WorldWideScience

Sample records for seismic effects

  1. Seismic effects on underground openings

    International Nuclear Information System (INIS)

    Marine, I.W.; Pratt, H.R.; Wahi, K.K.; Science Applications, Inc., La Jolla, CA; Science Applications, Inc., Albuquerque, NM)

    1982-01-01

    Numerical modeling techniques were used to determine the conditions required for seismic waves generated by an earthquake to cause instability to an underground opening or create fracturing and joint movement that would lead to an increase in the permeability of the rock mass. Three different rock types (salt, granite, and shale) were considered as host media for the repository located at a depth of 600 m. Special material models were developed to account for the nonlinear material behavior of each rock type. The sensitivity analysis included variations in the in situ stress ratio, joint geometry, and pore pressures, and the presence or absence of large fractures. Three different sets of earthquake motions were used to excite the rock mass. The methodology applied was found to be suitable for studying the effects of earthquakes on underground openings. In general, the study showed that moderate earthquakes (up to 0.41 g) did not cause instability of the tunnel or major fracturing of the rock mass; however, a tremor with accelerations up to 0.95 g was amplified around the tunnel, and fracturing occurred as a result of the seismic loading in salt and granite. In situ stress is a critical parameter in determining the subsurface effects of earthquakes but is nonexistent in evaluating the cause for surface damage. In shale with the properties assumed, even the moderate seismic load resulted in tunnel instability. These studies are all generic in nature and do not abrogate the need for site and design studies for specific facilities. 30 references, 14 figures, 8 tables

  2. Effects of applying three-dimensional seismic isolation system on the seismic design of FBR

    International Nuclear Information System (INIS)

    Hirata, Kazuta; Yabana, Shuichi; Kanazawa, Kenji; Matsuda, Akihiro

    1997-01-01

    In this study conceptional three-dimensional seismic isolation system for fast breeder reactor (FBR) is proposed. Effects of applying three-dimensional seismic isolation system on the seismic design for the FBR equipment are evaluated quantitatively. From the evaluation, it is concluded following effects are expected by applying the three-dimensional seismic isolation system to the FBR and the effects are evaluated quantitatively. (1) Reduction of membrane thickness of the reactor vessel (2) Suppression of uplift of fuels by reducing vertical seismic response of the core (3) Reduction of the supports for the piping system (4) Three-dimensional base isolation system for the whole reactor building is advantageous to the combined isolation system of horizontal base isolation for the reactor building and vertical isolation for the equipment. (author)

  3. Device for absorbing seismic effects on buildings

    International Nuclear Information System (INIS)

    Xercavins, Pierre; Pompei, Michel.

    1979-01-01

    Device for absorbing seismic effects. The construction or structure to be protected rests on its foundations through at least one footing formed of a stack of metal plates interlinked by layers of adhesive material, over at least a part of their extent, this material being an elastomer that can distort, characterized in that at least part of the area of some metal plates works in association with components which are able to absorb at least some of the energy resulting from friction during the relative movements of the metal plates against the distortion of the elastomer [fr

  4. Effect of Phase Transformations on Seismic Velocities

    Science.gov (United States)

    Weidner, D. J.; Li, L.; Whitaker, M.; Triplett, R.

    2017-12-01

    The radial velocity structure of the Earth consists of smooth variations of velocities with depth punctuated by abrupt changes of velocity, which are typically due to multivariant phase transformations, where high - low pressure phases can coexist. In this mixed phase region, both the effective shear and bulk moduli will be significantly reduced by the dynamic interaction of the propagating wave and the phase transition if the period of the wave is long enough relative to the kinetic time so that some of the transition can take place. In this presentation, we will give examples from both laboratory studies of phases transitions of Earth minerals and the calculated velocity profile based on our models. We focus on understanding the time limiting factor of the phase transformation in order to extrapolate laboratory results to Earth observations. Both the olivine to ringwoodite transition and KLB-1 partial melting are explored. We find that when the transformation requires diffusion, the kinetics are often slowed down considerably and as a result the diffusivity of atoms become the limiting factor of characteristic time. Specifically Fe-Mg exchange rate in the olivine-ringwoodite phase transition becomes the limiting factor that seismic waves are likely to sample. On the other hand, partial melting is an extremely fast phase transformation at seismic wave periods. We present evidence that ultrasonic waves, with a period of a few tens of nanoseconds, are slowed by the reduction of the effective elastic moduli in this case.

  5. Seismic verification of the Italian PEC fast reactor and effects of seismic conditions on the design

    International Nuclear Information System (INIS)

    Martelli, A.; Cecchini, F.; Masoni, P.; Maresca, G.; Castoldi, A.

    1988-01-01

    This paper deals with the aseismic design features of the Italian PEC fast reactor and the effects of seismic conditions on the reactor design. More precisely, after some notes on the main plant features, the paper reports on the design earthquakes adopted, the seismic monitoring procedures and the related actions, the design requirements, criteria and methods, and also provides a brief summary of the main research and development studies performed in support of design analysis. For the above-mentioned items, comparisons with the other fast reactors of the European Community countries are presented. Furthermore, the paper stresses the design modifications adopted to guarantee PEC seismic safety

  6. Letter report seismic shutdown system failure mode and effect analysis

    International Nuclear Information System (INIS)

    KECK, R.D.

    1999-01-01

    The Supply Ventilation System Seismic Shutdown ensures that the 234-52 building supply fans, the dry air process fans and vertical development calciner are shutdown following a seismic event. This evaluates the failure modes and determines the effects of the failure modes

  7. Effects of fault heterogeneity on seismic energy and spectrum

    Science.gov (United States)

    Dragoni, Michele; Santini, Stefano

    2017-12-01

    We study the effects of friction heterogeneity on the dynamics of a seismogenic fault. To this aim, we consider a fault model containing two asperities with different static frictions and a rate-dependent dynamic friction. We consider the seismic events produced by the consecutive failure of the two asperities and study their properties as functions of the ratio between static frictions. In particular, we calculate the moment rate, the stress evolution during fault slip, the average stress drop, the partitioning of energy release, the seismic energy, the far-field waveforms and the spectrum of seismic waves. These quantities depend to various extent on the friction distribution on the fault. In particular, the stress distribution on the fault is always strongly heterogeneous at the beginning of the seismic event. Seismic energy and frictional heat decrease with increasing friction heterogeneity, while seismic efficiency is constant. We obtain an equation relating seismic efficiency to the parameters of the friction law, showing that the efficiency is maximum for smaller values of dynamic friction. The seismic spectrum depends on the friction distribution as to the positions and the values of the minima. However, under the model assumption that the slip durations are the same for both asperities, the corner frequency is independent of the friction distribution, but it depends on the friction law and on the coupling between asperities. The model provides a relation between the total radiated energy and the seismic moment that is consistent with the empirical relation between the two quantities. The fault model with one asperity is also considered as a particular case. The model is applied to the 1965 Rat Islands (Alaska) earthquake and shows the role of fault heterogeneity in controlling the spatial distribution of stress drop as well as the time dependence and the final amount of radiated energy.

  8. Effects of Regulation on Induced Seismicity in Southern Kansas

    Science.gov (United States)

    Rubinstein, J. L.; Ellsworth, W. L.; Dougherty, S. L.

    2016-12-01

    The appearance of seismicity concurrent with the expansion of oil and gas activities in southern Kansas since September 2012 suggests that industrial operations are inducing earthquakes there. Much of the seismicity can be related to high-rate injection wells within 5 km of the earthquakes. There is significant complexity to the situation, though. Some of the seismicity, including the 2014 M4.8 Milan earthquake, the largest earthquake to occur in the area, lies at least 10km from high-rate injection wells. Additionally, the presence of high-rate wells does not guarantee that there will be nearby seismicity. Many of the highest-rate injection wells are located to the southwest of our study area, where there is minimal seismicity. We have also seen changes in earthquake rates shortly following the March 2015 enactment of new limits on the rate of wastewater disposal in five areas in southern Kansas. Overall, the earthquake rate has decreased significantly since these rules went into place. In more detail, however, earthquake rates within the five areas decreased, but the rate outside the five zones increased. It is likely that fluid-pressure diffusion is responsible for the migration of seismicity outside the areas of reduced injection because there is little injection in the areas unaffected by the new injection rules. This increase is also a reminder that seismicity can persist long after the reduction or cessation of injection. In addition to the effect of the new injection rules, it is possible that the reduction in injection may be partially caused by economic factors that have resulted in a decrease in the production of oil and gas. We have yet to disentangle the effects of the new injection rules and the low prices of oil and gas on the induced seismicity in southern Kansas.

  9. Effects of Irregular Bridge Columns and Feasibility of Seismic Regularity

    Science.gov (United States)

    Thomas, Abey E.

    2018-05-01

    Bridges with unequal column height is one of the main irregularities in bridge design particularly while negotiating steep valleys, making the bridges vulnerable to seismic action. The desirable behaviour of bridge columns towards seismic loading is that, they should perform in a regular fashion, i.e. the capacity of each column should be utilized evenly. But, this type of behaviour is often missing when the column heights are unequal along the length of the bridge, allowing short columns to bear the maximum lateral load. In the present study, the effects of unequal column height on the global seismic performance of bridges are studied using pushover analysis. Codes such as CalTrans (Engineering service center, earthquake engineering branch, 2013) and EC-8 (EN 1998-2: design of structures for earthquake resistance. Part 2: bridges, European Committee for Standardization, Brussels, 2005) suggests seismic regularity criterion for achieving regular seismic performance level at all the bridge columns. The feasibility of adopting these seismic regularity criterions along with those mentioned in literatures will be assessed for bridges designed as per the Indian Standards in the present study.

  10. Effects of Seismic Exploration on Mangrove Habitat in Tanzania ...

    African Journals Online (AJOL)

    There were few signs of recovery in the immediate vicinity of seismic lines, which appeared to be related to trampling effects on soil stability and changes in hydrology attributable to the loss of trees. Future research should target seedling and sapling abundance and growth rates, and soil structure, composition and nutrient ...

  11. Field site investigation: Effect of mine seismicity on groundwater hydrology

    International Nuclear Information System (INIS)

    Ofoegbu, G.I.; Hsiung, S.; Chowdhury, A.H.

    1995-04-01

    The results of a field investigation on the groundwater-hydrologic effect of mining-induced earthquakes are presented in this report. The investigation was conducted at the Lucky Friday Mine, a silver-lead-zinc mine in the Coeur d'Alene Mining District of Idaho. The groundwater pressure in sections of three fracture zones beneath the water table was monitored over a 24-mo period. The fracture zones were accessed through a 360-m-long inclined borehole, drilled from the 5,700 level station of the mine. The magnitude, source location, and associated ground motions of mining-induced seismic events were also monitored during the same period, using an existing seismic instrumentation network for the mine, augmented with additional instruments installed specifically for the project by the center for Nuclear Waste Regulatory Analyses (CNWRA). More than 50 seismic events of Richter magnitude 1.0 or larger occurred during the monitoring period. Several of these events caused the groundwater pressure to increase, whereas a few caused it to decrease. Generally, the groundwater pressure increased as the magnitude of seismic event increased; for an event of a given magnitude, the groundwater pressure increased by a smaller amount as the distance of the observation point from the source of the event increased. The data was examined using regression analysis. Based on these results, it is suggested that the effect of earthquakes on groundwater flow may be better understood through mechanistic modeling. The mechanical processes and material behavior that would need to be incorporated in such a model are examined. They include a description of the effect of stress change on the permeability and water storage capacity of a fracture rock mass; transient fluid flow; and the generation and transmission of seismic waves through the rock mass

  12. Inertial Effects on Finite Length Pipe Seismic Response

    Directory of Open Access Journals (Sweden)

    Virginia Corrado

    2012-01-01

    Full Text Available A seismic analysis for soil-pipe interaction which accounts for length and constraining conditions at the ends of a continuous pipe is developed. The Winkler model is used to schematize the soil-structure interaction. The approach is focused on axial strains, since bending strains in a buried pipe due to the wave propagation are typically a second-order effect. Unlike many works, the inertial terms are considered in solving equations. Accurate numerical simulations are carried out to show the influence of pipe length and constraint conditions on the pipe seismic strain. The obtained results are compared with results inferred from other models present in the literature. For free-end pipelines, inertial effects have significant influence only for short length. On the contrary, their influence is always important for pinned pipes. Numerical simulations show that a simple rigid model can be used for free-end pipes, whereas pinned pipes need more accurate models.

  13. Determination of Destress Blasting Effectiveness Using Seismic Source Parameters

    Science.gov (United States)

    Wojtecki, Łukasz; Mendecki, Maciej J.; Zuberek, Wacaław M.

    2017-12-01

    Underground mining of coal seams in the Upper Silesian Coal Basin is currently performed under difficult geological and mining conditions. The mining depth, dislocations (faults and folds) and mining remnants are responsible for rockburst hazard in the highest degree. This hazard can be minimized by using active rockburst prevention, where destress blastings play an important role. Destress blastings in coal seams aim to destress the local stress concentrations. These blastings are usually performed from the longwall face to decrease the stress level ahead of the longwall. An accurate estimation of active rockburst prevention effectiveness is important during mining under disadvantageous geological and mining conditions, which affect the risk of rockburst. Seismic source parameters characterize the focus of tremor, which may be useful in estimating the destress blasting effects. Investigated destress blastings were performed in coal seam no. 507 during its longwall mining in one of the coal mines in the Upper Silesian Coal Basin under difficult geological and mining conditions. The seismic source parameters of the provoked tremors were calculated. The presented preliminary investigations enable a rapid estimation of the destress blasting effectiveness using seismic source parameters, but further analysis in other geological and mining conditions with other blasting parameters is required.

  14. Response Analysis of an RC Cooling Tower Under Seismic and Windstorm Effects

    Directory of Open Access Journals (Sweden)

    D. Makovička

    2006-01-01

    Full Text Available The paper compares the RC structure of a cooling tower unit under seismic loads and under strong wind loads. The calculated values of the envelopes of the displacements and the internal forces due to seismic loading states are compared with the envelopes of the loading states due to the dead, operational and live loads, wind and temperature actions. The seismic effect takes into account the seismic area of ground motion 0.3 g and the ductility properties of a relatively rigid structure. The ductility is assessed as the reduction in seismic load. In this case the actions of wind pressure are higher than the seismicity effect under ductility correction. The seismic effects, taking into account the ductility properties of the structure, are lower than the actions of the wind pressure. The other static loads, especially temperature action due to the environment and surface insulation are very important for the design of the structure. 

  15. Global seismic effects of basin-forming impacts

    International Nuclear Information System (INIS)

    Hughes, H.G.; App, F.N.; McGetchin, T.R.

    1977-01-01

    Models of the thermal evolution of the moon and the terrestrial planets suggest that basin-forming impacts occurred when the planets had partially molten interiors overlain by thickening lithospheres, comparable in thickness to the basin radii. The effects of large impacts on planetary surfaces were investigated using a Lagrangian computer program which treats shock wave propagation and includes the effects of material strength, elastic-plastic behavior and material failure. The computer code and some physical details of the numerical techniques are described, and the results of several initial calculations are reported. The global seismic effects for cratering energies (10 24 and 10 25 J) intermediate between the Copernicus and Imbrium events on the moon, are studied and the phenomenologies for assumed solid and molten planetary interiors are compared. The principal results are as follows: (1) Far-field effects are largely independent of cratering mechanisms (e.g., simulated impact vs buried explosion). (2) Antipodal seismic effects are significantly enhanced by focusing and are of substantial magnitude. Vertical ground motion may be on the order of kilometers, and accelerations approach one lunar-g. (3) The most violent activity occurs at significant depth beneath the antipode, considerably after the passage of the initial compressive/rarefactive shock wave, and results from complex interactions with the free surface. (4) Seismic effects are decidedly more pronounced for a molten planet than for a solid one. (5) Tensile failure may occur at depths of tens of kilometers beneath the antipode, and may also occur over the entire surface, although at shallower depths

  16. Seismic effects on technological equipment and systems of nuclear power plants

    International Nuclear Information System (INIS)

    Masopust, R.; Pecinka, L.; Podrouzek, J.

    1983-01-01

    A survey is given of problems related to the construction of nuclear power plants with regard to seismic resistance. Sei--smic resistance of technological equipment is evaluated by experimental trials, calculation or the combination of both. Existing and future standards are given for the given field. The Czechoslovak situation is discussed as related to the construction of the Mochovce nuclear power plant. Procedures for testing seismic resistance, types of tests and methods of simulating seismic excitation are described. Antiseismic measures together with structural elements for limiting the seismic effects on technological equipment and nuclear power plant systems are summed up on the basis of foreign experience. (E.F.)

  17. Effects of seismic survey sound on cetaceans in the Northwest Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Moulton, Valerie D.; Holst, Meike [LGL Limited, Environmental Research Associates (Canada)

    2010-06-15

    Hydrocarbon exploration with marine seismic programs in the Canadian Beaufort Sea is expected to continue in the future. However the effect of those seismic surveys on cetaceans is a controversial subject, the sound emitted by airguns might result in hearing impairment or injury to marine mammals if they are at close range. The aim of this paper is to determine the behavior of cetaceans during seismic surveys. From 2003 to 2008, studies were conducted for 9180 hours over 8 seismic programs to observe the difference in number, sighting distance and behavior of marine mammals between seismic and non-seismic periods. Results showed that mysticetes and baleen whales tend to avoid the active airgun array while large toothed whales showed no difference in sighting rate and distances whether the airgun was active or not. This study showed that the effectiveness of ramping up the airgun to alert cetaceans of seismic operations depends on the species.

  18. Study on the application of ambient vibration tests to evaluate the effectiveness of seismic retrofitting

    Science.gov (United States)

    Liang, Li; Takaaki, Ohkubo; Guang-hui, Li

    2018-03-01

    In recent years, earthquakes have occurred frequently, and the seismic performance of existing school buildings has become particularly important. The main method for improving the seismic resistance of existing buildings is reinforcement. However, there are few effective methods to evaluate the effect of reinforcement. Ambient vibration measurement experiments were conducted before and after seismic retrofitting using wireless measurement system and the changes of vibration characteristics were compared. The changes of acceleration response spectrum, natural periods and vibration modes indicate that the wireless vibration measurement system can be effectively applied to evaluate the effect of seismic retrofitting. The method can evaluate the effect of seismic retrofitting qualitatively, it is difficult to evaluate the effect of seismic retrofitting quantitatively at this stage.

  19. The Lusi seismic experiment: An initial study to understand the effect of seismic activity to Lusi

    Energy Technology Data Exchange (ETDEWEB)

    Karyono, E-mail: karyonosu@gmail.com [Agency for Meteorology, Climatology and Geophysics (BMKG), Jakarta (Indonesia); OSLO University (Norway); Padjadjaran University (UNPAD), Bandung (Indonesia); Mazzini, Adriano; Sugiharto, Anton [OSLO University (Norway); Lupi, Matteo [ETH Zurich (Switzerland); Syafri, Ildrem [Padjadjaran University (UNPAD), Bandung (Indonesia); Masturyono,; Rudiyanto, Ariska; Pranata, Bayu; Muzli,; Widodo, Handi Sulistyo; Sudrajat, Ajat [Agency for Meteorology, Climatology and Geophysics (BMKG), Jakarta (Indonesia)

    2015-04-24

    The spectacular Lumpur Sidoarjo (Lusi) eruption started in northeast Java on the 29 of May 2006 following a M6.3 earthquake striking the island [1,2]. Initially, several gas and mud eruption sites appeared along the reactivated strike-slip Watukosek fault system [3] and within weeks several villages were submerged by boiling mud. The most prominent eruption site was named Lusi. The Lusi seismic experiment is a project aims to begin a detailed study of seismicity around the Lusi area. In this initial phase we deploy 30 seismometers strategically distributed in the area around Lusi and along the Watukosek fault zone that stretches between Lusi and the Arjuno Welirang (AW) complex. The purpose of the initial monitoring is to conduct a preliminary seismic campaign aiming to identify the occurrence and the location of local seismic events in east Java particularly beneath Lusi.This network will locate small event that may not be captured by the existing BMKG network. It will be crucial to design the second phase of the seismic experiment that will consist of a local earthquake tomography of the Lusi-AW region and spatial and temporal variations of vp/vs ratios. The goal of this study is to understand how the seismicity occurring along the Sunda subduction zone affects to the behavior of the Lusi eruption. Our study will also provide a large dataset for a qualitative analysis of earthquake triggering studies, earthquake-volcano and earthquake-earthquake interactions. In this study, we will extract Green’s functions from ambient seismic noise data in order to image the shallow subsurface structure beneath LUSI area. The waveform cross-correlation technique will be apply to all of recordings of ambient seismic noise at 30 seismographic stations around the LUSI area. We use the dispersive behaviour of the retrieved Rayleigh waves to infer velocity structures in the shallow subsurface.

  20. Effect of interconnectivity of structures against seismic load

    International Nuclear Information System (INIS)

    Bhuvaneshwari, P.; Elangovan, S.

    2003-01-01

    Since years world had experienced number of earthquakes and in India, zones have been modified according to the severity of earthquake and all this have made designers and engineers to concentrate rigorously to bring down the effect of damage to structures. Since the response of the structures to seismic force mainly depends on the distribution of mass, stiffness and damping characteristics an attempt is being made to compare and study the response by improving these characteristics in a simple building frame with and without infill. This in turn gives an idea of interconnecting the adjacent buildings of nuclear island to reduce the hazard to a minimum. (author)

  1. Influence of various parameters on effectiveness of seismic base isolation of nuclear equipment

    International Nuclear Information System (INIS)

    Ebisawa, K.; Kameoka, H.; Takenouchi, I.; Kajiki, S.

    1995-01-01

    Authors developed a methodology and EBISA code for evaluating the applicability and the effectiveness of seismic base isolation of nuclear equipment. In order to investigate the influence of various parameters on the effectiveness of seismic base isolation, a sensitivity analysis was carried out for an emergency transformer with the base isolation devices. It was proved that seismic base isolation of equipment is very effective. This effectiveness can be influenced by the differences of the base isolation devices and the direction of the input seismic wave. (author). 7 refs., 3 figs., 3 tabs

  2. 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

  3. Seismicity, seismic input and site effects in the Sahel-Algiers region (north Algeria)

    International Nuclear Information System (INIS)

    Harbi, A.; Maouche, S.; Oussadou, F.; Vaccari, F.; Aoudia, A.; Panza, G.F.; Benouar, D.

