief duct

    International Nuclear Information System (INIS)

    Ghobarah, A.

    1995-05-01

    The objectives of the study are to examine the structural response of the Pickering pressure relief duct when subjected to earthquake ground motion and to estimate the seismic withstand capacity of various components of the structural system on the basis of performance criteria consistent with the safety function of the duct. (author). 24 refs., 16 tabs., 31 figs

  1. Development of fragility descriptions of equipment for seismic risk assessment of nuclear power plants

    International Nuclear Information System (INIS)

    Hardy, G.S.; Campbell, R.D.

    1983-01-01

    Probabilistic risk assessment (PRA) of a nuclear power plant for postulated hazard requires the development of fragility relationships for the plants' safety related equipment. The objective of this paper is to present some general results and conclusions concerning the development of these seismic fragility levels. Participation in fragility-related research and experience gained from the completion of several PRA studies of a variety of nuclear power plants have provided much insight as to the most vulnerable equipment and the most efficient use of resources for development of fragilities. Plants studied had seismic design bases ranging from very simple equivalent static analysis for some of the earlier plants to state-of-the-art complex multimode dyanamic analyses for plants currently under construction. Increased sophistication and rigor in seismic qualification of equipment has resulted for the most part in increased seismic resistance. The majority of equipment has been found, however, to possess more than adequate resistance to seismic loading regardless of the degree of sophistication utilized in design as long as seismic loading was included in the design process. This paper presents conclusions of the authors as to which items of equipment typically require an individual ''plant-specific'' fragility analysis and which can be treated in a generic fashion. In addition, general conclusions on the relative seismic capacity levels and most frequent failure modes are summarized for generic equipment groups

  2. Towards intraoperative assessment of tumor margins in breast surgery using optical coherence elastography (Conference Presentation)

    Science.gov (United States)

    Kennedy, Brendan F.; Wijesinghe, Philip; Allen, Wes M.; Chin, Lixin; Latham, Bruce; Saunders, Christobel M.; Sampson, David D.

    2016-03-01

    Surgical excision of tumor is a critical factor in the management of breast cancer. The most common surgical procedure is breast-conserving surgery. The surgeon's goal is to remove the tumor and a rim of healthy tissue surrounding the tumor: the surgical margin. A major issue in breast-conserving surgery is the absence of a reliable tool to guide the surgeon in intraoperatively assessing the margin. A number of techniques have been proposed; however, the re-excision rate remains high and has been reported to be in the range 30-60%. New tools are needed to address this issue. Optical coherence elastography (OCE) shows promise as a tool for intraoperative tumor margin assessment in breast-conserving surgery. Further advances towards clinical translation are limited by long scan times and small fields of view. In particular, scanning over sufficient areas to assess the entire margin in an intraoperative timeframe has not been shown to be feasible. Here, we present a protocol allowing ~75% of the surgical margins to be assessed within 30 minutes. To achieve this, we have incorporated a 65 mm-diameter (internal), wide-aperture annular piezoelectric transducer, allowing the entire surface of the excised tumor mass to be automatically imaged in an OCT mosaic comprised of 10 × 10 mm tiles. As OCT is effective in identifying adipose tissue, our protocol uses the wide-field OCT to selectively guide subsequent local OCE scanning to regions of solid tissue which often present low contrast in OCT images. We present promising examples from freshly excised human breast tissue.

  3. Seismic investigations of the Earth's lithosphere and asthenosphere in two unique convergent margin settings: The Carpathians, Romania, and U.S. Cordillera, Idaho-Oregon

    Science.gov (United States)

    Stanciu, Adrian Christian

    Proposed mechanisms for the unusual seismicity ~100 km southeast of the contact between the Transylvanian Basin and the Eastern Carpathians in Romania have included tearing and rollback of a subducted slab of oceanic lithosphere and gravitational instability and delamination of continental lithosphere. We examined the upper mantle fabrics using shear wave splitting of SK(K)S phases recorded at four broadband seismic stations in the Transylvanian Basin. Our results indicate a regional NW-SE splitting trend, with measurements that reflect an abrupt change from this regional flow field in the vicinity of the Vrancea body to a NE-SW trend that is consistent with redirection of mantle flow. Crustal thickness measurements show 28-30 km in the western part of the Transylvanian Basin, 34-39 km at the contact with the Eastern Carpathians, and 40-45 km further east. These results, along with previous estimates, constrain the locus of the inferred Miocene suture between the southeastern-most portion of the Tisza-Dacia terrane and the East European Platform. The second convergent margin system represented here is in the North American Cordillera in Idaho and Oregon, where subduction and accretion of exotic terranes have modified the western margin of North America. We used teleseismic receiver functions from 85 broadband stations to analyze the geometry of the Salmon River suture zone, the western Idaho shear zone, and the Grouse Creek-Farmington zone boundary. Results show a clear break in crustal thickness from ~28 km beneath the accreted terranes to 36 km east of the surface expression of the WISZ. A strong mid-crustal converter at ~20 km depth is consistent with tectonic wedging during accretion of the Blue Mountains terranes. An eastern Moho offset of ~6 km is consistent with the Archean Grouse Creek-Farmington zone boundary. We used deep converted phases generated beneath the study area to image the mantle transition zone. We observe a continuous high amplitude P410s

  4. Development of seismic damage assessment system for nuclear power plant structures in Korea

    International Nuclear Information System (INIS)

    Hyun, Chang-Hun; Lee, Sung-Kyu; Choi, Kang-Ryoung; Koh, Hyun-Moo; Cho, HoHyun

    2003-01-01

    A seismic damage assessment system that analyses in real-time the actual seismic resistance capacity and the damage level of power plant structures has been developed. The system consists of three parts: a 3-D inelastic seismic analysis, a damage assessment using a damage index based on the previous 3-D analysis, and a 3-D graphic representation. PSC containment structures are modelled by finite shell elements using layered method and analysis is performed by means of time history inelastic seismic analysis method, which takes into account material nonlinearities. HHT-α, one kind of direct integration method, is adopted for the seismic analysis. Two damage indices at finite element and structural levels are applied for the seismic damage assessment. 3-D graphical representation of dynamic responses and damage index expedites procedure for evaluating the damage level. The developed system is now being installed at the Earthquake Monitoring Center of KINS (Korea Institute of Nuclear Safety) to support site inspections after an earthquake occurrence, and decisions about effective emergency measures, repair and operations of the plant. (author)

  5. Seismic Refraction & Wide-angle Reflection Experiment on the Northern Margin of North China Craton -Data Acquisition and Preliminary Processing Result

    Science.gov (United States)

    Li, W.; Gao, R.; Keller, G. R.; Hou, H.; Li, Q.; Cox, C. M.; Chang, J. C.; Zhang, J.; Guan, Y.

    2010-12-01

    The evolution history of Central Asian Orogen Belt (CAOB) is still the main tectonic problems in northeastern Asia. The Siberia Craton (NC), North China Craton (NCC) and several blocks collided, and the resulting tectonic collage formed as the Paleo-Asian Ocean disappeared. Concerning the northern margin of North China Craton, many different geological questions remain unanswered, such as: the intracontinental orogenic process in the Yanshan orogen and the nature and location of the suture between the southern NC and the northern NCC. In Dec 2009, a 400 km long seismic refraction and wide-angle reflection profile was completed jointly by Institute of Geology, CAGS and University of Oklahoma. The survey line extended from the west end of the Yanshan orogen, across a granitoid belt to the Solonker suture zone. The recording of seismic waves from 8 explosions (500~1500 kg each) was conducted in four deployments of 300 Reftek125 (Texan) seismic recorders, with an average spacing of 1 km. For the calculations, we used the Rayinvr, Vmed and Zplot programs for ray tracing, model modification and phase picking. The initial result show that: 1)the depth of low velocity sediment cover ranges from 0.6 to 2.7 km (velocity: 2.8~5.6 km/s); 2)the depth of basement is 5.6~10 km (the depth of basement under the granitoid belt deepens to 10 km and velocity increases to 6.2 km/s); 3)the upper crust extends to a depth of 15.5~21 km and has the P-wave velocities between 5.6 and 6.4 km/s; 4)the thickness of the lower crust ranges from 22~28 km(velocity: 6.4~6.9 km/s); and 5)the depth of Moho varies from 39.5 km under the granitoid belt to 49 km under the Yanshan orogen. Based on these results, we can preliminarily deduce that: 1) the concave depression of the Moho observed represents the root of the Yanshan orogen, and it may prove that the orogen is dominated by thick-skinned tectonics; 2) the shape of velocity variations under the granitoid belt is suggestive of a magma conduit. It

  6. The Spatial Assessment of the Current Seismic Hazard State for Hard Rock Underground Mines

    Science.gov (United States)

    Wesseloo, Johan

    2018-06-01

    Mining-induced seismic hazard assessment is an important component in the management of safety and financial risk in mines. As the seismic hazard is a response to the mining activity, it is non-stationary and variable both in space and time. This paper presents an approach for implementing a probabilistic seismic hazard assessment to assess the current hazard state of a mine. Each of the components of the probabilistic seismic hazard assessment is considered within the context of hard rock underground mines. The focus of this paper is the assessment of the in-mine hazard distribution and does not consider the hazard to nearby public or structures. A rating system and methodologies to present hazard maps, for the purpose of communicating to different stakeholders in the mine, i.e. mine managers, technical personnel and the work force, are developed. The approach allows one to update the assessment with relative ease and within short time periods as new data become available, enabling the monitoring of the spatial and temporal change in the seismic hazard.

  7. Assessment of Quantitative Aftershock Productivity Potential in Mining-Induced Seismicity

    Science.gov (United States)

    Kozłowska, Maria; Orlecka-Sikora, Beata

    2017-03-01

    Strong mining-induced earthquakes exhibit various aftershock patterns. The aftershock productivity is governed by the geomechanical properties of rock in the seismogenic zone, mining-induced stress and coseismic stress changes related to the main shock's magnitude, source geometry and focal mechanism. In order to assess the quantitative aftershock productivity potential in the mining environment we apply a forecast model based on natural seismicity properties, namely constant tectonic loading and the Gutenberg-Richter frequency-magnitude distribution. Although previous studies proved that mining-induced seismicity does not obey the simple power law, here we apply it as an approximation of seismicity distribution to resolve the number of aftershocks, not considering their magnitudes. The model used forecasts the aftershock productivity based on the background seismicity level estimated from an average seismic moment released per earthquake and static stress changes caused by a main shock. Thus it accounts only for aftershocks directly triggered by coseismic process. In this study we use data from three different mines, Mponeng (South Africa), Rudna and Bobrek (Poland), representing different geology, exploitation methods and aftershock patterns. Each studied case is treated with individual parameterization adjusted to the data specifics. We propose the modification of the original model, i.e. including the non-uniformity of M 0, resulting from spatial correlation of mining-induced seismicity with exploitation. The results show that, even when simplified seismicity distribution parameters are applied, the modified model predicts the number of aftershocks for each analyzed case well and accounts for variations between these values. Such results are thus another example showing that coseismic processes of mining-induced seismicity reflect features of natural seismicity and that similar models can be applied to study the aftershock rate in both the natural and the

  8. Marginal Generation Technology in the Chinese Power Market towards 2030 Based on Consequential Life Cycle Assessment

    Directory of Open Access Journals (Sweden)

    Guangling Zhao

    2016-09-01

    Full Text Available Electricity consumption is often the hotspot of life cycle assessment (LCA of products, industrial activities, or services. The objective of this paper is to provide a consistent, scientific, region-specific electricity-supply-based inventory of electricity generation technology for national and regional power grids. Marginal electricity generation technology is pivotal in assessing impacts related to additional consumption of electricity. China covers a large geographical area with regional supply grids; these are arguably equally or less integrated. Meanwhile, it is also a country with internal imbalances in regional energy supply and demand. Therefore, we suggest an approach to achieve a geographical subdivision of the Chinese electricity grid, corresponding to the interprovincial regional power grids, namely the North, the Northeast, the East, the Central, the Northwest, and the Southwest China Grids, and the China Southern Power Grid. The approach combines information from the Chinese national plans on for capacity changes in both production and distribution grids, and knowledge of resource availability. The results show that nationally, marginal technology is coal-fired electricity generation, which is the same scenario in the North and Northwest China Grid. In the Northeast, East, and Central China Grid, nuclear power gradually replaces coal-fired electricity and becomes the marginal technology. In the Southwest China Grid and the China Southern Power Grid, the marginal electricity is hydropower towards 2030.

  9. Current methodologies for assessing seismically induced settlements in soil

    International Nuclear Information System (INIS)

    Ledbetter, R.

    1983-08-01

    Earthquake-induced surface settlements have ranged from 0.7 to 10 percent of layer thickness for the relatively few incidences where reliable estimates have been made of settlement magnitudes and soil conditions. Standard penetration test results obtained for pre-earthquake and postearthquake conditions in Japan show that relative densities have changed from 188 percent increase to 44 percent decrease. At present, there are no verified methods of seismic settlement analysis. However, there are current methods of analysis ranging from empirical to fully theoretical, which take into account a few to all of the major variables affecting seismically induced settlement behavior. This report reviews pertinent current knowledge and methodologies related to this subject. 69 references, 9 figures

  10. Seismic vulnerability assessment of chemical plants through probabilistic neural networks

    International Nuclear Information System (INIS)

    Aoki, T.; Ceravolo, R.; De Stefano, A.; Genovese, C.; Sabia, D.

    2002-01-01

    A chemical industrial plant represents a sensitive presence in a region and, in case of severe damage due to earthquake actions, its impact on social life and environment can be devastating. From the structural point of view, chemical plants count a number of recurrent elements, which are classifiable in a discrete set of typological families (towers, chimneys, cylindrical or spherical or prismatic tanks, pipes etc.). The final aim of this work is to outline a general procedure to be followed in order to assign a seismic vulnerability estimate to each element of the various typological families. In this paper, F.E. simulations allowed to create a training set, which has been used to train a probabilistic neural system. A sample application has concerned the seismic vulnerability of simple spherical tanks

  11. NRC systematic evaluation program: seismic review

    International Nuclear Information System (INIS)

    Levin, H.A.

    1980-01-01

    The NRC Systematic Evaluation Program is currently making an assessment of the seismic design safety of 11 older nuclear power plant facilities. The general review philosophy and review criteria relative to seismic input, structural response, and equipment functionability are presented, including the rationale for the development of these guidelines considering the significant evolution of seismic design criteria since these plants were originally licensed. Technical approaches thought more realistic in light of current knowledge are utilized. Initial findings for plants designed to early seismic design procedures suggest that with minor exceptions, these plants possess adequate seismic design margins when evaluated against the intent of current criteria. However, seismic qualification of electrical equipment has been identified as a subject which requires more in-depth evaluation

  12. Seismic vulnerability assessment of an Italian historical masonry dry dock

    OpenAIRE

    Marco Zucca; Pietro Giuseppe Crespi; Nicola Longarini

    2017-01-01

    The paper presents the seismic vulnerability analysis of the military dry dock built in 1861 inside the Messina’s harbor. The study appears very important not only for the relevance of the dry dock itself, but also for its social, military and symbolic role. As a first step, the historical documentation about the dry dock delivered by the Military Technical Office, in charge of its maintenance, was thoroughly examined. This activity was fundamental to understand the construction methods, the ...

  13. SEISMIC HAZARD ASSESSMENT OF SCHOOL BUILDINGS IN PENINSULAR MALAYSIA

    OpenAIRE

    Tan, K.T.; Razak, H. Abdul

    2015-01-01

    Peninsular Malaysia is located on the southern edge of the Eurasian Plate. However, it is close to a seismically active plate boundary, the inter-plate boundary between the Indo-Australian and Eurasian Plates. Occasionally, tremors can be felt throughout the region even when active faults are located several hundred kilometers away. Lessons learnt from past events, active earthquakes located far from the existing building can cause potential damage. Thus, fragility curves become an essential ...

  14. Application-driven ground motion prediction equation for seismic hazard assessments in non-cratonic moderate-seismicity areas

    Science.gov (United States)

    Bindi, D.; Cotton, F.; Kotha, S. R.; Bosse, C.; Stromeyer, D.; Grünthal, G.

    2017-09-01

    We present a ground motion prediction equation (GMPE) for probabilistic seismic hazard assessments (PSHA) in low-to-moderate seismicity areas, such as Germany. Starting from the NGA-West2 flat-file (Ancheta et al. in Earthquake Spectra 30:989-1005, 2014), we develop a model tailored to the hazard application in terms of data selection and implemented functional form. In light of such hazard application, the GMPE is derived for hypocentral distance (along with the Joyner-Boore one), selecting recordings at sites with vs30 ≥ 360 m/s, distances within 300 km, and magnitudes in the range 3 to 8 (being 7.4 the maximum magnitude for the PSHA in the target area). Moreover, the complexity of the considered functional form is reflecting the availability of information in the target area. The median predictions are compared with those from the NGA-West2 models and with one recent European model, using the Sammon's map constructed for different scenarios. Despite the simplification in the functional form, the assessed epistemic uncertainty in the GMPE median is of the order of those affecting the NGA-West2 models for the magnitude range of interest of the hazard application. On the other hand, the simplification of the functional form led to an increment of the apparent aleatory variability. In conclusion, the GMPE developed in this study is tailored to the needs for applications in low-to-moderate seismic areas and for short return periods (e.g., 475 years); its application in studies where the hazard is involving magnitudes above 7.4 and for long return periods is not advised.

  15. Seismic risk assessment in the Mexican Nuclear Center applying the Gumbel-I distribution

    International Nuclear Information System (INIS)

    Flores R, J.H.; Arguelles F, R.; Camacho L, M.E.; Urrutia F, J.

    1997-01-01

    A licensing requirement for the operation of nuclear facilities is the performance of different kinds of studies, one of which is seismic risk assessment. This study is useful for the validation of the seismic coefficient applied in the structural design of the facilities. Thus, for the construction of a pilot nuclear fuel plant at Mexico Nuclear Centre of the Instituto Nacional de Investigaciones Nucleares (ININ), was necessary to make such study. The seismicity data for the period between 1912 and 1990 were used and the extreme values Gumbel-I distribution was applied to them. With this, ground acceleration seismic risk maps for recurrence periods of 1, 25 and 50 years were drawn up, showing maximum values of 1.2, 4.25, and 5.0 gales, respectively. (Author)

  16. State of the Art in Input Ground Motions for Seismic Fragility and Risk Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Han; Choi, In Kil; Kim, Min Kyu [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The purpose of a Seismic Probabilistic Safety Analysis (SPSA) is to determine the probability distribution of core damage due to the potential effects of earthquakes. The SPSA is performed based on four steps, a seismic hazard analysis, a component fragility evaluation, a plant system and accident sequence analysis, and a consequence analysis. There are very different spectrum shapes in every ground motions. The structural response and the seismic load applied to equipment are greatly influenced by a spectral shape of the input ground motion. Therefore the input ground motion need to be determined under the same assumption in risk calculation. Several technic for the determination of input ground motions has developed and reviewed in this study. In this research, the methodologies of the determination of input ground motion for the seismic risk assessment are reviewed and discussed. It has developed to reduce the uncertainty in fragility curves and to remove the conservatism in risk values.

  17. A methodology for the quantitative risk assessment of major accidents triggered by seismic events

    International Nuclear Information System (INIS)

    Antonioni, Giacomo; Spadoni, Gigliola; Cozzani, Valerio

    2007-01-01

    A procedure for the quantitative risk assessment of accidents triggered by seismic events in industrial facilities was developed. The starting point of the procedure was the use of available historical data to assess the expected frequencies and the severity of seismic events. Available equipment-dependant failure probability models (vulnerability or fragility curves) were used to assess the damage probability of equipment items due to a seismic event. An analytic procedure was subsequently developed to identify, evaluate the credibility and finally assess the expected consequences of all the possible scenarios that may follow the seismic events. The procedure was implemented in a GIS-based software tool in order to manage the high number of event sequences that are likely to be generated in large industrial facilities. The developed methodology requires a limited amount of additional data with respect to those used in a conventional QRA, and yields with a limited effort a preliminary quantitative assessment of the contribution of the scenarios triggered by earthquakes to the individual and societal risk indexes. The application of the methodology to several case-studies evidenced that the scenarios initiated by seismic events may have a relevant influence on industrial risk, both raising the overall expected frequency of single scenarios and causing specific severe scenarios simultaneously involving several plant units

  18. Scenario for a Short-Term Probabilistic Seismic Hazard Assessment (PSHA in Chiayi, Taiwan

    Directory of Open Access Journals (Sweden)

    Chung-Han Chan

    2013-01-01

    Full Text Available Using seismic activity and the Meishan earthquake sequence that occurred from 1904 to 1906, a scenario for short-term probabilistic seismic hazards in the Chiayi region of Taiwan is assessed. The long-term earthquake occurrence rate in Taiwan was evaluated using a smoothing kernel. The highest seismicity rate was calculated around the Chiayi region. To consider earthquake interactions, the rate-and-state friction model was introduced to estimate the seismicity rate evolution due to the Coulomb stress change. As imparted by the 1904 Touliu earthquake, stress changes near the 1906 Meishan and Yangshuigang epicenters was higher than the magnitude of tidal triggering. With regard to the impact of the Meishan earthquake, the region close to the Yangshuigang earthquake epicenter had a +0.75 bar stress increase. The results indicated significant interaction between the three damage events. Considering the path and site effect using ground motion prediction equations, a probabilistic seismic hazard in the form of a hazard evolution and a hazard map was assessed. A significant elevation in hazards following the three earthquakes in the sequence was determined. The results illustrate a possible scenario for seismic hazards in the Chiayi region which may take place repeatly in the future. Such scenario provides essential information on earthquake preparation, devastation estimations, emergency sheltering, utility restoration, and structure reconstruction.

  19. Base Isolation for Seismic Retrofitting of a Multiple Building Structure: Design, Construction, and Assessment

    Directory of Open Access Journals (Sweden)

    Massimiliano Ferraioli

    2017-01-01

    Full Text Available The paper deals with the seismic retrofit of a multiple building structure belonging to the Hospital Centre of Avellino (Italy. At first, the paper presents the preliminary investigations, the in situ measurements and laboratory tests, and the seismic assessment of the existing fixed-base structures. Having studied different strategies, base isolation proved to be the more appropriate, also for the possibility offered by the geometry of the building to easily create an isolation interface at the ground level. The paper presents the design project, the construction process, and the details of the isolation intervention. Some specific issues of base isolation for seismic retrofitting of multiple building structures were lightened. Finally, the seismic assessment of the base-isolated building was carried out. The seismic response was evaluated through nonlinear time-history analysis, using the well-known Bouc-Wen model as the constitutive law of the isolation bearings. For reliable dynamic analyses, a suite of natural accelerograms compatible with acceleration spectra of Italian Code was first selected and then applied along both horizontal directions. The results were finally used to address some of the critical issues of the seismic response of the base-isolated multiple building structure: accidental torsional effects and potential poundings during strong earthquakes.

  20. Probabilistic seismic hazard assessments of Sabah, east Malaysia: accounting for local earthquake activity near Ranau

    Science.gov (United States)

    Khalil, Amin E.; Abir, Ismail A.; Ginsos, Hanteh; Abdel Hafiez, Hesham E.; Khan, Sohail

    2018-02-01

    Sabah state in eastern Malaysia, unlike most of the other Malaysian states, is characterized by common seismological activity; generally an earthquake of moderate magnitude is experienced at an interval of roughly every 20 years, originating mainly from two major sources, either a local source (e.g. Ranau and Lahad Dato) or a regional source (e.g. Kalimantan and South Philippines subductions). The seismicity map of Sabah shows the presence of two zones of distinctive seismicity, these zones are near Ranau (near Kota Kinabalu) and Lahad Datu in the southeast of Sabah. The seismicity record of Ranau begins in 1991, according to the international seismicity bulletins (e.g. United States Geological Survey and the International Seismological Center), and this short record is not sufficient for seismic source characterization. Fortunately, active Quaternary fault systems are delineated in the area. Henceforth, the seismicity of the area is thus determined as line sources referring to these faults. Two main fault systems are believed to be the source of such activities; namely, the Mensaban fault zone and the Crocker fault zone in addition to some other faults in their vicinity. Seismic hazard assessments became a very important and needed study for the extensive developing projects in Sabah especially with the presence of earthquake activities. Probabilistic seismic hazard assessments are adopted for the present work since it can provide the probability of various ground motion levels during expected from future large earthquakes. The output results are presented in terms of spectral acceleration curves and uniform hazard curves for periods of 500, 1000 and 2500 years. Since this is the first time that a complete hazard study has been done for the area, the output will be a base and standard for any future strategic plans in the area.

  1. Ophiolitic basement to the Great Valley forearc basin, California, from seismic and gravity data: Implications for crustal growth at the North American continental margin

    Science.gov (United States)

    Godfrey, N.J.; Beaudoin, B.C.; Klemperer, S.L.; Levander, A.; Luetgert, J.; Meltzer, A.; Mooney, W.; Tréhu, A.

    1997-01-01

    The nature of the Great Valley basement, whether oceanic or continental, has long been a source of controversy. A velocity model (derived from a 200-km-long east-west reflection-refraction profile collected south of the Mendocino triple junction, northern California, in 1993), further constrained by density and magnetic models, reveals an ophiolite underlying the Great Valley (Great Valley ophiolite), which in turn is underlain by a westward extension of lower-density continental crust (Sierran affinity material). We used an integrated modeling philosophy, first modeling the seismic-refraction data to obtain a final velocity model, and then modeling the long-wavelength features of the gravity data to obtain a final density model that is constrained in the upper crust by our velocity model. The crustal section of Great Valley ophiolite is 7-8 km thick, and the Great Valley ophiolite relict oceanic Moho is at 11-16 km depth. The Great Valley ophiolite does not extend west beneath the Coast Ranges, but only as far as the western margin of the Great Valley, where the 5-7-km-thick Great Valley ophiolite mantle section dips west into the present-day mantle. There are 16-18 km of lower-density Sierran affinity material beneath the Great Valley ophiolite mantle section, such that a second, deeper, "present-day" continental Moho is at about 34 km depth. At mid-crustal depths, the boundary between the eastern extent of the Great Valley ophiolite and the western extent of Sierran affinity material is a near-vertical velocity and density discontinuity about 80 km east of the western margin of the Great Valley. Our model has important implications for crustal growth at the North American continental margin. We suggest that a thick ophiolite sequence was obducted onto continental material, probably during the Jurassic Nevadan orogeny, so that the Great Valley basement is oceanic crust above oceanic mantle vertically stacked above continental crust and continental mantle.

  2. Simplified Assessment of R3 Nominal Assurance Degree to Seismic Action of the Existing Masonry Dwellings

    Directory of Open Access Journals (Sweden)

    Teodor Broşteanu

    2008-01-01

    Full Text Available This paper refers to the assessment of the performance level of a building for a given seismic hazard level. Building performance level describes the expected seismic performance given by the computation of R3 Nominal Assurance Degree to Seismic Action of the Existing Masonry Dwellings and Monumental Buildings according to the Romanian Norm P100:1992 [1], modified on 1996 with the chapters 11 and 12, until the Part 3 of P100-1:2006 [2], will be performed for the Assessment and Strengthening Structural Design of the Seismic Vulnerable, Existing Buildings, in the frame of SR EN 1998-1:2004 EC8 [3]. The framing of damages into the potential risk degrees has a social and economic impact. Assessment and retrofitting of the existing buildings have represented a huge engineering challenge as a distinct problem versus a new building design. The performance level of a vulnerable existing building shows us the expected seismic performance level due to the classified damages, the pattern of cracks, the interruption of function, the economic losses and the needed interventions, all in function of the importance class of building on next life span of use. On recommends the computation of R (R3 Nominal Assurance Degree to Seismic Action of the Vulnerable Dwellings for the assessing and strengthening design, in comparison to both norms because of the bearing conventional seismic load computed by [1], will result less than the value which will be computed by the Part 3 of P100-1:2006, i.e. the norm P100:1992 is more severe. In the case of the breakable fracture probability of the existing structural masonry members, one recommends a bigger value of ? – reduction factor unless the given values by [1] for a new structure with a high ductility, especially for the deflections calibration on the same limit state.

  3. FSI-based Overflow Assessment of the Seismically-Isolated SFP with Fuel Racks

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Gil Y.; Park, Hyun T.; Chang, Soo-Hyuk [Korea Maintenance Co., Seoul (Korea, Republic of); Lee, Sang-Hoon [KEPCO E-C, Yongin (Korea, Republic of)

    2014-10-15

    To date, effectiveness of the seismic isolation systems for reducing seismic force effectively has been well demonstrated. In this context, practical application of the technology in nuclear engineering fields has become an important issue more and more. This is because fluid motion can be rather amplified due to the increased relative displacement between the base and superstructures by a long-period shift. Therefore, overflow assessment and prediction of the seismically-isolated SFP have to be conducted in design phase. For performing sloshing-induced overflow of the seismically-isolated SFP, a fluid-structure interaction(FSI) approach making a two-way coupling process between structural and fluid solvers is herein employed. In this study, fuel racks inside the SFP are included in FSI modeling to investigate effect of fuel-cell assemblies on SFP overflow. Accordingly, three different assembly sets of fuel cells are assumed to be inserted in fuel racks. In addition, floor acceleration time-histories produced from three different amplitudes of peak ground acceleration (PGA) are applied to the SFP base to investigate load effect on liquid overflow. An approach for the liquid overflow assessment of the seismically-isolated nuclear SFP with fuel storage racks based on FSI analysis was addressed. From the results of the identified cases, the following conclusions are drawn: (i) FSI technique can be effectively used to assess the seismically-isolated SFP overflow, (ii) In a conservative way, the isolated SFP without fuel racks can be used to assess its sloshing-induced overflow under earthquake since effect of fuel-cell assemblies on the SFP overflow is not significant, (iii) for given same conditions (e.g., constant design free surface, same fuel-cell assembly) except seismic loading, the higher PGA is, the more liquid overflow increases.

  4. 3D modeling of stratigraphic units and simulation of seismic facies in the Lion gulf margin; Modelisation 3D des unites stratigraphiques et simulation des facies sismiques dans la marge du golfe du Lion

    Energy Technology Data Exchange (ETDEWEB)

    Chihi, H.

    1997-05-12

    This work aims at providing a contribution to the studies carried out on reservoir characterization by use of seismic data. The study mainly consisted in the use of geostatistical methods in order to model the geometry of stratigraphic units of the Golfe du Lion margin and to simulate the seismic facies from high resolution seismic data. We propose, for the geometric modelling, a methodology based on the estimation of the surfaces and calculation afterwards of the thicknesses, if the modelling of the depth is possible. On the other hand the method consists in estimating the thickness variable directly and in deducing the boundary surfaces afterwards. In order to simulate the distribution of seismic facies within the units of the western domain, we used the truncated Gaussian method. The used approach gave a satisfactory results, when the seismic facies present slightly dipping reflectors with respect to the reference level. Otherwise the method reaches its limits because of the problems of definition of a reference level which allows to follow the clino-forms. In spite of these difficulties, this simulation allows us to estimate the distribution of seismic facies within the units and then to deduce their probable extension. (author) 150 refs.

  5. Seismic hazard and risk assessment for large Romanian dams situated in the Moldavian Platform

    Science.gov (United States)

    Moldovan, Iren-Adelina; Popescu, Emilia; Otilia Placinta, Anica; Petruta Constantin, Angela; Toma Danila, Dragos; Borleanu, Felix; Emilian Toader, Victorin; Moldoveanu, Traian

    2016-04-01

    Besides periodical technical inspections, the monitoring and the surveillance of dams' related structures and infrastructures, there are some more seismic specific requirements towards dams' safety. The most important one is the seismic risk assessment that can be accomplished by rating the dams into seismic risk classes using the theory of Bureau and Ballentine (2002), and Bureau (2003), taking into account the maximum expected peak ground motions at the dams site - values obtained using probabilistic hazard assessment approaches (Moldovan et al., 2008), the structures vulnerability and the downstream risk characteristics (human, economical, historic and cultural heritage, etc) in the areas that might be flooded in the case of a dam failure. Probabilistic seismic hazard (PSH), vulnerability and risk studies for dams situated in the Moldavian Platform, starting from Izvorul Muntelui Dam, down on Bistrita and following on Siret River and theirs affluent will be realized. The most vulnerable dams will be studied in detail and flooding maps will be drawn to find the most exposed downstream localities both for risk assessment studies and warnings. GIS maps that clearly indicate areas that are potentially flooded are enough for these studies, thus giving information on the number of inhabitants and goods that may be destroyed. Geospatial servers included topography is sufficient to achieve them, all other further studies are not necessary for downstream risk assessment. The results will consist of local and regional seismic information, dams specific characteristics and locations, seismic hazard maps and risk classes, for all dams sites (for more than 30 dams), inundation maps (for the most vulnerable dams from the region) and possible affected localities. The studies realized in this paper have as final goal to provide the local emergency services with warnings of a potential dam failure and ensuing flood as a result of an large earthquake occurrence, allowing further

  6. Assessing mediation using marginal structural models in the presence of confounding and moderation

    OpenAIRE

    Coffman, Donna L.; Zhong, Wei

    2012-01-01

    This paper presents marginal structural models (MSMs) with inverse propensity weighting (IPW) for assessing mediation. Generally, individuals are not randomly assigned to levels of the mediator. Therefore, confounders of the mediator and outcome may exist that limit causal inferences, a goal of mediation analysis. Either regression adjustment or IPW can be used to take confounding into account, but IPW has several advantages. Regression adjustment of even one confounder of the mediator and ou...

  7. A national seismographic network for assessing seismic hazards

    International Nuclear Information System (INIS)

    Masse, R.P.; Murphy, A.J.

    1989-01-01

    To access the seismic hazard of a region and to establish the design and construction criteria for critical facilities such as nuclear power plants, detailed information is required on the frequency of occurrence, geographical distribution, magnitude, and energy spectra of earthquakes. Also important is information on the frequency-dependent attenuation of seismic waves. This information can all be obtained from data recorded by networks of seismograph stations. A new seismograph network for the US which takes advantage of advances in technology is currently under development. This network is the US National Seismograph Network (USNSN). The USNSN is a cooperative effort between the National Earthquake Information Center (NEIC) of the US Geological survey and the Nuclear Regulatory Commission. The USNSN will be installed and operated by the NEIC. The network will consist of approximately 150 seismograph stations distributed across the lower 48 states and across Alaska, Hawaii, Puerto Rico, and the Virgin Islands. The design goal for the network is the on-scale recording by at least five well-distributed stations of any event of magnitude 2.5 or larger in the continental US, Hawaii, and Puerto Rico, and of any event of magnitude 3.5 or larger in Alaska. The rapid access to all USNSN data will be provided by the NEIC. This will be accomplished both via a dial-up capability to the event waveform data base and by satellite transmission in a broadcast mode. All earthquake data will also be distributed on compact disk with read only memory (CD-ROM) to all institutions having an interest in the seismic data

  8. Seismic damage assessment for high-rise buildings

    Science.gov (United States)

    Scholl, Roger E.

    1980-01-01

    The problem considered in this project, conducted by URS/John A. Blume & Associates, Engineers (URS/Blume), for the U.S. Geological Survey, is the identification, evaluation, and correlation of ground-motion and structural parameters in order to improve procedures for predicting dollar losses for high-rise structures damaged by earthquakes. Ground-motion data bases, analytical techniques, and known motion-damage relationships already developed for high-rise buildings and for other classes of structures will be refined and extended so that reliable quantitative seismic risk evaluations can be made.

  9. AECB workshop on seismic hazard assessment in Southern Ontario. Program, list of participants and abstracts

    International Nuclear Information System (INIS)

    1995-01-01

    The purpose of the workshop was to review available geological and seismological data which could affect earthquake occurrence in southern Ontario and to develop a consensus on approaches that should be adopted for characterization of seismic hazard. The workshop was structured in technical sessions to focus presentations and discussions on four technical issues relevant to seismic hazard in southern Ontario, as follows: (1) The importance of geological and geophysical observations for the determination of seismic sources, (2) Methods and approaches which may be adopted for determining seismic sources based on integrated interpretations of geological and seismological information, (3) Methods and data which should be used for characterizing the seismicity parameters of seismic sources, and (4) Methods for assessment of vibratory ground motion hazard. This document presents a copy of the workshop program, the list of participants and extended abstracts received from speakers. It was distributed to the participants prior to the workshop. The abstracts were intended to provide advance information and to afford some basis for meaningful discussion and exchange of information

  10. AECB workshop on seismic hazard assessment in Southern Ontario. Program, list of participants and abstracts

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    The purpose of the workshop was to review available geological and seismological data which could affect earthquake occurrence in southern Ontario and to develop a consensus on approaches that should be adopted for characterization of seismic hazard. The workshop was structured in technical sessions to focus presentations and discussions on four technical issues relevant to seismic hazard in southern Ontario, as follows: (1) The importance of geological and geophysical observations for the determination of seismic sources, (2) Methods and approaches which may be adopted for determining seismic sources based on integrated interpretations of geological and seismological information, (3) Methods and data which should be used for characterizing the seismicity parameters of seismic sources, and (4) Methods for assessment of vibratory ground motion hazard. This document presents a copy of the workshop program, the list of participants and extended abstracts received from speakers. It was distributed to the participants prior to the workshop. The abstracts were intended to provide advance information and to afford some basis for meaningful discussion and exchange of information.

  11. An Assessment of the Seismicity of the Bursa Region from a Temporary Seismic Network

    Science.gov (United States)

    Gok, Elcin; Polat, Orhan

    2012-04-01

    A temporary earthquake station network of 11 seismological recorders was operated in the Bursa region, south of the Marmara Sea in the northwest of Turkey, which is located at the southern strand of the North Anatolian Fault Zone (NAFZ). We located 384 earthquakes out of a total of 582 recorded events that span the study area between 28.50-30.00°E longitudes and 39.75-40.75°N latitudes. The depth of most events was found to be less than 29 km, and the magnitude interval ranges were between 0.3 ≤ ML ≤ 5.4, with RMS less than or equal to 0.2. Seismic activities were concentrated southeast of Uludag Mountain (UM), in the Kestel-Igdir area and along the Gemlik Fault (GF). In the study, we computed 10 focal mechanisms from temporary and permanents networks. The predominant feature of the computed focal mechanisms is the relatively widespread near horizontal northwest-southeast (NW-SE) T-axis orientation. These fault planes have been used to obtain the orientation and shape factor (R, magnitude stress ratio) of the principal stress tensors (σ1, σ2, σ3). The resulting stress tensors reveal σ1 closer to the vertical (oriented NE-SW) and σ2, σ3 horizontal with R = 0.5. These results confirm that Bursa and its vicinity could be defined by an extensional regime showing a primarily normal to oblique-slip motion character. It differs from what might be expected from the stress tensor inversion for the NAFZ. Different fault patterns related to structural heterogeneity from the north to the south in the study area caused a change in the stress regime from strike-slip to normal faulting.

  12. Mapping basin-wide subaquatic slope failure susceptibility as a tool to assess regional seismic and tsunami hazards

    Science.gov (United States)

    Strasser, Michael; Hilbe, Michael; Anselmetti, Flavio S.

    2010-05-01

    occurred. Comparison of reconstructed critical stability conditions with the known distribution of landslide deposits reveals minimum and maximum threshold conditions for slopes that failed or remained stable, respectively. The resulting correlations reveal good agreements and suggest that the slope stability model generally succeeds in reproducing past events. The basin-wide mapping of subaquatic slope failure susceptibility through time thus can also be considered as a promising paleoseismologic tool that allows quantification of past earthquake ground shaking intensities. Furthermore, it can be used to assess the present-day slope failure susceptibility allowing for identification of location and estimation of size of future, potentially tsunamigenic subaquatic landslides. The new approach presented in our comprehensive lake study and resulting conceptual ideas can be vital to improve our understanding of larger marine slope instabilities and related seismic and oceanic geohazards along formerly glaciated ocean margins and closed basins worldwide.

  13. Setting the Stage for Harmonized Risk Assessment by Seismic Hazard Harmonization in Europe (SHARE)

    Science.gov (United States)

    Woessner, Jochen; Giardini, Domenico; SHARE Consortium

    2010-05-01

    Probabilistic seismic hazard assessment (PSHA) is arguably one of the most useful products that seismology can offer to society. PSHA characterizes the best available knowledge on the seismic hazard of a study area, ideally taking into account all sources of uncertainty. Results form the baseline for informed decision making, such as building codes or insurance rates and provide essential input to each risk assessment application. Several large scale national and international projects have recently been launched aimed at improving and harmonizing PSHA standards around the globe. SHARE (www.share-eu.org) is the European Commission funded project in the Framework Programme 7 (FP-7) that will create an updated, living seismic hazard model for the Euro-Mediterranean region. SHARE is a regional component of the Global Earthquake Model (GEM, www.globalquakemodel.org), a public/private partnership initiated and approved by the Global Science Forum of the OECD-GSF. GEM aims to be the uniform, independent and open access standard to calculate and communicate earthquake hazard and risk worldwide. SHARE itself will deliver measurable progress in all steps leading to a harmonized assessment of seismic hazard - in the definition of engineering requirements, in the collection of input data, in procedures for hazard assessment, and in engineering applications. SHARE scientists will create a unified framework and computational infrastructure for seismic hazard assessment and produce an integrated European probabilistic seismic hazard assessment (PSHA) model and specific scenario based modeling tools. The results will deliver long-lasting structural impact in areas of societal and economic relevance, they will serve as reference for the Eurocode 8 (EC8) application, and will provide homogeneous input for the correct seismic safety assessment for critical industry, such as the energy infrastructures and the re-insurance sector. SHARE will cover the whole European territory, the

  14. Assessment of seismic wave effects on soil-structure interaction

    International Nuclear Information System (INIS)

    Bernreuter, D.L.

    1977-01-01

    One of the most common hypotheses made for soil-structure interaction analyses is that the earthquake input motion is identical at all points beneath the structure. Several papers have recently shown that this assumption may be overly conservative and that the effect of wave passage is extremely important. These studies typically employ a relatively simple model, namely, the basemat is represented by a rectangular rigid foundation resting on top of the soil and connected to the soil by a continuously distributed set of soil springs. The seismic input is applied at the base of the soil springs and is assumed to be traveling at a constant wave velocity across the site. It ispossible to improve on the soil/structure model by use of finite element methods; however, little is known about how to model the input seismic energy and typically a simple travelling wave is used. In this paper, the author examines the available data to determine: (i) the appropriate wave velocity to use, and (ii) if the currently availble analytic models are adequate. (Auth.)

  15. Seismic performance assessment of three masonry churches through FE simulations

    Science.gov (United States)

    Milani, Gabriele; Shehu, Rafael; Valente, Marco

    2017-07-01

    The paper presents some seismic analyses on three masonry churches located in Emilia-Romagna (Italy), recently stricken by a devastating earthquake sequence from 20th to 29th May 2012. These churches have a similar geometrical configuration, consisting of three naves, a central colonnade and a simple apse. Limit analyses are conducted on the most important macro-elements of the structure and a full investigation of the churches is carried out by means of the commercial FE Code SAP2000, in both linear and non-linear ranges. Two accelerograms are considered: one is defined in accordance with Italian code response spectrum and the other is based on a natural record of the 29th May earthquake. For both scenarios, the seismic behaviour of the churches is analysed in detail and some vulnerability considerations are drawn. A remarkable consistency is found between limit analyses of macro-elements and response spectrum analyses, whilst some discrepancies can be noted for non-linear dynamic analyses. The results put in evidence the insufficient strength of the apses for shear actions, the columns of the naves for bending moments, the façade for overturning and the triumphal arch for the formation of an in-plane four hinges mechanism.

  16. Assessment of seismic wave effects on soil-structure interaction

    International Nuclear Information System (INIS)

    Bernreuter, D.L.

    1977-03-01

    It is normally assumed in the seismic analysis of structures that the free-field motion which is used as input is the same for all points on a given level beneath the foundation mat. This represents a simplification, as not all particles of soil describe the same motion simultaneously. As the foundation mat of the structure is rigid in the horizontal direction, it will tend to average the ground motion. Abandoning the assumption of the uniformity of the input motion may lead to a reduction of the translational motion which a foundation mat will experience, as the displacement components will cancel each other to a certain extent. This is of considerable interest for the design of nuclear power plants which are very stiff, large structures. To investigate these effects, the extremely complex phenomenon of the passage of a seismic wave has to be simplified considerably. It is the purpose of this paper to determine if wave passage effects can be determined from the simplified analyses currently used

  17. Market modeling for assessment of demand side programs using the marginal cost

    International Nuclear Information System (INIS)

    Papastamatiou, Panagiotis; Psarras, John

    2000-01-01

    Demand side management is nowadays considered as a functional step in the energy planning process. The criteria proposed for the assessment of the demand side programs (DSPs) are usually based on the balance between the marginal supply cost and the mean DSP cost. These criteria could not support the allotting of the invested capital to incentives for the consumers and advertising. This paper presents a methodology to support the utility planning at this point with more reliability. It proposes the expansion of the assessment criteria with the use of the marginal cost of the DSP. For the calculation of the DSP marginal cost, a dynamic model is developed and it is used for the simulation of the penetration of a DS Program. Using the 'least-cost' criterion as the decision rule for the simulation, the planner has a distribution of the available investment capital throughout the whole planning period. The use of the 'most-value' criterion supports the separation of the invested capital between incentives for the consumers and supportive expenses, e.g. advertising, marketing cost, etc. (Author)

  18. Safety Margin Assessment (SM2A): Stimulation for Further Development of BEPU Approaches?

    International Nuclear Information System (INIS)

    Zimmermann, Martin A.

    2013-01-01

    During recent years, many nuclear power plants underwent significant modifications, e.g. power up-rating. While compliance with all the deterministic acceptance criteria must be shown during the licensing process, the larger core inventory and the facts that the plant response might get closer to the limits after a power up-rate, suggest an increase of the core damage frequency (CDF) and other possible risk indicators. Hence, a framework to quantitatively assess a change in plant safety margin becomes very desirable. The Committee on the Safety of Nuclear Installations (CSNI) mandated the Safety Margin Action Plan expert group (SMAP) to develop a framework for the assessment of such changes to safety margin. This framework combines PSA and the analytical techniques developed in BEPU. CSNI then mandated the SM2A expert group to especially explore the practicability of the SMAP framework. This pilot study was completed end of 2010. An increase of the (conditional) probability of exceedance for a surrogate acceptance limit (PCT) indicating core damage was successfully evaluated for the selected sequences from several initiating event trees, and it was found that only a restricted number of sequences need to be analyzed. Based on the insights gained from this study, areas of methodology improvement have been identified and related proposals for further R and D work will be discussed. (authors)

  19. A Pareto analysis approach to assess relevant marginal CO{sub 2} footprint for petroleum products

    Energy Technology Data Exchange (ETDEWEB)

    Tehrani, Nejad M. Alireza, E-mail: alireza.tehraninejad@gmail.com

    2015-07-15

    Recently, linear programing (LP) models have been extended to track the marginal CO{sub 2} intensity of automotive fuels at the refinery gate. The obtained CO{sub 2} data are recommended for policy making because they capture the economic and environmental tensions as well as the processing effects related to oil products. However, they are proven to be extremely sensitive to small perturbations and therefore useless in practice. In this paper, we first investigate the theoretical reasons of this drawback. Then, we develop a multiple objective LP framework to assess relevant marginal CO{sub 2} footprints that preserve both defensibility and stability at a satisfactory level of acceptance. A case study illustrates this new methodology. - Highlights: • Refining LP models have limitations to provide useful marginal CO{sub 2} footprints. • A multi objective optimization framework is developed to assess relevant CO{sub 2} data. • Within a European Refinig industry, diesel is more CO{sub 2} intensive than gasoline.

  20. Marginal Generation Technology in the Chinese Power Market towards 2030 Based on Consequential Life Cycle Assessment

    DEFF Research Database (Denmark)

    Zhao, Guangling; Guerrero, Josep M.; Pei, Yingying

    2016-01-01

    Electricity consumption is often the hotspot of life cycle assessment (LCA) of products, industrial activities, or services. The objective of this paper is to provide a consistent, scientific, region-specific electricity-supply-based inventory of electricity generation technology for national...... and regional power grids. Marginal electricity generation technology is pivotal in assessing impacts related to additional consumption of electricity. China covers a large geographical area with regional supply grids; these are arguably equally or less integrated. Meanwhile, it is also a country with internal...

  1. Application of Gumbel I and Monte Carlo methods to assess seismic hazard in and around Pakistan

    Science.gov (United States)

    Rehman, Khaista; Burton, Paul W.; Weatherill, Graeme A.

    2018-05-01

    A proper assessment of seismic hazard is of considerable importance in order to achieve suitable building construction criteria. This paper presents probabilistic seismic hazard assessment in and around Pakistan (23° N-39° N; 59° E-80° E) in terms of peak ground acceleration (PGA). Ground motion is calculated in terms of PGA for a return period of 475 years using a seismogenic-free zone method of Gumbel's first asymptotic distribution of extreme values and Monte Carlo simulation. Appropriate attenuation relations of universal and local types have been used in this study. The results show that for many parts of Pakistan, the expected seismic hazard is relatively comparable with the level specified in the existing PGA maps.

  2. Seismic risk assessment of architectural heritages in Gyeongju considering local site effects

    Science.gov (United States)

    Park, H.-J.; Kim, D.-S.; Kim, D.-M.

    2013-02-01

    A seismic risk assessment is conducted for cultural heritage sites in Gyeongju, the capital of Korea's ancient Silla Kingdom. Gyeongju, home to UNESCO World Heritage sites, contains remarkable artifacts of Korean Buddhist art. An extensive geotechnical survey including a series of in situ tests is presented, providing pertinent soil profiles for site response analyses on thirty cultural heritage sites. After the shear wave velocity profiles and dynamic material properties were obtained, site response analyses were carried out at each historical site and the amplification characteristics, site period, and response spectrum of the site were determined for the earthquake levels of 2400 yr and 1000 yr return periods based on the Korean seismic hazard map. Response spectrum and corresponding site coefficients obtained from site response analyses considering geologic conditions differ significantly from the current Korean seismic code. This study confirms the importance of site-specific ground response analyses considering local geological conditions. Results are given in the form of the spatial distribution of bedrock depth, site period, and site amplification coefficients, which are particularly valuable in the context of a seismic vulnerability study. This study presents the potential amplification of hazard maps and provides primary data on the seismic risk assessment of each cultural heritage.

  3. A transparent and data-driven global tectonic regionalization model for seismic hazard assessment

    Science.gov (United States)

    Chen, Yen-Shin; Weatherill, Graeme; Pagani, Marco; Cotton, Fabrice

    2018-05-01

    A key concept that is common to many assumptions inherent within seismic hazard assessment is that of tectonic similarity. This recognizes that certain regions of the globe may display similar geophysical characteristics, such as in the attenuation of seismic waves, the magnitude scaling properties of seismogenic sources or the seismic coupling of the lithosphere. Previous attempts at tectonic regionalization, particularly within a seismic hazard assessment context, have often been based on expert judgements; in most of these cases, the process for delineating tectonic regions is neither reproducible nor consistent from location to location. In this work, the regionalization process is implemented in a scheme that is reproducible, comprehensible from a geophysical rationale, and revisable when new relevant data are published. A spatial classification-scheme is developed based on fuzzy logic, enabling the quantification of concepts that are approximate rather than precise. Using the proposed methodology, we obtain a transparent and data-driven global tectonic regionalization model for seismic hazard applications as well as the subjective probabilities (e.g. degree of being active/degree of being cratonic) that indicate the degree to which a site belongs in a tectonic category.

  4. Component fragility analysis methodology for seismic risk assessment projects. Proven PSA safety document processing and assessment procedures

    International Nuclear Information System (INIS)

    Kolar, Ladislav

    2013-03-01

    The seismic risk task assessment task should be structured as follows: (i) Define all reactor unit building structures, components and equipment involved in the creation of an initiating event (IE) induced by an seismic event or contributing to the reliability of reactor unit response to an IE; (ii) construct and estimate of the fragility curves for the building and component groups sub (i); (iii) determine the HCLPF for each group of buildings, components or equipment; (iv) determine the nuclear source's seismic resistance (SME) as the minimum HCLPF from the group of equipment in the risk-dominant scenarios; (v) define the risk-limiting group of components, equipment and building structures to the SME value; (vi) based on the fragility levels, identify component groups for which a more detailed fragility analysis is needed; and (vii) recommend groups of equipment or building structures that should be taken into account with respect to the seismic risk, i.e. such groups of equipment or building structures as exhibit a low seismic resistance (HCLPF) and, at the same time, are involved to a significant extent in the reactor unit's seismic risk (are present in the dominant risk scenarios). (P.A.)

  5. Assessment of faulting and seismic hazards at Yucca Mountain

    International Nuclear Information System (INIS)

    King, J.L.; Frazier, G.A.; Grant, T.A.

    1989-01-01

    Yucca Mountain is being evaluated for the nation's first high-level nuclear-waste repository. Local faults appear to be capable of moderate earthquakes at recurrence intervals of tens of thousands of years. The major issues identified for the preclosure phase (<100 yrs) are the location and seismic design of surface facilities for handling incoming waste. It is planned to address surface fault rupture by locating facilities where no discernible recent (<100,000 yrs) faulting has occurred and to base the ground motion design on hypothetical earthquakes, postulated on nearby faults, that represent 10,000 yrs of average cumulative displacement. The major tectonic issues identified for the postclosure phase (10,000 yrs) are volcanism (not addressed here) and potential changes to the hydrologic system resulting from a local faulting event which could trigger potential thermal, mechanical, and chemical interactions with the ground water. Extensive studies are planned for resolving these issues. 33 refs., 3 figs

  6. A new view for the geodynamics of Ecuador: Implication in seismogenic source definition and seismic hazard assessment

    Science.gov (United States)

    Yepes, Hugo; Audin, Laurence; Alvarado, Alexandra; Beauval, Céline; Aguilar, Jorge; Font, Yvonne; Cotton, Fabrice

    2016-05-01

    A new view of Ecuador's complex geodynamics has been developed in the course of modeling seismic source zones for probabilistic seismic hazard analysis. This study focuses on two aspects of the plates' interaction at a continental scale: (a) age-related differences in rheology between Farallon and Nazca plates—marked by the Grijalva rifted margin and its inland projection—as they subduct underneath central Ecuador, and (b) the rapidly changing convergence obliquity resulting from the convex shape of the South American northwestern continental margin. Both conditions satisfactorily explain several characteristics of the observed seismicity and of the interseismic coupling. Intermediate-depth seismicity reveals a severe flexure in the Farallon slab as it dips and contorts at depth, originating the El Puyo seismic cluster. The two slabs position and geometry below continental Ecuador also correlate with surface expressions observable in the local and regional geology and tectonics. The interseismic coupling is weak and shallow south of the Grijalva rifted margin and increases northward, with a heterogeneous pattern locally associated to the Carnegie ridge subduction. High convergence obliquity is responsible for the North Andean Block northeastward movement along localized fault systems. The Cosanga and Pallatanga fault segments of the North Andean Block-South American boundary concentrate most of the seismic moment release in continental Ecuador. Other inner block faults located along the western border of the inter-Andean Depression also show a high rate of moderate-size earthquake production. Finally, a total of 19 seismic source zones were modeled in accordance with the proposed geodynamic and neotectonic scheme.