    2005-07-01

    Algiers city is located in a seismogenic zone. To reduce the impact of seismic risk in this capital city, a realistic modelling of the seismic ground motion using the hybrid method that combines the finite-differences method and the modal summation, is conducted. For this purpose, a complete database in terms of geological, geophysical and earthquake data is constructed. A critical re-appraisal of the seismicity of the zone (2.25 deg. E-3.50 deg. E, 36.50 deg. N-37.00 deg. N) is performed and an earthquake list, for the period 1359-2002, is compiled. The analysis of existing and newly retrieved macroseismic information allowed the definition of earthquake parameters of macroseismic events for which a degree of reliability is assigned. Geological cross-sections have been built up to model the seismic ground motion in the city, caused by the 1989 Mont-Chenoua and the 1924 Douera earthquakes; a set of synthetic seismograms and response spectral ratio is produced for Algiers. The numerical results show that the soft sediments in Algiers centre are responsible of the noticed amplification of the seismic ground motion. (author)

  4. Scenarios for local seismic effects of Tulcea (Romania) crustal earthquakes, preliminary approach for the seismic microzoning of Tulcea city

    Science.gov (United States)

    Florin Bǎlan, Å.žTefan; Apostol, Bogdan; Chitea, F.; Anghelache, Mirela Adriana; Cioflan, Carmen O.; Serban, A.

    2010-05-01

    The discussed area, Tulcea, is delimitated by the Scythian Platform in the North and Moessian Platform in the South, not far from the Black Sea coast. Natural disasters in the city could occur due to Vrancea intermediate-depth (subcrustal) earthquakes and crustal earthquakes caused by active faults. In the last 30 years three important seismic events affected the region of interest with the following recorded magnitudes: MW = 5.1 (13.11.1981) followed in the same day by 6 aftershocks (at depth 0-9 km) with MW = 2.9-3.3; MW = 5 (27.04.1986) and MW = 4.9 (3.10.2004) followed by two aftershocks. Information about the seismic zone of Tulcea is from three seismic catalogues made by Florinescu (1958), Constantinescu and Mârza (1980) and ROMPLUS (2008), but for urban planning of Tulcea city is very important to be better understood the effect of active faults (Măcin-Cerna, Tulcea-Isaccea, Peceneaga-Camena etc) located in the Pre-Dobrogean Depression (our interest area) in the two parts of the city. Regarding the effects of Vrancea subcrustal earthquakes, as the Tulcea city is situated relatively at a large distance from the epicenters, there is necessary to improve the actual method of microzonation based on Medvedev's method. In order to discuss the local seismic site effects we have considered two scenarios, which take into account the characteristics of the seismogenic area. The first one considers the city exposed to a seismic event with magnitude Mw = 5.1 from Sf. Gheorghe fault and the second one considers the city exposed to an earthquake from the EV zone (superficial). The earthquake epicentres are located in very active seismic areas. The absolute response spectra at the bedrock and at surface will be calculated and the characteristic transfer functions, as well. Nonlinear effects induced by significant deformations need a certain method - linear equivalent - for a multistratified zone, as we considered for the Tulcea superficial area. Therefore, important

  5. 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.)

  6. Effect of β on Seismic Vulnerability Curve for RC Bridge Based on Double Damage Criterion

    International Nuclear Information System (INIS)

    Feng Qinghai; Yuan Wancheng

    2010-01-01

    In the analysis of seismic vulnerability curve based on double damage criterion, the randomness of structural parameter and randomness of seismic should be considered. Firstly, the distribution characteristics of structure capability and seismic demand are obtained based on IDA and PUSHOVER, secondly, the vulnerability of the bridge is gained based on ANN and MC and a vulnerability curve according to this bridge and seismic is drawn. Finally, the analysis for a continuous bridge is displayed as an example, and parametric analysis for the effect of β is done, which reflects the bridge vulnerability overall from the point of total probability, and in order to reduce the discreteness, large value of β are suggested.

  7. Effects of induced stress on seismic forward modelling and inversion

    Science.gov (United States)

    Tromp, Jeroen; Trampert, Jeannot

    2018-05-01

    We demonstrate how effects of induced stress may be incorporated in seismic modelling and inversion. Our approach is motivated by the accommodation of pre-stress in global seismology. Induced stress modifies both the equation of motion and the constitutive relationship. The theory predicts that induced pressure linearly affects the unstressed isotropic moduli with a slope determined by their adiabatic pressure derivatives. The induced deviatoric stress produces anisotropic compressional and shear wave speeds; the latter result in shear wave splitting. For forward modelling purposes, we determine the weak form of the equation of motion under induced stress. In the context of the inverse problem, we determine induced stress sensitivity kernels, which may be used for adjoint tomography. The theory is illustrated by considering 2-D propagation of SH waves and related Fréchet derivatives based on a spectral-element method.

  8. International activities concerning seismic effects on underground structures

    International Nuclear Information System (INIS)

    Hakala, W.W.

    1982-01-01

    At the 5th Annual Meeting of the ITA in Atlanta, Georgia, on June 15-17, 1979, the General Assembly approved the formation of the Working Group Seismic Effects on Underground Structures. The objectives of this Working Group are to: (1) collect data on earthquake damage to underground facilities throughout the world; (2) collect information on aseismic design procedures used within the various countries; and (3) synthesize the information and disseminate the results to the member nations of ITA. William W. Hakala of the US was designated the Animateur of the Working Group. The Working Group decided on the following sequential course of action to achieve the stated objectives: (1) continue to develop a bibliograhy on damages to underground structures by dynamic forces. This will be an ongoing activity of the Working Group; (2) each country is to develop a summary of case histories of earthquake damage to underground structures. These case histories will be discussed at the next meeting of the Working Group in order to identify those parameters that permit or prevent such damage; (3) the state-of-the-art paper on earthquake damage to underground opening being prepared in the US (John A. Blume and Associates, Engineers) is presently being printed and will then be distributed to the membership for comment. This report will form the basis for the activities described below; (4) the above activities should lead to a textbook - like document that provides a design philosophy for underground structures subjected to seismic forces; (5) the work tasks will suggest needed research to solve the identified problems. At each Working Group meeting the member nation delegates will provide a summary of research progress in their countries. These research needs will be documented, reviewed, revised, and disseminated on an annual basis

  9. Effective updating process of seismic fragilities using Bayesian method and information entropy

    International Nuclear Information System (INIS)

    Kato, Masaaki; Takata, Takashi; Yamaguchi, Akira

    2008-01-01

    Seismic probabilistic safety assessment (SPSA) is an effective method for evaluating overall performance of seismic safety of a plant. Seismic fragilities are estimated to quantify the seismically induced accident sequences. It is a great concern that the SPSA results involve uncertainties, a part of which comes from the uncertainty in the seismic fragility of equipment and systems. A straightforward approach to reduce the uncertainty is to perform a seismic qualification test and to reflect the results on the seismic fragility estimate. In this paper, we propose a figure-of-merit to find the most cost-effective condition of the seismic qualification tests about the acceleration level and number of components tested. Then a mathematical method to reflect the test results on the fragility update is developed. A Bayesian method is used for the fragility update procedure. Since a lognormal distribution that is used for the fragility model does not have a Bayes conjugate function, a parameterization method is proposed so that the posterior distribution expresses the characteristics of the fragility. The information entropy is used as the figure-of-merit to express importance of obtained evidence. It is found that the information entropy is strongly associated with the uncertainty of the fragility. (author)

  10. 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

  11. Effect of the selected seismic energy dissipation capacity on the materials quantity for reinforced concrete walls

    Directory of Open Access Journals (Sweden)

    José Miguel Benjumea Royero

    2017-02-01

    Full Text Available Context: Regarding their design of reinforced concrete structural walls, the Colombian seismic design building code allows the engineer to select one of the three seismic energy dissipation capacity (ordinary, moderate, and special depending on the seismic hazard of the site. Despite this, it is a common practice to choose the minor requirement for the site because it is thought that selecting a higher requirement will lead to larger structural materials amounts and, therefore, cost increments.  Method: In this work, an analytical study was performed in order to determine the effect of the selected energy dissipation capacity on the quantity of materials and ductility displacement capacity of R/C walls. The study was done for a region with low seismic hazard, mainly because this permitted to explore and compare the use of the three seismic energy dissipations capacities. The effect of different parameters such as the wall total height and thickness, the tributary loaded area, and the minimum volumetric steel ratio were studied. Results: The total amount of steel required for the walls with moderate and special energy dissipation capacity corresponds, on average, to 77% and 89%, respectively, of the quantity required for walls with minimum capacity. Conclusions: it is possible to achieve reductions in the total steel required weight when adopting either moderated or special seismic energy dissipation instead of the minimum capacity.  Additionally, a significant increment in the seismic ductility displacements capacity of the wall was obtained.

  12. Applicability of deterministic methods in seismic site effects modeling

    International Nuclear Information System (INIS)

    Cioflan, C.O.; Radulian, M.; Apostol, B.F.; Ciucu, C.

    2005-01-01

    The up-to-date information related to local geological structure in the Bucharest urban area has been integrated in complex analyses of the seismic ground motion simulation using deterministic procedures. The data recorded for the Vrancea intermediate-depth large earthquakes are supplemented with synthetic computations all over the city area. The hybrid method with a double-couple seismic source approximation and a relatively simple regional and local structure models allows a satisfactory reproduction of the strong motion records in the frequency domain (0.05-1)Hz. The new geological information and a deterministic analytical method which combine the modal summation technique, applied to model the seismic wave propagation between the seismic source and the studied sites, with the mode coupling approach used to model the seismic wave propagation through the local sedimentary structure of the target site, allows to extend the modelling to higher frequencies of earthquake engineering interest. The results of these studies (synthetic time histories of the ground motion parameters, absolute and relative response spectra etc) for the last 3 Vrancea strong events (August 31,1986 M w =7.1; May 30,1990 M w = 6.9 and October 27, 2004 M w = 6.0) can complete the strong motion database used for the microzonation purposes. Implications and integration of the deterministic results into the urban planning and disaster management strategies are also discussed. (authors)

  13. Full wavefield migration: Seismic imaging using multiple scattering effects

    NARCIS (Netherlands)

    Davydenko, M.

    2016-01-01

    Seismic imaging aims at revealing the structural information of the subsurface using the reflected wavefields captured by sensors usually located at the surface. Wave propagation is a complex phenomenon and the measured data contain a set of backscattered events including not only primary

  14. Effect of Kepler calibration on global seismic and background parameters

    Directory of Open Access Journals (Sweden)

    Salabert David

    2017-01-01

    Full Text Available Calibration issues associated to scrambled collateral smear affecting the Kepler short-cadence data were discovered in the Data Release 24 and were found to be present in all the previous data releases since launch. In consequence, a new Data Release 25 was reprocessed to correct for these problems. We perform here a preliminary study to evaluate the impact on the extracted global seismic and background parameters between data releases. We analyze the sample of seismic solar analogs observed by Kepler in short cadence between Q5 and Q17. We start with this set of stars as it constitutes the best sample to put the Sun into context along its evolution, and any significant differences on the seismic and background parameters need to be investigated before any further studies of this sample can take place. We use the A2Z pipeline to derive both global seismic parameters and background parameters from the Data Release 25 and previous data releases and report on the measured differences.

  15. SHAKING TABLE TEST AND EFFECTIVE STRESS ANALYSIS ON SEISMIC PERFORMANCE WITH SEISMIC ISOLATION RUBBER TO THE INTERMEDIATE PART OF PILE FOUNDATION IN LIQUEFACTION

    Science.gov (United States)

    Uno, Kunihiko; Otsuka, Hisanori; Mitou, Masaaki

    The pile foundation is heavily damaged at the boundary division of the ground types, liquefied ground and non-liquefied ground, during an earthquake and there is a possibility of the collapse of the piles. In this study, we conduct a shaking table test and effective stress analysis of the influence of soil liquefaction and the seismic inertial force exerted on the pile foundation. When the intermediate part of the pile, there is at the boundary division, is subjected to section force, this part increases in size as compared to the pile head in certain instances. Further, we develop a seismic resistance method for a pile foundation in liquefaction using seismic isolation rubber and it is shown the middle part seismic isolation system is very effective.

  16. Fluid effects on the core seismic behavior of a liquid metal reactor

    International Nuclear Information System (INIS)

    Koo, Gyeong Hoi; Lee, Jae Han

    2004-01-01

    In this paper, a numerical application algorithm for applying the CFAM (Consistent Fluid Added Mass) matrix for a core seismic analysis is developed and applied to the 7-ducts core system to investigate the fluid effects on the dynamic characteristics and the seismic time history responses. To this end, three cases such as the in-air condition, the in-water condition without the fluid coupling terms, and the in-water condition with the fluid coupling terms are considered in this paper. From modal analysis, the core duct assemblies revealed strongly coupled out-of-phase vibration modes unlike the other cases with the fluid coupling terms considered. From the results of the seismic time history analysis, it was also verified that the fluid coupling terms in the CFAM matrix can significantly affect the impact responses and the seismic displacement responses of the ducts

  17. Seismic velocity uncertainties and their effect on geothermal predictions: A case study

    Science.gov (United States)

    Rabbel, Wolfgang; Köhn, Daniel; Bahadur Motra, Hem; Niederau, Jan; Thorwart, Martin; Wuttke, Frank; Descramble Working Group

    2017-04-01

    Geothermal exploration relies in large parts on geophysical subsurface models derived from seismic reflection profiling. These models are the framework of hydro-geothermal modeling, which further requires estimating thermal and hydraulic parameters to be attributed to the seismic strata. All petrophysical and structural properties involved in this process can be determined only with limited accuracy and thus impose uncertainties onto the resulting model predictions of temperature-depth profiles and hydraulic flow, too. In the present study we analyze sources and effects of uncertainties of the seismic velocity field, which translate directly into depth uncertainties of the hydraulically and thermally relevant horizons. Geological sources of these uncertainties are subsurface heterogeneity and seismic anisotropy, methodical sources are limitations in spread length and physical resolution. We demonstrate these effects using data of the EU-Horizon 2020 project DESCRAMBLE investigating a shallow super-critical geothermal reservoir in the Larderello area. The study is based on 2D- and 3D seismic reflection data and laboratory measurements on representative rock samples under simulated in-situ conditions. The rock samples consistently show P-wave anisotropy values of 10-20% order of magnitude. However, the uncertainty of layer depths induced by anisotropy is likely to be lower depending on the accuracy, with which the spatial orientation of bedding planes can be determined from the seismic reflection images.

  18. Analysis of seismic effects on reinforced concrete structures

    International Nuclear Information System (INIS)

    Tai, A.A.

    1981-12-01

    An important bibliographical research was undertaken in order to make the best possible analysis of the dynamic behaviour of materials and of structural components. This research work was completed by the study of the structures tested on a seismic table. The results obtained from this preliminary study, particularly those concerning the modification in the rigidity of reinforced concrete structures under alternate and seismic loading, enabled a calculation method (called ''equivalent static'') to be drawn up for analyzing the behaviour of reinforced concrete structures in earthquakes. This method takes into account the non-linearity of the behaviour of materials, in particular. The earthquake responses that were obtained by this method on gantries tested on a vibrating table, tally very satisfactorily with the test figures [fr

  19. Requirements on PWR reactor design with respect to seismic effects

    International Nuclear Information System (INIS)

    Novak, J.; Pecinka, L.

    1981-01-01

    From the seismic point of view the individual parts of a nuclear power plant must be built such as to allow the shutdown of the reactor up to the safe shutdown earthquake level, the removal of after-heat and the prevention of uncontrolled release of radioactivity into the environment. To the level of operating basic earthquake the plant must be designed such as to allow the operation of the reactor for a period of 100 hours from the seismic event without exceeding the permissible annual dose to personnel and population. The possibility of a loss-of-coolant accident owing to a seismic event is reduced mainly by the integrated performance of the primary circuit, the high-strength structure, the insulation of the main components from the shift of the foundations and the use of floating structures. The pressure vessel of the WWER-1000 reactor is therefore pAaced in a shaft on a support ring and is locked by another support ring. (Z.M.)

  20. Effect of gravity loading on inelastic seismic response of reinforced concrete structures

    International Nuclear Information System (INIS)

    Chowdhury, Rajib; Reddy, G. Rami; Roy, Raghupati; Dutta, Sekhar Chandra

    2003-01-01

    The effect of gravity loading is not considered in inelastic seismic response to avoid complexity and to reduce the number of influencing parameters. However, the possibility of considerable effect of this factor is indicated in many studies on inelastic seismic behaviour of structures. Hence, it is necessary to study the nature and extent of this effect on inelastic seismic behaviour of structures. The present paper attempts to fulfill this objective by studying the variation of energy dissipation due to presence of various level of axial load. The study is further extended to see the effect of axial force due to gravity loading on the ductility demand of hysteretic energy demand arising in structural elements of a simple one storey structures. The study shows that the presence of axial force may increase the energy dissipation capacity of structure leading to a reduction in ductility demand. (author)

  1. Analysis of Bi-directional Effects on the Response of a Seismic Base Isolation System

    International Nuclear Information System (INIS)

    Park, Hyung-Kui; Kim, Jung-Han; Kim, Min Kyu; Choi, In-Kil

    2014-01-01

    The floor response spectrum depends on the height of the floor of the structure. Also FRS depends on the characteristics of the seismic base isolation system such as the natural frequency, damping ratio. In the previous study, the floor response spectrum of the base isolated structure was calculated for each axis without considering bi-directional effect. However, the shear behavior of the seismic base isolation system of two horizontal directions are correlated each other by the bi-directional effects. If the shear behavior of the seismic isolation system changes, it can influence the floor response spectrum and displacement response of isolators. In this study, the analysis of a bi-directional effect on the floor response spectrum was performed. In this study, the response of the seismic base isolation system based on the bi-directional effects was analyzed. By analyzing the time history result, while there is no alteration in the maximum shear force of seismic base isolation system, it is confirmed that the shear force is generally more decreased in a one-directional that in a two-directional in most parts. Due to the overall decreased shear force, the floor response spectrum is more reduced in a two-directional than in a one-directional

  2. Combined effects of traveling seismic waves and soil nonlinearity on nuclear power plant response

    International Nuclear Information System (INIS)

    Lee, T.H.; Charman, C.M.

    1981-01-01

    The effects of ground motion nonuniformity on the seismic input have been actively studied in recent years by considering the passage of traveling seismic waves. These studies gave rise to a new class of soil-structure interaction problems in which the seismic input is modified as a result of the spatial variations of ground motion. The phenomena were usually studied by using the elastic half-space simulation or discrete spring-models for modeling the soil medium. Finite element methods were also used recently on a limited scope. Results obtained from these investigations are often manifested by an attenuation of translational excitation along with an addition of rotational ground motion input. The decrease in structural response resulting from the input loss in the translational component was often insignificant since the response reduction tends to be offset by the effects from rotational input. The traveling wave effects have, so far, been investigated within the framework of linear theory with soil nonlinearity ignored. Conversely, the incorporation of soil nonlinearity in soil-structure interaction analyses has been done without including wave effect. Seismic analyses considering the hysteretic behavior of soil have been performed using highly idealized models for steady-state solution. More elaborate nonlinear seismic models deal with only the strain-dependent soil modulus rather than the transient unloading-reloading type of hysteretic characteristics of soil under a time-function input of earthquake trace. Apparently, the traveling wave effect and soil nonlinearity have been separately treated in the past. The purpose of this paper is to demonstrate that these two major effects can be combined in one model such that the influence of wave passage is reflected through the hysteretic behavior of soil particles, and thereby achieving significant reduction in seismic loads. (orig./RW)

  3. Effect of fuel assembly when changing from AFA 2G to AFA 3G on seismic loads of reactor internal

    International Nuclear Information System (INIS)

    Liu Wenjin; Zeng Zhongxiu; Ye Xianhui; Wu Wanjun

    2013-01-01

    Nonlinear seismic model for reactor with fuel assemblies of AFA 2G and AFA 3G is established. Using ANSYS software, seismic nonlinear time -history analysis is completed and the effects on seismic loads of reactor system are obtained. The result shows that when the fuel assembly changing from AFA 2G to AFA 3G, it is necessary to reevaluate the fuel assembly itself, but not the reactor internal. (authors)

  4. Geo-Proxy-Based Site Classification for Regional Zonation of Seismic Site Effects in South Korea

    Directory of Open Access Journals (Sweden)

    Chang-Guk Sun

    2018-02-01

    Full Text Available Seismic site effects and topographic effects related to ground motion occur during an earthquake due to site-specific geotechnical or geological characteristics, including the geological or geographical structure and the characteristics of near-surface sub-soil layers. Site-specific site effects due to geological conditions have been confirmed in recent earthquake events. Earthquake-induced damage has mainly occurred at accumulated soft soil layers under basins or along coasts and rivers. An alternative method has recently been proposed for evaluating regional seismic site effects and amplification factors using digital elevation models (DEM. High-quality DEMs at high resolutions may be employed to resolve finer-scale variations in topographic gradients and consequently, correlated site response parameters. Because there are many regions in South Korea lacking borehole datasets, which are insufficient for site classification only using borehole datasets, a DEM-based proxy for seismic zonation can be effective. Thus, in this study, geo-proxy-based site classification was proposed based on empirical correlations with site response parameters and conducted for regional zonation of seismic site effects to identify the amplification of characteristics in the western metropolitan areas of South Korea, depending on the site-specific geo-spatial conditions.

  5. Effects of relay chatter in seismic probabilistic safety analysis

    International Nuclear Information System (INIS)

    Reed, J.W.; Shiu, K.K.

    1985-01-01

    In the Zion and Indian Point Probabilistic Safety Studies, relay chatter was dismissed as a credible event and hence was not formally included in the analyses. Although little discussion is given in the Zion and Indian Point PSA documentation concerning the basis for this decision, it has been expressed informally that it was assumed that the operators will be able to reset all relays in a timely manner. Currently, it is the opinion of many professionals that this may be an oversimplification. The three basic areas which must be considered in addressing relay chatter include the fragility of the relays per se, the reliability of the operators to reset the relays and finally the systems response aspects. Each of these areas is reviewed and the implications for seismic PSA are discussed. Finally, recommendations for future research are given

  6. Effect of soil-foundation-structure interaction on the seismic response of wind turbines

    Directory of Open Access Journals (Sweden)

    Sam Austin

    2017-09-01

    Full Text Available Soil-foundation-structure interaction can affect the seismic response of wind turbines. This paper studies the effects of soil-foundation-structure interaction on the seismic response of 65 kW, 1 MW, and 2 MW horizontal-axis wind turbines with truncated cone steel towers. Four types of foundations with frequency-based design were analyzed, including spread foundation, mono pile, pile group with cap, and anchored spread foundation. Soil is modeled both implicitly (subgrade reaction modulus and explicitly. The finite element model developed using the ANSYS program was first validated using experimental data. Numerical models are then analyzed in both frequency and time domains using the Block Lanczos and generalized HHT-α formulations. Recommendations were given to simplify the soil-foundation-structure interaction analysis of wind turbines subjected to seismic loading.