  7. Crust and upper-mantle structure of Wanganui Basin and southern Hikurangi margin, North Island, New Zealand as revealed by active source seismic data

    Science.gov (United States)

    Tozer, B.; Stern, T. A.; Lamb, S. L.; Henrys, S. A.

    2017-11-01

    Wide-angle reflection and refraction data recorded during the Seismic Array HiKurangi Experiment (SAHKE) are used to constrain the crustal P-wave velocity (Vp) structure along two profiles spanning the length and width of Wanganui Basin, located landwards of the southern Hikurangi subduction margin, New Zealand. These models provide high-resolution constraints on the structure and crustal thickness of the overlying Australian and subducted Pacific plates and plate interface geometry. Wide-angle reflections are modelled to show that the subducted oceanic Pacific plate crust is anomalously thick (∼10 km) below southern North Island and is overlain by a ∼1.5-4.0 km thick, low Vp (4.8-5.4 km s-1) layer, interpreted as a channel of sedimentary material, that persists landwards at least as far as Kapiti Island. Distinct near vertical reflections from onshore shots identify a ∼4 km high mound of low-velocity sedimentary material that appears to underplate the overlying Australian plate crust and is likely to contribute to local rock uplift along the Axial ranges. The overriding Australian plate Moho beneath Wanganui Basin is imaged as deepening southwards and reaches a depth of at least 36.4 km. The Moho shape approximately mirrors the thickening of the basin sediments, suggestive of crustal downwarping. However, the observed crustal thickness variation is insufficient to explain the large negative Bouguer gravity anomaly (-160 mGal) centred over the basin. Partial serpentinization within the upper mantle with a concomitant density decrease is one possible way of reconciling this anomaly.

  8. A probabilistic seismic risk assessment procedure for nuclear power plants: (II) Application

    Science.gov (United States)

    Huang, Y.-N.; Whittaker, A.S.; Luco, N.

    2011-01-01

    This paper presents the procedures and results of intensity- and time-based seismic risk assessments of a sample nuclear power plant (NPP) to demonstrate the risk-assessment methodology proposed in its companion paper. The intensity-based assessments include three sets of sensitivity studies to identify the impact of the following factors on the seismic vulnerability of the sample NPP, namely: (1) the description of fragility curves for primary and secondary components of NPPs, (2) the number of simulations of NPP response required for risk assessment, and (3) the correlation in responses between NPP components. The time-based assessment is performed as a series of intensity-based assessments. The studies illustrate the utility of the response-based fragility curves and the inclusion of the correlation in the responses of NPP components directly in the risk computation. ?? 2011 Published by Elsevier B.V.

  9. Safety assessment for the passive system of the nuclear power plants (NPPs) using safety margin estimation

    International Nuclear Information System (INIS)

    Woo, Tae-Ho; Lee, Un-Chul

    2010-01-01

    The probabilistic safety assessment (PSA) for gas-cooled nuclear power plants has been investigated where the operational data are deficient, because there is not any commercial gas-cooled nuclear power plant. Therefore, it is necessary to use the statistical data for the basic event constructions. Several estimations for the safety margin are introduced for the quantification of the failure frequency in the basic event, which is made by the concept of the impact and affordability. Trend of probability of failure (TPF) and fuzzy converter (FC) are introduced using the safety margin, which shows the simplified and easy configurations for the event characteristics. The mass flow rate in the natural circulation is studied for the modeling. The potential energy in the gravity, the temperature and pressure in the heat conduction, and the heat transfer rate in the internal stored energy are also investigated. The values in the probability set are compared with those of the fuzzy set modeling. Non-linearity of the safety margin is expressed by the fuzziness of the membership function. This artificial intelligence analysis of the fuzzy set could enhance the reliability of the system comparing to the probabilistic analysis.

  10. A comparison of analytical approaches for the assessment of seismic displacements of geosynthetically reinforced geostructures

    DEFF Research Database (Denmark)

    Tzavara, I.; Tsompanakis, Y.; Zania, Varvara

    2012-01-01

    Aim of the current study is to assess the dynamic response of reinforced soil structures and the potential of the geosynthetics to prevent the seismic induced instabilities taking advantage of their reinforcing effect. For this purpose, representative models of reinforced soil slopes are developed...

  11. Seismic hazard assessment for Central, North and Northwest Europe: GSHAP Region 3

    Czech Academy of Sciences Publication Activity Database

    Grunthal, G.; Bosse, Ch.; Camelbeeck, T.; de Crook, T.; Gariel, J. C.; Gregersen, S.; Guterch, B.; Halldorsson, P.; Labák, P.; Lindholm, C.; Lenhardt, W.; Mantyniemi, P.; Mayer-Rosa, D.; Musson, R. M. W.; Schenk, Vladimír; Schenková, Zdeňka; Slejko, D.; Verbeiren, R.; Wahlstrom, R.; Zabukovec, B.; Ziros, T.

    1999-01-01

    Roč. 42, č. 6 (1999), s. 999-1011 ISSN 0365-2556 R&D Projects: GA AV ČR Global Seismic Hazard Assessment Program (GSHAP) - project of the UN International Decade of Natural Disaster Reduction and International Litosphere Program. Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  12. Probabilistic tsunami hazard assessment considering time-lag of seismic event on Nankai trough

    International Nuclear Information System (INIS)

    Sugino, Hideharu; Sakagami, Masaharu; Ebisawa, Katsumi; Korenaga, Mariko

    2011-01-01

    In the area in front of Nankai trough, tsunami wave height may increase if tsunamis attacking from some wave sources overlap because of time-lag of seismic event on Nankai trough. To evaluation tsunami risk of the important facilities located in front of Nankai trough, we proposed the probabilistic tsunami hazard assessment considering uncertainty on time-lag of seismic event on Nankai trough and we evaluated the influence that the time-lag gave to tsunami hazard at the some representative points. (author)

  13. Assessing the cost-effectiveness of seismic risk reduction options in oil industry

    International Nuclear Information System (INIS)

    Nasserasadi, K.; Ghafory-Ashtiany, M.

    2007-01-01

    An integrated probabilistic methodology for cost-efficiency estimation of different sort of seismic risk management measures are introduced by adding Cost Benefit Analysis (CBA) module to an integrated seismic risk assessment model. An oil refinery in Iran has been selected for case study and cost-efficiency of software and hardware mitigation measures are evaluated. The results have shown that: (1) software mitigation measures have more benefit than hardware ones, (2) considering indirect loss in CBA lead to more benefit-cost ratio and (3) although increase of discount ratio decreases the benefit-cost ratio, the arrangement of mitigation measures from benefit-cost viewpoint are constant. (authors)

  14. Life-cycle cost assessment of seismically base-isolated structures in nuclear power plants

    International Nuclear Information System (INIS)

    Wang, Hao; Weng, Dagen; Lu, Xilin; Lu, Liang

    2013-01-01

    Highlights: • The life-cycle cost of seismic base-isolated nuclear power plants is modeled. • The change law of life-cycle cost with seismic fortification intensity is studied. • The initial cost of laminated lead rubber bearings can be expressed as the function of volume. • The initial cost of a damper can be expressed as the function of its maximum displacement and tonnage. • The use of base-isolation can greatly reduce the expected damage cost, which leads to the reduction of the life-cycle cost. -- Abstract: Evaluation of seismically base-isolated structural life-cycle cost is the key problem in performance based seismic design. A method is being introduced to address the life-cycle cost of base-isolated reinforced concrete structures in nuclear power plants. Each composition of life-cycle cost is analyzed including the initial construction cost, the isolators cost and the excepted damage cost over life-cycle of the structure. The concept of seismic intensity is being used to estimate the expected damage cost, greatly simplifying the calculation. Moreover, French Cruas nuclear power plant is employed as an example to assess its life-cycle cost, compared to the cost of non-isolated plant at the same time. The results show that the proposed method is efficient and the expected damage cost is enormously reduced because of the application of isolators, which leads to the reduction of the life-cycle cost of nuclear power plants

  15. A new probabilistic seismic hazard assessment for greater Tokyo

    Science.gov (United States)

    Stein, R.S.; Toda, S.; Parsons, T.; Grunewald, E.; Blong, R.; Sparks, S.; Shah, H.; Kennedy, J.

    2006-01-01

    Tokyo and its outlying cities are home to one-quarter of Japan's 127 million people. Highly destructive earthquakes struck the capital in 1703, 1855 and 1923, the last of which took 105 000 lives. Fuelled by greater Tokyo's rich seismological record, but challenged by its magnificent complexity, our joint Japanese-US group carried out a new study of the capital's earthquake hazards. We used the prehistoric record of great earthquakes preserved by uplifted marine terraces and tsunami deposits (17 M???8 shocks in the past 7000 years), a newly digitized dataset of historical shaking (10 000 observations in the past 400 years), the dense modern seismic network (300 000 earthquakes in the past 30 years), and Japan's GeoNet array (150 GPS vectors in the past 10 years) to reinterpret the tectonic structure, identify active faults and their slip rates and estimate their earthquake frequency. We propose that a dislodged fragment of the Pacific plate is jammed between the Pacific, Philippine Sea and Eurasian plates beneath the Kanto plain on which Tokyo sits. We suggest that the Kanto fragment controls much of Tokyo's seismic behaviour for large earthquakes, including the damaging 1855 M???7.3 Ansei-Edo shock. On the basis of the frequency of earthquakes beneath greater Tokyo, events with magnitude and location similar to the M??? 7.3 Ansei-Edo event have a ca 20% likelihood in an average 30 year period. In contrast, our renewal (time-dependent) probability for the great M??? 7.9 plate boundary shocks such as struck in 1923 and 1703 is 0.5% for the next 30 years, with a time-averaged 30 year probability of ca 10%. The resulting net likelihood for severe shaking (ca 0.9g peak ground acceleration (PGA)) in Tokyo, Kawasaki and Yokohama for the next 30 years is ca 30%. The long historical record in Kanto also affords a rare opportunity to calculate the probability of shaking in an alternative manner exclusively from intensity observations. This approach permits robust estimates

  16. Seismic hazard for the Savannah River Site: A comparative evaluation of the EPRI and LLNL assessments

    International Nuclear Information System (INIS)

    Wingo, H.E.

    1992-01-01

    This report was conducted to: (1) develop an understanding of causes for the vast differences between the two comprehensive studies, and (2) using a methodology consistent with the reconciled methods employed in the two studies, develop a single seismic hazard for the Savannah River Site suitable for use in seismic probabilistic risk assessments with emphasis on the K Reactor. Results are presented for a rock site which is a typical because detailed evaluations of soil characteristics at the K Reactor are still in progress that account for the effects of a soil stablizing grouting program. However when the soils analysis is completed, the effects of soils can be included with this analysis with the addition of a single factor that will decrease slightly the seismic hazard for a rock site

  17. Assessment of unhealthy days of urban marginal inhabitants and effective factors in Mashhad, Iran

    Directory of Open Access Journals (Sweden)

    Maliheh Ziaee

    2016-01-01

    Full Text Available Background: The concept of the quality of life (HRQOL related to health and its determinants contain aspects of quality of life that clearly affect people’s physical or mental health. One of the newest ways to assess the health and also the quality of life-related to health is the self-assessed health of the individual. The aim of the present study was assessment of unhealthy days, self-reported health status, and its influencing factors on residents of the marginalpart of Mashhad, Iran. Methods: In the current cross-sectional study, 580 citizens of the marginal regions and slum areas of Mashhad city were enrolled through cluster sampling method using governmental health care services divisions. The Persian version of the questionnaire CDC HRQOL-4 was used to measure the unhealthy days. Data was analyzed using SPSS, version 11.5, running ANOVA, chi-square, and t-tests. P-value of less than 0.05 was considered as statistically significant. Results: In the present study, 359 persons (61% were women and the mean age of participants was 32.6±11.51 years. The means of unhealthy days, physically unhealthy days, mentally unhealthy days, and days with dysfunction were found to be 7.2, 2.8, 4.1, and 1.7 days, respectively. The unhealthiest days (physical and mental were seen in unemployed people and the best to excellent health days were seen in housewives. Conclusion: Unhealthy days and days with dysfunction were reported higher in slum inhabitants, especially female, low literacy, and housewife participants. Providing the education and employment facilities for people who live in marginal city areas might decrease the unhealthy days.Keywords: Unhealthy days; Health; Urban Marginal Inhabitants; Mashhad

  18. Intra-operative Cerenkov Imaging for Guiding Breast Cancer Surgery and Assessing Tumor Margins

    Science.gov (United States)

    2014-03-01

    application, 13/492,606 • One travel award to attend WMIC in Dublin (2012) • One class taught as lead instructor ( Mechatronics system ) • Three classes...paraffin- embedded tissue: five years on. Cytometry. 1989;10:229–241. 15. Meng LJ, Fu G, Roy EJ, Suppe B, Chen CT. An ultrahigh resolution SPECT system for...residual cancer. This grant aims to develop a system to assess tumor margins during surgery, with the eventual goal of reducing re-excision surgery

  19. Seismic performance assessment of base-isolated safety-related nuclear structures

    Science.gov (United States)

    Huang, Y.-N.; Whittaker, A.S.; Luco, N.

    2010-01-01

    Seismic or base isolation is a proven technology for reducing the effects of earthquake shaking on buildings, bridges and infrastructure. The benefit of base isolation has been presented in terms of reduced accelerations and drifts on superstructure components but never quantified in terms of either a percentage reduction in seismic loss (or percentage increase in safety) or the probability of an unacceptable performance. Herein, we quantify the benefits of base isolation in terms of increased safety (or smaller loss) by comparing the safety of a sample conventional and base-isolated nuclear power plant (NPP) located in the Eastern U.S. Scenario- and time-based assessments are performed using a new methodology. Three base isolation systems are considered, namely, (1) Friction Pendulum??? bearings, (2) lead-rubber bearings and (3) low-damping rubber bearings together with linear viscous dampers. Unacceptable performance is defined by the failure of key secondary systems because these systems represent much of the investment in a new build power plant and ensure the safe operation of the plant. For the scenario-based assessments, the probability of unacceptable performance is computed for an earthquake with a magnitude of 5.3 at a distance 7.5 km from the plant. For the time-based assessments, the annual frequency of unacceptable performance is computed considering all potential earthquakes that may occur. For both assessments, the implementation of base isolation reduces the probability of unacceptable performance by approximately four orders of magnitude for the same NPP superstructure and secondary systems. The increase in NPP construction cost associated with the installation of seismic isolators can be offset by substantially reducing the required seismic strength of secondary components and systems and potentially eliminating the need to seismically qualify many secondary components and systems. ?? 2010 John Wiley & Sons, Ltd.

  20. Probabilistic seismic hazard assessment of the historical peninsula of Istanbul

    Directory of Open Access Journals (Sweden)

    G. Ç. Ince

    2012-11-01

    Full Text Available In order to design buildings that are resistant to earthquakes, first it is necessary to determine the parameters of ground motion. In this study, the earthquake seismic hazard analysis of the Old City Districts of Istanbul (Fatih and Eminonu was probabilistically defined. For the analysis, the study zone was divided into 307 cells of 250 × 250 m using geographical information systems, and these cells were used in the mapping of all the data obtained. Then, for a building lifetime of 50 yr, the acceleration parameters of earthquake ground motions, peak ground acceleration, peak ground velocity, and spectral acceleration values of 0.2 s and 1 s were obtained at the bedrock level according to 10% and 40% exceedances. Additionally, in order to produce the artificial acceleration-time records of the ground movement in accordance with the NEHRP acceleration spectrum, the TARSCHTS computer simulation program was utilized. The results of the analysis showed that for the 10% probability of exceedance, the peak bedrock acceleration values ranged from 0.30 g to 0.40 g, and for the 40% exceedance probability the acceleration values ranged from 0.22 g to 0.17 g. The Ss 10% exceedance probability, calculated according to the spectral acceleration parameter, ranged from 0.67 g to 0.85 g and the spectral acceleration parameter S1 varied between 0.22 g–0.28 g. The Ss 40% exceedance probability, calculated according to the spectral acceleration parameter, ranged from 0.46 g to 0.38 g and the spectral acceleration parameter S1 varied from 0.12 g to 0.14 g.

  1. Seismic Hazard Assessment and Uncertainties Treatment: Discussion on the current French regulation, practices and open issues

    International Nuclear Information System (INIS)

    Berge-Thierry, Catherine

    2014-01-01

    Taking into account the seismic risk in the context of nuclear safety in France is guided by the Fundamental Safety Rule (RFS2001-01) for the assessment of seismic hazard, and by the Guide ASN/2/01 for the design rules of civil engineering structures. These two references have been updated respectively in 2001 and 2006 and validated by the Nuclear Safety Authority. The French approach is anchored on a deterministic approach. We propose to recall the principles of the methodology recommended by the RFS 2001-01, and to illustrate the advantages and limitations highlighted in recent years. Indeed, this regulatory framework is used both in the design stage and for safety reassessment of all nuclear facilities, power reactors and experimental laboratories and factories. We focus on: (i) key parameters of the approach, and their level of knowledge, (ii) key steps and principles that lead to a non-homogeneous approach between various geographic sites, depending on the seismic activity and / or knowledge, (iii) on physical phenomena (such as the geometric extension of the seismic source, the complexity of earthquake rupture on the fault plane) that are not taken into account, or for which (2D and 3D site effects, and non-linear soil behavior under strong motions), the RFS 2001-01 approach does not provide any guidance, (iv) consideration of epistemic and random uncertainties. We discuss also the probabilistic approaches widely implemented both in France as recently to establish the seismic zoning (reference for the regulation of conventional building and classified installations for the environment), used worldwide and strongly supported by the international Atomic Energy Agency references (safety guides and guidelines). The Tohoku earthquake that occurred in Japan on March 11, 2011, triggering the tsunami that itself caused the nuclear accident at Fukushima Daiichi site has resulted in the realization in France of the Complementary Safety Studies as a request of the

  2. Seismic Hazard and risk assessment for Romania -Bulgaria cross-border region

    Science.gov (United States)

    Simeonova, Stela; Solakov, Dimcho; Alexandrova, Irena; Vaseva, Elena; Trifonova, Petya; Raykova, Plamena

    2016-04-01

    Among the many kinds of natural and man-made disasters, earthquakes dominate with regard to their social and economical impact on the urban environment. Global seismic hazard and vulnerability to earthquakes are steadily increasing as urbanization and development occupy more areas that are prone to effects of strong earthquakes. The assessment of the seismic hazard and risk is particularly important, because it provides valuable information for seismic safety and disaster mitigation, and it supports decision making for the benefit of society. Romania and Bulgaria, situated in the Balkan Region as a part of the Alpine-Himalayan seismic belt, are characterized by high seismicity, and are exposed to a high seismic risk. Over the centuries, both countries have experienced strong earthquakes. The cross-border region encompassing the northern Bulgaria and southern Romania is a territory prone to effects of strong earthquakes. The area is significantly affected by earthquakes occurred in both countries, on the one hand the events generated by the Vrancea intermediate-depth seismic source in Romania, and on the other hand by the crustal seismicity originated in the seismic sources: Shabla (SHB), Dulovo, Gorna Orjahovitza (GO) in Bulgaria. The Vrancea seismogenic zone of Romania is a very peculiar seismic source, often described as unique in the world, and it represents a major concern for most of the northern part of Bulgaria as well. In the present study the seismic hazard for Romania-Bulgaria cross-border region on the basis of integrated basic geo-datasets is assessed. The hazard results are obtained by applying two alternative approaches - probabilistic and deterministic. The MSK64 intensity (MSK64 scale is practically equal to the new EMS98) is used as output parameter for the hazard maps. We prefer to use here the macroseismic intensity instead of PGA, because it is directly related to the degree of damages and, moreover, the epicentral intensity is the original

  3. Life Cycle Assessment of Bioenergy from Lignocellulosic Crops Cultivated on Marginal Land in Europe

    Science.gov (United States)

    Rettenmaier, Nils; Schmidt, Tobias; Gärtner, Sven; Reinhardt, Guido

    2017-04-01

    Population growth and changing diets due to economic development lead to an additional demand for land for food and feed production. Slowly but surely turning into a mass market, also the cultivation of non-food biomass crops for fibre (bio-based products) and fuel (biofuels and bioenergy) is increasingly contributing to the pressure on global agricultural land. As a consequence, the already prevailing competition for land might even intensify over the next decades. Against this background, the possibilities of shifting the cultivation of non-food biomass crops to so-called 'marginal lands' are investigated. The EC-funded project 'Sustainable exploitation of biomass for bioenergy from marginal lands in Europe' (SEEMLA) aims at the establishment of suitable innovative land-use strategies for a sustainable production of bioenergy from lignocellulosic crops on marginal lands while improving general ecosystem services. For a complete understanding of the environmental benefits and drawbacks of the envisioned cultivation of bioenergy crops on marginal land, life cycle assessments (LCA) have proven to be a suitable and valuable tool. Thus, embedded into a comprehensive sustainability assessment, a screening LCA is carried out for the entire life cycles of the bioenergy carriers researched in SEEMLA. Investigated systems, on the one hand, include the specific field trials carried out by the SEEMLA partners in Ukraine, Greece and Germany. On the other hand, generic scenarios are investigated in order to derive reliable general statements on the environmental impacts of bioenergy from marginal lands in Europe. Investigated crops include woody and herbaceous species such as black locust, poplar, pine, willow and Miscanthus. Conversion technologies cover the use in a domestic or a district heating plant, power plant, CHP as well as the production of Fischer-Tropsch diesel (FT diesel) and lignocellulosic ethanol. Environmental impacts are compared to conventional reference

  4. Correlation of breast tissue histology and optical signatures to improve margin assessment techniques

    Science.gov (United States)

    Kennedy, Stephanie; Caldwell, Matthew; Bydlon, Torre; Mulvey, Christine; Mueller, Jenna; Wilke, Lee; Barry, William; Ramanujam, Nimmi; Geradts, Joseph

    2016-06-01

    Optical spectroscopy is sensitive to morphological composition and has potential applications in intraoperative margin assessment. Here, we evaluate ex vivo breast tissue and corresponding quantified hematoxylin & eosin images to correlate optical scattering signatures to tissue composition stratified by patient characteristics. Adipose sites (213) were characterized by their cell area and density. All other benign and malignant sites (181) were quantified using a grid method to determine composition. The relationships between mean reduced scattering coefficient (), and % adipose, % collagen, % glands, adipocyte cell area, and adipocyte density were investigated. These relationships were further stratified by age, menopausal status, body mass index (BMI), and breast density. We identified a positive correlation between and % collagen and a negative correlation between and age and BMI. Increased collagen corresponded to increased variability. In postmenopausal women, was similar regardless of fibroglandular content. Contributions from collagen and glands to were independent and equivalent in benign sites; glands showed a stronger positive correlation than collagen to in malignant sites. Our data suggest that scattering could differentiate highly scattering malignant from benign tissues in postmenopausal women. The relationship between scattering and tissue composition will support improved scattering models and technologies to enhance intraoperative optical margin assessment.

  5. Re-assessment of seismic loads in conjunction with periodic safety review

    International Nuclear Information System (INIS)

    Jonczyk, Josef

    2002-01-01

    The objective of this paper is the fundamental consideration of a safeguard-aim-oriented approach for use in the re-assessment of seismic events with regard to the periodic safety review (PSR) of nuclear power plants (NPP). The re-assessment aspects of site-specific design earthquakes (DEQ), specially the procedure for seismic hazard analysis, will not, however, be considered in detail here. The proposed assessment concept clearly presents a general approach for safety assessments. The approach is based on a successive screening review of components that are considered sufficiently earthquake-resistant. In this respect, the principle of maximum practical application of the design documentation has been considered in the re-assessment process. On the other hand, the safeguard-aim-oriented evaluation will also be applied with regard to whether the requirements of the safety regulations are fulfilled with respect to the safety goals. The review in conjunction with PSR does not, however, attempt to perform this under all technical aspects. Moreover, it is possible to make extensive use of experimental knowledge and engineering judgement with regard to the structural capacity behaviour in case of a seismic event. Compared with design procedures, however, this proposed approach differs from the one applied in licensing procedures, in which such assessment freedom will not usually be exhausted. (author)

  6. Probabilistic Assessment of Structural Seismic Damage for Buildings in Mid-America

    International Nuclear Information System (INIS)

    Bai, Jong-Wha; Hueste, Mary Beth D.; Gardoni, Paolo

    2008-01-01

    This paper provides an approach to conduct a probabilistic assessment of structural damage due to seismic events with an application to typical building structures in Mid-America. The developed methodology includes modified damage state classifications based on the ATC-13 and ATC-38 damage states and the ATC-38 database of building damage. Damage factors are assigned to each damage state to quantify structural damage as a percentage of structural replacement cost. To account for the inherent uncertainties, these factors are expressed as random variables with a Beta distribution. A set of fragility curves, quantifying the structural vulnerability of a building, is mapped onto the developed methodology to determine the expected structural damage. The total structural damage factor for a given seismic intensity is then calculated using a probabilistic approach. Prediction and confidence bands are also constructed to account for the prevailing uncertainties. The expected seismic structural damage is assessed for a typical building structure in the Mid-America region using the developed methodology. The developed methodology provides a transparent procedure, where the structural damage factors can be updated as additional seismic damage data becomes available

  7. A Multimode Adaptive Pushover Procedure for Seismic Assessment of Integral Bridges

    Directory of Open Access Journals (Sweden)

    Ehsan Mohtashami

    2013-01-01

    Full Text Available This paper presents a new adaptive pushover procedure to account for the effect of higher modes in order to accurately estimate the seismic response of bridges. The effect of higher modes is considered by introducing a minimum value for the total effective modal mass. The proposed method employs enough number of modes to ensure that the defined total effective modal mass participates in all increments of the pushover loading. An adaptive demand curve is also developed for assessment of the seismic demand. The efficiency and robustness of the proposed method are demonstrated by conducting a parametric study. The analysis includes 18 four-span integral bridges with various heights of piers. The inelastic response history analysis is employed as reference solution in this study. Numerical results indicate excellent accuracy of the proposed method in assessment of the seismic response. For most bridges investigated in this study, the difference between the estimated response of the proposed method and the inelastic response history analysis is less than 25% for displacements and 10% for internal forces. This indicates a very good accuracy compared to available pushover procedures in the literature. The proposed method is therefore recommended to be applied to the seismic performance evaluation of integral bridges for engineering applications.

  8. Seismic assessment of existing RC buildings under alternative ground motion ensembles compatible to EC8 and NTC 2008

    NARCIS (Netherlands)

    Tanganelli, Marco; Viti, Stefania; Mariani, V.; Pianigiani, Maria

    2017-01-01

    This work investigates the effects of the choice of different ensembles of ground motions on the seismic assessment of existing RC buildings through nonlinear dynamic analysis. Nowadays indeed, all the main International Seismic Codes provide a soil classification which is based on the shear wave

  9. Assessing soil quality and potential productivity - a basic approach to define and assess the marginality of land

    Science.gov (United States)

    Repmann, Frank; Gerwin, Werner; Freese, Dirk

    2017-04-01

    An ever growing demand for energy and the widely proposed switch from fossil fuels to more sustainable energy sources puts the cultivation and use of bioenergy plants into focus. However, bioenergy production on regular and fertile agricultural soils might conflict with the worldwide growing demand for food. To mitigate or omit this potential conflict, the use of low quality or marginal land for cultivation of bioenergy plants becomes favorable. Against this background the definition and assessment of land marginality and, respectively, the evaluation whether and to which extent specific areas are marginal and thus convenient for sustainable bioenergy production, becomes highly relevant. Within the framework of the EU funded Horizon 2020 project SEEMLA, we attempted to asses land marginality of designated test sites in the Ukraine, Greece and Germany by direct field survey. For that purpose, soil and site properties were investigated and evaluated by applying the Muencheberg Soil Quality Rating (SQR) method, developed at the Leibniz Centre for Agricultural Landscape Research (ZALF). The method deploys a comprehensive set of biogeophysical and chemical indicators to describe and finally evaluate the quality of the soil and site by a score ranging from 1 to 100 points. Field survey data were supported by additional laboratory tests on a representative set of soil samples. Practical field work and analysis of field and lab data from the investigated sites proved the applicability of the SQR method within the SEEMLA context. The SQR indices calculated from the field and lab data ranged from 2 to Greece and Germany, which differed considerably in respect to their characteristics. Correlating the site quality index to yield data reflecting yield estimations for common bioenergy plants such as willow (Salix sp.), black locust (Robinia pseudoacacia) and poplar (Populus sp.) cultivated at the respective test sites, revealed that SQR might additionally reflect the potential

  10. Economic assessment of Operational Energy reduction options in a house using Marginal Benefit and Marginal Cost: A case in Bangi, Malaysia

    International Nuclear Information System (INIS)

    Wan Rahmah Mohd Zaki; Abdul Hadi Nawawi; Sabarinah Sh Ahmad

    2010-01-01

    Energy Efficient (EE) appliances such as Compact Fluorescent Light (CFL) bulbs and Renewable Energy (RE), namely solar Photovoltaic (PV) can help to reduce Operational Energy (OE) in a house. In addition, a house should also incorporate Passive Architecture (PA) design strategies which in the hot and humid tropical climate, mean avoiding direct heat gain, encouraging natural cross ventilation and optimising the abundant daylight. Nevertheless, reducing OE must also mean economic gain to households to encourage their participation. Common economic gauges such as Return on Investment, Payback Period, Cost Benefit Analysis, Life Cycle Assessment and Life Cycle Cost are not suitable to validate OE options in households. These economic gauges approach economic assessment as an end-result on the cost side of the product and may result for good intention to be shelved, primarily because EE equipment and RE have high capital cost compared with the alternatives. On the other hand, reducing OE in houses is actually a continual progression from the status quo and there is always a marginal gain in doing so. The challenge is to know how much is the marginal benefit against the marginal cost of investing in EE and RE. In Economics, the ratio of Marginal Cost (MC) and Marginal Benefits (MB) measure additional benefits of every additional costs of investment at a specific level of production and consumption; and Economists suggests that effective gain and loss should be compared to the status quo, i.e., Relative Position (RP). The Economics theories of MC, MB and RP are being adapted to measure the progression of reducing OE. The living/dining area in two types of houses: with and without PA design strategies are simulated to use conventional incandescent light bulbs and CFL as well as solar PV in lieu of the mains electricity supply. The power requirement for artificial lighting in every case is translated into monetary value and the ratio of MB against MC for each case shows

  11. Seismic hazard assessment of the Province of Murcia (SE Spain): analysis of source contribution to hazard

    Science.gov (United States)

    García-Mayordomo, J.; Gaspar-Escribano, J. M.; Benito, B.

    2007-10-01

    A probabilistic seismic hazard assessment of the Province of Murcia in terms of peak ground acceleration (PGA) and spectral accelerations [SA( T)] is presented in this paper. In contrast to most of the previous studies in the region, which were performed for PGA making use of intensity-to-PGA relationships, hazard is here calculated in terms of magnitude and using European spectral ground-motion models. Moreover, we have considered the most important faults in the region as specific seismic sources, and also comprehensively reviewed the earthquake catalogue. Hazard calculations are performed following the Probabilistic Seismic Hazard Assessment (PSHA) methodology using a logic tree, which accounts for three different seismic source zonings and three different ground-motion models. Hazard maps in terms of PGA and SA(0.1, 0.2, 0.5, 1.0 and 2.0 s) and coefficient of variation (COV) for the 475-year return period are shown. Subsequent analysis is focused on three sites of the province, namely, the cities of Murcia, Lorca and Cartagena, which are important industrial and tourism centres. Results at these sites have been analysed to evaluate the influence of the different input options. The most important factor affecting the results is the choice of the attenuation relationship, whereas the influence of the selected seismic source zonings appears strongly site dependant. Finally, we have performed an analysis of source contribution to hazard at each of these cities to provide preliminary guidance in devising specific risk scenarios. We have found that local source zones control the hazard for PGA and SA( T ≤ 1.0 s), although contribution from specific fault sources and long-distance north Algerian sources becomes significant from SA(0.5 s) onwards.

  12. Performance-based seismic assessment of vulnerability of dam using time history analysis

    Directory of Open Access Journals (Sweden)

    Elmrabet Oumnia

    2018-01-01

    Full Text Available The current performance-based seismic assessment procedure can be computationally intensive as it requires many time history analyses (THA each requiring time intensive post-processing of results. Time history analysis is a part of structural analysis and is the calculation of the response of a structure to any earthquake. It is one of the main processes of structural design in regions where earthquakes are prevalent. The objective of this study is to evaluate the seismic performance of embankment dam located on the Oued RHISS in the Province of AL HOCEIMA using the THA method. To monitor structural behavior, the seismic vulnerability of structure is evaluated under real earthquake records with considering the soil-structure-fluide interaction. In this study, a simple assistant program is developed for implementing earthquake analyses of structure with ANSYS, ground acceleration–time history data are used for seismic analysis and dynamic numerical simulations were conducted to study and identify the total response of the soil-structure system.

  13. Seismic ground motion and hazard assessment of the Greater Accra Metropolitan Area, southeastern Ghana

    International Nuclear Information System (INIS)

    Amponsah, P.E.; Banoeng-Yakubo, B.K.; Asiedu, D.; Vaccari, F.; Panza, G.F.

    2008-08-01

    The seismic ground motion of the Greater Accra Metropolitan area has been computed and the hazard zones assessed using a deterministic hybrid approach based on the modal summation and finite difference methods. The seismic ground motion along four profiles located in the Greater Accra Metropolitan Area has been modelled using the 1939 earthquake of magnitude 6.5(M L ) as the scenario earthquake. Synthetic seismic waveforms from which parameters for engineering design such as peak ground acceleration, velocity and spectral amplifications have been produced along the geological cross sections. From the seismograms computed, the seismic hazard of the metropolis, expressed in terms of peak ground acceleration and peak ground velocity have been estimated. The peak ground acceleration estimated in the study ranges from 0.14 - 0.57 g and the peak ground velocity from 9.2 - 37.1cms -1 . The presence of low velocity sediments gave rise to high peak values and amplifications. The maximum peak ground accelerations estimated are located in areas with low velocity formations such as colluvium, continental and marine deposits. Areas in the metropolis underlain by unconsolidated sediments have been classified as the maximum damage potential zone and those underlain by highly consolidated geological materials are classified as low damage potential zone. The results of the numerical simulation have been extended to all areas in the metropolis with similar geological formation. (author)

  14. Seismic Hazard and Risk Assessments for Beijing-Tianjin-Tangshan, China, Area

    Science.gov (United States)

    Xie, Furen; Wang, Zhenming; Liu, Jingwei

    2011-03-01

    Seismic hazard and risk in the Beijing-Tianjin-Tangshan, China, area were estimated from 500-year intensity observations. First, we digitized the intensity observations (maps) using ArcGIS with a cell size of 0.1 × 0.1°. Second, we performed a statistical analysis on the digitized intensity data, determined an average b value (0.39), and derived the intensity-frequency relationship (hazard curve) for each cell. Finally, based on a Poisson model for earthquake occurrence, we calculated seismic risk in terms of a probability of I ≥ 7, 8, or 9 in 50 years. We also calculated the corresponding 10 percent probability of exceedance of these intensities in 50 years. The advantages of assessing seismic hazard and risk from intensity records are that (1) fewer assumptions (i.e., earthquake source and ground motion attenuation) are made, and (2) site-effect is included. Our study shows that the area has high seismic hazard and risk. Our study also suggests that current design peak ground acceleration or intensity for the area may not be adequate.

  15. Review of seismic probabilistic risk assessment and the use of sensitivity analysis

    International Nuclear Information System (INIS)

    Shiu, K.K.; Reed, J.W.; McCann, M.W. Jr.

    1985-01-01

    This paper presents results of sensitivity reviews performed to address a range of questions which arise in the context of seismic probabilistic risk assessment (PRA). In a seismic PRA, sensitivity evaluations can be divided into three areas: hazard, fragility, and system modeling. As a part of the review of standard boiling water reactor seismic PRA which was performed by General Electric (GE), a reassessment of the plant damage states frequency and a detailed sensitivity analysis were conducted at Brookhaven National Laboratory. The rationale for such an undertaking is that in this case: (1) the standard plant may be sited anywhere in the eastern US (i.e., in regions with safety shutdown earthquake (SSE) values equal to or less than 0.3g peak ground acceleration), (2) it may have equipment whose fragility values could vary over a wide range; and (3) there are variations in system designs outside the original defined scope. Seismic event trees and fault trees were developed to model the different system and plant accident sequences. Hazard curves which represent various sites on the east coast were obtained; alternate structure and equipment fragility data were postulated. Various combinations of hazard and fragility data were analyzed. In addition, system modeling was perturbed to examine the impact upon the final results. Orders of magnitude variation were observed in the plant damage state frequency among the different cases. 7 references, 3 figures, 2 tables

  16. A preliminary regional assessment of earthquake-induced landslide susceptibility for Vrancea Seismic Region

    Science.gov (United States)

    Micu, Mihai; Balteanu, Dan; Ionescu, Constantin; Havenith, Hans; Radulian, Mircea; van Westen, Cees; Damen, Michiel; Jurchescu, Marta

    2015-04-01

    In seismically-active regions, earthquakes may trigger landslides enhancing the short-to-long term slope denudation and sediment delivery and conditioning the general landscape evolution. Co-seismic slope failures present in general a low frequency - high magnitude pattern which should be addressed accordingly by landslide hazard assessment, with respect to the generally more frequent precipitation-triggered landslides. The Vrancea Seismic Region, corresponding to the curvature sector of the Eastern Romanian Carpathians, represents the most active sub-crustal (focal depth > 50 km) earthquake province of Europe. It represents the main seismic energy source throughout Romania with significant transboundary effects recorded as far as Ukraine and Bulgaria. During the last 300 years, the region featured 14 earthquakes with M>7, among which seven events with magnitude above 7.5 and three between 7.7 and 7.9. Apart from the direct damages, the Vrancea earthquakes are also responsible for causing numerous other geohazards, such as ground fracturing, groundwater level disturbances and possible deep-seated landslide occurrences (rock slumps, rock-block slides, rock falls, rock avalanches). The older deep-seated landslides (assumed to have been) triggered by earthquakes usually affect the entire slope profile. They often formed landslide dams strongly influencing the river morphology and representing potential threats (through flash-floods) in case of lake outburst. Despite the large potential of this research issue, the correlation between the region's seismotectonic context and landslide predisposing factors has not yet been entirely understood. Presently, there is a lack of information provided by the geohazards databases of Vrancea that does not allow us to outline the seismic influence on the triggering of slope failures in this region. We only know that the morphology of numerous large, deep-seated and dormant landslides (which can possibly be reactivated in future

  17. Complete removal of a breast mass by US-guided mammotome biopsy: histologic assessment by marginal sampling

    International Nuclear Information System (INIS)

    Kim, Youn Jeong; Choi, Hye Young; Moon, Byung In; Lee, Shi Nae

    2005-01-01

    The aim of this study was to assess whether the complete removal of a breast mass using ultrasound (US) guided mammotome biopsy was successful using a marginal biopsy after insuring the total visual excision of the breast mass on US images. The relationship of complete breast mass removal, and the hematoma, mass size and shape were also evaluated. A US guided mammotome biopsy was performed in a total of 136 cases in 133 patients, with marginal biopsies also added when the complete removal of breast mass had been identified by sonography. The results of the marginal biopsies were serially dividing into three groups, as follows: group I were the cases in the initial 6 months, group II after the initial 6 months and group III having undergone two marginal biopsies. The marginal biopsies were performed in four directions around the probe, with 'marginal positivity' defined as the same histopathological findings to that of the main mass in at least one direction. A statistical analysis was also used to evaluate between the marginal positivity and the hematoma, mass size and shape. The marginal positivities of groups I, II and III were 48.8, 29.4 and 45.5%, respectively. The marginal positivity of those with a lobular shaped mass was significantly higher (ρ = 0.0121) than those with round or oval shaped masses (61.5 vs 33.7 vs 50%), but showed no statistical relationship with hematoma size of the lesions. Although the lesions were removed by US using a US-guided mammotome biopsy, many residual lesions were still histologically present in the marginal samplings, especially in the lobular shaped masse

  18. Seismic analysis for the ALMR

    International Nuclear Information System (INIS)

    Tajirian, F.F.

    1992-01-01

    The Advanced Liquid Metal Reactor (ALMR) design uses seismic isolation as a cost effective approach for simplifying seismic design of the reactor module, and for enhancing margins to handle beyond design basis earthquakes (BDBE). A comprehensive seismic analysis plan has been developed to confirm the adequacy of the design and to support regulatory licensing activities. In this plan state-of-the-art computer programs are used to evaluate the system response of the ALMR. Several factors that affect seismic response will be investigated. These include variability in the input earthquake mechanism, soil-structure interaction effects, and nonlinear response of the isolators. This paper reviews the type of analyses that are planned, and discuses the approach that will be used for validating the specific features of computer programs that are required in the analysis of isolated structures. To date, different linear and nonlinear seismic analyses have been completed. The results of recently completed linear analyses have been summarized elsewhere. The findings of three-dimensional seismic nonlinear analyses are presented in this paper. These analyses were performed to evaluate the effect of changes of isolator horizontal stiffness with horizontal displacement on overall response, to develop an approach for representing BDBE events with return periods exceeding 10,000 years, and to assess margins in the design for BDBEs. From the results of these analyses and bearing test data, it can be concluded that a properly designed and constructed seismic isolation system can accommodate displacements several times the design safe shutdown earthquake (SSE) for the ALMR. (author)

  19. Fracture mechanics characteristics and associated safety margins for integrity assessment; Bruchmechanische Kennwerte und zugeordnete Sicherheitsfaktoren bei Integritaetsanalysen

    Energy Technology Data Exchange (ETDEWEB)

    Roos, E.; Schuler, X.; Stumpfrock, L.; Silcher, H. [Stuttgart Univ. (DE). Materialpruefungsanstalt (MPA)

    2008-07-01

    Within the integrity assessment of components and structural members of plants safety margins have to be applied, whose magnitude depend on several factors. Important factors influencing the magnitude of the safety margins are as for instance: Material behaviour (ductile / brittle behaviour), the event to be considered (local deformation / fracture), possible consequences of failure (human health, environmental damage, economic consequences) and many others. One important factor also is the fact, how precisely and reliably the appropriate material characteristics can be determined and how precisely and reliably the components behaviour can be predicted and assessed by means of this material characteristic. In contemporary safety assessment procedures by means of fracture mechanics evaluation tools (e.g. [1]) a concept of partial safety margins is proposed for application. The basic idea with this procedure is that only those sources of uncertainty have to be considered, which are relevant or may be relevant for the structure to be considered. For this purpose each source of possible uncertainty has to be quantified individually, finally only those singular safety margins are superimposed to a total safety margin which are relevant. The more the uncertainties have to be taken into account, the total safety margin to be applied, consequently will be larger. If some sources of uncertainty can be eliminated totally or can be minimized (for instance by a more reliable calculational procedure of the component loading or by more precise material characteristics), the total safety margin can be reduced. In this contribution the different procedures for the definition of safety margins within the integrity assessment by means of fracture mechanics procedures will be discussed. (orig.)

  20. Lower bound earthquake magnitude for probabilistic seismic hazard evaluation

    International Nuclear Information System (INIS)

    McCann, M.W. Jr.; Reed, J.W.

    1990-01-01

    This paper presents the results of a study that develops an engineering and seismological basis for selecting a lower-bound magnitude (LBM) for use in seismic hazard assessment. As part of a seismic hazard analysis the range of earthquake magnitudes that are included in the assessment of the probability of exceedance of ground motion must be defined. The upper-bound magnitude is established by earth science experts based on their interpretation of the maximum size of earthquakes that can be generated by a seismic source. The lower-bound or smallest earthquake that is considered in the analysis must also be specified. The LBM limits the earthquakes that are considered in assessing the probability that specified ground motion levels are exceeded. In the past there has not been a direct consideration of the appropriate LBM value that should be used in a seismic hazard assessment. This study specifically looks at the selection of a LBM for use in seismic hazard analyses that are input to the evaluation/design of nuclear power plants (NPPs). Topics addressed in the evaluation of a LBM are earthquake experience data at heavy industrial facilities, engineering characteristics of ground motions associated with small-magnitude earthquakes, probabilistic seismic risk assessments (seismic PRAs), and seismic margin evaluations. The results of this study and the recommendations concerning a LBM for use in seismic hazard assessments are discussed. (orig.)

  1. Raw ODEC Bathy2000 CHIRP subbottom profiler - CHIRP high-resolution Seismic Profile data for the U.S. Arctic Continental Margin.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — ODEC Bathy2000 CHIRP subbottom profiler - CHIRP high-resolution Seismic Profile data were collected in Raw ODEC Bathy2000 CHIRP dat Datagram Format.

  2. A probabilistic seismic risk assessment procedure for nuclear power plants: (I) Methodology

    Science.gov (United States)

    Huang, Y.-N.; Whittaker, A.S.; Luco, N.

    2011-01-01

    A new procedure for probabilistic seismic risk assessment of nuclear power plants (NPPs) is proposed. This procedure modifies the current procedures using tools developed recently for performance-based earthquake engineering of buildings. The proposed procedure uses (a) response-based fragility curves to represent the capacity of structural and nonstructural components of NPPs, (b) nonlinear response-history analysis to characterize the demands on those components, and (c) Monte Carlo simulations to determine the damage state of the components. The use of response-rather than ground-motion-based fragility curves enables the curves to be independent of seismic hazard and closely related to component capacity. The use of Monte Carlo procedure enables the correlation in the responses of components to be directly included in the risk assessment. An example of the methodology is presented in a companion paper to demonstrate its use and provide the technical basis for aspects of the methodology. ?? 2011 Published by Elsevier B.V.

  3. An assessment of the low seismic risk of the inherently safe sodium advanced fast reactor (SAFR)

    International Nuclear Information System (INIS)

    Rutherford, P.D.

    1988-01-01

    A recent probabilistic risk assessment (PRA) of the sodium advanced fast reactor (SAFR) demonstrated the inherently low risk of advanced liquid-metal, pool-type fast reactors with inherent safety systems. As a result, it was recognized that external events, especially seismic events, may not only be a major contributor to risk (as shown in several LWR PRAs) but also may completely dominate the risk. Accordingly, a seismic risk assessment has been completed for SAFR, which resulted in a core damage frequency of 2 x 10 -7 /year and a large release frequency of 4 x 10 -9 /year. This paper reports that public health risk in terms of early fatality risk and latent fatality risk were also several orders of magnitude below the NRC safety goals and below recent LWR risks reported in NUREB/CR1150

  4. Assessment of important seismic provisions of EBCS 8 - 1995 from ...

    African Journals Online (AJOL)

    Only horizontal earthquake excitation of the systems is treated, as this causes the most important effects on building structures. Many concepts that are unknown to the average structural designer, but specified by the Code for strict adherence are clarified and critically assessed. The design spectra of the Code are compared ...

  5. Input parameters for the statistical seismic hazard assessment in central part of Romania territory using crustal earthquakes

    International Nuclear Information System (INIS)

    Moldovan, A.I.; Bazacliu, O.; Popescu, E.

    2004-01-01

    The seismic hazard assessment in dense-populated geographical regions and subsequently the design of the strategic objectives (dams, nuclear power plants, etc.) are based on the knowledge of the seismicity parameters of the seismic sources which can generate ground motion amplitudes above the minimum level considered risky at the specific site and the way the seismic waves propagate between the focus and the site. The purpose of this paper is to provide a set of information required for a probabilistic assessment of the seismic hazard in the central Romanian territory relative to the following seismic sources: Fagaras zone (FC), Campulung zone (CP), and Transilvania zone (TD) all of them in the crust domain. Extremely vulnerable objectives are present in the central part of Romania, including cities of Pitesti and Sibiu and the 'Vidraru' dam. The analysis that we propose implies: (1) geometrical definition of the seismic sources, (2) estimation of the maximum possible magnitude, (3) estimation of the frequency - magnitude relationship and (4) estimation of the attenuation laws. As an example, the obtained input parameters are used to evaluate the seismic hazard distribution due to the crustal earthquakes applying the McGuire's procedure (1976). These preliminary results are in good agreement with the previous research based on deterministic approach (Radulian et al., 2000). (authors)

  6. Coupling mode-destination accessibility with seismic risk assessment to identify at-risk communities

    International Nuclear Information System (INIS)

    Miller, Mahalia; Baker, Jack W.

    2016-01-01

    In this paper, we develop a framework for coupling mode-destination accessibility with quantitative seismic risk assessment to identify communities at high risk for travel disruptions after an earthquake. Mode-destination accessibility measures the ability of people to reach destinations they desire. We use a probabilistic seismic risk assessment procedure, including a stochastic set of earthquake events, ground-motion intensity maps, damage maps, and realizations of traffic and accessibility impacts. For a case study of the San Francisco Bay Area, we couple our seismic risk framework with a practical activity-based traffic model. As a result, we quantify accessibility risk probabilistically by community and household type. We find that accessibility varies more strongly as a function of travelers' geographic location than as a function of their income class, and we identify particularly at-risk communities. We also observe that communities more conducive to local trips by foot or bike are predicted to be less impacted by losses in accessibility. This work shows the potential to link quantitative risk assessment methodologies with high-resolution travel models used by transportation planners. Quantitative risk metrics of this type should have great utility for planners working to reduce risk to a region's infrastructure systems. - Highlights: • We couple mode-destination accessibility with probabilistic seismic risk assessment. • Results identify communities at high risk for post-earthquake travel disruptions. • Accessibility varies more as a function of home location than by income. • Our model predicts reduced accessibility risk for more walking-friendly communities.

  7. Preliminary seismic hazard assessment, shallow seismic refraction and resistivity sounding studies for future urban planning at the Gebel Umm Baraqa area, Egypt

    International Nuclear Information System (INIS)

    Khalil, Mohamed H; Hanafy, Sherif M; Gamal, Mohamed A

    2008-01-01

    Gebel Umm Baraqa Fan, west Gulf of Aqaba, Sinai, is one of the most important tourism areas in Egypt. However, it is located on the active Dead Sea-Gulf of Aqaba Levant transform fault system. Geophysical studies, including fresh water aquifer delineation, shallow seismic refraction, soil characterization and preliminary seismic hazard assessment, were conducted to help in future city planning. A total of 11 vertical electrical soundings (1000–3000 m maximum AB/2) and three bore-holes were drilled in the site for the analysis of ground water, total dissolved solids (TDS) and fresh water aquifer properties. The interpretation of the one-dimensional (1D) inversion of the resistivity data delineated the fresh water aquifer and determined its hydro-geologic parameters. Eleven shallow seismic refraction profiles (125 m in length) have been collected and interpreted using the generalized reciprocal method, and the resulting depth–velocity models were verified using an advanced finite difference (FD) technique. Shallow seismic refraction effectively delineates two subsurface layers (VP ∼ 450 m s −1 and VP ∼ 1000 m s −1 ). A preliminary seismic hazard assessment in Umm Baraqa has produced an estimate of the probabilistic peak ground acceleration hazard in the study area. A recent and historical earthquake catalog for the time period 2200 BC to 2006 has been compiled for the area. New accurate seismic source zoning is considered because such details affect the degree of hazard in the city. The estimated amount of PGA reveals values ranging from 250 to 260 cm s −2 in the bedrock of the Umm Baraqa area during a 100 year interval (a suitable time window for buildings). Recommendations as to suitable types of buildings, considering the amount of shaking and the aquifer properties given in this study, are expected to be helpful for the Umm Baraqa area

  8. Active fault and other geological studies for seismic assessment: present state and problems

    International Nuclear Information System (INIS)

    Kakimi, Toshihiro

    1997-01-01

    Evaluation system of earthquakes from an active fault is, in Japan, based on the characteristic earthquake model of a wide sense that postulates essentially the same (nearly the maximum) magnitude and recurrence interval during the recent geological times. Earthquake magnitude M is estimated by empirical relations among M, surface rupture length L, and surface fault displacement D per event of the earthquake faults on land in Japan. Recurrence interval R of faulting/earthquake is calculated from D and the long-term slip rate S of a fault as R=D/S. Grouping or segmentation of complicatedly distributed faults is an important, but difficult problem in order to distinguish a seismogenic fault unit corresponding to an individual characteristic earthquake. If the time t of the latest event is obtained, the 'cautiousness' of a fault can be judged from R-t or t/R. According to this idea, several faults whose t/R exceed 0.5 have been designated as the 'precaution faults' having higher probability of earthquake occurrence than the others. A part of above evaluation has been introduced at first into the seismic-safety examination system of NPPs in 1978. According to the progress of research on active faults, the weight of interest in respect to the seismic hazard assessment shifted gradually from the historic data to the fault data. Most of recent seismic hazard maps have been prepared in consideration with active faults on land in Japan. Since the occurrence of the 1995 Hyogoken-Nanbu earthquake, social attention has been concentrated upon the seismic hazard due to active faults, because this event was generated from a well-known active fault zone that had been warned as a 'precaution fault'. In this paper, a few recent topics on other geological and geotechnical researches aiming at improving the seismic safety of NPPs in Japan were also introduced. (J.P.N.)

  9. Seismic Vulnerability Assessment of a Shallow Two-Story Underground RC Box Structure

    Directory of Open Access Journals (Sweden)

    Jungwon Huh

    2017-07-01

    Full Text Available Tunnels, culverts, and subway stations are the main parts of an integrated infrastructure system. Most of them are constructed by the cut-and-cover method at shallow depths (mainly lower than 30 m of soil deposits, where large-scale seismic ground deformation can occur with lower stiffness and strength of the soil. Therefore, the transverse racking deformation (one of the major seismic ground deformation due to soil shear deformations should be included in the seismic design of underground structures using cost- and time-efficient methods that can achieve robustness of design and are easily understood by engineers. This paper aims to develop a simplified but comprehensive approach relating to vulnerability assessment in the form of fragility curves on a shallow two-story reinforced concrete underground box structure constructed in a highly-weathered soil. In addition, a comparison of the results of earthquakes per peak ground acceleration (PGA is conducted to determine the effective and appropriate number for cost- and time-benefit analysis. The ground response acceleration method for buried structures (GRAMBS is used to analyze the behavior of the structure subjected to transverse seismic loading under quasi-static conditions. Furthermore, the damage states that indicate the exceedance level of the structural strength capacity are described by the results of nonlinear static analyses (or so-called pushover analyses. The Latin hypercube sampling technique is employed to consider the uncertainties associated with the material properties and concrete cover owing to the variation in construction conditions. Finally, a large number of artificial ground shakings satisfying the design spectrum are generated in order to develop the seismic fragility curves based on the defined damage states. It is worth noting that the number of ground motions per PGA, which is equal to or larger than 20, is a reasonable value to perform a structural analysis that

  10. Active fault and other geological studies for seismic assessment: present state and problems

    Energy Technology Data Exchange (ETDEWEB)

    Kakimi, Toshihiro [Nuclear Power Engineering Corp., Tokyo (Japan)

    1997-03-01

    Evaluation system of earthquakes from an active fault is, in Japan, based on the characteristic earthquake model of a wide sense that postulates essentially the same (nearly the maximum) magnitude and recurrence interval during the recent geological times. Earthquake magnitude M is estimated by empirical relations among M, surface rupture length L, and surface fault displacement D per event of the earthquake faults on land in Japan. Recurrence interval R of faulting/earthquake is calculated from D and the long-term slip rate S of a fault as R=D/S. Grouping or segmentation of complicatedly distributed faults is an important, but difficult problem in order to distinguish a seismogenic fault unit corresponding to an individual characteristic earthquake. If the time t of the latest event is obtained, the `cautiousness` of a fault can be judged from R-t or t/R. According to this idea, several faults whose t/R exceed 0.5 have been designated as the `precaution faults` having higher probability of earthquake occurrence than the others. A part of above evaluation has been introduced at first into the seismic-safety examination system of NPPs in 1978. According to the progress of research on active faults, the weight of interest in respect to the seismic hazard assessment shifted gradually from the historic data to the fault data. Most of recent seismic hazard maps have been prepared in consideration with active faults on land in Japan. Since the occurrence of the 1995 Hyogoken-Nanbu earthquake, social attention has been concentrated upon the seismic hazard due to active faults, because this event was generated from a well-known active fault zone that had been warned as a `precaution fault`. In this paper, a few recent topics on other geological and geotechnical researches aiming at improving the seismic safety of NPPs in Japan were also introduced. (J.P.N.)