  7. Seismic effects on the reliability of polar cranes for nuclear power plants

    International Nuclear Information System (INIS)

    Kaiser, W.; Friedrich, H.; Knoefel, L.

    1985-01-01

    In order to meet the requirements of nuclear safety reactor components have to be designed aseismically. A model for studying simulated seismic effects on the reliability of containment equipment polar cranes is presented. Based on this model vertical and horizontal motions of the crane are investigated. Emphasis is laid on non-linearities caused by malfunctions such as lift of the crane from the runaway, lift of the trolley from the beams, slackening of the ropes as well as sliding of blocked track wheels. Seismic excitations are simulated by computer produced accelerograms

  8. Seismic testing

    International Nuclear Information System (INIS)

    Sollogoub, Pierre

    2001-01-01

    This lecture deals with: qualification methods for seismic testing; objectives of seismic testing; seismic testing standards including examples; main content of standard; testing means; and some important elements of seismic testing

  9. The Effect of Corrosion on the Seismic Behavior of Buried Pipelines and a Remedy for Their Seismic Retrofit

    International Nuclear Information System (INIS)

    Hosseini, Mahmood; Salek, Shamila; Moradi, Masoud

    2008-01-01

    The effect of corrosion phenomenon has been investigated by performing some sets of 3-Dimensional Nonlinear Time History Analysis (3-D NLTHA) in which soil structure interaction as well as wave propagation effects have been taken into consideration. The 3-D NLTHA has been performed by using a finite element computer program, and both states of overall and local corrosions have been considered for the study. The corrosion has been modeled in the computer program by introducing decreased values of either pipe wall thickness or modulus of elasticity and Poisson ratio. Three sets of 3-component accelerograms have been used in analyses, and some appropriate numbers of zeros have been added at the beginning of records to take into account the wave propagation in soil and its multi-support excitation effect. The soil has been modeled by nonlinear springs in longitudinal, lateral, and vertical directions. A relatively long segment of the pipeline has been considered for the study and the effect of end conditions has been investigated by assuming different kinds end supports for the segment. After studying the corroded pipeline, a remedy has been considered for the seismic retrofit of corroded pipe by using a kind of Fiber Reinforced Polymers (FRP) cover. The analyses have been repeated for the retrofitted pipeline to realize the adequacy of FRP cover. Numerical results show that if the length of the pipeline segment is large enough, comparing to the wave length of shear wave in the soil, the end conditions do not have any major effect on the maximum stress and strain values in the pipe. Results also show that corrosion can lead to the increase in plastic strain values in the pipe up to 4 times in the case of overall corrosion and up to 20 times in the case of local corrosion. The satisfactory effect of using FRP cover is also shown by the analyses results, which confirm the decrease of strain values to 1/3

  10. The Effect of Corrosion on the Seismic Behavior of Buried Pipelines and a Remedy for Their Seismic Retrofit

    Science.gov (United States)

    Hosseini, Mahmood; Salek, Shamila; Moradi, Masoud

    2008-07-01

    The effect of corrosion phenomenon has been investigated by performing some sets of 3-Dimensional Nonlinear Time History Analysis (3-D NLTHA) in which soil structure interaction as well as wave propagation effects have been taken into consideration. The 3-D NLTHA has been performed by using a finite element computer program, and both states of overall and local corrosions have been considered for the study. The corrosion has been modeled in the computer program by introducing decreased values of either pipe wall thickness or modulus of elasticity and Poisson ratio. Three sets of 3-component accelerograms have been used in analyses, and some appropriate numbers of zeros have been added at the beginning of records to take into account the wave propagation in soil and its multi-support excitation effect. The soil has been modeled by nonlinear springs in longitudinal, lateral, and vertical directions. A relatively long segment of the pipeline has been considered for the study and the effect of end conditions has been investigated by assuming different kinds end supports for the segment. After studying the corroded pipeline, a remedy has been considered for the seismic retrofit of corroded pipe by using a kind of Fiber Reinforced Polymers (FRP) cover. The analyses have been repeated for the retrofitted pipeline to realize the adequacy of FRP cover. Numerical results show that if the length of the pipeline segment is large enough, comparing to the wave length of shear wave in the soil, the end conditions do not have any major effect on the maximum stress and strain values in the pipe. Results also show that corrosion can lead to the increase in plastic strain values in the pipe up to 4 times in the case of overall corrosion and up to 20 times in the case of local corrosion. The satisfactory effect of using FRP cover is also shown by the analyses results, which confirm the decrease of strain values to 1/3.

  11. Viscoplastic discontinuum model of time-dependent fracture and seismicity effects in brittle rock

    CSIR Research Space (South Africa)

    Napier, JAL

    1997-10-01

    Full Text Available A model is proposed for the direct mechanistic simulation of seismic activity and stress transfer effects in deep level mines. The model uses a discontinuum viscoplastic formulation to relate the rate of slip on a crack to the shear stress acting...

  12. Intercomparison of liquid metal fast reactor seismic analysis codes. V. 3: Comparison of observed effects with computer simulated effects on reactor cores from seismic disturbances. Proceedings of a final research co-ordination meeting

    International Nuclear Information System (INIS)

    1996-05-01

    This publication contains the final papers summarizing the validation of the codes on the basis of comparison of observed effects with computer simulated effects on reactor cores from seismic disturbances. Refs, figs tabs

  13. Necessity of using heterogeneous ellipsoidal Earth model with terrain to calculate co-seismic effect

    Science.gov (United States)

    Cheng, Huihong; Zhang, Bei; Zhang, Huai; Huang, Luyuan; Qu, Wulin; Shi, Yaolin

    2016-04-01

    Co-seismic deformation and stress changes, which reflect the elasticity of the earth, are very important in the earthquake dynamics, and also to other issues, such as the evaluation of the seismic risk, fracture process and triggering of earthquake. Lots of scholars have researched the dislocation theory and co-seismic deformation and obtained the half-space homogeneous model, half-space stratified model, spherical stratified model, and so on. Especially, models of Okada (1992) and Wang (2003, 2006) are widely applied in the research of calculating co-seismic and post-seismic effects. However, since both semi-infinite space model and layered model do not take the role of the earth curvature or heterogeneity or topography into consideration, there are large errors in calculating the co-seismic displacement of a great earthquake in its impacted area. Meanwhile, the computational methods of calculating the co-seismic strain and stress are different between spherical model and plane model. Here, we adopted the finite element method which could well deal with the complex characteristics (such as anisotropy, discontinuities) of rock and different conditions. We use the mash adaptive technique to automatically encrypt the mesh at the fault and adopt the equivalent volume force replace the dislocation source, which can avoid the difficulty in handling discontinuity surface with conventional (Zhang et al., 2015). We constructed an earth model that included earth's layered structure and curvature, the upper boundary was set as a free surface and the core-mantle boundary was set under buoyancy forces. Firstly, based on the precision requirement, we take a testing model - - a strike-slip fault (the length of fault is 500km and the width is 50km, and the slippage is 10m) for example. Because of the curvature of the Earth, some errors certainly occur in plane coordinates just as previous studies (Dong et al., 2014; Sun et al., 2012). However, we also found that: 1) the co-seismic

  14. Seismic response and fragility evaluation for an Eastern US NPP including soil-structure interaction effects

    International Nuclear Information System (INIS)

    Ghiocel, Dan M.; Wilson, Paul R.; Thomas, Gary G.; Stevenson, John D.

    1998-01-01

    The paper discusses methodological aspects involved in a probabilistic seismic soil-structure interaction (SSI) analysis for a Seismic Probabilistic Risk Assessment (SPRA) review. An example of an Eastern US nuclear power plant (NPP) is presented. The approach presented herein follows the current practice of the Individual Plant Examination for External Events (IPEEE) program in the US. The NPP is founded on a relatively soft soil deposit, and thus the SSI effects on seismic responses are significant. Probabilistic models used for the idealization of the seismic excitation and the surrounding soil deposit are described. Using a lognormal format, computed random variability effects were combined with those proposed in the SPRA methodology guidelines. Probabilistic floor response spectra and structural fragilities for different NPP buildings were computed. Structural capacities were determined following the current practice which assumes independent median safety factors for strength and inelastic absorption. Limitations of the IPEEE practice for performing SPRA are discussed and alternate procedures, more rigorous and simple to implement, are suggested

  15. Seismic evaluation of a cooling water reservoir facility including fluid-structure and soil-structure interaction effects

    International Nuclear Information System (INIS)

    Kabir, A.F.; Maryak, M.E.

    1991-01-01

    Seismic analyses and structural evaluations were performed for a cooling water reservoir of a nuclear reactor facility. The horizontal input seismic motion was the NRC Reg. guide 1.60 spectrum shape anchored at 0.20g zero period acceleration. Vertical input was taken as two-thirds of the horizontal input. Soil structure interaction and hydrodynamic effects were addressed in the seismic analyses. Uncertainties in the soil properties were accounted for by considering three soil profiles. Two 2-dimensional SSI models and a 3-dimensional static model. Representing different areas of the reservoir structures were developed and analyzed to obtain seismic forces and moments, and accelerations at various locations. The results included in this paper indicated that both hydrodynamic and soil-structure interaction effects are significant contributors to the seismic responses of the water-retaining walls of the reservoir

  16. Seismic protection

    International Nuclear Information System (INIS)

    Herbert, R.

    1988-01-01

    To ensure that a nuclear reactor or other damage-susceptible installation is, so far as possible, tripped and already shut down before the arrival of an earthquake shock at its location, a ring of monitoring seismic sensors is provided around it, each sensor being spaced from it by a distance (possibly several kilometres) such that (taking into account the seismic-shock propagation velocity through the intervening ground) a shock monitored by the sensor and then advancing to the installation site will arrive there later than a warning signal emitted by the sensor and received at the installation, by an interval sufficient to allow the installation to trip and shut down, or otherwise assume an optimum anti-seismic mode, in response to the warning signal. Extra sensors located in boreholes may define effectively a three-dimensional (hemispherical) sensing boundary rather than a mere two-dimensional ring. (author)

  17. Induced Seismicity

    Science.gov (United States)

    Keranen, Katie M.; Weingarten, Matthew

    2018-05-01

    The ability of fluid-generated subsurface stress changes to trigger earthquakes has long been recognized. However, the dramatic rise in the rate of human-induced earthquakes in the past decade has created abundant opportunities to study induced earthquakes and triggering processes. This review briefly summarizes early studies but focuses on results from induced earthquakes during the past 10 years related to fluid injection in petroleum fields. Study of these earthquakes has resulted in insights into physical processes and has identified knowledge gaps and future research directions. Induced earthquakes are challenging to identify using seismological methods, and faults and reefs strongly modulate spatial and temporal patterns of induced seismicity. However, the similarity of induced and natural seismicity provides an effective tool for studying earthquake processes. With continuing development of energy resources, increased interest in carbon sequestration, and construction of large dams, induced seismicity will continue to pose a hazard in coming years.

  18. Realistic modelling of the seismic input: Site effects and parametric studies

    International Nuclear Information System (INIS)

    Romanelli, F.; Vaccari, F.; Panza, G.F.

    2002-11-01

    We illustrate the work done in the framework of a large international cooperation, showing the very recent numerical experiments carried out within the framework of the EC project 'Advanced methods for assessing the seismic vulnerability of existing motorway bridges' (VAB) to assess the importance of non-synchronous seismic excitation of long structures. The definition of the seismic input at the Warth bridge site, i.e. the determination of the seismic ground motion due to an earthquake with a given magnitude and epicentral distance from the site, has been done following a theoretical approach. In order to perform an accurate and realistic estimate of site effects and of differential motion it is necessary to make a parametric study that takes into account the complex combination of the source and propagation parameters, in realistic geological structures. The computation of a wide set of time histories and spectral information, corresponding to possible seismotectonic scenarios for different sources and structural models, allows us the construction of damage scenarios that are out of the reach of stochastic models, at a very low cost/benefit ratio. (author)

  19. Modeling the effects of structure on seismic anisotropy in the Chester gneiss dome, southeast Vermont

    Science.gov (United States)

    Saif, S.; Brownlee, S. J.

    2017-12-01

    Compositional and structural heterogeneity in the continental crust are factors that contribute to the complex expression of crustal seismic anisotropy. Understanding deformation and flow in the crust using seismic anisotropy has thus proven difficult. Seismic anisotropy is affected by rock microstructure and mineralogy, and a number of studies have begun to characterize the full elastic tensors of crustal rocks in an attempt to increase our understanding of these intrinsic factors. However, there is still a large gap in length-scale between laboratory characterization on the scale of centimeters and seismic wavelengths on the order of kilometers. To address this length-scale gap we are developing a 3D crustal model that will help us determine the effects of rotating laboratory-scale elastic tensors into field-scale structures. The Chester gneiss dome in southeast Vermont is our primary focus. The model combines over 2000 structural data points from field measurements and published USGS structural data with elastic tensors of Chester dome rocks derived from electron backscatter diffraction data. We created a uniformly spaced grid by averaging structural measurements together in equally spaced grid boxes. The surface measurements are then projected into the third dimension using existing subsurface interpretations. A measured elastic tensor for the specific rock type is rotated according to its unique structural input at each point in the model. The goal is to use this model to generate artificial seismograms using existing numerical wave propagation codes. Once completed, the model input can be varied to examine the effects of different subsurface structure interpretations, as well as heterogeneity in rock composition and elastic tensors. Our goal is to be able to make predictions for how specific structures will appear in seismic data, and how that appearance changes with variations in rock composition.

  20. Wave passage effects on the seismic response of a maglev vehicle moving on multi-span guideway

    Directory of Open Access Journals (Sweden)

    J. D. Yau

    Full Text Available As a seismic wave travels along the separate supports of an extended structure, the structure is subjected to multiple-support excitation due to seismic wave propagation. Considering the seismic wave passage effect, this paper describes seismic analysis of a maglev vehicle moving on a multiply supported gudieway. The guideway system is modeled as a series of simple beams and the vehicle as a four degrees-of-freedom (DOFs rigid bar equipped with multiple onboard PI+LQR hybrid controllers. The controller is used to regulate control voltage for tuning both magnetic forces of uplift levitation and lateral guidance in the maglev system. Numerical studies show that as a maglev vehicle is equipped with more supported magnets then they can provide more control gains for tuning the guidance forces of the moving vehicle, and mitigate seismic-induced lateral vibration of a maglev vehicle running a guideway.

  1. Evaluation of high frequency ground motion effects on the seismic capacity of NPP equipments

    International Nuclear Information System (INIS)

    Choi, In Kil; Seo, Jeong Moon; Choun, Young Sun

    2003-04-01

    In this study, the uniform hazard spectrum for the example Korean nuclear power plants sites were developed and compared with various response spectra used in past seismic PRA and SMA. It shows that the high frequency ground motion effects should be considered in seismic safety evaluations. The floor response spectra were developed using the direct generation method that can develop the floor response spectra from the input response spectrum directly with only the dynamic properties of structures obtained from the design calculation. Most attachment of the equipments to the structure has a minimum distortion capacity. This makes it possible to drop the effective frequency of equipment to low frequency before it is severely damaged. The results of this study show that the high frequency ground motion effects on the floor response spectra were significant, and the effects should be considered in the SPRA and SMA for the equipments installed in a building. The high frequency ground motion effects are more important for the seismic capacity evaluation of functional failure modes. The high frequency ground motion effects on the structural failure of equipments that attached to the floor by welding can be reduced by the distortion capacity of welded anchorage

  2. SUPPRESSING DIFFRACTION EFFECT USING KIRCHHOFF PRE-STACK TIME MIGRATION ON 2D SEISMIC MULTICHANNEL DATA AT FLORES SEA

    Directory of Open Access Journals (Sweden)

    Tumpal Benhard Nainggolan

    2017-07-01

    Full Text Available 2D seismic multichannel survey has been carried out by Marine Geological Institute of Indonesia to interpret imaging and sub-surface geological information in the Flores Sea. Seismic data processing starts from pre-processing until migration stage. Migration is an important stage in the seismic processing, because at this stage the effects of diffraction and oblique reflectors caused by fault, salt domes, wedging, etc. will be repositioned to the actual points. One example of diffraction effects can be seen on the seismic section of a conventional stacking that have not migrated, i.e. resulting in an apparent bowtie reflector. Geologists find difficulties in interpreting geological information from diffracted seismic section, so it needs further processing to overcome the effects. By using Kirchhoff method and carried out during the Pre-Stack Time Migration (PSTM, this method turns out to produce migrated seismic section which is much better than conventional stacked one. This is due to the Kirchhoff method suppressed the identified diffraction effects, so that the geologist can interpret geological structure of the resulting migrated seismic section of the Flores Sea.

  3. Effect of supporting structure stiffness on the drive train assembly of an induced draft cooling tower under seismic effects

    International Nuclear Information System (INIS)

    Raghavan, N.; Ramasubramanian, S.; Khan, K.

    2005-01-01

    In a nuclear power project an induced draft cooling tower, as a safety-related structure and part of the main cooling system, has to perform satisfactorily under designated seismic effects. While the structural elements can be designed by conventional methods to ensure adequate safety, the seismic qualification of the mechanical components poses a challenge. The paper describes a methodology adopted for the seismic qualification of a typical Drive Train Assembly for the axial flow fan of an induced draft cooling tower, to ensure the structural integrity and functional operability of the assembly during Operating Base Earthquake and Safe Shutdown Earthquake conditions. This is achieved by performing a detailed finite element analysis of the rotating equipment assembly consisting of the electric motor, gear box and fan along with the drive shaft between the motor and the gear box. The various components are modeled using beam elements, plate elements and spring elements to idealize the flexible connections and supports. The floor response spectra derived from a dynamic analysis of the overall structure under stipulated seismic acceleration spectra are the main excitation inputs into the system. The results validate the adequacy of gaps for movement and the strengths of the couplings and bolts to withstand the applied loads. The assumed modeling and analysis methodology are seen to be acceptable procedures for seismic qualification of important components of the cooling tower. (authors)

  4. Seismic changes industry

    International Nuclear Information System (INIS)

    Taylor, G.

    1992-01-01

    This paper discusses the growth in the seismic industry as a result of the recent increases in the foreign market. With the decline of communism and the opening of Latin America to exploration, seismic teams have moved out into these areas in support of the oil and gas industry. The paper goes on to discuss the improved technology available for seismic resolution and the subsequent use of computers to field-proof the data while the seismic team is still on-site. It also discusses the effects of new computer technology on reducing the amount of support staff that is required to both conduct and interpret seismic information

  5. Influence of crustal layering and thickness on co-seismic effects of Wenchuan earthquake

    Directory of Open Access Journals (Sweden)

    Tan Hongbo

    2011-02-01

    Full Text Available Using the PSGRN/PSCMP software and the fault model offered by USGS and on the basis of finite rectangular dislocation theory and the local layered wave velocity structures of the crust-upper-mantle, the influences of crustal layering and thickness on co-seismic gravity changes and deformation of Wenchuan earthquake have been simulated. The results indicate that; the influences have a relationship with the attitude of faults and the relative position between calculated points and fault. The difference distribution form of simulated results between the two models is similar to that of co-seismic effect. For the per centum distribution, it’s restricted by the zero line of the co-seismic effects obviously. Its positive is far away from the zero line. For the crustal thickness, the effect is about 10% – 20%. The negative and the effect over 30% focus around the zero line. The average influences of crustal layering and thickness for the E-W displacement, N-S displacement, vertical displacement and gravity changes are 18.4%,18.0%, 15.8% and 16.2% respectively, When the crustal thickness is 40 km, they are 4.6%, 5.3%, 3.8% and 3.8%. Then the crustal thickness is 70 km, the average influences are 3.5%, 4.6%, 3.0% and 2.5% respectively.

  6. Methods for the seismic effect analysis on the nuclear power station structures

    International Nuclear Information System (INIS)

    Jeanpierre, F.; Livolant, M.

    1980-01-01

    Seismic activity in France is far from being as great as in other parts of the globe, for instance Japan, California and Peru, in particular, and very few people are shocked at the idea of having to suffer from an earthquake, although periodically, such as at Arette, Oleron, etc., events do occur to remind one that seismic tremors of significant intensity can happen. In the case of nuclear reactors and given the serious secondary effects that uncontrolled destructions could involve, particularly the bursting of containment vessels or the non operation of safety systems such as the automatic drop of rods to halt the chain reaction, the earthquake hazard must be taken into account, in terms of the location of the power station, and the effects of the seism carefully estimated. The purpose of this report is briefly to describe the methods used to this end [fr

  7. Effects of Source RDP Models and Near-source Propagation: Implication for Seismic Yield Estimation

    Science.gov (United States)

    Saikia, C. K.; Helmberger, D. V.; Stead, R. J.; Woods, B. B.