  11. Generalized Fragility Relationships with Local Site Conditions for Probabilistic Performance-based Seismic Risk Assessment of Bridge Inventories

    Directory of Open Access Journals (Sweden)

    Sivathayalan S.

    2012-01-01

    Full Text Available The current practice of detailed seismic risk assessment cannot be easily applied to all the bridges in a large transportation networks due to limited resources. This paper presents a new approach for seismic risk assessment of large bridge inventories in a city or national bridge network based on the framework of probabilistic performance based seismic risk assessment. To account for the influences of local site effects, a procedure to generate site-specific hazard curves that includes seismic hazard microzonation information has been developed for seismic risk assessment of bridge inventories. Simulated ground motions compatible with the site specific seismic hazard are used as input excitations in nonlinear time history analysis of representative bridges for calibration. A normalizing procedure to obtain generalized fragility relationships in terms of structural characteristic parameters of bridge span and size and longitudinal and transverse reinforcement ratios is presented. The seismic risk of bridges in a large inventory can then be easily evaluated using the normalized fragility relationships without the requirement of carrying out detailed nonlinear time history analysis.

  12. Seaward dipping reflectors along the SW continental margin of India: Evidence for volcanic passive margin

    Digital Repository Service at National Institute of Oceanography (India)

    Ajay, K.K.; Chaubey, A.K.; Krishna, K.S.; Rao, D.G.; Sar, D.

    Multi-channel seismic reflection profiles across the southwest continental margin of India (SWCMI) show presence of westerly dipping seismic reflectors beneath sedimentary strata along the western flank of the Laccadive Ridge-northernmost part...

  13. Seismic hazard assessment in the Catania and Siracusa urban areas (Italy) through different approaches

    Science.gov (United States)

    Panzera, Francesco; Lombardo, Giuseppe; Rigano, Rosaria

    2010-05-01

    The seismic hazard assessment (SHA) can be performed using either Deterministic or Probabilistic approaches. In present study a probabilistic analysis was carried out for the Catania and Siracusa towns using two different procedures: the 'site' (Albarello and Mucciarelli, 2002) and the 'seismotectonic' (Cornell 1968; Esteva, 1967) methodologies. The SASHA code (D'Amico and Albarello, 2007) was used to calculate seismic hazard through the 'site' approach, whereas the CRISIS2007 code (Ordaz et al., 2007) was adopted in the Esteva-Cornell procedure. According to current international conventions for PSHA (SSHAC, 1997), a logic tree approach was followed to consider and reduce the epistemic uncertainties, for both seismotectonic and site methods. The code SASHA handles the intensity data taking into account the macroseismic information of past earthquakes. CRISIS2007 code needs, as input elements, a seismic catalogue tested for completeness, a seismogenetic zonation and ground motion predicting equations. Data concerning the characterization of regional seismic sources and ground motion attenuation properties were taken from the literature. Special care was devoted to define source zone models, taking into account the most recent studies on regional seismotectonic features and, in particular, the possibility of considering the Malta escarpment as a potential source. The combined use of the above mentioned approaches allowed us to obtain useful elements to define the site seismic hazard in Catania and Siracusa. The results point out that the choice of the probabilistic model plays a fundamental role. It is indeed observed that when the site intensity data are used, the town of Catania shows hazard values higher than the ones found for Siracusa, for each considered return period. On the contrary, when the Esteva-Cornell method is used, Siracusa urban area shows higher hazard than Catania, for return periods greater than one hundred years. The higher hazard observed

  14. Seismic assessment of selected buildings and equipment contents of a DOE facility in UBC zone 2A

    International Nuclear Information System (INIS)

    Tong, W.H.; Deneff, C.; Griffin, M.J.

    1991-01-01

    A preliminary seismic risk assessment for selected buildings and representative equipment contents in Allied-Signal Kansas City Division was performed to identify potential seismic hazard and weakness. The site is located in the Uniform Building Code Zone 2A. The selected building structures were constructed between 1940s to 1980s. The performance goal was to qualitatively assess the potential for loss of toxic or hazardous materials and injury to plant personnel due to an earthquake event

  15. Proceedings of third Indo-German workshop and theme meeting on seismic safety of structures, risk assessment and disaster mitigation

    International Nuclear Information System (INIS)

    Reddy, G.R.; Parulekar, Y.M.

    2007-01-01

    This Indo-German workshop focuses and emphasises the current research and development activities in both the countries. Themes of this meeting are Earthquake Hazard and Vulnerability Assessment, Risk Assessment Techniques, Seismic Risk to Mega Cities, Testing and Evaluation of Structures and Components, Base Isolation and other Control Techniques, Seismic Strengthening of Structures, Design Practices and Specifications, Remote Sensing and GIS Applications, Structural Materials and Composites, Containment and Other Special Structures. Papers relevant to INIS are indexed separately

  16. Assessment of the impact of degraded shear wall stiffnesses on seismic plant risk and seismic design loads

    International Nuclear Information System (INIS)

    Klamerus, E.W.; Bohn, M.P.; Johnson, J.J.; Asfura, A.P.; Doyle, D.J.

    1994-02-01

    Test results sponsored by the USNRC have shown that reinforced shear wall (Seismic Category I) structures exhibit stiffnesses and natural frequencies which are smaller than those calculated in the design process. The USNRC has sponsored Sandia National Labs to perform an evaluation of the effects of the reduced frequencies on several existing seismic PRAs in order to determine the seismic risk implications inherent in these test results. This report presents the results for the re-evaluation of the seismic risk for three nuclear power plants: the Peach Bottom Atomic Power Station, the Zion Nuclear Power Plant, and Arkansas Nuclear One -- Unit 1 (ANO-1). Increases in core damage frequencies for seismic initiated events at Peach Bottom were 25 to 30 percent (depending on whether LLNL or EPRI hazard curves were used). At the ANO-1 site, the corresponding increases in plant risk were 10 percent (for each set of hazard curves). Finally, at Zion, there was essentially no change in the computed core damage frequency when the reduction in shear wall stiffness was included. In addition, an evaluation of deterministic ''design-like'' structural dynamic calculations with and without the shear stiffness reductions was made. Deterministic loads calculated for these two cases typically increased on the order of 10 to 20 percent for the affected structures

  17. Critical assessment of seismic and geomechanics literature related to a high-level nuclear waste underground repository

    Energy Technology Data Exchange (ETDEWEB)

    Kana, D.D.; Vanzant, B.W.; Nair, P.K. [Southwest Research Inst., San Antonio, TX (USA). Center for Nuclear Waste Regulatory Analyses; Brady, B.H.G. [ITASCA Consulting Group, Inc., Minneapolis, MN (USA)

    1991-06-01

    A comprehensive literature assessment has been conducted to determine the nature and scope of technical information available to characterize the seismic performance of an underground repository and associated facilities. Significant deficiencies were identified in current practices for prediction of seismic response of underground excavations in jointed rock. Conventional analytical methods are based on a continuum representation of the host rock mass. Field observations and laboratory experiments indicate that, in jointed rock, the behavior of the joints controls the overall performance of underground excavations. Further, under repetitive seismic loading, shear displacement develops progressively at block boundaries. Field observations correlating seismicity and groundwater conditions have provided significant information on hydrological response to seismic events. However, lack of a comprehensive model of geohydrological response to seismicity has limited the transportability conclusions from field observations. Based on the literature study, matters requiring further research in relation to the Yucca Mountain repository are identified. The report focuses on understanding seismic processes in fractured tuff, and provides a basis for work on the geohydrologic response of a seismically disturbed rock mass. 220 refs., 43 figs., 11 tabs.

  18. Critical assessment of seismic and geomechanics literature related to a high-level nuclear waste underground repository

    International Nuclear Information System (INIS)

    Kana, D.D.; Vanzant, B.W.; Nair, P.K.

    1991-06-01

    A comprehensive literature assessment has been conducted to determine the nature and scope of technical information available to characterize the seismic performance of an underground repository and associated facilities. Significant deficiencies were identified in current practices for prediction of seismic response of underground excavations in jointed rock. Conventional analytical methods are based on a continuum representation of the host rock mass. Field observations and laboratory experiments indicate that, in jointed rock, the behavior of the joints controls the overall performance of underground excavations. Further, under repetitive seismic loading, shear displacement develops progressively at block boundaries. Field observations correlating seismicity and groundwater conditions have provided significant information on hydrological response to seismic events. However, lack of a comprehensive model of geohydrological response to seismicity has limited the transportability conclusions from field observations. Based on the literature study, matters requiring further research in relation to the Yucca Mountain repository are identified. The report focuses on understanding seismic processes in fractured tuff, and provides a basis for work on the geohydrologic response of a seismically disturbed rock mass. 220 refs., 43 figs., 11 tabs

  19. The role of IAEA in the seismic assessment and upgrading of existing NPPs. Seismic safety of nuclear power plants in Eastern Europe

    Energy Technology Data Exchange (ETDEWEB)

    Guerpinar, A; Godoy, A [International Atomic Energy Agency, Vienna (IAEA). Div. of Nuclear Installation Safety

    1997-03-01

    This paper summarizes the work performed by the International Atomic Energy Agency in the areas of safety reviews and applied research in support of programmes for the assessment and enhancement of seismic safety in Eastern Europe and in particular WWER type nuclear power plants during the past seven years. Three major topics are discussed; engineering safety review services in relation to external events, technical guidelines for the assessment and upgrading of WWER type nuclear power plants, and the Coordinated Research Programme on `Benchmark study for the seismic analysis and testing of WWER type nuclear power plants`. These topics are summarized in a way to provide an overview of the past and present safety situation in selected WWER type plants which are all located in Eastern European countries. Main conclusion of the paper is that although there is now a thorough understanding of the seismic safety issues in these operating nuclear power plants, the implementation of seismic upgrades to structures, systems and components are lagging behind, particularly for those cases in which the re-evaluation indicated the necessity to strengthen the safety related structures or install new safety systems. (author)

  20. The role of IAEA in the seismic assessment and upgrading of existing NPPs. Seismic safety of nuclear power plants in Eastern Europe

    International Nuclear Information System (INIS)

    Guerpinar, A.; Godoy, A.; . Div. of Nuclear Installation Safety)

    1997-01-01

    This paper summarizes the work performed by the International Atomic Energy Agency in the areas of safety reviews and applied research in support of programmes for the assessment and enhancement of seismic safety in Eastern Europe and in particular WWER type nuclear power plants during the past seven years. Three major topics are discussed; engineering safety review services in relation to external events, technical guidelines for the assessment and upgrading of WWER type nuclear power plants, and the Coordinated Research Programme on 'Benchmark study for the seismic analysis and testing of WWER type nuclear power plants'. These topics are summarized in a way to provide an overview of the past and present safety situation in selected WWER type plants which are all located in Eastern European countries. Main conclusion of the paper is that although there is now a thorough understanding of the seismic safety issues in these operating nuclear power plants, the implementation of seismic upgrades to structures, systems and components are lagging behind, particularly for those cases in which the re-evaluation indicated the necessity to strengthen the safety related structures or install new safety systems. (author)

  1. Risk assessment and early warning systems for industrial facilities in seismic zones

    International Nuclear Information System (INIS)

    Salzano, Ernesto; Garcia Agreda, Anita; Di Carluccio, Antonio; Fabbrocino, Giovanni

    2009-01-01

    Industrial equipments and systems can suffer structural damage when hit by earthquakes, so that accidental scenarios as fire, explosion and dispersion of toxic substances can take place. As a result, overall damage to people, environment and properties increases. The present paper deals with seismic risk analysis of industrial facilities where atmospheric storage tanks (anchored or unanchored to ground), horizontal pressurised tanks, reactors and pumps are installed. Simplified procedures and methodologies based on historical database and literature data on natural-technological (Na-Tech) accidents for seismic risk assessment are discussed. Equipment-specific fragility curves have been thus derived depending on a single earthquake measure, peak ground acceleration (PGA). Fragility parameters have been then transformed to linear probit coefficients in order to obtain reliable threshold values for earthquake intensity measure, both for structural damage and loss of containment. These threshold values are of great interest when development of active and passive mitigation actions and systems, safety management, and the implementation of early warning system are concerned. The approach is general and can be implemented in any available code or procedure for risk assessment. Some results of seismic analysis of atmospheric storage tanks are also presented for validation.

  2. Life-cycle cost assessment of optimally designed reinforced concrete buildings under seismic actions

    International Nuclear Information System (INIS)

    Mitropoulou, Chara Ch.; Lagaros, Nikos D.; Papadrakakis, Manolis

    2011-01-01

    Life-cycle cost analysis (LCCA) is an assessment tool for studying the performance of systems in many fields of engineering. In earthquake engineering LCCA demands the calculation of the cost components that are related to the performance of the structure in multiple earthquake hazard levels. Incremental static and dynamic analyses are two procedures that can be used for estimating the seismic capacity of a structural system and can therefore be incorporated into the LCCA methodology. In this work the effect of the analysis procedure, the number of seismic records imposed, the performance criterion used and the structural type (regular or irregular) is investigated, on the life-cycle cost analysis of 3D reinforced concrete structures. Furthermore, the influence of uncertainties on the seismic response of structural systems and their impact on LCCA is examined. The uncertainty on the material properties, the cross-section dimensions and the record-incident angle is taking into account with the incorporation of the Latin hypercube sampling method into the incremental dynamic analysis procedure. In addition, the LCCA methodology is used as an assessment tool for the designs obtained by means of prescriptive and performance-based optimum design methodologies. The first one is obtained from a single-objective optimization problem, where the initial construction cost was the objective to be minimized, while the second one as a two-objective optimization problem where the life-cycle cost was the additional objective also to be minimized.

  3. Neo-Deterministic and Probabilistic Seismic Hazard Assessments: a Comparative Analysis

    Science.gov (United States)

    Peresan, Antonella; Magrin, Andrea; Nekrasova, Anastasia; Kossobokov, Vladimir; Panza, Giuliano F.

    2016-04-01

    Objective testing is the key issue towards any reliable seismic hazard assessment (SHA). Different earthquake hazard maps must demonstrate their capability in anticipating ground shaking from future strong earthquakes before an appropriate use for different purposes - such as engineering design, insurance, and emergency management. Quantitative assessment of maps performances is an essential step also in scientific process of their revision and possible improvement. Cross-checking of probabilistic models with available observations and independent physics based models is recognized as major validation procedure. The existing maps from the classical probabilistic seismic hazard analysis (PSHA), as well as those from the neo-deterministic analysis (NDSHA), which have been already developed for several regions worldwide (including Italy, India and North Africa), are considered to exemplify the possibilities of the cross-comparative analysis in spotting out limits and advantages of different methods. Where the data permit, a comparative analysis versus the documented seismic activity observed in reality is carried out, showing how available observations about past earthquakes can contribute to assess performances of the different methods. Neo-deterministic refers to a scenario-based approach, which allows for consideration of a wide range of possible earthquake sources as the starting point for scenarios constructed via full waveforms modeling. The method does not make use of empirical attenuation models (i.e. Ground Motion Prediction Equations, GMPE) and naturally supplies realistic time series of ground shaking (i.e. complete synthetic seismograms), readily applicable to complete engineering analysis and other mitigation actions. The standard NDSHA maps provide reliable envelope estimates of maximum seismic ground motion from a wide set of possible scenario earthquakes, including the largest deterministically or historically defined credible earthquake. In addition

  4. A regulatory view of the seismic assessment of existing nuclear structures in the United Kingdom

    International Nuclear Information System (INIS)

    Inkester, J.E.

    2001-01-01

    The paper describes the background to the seismic assessment of existing nuclear structures in the United Kingdom. Nuclear installations in this country were not designed specifically to resist earthquakes until the nineteen-seventies, although older plants were robustly constructed. The seismic capability of these older installations is now being evaluated as part of the periodic safety reviews which nuclear licensees are required to carry out. The regulatory requirements which set the framework for these studies are explained. The licensees' processes of hazard appraisal and examination of the response of the structure are briefly summarized. Regulatory views on some of the criteria used to judge the adequacy of safety are discussed. Finally the paper provides some comments on future initiatives and possible areas of development. (author)

  5. Deep continental margin reflectors

    Science.gov (United States)

    Ewing, J.; Heirtzler, J.; Purdy, M.; Klitgord, Kim D.

    1985-01-01

    In contrast to the rarity of such observations a decade ago, seismic reflecting and refracting horizons are now being observed to Moho depths under continental shelves in a number of places. These observations provide knowledge of the entire crustal thickness from the shoreline to the oceanic crust on passive margins and supplement Consortium for Continental Reflection Profiling (COCORP)-type measurements on land.

  6. Local seismic hazard assessment in explosive volcanic settings by 3D numerical analyses

    Science.gov (United States)

    Razzano, Roberto; Pagliaroli, Alessandro; Moscatelli, Massimiliano; Gaudiosi, Iolanda; Avalle, Alessandra; Giallini, Silvia; Marcini, Marco; Polpetta, Federica; Simionato, Maurizio; Sirianni, Pietro; Sottili, Gianluca; Vignaroli, Gianluca; Bellanova, Jessica; Calamita, Giuseppe; Perrone, Angela; Piscitelli, Sabatino

    2017-04-01

    This work deals with the assessment of local seismic response in the explosive volcanic settings by reconstructing the subsoil model of the Stracciacappa maar (Sabatini Volcanic District, central Italy), whose pyroclastic succession records eruptive phases ended about 0.09 Ma ago. Heterogeneous characteristics of the Stracciacappa maar (stratification, structural setting, lithotypes, and thickness variation of depositional units) make it an ideal case history for understanding mechanisms and processes leading to modifications of amplitude-frequency-duration of seismic waves generated at earthquake sources and propagating through volcanic settings. New geological map and cross sections, constrained with recently acquired geotechnical and geophysical data, illustrate the complex geometric relationships among different depositional units forming the maar. A composite interfingering between internal lacustrine sediments and epiclastic debris, sourced from the rim, fills the crater floor; a 45 meters thick continuous coring borehole was drilled in the maar with sampling of undisturbed samples. Electrical Resistivity Tomography surveys and 2D passive seismic arrays were also carried out for constraining the geological model and the velocity profile of the S-waves, respectively. Single station noise measurements were collected in order to define natural amplification frequencies. Finally, the nonlinear cyclic soil behaviour was investigated through simple shear tests on the undisturbed samples. The collected dataset was used to define the subsoil model for 3D finite difference site response numerical analyses by using FLAC 3D software (ITASCA). Moreover, 1D and 2D numerical analyses were carried out for comparison purposes. Two different scenarios were selected as input motions: a moderate magnitude (volcanic event) and a high magnitude (tectonic event). Both earthquake scenarios revealed significant ground motion amplification (up to 15 in terms of spectral acceleration

  7. Seismic reliability assessment of RC structures including soil–structure interaction using wavelet weighted least squares support vector machine

    International Nuclear Information System (INIS)

    Khatibinia, Mohsen; Javad Fadaee, Mohammad; Salajegheh, Javad; Salajegheh, Eysa

    2013-01-01

    An efficient metamodeling framework in conjunction with the Monte-Carlo Simulation (MCS) is introduced to reduce the computational cost in seismic reliability assessment of existing RC structures. In order to achieve this purpose, the metamodel is designed by combining weighted least squares support vector machine (WLS-SVM) and a wavelet kernel function, called wavelet weighted least squares support vector machine (WWLS-SVM). In this study, the seismic reliability assessment of existing RC structures with consideration of soil–structure interaction (SSI) effects is investigated in accordance with Performance-Based Design (PBD). This study aims to incorporate the acceptable performance levels of PBD into reliability theory for comparing the obtained annual probability of non-performance with the target values for each performance level. The MCS method as the most reliable method is utilized to estimate the annual probability of failure associated with a given performance level in this study. In WWLS-SVM-based MCS, the structural seismic responses are accurately predicted by WWLS-SVM for reducing the computational cost. To show the efficiency and robustness of the proposed metamodel, two RC structures are studied. Numerical results demonstrate the efficiency and computational advantages of the proposed metamodel for the seismic reliability assessment of structures. Furthermore, the consideration of the SSI effects in the seismic reliability assessment of existing RC structures is compared to the fixed base model. It shows which SSI has the significant influence on the seismic reliability assessment of structures.

  8. Incorporating latitudinal and central–marginal trends in assessing genetic variation across species ranges

    Science.gov (United States)

    Qinfeng Guo

    2012-01-01

    The genetic variation across a species’ range is an important factor in speciation and conservation, yet searching for general patterns and underlying causes remains challenging. While the majority of comparisons between central and marginal populations have revealed a general central–marginal (C-M) decline in genetic diversity, others show no clear pattern. Similarly...

  9. Specimen Shrinkage and Its Influence on Margin Assessment in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Badrul H. Yeap

    2007-07-01

    Conclusion: Breast specimens undergo shrinkage after histological fixation, losing more than a third of their original closest free margin, whilst the tumour itself does not shrink substantially. This phenomenon has vital implications in the accuracy of margin analysis and consequent decisions on further management, including re-operation and the institution of adjuvant radiotherapy.

  10. Implications from palaeoseismological investigations at the Markgrafneusiedl Fault (Vienna Basin, Austria for seismic hazard assessment

    Directory of Open Access Journals (Sweden)

    E. Hintersberger

    2018-02-01

    Full Text Available Intraplate regions characterized by low rates of seismicity are challenging for seismic hazard assessment, mainly for two reasons. Firstly, evaluation of historic earthquake catalogues may not reveal all active faults that contribute to regional seismic hazard. Secondly, slip rate determination is limited by sparse geomorphic preservation of slowly moving faults. In the Vienna Basin (Austria, moderate historical seismicity (Imax, obs ∕ Mmax, obs = 8∕5.2 concentrates along the left-lateral strike-slip Vienna Basin Transfer Fault (VBTF. In contrast, several normal faults branching out from the VBTF show neither historical nor instrumental earthquake records, although geomorphological data indicate Quaternary displacement along those faults. Here, located about 15 km outside of Vienna, the Austrian capital, we present a palaeoseismological dataset of three trenches that cross one of these splay faults, the Markgrafneusiedl Fault (MF, in order to evaluate its seismic potential. Comparing the observations of the different trenches, we found evidence for five to six surface-breaking earthquakes during the last 120 kyr, with the youngest event occurring at around 14 ka. The derived surface displacements lead to magnitude estimates ranging between 6.2 ± 0.5 and 6.8 ± 0.4. Data can be interpreted by two possible slip models, with slip model 1 showing more regular recurrence intervals of about 20–25 kyr between the earthquakes with M ≥ 6.5 and slip model 2 indicating that such earthquakes cluster in two time intervals in the last 120 kyr. Direct correlation between trenches favours slip model 2 as the more plausible option. Trench observations also show that structural and sedimentological records of strong earthquakes with small surface offset have only low preservation potential. Therefore, the earthquake frequency for magnitudes between 6 and 6.5 cannot be constrained by the trenching records. Vertical

  11. Implications from palaeoseismological investigations at the Markgrafneusiedl Fault (Vienna Basin, Austria) for seismic hazard assessment

    Science.gov (United States)

    Hintersberger, Esther; Decker, Kurt; Lomax, Johanna; Lüthgens, Christopher

    2018-02-01

    Intraplate regions characterized by low rates of seismicity are challenging for seismic hazard assessment, mainly for two reasons. Firstly, evaluation of historic earthquake catalogues may not reveal all active faults that contribute to regional seismic hazard. Secondly, slip rate determination is limited by sparse geomorphic preservation of slowly moving faults. In the Vienna Basin (Austria), moderate historical seismicity (Imax, obs / Mmax, obs = 8/5.2) concentrates along the left-lateral strike-slip Vienna Basin Transfer Fault (VBTF). In contrast, several normal faults branching out from the VBTF show neither historical nor instrumental earthquake records, although geomorphological data indicate Quaternary displacement along those faults. Here, located about 15 km outside of Vienna, the Austrian capital, we present a palaeoseismological dataset of three trenches that cross one of these splay faults, the Markgrafneusiedl Fault (MF), in order to evaluate its seismic potential. Comparing the observations of the different trenches, we found evidence for five to six surface-breaking earthquakes during the last 120 kyr, with the youngest event occurring at around 14 ka. The derived surface displacements lead to magnitude estimates ranging between 6.2 ± 0.5 and 6.8 ± 0.4. Data can be interpreted by two possible slip models, with slip model 1 showing more regular recurrence intervals of about 20-25 kyr between the earthquakes with M ≥ 6.5 and slip model 2 indicating that such earthquakes cluster in two time intervals in the last 120 kyr. Direct correlation between trenches favours slip model 2 as the more plausible option. Trench observations also show that structural and sedimentological records of strong earthquakes with small surface offset have only low preservation potential. Therefore, the earthquake frequency for magnitudes between 6 and 6.5 cannot be constrained by the trenching records. Vertical slip rates of 0.02-0.05 mm a-1 derived from the

  12. Evaluation of response factors for seismic probabilistic safety assessment of nuclear power plants

    International Nuclear Information System (INIS)

    Ebisawa, K.; Abe, K.; Muramatsu, K.; Itoh, M.; Kohno, K.; Tanaka, T.

    1994-01-01

    This paper presents a method for evaluating 'response factors' of components in nuclear power plants for use in a seismic probabilistic safety assessment (PSA). The response factor here is a measure of conservatism included in response calculations in seismic design analysis of components and is defined as a ratio of conservative design resonse to actual response. This method has the following characteristic features: (1) The components are classified into several groups based on the differences in their location and in the vibration models used in design response analyses; (2) the response factors are decomposed into subfactors corresponding to the stages of the seismic response analyses in the design practices; (3) the response factors for components are calculated as products of subfactors; (4) the subfactors are expressed either as a single value or as a function of parameters that influence the response of components. This paper describes the outline of this method and results from an application to a sample problem in which response factors were quantified for examples of components selected from the groups. (orig.)

  13. Seismic risk assessment of Trani's Cathedral bell tower in Apulia, Italy

    Science.gov (United States)

    Diaferio, Mariella; Foti, Dora

    2017-09-01

    The present paper deals with the evaluation of the seismic vulnerability of slender historical buildings; these structures, in fact, may manifest a high risk with respect to seismic actions as usually they have been designed to resist to gravitational loads only, and are characterized by a high flexibility. To evaluate this behavior, the bell tower of the Trani's Cathedral is investigated. The tower is 57 m tall and is characterized by an unusual building typology, i.e., the walls are composed of a concrete core coupled with external masonry stones. The dynamic parameters and the mechanical properties of the tower have been evaluated on the basis of an extensive experimental campaign that made use of ambient vibration tests and ground penetrating radar tests. Such data have been utilized to calibrate a numerical model of the examined tower. A linear static analysis, a dynamic analysis and a nonlinear static analysis have been carried out on such model to evaluate the displacement capacity of the tower and the seismic risk assessment in accordance with the Italian guidelines.

  14. PROBABILISTIC SEISMIC ASSESSMENT OF BASE-ISOLATED NPPS SUBJECTED TO STRONG GROUND MOTIONS OF TOHOKU EARTHQUAKE

    Directory of Open Access Journals (Sweden)

    AHMER ALI

    2014-10-01

    Full Text Available The probabilistic seismic performance of a standard Korean nuclear power plant (NPP with an idealized isolation is investigated in the present work. A probabilistic seismic hazard analysis (PSHA of the Wolsong site on the Korean peninsula is performed by considering peak ground acceleration (PGA as an earthquake intensity measure. A procedure is reported on the categorization and selection of two sets of ground motions of the Tohoku earthquake, i.e. long-period and common as Set A and Set B respectively, for the nonlinear time history response analysis of the base-isolated NPP. Limit state values as multiples of the displacement responses of the NPP base isolation are considered for the fragility estimation. The seismic risk of the NPP is further assessed by incorporation of the rate of frequency exceedance and conditional failure probability curves. Furthermore, this framework attempts to show the unacceptable performance of the isolated NPP in terms of the probabilistic distribution and annual probability of limit states. The comparative results for long and common ground motions are discussed to contribute to the future safety of nuclear facilities against drastic events like Tohoku.

  15. Damage assessment for seismic response of recycled concrete filled steel tube columns

    Science.gov (United States)

    Huang, Yijie; Xiao, Jianzhuang; Shen, Luming

    2016-09-01

    A model for evaluating structural damage of recycled aggregate concrete filled steel tube (RCFST) columns under seismic effects is proposed in this paper. The proposed model takes the lateral deformation and the effect of repeated cyclic loading into account. Available test results were collected and utilized to calibrate the parameters of the proposed model. A seismic test for six RCFST columns was also performed to validate the proposed damage assessment model. The main test parameters were the recycled coarse aggregate (RCA) replacement percentage and the bond-slip property. The test results indicated that the seismic performance of the RCFST member depends on the RCA contents and their damage index increases as the RCA replacement percentage increases. It is also indicated that the damage degree of RCFST changes with the variation of the RCA replacement percentage. Finally, comparisons between the RCA contents, lateral deformation ratio and damage degree were implemented. It is suggested that an improvement procedure should be implemented in order to compensate for the performance difference between the RCFST and normal concrete filled steel tubes (CFST).

  16. Probabilistic seismic assessment of base-isolated NPPs subjected to strong ground motions of Tohoku earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Ahmer; Hayah, Nadin Abu; Kim, Doo Kie [Dept. of Civil and Environmental Engineering, Kunsan National University, Kunsan (Korea, Republic of); Cho, Sung Gook [R and D Center, JACE KOREA Company, Gyeonggido (Korea, Republic of)

    2014-10-15

    The probabilistic seismic performance of a standard Korean nuclear power plant (NPP) with an idealized isolation is investigated in the present work. A probabilistic seismic hazard analysis (PSHA) of the Wolsong site on the Korean peninsula is performed by considering peak ground acceleration (PGA) as an earthquake intensity measure. A procedure is reported on the categorization and selection of two sets of ground motions of the Tohoku earthquake, i.e. long-period and common as Set A and Set B respectively, for the nonlinear time history response analysis of the base-isolated NPP. Limit state values as multiples of the displacement responses of the NPP base isolation are considered for the fragility estimation. The seismic risk of the NPP is further assessed by incorporation of the rate of frequency exceedance and conditional failure probability curves. Furthermore, this framework attempts to show the unacceptable performance of the isolated NPP in terms of the probabilistic distribution and annual probability of limit states. The comparative results for long and common ground motions are discussed to contribute to the future safety of nuclear facilities against drastic events like Tohoku.

  17. Probabilistic seismic hazard assessment for the two layer fault system of Antalya (SW Turkey) area

    Science.gov (United States)

    Dipova, Nihat; Cangir, Bülent

    2017-09-01

    Southwest Turkey, along Mediterranean coast, is prone to large earthquakes resulting from subduction of the African plate under the Eurasian plate and shallow crustal faults. Maximum observed magnitude of subduction earthquakes is Mw = 6.5 whereas that of crustal earthquakes is Mw = 6.6. Crustal earthquakes are sourced from faults which are related with Isparta Angle and Cyprus Arc tectonic structures. The primary goal of this study is to assess seismic hazard for Antalya area (SW Turkey) using a probabilistic approach. A new earthquake catalog for Antalya area, with unified moment magnitude scale, was prepared in the scope of the study. Seismicity of the area has been evaluated by the Gutenberg-Richter recurrence relationship. For hazard computation, CRISIS2007 software was used following the standard Cornell-McGuire methodology. Attenuation model developed by Youngs et al. Seismol Res Lett 68(1):58-73, (1997) was used for deep subduction earthquakes and Chiou and Youngs Earthq Spectra 24(1):173-215, (2008) model was used for shallow crustal earthquakes. A seismic hazard map was developed for peak ground acceleration and for rock ground with a hazard level of a 10% probability of exceedance in 50 years. Results of the study show that peak ground acceleration values on bedrock change between 0.215 and 0.23 g in the center of Antalya.

  18. Seismic hazard and seismic risk assessment based on the unified scaling law for earthquakes: Himalayas and adjacent regions

    Science.gov (United States)

    Nekrasova, A. K.; Kossobokov, V. G.; Parvez, I. A.

    2015-03-01

    For the Himalayas and neighboring regions, the maps of seismic hazard and seismic risk are constructed with the use of the estimates for the parameters of the unified scaling law for earthquakes (USLE), in which the Gutenberg-Richter law for magnitude distribution of seismic events within a given area is applied in the modified version with allowance for linear dimensions of the area, namely, log N( M, L) = A + B (5 - M) + C log L, where N( M, L) is the expected annual number of the earthquakes with magnitude M in the area with linear dimension L. The spatial variations in the parameters A, B, and C for the Himalayas and adjacent regions are studied on two time intervals from 1965 to 2011 and from 1980 to 2011. The difference in A, B, and C between these two time intervals indicates that seismic activity experiences significant variations on a scale of a few decades. With a global consideration of the seismic belts of the Earth overall, the estimates of coefficient A, which determines the logarithm of the annual average frequency of the earthquakes with a magnitude of 5.0 and higher in the zone with a linear dimension of 1 degree of the Earth's meridian, differ by a factor of 30 and more and mainly fall in the interval from -1.1 to 0.5. The values of coefficient B, which describes the balance between the number of earthquakes with different magnitudes, gravitate to 0.9 and range from less than 0.6 to 1.1 and higher. The values of coefficient C, which estimates the fractal dimension of the local distribution of epicenters, vary from 0.5 to 1.4 and higher. In the Himalayas and neighboring regions, the USLE coefficients mainly fall in the intervals of -1.1 to 0.3 for A, 0.8 to 1.3 for B, and 1.0 to 1.4 for C. The calculations of the local value of the expected peak ground acceleration (PGA) from the maximal expected magnitude provided the necessary basis for mapping the seismic hazards in the studied region. When doing this, we used the local estimates of the

  19. Seismic velocity structure of the crust and upper mantle beneath the Texas-Gulf of Mexico margin from joint inversion of Ps and Sp receiver functions and surface wave dispersion

    Science.gov (United States)

    Agrawal, M.; Pulliam, J.; Sen, M. K.

    2013-12-01

    The seismic structure beneath Texas Gulf Coast Plain (GCP) is determined via velocity analysis of stacked common conversion point (CCP) Ps and Sp receiver functions and surface wave dispersion. The GCP is a portion of a ocean-continental transition zone, or 'passive margin', where seismic imaging of lithospheric Earth structure via passive seismic techniques has been rare. Seismic data from a temporary array of 22 broadband stations, spaced 16-20 km apart, on a ~380-km-long profile from Matagorda Island, a barrier island in the Gulf of Mexico, to Johnson City, Texas were employed to construct a coherent image of the crust and uppermost mantle. CCP stacking was applied to data from teleseismic earthquakes to enhance the signal-to-noise ratios of converted phases, such as Ps phases. An inaccurate velocity model, used for time-to-depth conversion in CCP stacking, may produce higher errors, especially in a region of substantial lateral velocity variations. An accurate velocity model is therefore essential to constructing high quality depth-domain images. To find accurate velocity P- and S-wave models, we applied a joint modeling approach that searches for best-fitting models via simulated annealing. This joint inversion approach, which we call 'multi objective optimization in seismology' (MOOS), simultaneously models Ps receiver functions, Sp receiver functions and group velocity surface wave dispersion curves after assigning relative weights for each objective function. Weights are computed from the standard deviations of the data. Statistical tools such as the posterior parameter correlation matrix and posterior probability density (PPD) function are used to evaluate the constraints that each data type places on model parameters. They allow us to identify portions of the model that are well or poorly constrained.

  20. Use of raster-based data layers to model spatial variation of seismotectonic data in probabilistic seismic hazard assessment

    Science.gov (United States)

    Zolfaghari, Mohammad R.

    2009-07-01

    Recent achievements in computer and information technology have provided the necessary tools to extend the application of probabilistic seismic hazard mapping from its traditional engineering use to many other applications. Examples for such applications are risk mitigation, disaster management, post disaster recovery planning and catastrophe loss estimation and risk management. Due to the lack of proper knowledge with regard to factors controlling seismic hazards, there are always uncertainties associated with all steps involved in developing and using seismic hazard models. While some of these uncertainties can be controlled by more accurate and reliable input data, the majority of the data and assumptions used in seismic hazard studies remain with high uncertainties that contribute to the uncertainty of the final results. In this paper a new methodology for the assessment of seismic hazard is described. The proposed approach provides practical facility for better capture of spatial variations of seismological and tectonic characteristics, which allows better treatment of their uncertainties. In the proposed approach, GIS raster-based data models are used in order to model geographical features in a cell-based system. The cell-based source model proposed in this paper provides a framework for implementing many geographically referenced seismotectonic factors into seismic hazard modelling. Examples for such components are seismic source boundaries, rupture geometry, seismic activity rate, focal depth and the choice of attenuation functions. The proposed methodology provides improvements in several aspects of the standard analytical tools currently being used for assessment and mapping of regional seismic hazard. The proposed methodology makes the best use of the recent advancements in computer technology in both software and hardware. The proposed approach is well structured to be implemented using conventional GIS tools.

  1. Seismic evaluation of existing nuclear power plants

    International Nuclear Information System (INIS)

    2003-01-01

    The IAEA nuclear safety standards publications address the site evaluation and the design of new nuclear power plants (NPPs), including seismic hazard assessment and safe seismic design, at the level of the Safety Requirements as well as at the level of dedicated Safety Guides. It rapidly became apparent that the existing nuclear safety standards documents were not adequate for handling specific issues in the seismic evaluation of existing NPPs, and that a dedicated document was necessary. This is the purpose of this Safety Report, which is written in the spirit of the nuclear safety standards and can be regarded as guidance for the interpretation of their intent. Worldwide experience shows that an assessment of the seismic capacity of an existing operating facility can be prompted for the following: (a) Evidence of a greater seismic hazard at the site than expected before, owing to new or additional data and/or to new methods; (b) Regulatory requirements, such as periodic safety reviews, to ensure that the plant has adequate margins for seismic loads; (c) Lack of anti-seismic design or poor anti-seismic design; (d) New technical finding such as vulnerability of some structures (masonry walls) or equipment (relays), other feedback and new experience from real earthquakes. Post-construction evaluation programmes evaluate the current capability of the plant to withstand the seismic concern and identify any necessary upgrades or changes in operating procedures. Seismic qualification is distinguished from seismic evaluation primarily in that seismic qualification is intended to be performed at the design stage of a plant, whereas seismic evaluation is intended to be applied after a plant has been constructed. Although some guidelines do exist for the evaluation of existing NPPs, these are not established at the level of a regulatory guide or its equivalent. Nevertheless, a number of existing NPPs throughout the world have been and are being subjected to review of their

  2. The regulatory requirements, design bases, researches and assessments in the field of Ukrainian NPP's seismic safety

    International Nuclear Information System (INIS)

    Mykolaychuk, O.; Mayboroda, O.; Krytskyy, V.; Karnaukhov, O.

    2001-01-01

    State Nuclear Regulatory Authority of Ukraine (SNRA) pays large attention to problem of nuclear installations seismic stability. As a result the seismic design regulatory guides is revised, additional seismic researches of NPP sites are conducted, seismic reassessment of NPP designs were begun. The experts involved address all seismic related factors under close contact with the staff of NPP, design institutes and research organizations. This document takes stock on the situation and the research programs. (author)

  3. Circumferential resection margin (CRM) positivity after MRI assessment and adjuvant treatment in 189 patients undergoing rectal cancer resection.

    Science.gov (United States)

    Simpson, G S; Eardley, N; McNicol, F; Healey, P; Hughes, M; Rooney, P S

    2014-05-01

    The management of rectal cancer relies on accurate MRI staging. Multi-modal treatments can downstage rectal cancer prior to surgery and may have an effect on MRI accuracy. We aim to correlate the findings of MRI staging of rectal cancer with histological analysis, the effect of neoadjuvant therapy on this and the implications of circumferential resection margin (CRM) positivity following neoadjuvant therapy. An analysis of histological data and radiological staging of all cases of rectal cancer in a single centre between 2006 and 2011 were conducted. Two hundred forty-one patients had histologically proved rectal cancer during the study period. One hundred eighty-two patients underwent resection. Median age was 66.6 years, and male to female ratio was 13:5. R1 resection rate was 11.1%. MRI assessments of the circumferential resection margin in patients without neoadjuvant radiotherapy were 93.6 and 88.1% in patients who underwent neoadjuvant radiotherapy. Eighteen patients had predicted positive margins following chemoradiotherapy, of which 38.9% had an involved CRM on histological analysis. MRI assessment of the circumferential resection margin in rectal cancer is associated with high accuracy. Neoadjuvant chemoradiotherapy has a detrimental effect on this accuracy, although accuracy remains high. In the presence of persistently predicted positive margins, complete resection remains achievable but may necessitate a more radical approach to resection.

  4. TREATING UNCERTAINTIES IN A NUCLEAR SEISMIC PROBABILISTIC RISK ASSESSMENT BY MEANS OF THE DEMPSTER-SHAFER THEORY OF EVIDENCE

    OpenAIRE

    Lo , Chung-Kung; Pedroni , N.; Zio , Enrico

    2014-01-01

    International audience; The analyses carried out within the Seismic Probabilistic Risk Assessments (SPRAs) of Nuclear Power Plants (NPPs) are affected by significant aleatory and epistemic uncertainties. These uncertainties have to be represented and quantified coherently with the data, information and knowledge available, to provide reasonable assurance that related decisions can be taken robustly and with confidence. The amount of data, information and knowledge available for seismic risk a...

  5. RELIABILITY AND ACCURACY ASSESSMENT OF INVASIVE AND NON- INVASIVE SEISMIC METHODS FOR SITE CHARACTERIZATION: FEEDBACK FROM THE INTERPACIFIC PROJECT

    OpenAIRE

    Garofalo , F.; Foti , S.; Hollender , F.; Bard , P.-Y.; Cornou , C.; Cox , B.R.; Dechamp , A.; Ohrnberger , M.; Sicilia , D.; Vergniault , C.

    2017-01-01

    International audience; The InterPacific project (Intercomparison of methods for site parameter and velocity profile characterization) aims to assess the reliability of seismic site characterization methods (borehole and surface wave methods) used for estimating shear wave velocity (VS) profiles and other related parameters (e.g., VS30). Three sites, representative of different geological conditions relevant for the evaluation of seismic site response effects, have been selected: (1) a hard r...

  6. Probabilistic Seismic Risk Assessment in Manizales, Colombia:Quantifying Losses for Insurance Purposes

    Institute of Scientific and Technical Information of China (English)

    Mario A.Salgado-Gálvez; Gabriel A.Bernal; Daniela Zuloaga; Mabel C.Marulanda; Omar-Darío Cardona; Sebastián Henao

    2017-01-01

    A fully probabilistic seismic risk assessment was developed in Manizales,Colombia,considering assets of different types.The first type includes elements that are part of the water and sewage network,and the second type includes public and private buildings.This assessment required the development of a probabilistic seismic hazard analysis that accounts for the dynamic soil response,assembling high resolution exposure databases,and the development of damage models for different types of elements.The economic appraisal of the exposed assets was developed together with specialists of the water utilities company of Manizales and the city administration.The risk assessment was performed using several Comprehensive Approach to Probabilistic Risk Assessment modules as well as the R-System,obtaining results in terms of traditional metrics such as loss exceedance curve,average annual loss,and probable maximum loss.For the case of pipelines,repair rates were also estimated.The results for the water and sewage network were used in activities related to the expansion and maintenance strategies,as well as for the exploration of financial retention and transfer alternatives using insurance schemes based on technical,probabilistic,and prospective damage and loss estimations.In the case of the buildings,the results were used in the update of the technical premium values of the existing collective insurance scheme.

  7. Urban MEMS based seismic network for post-earthquakes rapid disaster assessment

    Science.gov (United States)

    D'Alessandro, Antonino; Luzio, Dario; D'Anna, Giuseppe

    2014-05-01

    Life losses following disastrous earthquake depends mainly by the building vulnerability, intensity of shaking and timeliness of rescue operations. In recent decades, the increase in population and industrial density has significantly increased the exposure to earthquakes of urban areas. The potential impact of a strong earthquake on a town center can be reduced by timely and correct actions of the emergency management centers. A real time urban seismic network can drastically reduce casualties immediately following a strong earthquake, by timely providing information about the distribution of the ground shaking level. Emergency management centers, with functions in the immediate post-earthquake period, could be use this information to allocate and prioritize resources to minimize loss of human life. However, due to the high charges of the seismological instrumentation, the realization of an urban seismic network, which may allow reducing the rate of fatalities, has not been achieved. Recent technological developments in MEMS (Micro Electro-Mechanical Systems) technology could allow today the realization of a high-density urban seismic network for post-earthquakes rapid disaster assessment, suitable for the earthquake effects mitigation. In the 1990s, MEMS accelerometers revolutionized the automotive-airbag system industry and are today widely used in laptops, games controllers and mobile phones. Due to their great commercial successes, the research into and development of MEMS accelerometers are actively pursued around the world. Nowadays, the sensitivity and dynamics of these sensors are such to allow accurate recording of earthquakes with moderate to strong magnitude. Due to their low cost and small size, the MEMS accelerometers may be employed for the realization of high-density seismic networks. The MEMS accelerometers could be installed inside sensitive places (high vulnerability and exposure), such as schools, hospitals, public buildings and places of

  8. Biomechanical Effect of Margin Convergence Techniques: Quantitative Assessment of Supraspinatus Muscle Stiffness.

    Directory of Open Access Journals (Sweden)

    Taku Hatta

    Full Text Available Although the margin convergence (MC technique has been recognized as an option for rotator cuff repair, little is known about the biomechanical effect on repaired rotator cuff muscle, especially after supplemented footprint repair. The purpose of this study was to assess the passive stiffness changes of the supraspinatus (SSP muscle after MC techniques using shear wave elastography (SWE. A 30 × 40-mm U-shaped rotator cuff tear was created in 8 cadaveric shoulders. Each specimen was repaired with 6 types of MC technique (1-, 2-, 3-suture MC with/without footprint repair, in a random order at 30° glenohumeral abduction. Passive stiffness of four anatomical regions in the SSP muscle was measured based on an established SWE method. Data were obtained from the SSP muscle at 0° abduction under 8 different conditions: intact (before making a tear, torn, and postoperative conditions with 6 techniques. MC techniques using 1-, or 2-suture combined with footprint repair showed significantly higher stiffness values than the intact condition. Passive stiffness of the SSP muscle was highest after a 1-suture MC with footprint repair for all regions when compared among all repair procedures. There was no significant difference between the intact condition and a 3-suture MC with footprint repair. MC techniques with single stitch and subsequent footprint repair may have adverse effects on muscle properties and tensile loading on repair, increasing the risk of retear of repairs. Adding more MC stitches could reverse these adverse effects.

  9. Validation of micro-CT against the section method regarding the assessment of marginal leakage of sealants.

    NARCIS (Netherlands)

    Chen, X.; Cuijpers, V.M.J.I.; Fan, M.W.; Frencken, J.E.F.M.

    2012-01-01

    BACKGROUND: The aim of this study was to validate the micro-CT and related software against the section method using the stereomicroscope for marginal leakage assessment along the sealant-enamel interface. METHODS: Pits and fissures of the occlusal surface of 10 teeth were sealed with a

  10. OVERVIEW ON BNL ASSESSMENT OF SEISMIC ANALYSIS METHODS FOR DEEPLY EMBEDDED NPP STRUCTURES

    International Nuclear Information System (INIS)

    XU, J.; COSTANTINO, C.; HOFMAYER, C.; GRAVES, H.

    2007-01-01

    A study was performed by Brookhaven National Laboratory (BNL) under the sponsorship of the U. S. Nuclear Regulatory Commission (USNRC), to determine the applicability of established soil-structure interaction analysis methods and computer programs to deeply embedded and/or buried (DEB) nuclear power plant (NPP) structures. This paper provides an overview of the BNL study including a description and discussions of analyses performed to assess relative performance of various SSI analysis methods typically applied to NPP structures, as well as the importance of interface modeling for DEB structures. There are four main elements contained in the BNL study: (1) Review and evaluation of existing seismic design practice, (2) Assessment of simplified vs. detailed methods for SSI in-structure response spectrum analysis of DEB structures, (3) Assessment of methods for computing seismic induced earth pressures on DEB structures, and (4) Development of the criteria for benchmark problems which could be used for validating computer programs for computing seismic responses of DEB NPP structures. The BNL study concluded that the equivalent linear SSI methods, including both simplified and detailed approaches, can be extended to DEB structures and produce acceptable SSI response calculations, provided that the SSI response induced by the ground motion is very much within the linear regime or the non-linear effect is not anticipated to control the SSI response parameters. The BNL study also revealed that the response calculation is sensitive to the modeling assumptions made for the soil/structure interface and application of a particular material model for the soil

  11. Margin benefit assessment of the YGN 3 cycle 1 fxy error files for COLSS and CPC overall uncertainty analyses

    International Nuclear Information System (INIS)

    Yoon, Rae Young; In, Wang Kee; Auh, Geun Sun; Kim, Hee Cheol; Lee, Sang Keun

    1994-01-01

    Margin benefits are quantitatively assessed for the Yonggwang Unit 3 (YGN 3) Cycle 1 planar radial peaking factor (Fxy) error files for each time-in-life, i.e., BOC, IOC, MOC and EOC. The generic Fxy error file (FXYMEQO) is presently used for Yonggwang Unit 3 Cycle 1 COLSS (Core Operating Limit Supervisory System) and CPC (Core Protection Calculator) Overall Uncertainty Analyses (OUA). However, because this file is more conservative than the plant/cycle specific Fxy error files, COLSS and CPC thermal margins (DNB-OPM) for the generic Fxy error file are less than those of the plant/cycle specific Fxy error file. Therefore, the YGN 3 Cycle 1 Fxy error files were generated and analyzed by the modified codes for Yonggwang Plants. The YGN 3 Cycle 1 Fxy error files gave the increased thermal margin by about 1% for COLSS and CPC, respectively

  12. Precursory groundwater level changes in the period of activation of the weak intraplate seismic activity on the NE margin of the Bohemian Massif (central Europe) in 2005

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Vladimír; Kašpárek, L.; Kopylova, Galina N.; Lyubushin, Alexei A.; Skalský, Lumír

    2009-01-01

    Roč. 53, č. 2 (2009), s. 215-238 ISSN 0039-3169 R&D Projects: GA ČR GA205/09/1244; GA ČR(CZ) GD205/05/H020 Institutional research plan: CEZ:AV0Z30460519; CEZ:AV0Z30120515 Keywords : seismic activity * earthquake precursors * groundwater Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.000, year: 2009

  13. Drift Reliability Assessment of a Four Storey Frame Residential Building Under Seismic Loading Considering Multiple Factors

    Science.gov (United States)

    Sil, Arjun; Longmailai, Thaihamdau

    2017-09-01

    The lateral displacement of Reinforced Concrete (RC) frame building during an earthquake has an important impact on the structural stability and integrity. However, seismic analysis and design of RC building needs more concern due to its complex behavior as the performance of the structure links to the features of the system having many influencing parameters and other inherent uncertainties. The reliability approach takes into account the factors and uncertainty in design influencing the performance or response of the structure in which the safety level or the probability of failure could be ascertained. This present study, aims to assess the reliability of seismic performance of a four storey residential RC building seismically located in Zone-V as per the code provisions given in the Indian Standards IS: 1893-2002. The reliability assessment performed by deriving an explicit expression for maximum roof-lateral displacement as a failure function by regression method. A total of 319, four storey RC buildings were analyzed by linear static method using SAP2000. However, the change in the lateral-roof displacement with the variation of the parameters (column dimension, beam dimension, grade of concrete, floor height and total weight of the structure) was observed. A generalized relation established by regression method which could be used to estimate the expected lateral displacement owing to those selected parameters. A comparison made between the displacements obtained from analysis with that of the equation so formed. However, it shows that the proposed relation could be used directly to determine the expected maximum lateral displacement. The data obtained from the statistical computations was then used to obtain the probability of failure and the reliability.

  14. Proceedings of the twenty-fourth water reactor safety information meeting. Volume 3: PRA and HRA; Probabilistic seismic hazard assessment and seismic siting criteria

    International Nuclear Information System (INIS)

    Monteleone, S.