    - It has proven difficult to uniquely untangle the source and propagation effects on the observed seismic data from underground nuclear explosions, even when large quantities of near-source, broadband data are available for analysis. This leads to uncertainties in our ability to quantify the nuclear seismic source function and, consequently the accuracy of seismic yield estimates for underground explosions. Extensive deterministic modeling analyses of the seismic data recorded from underground explosions at a variety of test sites have been conducted over the years and the results of these studies suggest that variations in the seismic source characteristics between test sites may be contributing to the observed differences in the magnitude/yield relations applicable at those sites. This contributes to our uncertainty in the determination of seismic yield estimates for explosions at previously uncalibrated test sites. In this paper we review issues involving the relationship of Nevada Test Site (NTS) source scaling laws to those at other sites. The Joint Verification Experiment (JVE) indicates that a magnitude (mb) bias (δmb) exists between the Semipalatinsk test site (STS) in the former Soviet Union (FSU) and the Nevada test site (NTS) in the United States. Generally this δmb is attributed to differential attenuation in the upper-mantle beneath the two test sites. This assumption results in rather large estimates of yield for large mb tunnel shots at Novaya Zemlya. A re-examination of the US testing experiments suggests that this δmb bias can partly be explained by anomalous NTS (Pahute) source characteristics. This interpretation is based on the modeling of US events at a number of test sites. Using a modified Haskell source description, we investigated the influence of the source Reduced Displacement Potential (RDP) parameters ψ ∞ , K and B by fitting short- and long-period data simultaneously, including the near-field body and surface waves. In general

  8. Self-Assembling Sup-porosity: The Effect On Fluid Flow And Seismic Wave Propagation

    Energy Technology Data Exchange (ETDEWEB)

    Pyrak-Nolte, Laura J. [Purdue University

    2013-04-27

    Fractures and joints in the field often contain debris within the void spaces. Debris originates from many different mechanisms: organic and/or inorganic chemical reactions/mineralization, sediment transport, formation of a fracture, mechanical weathering or combinations of these processes. In many cases, the presence of debris forms a sub-porosity within the fracture void space. This sub-porosity often is composed of material that differs from the fracture walls in mineralogy and morphology. The sub-porosity may partially fill voids that are on the order of hundreds of microns and thereby reduce the local porosity to lengths scales on the order of sub-microns to tens of microns. It is quite clear that a sub-porosity affects fracture porosity, permeability and storativity. What is not known is how the existence/formation of a sub-porosity affects seismic wave propagation and consequently our ability to probe changes in the subsurface caused by the formation or alteration of a sub-porosity. If seismic techniques are to be developed to monitor the injection and containment of phases in sequestration reservoirs or the propping of hydraulically induced fracture to enhance oil & gas production, it is important to understand how a sub-porosity within a fracture affects macroscopic seismic and hydraulic measurements. A sub-porosity will directly affect the interrelationship between the seismic and hydraulic properties of a fracture. This reports contains the results of the three main topics of research that were performed (1) to determine the effect of a sub-porosity composed of spherical grains on seismic wave propagation across fractures, (2) to determine the effect of biofilm growth in pores and between grains on seismic wave propagation in sediment, and (3) to determine the effect of the scale of observation (field-of-view) on monitoring alteration the pore space within a fracture caused by reactive flow. A brief summary of the results for each topic is contained in

  9. Investigation and analysis of SSI effects in seismic response of NPPs EMO and EBO

    International Nuclear Information System (INIS)

    Juhasova, E.

    1996-01-01

    This progress report outlines and describes the analysis and investigations of soil-structure interaction effects in seismic response of Bohunice and Mochovce nuclear power plants. The work carries out consists of theoretical-numerical analysis of soil-structure interaction and the description of the experimental results obtained so far. Investigations were performed for different soil conditions and recommendations were elaborated as to prepare and use long-term monitoring of vibration activity at the Bohunice NPP site

  10. Method of investigation, typologyand taxonomy of the basic data: navigating between seismic effects and historical contexts

    Directory of Open Access Journals (Sweden)

    E. Guidoboni

    2000-06-01

    Full Text Available This contribution presents the methods of research and filing of the historical data which are at the basis of the Catalogue of Strong Italian Earthquakes (CFTI3. Seen from the point of view of historical research, this is the first research carried out in Italy with continuous methods and objectives exceeding 15 years. Here the basic, historical and scientific sources that were used are presented, considering the peculiarity of these sources in relation to the testimonies of the seismic effects. In total, there are 25 780 recorded and analysed bibliographical entries, which have disclosed and located 33 150 seismic effects from the ancient world till 1997. The basic work has not only consisted of a meticulous indexing of the sources and texts, but also of a new outlining of the particular historical and cultural contexts, in which 605 analysed strong earthquakes occurred. Moreover, a small historical guide is presented to help orientate the user of the CFTI3. The complex history of the present-day Italian territory (which has passed for centuries under very different dominations and institutional structures has demanded a non-superficial analysis of these contexts in order to better trace and interpret the testimonies of the seismic effects on buildings as well as on the natural environment. The work, carried out with groups of specialised researchers, has also led to the compiling of a database capable of dynamically managing the interpreted information. The open structure of this work allows for the continuous data updating and expansion.

  11. Structure soil structure interaction effects: Seismic analysis of safety related collocated concrete structures

    International Nuclear Information System (INIS)

    Joshi, J.R.

    2000-01-01

    The Process, Purification and Stack Buildings are collocated safety related concrete shear wall structures with plan dimensions in excess of 100 feet. An important aspect of their seismic analysis was the determination of structure soil structure interaction (SSSI) effects, if any. The SSSI analysis of the Process Building, with one other building at a time, was performed with the SASSI computer code for up to 50 frequencies. Each combined model had about 1500 interaction nodes. Results of the SSSI analysis were compared with those from soil structure interaction (SSI) analysis of the individual buildings, done with ABAQUS and SASSI codes, for three parameters: peak accelerations, seismic forces and the in-structure floor response spectra (FRS). The results may be of wider interest due to the model size and the potential applicability to other deep soil layered sites. Results obtained from the ABAQUS analysis were consistently higher, as expected, than those from the SSI and SSSI analyses using the SASSI. The SSSI effect between the Process and Purification Buildings was not significant. The Process and Stack Building results demonstrated that under certain conditions a massive structure can have an observable effect on the seismic response of a smaller and less stiff structure

  12. Effects of Strike-Slip Fault Segmentation on Earthquake Energy and Seismic Hazard

    Science.gov (United States)

    Madden, E. H.; Cooke, M. L.; Savage, H. M.; McBeck, J.

    2014-12-01

    Many major strike-slip faults are segmented along strike, including those along plate boundaries in California and Turkey. Failure of distinct fault segments at depth may be the source of multiple pulses of seismic radiation observed for single earthquakes. However, how and when segmentation affects fault behavior and energy release is the basis of many outstanding questions related to the physics of faulting and seismic hazard. These include the probability for a single earthquake to rupture multiple fault segments and the effects of segmentation on earthquake magnitude, radiated seismic energy, and ground motions. Using numerical models, we quantify components of the earthquake energy budget, including the tectonic work acting externally on the system, the energy of internal rock strain, the energy required to overcome fault strength and initiate slip, the energy required to overcome frictional resistance during slip, and the radiated seismic energy. We compare the energy budgets of systems of two en echelon fault segments with various spacing that include both releasing and restraining steps. First, we allow the fault segments to fail simultaneously and capture the effects of segmentation geometry on the earthquake energy budget and on the efficiency with which applied displacement is accommodated. Assuming that higher efficiency correlates with higher probability for a single, larger earthquake, this approach has utility for assessing the seismic hazard of segmented faults. Second, we nucleate slip along a weak portion of one fault segment and let the quasi-static rupture propagate across the system. Allowing fractures to form near faults in these models shows that damage develops within releasing steps and promotes slip along the second fault, while damage develops outside of restraining steps and can prohibit slip along the second fault. Work is consumed in both the propagation of and frictional slip along these new fractures, impacting the energy available

  13. Probabilistic and Scenario Seismic and Liquefaction Hazard Analysis of the Mississippi Embayment Incorporating Nonlinear Site Effects

    Science.gov (United States)

    Cramer, C. H.; Dhar, M. S.

    2017-12-01

    The influence of deep sediment deposits of the Mississippi Embayment (ME) on the propagation of seismic waves is poorly understood and remains a major source of uncertainty for site response analysis. Many researchers have studied the effects of these deposits on seismic hazard of the area using available information at the time. In this study, we have used updated and newly available resources for seismic and liquefaction hazard analyses of the ME. We have developed an improved 3D geological model. Additionally, we used surface geological maps from Cupples and Van Arsdale (2013) to prepare liquefaction hazard maps. Both equivalent linear and nonlinear site response codes were used to develop site amplification distributions for use in generating hazard maps. The site amplification distributions are created using the Monte Carlo approach of Cramer et al. (2004, 2006) on a 0.1-degree grid. The 2014 National Seismic Hazard model and attenuation relations (Petersen et al., 2014) are used to prepare seismic hazard maps. Then liquefaction hazard maps are generated using liquefaction probability curves from Holzer (2011) and Cramer et al. (2015). Equivalent linear response (w/ increased precision, restricted nonlinear behavior with depth) shows similar hazard for the ME compared to nonlinear analysis (w/o pore pressure) results. At short periods nonlinear deamplification dominates the hazard, but at long periods resonance amplification dominates. The liquefaction hazard tends to be high in Holocene and late Pleistocene lowland sediments, even with lowered ground water levels, and low in Pleistocene loess of the uplands. Considering pore pressure effects in nonlinear site response analysis at a test site on the lowlands shows amplification of ground motion at short periods. PGA estimates from ME liquefaction and MMI observations are in the 0.25 to 0.4 g range. Our estimated M7.5 PGA hazard within 10 km of the fault can exceed this. Ground motion observations from

  14. Effects of Moat Wall Impact on the Seismic Response of Base Isolated Nuclear Power Plants

    International Nuclear Information System (INIS)

    Kim, Min Kyu; Kim, Jung Han; Mosqueda, Gilberto; Sarebanhab, Alireza

    2015-01-01

    The objectives of this study are to examine the effects of impact on the response of seismically isolated NPPs and identify characteristics of the isolation hardware and hard stop that minimize these effects. Considering variable distances to the hard stop and properties of the moat wall, the amplification in response is reported for acceleration and floor spectral accelerations at different points along the height of a NPP containment structure. Base isolation can be an effective strategy to protect critical facilities such as Nuclear Power Plants (NPPs) from the damaging effects of horizontal earthquake ground shaking. To be effective in reducing accelerations and deformations of the structure above, the seismic isolation bearings can be subjected to large displacements. In the case of an extreme earthquake, bearing displacements need to be limited by a hard stop in order to prevent failure of the bearings. Impact to the hard stop, which is often the moat wall at the basement level, is also of significant concern due to the potential for increased transfer of forces and amplification in response of the structural system, piping and other contents. However, the consequences of impact or factors important to mitigate its effects are not very well understood. The main findings of this study are related to modeling of NPP with moat wall in OpenSees and LSDyna as well as observations resulting from the parametric study of the performance of the NPP under different intensity levels of seismic excitations for different properties of the moat wall and bearings. • Variation in the isolator properties should be considered when examining seismic pounding. For BDBE even, 58.5 % cases result to the impact for lower bound properties while this value was 5.5 % for upper bound properties. Since the impact results are dependent to the assumed bearing properties, a better range of properties can be obtained from experimental testing of the bearing under large shear strains.

  15. Solar-terrestrial effect controls seismic activity to a large extent (Invited)

    Science.gov (United States)

    Duma, G.

    2010-12-01

    Several observational results and corresponding publications in the 20 century indicate that earthquakes in many regions happen systematically in dependence on the time of day and on the season as well. In the recent decade, studies on this topic have also been intensively performed at the Central Institute for Meteorology and Geodynamics (ZAMG), Vienna. Any natural effect on Earth which systematically appears at certain hours of the day or at a special season can solely be caused by a solar or lunar influence. And actually, statistic results on seismic activity reveal a correlation with the solar cycles. Examples of this seismic performance are shown. To gain more clarity about these effects, the three-hour magnetic index Kp, which characterizes the magnetic field disturbances, mainly caused by the solar particle radiation, the solar wind, was correlated with the seismic energy released by earthquakes over decades. Kp is determined from magnetic records of 13 observatories worldwide and continuously published by ISGI, France. It is demonstrated that a highly significant correlation between the geomagnetic index Kp and the annual seismic energy release in regions at latitudes between 35 and 60° N exists. Three regions of continental size were investigated, using the USGS (PDE) earthquake catalogue data. In the period 1974-2009 the Kp cycle periods range between 9 and 12 years, somewhat different to the sunspot number cycles of 11 years. Seismicity follows the Kp cycles with high coincidence. A detailed analysis of this correlation for N-America reveals, that the sum of released energy by earthquakes per year changes by a factor up to 100 with Kp. It is shown that during years of high Kp there happen e.g. 1 event M7, 4 events M6 and 30 events M5 per year, instead of only 10 events M5 in years with lowest Kp. Almost the same relation appears in other regions of continental size, with the same significance. The seismicity in S-America clearly follows the Kp cycles

  16. Air gun seismic effects on larvae and fry offshore; modeling and simulation

    International Nuclear Information System (INIS)

    Holmstroem, S.

    1993-04-01

    This report presents results from modeling and simulation of air gun seismic effects on fish and fry. A model has been developed to describe the behavior of fishes when a seismic ship is approaching and passes by the volume of residence of the fishes. The swimming capacity, the reaction to acoustic stimuli, the hearing threshold and the vertical distribution of the fishes have been included in the model. The model has been applied on cod fishes of length 25 and 350 mm. For realistic vertical distributions the big cod fishes will get away from the region near the boat where the probability for a mortal damage is greatest. 121 refs., 40 figs., 13 tabs

  17. Evaluating Seismic Site Effects at Cultural Heritage Sites in the Mediterranean Area

    Science.gov (United States)

    Imposa, S.; D'Amico, S.; Panzera, F.; Lombardo, G.; Grassi, S.; Betti, M.; Muscat, R.

    2017-12-01

    Present study concern integrated geophysical and numerical simulation aiming at evaluate the seismic vulnerability of cultural heritage sites. Non-invasive analysis targeted to characterize local site effects as well as dynamic properties of the structure were performed. Data were collected at several locations in the Maltese Archipelago (central Mediterranean) and in some historical buildings located in Catania (Sicily). In particular, passive seismic techniques and H/V data where used to derive 1D velocity models and amplification functions. The dynamic properties of a building are usually described through its natural frequency and the damping ratio. This latter is important in seismic design since it allows one to evaluate the ability of a structure to dissipate the vibration energy during an earthquake. The fundamental frequency of the investigated structure was obtained using ambient vibrations recorded by two or more sensors monitoring the motion at different locations in the building. Accordingly, the fundamental period of several Maltese Watchtowers and some historical buildings of Catania were obtained by computing the ratio between the amplitudes of the Fourier spectrum of horizontal (longitudinal and transverse) components recorded on the top and on the ground floors. Using ANSYS code, the modal analysis was performed to evaluate the first 50 vibration modes with the aim to check the activation of the modal masses and to assess the seismic vulnerability of the tower. The STRATA code was instead adopted in the Catania heritage buildings using as reference earthquake moderate to strong shocks that struck south-eastern Sicily. In most of the investigated buildings is was not possible to identify a single natural frequency but several oscillation modes. These results appear linked to the structural complexity of the edifices, their irregular plan shape and the presence of adjacent structures. The H/V outside the buildings were used to determine predominant

  18. An Effective Reservoir Parameter for Seismic Characterization of Organic Shale Reservoir

    Science.gov (United States)

    Zhao, Luanxiao; Qin, Xuan; Zhang, Jinqiang; Liu, Xiwu; Han, De-hua; Geng, Jianhua; Xiong, Yineng

    2017-12-01

    Sweet spots identification for unconventional shale reservoirs involves detection of organic-rich zones with abundant porosity. However, commonly used elastic attributes, such as P- and S-impedances, often show poor correlations with porosity and organic matter content separately and thus make the seismic characterization of sweet spots challenging. Based on an extensive analysis of worldwide laboratory database of core measurements, we find that P- and S-impedances exhibit much improved linear correlations with the sum of volume fraction of organic matter and porosity than the single parameter of organic matter volume fraction or porosity. Importantly, from the geological perspective, porosity in conjunction with organic matter content is also directly indicative of the total hydrocarbon content of shale resources plays. Consequently, we propose an effective reservoir parameter (ERP), the sum of volume fraction of organic matter and porosity, to bridge the gap between hydrocarbon accumulation and seismic measurements in organic shale reservoirs. ERP acts as the first-order factor in controlling the elastic properties as well as characterizing the hydrocarbon storage capacity of organic shale reservoirs. We also use rock physics modeling to demonstrate why there exists an improved linear correlation between elastic impedances and ERP. A case study in a shale gas reservoir illustrates that seismic-derived ERP can be effectively used to characterize the total gas content in place, which is also confirmed by the production well.

  19. Seismic Response of 3D Steel Buildings considering the Effect of PR Connections and Gravity Frames

    Directory of Open Access Journals (Sweden)

    Alfredo Reyes-Salazar

    2014-01-01

    Full Text Available The nonlinear seismic responses of 3D steel buildings with perimeter moment resisting frames (PMRF and interior gravity frames (IGF are studied explicitly considering the contribution of the IGF. The effect on the structural response of the stiffness of the beam-to-column connections of the IGF, which is usually neglected, is also studied. It is commonly believed that the flexibility of shear connections is negligible and that 2D models can be used to properly represent 3D real structures. The results of the study indicate, however, that the moments developed on columns of IGF can be considerable and that modeling buildings as plane frames may result in very conservative designs. The contribution of IGF to the lateral structural resistance may be significant. The contribution increases when their connections are assumed to be partially restrained (PR. The incremented participation of IGF when the stiffness of their connections is considered helps to counteract the no conservative effect that results in practice when lateral seismic loads are not considered in IGF while designing steel buildings with PMRF. Thus, if the structural system under consideration is used, the three-dimensional model should be used in seismic analysis and the IGF and the stiffness of their connections should be considered as part of the lateral resistance system.

  20. Seismic Response of 3D Steel Buildings considering the Effect of PR Connections and Gravity Frames

    Science.gov (United States)

    Haldar, Achintya; López-Barraza, Arturo; Rivera-Salas, J. Luz

    2014-01-01

    The nonlinear seismic responses of 3D steel buildings with perimeter moment resisting frames (PMRF) and interior gravity frames (IGF) are studied explicitly considering the contribution of the IGF. The effect on the structural response of the stiffness of the beam-to-column connections of the IGF, which is usually neglected, is also studied. It is commonly believed that the flexibility of shear connections is negligible and that 2D models can be used to properly represent 3D real structures. The results of the study indicate, however, that the moments developed on columns of IGF can be considerable and that modeling buildings as plane frames may result in very conservative designs. The contribution of IGF to the lateral structural resistance may be significant. The contribution increases when their connections are assumed to be partially restrained (PR). The incremented participation of IGF when the stiffness of their connections is considered helps to counteract the no conservative effect that results in practice when lateral seismic loads are not considered in IGF while designing steel buildings with PMRF. Thus, if the structural system under consideration is used, the three-dimensional model should be used in seismic analysis and the IGF and the stiffness of their connections should be considered as part of the lateral resistance system. PMID:24995357

  1. The Effectiveness of Seismic Isolation System for Nuclear Equipment

    International Nuclear Information System (INIS)

    Kim, Min-Kyu; Choun, Young-Sun; Seo, Jeong-Moon

    2005-04-01

    In this study, the Emergency Diesel Generator and Off-site Transformer were selected for isolation. For the selection of the most suitable base isolation system, the literature review and the numerical analysis were performed. For the decision of the parameter of isolation system, the sensitivity analysis was performed. Finally the conceptual design of each equipment was performed. In case of EDG, the Coil Spring and Viscous Damper system was selected for isolation system and 45% isolation effect was determined. For the OST, the FPS was selected and 69% isolation effect was determined

  2. The Effectiveness of Seismic Isolation System for Nuclear Equipment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min-Kyu; Choun, Young-Sun; Seo, Jeong-Moon

    2005-04-15

    In this study, the Emergency Diesel Generator and Off-site Transformer were selected for isolation. For the selection of the most suitable base isolation system, the literature review and the numerical analysis were performed. For the decision of the parameter of isolation system, the sensitivity analysis was performed. Finally the conceptual design of each equipment was performed. In case of EDG, the Coil Spring and Viscous Damper system was selected for isolation system and 45% isolation effect was determined. For the OST, the FPS was selected and 69% isolation effect was determined.

  3. Training for the seismic qualification utility group (SQUG) generic implementation procedure (GIP) for verification of seismic effects on nuclear power plant equipment

    International Nuclear Information System (INIS)

    Schaffstall, R.E.; Smith, N.P.; Baker, K.M.

    1993-01-01

    Resolution of USI A-46 was accomplished May, 1992 with the issuance of the SER for the GIP, Revision 2. The implementation of the resolution for the SQUG plants will be completed by 1996. Both the USNRC and the SQUG utilities have expended considerable resources to effect a common understanding that the effort has been worth the price. The Training Program developed to ensure that the efforts expended by the SQUG was indeed worth the price will be a major contributor in the success of the implementation. All of the older nuclear power plants in the United States now have an alternative standard to determine seismic resistance using experience data- a standard against which they can be evaluated and found seismically adequate to achieve and maintain a safe and reliable shutdown when subjected to strong motion earthquakes

  4. Effect of piles on the seismic response of mosques minarets

    Directory of Open Access Journals (Sweden)

    Mohamed Ahmed Abdel-Motaal

    2014-03-01

    Minaret (60.0-m height was studied to investigate the effects of soil stiffness, pile length, diameter, and arrangement, on the minaret and pile dynamic behavior. Comparison between study results and conventional analysis method is illustrated. Study results, discussion, and conclusion are given.

  5. Why Earthquake Effects are to be Reduced Conventional seismic ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 11. Learning Earthquake Design and Construction – 24. How to Reduce Earthquake Effects on Buildings? C V R Murty. Classroom Volume 10 Issue 11 November 2005 pp 89-92 ...

  6. Effective seismic acceleration measurements for low-cost Structural Health Monitoring

    Science.gov (United States)

    Pentaris, Fragkiskos; Makris, John P.

    2015-04-01

    There is increasing demand on cost effective Structural Health Monitoring systems for buildings as well as important and/or critical constructions. The front end for all these systems is the accelerometer. We present a comparative study of two low cost MEMS accelaration sensors against a very sensitive, high dynamic range strong motion accelerometer of force balance type but much more expensive. A real experiment was realized by deploying the three sesnors in a reinforced concrete building of the premises of TEI of Crete at Chania Crete, an earthquake prone region. The analysis of the collected accelararion data from many seismic events indicates that all sensors are able to efficiently reveal the seismic response of the construction in terms of PSD. Furthermore, it is shown that coherence diagrams between excitation and response of the building under study, depict structural characteristics but also the seismic energy distribution. This work is supported by the Archimedes III Program of the Ministry of Education of Greece, through the Operational Program "Educational and Lifelong Learning", in the framework of the project entitled "Interdisciplinary Multi-Scale Research of Earthquake Physics and Seismotectonics at the front of the Hellenic Arc (IMPACT-ARC)" and is co-financed by the European Union (European Social Fund) and Greek national funds.