    1997-02-01

    This three-volume report contains papers presented at the Twenty-Fourth Water Reactor Safety Information Meeting held at the Bethesda Marriott Hotel, Bethesda, Maryland, October 21--23, 1996. The papers are printed in the order of their presentation in each session and describe progress and results of programs in nuclear safety research conducted in this country and abroad. Foreign participation in the meeting included papers presented by researchers from Czech Republic, Finland, France, Japan, Norway, Russia and United Kingdom. This volume is divided into the following sections: PRA and HRA and probabilistic seismic hazard assessment and seismic siting criteria. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database

  15. Proceedings of the twenty-fourth water reactor safety information meeting. Volume 3: PRA and HRA; Probabilistic seismic hazard assessment and seismic siting criteria

    Energy Technology Data Exchange (ETDEWEB)

    Monteleone, S. [comp.] [Brookhaven National Lab., Upton, NY (United States)

    1997-02-01

    This three-volume report contains papers presented at the Twenty-Fourth Water Reactor Safety Information Meeting held at the Bethesda Marriott Hotel, Bethesda, Maryland, October 21--23, 1996. The papers are printed in the order of their presentation in each session and describe progress and results of programs in nuclear safety research conducted in this country and abroad. Foreign participation in the meeting included papers presented by researchers from Czech Republic, Finland, France, Japan, Norway, Russia and United Kingdom. This volume is divided into the following sections: PRA and HRA and probabilistic seismic hazard assessment and seismic siting criteria. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  16. Probabilistic seismic safety assessment of a CANDU 6 nuclear power plant including ambient vibration tests: Case study

    Energy Technology Data Exchange (ETDEWEB)

    Nour, Ali [Hydro Québec, Montréal, Québec H2L4P5 (Canada); École Polytechnique de Montréal, Montréal, Québec H3C3A7 (Canada); Cherfaoui, Abdelhalim; Gocevski, Vladimir [Hydro Québec, Montréal, Québec H2L4P5 (Canada); Léger, Pierre [École Polytechnique de Montréal, Montréal, Québec H3C3A7 (Canada)

    2016-08-01

    Highlights: • In this case study, the seismic PSA methodology adopted for a CANDU 6 is presented. • Ambient vibrations testing to calibrate a 3D FEM and to reduce uncertainties is performed. • Procedure for the development of FRS for the RB considering wave incoherency effect is proposed. • Seismic fragility analysis for the RB is presented. - Abstract: Following the 2011 Fukushima Daiichi nuclear accident in Japan there is a worldwide interest in reducing uncertainties in seismic safety assessment of existing nuclear power plant (NPP). Within the scope of a Canadian refurbishment project of a CANDU 6 (NPP) put in service in 1983, structures and equipment must sustain a new seismic demand characterised by the uniform hazard spectrum (UHS) obtained from a site specific study defined for a return period of 1/10,000 years. This UHS exhibits larger spectral ordinates in the high-frequency range than those used in design. To reduce modeling uncertainties as part of a seismic probabilistic safety assessment (PSA), Hydro-Québec developed a procedure using ambient vibrations testing to calibrate a detailed 3D finite element model (FEM) of the containment and reactor building (RB). This calibrated FE model is then used for generating floor response spectra (FRS) based on ground motion time histories compatible with the UHS. Seismic fragility analyses of the reactor building (RB) and structural components are also performed in the context of a case study. Because the RB is founded on a large circular raft, it is possible to consider the effect of the seismic wave incoherency to filter out the high-frequency content, mainly above 10 Hz, using the incoherency transfer function (ITF) method. This allows reducing significantly the non-necessary conservatism in resulting FRS, an important issue for an existing NPP. The proposed case study, and related methodology using ambient vibration testing, is particularly useful to engineers involved in seismic re-evaluation of

  17. Seismic evaluation of existing nuclear facilities. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    Programmes for re-evaluation and upgrading of safety of existing nuclear facilities are presently under way in a number of countries around the world. An important component of these programmes is the re-evaluation of the seismic safety through definition of new seismic parameters at the site and evaluation of seismic capacity of structures, equipment and distribution systems following updated information and criteria. The Seminar is intended to provide a forum for the exchange of information and discussion of the state-of-the-art on seismic safety of nuclear facilities in operation or under construction. Both analytical and experimental techniques for the evaluation of seismic capacity of structures, equipment and distribution systems are discussed. Full scale and field tests of structures and components using shaking tables, mechanical exciters, explosive and shock tests, and ambient vibrations are included in the seminar programme with emphasis on recent case histories. Presentations at the Seminar also include analytical techniques for the determination of dynamic properties of soil-structure systems from experiments as well as calibration of numerical models. Methods and criteria for seismic margin assessment based on experience data obtained from the behaviour of structures and components in real earthquakes are discussed. Guidelines for defining technical requirements for capacity re-evaluation (i.e. acceptable behaviour limits and design and implementation of structure and components upgrades are also presented and discussed. The following topics were covered during 7 sessions: earthquake experience and seismic re-evaluation; country experience in seismic re-evaluation programme; generic WWER studies; analytical methods for seismic capacity re-evaluation; experimental methods for seismic capacity re-evaluation; case studies.

  18. Seismic evaluation of existing nuclear facilities. Proceedings

    International Nuclear Information System (INIS)

    1995-01-01

    Programmes for re-evaluation and upgrading of safety of existing nuclear facilities are presently under way in a number of countries around the world. An important component of these programmes is the re-evaluation of the seismic safety through definition of new seismic parameters at the site and evaluation of seismic capacity of structures, equipment and distribution systems following updated information and criteria. The Seminar is intended to provide a forum for the exchange of information and discussion of the state-of-the-art on seismic safety of nuclear facilities in operation or under construction. Both analytical and experimental techniques for the evaluation of seismic capacity of structures, equipment and distribution systems are discussed. Full scale and field tests of structures and components using shaking tables, mechanical exciters, explosive and shock tests, and ambient vibrations are included in the seminar programme with emphasis on recent case histories. Presentations at the Seminar also include analytical techniques for the determination of dynamic properties of soil-structure systems from experiments as well as calibration of numerical models. Methods and criteria for seismic margin assessment based on experience data obtained from the behaviour of structures and components in real earthquakes are discussed. Guidelines for defining technical requirements for capacity re-evaluation (i.e. acceptable behaviour limits and design and implementation of structure and components upgrades are also presented and discussed. The following topics were covered during 7 sessions: earthquake experience and seismic re-evaluation; country experience in seismic re-evaluation programme; generic WWER studies; analytical methods for seismic capacity re-evaluation; experimental methods for seismic capacity re-evaluation; case studies

  19. Comparative risk assessment of carcinogens in alcoholic beverages using the margin of exposure approach.

    Science.gov (United States)

    Lachenmeier, Dirk W; Przybylski, Maria C; Rehm, Jürgen

    2012-09-15

    Alcoholic beverages have been classified as carcinogenic to humans. As alcoholic beverages are multicomponent mixtures containing several carcinogenic compounds, a quantitative approach is necessary to compare the risks. Fifteen known and suspected human carcinogens (acetaldehyde, acrylamide, aflatoxins, arsenic, benzene, cadmium, ethanol, ethyl carbamate, formaldehyde, furan, lead, 4-methylimidazole, N-nitrosodimethylamine, ochratoxin A and safrole) occurring in alcoholic beverages were identified based on monograph reviews by the International Agency for Research on Cancer. The margin of exposure (MOE) approach was used for comparative risk assessment. MOE compares a toxicological threshold with the exposure. MOEs above 10,000 are judged as low priority for risk management action. MOEs were calculated for different drinking scenarios (low risk and heavy drinking) and different levels of contamination for four beverage groups (beer, wine, spirits and unrecorded alcohol). The lowest MOEs were found for ethanol (3.1 for low risk and 0.8 for heavy drinking). Inorganic lead and arsenic have average MOEs between 10 and 300, followed by acetaldehyde, cadmium and ethyl carbamate between 1,000 and 10,000. All other compounds had average MOEs above 10,000 independent of beverage type. Ethanol was identified as the most important carcinogen in alcoholic beverages, with clear dose response. Some other compounds (lead, arsenic, ethyl carbamate, acetaldehyde) may pose risks below thresholds normally tolerated for food contaminants, but from a cost-effectiveness point of view, the focus should be on reducing alcohol consumption in general rather than on mitigative measures for some contaminants that contribute only to a limited extent (if at all) to the total health risk. Copyright © 2012 UICC.

  20. Structure of the lithosphere below the southern margin of the East European Craton (Ukraine and Russia) from gravity and seismic data.

    NARCIS (Netherlands)

    Yegorova, T.P.; Stephenson, R.A.; Kostyuchenko, S.L.; Baranova, E.P.; Starostenko, V.I.; Popolitov, K.E.

    2004-01-01

    The present study was undertaken with the objective of deriving constraints from available geological and geophysical data for understanding the tectonic setting and processes controlling the evolution of the southern margin of the East European Craton (EEC). The study area includes the inverted

  1. Damage Identification and Seismic Vulnerability Assessment of a Historic Masonry Chimney

    Directory of Open Access Journals (Sweden)

    Maria-Giovanna Masciotta

    2017-07-01

    Full Text Available The present paper deals with the dynamic characterisation of a historical masonry chimney aimed at identifying the structural damage and assessing its seismic performance. The structure was severely damaged by a lightning accident and in-depth repair works were executed to re-instate its sound configuration. The case study is fully detailed, including the aspects of survey, inspection, diagnosis, and evolution of the dynamic properties of the system throughout the structural intervention. Considering the explicit dependence of the power spectral densities of measured nodal processes on their frequency content, a spectrum-driven algorithm is used to detect and locate the damage. The paper shows that the eigenparameters obtained from the decomposition of the response power spectrum matrix are sensitive to system’s changes caused by evolutionary damage scenarios, thereby resulting excellent indicators for assessing both the presence and position of structural vulnerabilities. The results are compared with the ones from other modal-based damage identification methods and the strengths/limitations of the tools currently available in literature are extensively discussed. Finally, based on the crack pattern surveyed before the repair works, the weakest links of the chimney are identified and the most meaningful collapse mechanisms are analysed to verify the seismic capacity of the structure. According to the results of the kinematic analysis, the chimney does withstand the maximum site peak ground acceleration.

  2. A method to establish seismic noise baselines for automated station assessment

    Science.gov (United States)

    McNamara, D.E.; Hutt, C.R.; Gee, L.S.; Benz, H.M.; Buland, R.P.

    2009-01-01

    We present a method for quantifying station noise baselines and characterizing the spectral shape of out-of-nominal noise sources. Our intent is to automate this method in order to ensure that only the highest-quality data are used in rapid earthquake products at NEIC. In addition, the station noise baselines provide a valuable tool to support the quality control of GSN and ANSS backbone data and metadata. The procedures addressed here are currently in development at the NEIC, and work is underway to understand how quickly changes from nominal can be observed and used within the NEIC processing framework. The spectral methods and software used to compute station baselines and described herein (PQLX) can be useful to both permanent and portable seismic stations operators. Applications include: general seismic station and data quality control (QC), evaluation of instrument responses, assessment of near real-time communication system performance, characterization of site cultural noise conditions, and evaluation of sensor vault design, as well as assessment of gross network capabilities (McNamara et al. 2005). Future PQLX development plans include incorporating station baselines for automated QC methods and automating station status report generation and notification based on user-defined QC parameters. The PQLX software is available through the USGS (http://earthquake. usgs.gov/research/software/pqlx.php) and IRIS (http://www.iris.edu/software/ pqlx/).

  3. Seismic rupture modelling, strong motion prediction and seismic hazard assessment: fundamental and applied approaches; Modelisation de la rupture sismique, prediction du mouvement fort, et evaluation de l'alea sismique: approches fondamentale et appliquee

    Energy Technology Data Exchange (ETDEWEB)

    Berge-Thierry, C

    2007-05-15

    The defence to obtain the 'Habilitation a Diriger des Recherches' is a synthesis of the research work performed since the end of my Ph D. thesis in 1997. This synthesis covers the two years as post doctoral researcher at the Bureau d'Evaluation des Risques Sismiques at the Institut de Protection (BERSSIN), and the seven consecutive years as seismologist and head of the BERSSIN team. This work and the research project are presented in the framework of the seismic risk topic, and particularly with respect to the seismic hazard assessment. Seismic risk combines seismic hazard and vulnerability. Vulnerability combines the strength of building structures and the human and economical consequences in case of structural failure. Seismic hazard is usually defined in terms of plausible seismic motion (soil acceleration or velocity) in a site for a given time period. Either for the regulatory context or the structural specificity (conventional structure or high risk construction), seismic hazard assessment needs: to identify and locate the seismic sources (zones or faults), to characterize their activity, to evaluate the seismic motion to which the structure has to resist (including the site effects). I specialized in the field of numerical strong-motion prediction using high frequency seismic sources modelling and forming part of the IRSN allowed me to rapidly working on the different tasks of seismic hazard assessment. Thanks to the expertise practice and the participation to the regulation evolution (nuclear power plants, conventional and chemical structures), I have been able to work on empirical strong-motion prediction, including site effects. Specific questions related to the interface between seismologists and structural engineers are also presented, especially the quantification of uncertainties. This is part of the research work initiated to improve the selection of the input ground motion in designing or verifying the stability of structures. (author)

  4. Seismic rupture modelling, strong motion prediction and seismic hazard assessment: fundamental and applied approaches; Modelisation de la rupture sismique, prediction du mouvement fort, et evaluation de l'alea sismique: approches fondamentale et appliquee

    Energy Technology Data Exchange (ETDEWEB)

    Berge-Thierry, C

    2007-05-15

    The defence to obtain the 'Habilitation a Diriger des Recherches' is a synthesis of the research work performed since the end of my Ph D. thesis in 1997. This synthesis covers the two years as post doctoral researcher at the Bureau d'Evaluation des Risques Sismiques at the Institut de Protection (BERSSIN), and the seven consecutive years as seismologist and head of the BERSSIN team. This work and the research project are presented in the framework of the seismic risk topic, and particularly with respect to the seismic hazard assessment. Seismic risk combines seismic hazard and vulnerability. Vulnerability combines the strength of building structures and the human and economical consequences in case of structural failure. Seismic hazard is usually defined in terms of plausible seismic motion (soil acceleration or velocity) in a site for a given time period. Either for the regulatory context or the structural specificity (conventional structure or high risk construction), seismic hazard assessment needs: to identify and locate the seismic sources (zones or faults), to characterize their activity, to evaluate the seismic motion to which the structure has to resist (including the site effects). I specialized in the field of numerical strong-motion prediction using high frequency seismic sources modelling and forming part of the IRSN allowed me to rapidly working on the different tasks of seismic hazard assessment. Thanks to the expertise practice and the participation to the regulation evolution (nuclear power plants, conventional and chemical structures), I have been able to work on empirical strong-motion prediction, including site effects. Specific questions related to the interface between seismologists and structural engineers are also presented, especially the quantification of uncertainties. This is part of the research work initiated to improve the selection of the input ground motion in designing or verifying the stability of structures. (author)

  5. Methodology for the Assessment of Confidence in Safety Margin for Small Break Loss of Coolant Accident Sequences

    Energy Technology Data Exchange (ETDEWEB)

    Nagrale, D. B.; Prasad, M.; Rao, R. S.; Gaikwad, A.J., E-mail: avinashg@aerb.gov.in [Nuclear Safety Analysis Division, Atomic Energy Regulatory Board, Mumbai (India)

    2014-10-15

    Deterministic Safety Analysis and Probabilistic Safety Assessment (PSA) analyses are used concurrently to assess the Nuclear Power Plant (NPP) safety. The conventional deterministic analysis is conservative. The best estimate plus uncertainty analysis is increasingly being used for deterministic calculation in NPPs. The PSA methodology aims to be as realistic as possible while integrating information about accident phenomena, plant design, operating practices, component reliability and human behaviour. The peak clad temperature (PCT) distribution provides an insight into the confidence in safety margin for an initiating event. The paper deals with the concept of calculating the peak clad temperature with 95 percent confidence and 95 percent probability (PCT{sub 95/95}) in small break loss of coolant accident (SBLOCA) and methodologies for assessing safety margin. Five input parameters mainly, nominal power level, decay power, fuel clad gap conductivity, fuel thermal conductivity and discharge coefficient, were selected. A Uniform probability density function was assigned to the uncertain parameters and these uncertainties are propagated using Latin Hypercube Sampling (LHS) technique. The sampled data for 5 parameters were randomly mixed by LHS to obtain 25 input sets. A non-core damage accident sequence was selected from the SBLOCA event tree of a typical VVER study to estimate the PCTs and safety margin. A Kolmogorov– Smirnov goodness-of-fit test was carried out for PCTs. The smallest value of safety margin would indicate the robustness of the system with 95% confidence and 95% probability. Regression analysis was also carried out using 1000 sample size for the estimating PCTs. Mean, variance and finally safety margin were analysed. (author)

  6. Geologic aspects of seismic hazards assessment at the Idaho National Engineering Laboratory, southeastern Idaho

    International Nuclear Information System (INIS)

    Smith, R.P.; Hackett, W.R.; Rodgers, D.W.

    1989-01-01

    The Idaho National Engineering Laboratory (INEL), located on the northwestern side of the Eastern Snake River Plain (ESRP), lies in an area influenced by two distinct geologic provinces. The ESRP province is a northeast-trending zone of late Tertiary and Quaternary volcanism which transects the northwest-trending, block-fault mountain ranges of the Basin and Range province. An understanding of the interaction of these two provinces is important for realistic geologic hazards assessment. Of particular importance for seismic hazards analysis is the relationship of volcanic rift zones on the ESRP to basin-and-range faults north of the plain. The Arco Rift Zone, a 20-km-long belt of deformation and volcanism on the plain just west of the INEL, is colinear with the basin-and-range Lost River fault. Recent field studies have demonstrated that Arco Rift Zone deformation is typical of that induced by dike injection in other volcanic rift zones. The deformation is characterized by a predominance of dilational fissuring with less extensive development of faults and grabens. Cumulative vertical displacements over the past 0.6 Ma are an order of magnitude lower than those associated with the Arco Segment of the Lost River fault to the northwest. The evidence suggests that the northeast-directed extension that produces the block fault mountains of the Basin and Range is expressed by dike injection and volcanic rift zone development in the ESRP. Seismicity associated with dike injection during rift zone development is typically of low magnitude and would represent only minor hazard compared to that associated with the block faulting. Since the ESRP responds to extension in a manner distinct from basin-and-range faulting, it is not appropriate to consider the volcanic rift zones as extensions of basin-and-range faults for seismic hazard analysis

  7. Application of the Integrated Safety Assessment methodology to safety margins. Dynamic Event Trees, Damage Domains and Risk Assessment

    International Nuclear Information System (INIS)

    Ibánez, L.; Hortal, J.; Queral, C.; Gómez-Magán, J.; Sánchez-Perea, M.; Fernández, I.; Meléndez, E.; Expósito, A.; Izquierdo, J.M.; Gil, J.; Marrao, H.; Villalba-Jabonero, E.

    2016-01-01

    The Integrated Safety Assessment (ISA) methodology, developed by the Consejo de Seguridad Nuclear, has been applied to an analysis of Zion NPP for sequences with Loss of the Component Cooling Water System (CCWS). The ISA methodology proposal starts from the unfolding of the Dynamic Event Tree (DET). Results from this first step allow assessing the sequence delineation of standard Probabilistic Safety Analysis results. For some sequences of interest of the outlined DET, ISA then identifies the Damage Domain (DD). This is the region of uncertain times and/or parameters where a safety limit is exceeded, which indicates the occurrence of certain damage situation. This paper illustrates application of this concept obtained simulating sequences with MAAP and with TRACE. From information of simulation results of sequence transients belonging to the DD and the time-density probability distributions of the manual actions and of occurrence of stochastic phenomena, ISA integrates the dynamic reliability equations proposed to obtain the sequence contribution to the global Damage Exceedance Frequency (DEF). Reported results show a slight increase in the DEF for sequences investigated following a power uprate from 100% to 110%. This demonstrates the potential use of the method to help in the assessment of design modifications. - Highlights: • This paper illustrates an application of the ISA methodology to safety margins. • Dynamic Event Trees are useful tool for verifying the standard PSA Event Trees. • The ISA methodology takes into account the uncertainties in human action times. • The ISA methodology shows the Damage Exceedance Frequency increase in power uprates.

  8. Crustal structure and sedimentation history over the Alleppey platform, southwest continental margin of India: Constraints from multichannel seismic and gravity data

    Directory of Open Access Journals (Sweden)

    P. Unnikrishnan

    2018-03-01

    Full Text Available The Alleppey Platform is an important morphological feature located in the Kerala-Konkan basin off the southwest coast of India. In the present study, seismic reflection data available in the basin were used to understand the sedimentation history and also to carry out integrated gravity interpretation. Detailed seismic reflection data in the basin reveals that: (1 the Alleppey Platform is associated with a basement high in the west of its present-day geometry (as observed in the time-structure map of the Trap Top (K/T boundary, (2 the platform subsequently started developing during the Eocene period and attained the present geometry by the Miocene and, (3 both the Alleppey platform and the Vishnu fracture zone have had significant impact on the sedimentation patterns (as shown by the time-structure and the isochron maps of the major sedimentary horizons in the region. The 3-D sediment gravity effect computed from the sedimentary layer geometry was used to construct the crustal Bouguer anomaly map of the region. The 3-D gravity inversion of crustal Bouguer anomaly exhibits a Moho depression below the western border of the platform and a minor rise towards the east which then deepens again below the Indian shield. The 2-D gravity modelling across the Alleppey platform reveals the geometry of crustal extension, in which there are patches of thin and thick crust. The Vishnu Fracture Zone appears as a crustal-scale feature at the western boundary of the Alleppey platform. Based on the gravity model and the seismic reflection data, we suggest that the basement high to the west of the present day Alleppey platform remained as a piece of continental block very close to the mainland with the intervening depression filling up with sediments during the rifting. In order to place the Alleppey platform in the overall perspective of tectonic evolution of the Kerala-Konkan basin, we propose its candidature as a continental fragment.

  9. Evaluation of structural fragilities for an IPEEE seismic probabilistic risk assessment study

    International Nuclear Information System (INIS)

    Ghiocel, D.M.; Wilson, P.R.; Stevenson, J.D.

    1995-01-01

    The paper presents the main issues and results of a structural fragility analysis for a Seismic Probabilistic Risk Assessment (SPRA) study of a nuclear power plant (NPP) in the Eastern US. The fragility evaluations were performed for the Reactor Building, Auxiliary Building, Intake Structure and Diesel Generator Building. The random seismic input is defined in terms of the Uniform Hazard Spectrum (UHS) earthquake on the NPP site anchored to a reference level of 0.40 g Zero Period Ground Acceleration (ZPGA). Because of the soft soil conditions new Soil-Structure Interaction (SSI) analyses were performed using the original finite element (stick) structural models and the complex frequency approach. The soil deposit randomness was described by the variations in both the low strain soil shear modules and in its dependence with the shear strain. The probabilistic SSI analyses were performed using digital simulation techniques. The critical failure modes for each structure are investigated and the fragility evaluations are discussed. Concluding remarks and recommendations for improving the quality of the structural fragility analyses are included

  10. Assessment of Seismic Vulnerability of Steel and RC Moment Buildings Using HAZUS and Statistical Methodologies

    Directory of Open Access Journals (Sweden)

    Iman Mansouri

    2017-01-01

    Full Text Available Designer engineers have always the serious challenge regarding the choice of the kind of structures to use in the areas with significant seismic activities. Development of fragility curve provides an opportunity for designers to select a structure that will have the least fragility. This paper presents an investigation into the seismic vulnerability of both steel and reinforced concrete (RC moment frames using fragility curves obtained by HAZUS and statistical methodologies. Fragility curves are employed for several probability parameters. Fragility curves are used to assess several probability parameters. Furthermore, it examines whether the probability of the exceedence of the damage limit state is reduced as expected. Nonlinear dynamic analyses of five-, eight-, and twelve-story frames are carried out using Perform 3D. The definition of damage states is based on the descriptions provided by HAZUS, which gives the limit states and the associated interstory drift limits for structures. The fragility curves show that the HAZUS procedure reduces probability of damage, and this reduction is higher for RC frames. Generally, the RC frames have higher fragility compared to steel frames.

  11. Effect of Material Variability and Mechanical Eccentricity on the Seismic Vulnerability Assessment of Reinforced Concrete Buildings

    Directory of Open Access Journals (Sweden)

    Mario Lucio Puppio

    2017-07-01

    Full Text Available The present paper deals with the influence of material variability on the seismic vulnerability assessment of reinforced concrete buildings. Existing r.c. buildings are affected by a strong dispersion of material strengths of both the base materials. This influences the seismic response in linear and nonlinear static analysis. For this reason, it is useful to define a geometrical parameter called “material eccentricity”. As a reference model, an analysis of a two storey building is presented with a symmetrical plan but asymmetrical material distribution. Furthermore, an analysis of two real buildings with a similar issue is performed. Experimental data generate random material distributions to carry out a probabilistic analysis. By rotating the vector that defines the position of the center of strength it is possible to describe a strength domain that is characterized by equipotential lines in terms of the Risk Index. Material eccentricity is related to the Ultimate Shear of non-linear static analyses. This relevant uncertainty, referred to as the variation of the center of strength, is not considered in the current European and Italian Standards. The “material eccentricity” therefore reveals itself to be a relevant parameter to considering how material variability affects such a variation.

  12. Bayesian nonlinear structural FE model and seismic input identification for damage assessment of civil structures

    Science.gov (United States)

    Astroza, Rodrigo; Ebrahimian, Hamed; Li, Yong; Conte, Joel P.

    2017-09-01

    A methodology is proposed to update mechanics-based nonlinear finite element (FE) models of civil structures subjected to unknown input excitation. The approach allows to jointly estimate unknown time-invariant model parameters of a nonlinear FE model of the structure and the unknown time histories of input excitations using spatially-sparse output response measurements recorded during an earthquake event. The unscented Kalman filter, which circumvents the computation of FE response sensitivities with respect to the unknown model parameters and unknown input excitations by using a deterministic sampling approach, is employed as the estimation tool. The use of measurement data obtained from arrays of heterogeneous sensors, including accelerometers, displacement sensors, and strain gauges is investigated. Based on the estimated FE model parameters and input excitations, the updated nonlinear FE model can be interrogated to detect, localize, classify, and assess damage in the structure. Numerically simulated response data of a three-dimensional 4-story 2-by-1 bay steel frame structure with six unknown model parameters subjected to unknown bi-directional horizontal seismic excitation, and a three-dimensional 5-story 2-by-1 bay reinforced concrete frame structure with nine unknown model parameters subjected to unknown bi-directional horizontal seismic excitation are used to illustrate and validate the proposed methodology. The results of the validation studies show the excellent performance and robustness of the proposed algorithm to jointly estimate unknown FE model parameters and unknown input excitations.

  13. On the assessment of marginal life saving costs for risk acceptance criteria

    DEFF Research Database (Denmark)

    Fischer, Katharina; Virguez, Edgar; Sánchez-Silva, Mauricio

    2013-01-01

    : The definition of the marginal life saving costs, the discount rate used for comparing costs and benefits that accrue at different points in time and the time horizon over which future consequences of the decision are taken into account. In the present paper these issues are discussed based on a clear...

  14. Marginal leakage of two newer glass-ionomer-based sealant materials assessed using micro-CT.

    NARCIS (Netherlands)

    Chen, X.; Cuijpers, V.M.J.I.; Fan, M.; Frencken, J.E.F.M.

    2010-01-01

    OBJECTIVES: To test newer glass-ionomer-based materials as sealant materials. One glass-ionomer sealant was light-cured to obtain an early setting reaction. The null-hypothesis tested was: there is no difference in marginal leakage of sealants produced with high-viscosity glass-ionomer, with and

  15. Using Logistic Approximations of Marginal Trace Lines to Develop Short Assessments

    Science.gov (United States)

    Stucky, Brian D.; Thissen, David; Edelen, Maria Orlando

    2013-01-01

    Test developers often need to create unidimensional scales from multidimensional data. For item analysis, "marginal trace lines" capture the relation with the general dimension while accounting for nuisance dimensions and may prove to be a useful technique for creating short-form tests. This article describes the computations needed to obtain…

  16. Assessment of Marginal Adaptation and Sealing Ability of Root Canal Sealers: An in vitro Study.

    Science.gov (United States)

    Remy, Vimal; Krishnan, Vineesh; Job, Tisson V; Ravisankar, Madhavankutty S; Raj, C V Renjith; John, Seena

    2017-12-01

    This study aims to compare the marginal adaptation and sealing ability [mineral trioxide aggregate (MTA)-Fillapex, AH Plus, Endofill sealers] of root canal sealers. In the present study, the inclusion criteria include 45 single-rooted extracted mandibular premolar teeth, with single canal and complete root formation. The sectioning of the samples was done at the cementoenamel junction using a low-speed diamond disc. Step-back technique was used to prepare root canals manually. The MTA-Fillapex, AH Plus, and Endofill sealers were the three experimental sealer groups to which 45 teeth were distributed. Under scanning electron microscope (SEM), marginal gap at sealer and root dentin interface were examined at coronal and apical halves of root canal. Among the three maximum marginal adaptations were seen with AH Plus sealer (4.10 ± 0.10) which is followed by Endofill sealer (1.44 ± 0.18) and MTA-Fillapex sealer (0.80 ± 0.22). Between the coronal and apical marginal adaptation, significant statistical difference (p = 0.001) was seen in AH Plus sealer. When a Mann-Whitney U-test was done on MTA-Fillapex sealer vs AH Plus sealer and AH Plus sealer vs Endofill sealer, there was a statistically significant difference (p marginal adaptation when compared with other sealers used. For sealing space of crown wall and main cone in root canal treatment, sealers play an important role. The other advantages of sealers are that they are used to fill voids and irregularities in root channel, secondary, lateral channels, and space between applied gutta-percha cones and also act as tripper during filling.