  7. The Effect of Easy-Going Steel on KBF's Seismic Behavior

    Directory of Open Access Journals (Sweden)

    Mussa Mahmoudi

    2013-06-01

    Full Text Available The knee bracing steel frame (KBF is a new type of energy dissipating frame which enjoys exceptional ductility and lateral stiffness. Rather than the beam-column joint, one end of the diagonal brace in KBF is attached to the knee element. Indeed, the knee element as a hysteretic damper is designed and detailed to behave like a structural fuse by sustaining controlled inelastic deformations as well as by dissipating seismic energy, yet other parts and connections remain elastic. Simultaneously, the lower strength steel is utilized in knee element based on the general concept of easy-going steel (EGS. As the current paper takes into account the effect of easy going steel on KBF's response modification factor, several frames with similar dimensions but varying heights are designed based on the Iranian code of practice. For this purpose, initially the knee elements are substituted with the one made of EGS and subsequently the seismic parameters such as response modification factor and seismic performance levels are compared based on non-linear incremental dynamic analysis (IDA. The average values of response modification factor for these frames have been obtained 11.4 and 11.6 for KO and KE frames respectively. The results reveal that the frames' stiffness and ductility factor with EGS augments by 10% and 6% respectively.

  8. Effect of URM infills on seismic vulnerability of Indian code designed RC frame buildings

    Science.gov (United States)

    Haldar, Putul; Singh, Yogendra; Paul, D. K.

    2012-03-01

    Unreinforced Masonry (URM) is the most common partitioning material in framed buildings in India and many other countries. Although it is well-known that under lateral loading the behavior and modes of failure of the frame buildings change significantly due to infill-frame interaction, the general design practice is to treat infills as nonstructural elements and their stiffness, strength and interaction with the frame is often ignored, primarily because of difficulties in simulation and lack of modeling guidelines in design codes. The Indian Standard, like many other national codes, does not provide explicit insight into the anticipated performance and associated vulnerability of infilled frames. This paper presents an analytical study on the seismic performance and fragility analysis of Indian code-designed RC frame buildings with and without URM infills. Infills are modeled as diagonal struts as per ASCE 41 guidelines and various modes of failure are considered. HAZUS methodology along with nonlinear static analysis is used to compare the seismic vulnerability of bare and infilled frames. The comparative study suggests that URM infills result in a significant increase in the seismic vulnerability of RC frames and their effect needs to be properly incorporated in design codes.

  9. Effect of viscosity on seismic response of waste storage tanks

    International Nuclear Information System (INIS)

    Tang, Yu; Uras, R.A.; Chang, Yao-Wen.

    1992-06-01

    The dynamic response of liquid-storage tanks subjected to harmonic excitations and earthquake ground motions has been studied. A rigid tank of negligible mass, rigidly supported at the base having a diameter of 50 ft. and fluid height of 20.4 ft. was used in the computer analysis. The liquid is assumed to have a density of 1.5 g/ml. Viscosity values, μ = 60, 200, 100, and 10,000 cP, were used in the numerical analyses to study the effects of viscosity on sloshing wave height, impulsive and convective pressure on the tank wall, base shear and base moments. Harmonic excitations as well as earthquake ground motions were used as input motions. The harmonic excitations used in the analyses covers a wide range of frequencies, including both the resonant and non-resonant frequencies. Two earthquake motions were used. One matches the Newmark-Hall median response spectrum and is anchored at 0.24 g for a rock site with a damping of 2% and a time duration of 10 s. The other is the 1978 Tabas earthquake which had a peak ZPA of 0.81 g and a time duration of 29 s. A small tank, about 1/15 the size of the typical waste storage tank, was used in the harmonic excitation study to investigate the effect of viscosity on the response of liquid-storage tanks and how the viscosity effect is affected by the size of the storage tank. The results of this study show that for the typical waste storage tank subjected to earthquake motions, the effect of viscosity on sloshing wave height and impulsive and convective pressures is very small and can be neglected. For viscosity effect to become noticeable in the response of the typical waste storage tank, the waste viscosity must be greater than 10,000 cP. This value is far greater than the estimated viscosity value of the high level wastes, which may range from 60 to 200 cP for some tanks

  10. SISPRO: research and development on the seismic effects attenuation with depth for the seismic design of a long term nuclear waste disposal in the subsurface domain

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, D.; Bossu, R.; Le Piver, F.; Desveaux, F.; Seys, C.; Bouchez, J

    2001-07-01

    In the framework of the 1991/12/30 french law on the management of the nuclear industry waste, the French Atomic Energy Commission (C.E.A.) studies potential benefits against seismic risk of the subsurface domain for the design of an interim storage installation. Indeed, few damage has been observed on subsurface structures during large earthquakes which implied major destructive effects on surface buildings, as during the 1995 Kobe earthquake. However, knowledge on seismic design for subsurface facilities is mainly based on empirical know- how, without satisfactory scientific background which could allow characterization of any given site seismic wave attenuation with depth. The SISPRO program intends to fulfill this lack with two complementary research axis: data acquisition and analysis at several depths and in/on mountain topographies on one hand, accurate numerical modeling on the other hand. The latter will be useful for the establishment of a methodology able to predict seismic waves amplitude, depending on the geotechnical site characteristics and depth. Data analysis which has already been made, such as attenuation laws with several sites data and depth as a parameter, will be depicted. Numerical modeling is based on a 3-D finite differences method able to carry computation of synthetics in any kind of geology. A specific research program is devoted to the case when a topography is present. Numerical results show an attenuation which is smaller than the observed one. This implies that the introduction of a strong gradient in the surface layers properties is probably necessary. Perspectives of the SISPRO program until 2006 will be presented, such as strong motion modeling and how to take into account soil-structure interaction. (author)

  11. SISPRO: research and development on the seismic effects attenuation with depth for the seismic design of a long term nuclear waste disposal in the subsurface domain

    International Nuclear Information System (INIS)

    Rodriguez, D.; Bossu, R.; Le Piver, F.; Desveaux, F.; Seys, C.; Bouchez, J.

    2001-01-01

    In the framework of the 1991/12/30 french law on the management of the nuclear industry waste, the French Atomic Energy Commission (C.E.A.) studies potential benefits against seismic risk of the subsurface domain for the design of an interim storage installation. Indeed, few damage has been observed on subsurface structures during large earthquakes which implied major destructive effects on surface buildings, as during the 1995 Kobe earthquake. However, knowledge on seismic design for subsurface facilities is mainly based on empirical know- how, without satisfactory scientific background which could allow characterization of any given site seismic wave attenuation with depth. The SISPRO program intends to fulfill this lack with two complementary research axis: data acquisition and analysis at several depths and in/on mountain topographies on one hand, accurate numerical modeling on the other hand. The latter will be useful for the establishment of a methodology able to predict seismic waves amplitude, depending on the geotechnical site characteristics and depth. Data analysis which has already been made, such as attenuation laws with several sites data and depth as a parameter, will be depicted. Numerical modeling is based on a 3-D finite differences method able to carry computation of synthetics in any kind of geology. A specific research program is devoted to the case when a topography is present. Numerical results show an attenuation which is smaller than the observed one. This implies that the introduction of a strong gradient in the surface layers properties is probably necessary. Perspectives of the SISPRO program until 2006 will be presented, such as strong motion modeling and how to take into account soil-structure interaction. (author)

  12. Effects of fluid communications between fluid volumes on the seismic behaviour of nuclear breeder reactor internals

    International Nuclear Information System (INIS)

    Durandet, E.; Gibert, R.J.

    1987-01-01

    The internal structures of a breeder reactor as SUPERPHENIX are mainly axisymmetrial shells separated by fluid volumes which are connected by small communications holes. These communications can destroy the axisymmetry of the problem and their effects on the inertial terms due to the fluid are important. An equivalent axisymmetrical element based on a local tridimensional solution in the vicinity of the fluid communication is defined. An axisymmetrical modelization using this type of element is built in order to calculate the horizontal seismic behaviour of the reactor internals. The effect due to three typical fluid communications are studied and compared. (orig.)

  13. The influence of backfill on seismicity

    CSIR Research Space (South Africa)

    Hemp, DA

    1990-09-01

    Full Text Available , that the seismicity has been reduced in areas where backfill had been placed. A factor complicating the evaluation of backfill on seismicity is the effect of geological structures on seismicity....

  14. Centrifuge modelling of seismic soil structure interaction effects

    International Nuclear Information System (INIS)

    Ghosh, B.; Madabhushi, S.P.G.

    2007-01-01

    Proper understanding of the role of unbounded soil in the evaluation of dynamic soil structure interaction (SSI) problem is very important for structures used in the nuclear industry. In this paper, the results from a series of dynamic centrifuge tests are reported. These tests were performed on different types of soil stratifications supporting a rigid containment structure. Test results indicate that accelerations transmitted to the structure's base are dependent on the stiffness degradation in the supporting soil. Steady build up of excess pore pressure leads to softening of the soil, which decreases the shear modulus and shear strength and subsequently changes the dynamic responses. It is also shown that the presence of the structure reduces the translational component of the input base motion and induces rocking of the structure. The test results are compared with some standard formulae used for evaluating interaction in the various building codes. It was concluded that the dynamic shear modulus values used should be representative of the site conditions and can vary dramatically due to softening. Damping values used are still very uncertain and contain many factors, which cannot be accounted in the experiments. It is emphasized that simplified design processes are important to gain an insight into the behaviour of the physical mechanism but for a complete understanding of the SSI effects sophisticated methods are necessary to account for non-linear behaviour of the soil material

  15. Effects of seismic lines on the abundance of breeding birds in the Kendall Island Bird Sanctuary, Northwest Territories, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Ashenhurst, A.R.; Hannon, S.J. [Alberta Univ., Edmonton, AB (Canada). Dept. of Biological Sciences

    2008-06-15

    The effects of oil and gas exploration activities on bird abundance in the Arctic were investigated. The study examined the impacts of new and oil visible seismic lines within the Kendall Island Bird Sanctuary on the abundance of breeding passerines, Lapland longspur, common redpoll, American tree sparrow, and red-necked phalarope in upland tundra region and sedge-willow habitats. Results of the study showed that the effects on abundance with newer seismic lines were not statistically significant for most groups of birds. However, more birds were seen on reference transects than on seismic lines. The seismic lines had a significant impact on passerines grouped in upland tundra, as well as for sparrows in sedge and willows. Along older seismic lines, passerine abundance was lower than on reference transects in upland tundra. The study demonstrated that seismic lines created between 10 and 30 years ago had persistent vegetative changes that have reduced bird abundance. It was concluded that although the birds were not avoiding lines, some birds appeared to have increased the size of their territories in order to compensate for vegetative changes. 34 refs., 4 tabs.

  16. Effects of disturbance associated with seismic exploration for oil and gas reserves in coastal marshes

    Science.gov (United States)

    Howard, Rebecca J.; Wells, Christopher J.; Michot, Thomas C.; Johnson, Darren J.

    2014-01-01

    Anthropogenic disturbances in wetland ecosystems can alter the composition and structure of plant assemblages and affect system functions. Extensive oil and gas extraction has occurred in wetland habitats along the northern Gulf of Mexico coast since the early 1900s. Activities involved with three-dimensional (3D) seismic exploration for these resources cause various disturbances to vegetation and soils. We documented the impact of a 3D seismic survey in coastal marshes in Louisiana, USA, along transects established before exploration began. Two semi-impounded marshes dominated by Spartina patens were in the area surveyed. Vegetation, soil, and water physicochemical data were collected before the survey, about 6 weeks following its completion, and every 3 months thereafter for 2 years. Soil cores for seed bank emergence experiments were also collected. Maximum vegetation height at impact sites was reduced in both marshes 6 weeks following the survey. In one marsh, total vegetation cover was also reduced, and dead vegetation cover increased, at impact sites 6 weeks after the survey. These effects, however, did not persist 3 months later. No effects on soil or water properties were identified. The total number of seeds that germinated during greenhouse studies increased at impact sites 5 months following the survey in both marshes. Although some seed bank effects persisted 1 year, these effects were not reflected in standing vegetation. The marshes studied were therefore resilient to the impacts resulting from 3D seismic exploration because vegetation responses were short term in that they could not be identified a few months following survey completion.

  17. Effects of Disturbance Associated With Seismic Exploration for Oil and Gas Reserves in Coastal Marshes

    Science.gov (United States)

    Howard, Rebecca J.; Wells, Christopher J.; Michot, Thomas C.; Johnson, Darren J.

    2014-07-01

    Anthropogenic disturbances in wetland ecosystems can alter the composition and structure of plant assemblages and affect system functions. Extensive oil and gas extraction has occurred in wetland habitats along the northern Gulf of Mexico coast since the early 1900s. Activities involved with three-dimensional (3D) seismic exploration for these resources cause various disturbances to vegetation and soils. We documented the impact of a 3D seismic survey in coastal marshes in Louisiana, USA, along transects established before exploration began. Two semi-impounded marshes dominated by Spartina patens were in the area surveyed. Vegetation, soil, and water physicochemical data were collected before the survey, about 6 weeks following its completion, and every 3 months thereafter for 2 years. Soil cores for seed bank emergence experiments were also collected. Maximum vegetation height at impact sites was reduced in both marshes 6 weeks following the survey. In one marsh, total vegetation cover was also reduced, and dead vegetation cover increased, at impact sites 6 weeks after the survey. These effects, however, did not persist 3 months later. No effects on soil or water properties were identified. The total number of seeds that germinated during greenhouse studies increased at impact sites 5 months following the survey in both marshes. Although some seed bank effects persisted 1 year, these effects were not reflected in standing vegetation. The marshes studied were therefore resilient to the impacts resulting from 3D seismic exploration because vegetation responses were short term in that they could not be identified a few months following survey completion.

  18. Impacting effects of seismic loading in feeder pipes of PHWR power plants

    International Nuclear Information System (INIS)

    Kumar, R.

    1996-01-01

    The core of a pressurized heavy water reactor (PHWR) consists of a large number of fuel channels. These fuel channels are connected to the feeder pipes through which the heavy water flows and transports heat from the reactor core to the steam generators. The feeder pipes are several hundreds in number. They run close to each other with small gaps and have several bends. Thus they represent a complex piping system. Under seismic loading, the adjacent feeder pipes may impact each other. In this paper a simplified procedure has been established to assess such impacting effects. The results of the proposed analysis include bending moment and impact force, which provide the stresses due to impacting effects. These results are plotted in nondimensional form so that they could be utilized for any set of feeder pipes. The procedure used for studying the impacting effects includes seismic analysis of individual feeder pipes without impacting effects, selection of pipes for impact analysis, and estimating their maximum impact velocity. Based on the static and dynamic characteristics of the selected feeder pipes, the maximum bending moment, impact force, and stresses are obtained. The results of this study are useful for quick evaluation of the impacting effects in feeder pipes

  19. Comparison of Effective Medium Schemes For Seismic Velocities in Cracked Anisotropic Rock

    Science.gov (United States)

    Morshed, S.; Chesnokov, E.

    2017-12-01

    Understanding of elastic properties of reservoir rock is necessary for meaningful interpretation and analysis of seismic measurements. The elastic properties of a rock are controlled by the microstructural properties such as mineralogical composition, pore and crack distribution, texture and pore connectivity. However, seismic scale is much larger than microstructure scale. Understanding of macroscopic properties at relevant seismic scale (e.g. borehole sonic data) comes from effective medium theory (EMT). However, most of the effective medium theories fail at high crack density as the interactions of strain fields of the cracks can't be ignored. We compare major EMT schemes from low to high crack density. While at low crack density all method gives similar results, at high crack density they differ significantly. Then, we focus on generalized singular approximation (GSA) and effective field (EF) method as they allow cracks beyond the limit of dilute concentrations. Additionally, we use grain contact (GC) method to examine the stiffness constants of the rock matrix. We prepare simple models of a multiphase media containing low to high concentrations of isolated pores. Randomly oriented spherical pores and horizontally oriented ellipsoidal (aspect ratio =0.1) pores have been considered. For isolated spherical pores, all the three methods show exactly same or similar results. However, inclusion interactions are different in different directions in case of horizontal ellipsoidal pores and individual stiffness constants differ greatly from one method to another at different crack density. Stiffness constants remain consistent in GSA method whereas some components become unusual in EF method at a higher crack density (>0.15). Finally, we applied GSA method to interpret ultrasonic velocities of core samples. Mineralogical composition from X-ray diffraction (XRD) data and lab measured porosity data have been utilized. Both compressional and shear wave velocities from GSA

  20. Effects of the vessel core seismic interaction for a fast reactor

    International Nuclear Information System (INIS)

    Martelli, A.; Maresca, G.

    1983-01-01

    This report describes the features and the results of the analysis carried out in collaboration between ENEA and NIRA for evaluating the effects of the vessel core dynamic interaction in case of safe shutdown earthquake, both in absence and in presence of one or two restraint plates inserted in the tank close to the middle and or top planes for limiting the core seismic motion. Such analysis, although carried out making use of preliminary data, contributed to the recent ENEA decision of applying a core restraint close to the core element top

  1. Several problems of cumulative effective mass fraction in anti-seismic analysis

    International Nuclear Information System (INIS)

    Wang Wei; Sheng Feng; Li Hailong; Wen Jing; Luan Lin

    2005-01-01

    Cumulative Effective Mass Fraction (CEMF) is one of important items which sign the accuracy in antiseismic analysis. Based on the primary theories of CEMF, the paper show the influence of CEMF on the accuracy in antiseismic analysis. Moreover, some advices and ways are given to solve common problems in antiseismic analysis, such as how to increase CEMF, how to avoid the mass's loss because of the torsional frequency's being close to the frequency corresponding to the peak of seismic response spectrum, how to avoid the mass's loss because of the constraints, and so on. (authors)

  2. Martian seismicity

    International Nuclear Information System (INIS)

    Goins, N.R.; Lazarewicz, A.R.

    1979-01-01

    During the Viking mission to Mars, the seismometer on Lander II collected approximately 0.24 Earth years of observations data, excluding periods of time dominated by wind-induced Lander vibration. The ''quiet-time'' data set contains no confirmed seismic events. A proper assessment of the significance of this fact requires quantitative estimates of the expected detection rate of the Viking seismometer. The first step is to calculate the minimum magnitude event detectable at a given distance, including the effects of geometric spreading, anelastic attenuation, seismic signal duration, seismometer frequency response, and possible poor ground coupling. Assuming various numerical quantities and a Martian seismic activity comparable to that of intraplate earthquakes, the appropriate integral gives an expected annual detection rate of 10 events, nearly all of which are local. Thus only two to three events would be expected in the observational period presently on hand and the lack of observed events is not in gross contradiction to reasonable expectations. Given the same assumptions, a seismometer 20 times more sensitive than the present instrument would be expected to detect about 120 events annually

  3. Effect of frequency and flexibility ratio on the seismic response of deep tunnels

    Directory of Open Access Journals (Sweden)

    Eimar Sandoval

    2017-06-01

    Full Text Available Two-dimensional dynamic numerical analyses have been conducted, using FLAC 7.0, to evaluate the seismic response of underground structures located far from the seismic source, placed in either linear-elastic or nonlinear elastoplastic ground. The interaction between the ground and deep circular tunnels with a tied interface is considered. For the simulations, it is assumed that the liner remains in its elastic regime, and plane strain conditions apply to any cross section perpendicular to the tunnel axis. An elastoplastic constitutive model is implemented in FLAC to simulate the nonlinear ground. The effect of input frequency and relative stiffness between the liner and the ground, on the seismic response of tunnels, is evaluated. The response is studied in terms of distortions normalized with respect to those of the free field, and load demand (axial forces and bending moments in the liner. In all cases, i.e. for linear-elastic and nonlinear ground models, the results show negligible effect of the input frequency on the distortions of the cross section, for input frequencies smaller than 5 Hz; that is for ratios between the wave length and the tunnel opening (λ/D larger than ten for linear-elastic and nine for nonlinear ground. Larger normalized distortions are obtained for the nonlinear than for the linear-elastic ground, for the same relative stiffness, with differences increasing as the tunnel becomes more flexible, or when the amplitude of the dynamic input shear stress increases. It has been found that normalized distortions for the nonlinear ground do not follow a unique relationship, as it happens for the linear-elastic ground, but increase as the amplitude of the dynamic input increases. The loading in the liner decreases as the structure becomes more flexible with respect to the ground, and is smaller for a tunnel placed in a stiffer nonlinear ground than in a softer nonlinear ground, for the same flexibility ratio.

  4. Chemical and isotopic seismic precursory signatures in deep groundwater: Cause and effect

    International Nuclear Information System (INIS)

    Reddy, D.V.; Nagabhushanam, P.

    2012-01-01

    Exploratory hydrochemical studies were initiated in Koyna, India, to examine the chemical changes in the deep groundwater due to seismic activity, 2 months before the occurrence of a M 5.1 earthquake on 14th March 2005. A few deep wells (100–250 m), out of a dozen, recorded hydrochemical anomalies induced by this earthquake, and the anomalies continued for the next 3 months. Periodical hydrochemical data of one of the wells indicated a linear increase in Cl − , SO 4 2- , F − and depleted δ 18 O from August 2006 to March 2009, though there is no long term change in groundwater level (except short duration seasonal change). The observed linear change is hypothesised as an effect of aquifer response to seismic stress related to an impending earthquake of M ⩾ 5. The observed temporal change in different chemical concentrations projected linearly to the levels of March 2005 and estimated the time of the impending earthquake (the same as that of March 2005 event) as 2011/12. Further, the time projection also made based on exponential increase in hydrochemistry after 3/2009, advanced the possible time window to 2010/11. This hypothesis was realized on 12 December 2009 with an earthquake of M 5.1. Even the simple arithmetic mean of the 45-a earthquake (M > 5) history of Koyna indicates a recurrence time of ∼5.4 a. To account for the observed temporal hydrochemical changes, a model, based on mixing of two aquifer waters caused by seismic stress, was proposed. Hourly monitoring of electrical conductivity (EC) of groundwater also recorded conductivity changes induced by the M 5.1 earthquake on 12th December 2009. A very important observation that emerges from this study is that the cyclic change in subsurface stress leads to earthquakes. Continuous monitoring of EC may be helpful in visualizing the effect of tectonic forces on groundwater chemistry.

  5. Effect of tidal triggering on seismicity in Taiwan revealed by the empirical mode decomposition method

    Directory of Open Access Journals (Sweden)

    H.-J. Chen

    2012-07-01

    Full Text Available The effect of tidal triggering on earthquake occurrence has been controversial for many years. This study considered earthquakes that occurred near Taiwan between 1973 and 2008. Because earthquake data are nonlinear and non-stationary, we applied the empirical mode decomposition (EMD method to analyze the temporal variations in the number of daily earthquakes to investigate the effect of tidal triggering. We compared the results obtained from the non-declustered catalog with those from two kinds of declustered catalogs and discuss the aftershock effect on the EMD-based analysis. We also investigated stacking the data based on in-phase phenomena of theoretical Earth tides with statistical significance tests. Our results show that the effects of tidal triggering, particularly the lunar tidal effect, can be extracted from the raw seismicity data using the approach proposed here. Our results suggest that the lunar tidal force is likely a factor in the triggering of earthquakes.

  6. The effect of seismic motion characteristics on the inelastic response reduction of cylindrical shell structures

    International Nuclear Information System (INIS)

    Hagiwara, Y.; Yamamoto, K.; Akiyama, H.

    1993-01-01

    Reactor vessels of FBR are cylindrical shell structures, whose critical failure mode during earthquakes is plastic buckling in shear or bending mode. In buckling prevention of the vessels, it is of primary importance to realistically evaluate the plastic response reduction effect in the pre-buckling stage. Though the authors have already proposed a empirical formula to estimate the response reduction effect, the formula depends only on the pre-buckling ductility factor in the evaluation for the purpose of easy design practice. In this study, the effect of seismic motion characteristics on the response reduction effect was investigated both experimentally and numerically, and a improved version of the empirical expression of the reduction factor was proposed. In this new method, the response reduction effect is evaluated by an initial acceleration amplification factor in addition to the ductility of structures. (author)

  7. The Seismic Fragility Evaluation of an Offsite Transformer according to Aging Effects

    International Nuclear Information System (INIS)

    Kim, Min Kyu; Choi, In Kil

    2008-01-01

    A seismic fragility analysis was performed, especially for an aged electric power transmission system, in this study. A real electric transformer system for Korean Nuclear Power Plants was selected for the seismic fragility evaluation. In the case of a seismic fragility analysis we should use design material properties and conditions. However material properties and environmental conditions of most structures and equipment are changed according to a lapse of time. Aging conditions greatly affect the integrity of the structures and equipment at NPP sites, but it is very difficult to estimate them qualitatively. Integrity of an anchor bolt system was considered with the aging conditions for an electric transformer system. At first, a seismic fragility analysis was performed for a fine condition for an electric transformer system. After that, a seismic fragility analysis according to the fastener of an anchor bolt system was conducted. This study showed that a looser anchor bolt creates seismic responses and seismic fragility changes of more 10%

  8. A comparison of experimental and theoretical investigations of embedment effects on seismic response

    International Nuclear Information System (INIS)

    Hadjian, A.H.; Howard, G.E.; Smith, C.B.

    1975-01-01

    A research program has been conducted to both gain insight into the effects of embedment on the seismic response of nuclear power plant containment structures and to verify current analytical methods for the prediction of their seismic response. Tests were first performed on small wooden cylinders, rectangles, and cubes using a shake table to conduct parametric studies in the effects of geometry, height to diameter ratio, and amount of embedment. The effects of the shake table were isolated by repeating the tests on specimens buried in actual soils. Next, a larger-scale concrete model (height - 2 meters, weight - 1700 kg) was fabricated and tested at varying embedments using an eccentric mass structural vibrator. Additionally, an attempt was made to correlate the experimental results with simplified and finite element models that included both embedment and nonlinear effects. The embedment effects in the simplified model were taken as an increase of the impedance coefficients used for structures on the ground. Nonlinear effects were incorporated by calculating strain levels and using published data to adjust the site soil parameters. The results reported are applicable to cases where the foundation materials under and around the structure are similar. It was found that when very law strains (10 -5 -10 -3 %) were applied, the embedment effect was progressively more important as the depth-to-diameter ratio increased. However, with layer strain (10 -2 -10 -1 %) where the response of the cylinder was in the range of 0.75 to 1.25 g's, the effect of embedment was negligible up to a depth-to-diameter ratio of 0.5. This phenomenon can be explained by the plastic deformation of the surrounding soil and loss of effective contact with the cylinder

  9. 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)

  10. Seismic analysis and testing of nuclear power plants

    International Nuclear Information System (INIS)

    1979-01-01

    The following subjects are discussed in this guide: General Recommendations for seismic classification, loading combinations and allowable limits; seismic analysis methods; implications for seismic design; seismic testing and qualification; seismic instrumentation; modelling techniques; material property characterization; seismic response of soil deposits and earth structures; liquefaction and ground failure; slope stability; sloshing effects in water pools; qualification testing by means of the transport vehicle

  11. Effects of support masses on seismic response of piping and supports

    International Nuclear Information System (INIS)

    Iotti, R.C.; Dinkevich, S.

    1985-01-01

    A special methodology is presented for quantitatively predicting when the effect of piping restraint masses is significant and should be explicitly considered in piping seismic analyses which use the response spectrum method. It is concluded that the effect of support mass in the unrestrained direction is to increase piping and support responses by a percentage no larger than twice the ratio of the support to the pipe-supported span mass. In the restrained direction the mass of the support significantly reduces its dynamic stiffness so that for low support stiffnesses and relatively large mass the support can act as an amplifier of vibration. The dynamic effect, however, is negligible for very stiff supports. (orig.)

  12. Improved Simplified Methods for Effective Seismic Analysis and Design of Isolated and Damped Bridges in Western and Eastern North America

    Science.gov (United States)

    Koval, Viacheslav

    The seismic design provisions of the CSA-S6 Canadian Highway Bridge Design Code and the AASHTO LRFD Seismic Bridge Design Specifications have been developed primarily based on historical earthquake events that have occurred along the west coast of North America. For the design of seismic isolation systems, these codes include simplified analysis and design methods. The appropriateness and range of application of these methods are investigated through extensive parametric nonlinear time history analyses in this thesis. It was found that there is a need to adjust existing design guidelines to better capture the expected nonlinear response of isolated bridges. For isolated bridges located in eastern North America, new damping coefficients are proposed. The applicability limits of the code-based simplified methods have been redefined to ensure that the modified method will lead to conservative results and that a wider range of seismically isolated bridges can be covered by this method. The possibility of further improving current simplified code methods was also examined. By transforming the quantity of allocated energy into a displacement contribution, an idealized analytical solution is proposed as a new simplified design method. This method realistically reflects the effects of ground-motion and system design parameters, including the effects of a drifted oscillation center. The proposed method is therefore more appropriate than current existing simplified methods and can be applicable to isolation systems exhibiting a wider range of properties. A multi-level-hazard performance matrix has been adopted by different seismic provisions worldwide and will be incorporated into the new edition of the Canadian CSA-S6-14 Bridge Design code. However, the combined effect and optimal use of isolation and supplemental damping devices in bridges have not been fully exploited yet to achieve enhanced performance under different levels of seismic hazard. A novel Dual-Level Seismic

  13. The effect of material properties on the seismic performance of Arch Dams

    Directory of Open Access Journals (Sweden)

    B. Sevim

    2011-08-01

    Full Text Available The paper investigates the effect of material properties on the seismic performance of arch dam-reservoir-foundation interaction systems based on the Lagrangian approach using demand-capacity ratios. Type-5 arch dam is selected as a numerical application. The linear time history analyses of the arch dam-reservoir-foundation interaction system are carried out for different material properties. The foundation is taken into account as massless; behaviour of the reservoir is assumed to be linearly elastic, inviscid and irrotational. The north-south component of the Erzincan earthquake in 1992 is chosen as a ground motion. Dynamic equations of motions obtained from 3-D finite element modelling of the coupled system are solved by using the Newmark integration algorithm. The damage levels of the coupled system for the different material properties are demonstrated by using demand-capacity ratios and cumulative inelastic durations. The time histories and maximum values of the displacements and principal stresses, and performance curves, are obtained from linear analyses. It is clearly seen from the study that the different material properties affect the seismic behaviour of the dam.

  14. Electric effects induced by artificial seismic sources at Somma-Vesuvius volcano

    Directory of Open Access Journals (Sweden)

    Rosa Di Maio

    2013-11-01

    Full Text Available In this paper, we present a series of self-potential measurements at Somma-Vesuvius volcanic area acquired in conjunction with an active seismic tomography survey. The aim of our study is both to provide further confirmation to the occurrence of seismo-electric coupling and to identify sites suitable for self-potential signal monitoring at Somma-Vesuvius district. The data, which were collected along two perpendicular dipoles, show significant changes on the natural electric field pattern. These variations, attributable to electrokinetic processes triggered by the artificial seismic waves, were observed after explosions occurred at a distance less than 5 km from the SP dipole arrays. In particular, we found that the NW-SE component of the natural electric field was more sensible to the shots than the NE-SW one, and the major effects did not correspond to the nearest shots. Such evidences were interpreted considering the underground electrical properties as deduced by previous detailed resistivity and self-potential surveys performed in the study area.

  15. WAVE EQUATION DATUMING TO CORRECT TOPOGRAPHY EFFECT ON FOOTHILL SEISMIC DATA

    Directory of Open Access Journals (Sweden)

    Montes Vides Luis Alfredo

    2005-08-01

    Full Text Available The current seismic processing applies Static Corrections to overcome the effects associated to rough topography, based in the assumption that velocity in near surface is lower than in the substratum, which force going up rays travel near to vertical. However, when the velocity contrast between these layers is not large enough, the trajectory of the up going rays deviate from vertical raveling the reflectors erroneously. A better alternative to correct this is to continue the wave field to a datum, because it does not assume vertical ray trajectory and solves the acoustic wave equation to extrapolate sources and receivers. The Kirchhoff approach was tested in synthetic shots continuing their wave field to a datum and finally it was applied instead of Static Corrections in real data acquired in foothill zones. First shot and receiver gathers were downward continued to the base of weathering layer and later upward continued to a final flat datum. Comparing the obtained results we observed that continuation approach provides a noticeable enhancement of reflectors in seismic records, displaying a better continuity of the reflectors and an increment in frequency content.

  16. Seismic and dynamic qualification methods

    International Nuclear Information System (INIS)

    Lin, C.W.

    1985-01-01

    This book presents the papers given at a conference on seismic effects on nuclear power plants. Topics considered at the conference included seismic qualification of equipment, multifrequency test methodologies, damping in piping systems, the amplification factor, thermal insulation, welded joints, and response factors for seismic risk analysis of piping

  17. Effects of Attenuation of Gas Hydrate-bearing Sediments on Seismic Data: Example from Mallik, Northwest Territories, Canada

    Science.gov (United States)

    Bellefleur, G.; Riedel, M.; Brent, T.

    2007-05-01

    Wave attenuation is an important physical property of hydrate-bearing sediments that is rarely taken into account in site characterization with seismic data. We present a field example showing improved images of hydrate- bearing sediments on seismic data after compensation of attenuation effects. Compressional quality factors (Q) are estimated from zero-offset Vertical Seismic Profiling data acquired at Mallik, Northwest Territories, Canada. During the last 10 years, two internationally-partnered research drilling programs have intersected three major intervals of sub-permafrost gas hydrates at Mallik, and have successfully extracted core samples containing significant amount of gas hydrates. Individual gas hydrate intervals are up to 40m in thickness and are characterized by high in situ gas hydrate saturation, sometimes exceeding 80% of pore volume of unconsolidated clastic sediments having average porosities ranging from 25% to 40%. The Q-factors obtained from the VSP data demonstrate significant wave attenuation for permafrost and hydrate- bearing sediments. These results are in agreement with previous attenuation estimates from sonic logs and crosshole data at different frequency intervals. The Q-factors obtained from VSP data were used to compensate attenuation effects on surface 3D seismic data acquired over the Mallik gas hydrate research wells. Intervals of gas hydrate on surface seismic data are characterized by strong reflectivity and effects from attenuation are not perceptible from a simple visual inspection of the data. However, the application of an inverse Q-filter increases the resolution of the data and improves correlation with log data, particularly for the shallowest gas hydrate interval. Compensation of the attenuation effects of the permafrost likely explains most of the improvements for the shallow gas hydrate zone. Our results show that characterization of the Mallik gas hydrates with seismic data not corrected for attenuation would tend to

  18. Memory effect in M ≥ 6 earthquakes of South-North Seismic Belt, Mainland China

    Science.gov (United States)

    Wang, Jeen-Hwa

    2013-07-01

    The M ≥ 6 earthquakes occurred in the South-North Seismic Belt, Mainland China, during 1901-2008 are taken to study the possible existence of memory effect in large earthquakes. The fluctuation analysis technique is applied to analyze the sequences of earthquake magnitude and inter-event time represented in the natural time domain. Calculated results show that the exponents of scaling law of fluctuation versus window length are less than 0.5 for the sequences of earthquake magnitude and inter-event time. The migration of earthquakes in study is taken to discuss the possible correlation between events. The phase portraits of two sequent magnitudes and two sequent inter-event times are also applied to explore if large (or small) earthquakes are followed by large (or small) events. Together with all kinds of given information, we conclude that the earthquakes in study is short-term correlated and thus the short-term memory effect would be operative.

  19. Study of blasting seismic effects of underground powerhouse of pumped storage project in granite condition

    Science.gov (United States)

    Wan, Sheng; Li, Hui

    2018-03-01

    Though the test of blasting vibration, the blasting seismic wave propagation laws in southern granite pumped storage power project are studied. Attenuation coefficient of seismic wave and factors coefficient are acquired by the method of least squares regression analysis according to Sadaovsky empirical formula, and the empirical formula of seismic wave is obtained. This paper mainly discusses on the test of blasting vibration and the procedure of calculation. Our practice might as well serve as a reference for similar projects to come.

  20. Ascertaining Grain Scale Effects Of Seismic Or Aseismic Stimulation Upon Strength Of Near Surface Geological Materials

    Directory of Open Access Journals (Sweden)

    Bilal Hassan

    2017-02-01

    Full Text Available Certain peculiarities of inelastic nonlinearity of unconsolidated near surface periodically stressed granular media contributed at micro- scale are investigated to ascertain possible anomalous time dependent strength behavior macro-effects with geotechnicalgeo-environmental implications. Comparative examination of ultrasonic P- and S-wave repeatable displacement response wave-forms in time records and spectra of pulse stimulated both confined dry and fully saturated ceramic grains analogue endorsable by pertinent theory is performed. Examination is primarily aimed at both understanding connectivity of louder response generated by seemingly unobtrusive quieter seismic and aseismic events in granular sediments. Secondarily results impart an enhanced conceptual substantiation of some previously disseminated andor published results. The results hint certain persistive time and frequency restricted occurrences vouching vital insights. It could be unambiguously clarified that subtle acoustic emission andor stick-slip type micro events in stimulated i.e. seismic or aseismic unconsolidated granular sediments do occur. When spread over time andor space their cumulated effect may be capable of altering granular material macro strength behavior. It is clearly deducible from resonant type spectral results that material fragmentation or force chain formation type phenomenon occurs possibly due to macro-scale friction mobilization by grain-scale events. It is further speculated that invisible high frequency events may irreversibly alter grain-scale surface properties andor intergranular friction as pseudo enhanced elasticity type effect more elusive with saturation. An assessment of an examined temporal distribution of grain-scale stick-slip type events when stimulated by P- and S-wave modes is posited to be non-identical. The former as if is retardation associated while the latter relaxation type in a characteristic sense. Presented result forms combined not

  1. Probabilistic seismic hazard estimates incorporating site effects - An example from Indiana, U.S.A

    Science.gov (United States)

    Hasse, J.S.; Park, C.H.; Nowack, R.L.; Hill, J.R.

    2010-01-01

    The U.S. Geological Survey (USGS) has published probabilistic earthquake hazard maps for the United States based on current knowledge of past earthquake activity and geological constraints on earthquake potential. These maps for the central and eastern United States assume standard site conditions with Swave velocities of 760 m/s in the top 30 m. For urban and infrastructure planning and long-term budgeting, the public is interested in similar probabilistic seismic hazard maps that take into account near-surface geological materials. We have implemented a probabilistic method for incorporating site effects into the USGS seismic hazard analysis that takes into account the first-order effects of the surface geologic conditions. The thicknesses of sediments, which play a large role in amplification, were derived from a P-wave refraction database with over 13, 000 profiles, and a preliminary geology-based velocity model was constructed from available information on S-wave velocities. An interesting feature of the preliminary hazard maps incorporating site effects is the approximate factor of two increases in the 1-Hz spectral acceleration with 2 percent probability of exceedance in 50 years for parts of the greater Indianapolis metropolitan region and surrounding parts of central Indiana. This effect is primarily due to the relatively thick sequence of sediments infilling ancient bedrock topography that has been deposited since the Pleistocene Epoch. As expected, the Late Pleistocene and Holocene depositional systems of the Wabash and Ohio Rivers produce additional amplification in the southwestern part of Indiana. Ground motions decrease, as would be expected, toward the bedrock units in south-central Indiana, where motions are significantly lower than the values on the USGS maps.

  2. A study of local site effects in Benevento(Southern Italy by the analysis of seismic records of explosions

    Directory of Open Access Journals (Sweden)

    L. Mirabile

    1995-06-01

    Full Text Available In this paper we evalllate the seismic amplification effects in the town of Benevento llsing records of an explo- sion of 500 kg fired at abollt 7 km. Seismic records were obtained at 43 selected sites in the city by digital three-component stations. A data selection performed on the signal-to-noise ratio reduced the available data to 26 stations. We used the spectral ratio techniques to evaluate the amplification effects of each recording site compared both to the average spectrum calculated over 26 stations and to a reference seismic station. The shapes of the spectral ratios were classified according to the geological characteristics of the site. A characteristic shape of the spectral ratio was observed to be related to the specific structure of the subsoil. In particular, the sites on basin sediments (Lagonegro Unit and Middle Pleistocene conglomerates failed to show amplification effects; the sites on thick alluvial deposits showed amplification in the 5-9 Hz range; finally, sites on alluvial-lacustrine deposits amplified the seismic signal at frequencies depending on the characteristics and the thickness of the deposit. In addition, damage distribution caused by the 1688 earthquake in Benevento was related to the thickness of the surface layers in the ancient built-up area of the town. The study of the spectral ra- tios showed that these deposits amplify ground motion at frequencies between 9 and 12 Hz, i.e. frequencies close to the natural period of the most widespread buildings at that time in Benevento. Geological and seismic data were jointly used to carry out a zonation of the urban area of Benevento on the basis of homogeneous seismic responses. The validity of this analysis is limited to the main frequency band and amplitude of ground motion produced by the explosions.

  3. FSI effects and seismic performance evaluation of water storage tank of AP1000 subjected to earthquake loading

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chunfeng, E-mail: zhaowindy@126.com [Institute of Earthquake Engineering, Dalian University of Technology, Dalian 116024 (China); School of Civil Engineering, Hefei University of Technology, Anhui Province 230009 (China); Chen, Jianyun; Xu, Qiang [Institute of Earthquake Engineering, Dalian University of Technology, Dalian 116024 (China)

    2014-12-15

    Graphical abstract: - Highlights: • Water sloshing and oscillation of water tank under earthquake are simulated by FEM. • The influences of various water levels on seismic response are investigated. • ALE algorithm is applied to study the fluid–structure interaction effects. • The effects of different water levels in reducing seismic response are compared. • The optimal water level of water tank under seismic loading is obtained. - Abstract: The gravity water storage tank of AP1000 is designed to cool down the temperature of containment vessel by spray water when accident releases mass energy. However, the influence of fluid–structure interaction between water and water tank of AP1000 on dynamic behavior of shield building is still a hot research question. The main objective of the current study is to investigate how the fluid–structure interaction affects the dynamic behavior of water tank and whether the water sloshing and oscillation can reduce the seismic response of the shield building subjected to earthquake. For this purpose, a fluid–structure interaction algorithm of finite element technique is employed for the seismic analysis of water storage tank of AP1000. In the finite element model, 8 cases height of water, such as 10.8, 9.8, 8.8, 7.8, 6.8, 5.8, 4.8, and 3.8 m, are established and compared with the empty water tank in order to demonstrate the positive effect in mitigating the seismic response. An Arbitrary Lagrangian Eulerian (ALE) algorithm is used to simulate the fluid–structure interaction, fluid sloshing and oscillation of water tank under the El-Centro earthquake. The correlation between seismic response and parameters of water tank in terms of height of air (h{sub 1}), height of water (h{sub 2}), height ratio of water to tank (h{sub 2}/H{sub w}) and mass ratio of water to total structure (m{sub w}/m{sub t}) is also analyzed. The numerical results clearly show that the optimal h{sub 2}, h{sub 2}/H{sub w} and m{sub w}/m{sub t

  4. Effects of seismic intensity and socioeconomic status on injury and displacement after the 2007 Peru earthquake.

    Science.gov (United States)

    Milch, Karen; Gorokhovich, Yuri; Doocy, Shannon

    2010-10-01

    Earthquakes are a major cause of displacement, particularly in developing countries. Models of injury and displacement can be applied to assist governments and aid organisations in effectively targeting preparedness and relief efforts. A stratified cluster survey was conducted in January 2008 to evaluate risk factors for injury and displacement following the 15 August 2007 earthquake in southern Peru. In statistical modelling, seismic intensity, distance to rupture, living conditions, and educational attainment collectively explained 54.9 per cent of the variability in displacement rates across clusters. Living conditions was a particularly significant predictor of injury and displacement, indicating a strong relationship between risk and socioeconomic status. Contrary to expectations, urban, periurban, and rural clusters did not exhibit significantly different injury and displacement rates. Proxies of socioeconomic status, particularly the living conditions index score, proved relevant in explaining displacement, likely due to unmeasured aspects of housing construction practices and building materials. © 2010 The Author(s). Journal compilation © Overseas Development Institute, 2010.

  5. Co-Seismic Mass Dislocation and its Effect on Earth's Rotation and Gravity

    Science.gov (United States)

    Chao, B. F.; Gross, R. S.

    2002-01-01

    Mantle processes often involve large-scale mass transport, ranging from mantle convection, tectonic motions, glacial isostatic adjustment, to tides, atmospheric and oceanic loadings, volcanism and seismicity. On very short time scale of less than an hour, co-seismic event, apart from the shaking that is the earthquake, leaves behind permanent (step-function-like) dislocations in the crust and mantle. This redistribution of mass changes the Earth's inertia tensor (and hence Earth's rotation in both length-of-day and polar motion), and the gravity field (in terms of spherical harmonic Stokes coefficients). The question is whether these effects are large enough to be of any significance. In this paper we report updated calculation results based on Chao & Gross (1987). The calculation uses the normal mode summation scheme, applied to nearly twenty thousand major earthquakes that occurred during 1976-2002, according to source mechanism solutions given by the Harvard Central Moment Tensor catalog. Compared to the truly large ones earlier in the century, the earthquakes we study are individually all too small to have left any discernible signature in geodetic records of Earth rotation or global gravity field. However, their collective effects continue to exhibit an extremely strong statistical tendencies. For example, earthquakes conspire to decrease J2 and J22 while shortening LOD, resulting in a rounder and more compact Earth. Strong tendency is also seen in the earthquakes trying to nudge the Earth rotation pole towards approximately 140 degrees E, roughly opposite to the observed polar drift direction. The geophysical significance and implications will be further studied.