  17. Assessment of margins in resection specimens for head and neck malignancies.

    Science.gov (United States)

    Janjua, Omer Sefvan; Ahmed, Waseem; Qureshi, Sana Mehmood; Khan, Tariq Sarfaraz; Ahmed, Ashfaq; Alamgir, Wajiha

    2013-04-01

    To determine the relative frequency of clear, close and involved margins in resection specimens for head and neck malignancies. An observational study. The Department of Oral and Maxillofacial Surgery, Armed Forces Institute of Dentistry, Rawalpindi and the Department of Histopathology, Armed Forces Institute of Pathology, Rawalpindi, from January 2008 to December 2010. Tumour registers and computer data bases in the department of Histopathology of Armed Forces Institute of Pathology, Rawalpindi, were analyzed for the cases of malignancies involving head and neck region that were sent for histopathological analysis after resection in the last three years. Histopathology reports were obtained. The data regarding age, gender, site, type of malignancy and margin status (clear, close or involved) was recorded on specially designed proformas for the study and later on analyzed by using SPSS version 17.0. Results were expressed. A total of 319 cases were registered in the study duration. The age of the patients ranged from 22-90 years (mean 59.5 + 14.1 years). Male to female ratio was 1.53:1. One hundred and thirty six (42.6%) were squamous cell carcinoma (SCC), 163 were basal cell carcinomas (BCC, 51.0%); the rest included 18 salivary gland malignancies (5.7%) and one carcino-sarcoma (0.31%) and chondrosarcoma each. All margins were found clear in 137 patients (42.9%); involved in 168 cases (52.7%) and close in 14 cases (4.4%). Margin clearance could not be achieved in more than 50% cases, this can lead to poor prognosis. Hence, methods should be adopted to improve the margin clearance in various head and neck malignancies.

  18. Assessment of margins in resection specimens for head and neck malignancies

    International Nuclear Information System (INIS)

    Janjua, O. S.; Ahmed, W.; Ahmed, A.; Qureshi, S. M.; Khan, T. S.; Alamgir, W.

    2013-01-01

    Objective: To determine the relative frequency of clear, close and involved margins in resection specimens for head and neck malignancies. Study Design: An observational study. Place and Duration of Study: The Department of Oral and Maxillofacial Surgery, Armed Forces Institute of Dentistry, Rawalpindi and the Department of Histopathology, Armed Forces Institute of Pathology, Rawalpindi, from January 2008 to December 2010. Methodology: Tumour registers and computer data bases in the department of Histopathology of Armed Forces Institute of Pathology, Rawalpindi, were analyzed for the cases of malignancies involving head and neck region that were sent for histopathological analysis after resection in the last three years. Histopathology reports were obtained. The data regarding age, gender, site, type of malignancy and margin status (clear, close or involved) was recorded on specially designed proformas for the study and later on analyzed by using SPSS version 17.0. Results were expressed. Results: A total of 319 cases were registered in the study duration. The age of the patients ranged from 22 - 90 years (mean 59.5 + 14.1 years). Male to female ratio was 1.53:1. One hundred and thirty six (42.6%) were squamous cell carcinoma (SCC), 163 were basal cell carcinomas (BCC, 51.0%); the rest included 18 salivary gland malignancies (5.7%) and one carcino-sarcoma (0.31%) and chondrosarcoma each. All margins were found clear in 137 patients (42.9%); involved in 168 cases (52.7%) and close in 14 cases (4.4%). Conclusion: Margin clearance could not be achieved in more than 50% cases, this can lead to poor prognosis. Hence, methods should be adopted to improve the margin clearance in various head and neck malignancies. (author)

  19. From Seismic Scenarios to Earthquake Risk Assessment: A Case Study for Iquique, Chile.

    Science.gov (United States)

    Aguirre, P.; Fortuno, C.; Martin, J. C. D. L. L.; Vasquez, J.

    2015-12-01

    Iquique is a strategic city and economic center in northern Chile, and is located in a large seismic gap where a megathrust earthquake and tsunami is expected. Although it was hit by a Mw 8.2 earthquake on April 1st 2014, which caused moderate damage, geophysical evidence still suggests that there is potential for a larger event, so a thorough risk assessment is key to understand the physical, social, and economic effects of such potential event, and devise appropriate mitigation plans. Hence, Iquique has been selected as a prime study case for the implementation of a risk assessment platform in Chile. Our study integrates research on three main elements of risk calculations: hazard evaluation, exposure model, and physical vulnerabilities. To characterize the hazard field, a set of synthetic seismic scenarios have been developed based on plate interlocking and the residual slip potential that results from subtracting the slip occurred during the April 1st 2014 rupture fault mechanism, obtained using InSAR+GPS inversion. Additional scenarios were developed based of the fault rupture model of the Maule 2010 Mw 8.8 earthquake and on the local plate locking models in northern Chile. These rupture models define a collection of possible realizations of earthquake geometries parameterized in terms of critical variables like slip magnitude, rise time, mean propagation velocity, directivity, and other, which are propagated to obtain a hazard map for Iquique (e.g. PGA, PGV, PDG). Furthermore, a large body of public and local data was used to construct a detailed exposure model for Iquique, including aggregated building count, demographics, essential facilities, and lifelines. This model together with the PGA maps for the April 1st 2014 earthquake are used to calibrate HAZUS outputs against observed damage, and adjust the fragility curves of physical systems according to more detailed analyses of typical Chilean building types and their structural properties, plus historical

  20. Hormesis: from marginalization to mainstream A case for hormesis as the default dose-response model in risk assessment

    International Nuclear Information System (INIS)

    Calabrese, Edward J.

    2004-01-01

    The paper provides an account of how the hormetic dose response has emerged in recent years as a serious dose-response model in toxicology and risk assessment after decades of extreme marginalization. In addition to providing the toxicological basis of this dose-response revival, the paper reexamines the concept of a default dose model in toxicology and risk assessment and makes the argument that the hormetic model satisfies criteria (e.g., generalizability, frequency, application to risk assessment endpoints, false positive/negative potential, requirements for hazard assessment, reliability of estimating risks, capacity for validation of risk estimates, public health implications of risk estimates) for such a default model better than its chief competitors, the threshold and linear at low dose models. The selection of the hormetic model as the default model in risk assessment for noncarcinogens and specifically for carcinogens would have a profound impact on the practice of risk assessment and its societal implications

  1. OpenQuake, a platform for collaborative seismic hazard and risk assessment

    Science.gov (United States)

    Henshaw, Paul; Burton, Christopher; Butler, Lars; Crowley, Helen; Danciu, Laurentiu; Nastasi, Matteo; Monelli, Damiano; Pagani, Marco; Panzeri, Luigi; Simionato, Michele; Silva, Vitor; Vallarelli, Giuseppe; Weatherill, Graeme; Wyss, Ben

    2013-04-01

    Sharing of data and risk information, best practices, and approaches across the globe is key to assessing risk more effectively. Through global projects, open-source IT development and collaborations with more than 10 regions, leading experts are collaboratively developing unique global datasets, best practice, tools and models for global seismic hazard and risk assessment, within the context of the Global Earthquake Model (GEM). Guided by the needs and experiences of governments, companies and international organisations, all contributions are being integrated into OpenQuake: a web-based platform that - together with other resources - will become accessible in 2014. With OpenQuake, stakeholders worldwide will be able to calculate, visualize and investigate earthquake hazard and risk, capture new data and share findings for joint learning. The platform is envisaged as a collaborative hub for earthquake risk assessment, used at global and local scales, around which an active network of users has formed. OpenQuake will comprise both online and offline tools, many of which can also be used independently. One of the first steps in OpenQuake development was the creation of open-source software for advanced seismic hazard and risk calculations at any scale, the OpenQuake Engine. Although in continuous development, a command-line version of the software is already being test-driven and used by hundreds worldwide; from non-profits in Central Asia, seismologists in sub-Saharan Africa and companies in South Asia to the European seismic hazard harmonization programme (SHARE). In addition, several technical trainings were organized with scientists from different regions of the world (sub-Saharan Africa, Central Asia, Asia-Pacific) to introduce the engine and other OpenQuake tools to the community, something that will continue to happen over the coming years. Other tools that are being developed of direct interest to the hazard community are: • OpenQuake Modeller; fundamental

  2. Geoethical and socio-political aspects of seismic and tsunami hazard assessment, quantification and mapping

    Science.gov (United States)

    Tinti, Stefano; Armigliato, Alberto

    2016-04-01

    Seismic hazard and, more recently, tsunami hazard assessments have been undertaken in several countries of the world and globally for the whole Earth planet with the aim of providing a scientifically sound basis to the engineers, technicians, urban and industrial planners, politicians, civil protection operators and in general to the authorities for devising rational risk mitigation strategies and corresponding adequate policies. The main point of this presentation is that the chief-value of all seismic and tsunami hazard studies (including theory, concept, quantification and mapping) resides in the social and political values of the provided products, which is a standpoint entailing a number of relevant geoethical implications. The most relevant implication regards geoscientists who are the subjects mainly involved in carrying out hazard evaluations. Viewed from the classical perspective, the main ethical obligations of geoscientists are restricted to performing hazard estimations in the best possible way from a scientific point of view, which means selecting the "best" available data, adopting sound theoretical models, making use of rigorous methods… What is outlined here, is that this is an insufficient minimalistic position, since it overlooks the basic socio-political and therefore practical value of the hazard-analysis final products. In other words, if one views hazard assessment as a production process leading from data and theories (raw data and production means) to hazard maps (products), the criterion to judge whether it is good or bad needs also to include the usability factor. Seismic and tsunami hazard reports and maps are products that should be usable, which means that they should meet user needs and requirements, and therefore they should be evaluated according to how much they are clearly understandable to, and appropriate for, making-decision users. In the traditional view of a science serving the society, one could represent the interaction

  3. Assessment of ablative margin after radiofrequency ablation for hepatocellular carcinoma; comparison between magnetic resonance imaging with ferucarbotran and enhanced CT with iodized oil deposition

    International Nuclear Information System (INIS)

    Koda, Masahiko; Tokunaga, Shiho; Fujise, Yuki; Kato, Jun; Matono, Tomomitsu; Sugihara, Takaaki; Nagahara, Takakazu; Ueki, Masaru; Murawaki, Yoshikazu; Kakite, Suguru; Yamashita, Eijiro

    2012-01-01

    Background and purpose: Our aim was to investigate whether magnetic resonance imaging (MRI) with ferucarbotran administered prior to radiofrequency ablation could accurately assess ablative margin when compared with enhanced computed tomography (CT) with iodized oil marking. Materials and methods: We enrolled 27 patients with 32 hepatocellular carcinomas in which iodized oil deposits were visible throughout the nodule after transcatheter arterial chemoembolization. For these nodules, radiofrequency ablation was performed after ferucarbotran administration. We then performed T2-weighted MRI after 1 week and enhanced CT after 1 month. T2-weighted MRI demonstrated the ablative margin as a low-intensity rim. We classified the margin into three grades; margin (+): high-intensity area with a continuous low-intensity rim; margin zero: high-intensity area with a discontinuous low-intensity rim; and margin (−): high-intensity area extending beyond the low-intensity rim. Results: In 28 (86%) of 32 nodules, there was agreement between MRI and CT. The overall agreement between for the two modalities in the assessment of ablative margin was good (κ = 0.759, 95% confidence interval: 0.480–1.000, p < 0.001). In four nodules, ablative margins on MRI were underestimated by one grade compared with CT. Conclusion: MRI using ferucarbotran is less invasive and allows earlier assessment than CT. The MRI technique performed similarly to enhanced CT with iodized oil marking in evaluating the ablative margin after radiofrequency ablation.

  4. Account for uncertainties of control measurements in the assessment of design margin factors

    International Nuclear Information System (INIS)

    Dementiev, V. G.; Sidorenko, V. D.; Shishkov, L. K.

    2011-01-01

    The paper discusses the feasibility of accounting for uncertainties of control measurements in estimation of design margin factors. The feasibility is also taken into consideration proceeding from the fact how much the processed measured data were corrected by a priori calculated data of measurable parameters. The possibility and feasibility of such data correction is demonstrated by the authors with the help of Bayes theorem famous in mathematical statistics. (Authors)

  5. Urban seismic risk assessment: statistical repair cost data and probable structural losses based on damage scenario—correlation analysis

    Science.gov (United States)

    Eleftheriadou, Anastasia K.; Baltzopoulou, Aikaterini D.; Karabinis, Athanasios I.

    2016-06-01

    The current seismic risk assessment is based on two discrete approaches, actual and probable, validating afterwards the produced results. In the first part of this research, the seismic risk is evaluated from the available data regarding the mean statistical repair/strengthening or replacement cost for the total number of damaged structures (180,427 buildings) after the 7/9/1999 Parnitha (Athens) earthquake. The actual evaluated seismic risk is afterwards compared to the estimated probable structural losses, which is presented in the second part of the paper, based on a damage scenario in the referring earthquake. The applied damage scenario is based on recently developed damage probability matrices (DPMs) from Athens (Greece) damage database. The seismic risk estimation refers to 750,085 buildings situated in the extended urban region of Athens. The building exposure is categorized in five typical structural types and represents 18.80 % of the entire building stock in Greece. The last information is provided by the National Statistics Service of Greece (NSSG) according to the 2000-2001 census. The seismic input is characterized by the ratio, a g/ a o, where a g is the regional peak ground acceleration (PGA) which is evaluated from the earlier estimated research macroseismic intensities, and a o is the PGA according to the hazard map of the 2003 Greek Seismic Code. Finally, the collected investigated financial data derived from different National Services responsible for the post-earthquake crisis management concerning the repair/strengthening or replacement costs or other categories of costs for the rehabilitation of earthquake victims (construction and function of settlements for earthquake homeless, rent supports, demolitions, shorings) are used to determine the final total seismic risk factor.

  6. Risk based seismic design criteria

    International Nuclear Information System (INIS)

    Kennedy, R.P.

    1999-01-01

    In order to develop a risk based seismic design criteria the following four issues must be addressed: (1) What target annual probability of seismic induced unacceptable performance is acceptable? (2) What minimum seismic margin is acceptable? (3) Given the decisions made under Issues 1 and 2, at what annual frequency of exceedance should the safe-shutdown-earthquake (SSE) ground motion be defined? (4) What seismic design criteria should be established to reasonably achieve the seismic margin defined under Issue 2? The first issue is purely a policy decision and is not addressed in this paper. Each of the other three issues are addressed. Issues 2 and 3 are integrally tied together so that a very large number of possible combinations of responses to these two issues can be used to achieve the target goal defined under Issue 1. Section 2 lays out a combined approach to these two issues and presents three potentially attractive combined resolutions of these two issues which reasonably achieves the target goal. The remainder of the paper discusses an approach which can be used to develop seismic design criteria aimed at achieving the desired seismic margin defined in resolution of Issue 2. Suggestions for revising existing seismic design criteria to more consistently achieve the desired seismic margin are presented. (orig.)

  7. Assessing the small-strain soil stiffness for offshore wind turbines based on in situ seismic measurements

    NARCIS (Netherlands)

    Versteijlen, W.G.; Van Dalen, K.N.; Metrikine, A.; Hamre, L.

    2014-01-01

    In this contribution, in situ seismic measurements are used to derive the small-strain shear modulus of soil as input for two soil-structure interaction (SSI) models to assess the initial soil stiffness for offshore wind turbine foundations. This stiffness has a defining influence on the first

  8. Assessment of effectiveness of anti-seismic measures in stabilization project of ChNPP shelter object

    International Nuclear Information System (INIS)

    Kondrat'ev, S.N.; Kritskij, V.B.; Ryzhov, D.I.; Shugajlo, A.P.; Shugajlo, Al.P.; Prabkhakara, M.

    2004-01-01

    The major factors, which may lead to the collapse of the Shelter object (SO) civil structures, are extreme natural phenomena and among them earthquake. In order to raise the resistance of the SO civil structure to seismic and other significant loads and to reduce the risk of their collapse ChNPP requested KSK Consortium to develop the SO Detailed Design for stabilization. At the present work the results of assessment of anti-seismic measures are given based on results of a technical review of the Detailed Design

  9. Coordinated experimental/analytical program for investigating margins to failure of Category I reinforced concrete structures

    International Nuclear Information System (INIS)

    Endebrock, E.; Dove, R.; Anderson, C.A.

    1981-01-01

    The material presented in this paper deals with a coordinated experimental/analytical program designed to provide information needed for making margins to failure assessments of seismic Category I reinforced concrete structures. The experimental program is emphasized and background information that lead to this particular experimental approach is presented. Analytical tools being developed to supplement the experimental program are discussed. 16 figures

  10. Seismic Performance Assessment and Strengthening of a Multi-Story RC Building through a Case Study of “Seaside Hotel”

    OpenAIRE

    Rasol, Mezgeen Abdulrahman

    2014-01-01

    ABSTRACT: In recent years great developments have been made in the assessment of existing buildings and their performance in resistance to earthquake loading, potential seismic risk, vulnerability and lateral loads. Existing buildings can be repaired and strengthened to include new developments and methods to resist earthquake and seismic loads, which is the most economical way to safeguard against the economic and social catastrophe affected by severe seismic activity in urban environments. ...

  11. Proposed Construction of Boulder Seismic Station Monitoring Sites, Boulder, Wyoming. Environmental Assessment

    Science.gov (United States)

    2009-02-01

    boreholes at the Boulder Seismic Station for research, development, test, and evaluation (RDT&E) as part of the U.S. Nuclear Treaty monitoring...14 LIST OF FIGURES Figure 1. Location of the proposed Boulder Seismic Station, borehole locations and associated buffers...juncture of Spring Creek and Scab Creek Road (Figure 1). Currently, the Boulder Seismic Station has a 13-element array of seismometers on the property

  12. Development of a seismic source model for probabilistic seismic hazard assessment of nuclear power plant sites in Switzerland: the view from PEGASOS Expert Group 4 (EG1d)

    International Nuclear Information System (INIS)

    Wiemer, S.; Garcia-Fernandez, M.; Burg, J.-P.

    2009-01-01

    We present a seismogenic source model for site-specific probabilistic seismic hazard assessment at the sites of Swiss nuclear power plants. Our model is one of four developed in the framework of the PEGASOS project; it contains a logic tree with nine levels of decision-making. The two primary sources of input used in the areal zonation developed by us are the historical and instrumental seismicity record and large-scale geological/rheological units. From this, we develop a zonation of six macro zones, refined in a series of seven decision steps up to a maximum of 13 zones. Within zones, activity rates are either assumed homogeneous or smoothed using a Gaussian kernel with width of 5 or 15 km. To estimate recurrence rate, we assume a double truncated Gutenberg-Richter law, and consider five models of recurrence parameters with different degrees of freedom. Models are weighted in the logic tree using a weighted Akaike score. The maximum magnitude is estimated following the EPRI approach. We perform extensive sensitivity analyses in rate and hazard space in order to assess the role of de-clustering, the completeness model, quarry contamination, border properties, stationarity, regional b-value and magnitude-dependent hypocentral depth. (author)

  13. Development of a seismic source model for probabilistic seismic hazard assessment of nuclear power plant sites in Switzerland: the view from PEGASOS Expert Group 4 (EG1d)

    Energy Technology Data Exchange (ETDEWEB)

    Wiemer, S. [Institute of Geophysics, ETH Zuerich, Zuerich (Switzerland); Garcia-Fernandez, M. [Spanish Council for Scientific Research, Museum of Natural History, Dept. of Volcanology and Geophysics, Madrid (Spain); Burg, J.-P. [Institute of Geology, ETH Zuerich, Zuerich (Switzerland)

    2009-05-15

    We present a seismogenic source model for site-specific probabilistic seismic hazard assessment at the sites of Swiss nuclear power plants. Our model is one of four developed in the framework of the PEGASOS project; it contains a logic tree with nine levels of decision-making. The two primary sources of input used in the areal zonation developed by us are the historical and instrumental seismicity record and large-scale geological/rheological units. From this, we develop a zonation of six macro zones, refined in a series of seven decision steps up to a maximum of 13 zones. Within zones, activity rates are either assumed homogeneous or smoothed using a Gaussian kernel with width of 5 or 15 km. To estimate recurrence rate, we assume a double truncated Gutenberg-Richter law, and consider five models of recurrence parameters with different degrees of freedom. Models are weighted in the logic tree using a weighted Akaike score. The maximum magnitude is estimated following the EPRI approach. We perform extensive sensitivity analyses in rate and hazard space in order to assess the role of de-clustering, the completeness model, quarry contamination, border properties, stationarity, regional b-value and magnitude-dependent hypocentral depth. (author)

  14. Portable optical fiber probe-based spectroscopic scanner for rapid cancer diagnosis: a new tool for intraoperative margin assessment.

    Directory of Open Access Journals (Sweden)

    Niyom Lue

    Full Text Available There continues to be a significant clinical need for rapid and reliable intraoperative margin assessment during cancer surgery. Here we describe a portable, quantitative, optical fiber probe-based, spectroscopic tissue scanner designed for intraoperative diagnostic imaging of surgical margins, which we tested in a proof of concept study in human tissue for breast cancer diagnosis. The tissue scanner combines both diffuse reflectance spectroscopy (DRS and intrinsic fluorescence spectroscopy (IFS, and has hyperspectral imaging capability, acquiring full DRS and IFS spectra for each scanned image pixel. Modeling of the DRS and IFS spectra yields quantitative parameters that reflect the metabolic, biochemical and morphological state of tissue, which are translated into disease diagnosis. The tissue scanner has high spatial resolution (0.25 mm over a wide field of view (10 cm × 10 cm, and both high spectral resolution (2 nm and high spectral contrast, readily distinguishing tissues with widely varying optical properties (bone, skeletal muscle, fat and connective tissue. Tissue-simulating phantom experiments confirm that the tissue scanner can quantitatively measure spectral parameters, such as hemoglobin concentration, in a physiologically relevant range with a high degree of accuracy (<5% error. Finally, studies using human breast tissues showed that the tissue scanner can detect small foci of breast cancer in a background of normal breast tissue. This tissue scanner is simpler in design, images a larger field of view at higher resolution and provides a more physically meaningful tissue diagnosis than other spectroscopic imaging systems currently reported in literatures. We believe this spectroscopic tissue scanner can provide real-time, comprehensive diagnostic imaging of surgical margins in excised tissues, overcoming the sampling limitation in current histopathology margin assessment. As such it is a significant step in the development of a

  15. Recent developments in seismic analysis in the code Aster

    International Nuclear Information System (INIS)

    Guihot, P.; Devesa, G.; Dumond, A.; Panet, M.; Waeckel, F.

    1996-01-01

    Progress in the field of seismic qualification and design methods made these last few years allows physical phenomena actually in play to be better considered, while cutting down the conservatism associated with some simplified design methods. So following the change in methods and developing the most advantageous ones among them contributes to the process of the seismic margins assessment and the preparation of new design tools for future series. In this paper, the main developments and improvements in methods which have been made these last two years in the Code Aster, in order to improve seismic calculation methods and seismic margin assessment are presented. The first development relates to making the MISS3D soil structure interaction code available, thanks to an interface made with the Code Aster. The second relates to the possibility of making modal basis time calculations on multi-supported structures by considering local non linearities like impact, friction or squeeze fluid forces. Recent developments in random dynamics and postprocessing devoted to earthquake designs are then mentioned. Three applications of these developments are then ut forward. The first application relates to a test case for soil structure interaction design using MISS3D-Aster coupling. The second is a test case for a multi-supported structure. The last application, more for manufacturing, refers to seismic qualification of Main Live Steam stop valves. First results of the independent validation of the Code Aster seismic design functionalities, which provide and improve the quality of software, are also recalled. (authors)

  16. A new discrete-element approach for the assessment of the seismic resistance of composite reinforced concrete-masonry buildings

    International Nuclear Information System (INIS)

    Calio, I.; Cannizzaro, F.; Marletta, M.; Panto, B.; D'Amore, E.

    2008-01-01

    In the present study a new discrete-element approach for the evaluation of the seismic resistance of composite reinforced concrete-masonry structures is presented. In the proposed model, unreinforced masonry panels are modelled by means of two-dimensional discrete-elements, conceived by the authors for modelling masonry structures, whereas the reinforced concrete elements are modelled by lumped plasticity elements interacting with the masonry panels through nonlinear interface elements. The proposed procedure was adopted for the assessment of the seismic response of a case study confined-masonry building which was conceived to be a typical representative of a wide class of residential buildings designed to the requirements of the 1909 issue of the Italian seismic code and widely adopted in the aftermath of the 1908 earthquake for the reconstruction of the cities of Messina and Reggio Calabria

  17. 3. General principles of assessing seismic resistance of technological equipment of nuclear power plants

    International Nuclear Information System (INIS)

    1983-01-01

    The evaluation of the seismic resistance of technological equipment is performed by computation, experimental trial, possibly by combining both methods. Existing and prepared standards in the field of seismic resistance of nuclear power plants are mentioned. Accelerograms and response spectra of design-basis earhtquake and maximum credible earthquake serve as the basic data for evaluating seismic resistance. The nuclear power plant in Mochovce will be the first Czechoslovak nuclear power plant with so-called partially seismic design. The problem of dynamic interaction of technological equipment and nuclear power plant systems with a bearing structure is discussed. (E.F.)

  18. Assessment of rock mechanical properties and seismic slope stability in variably weathered layered basalts

    Science.gov (United States)

    Greenwood, William; Clark, Marin; Zekkos, Dimitrios; Von Voigtlander, Jennifer; Bateman, Julie; Lowe, Katherine; Hirose, Mitsuhito; Anderson, Suzanne; Anderson, Robert; Lynch, Jerome

    2016-04-01

    A field and laboratory experimental study was conducted to assess the influence of weathering on the mechanical properties of basalts in the region of the Kohala volcano on the island of Hawaii. Through the systematic characterization of the weathering profiles developed in different precipitation regimes, we aim to explain the regional pattern of stability of slopes in layered basalts that were observed during the 2006 Mw 6.7 Kiholo Bay earthquake. While deeper weathering profiles on the wet side of the island might be expected to promote more and larger landslides, the distribution of landslides during the Kiholo Bay earthquake did not follow this anticipated trend. Landslide frequency (defined as number of landslides divided by total area) was similar on the steepest slopes (> 50-60) for both the dry and the wet side of the study area suggesting relatively strong ground materials irrespective of weathering. The study location is ideally suited to investigate the role of precipitation, and more broadly of climate, on the mechanical properties of the local rock units because the presence of the Kohala volcano produces a significant precipitation gradient on what are essentially identical basaltic flows. Mean annual precipitation (MAP) varies by more than an order of magnitude, from 200 mm/year on the western side of the volcano to 4000 mm/year in the eastern side. We will present results of measured shear wave velocities using a seismic surface wave methodology. These results were paired with laboratory testing on selected basalt specimens that document the sample-scale shear wave velocity and unconfined compressive strength of the basaltic rocks. Shear wave velocity and unconfined strength of the rocks are correlated and are both significantly lower in weathered rocks near the ground surface than at depth. This weathering-related reduction in shear wave velocity extends to greater depths in areas of high precipitation compared to areas of lower precipitation

  19. Some considerations for establishing seismic</