  6. Co-Seismic Mass Displacement and its Effect on Earth's Rotation and Gravity

    Science.gov (United States)

    Chao, B. F.; Gross, R. S.

    2004-01-01

    Mantle processes often involve large-scale mass transport, ranging from mantle convection, tectonic motions, glacial isostatic adjustment, to tides, atmospheric and oceanic loadings, volcanism and seismicity. On very short time scale of less than an hour, co-seismic event, apart from the "shaking" that is the earthquake, leaves behind permanent (step-function-like) displacements in the crust and mantle. This redistribution of mass changes the Earth's inertia tensor (and hence Earth's rotation in both length-of-day and polar motion), and the gravity field. The question is whether these effects are large enough to be of any significance. In this paper we report updated calculation results based on Chao & Gross. The calculation uses the normal mode summation scheme, applied to over twenty thousand major earthquakes that occurred during 1976-2002, according to source mechanism solutions given by the Harvard Centroid Moment Tensor catalog. Compared to the truly large ones earlier in the century, the earthquakes we study are individually all too small to have left any discernible signature in geodetic records of Earth rotation or global gravity field. However, their collective effects continue to exhibit an extremely strong statistical tendencies, conspiring to decrease J2 and J22 while shortening LOD, resulting in a rounder and more compact Earth. Strong tendency is also seen in the earthquakes trying to "nudge" the Earth rotation pole towards approx. 140 deg.E, roughly opposite to the observed polar drift direction. Currently, the Gravity Recovery And Climate Experiment (GRACE) is measuring the time-variable gravity to high degree and order with unprecedented accuracy. Our results show that great earthquakes such as the 1960 Chilean or 1964 Alaskan events cause gravitational field changes that are large enough to be detected by GRACE.

  7. Analysis of the Seismic Site Effects along the Ancient Via Laurentina (Rome

    Directory of Open Access Journals (Sweden)

    Francesca Bozzano

    2017-07-01

    Full Text Available This paper presents an evaluation of the Local Seismic Response (LSR along the route of the ancient Roman road Via Laurentina, which has been exposed in several areas of southwest Rome over the last decade during the construction of new buildings and infrastructures. It is an example of LSR analysis applied to ancient and archaeological sites located in alluvial valleys with some methodological inferences for the design of infrastructure and urban planning. Since the ancient road does not cross the alluvial valley (namely the Fosso di Vallerano Valley normal to its sides, it was not possible to directly perform 2D numerical modelling to evaluate the LSR along the road route. Therefore, outputs of 2D numerical models obtained along three cross sections that were normal oriented respect to the valley were projected along the route of the Via Laurentina within a reliable buffer attributed according to an available high-resolution geological model of the local subsoil. The modelled amplification functions consider physical effects due to both the 2D shape of the valley and the heterogeneities of the alluvial deposits. The 1D and 2D amplification functions were compared to output that non-negligible effects are related to the narrow shape of the fluvial valley and the lateral contacts between the lithotecnical units composing the alluvial fill. The here experienced methodology is suitable for applications to the numerical modelling of seismic response in case of linear infrastructures (i.e., roads, bridges, railways that do not cross the natural system along physically characteristic directions (i.e. longitudinally or transversally.

  8. Effect of the foundation stiffness on the response of a seismically isolated tank under SSE conditions

    NARCIS (Netherlands)

    Esposito, G.; Courage, W.

    2003-01-01

    This paper presents the results of a feasibility study of a seismic isolated 120.000 m3 LNG tank. A simple model was used to evaluate the seismic response of the isolated tank under Safe Shutdown Earthquake conditions. The frequency dependent dynamic stiffness of the foundation was

  9. Effect of dewatering on seismic performance of multi-anchor wall due to high ground water level

    Science.gov (United States)

    Kobayashi, Makoto; Miura, Kinya; Konami, Takeharu; Hayashi, Taketo; Sato, Hiroki

    2017-10-01

    Previous research reported that the ground water in the backfill of reinforced soil wall made it deteriorate. According to the damage investigation of Great East Earthquake 2011, the reinforced soil structure due to high ground water level by seismic wave were deformed remarkably. Some of them classified ultimate limit state or restorability limit state. However, more than 90% of reinforced soil structure, which suffered from this earthquake, were classified into no damage condition. Therefore, it is necessary that the seismic behaviors of multi-anchor wall due to seepage flow should be clarified in order to adopt the performance-based design in such reinforced soil structure. In this study, a series of centrifugal shaking table tests were conducted to investigate the seismic behavior of multi-anchor wall due to high ground water level. The reinforced drainage pipes were installed into the backfill in order to verify the dewatering effect and additional reinforcement. Furthermore, to check only the dewatering effect, the model tests was carried out with several ground water table that was modeled the case reinforced drainage pipes installed. The test results show unique behavior of reinforced region that moved integrally. This implies that the reinforced region has been behaved as if it became one mass, and this behavior make this structure increase seismic performance. Thus, the effectiveness of dewatering was observed remarkably because of decreasing the inertial force during earthquake.

  10. Effectiveness of ANN for seismic behaviour prediction considering geometric configuration effect in concrete gravity dams

    Directory of Open Access Journals (Sweden)

    Mohd. Saqib

    2016-09-01

    Full Text Available In this study, an Artificial Neural Networks (ANN model is built and verified for quick estimation of the structural parameter obtained for a concrete gravity dam section due to seismic excitation. The database of numerous inputs and outputs obtained through Abaqus which are further converted into dimensionless forms in the statistical software (MATLAB to build the ANN model. The developed model can be used for accurate estimation of this parameter. The results showed an excellent capability of the model to predict the outputs with high accuracy and reduced computational time.

  11. Discrimination between pre-seismic electromagnetic anomalies and solar activity effects

    Science.gov (United States)

    Koulouras, G.; Balasis, G.; Kiourktsidis, I.; Nannos, E.; Kontakos, K.; Stonham, J.; Ruzhin, Y.; Eftaxias, K.; Cavouras, D.; Nomicos, C.

    2009-04-01

    Laboratory studies suggest that electromagnetic emissions in a wide frequency spectrum ranging from kilohertz (kHz) to very high megahertz (MHz) frequencies are produced by the opening of microcracks, with the MHz radiation appearing earlier than the kHz radiation. Earthquakes are large-scale fracture phenomena in the Earth's heterogeneous crust. Thus, the radiated kHz-MHz electromagnetic emissions are detectable not only in the laboratory but also at a geological scale. Clear MHz-to-kHz electromagnetic anomalies have been systematically detected over periods ranging from a few days to a few hours prior to recent destructive earthquakes in Greece. We should bear in mind that whether electromagnetic precursors to earthquakes exist is an important question not only for earthquake prediction but mainly for understanding the physical processes of earthquake generation. An open question in this field of research is the classification of a detected electromagnetic anomaly as a pre-seismic signal associated with earthquake occurrence. Indeed, electromagnetic fluctuations in the frequency range of MHz are known to be related to a few sources, including atmospheric noise (due to lightning), man-made composite noise, solar-terrestrial noise (resulting from the Sun-solar wind-magnetosphere-ionosphere-Earth's surface chain) or cosmic noise, and finally, the lithospheric effect, namely pre-seismic activity. We focus on this point in this paper. We suggest that if a combination of detected kHz and MHz electromagnetic anomalies satisfies the set of criteria presented herein, these anomalies could be considered as candidate precursory phenomena of an impending earthquake.

  12. Discrimination between pre-seismic electromagnetic anomalies and solar activity effects

    International Nuclear Information System (INIS)

    Koulouras, G; Kiourktsidis, I; Stonham, J; Balasis, G; Nannos, E; Kontakos, K; Nomicos, C; Ruzhin, Y; Eftaxias, K; Cavouras, D

    2009-01-01

    Laboratory studies suggest that electromagnetic emissions in a wide frequency spectrum ranging from kilohertz (kHz) to very high megahertz (MHz) frequencies are produced by the opening of microcracks, with the MHz radiation appearing earlier than the kHz radiation. Earthquakes are large-scale fracture phenomena in the Earth's heterogeneous crust. Thus, the radiated kHz-MHz electromagnetic emissions are detectable not only in the laboratory but also at a geological scale. Clear MHz-to-kHz electromagnetic anomalies have been systematically detected over periods ranging from a few days to a few hours prior to recent destructive earthquakes in Greece. We should bear in mind that whether electromagnetic precursors to earthquakes exist is an important question not only for earthquake prediction but mainly for understanding the physical processes of earthquake generation. An open question in this field of research is the classification of a detected electromagnetic anomaly as a pre-seismic signal associated with earthquake occurrence. Indeed, electromagnetic fluctuations in the frequency range of MHz are known to be related to a few sources, including atmospheric noise (due to lightning), man-made composite noise, solar-terrestrial noise (resulting from the Sun-solar wind-magnetosphere-ionosphere-Earth's surface chain) or cosmic noise, and finally, the lithospheric effect, namely pre-seismic activity. We focus on this point in this paper. We suggest that if a combination of detected kHz and MHz electromagnetic anomalies satisfies the set of criteria presented herein, these anomalies could be considered as candidate precursory phenomena of an impending earthquake.

  13. Seismic Ecology

    Science.gov (United States)

    Seleznev, V. S.; Soloviev, V. M.; Emanov, A. F.

    The paper is devoted to researches of influence of seismic actions for industrial and civil buildings and people. The seismic actions bring influence directly on the people (vibration actions, force shocks at earthquakes) or indirectly through various build- ings and the constructions and can be strong (be felt by people) and weak (be fixed by sensing devices). The great number of work is devoted to influence of violent seismic actions (first of all of earthquakes) on people and various constructions. This work is devoted to study weak, but long seismic actions on various buildings and people. There is a need to take into account seismic oscillations, acting on the territory, at construction of various buildings on urbanized territories. Essential influence, except for violent earthquakes, man-caused seismic actions: the explosions, seismic noise, emitted by plant facilities and moving transport, radiation from high-rise buildings and constructions under action of a wind, etc. can exert. Materials on increase of man- caused seismicity in a number of regions in Russia, which earlier were not seismic, are presented in the paper. Along with maps of seismic microzoning maps to be built indicating a variation of amplitude spectra of seismic noise within day, months, years. The presence of an information about amplitudes and frequencies of oscillations from possible earthquakes and man-caused oscillations in concrete regions allows carry- ing out soundly designing and construction of industrial and civil housing projects. The construction of buildings even in not seismically dangerous regions, which have one from resonance frequencies coincident on magnitude to frequency of oscillations, emitted in this place by man-caused objects, can end in failure of these buildings and heaviest consequences for the people. The practical examples of detail of engineering- seismological investigation of large industrial and civil housing projects of Siberia territory (hydro power

  14. An effective absorbing layer for the boundary condition in acoustic seismic wave simulation

    Science.gov (United States)

    Yao, Gang; da Silva, Nuno V.; Wu, Di

    2018-04-01

    Efficient numerical simulation of seismic wavefields generally involves truncating the Earth model in order to keep computing time and memory requirements down. Absorbing boundary conditions, therefore, are applied to remove the boundary reflections caused by this truncation, thereby allowing for accurate modeling of wavefields. In this paper, we derive an effective absorbing boundary condition for both acoustic and elastic wave simulation, through the simplification of the damping term of the split perfectly matched layer (SPML) boundary condition. This new boundary condition is accurate, cost-effective, and easily implemented, especially for high-performance computing. Stability analysis shows that this boundary condition is effectively as stable as normal (non-absorbing) wave equations for explicit time-stepping finite differences. We found that for full-waveform inversion (FWI), the strengths of the effective absorbing layer—a reduction of the computational and memory cost coupled with a simplistic implementation—significantly outweighs the limitation of incomplete absorption of outgoing waves relative to the SPML. More importantly, we demonstrate that this limitation can easily be overcome through the use of two strategies in FWI, namely variable cell size and model extension thereby fully compensating for the imperfectness of the proposed absorbing boundary condition.

  15. Comparison of seismic isolation concepts for FBR

    International Nuclear Information System (INIS)

    Shiojiri, H.; Mazda, T.; Kasai, H.; Kanda, J.N.; Kubo, T.; Madokoro, M.; Shimomura, T.; Nojima, O.

    1989-01-01

    This paper seeks to verify the reliability and effectiveness of seismic isolation for FBR. Some results of the preliminary study of the program are described. Seismic isolation concepts and corresponding seismic isolation devices were selected. Three kinds of seismically-isolated FBR plant concepts were developed by applying promising seismic isolation concepts to the non-isolated FBR plant, and by developing plant component layout plans and building structural designs. Each plant was subjected to seismic response analysis and reduction in the amount of material of components and buildings were estimated for each seismic isolation concepts. Research and development items were evaluated

  16. Development of seismic analysis method considered FSI effect on a neutron reflector for APWR reactor internals

    Energy Technology Data Exchange (ETDEWEB)

    Hideyuki, Morika; Tomomichi, Nakamura [Mitsubishi Heavy Industries Ltd., Takasago R and D Center, Hyogo (Japan); Toshio, Ichikawa; Kazuo, Hirota; Hiroyuki, Murakiso [Mitsubishi Heavy Industries Ltd., Kobe Shipyard and Machinery Works, Hyogo, Kobe (Japan); Minoru, Murota [Japan Atomic Power Co., Tokyo (Japan)

    2004-07-01

    A Neutron Reflector (NR) is a new structure designed for improving the structure reliability of Advanced Pressurized Water Reactors (APWR,). The NR is placed in a narrow gap between the NR and a Core Barrel (CB). In the case of a structure surrounded by liquid in a narrow gap, the added fluid mass and the damping increases compared with in the air. This effect is famous for Fluid-Structure Interaction effect (FSI effect) in the narrow gap and it depends on the vibration displacement of the structure. A new method to estimate the added fluid damping for this case has been introduced by some of the authors in 2001, which is based on a narrow passage flow theory (Morita et al., 2001). Following this theory, a vibration test was performed to assess the appropriateness of the analysis method employed to measure the response of the NR during an earthquake (Nakamura et al., 2002). In this paper, results of a model test are shown comparing the data with the calculated ones based on the new analysis method that is combined the above method with the ANSYS computer code. As a result, a new seismic analysis method using the above theory was developed. The analytical results are in good agreement with the test results. (authors)

  17. Hovsgol earthquake 5 December 2014, M W = 4.9: seismic and acoustic effects

    Science.gov (United States)

    Dobrynina, Anna A.; Sankov, Vladimir A.; Tcydypova, Larisa R.; German, Victor I.; Chechelnitsky, Vladimir V.; Ulzibat, Munkhuu

    2018-03-01

    A moderate shallow earthquake occurred on 5 December 2014 ( M W = 4.9) in the north of Lake Hovsgol (northern Mongolia). The infrasonic signal with duration 140 s was recorded for this earthquake by the "Tory" infrasound array (Institute of Solar-Terrestrial Physics of the Siberian Branch of the Russian Academy of Science, Russia). Source parameters of the earthquake (seismic moment, geometrical sizes, displacement amplitudes in the focus) were determined using spectral analysis of direct body P and S waves. The spectral analysis of seismograms and amplitude variations of the surface waves allows to determine the effect of the propagation of the rupture in the earthquake focus, the azimuth of the rupture propagation direction and the velocity of displacement in the earthquake focus. The results of modelling of the surface displacements caused by the Hovsgol earthquake and high effective velocity of propagation of infrasound signal ( 625 m/s) indicate that its occurrence is not caused by the downward movement of the Earth's surface in the epicentral region but by the effect of the secondary source. The position of the secondary source of infrasound signal is defined on the northern slopes of the Khamar-Daban ridge according to the data on the azimuth and time of arrival of acoustic wave at the Tory station. The interaction of surface waves with the regional topography is proposed as the most probable mechanism of formation of the infrasound signal.

  18. Effects of Permafrost and Seasonally Frozen Ground on the Seismic Response of Transportation Infrastructure Sites

    Science.gov (United States)

    2010-02-01

    This interdisciplinary project combined seismic data recorded at bridge sites with computer models to identify how highway bridges built on permanently and seasonally frozen ground behave during an earthquake. Two sites one in Anchorage and one in...

  19. Laboratory piping system vibration tests to determine parametric effects on damping in the seismic frequency range

    International Nuclear Information System (INIS)

    Ware, A.G.

    1987-01-01

    A pipe damping research program is being conducted for the United States Nuclear Regulatory Commission at the Idaho National Engineering Laboratory to establish more realistic, best-estimate damping values for use in dynamic structural analyses of piping systems. As part of this program, tests were conducted on a 5-in. (128 mm ID) laboratory piping system to determine the effects of pressure, support configuration, insulation and response amplitude on damping. The tests were designed to produce a wide range of damping values, from very low damping in lightly excited uninsulated systems with few supports, to higher damping under conditions of either/or insulation, high level excitation, and various support arrangements. The effect of pressure at representative seismic levels was considered to be minimal. The supports influence damping at all excitation levels; damping was highest when a mechanical snubber was present in the system. The addition of insulation produced a large increase in damping for the hydraulic shaker excitation tests, but there was no comparable increase for the snapback excitation tests. Once a response amplitude of approximately one-half yield stress was reached, overall damping increased to relatively high levels (>10% of critical)

  20. Potential Settlement Due to Seismic Effects in the Residential Area of Ilgin (Konya, Turkey

    Directory of Open Access Journals (Sweden)

    Adnan Ozdemir

    2016-04-01

    Full Text Available Ilgin lies on newly formed, loose, granular deposits, and there is a substantial risk for surface liquefaction and foundation settlements due to the seismic effects resulting from groundwater close to the surface. This study evaluates potential settlement due to seismic effects in the residential areas of Ilgin using the Standard Penetration Test (SPT performed on 45 geotechnical bores. In Turkey, where earthquakes occur frequently, the selection of residential areas is of great importance. In this research, the number of settlements was calculated considering an earthquake having a Local Magnitude of 6 (i.e., ML ≥ 6.0 and a ≥ 0.4 g under a 0.4 g seismic force, and a potential settlement map of the residential area was prepared. The amount of settlement exceeds 20 cm at locations near Ilgin Lake and in the northern section of Ilgin residential areas; downtown, the settlement ranges from 10-20 cm. The settlements presented here exceed the allowable threshold limits for structures constructed using adobe and brick in this district. Thus, improvements to minimize earthquake-induced damages are required for structures in Ilgin. Moreover, the selection of new residential areas, along with the proper design of the structures before construction, should be examined further to avoid ground liquefaction and structure damage due to settlement.    Resumen La localidad de Ilgin está ubicada sobre depósitos recién formados, granulares y no compactos, por lo que existe un riesgo sustancial de licuefacción de la superficie y la creación de asentamientos o deslizamientos debido a los efectos sísmicos resultantes del agua subterránea poco profunda. Este artículo evalúa el potencial de asentamiento debido a los efectos sísmicos en las áreas residenciales de Ilgin a través del Ensayo de Penetración Estándar (SPT, en inglés realizado en 45 perforaciones geotécnicas. En Turquía, donde los terremotos ocurren frecuentemente, la selección de

  1. Three dimensional marine seismic survey has no measurable effect on species richness or abundance of a coral reef associated fish community

    International Nuclear Information System (INIS)

    Miller, Ian; Cripps, Edward

    2013-01-01

    Highlights: • A marine seismic survey was conducted at Scott Reef, North Western Australia. • Effects of the survey on demersal fish were gauged using underwater visual census. • There was no detectable impact of the seismic survey on species abundance. • There was no detectable impact of the seismic survey on species richness. -- Abstract: Underwater visual census was used to determine the effect of a three dimensional seismic survey on the shallow water coral reef slope associated fish community at Scott Reef. A census of the fish community was conducted on six locations at Scott Reef both before and after the survey. The census included small site attached demersal species belonging to the family Pomacentridae and larger roving demersal species belonging to the non-Pomacentridae families. These data were combined with a decade of historical data to assess the impact of the seismic survey. Taking into account spatial, temporal, spatio-temporal and observer variability, modelling showed no significant effect of the seismic survey on the overall abundance or species richness of Pomacentridae or non-Pomacentridae. The six most abundant species were also analysed individually. In all cases no detectable effect of the seismic survey was found on the abundance of these fish species at Scott Reef

  2. Seismic pressure effect on retaining walls; Presiones generadas por sismo en muros de retencion

    Energy Technology Data Exchange (ETDEWEB)

    Bonola, Isaac; Aviles, Javier [Instituto Mexicano de Tecnologia del Agua, Jiutepec, Morelos (Mexico)

    2006-04-15

    Retaining walls are auxiliary works used in different hydraulic structures. In seismically active areas, the dynamic pressures generated by the backfill must be appropriately evaluated at the design stage. Currently, a number of methods for estimating the seismic response of this type of works are available; however, most of them are simplified and not all the parameters involved have been examined. In this paper, a hybrid boundary and finite element method is presented for gravity walls in which the backfill can be represented by a horizontally layered medium. The effect of lateral extension of the backfill can be included in the model by introducing a vertical boundary coupling the movement of the backfill with that of the surrounding soil. The wave propagation analysis in the layered medium is carried out for both horizontal and vertical harmonic excitation; the latter excitation may cause important responses under certain situations. To illustrate the applicability of the proposed method, results for two numerical examples are presented: one for dry backfill and other for saturated backfill, considering in both cases the variations of dynamic properties of the soil with the depth. [Spanish] Los muros de retencion son estructuras auxiliares utilizadas en distintas obras hidraulicas. En zonas sismicas, las presiones dinamicas generadas por el relleno deben evaluarse adecuadamente en la etapa de diseno. Actualmente existen numerosos metodos para estimar la respuesta sismica de este tipo de estructuras; sin embargo, la mayoria de ellos son simplificados y no todos los parametros involucrados han sido examinados. En este trabajo se presenta un metodo hibrido de frontera y elemento finito para muros de gravedad en el que el relleno puede representarse por un medio estratificado horizontalmente. En el modelo puede incluirse el efecto de la extension lateral del relleno, introduciendo una frontera vertical que acopla el movimiento del relleno con el del suelo

  3. Seismic Site Effects from the Seafloor Motion Recorded by the Short-period Ocean Bottom Seismometers

    Science.gov (United States)

    Lin, J. Y.; Cheng, W. B.; Chin, S. J.; Hsu, S. K.; Dong, J. J.

    2014-12-01

    For decades, it has been mentioned that submarine slope failures are spatially linked to the presence of gas hydrates/gas-charged sediments. When triggered by earthquakes, oversteepen and instable sediments may prompt breakouts of the slopes containing gas hydrates and cause submarine landslides and tsunamis. Widely distributed BSRs have been observed in the area offshore of southwestern Taiwan where the active accretionary complex meets with the passive China continental margin. In the region, large or small scale landslides were also reported based on seismic interpretations. In order to clarify the link between earthquake, landslide and the presence of gas hydrate, we evaluate the response of seafloor sediments in regard to passive dynamic loads. Horizontal-to-vertical (H/V) spectral ratios are used to characterize the local sediment response. Ambient noise as well as distant earthquakes are used as generators of the passive dynamic loads. Based on this study, we aim to characterize the site in terms of its physical properties and the local site effect produced by shallow marine sediments. The results show that the maximum H/V ratios appeared in the range of 5-10 Hz, where the horizontal amplitudes increased by an order of magnitude relative to the vertical amplitude. The stations located in the northwestern part of study area were characterized by another relatively small peak at proximately 2 Hz, which may indicates the presence of a discontinuity of sediments. For most stations, the H/V ratios estimated based on the earthquake (i.e. strong input signal) and noise (background, micro-seismic noise) records were characterized by different pattern. No distinct peak is observed for the H/V pattern calculated during earthquakes. This phenomenon may suggest that no clear sedimentary boundary exist when a stronger motion applies. Estimating H/V spectral ratios of data recorded by the seven short period OBSs (Ocean Bottom Seismometer) deployed in the southwest Taiwan

  4. Investigating effects of near fault rupture directivity on seismic hazard assessment of the site of Tehran Research Reactor (TRR)

    Energy Technology Data Exchange (ETDEWEB)

    Sepanloo, Kamran; Saberi, Reza [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Alinejad, Majid [Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of); Bazarchi, Ehsan [Tabriz Univ. (Iran, Islamic Republic of)

    2017-10-15

    It is estimated that the occurrence of a major-earthquake in Tehran, Iran, which is not far-fetched, would face the country with a huge amount of collapsed structures, economical losses and fatalities. The issue becomes more important while the site of interest is attributed to the nuclear facilities and any under-estimation in predicting the design ground motion may cause a real disaster. In this study, using calculations coded in MATLAB, PSHA was conducted for the site of TRR. It was concluded that most of the hazard for considered site in a 10000-year period comes from distances lower than 20 km and considering rupture directivity effects of the North Tehran fault, as the nearest seismicity source to considered site, using narrowband method affected the response spectrum significantly. Therefore, it is necessary to incorporate the near fault rupture directivity effects into the higher levels of seismic hazard assessment attributed to important sites.

  5. Investigating effects of near fault rupture directivity on seismic hazard assessment of the site of Tehran Research Reactor (TRR)

    International Nuclear Information System (INIS)

    Sepanloo, Kamran; Saberi, Reza; Alinejad, Majid; Bazarchi, Ehsan

    2017-01-01

    It is estimated that the occurrence of a major-earthquake in Tehran, Iran, which is not far-fetched, would face the country with a huge amount of collapsed structures, economical losses and fatalities. The issue becomes more important while the site of interest is attributed to the nuclear facilities and any under-estimation in predicting the design ground motion may cause a real disaster. In this study, using calculations coded in MATLAB, PSHA was conducted for the site of TRR. It was concluded that most of the hazard for considered site in a 10000-year period comes from distances lower than 20 km and considering rupture directivity effects of the North Tehran fault, as the nearest seismicity source to considered site, using narrowband method affected the response spectrum significantly. Therefore, it is necessary to incorporate the near fault rupture directivity effects into the higher levels of seismic hazard assessment attributed to important sites.

  6. Burar seismic station: evaluation of seismic performance

    International Nuclear Information System (INIS)

    Ghica, Daniela; Popa, Mihaela

    2005-01-01

    of the arrival times picking and phase characterization. The data collected and recorded by the BURAR monitoring seismic station are an important source of information regarding local seismicity (mainly in the northern and western part of the Romanian territory). Source or path effects are better detected as well. (authors)

  7. Masonry Infilling Effect On Seismic Vulnerability and Performance Level of High Ductility RC Frames

    International Nuclear Information System (INIS)

    Ghalehnovi, M.; Shahraki, H.

    2008-01-01

    In last years researchers preferred behavior-based design of structure to force-based one for designing and construction of the earthquake-resistance structures, this method is named performance based designing. The main goal of this method is designing of structure members for a certain performance or behavior. On the other hand in most of buildings, load bearing frames are infilled with masonry materials which leads to considerable changes in mechanical properties of frames. But usually infilling wall's effect has been ignored in nonlinear analysis of structures because of complication of the problem and lack of simple logical solution. As a result lateral stiffness, strength, ductility and performance of the structure will be computed with less accuracy. In this paper by use of Smooth hysteretic model for masonry infillings, some high ductile RC frames (4, 8 stories including 1, 2 and 3 spans) designed according to Iranian code are considered. They have been analyzed by nonlinear dynamic method in two states, with and without infilling. Then their performance has been determined with criteria of ATC 40 and compared with recommended performance in Iranian seismic code (standard No. 2800)

  8. Effects of embedment including slip and separation on seismic SSI response of a nuclear reactor building

    International Nuclear Information System (INIS)

    Saxena, Navjeev; Paul, D.K.

    2012-01-01

    Highlights: ► Both the slip and separation of reactor base reduce with increase in embedment. ► The slip and separation become insignificant beyond 1/4 and 1/2 embedment respectively. ► The stresses in reactor reduce significantly upto 1/4 embedment. ► The stress reduction with embedment is more pronounced in case of tensile stresses. ► The modeling of interface is important beyond 1/8 embedment as stresses are underestimated otherwise. - Abstract: The seismic response of nuclear reactor containment building considering the effects of embedment, slip and separation at soil–structure interface requires modeling of the soil, structure and interface altogether. Slip and separation at the interface causes stress redistribution in the soil and the structure around the interface. The embedment changes the dynamic characteristics of the soil–structure system. Consideration of these aspects allows capturing the realistic response of the structure, which has been a research gap and presented here individually as well as taken together. Finite element analysis has been carried out in time domain to attempt the highly nonlinear problem. The study draws important conclusions useful for design of nuclear reactor containment building.

  9. Effects of Exposure to the Sound from Seismic Airguns on Pallid Sturgeon and Paddlefish.

    Directory of Open Access Journals (Sweden)

    Arthur N Popper

    Full Text Available This study examined the effects of exposure to a single acoustic pulse from a seismic airgun array on caged endangered pallid sturgeon (Scaphirhynchus albus and on paddlefish (Polyodon spathula in Lake Sakakawea (North Dakota, USA. The experiment was designed to detect the onset of physiological responses including minor to mortal injuries. Experimental fish were held in cages as close as 1 to 3 m from the guns where peak negative sound pressure levels (Peak- SPL reached 231 dB re 1 μPa (205 dB re 1 μPa2·s sound exposure level [SEL]. Additional cages were placed at greater distances in an attempt to develop a dose-response relationship. Treatment and control fish were then monitored for seven days, euthanized, and necropsied to determine injuries. Necropsy results indicated that the probability of delayed mortality associated with pulse pressure following the seven day monitoring period was the same for exposed and control fish of both species. Exposure to a single pulse from a small air gun array (10,160 cm3 was not lethal for pallid sturgeon and paddlefish. However, the risks from exposure to multiple sounds and to sound exposure levels that exceed those reported here remain to be examined.

  10. Effects of the symmetry axis orientation of a TI overburden on seismic images

    Science.gov (United States)

    Chang, Chih-Hsiung; Chang, Young-Fo; Tseng, Cheng-Wei

    2017-07-01

    In active tectonic regions, the primary formations are often tilted and subjected to the processes of folding and/or faulting. Dipping formations may be categorised as tilted transverse isotropy (TTI). While carrying out hydrocarbon exploration in areas of orogenic structures, mispositioning and defocusing effects in apparent reflections are often caused by the tilted transverse isotropy of the overburden. In this study, scaled physical modelling was carried out to demonstrate the behaviours of seismic wave propagation and imaging problems incurred by transverse isotropic (TI) overburdens that possess different orientations of the symmetry axis. To facilitate our objectives, zero-offset reflections were acquired from four stratum-fault models to image the same structures that were overlain by a TI (phenolite) slab. The symmetry axis of the TI slab was vertical, tilted or horizontal. In response to the symmetry axis orientations, spatial shifts and asymmetrical diffraction patterns in apparent reflections were observed in the acquired profiles. Given the different orientations of the symmetry axis, numerical manipulations showed that the imaged events could be well described by theoretical ray paths computed by the trial-and-error ray method and Fermat's principle (TERF) method. In addition, outputs of image restoration show that the imaging problems, i.e. spatial shift in the apparent reflections, can be properly handled by the ray-based anisotropic 2D Kirchhoff time migration (RAKTM) method.

  11. A new seismic station in Romania the Bucovina seismic array

    International Nuclear Information System (INIS)

    Grigore, Adrian; Grecu, Bogdan; Ionescu, Constantin; Ghica, Daniela; Popa, Mihaela; Rizescu, Mihaela

    2002-01-01

    Recently, a new seismic monitoring station, the Bucovina Seismic Array, has been established in the northern part of Romania, in a joint effort of the Air Force Technical Applications Center, USA, and the National Institute for Earth Physics, Romania. The array consists of 10 seismic sensors (9 short-period and one broad band) located in boreholes and distributed in a 5 x 5 km area. On July 24, 2002 the official Opening Ceremony of Bucovina Seismic Array took place in the area near the city of Campulung Moldovenesc in the presence of Romanian Prime Minister, Adrian Nastase. Starting with this date, the new seismic monitoring system became fully operational by continuous recording and transmitting data in real-time to the National Data Center of Romania, in Bucharest and to the National Data Center of USA, in Florida. Bucovina Seismic Array, added to the present Seismic Network, will provide much better seismic monitoring coverage of Romania's territory, on-scale recording for weak-to-strong events, and will contribute to advanced seismological studies on seismic hazard and risk, local effects and microzonation, seismic source physics, Earth structure. (authors)

  12. Study of Site Effect at Seismic Station Located in Undermined Area of Karviná Region (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Lednická, Markéta; Kaláb, Zdeněk

    2016-01-01

    Roč. 64, č. 5 (2016), s. 1715-1730 ISSN 1895-7455 R&D Projects: GA ČR GP13-07027P Institutional support: RVO:68145535 Keywords : Karviná region * site effect * SSR * HVSR * mining induced seismicity Subject RIV: JM - Building Engineering Impact factor: 0.968, year: 2016 http://agp.igf.edu.pl/files/64/5/Lednicka-Kalab.pdf

  13. Analysis of the effects of corrosion probe on riser 241-AN-102-WST-16 during seismic event

    International Nuclear Information System (INIS)

    ZIADA, H.H.

    1998-01-01

    This analysis supports the installation activity of the corrosion probe in Tank 241-AN-102. The probe is scheduled to be installed in Riser 241-AN-102-WST-16 (formerly known as Riser 15B). The purpose of this analysis is to evaluate the potential effect of the corrosion probe on the riser during a credible seismic event. The previous analysis (HNF 1997a) considered only pump jet impingement loading

  14. Seismic ground motion characteristics in the Bucharest area: source and site effects contribution

    International Nuclear Information System (INIS)

    Grecu, B.; Popa, M.; Radulian, M.

    2003-01-01

    The contribution of source vs. site effects on the seismic ground motion in Bucharest is controversial as the previous studies showed. The fundamental period of resonance for the sedimentary cover is emphasized by ambient noise and earthquake measurements, if the spectral ratio method (Nakamura, 1989) is applied (Bonjer et al., 1989). On the other hand, the numerical simulations (Moldoveanu et al., 2000.) and acceleration spectra analysis (Sandi et al., 2001) brought into the light the determinant role of the source effects. We considered all the available instrumental data related to Vrancea earthquakes recorded in Bucharest area to find how the source and site properties control the peak ground motion peculiarities. Our main results are summarized as follows: 1. The resonant period of oscillation, related to the shallow sediment layer, is practically present in all the H/V spectral ratios, no matter we consider ambient noise or earthquakes of any size. This argues in favor of the crucial role played by the sedimentary cover and proves that the ratio method is reasonably removing the source effects. However, the absolute spectra are completely different for earthquakes below and above magnitude 7, namely amplitudes in the range of 1-2 s periods are negligible in the first case, and predominant in the second one. It looks like the resonant amplification by the sedimentary cover becomes effective only for the largest earthquakes (M > 7), when the source radiation coincides with the fundamental resonance range. We conclude that the damage in Bucharest is dramatically amplified when the earthquake size is above a critical value (M ≅ 7); 2. Our analysis shows a rather weak variability of the peak motion values and spectral amplitudes over the study area, in agreement with the relatively small variability of the shallow structure topography. (authors)

  15. Task force activity to take the effect of elastic-plastic behaviour into account on the seismic safety evaluation of nuclear piping systems

    International Nuclear Information System (INIS)

    Nakamura, Izumi; Shiratori, Masaki; Morishita, Masaki; Otani, Akihito; Shibutani, Tadahito

    2015-01-01

    According to investigations of several nuclear power plants (NPPs) hit by actual seismic events and a number of experimental researches on the failure behavior of piping systems under seismic loads, it is recognized that piping systems used in NPPs include a large seismic safety margin until boundary failure. Since the stress assessment based on the elastic analysis does not reflect actual seismic capability of piping systems including plastic region, it is necessary to develop a rational procedures to estimate the elastic-plastic behavior of piping systems under a large seismic load. With the aim of establishing a procedure that takes into account the elastic-plastic behavior effect in the seismic safety estimation of nuclear piping systems, a task force activity has been planned. Through the activity, the authors intend to establish guidelines to estimate the elastic-plastic behavior of piping systems rationally and conservatively, and to provide new rational seismic safety criteria taking the effect of elastic-plastic behavior into account. As the first step of making out the analysis guideline, benchmark analyses are conducted for a pipe element test and a piping system test. In this paper, the outline of the research activity and the preliminary results of benchmark analyses are described. (author)

  16. 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.

  17. The effect of intra-trappean heterogeneities on seismic data: A case study from the Deccan Traps

    Science.gov (United States)

    Pandey, Dhananjai; Singh, Satish; Sinha, Martin; MacGregor, Lucy

    2007-09-01

    Hydrocarbon exploration interests have renewed the need for developing new sub basalt imaging techniques. One of the most important problems encountered today is seismic imaging below basalt. In recent years, this problem appears to have been overcome partly by using long offset seismic data. However near offset data are yet to be fully utilised due to the complex waveform caused by the surface as well as internal heterogeneity of the basalts. The near normal incidence data, which influence the sub-basalt imaging, are highly useful to understand the internal structure within a basalt layer. The use of converted waves for such targets has been proposed as an alternative in a rather homogeneous basalt layer. With a few synthetic modelling exercises here we highlight the practical difficulties in dealing with more realistic and heterogeneous basalt flow. Full waveform seismograms are computed to understand the effects of intra-trappean sediments on the seismic data. A case study from the Deccan Traps of India is presented in this paper. First, we discuss the effects of intercalated sediments on the overall seismic image. Later, the sonic log data from the field are used to compute the full wave-field response using the reflectivity method and compared with the field data. The feasibility of using mode converted waves (P to S and vice-versa at the top and bottom basalt interfaces) for sub-basalt imaging in Kutch region is discussed through a series of velocity-depth profiles. By comparing with the field data we demonstrate that the effects of multiple thin layering within the basalt can strongly deteriorate the image we seek to interpret and exploit.

  18. Effects of non-structural components and soil-structure interaction on the seismic response of framed structures

    Science.gov (United States)

    Ditommaso, Rocco; Auletta, Gianluca; Iacovino, Chiara; Nigro, Antonella; Carlo Ponzo, Felice

    2017-04-01

    In this paper, several nonlinear numerical models of reinforced concrete framed structures have been defined in order to evaluate the effects of non-structural elements and soil-structure interaction on the elastic dynamic behaviour of buildings. In the last few years, many and various studies have highlighted the significant effects derived from the interaction between structural and non-structural components on the main dynamic characteristics of a building. Usually, structural and non-structural elements act together, adding both masses and stiffness. The presence of infill panels is generally neglected in the design process of structural elements, although these elements can significantly increase the lateral stiffness of a structure leading to a modification in the dynamic properties. Particularly, at the Damage Limit State (where an elastic behaviour is expected), soil-structure interaction effects and non-structural elements may further affect the elastic natural period of buildings, changing the spectral accelerations compared with those provided by seismic codes in case of static analyses. In this work, a parametric study has been performed in order to evaluate the elastic fundamental period of vibration of buildings as a function of structural morphology (height, plan area, ratio between plan dimensions), infills presence and distribution and soil characteristics. Acknowledgements This study was partially funded by the Italian Department of Civil Protection within the project DPC-RELUIS 2016 - RS4 ''Seismic observatory of structures and health monitoring'' and by the "Centre of Integrated Geomorphology for the Mediterranean Area - CGIAM" within the Framework Agreement with the University of Basilicata "Study, Research and Experimentation in the Field of Analysis and Monitoring of Seismic Vulnerability of Strategic and Relevant Buildings for the purposes of Civil Protection and Development of Innovative Strategies of Seismic Reinforcement".

  19. Comparison of seismic sources for shallow seismic: sledgehammer and pyrotechnics

    Directory of Open Access Journals (Sweden)

    Brom Aleksander

    2015-10-01

    Full Text Available The pyrotechnic materials are one of the types of the explosives materials which produce thermal, luminous or sound effects, gas, smoke and their combination as a result of a self-sustaining chemical reaction. Therefore, pyrotechnics can be used as a seismic source that is designed to release accumulated energy in a form of seismic wave recorded by tremor sensors (geophones after its passage through the rock mass. The aim of this paper was to determine the utility of pyrotechnics for shallow seismic engineering. The work presented comparing the conventional method of seismic wave excitation for seismic refraction method like plate and hammer and activating of firecrackers on the surface. The energy released by various sources and frequency spectra was compared for the two types of sources. The obtained results did not determine which sources gave the better results but showed very interesting aspects of using pyrotechnics in seismic measurements for example the use of pyrotechnic materials in MASW.

  20. On the effectiveness of smart technologies in the seismic protection of existing buildings Part I: Masonry structures

    International Nuclear Information System (INIS)

    Mandara, A.; Ramundo, F.; Spina, G.

    2008-01-01

    The first part of a study concerning innovative intervention techniques for dissipate a share of the input seismic energy compatible with the preservation of existing buildings, including historical and monumental constructions, is presented in this paper. The case of a typical scheme of a long-bay box-like masonry building fitted with a dissipative floating roof is analyzed. In the examined building a wide simulation analysis has shown the achievement of a very satisfying performance. Furthermore, the effectiveness of the system can be maximized by means of active or semi-active devices implemented in the floating roof and a significant reduction of the seismic impact on the building can be obtained compared with non-controlled or simply passively controlled structure. The results prove the remarkable increase of the energy dissipation capability of the system, as well as the reduction of structural damage, independently of any specific strengthening intervention

  1. Integrated Seismic Survey for Detecting Landslide Effects on High Speed Rail Line at Istanbul–Turkey

    Directory of Open Access Journals (Sweden)

    Grit Mert

    2016-02-01

    Full Text Available In this study, Multichannel Analysis of Surface Waves Method (MASW, seismic refraction tomography and seismic reflection methods are used together at Silivri district in Istanbul – a district with a landslide problem because of the high speed rail line project crossing through the area. The landslide structure, border and depth of the slip plane are investigated and correlated within the local geology. According to the obtained 2D seismic sections, the landslide occurs through the East-West direction in the study area and the landslide slip plane with its border are clearly obtained under the subsurface. The results prove that the study area is suitable enough for the landslide development and this evolution also affects the high speed rail line project.

  2. Integral anomalous effect of an oil and gas deposit in a seismic wave field

    Energy Technology Data Exchange (ETDEWEB)

    Korostyshevskiy, M.B.; Nabokov, G.N.

    1981-01-01

    The basic precepts of an elaborated version of a procedure for forecasting (direct exploration) of oil and gas deposits according to seismic prospecting data MOV are examined. This procedure was previously called the procedure of analysis of the integral affect of an oil and gas deposit in a seismic wave field (MIIEZ-VP). The procedure is implemented in the form of an automated system ASOM-VP for the BESM-4 computer in a standard configuration equipped with standard input-output devices for seismic information (''Potok'', MVU, ''Atlas''). The entire procedure of processing from input of data into the computer to output of resulting maps and graphs on graph plotter ''Atlas'' is automated. Results of testing of procedure MIIEZ-VP and system ASOM-VP on drilled areas of Kazakhstan, Azerbaydzhan and Uzbekistan are cited.

  3. Effect of Soil-Structure Interaction on Seismic Performance of Long-Span Bridge Tested by Dynamic Substructuring Method

    Directory of Open Access Journals (Sweden)

    Zhenyun Tang

    2017-01-01

    Full Text Available Because of the limitations of testing facilities and techniques, the seismic performance of soil-structure interaction (SSI system can only be tested in a quite small scale model in laboratory. Especially for long-span bridge, a smaller tested model is required when SSI phenomenon is considered in the physical test. The scale effect resulting from the small scale model is always coupled with the dynamic performance, so that the seismic performance of bridge considering SSI effect cannot be uncovered accurately by the traditional testing method. This paper presented the implementation of real-time dynamic substructuring (RTDS, involving the combined use of shake table array and computational engines for the seismic simulation of SSI. In RTDS system, the bridge with soil-foundation system is divided into physical and numerical substructures, in which the bridge is seen as physical substructures and the remaining part is seen as numerical substructures. The interface response between the physical and numerical substructures is imposed by shake table and resulting reaction force is fed back to the computational engine. The unique aspect of the method is to simulate the SSI systems subjected to multisupport excitation in terms of a larger physical model. The substructuring strategy and the control performance associated with the real-time substructuring testing for SSI were performed. And the influence of SSI on a long-span bridge was tested by this novel testing method.

  4. The Effect of Boiling on Seismic Properties of Water-Saturated Fractured Rock

    Science.gov (United States)

    Grab, Melchior; Quintal, Beatriz; Caspari, Eva; Deuber, Claudia; Maurer, Hansruedi; Greenhalgh, Stewart

    2017-11-01

    Seismic campaigns for exploring geothermal systems aim at detecting permeable formations in the subsurface and evaluating the energy state of the pore fluids. High-enthalpy geothermal resources are known to contain fluids ranging from liquid water up to liquid-vapor mixtures in regions where boiling occurs and, ultimately, to vapor-dominated fluids, for instance, if hot parts of the reservoir get depressurized during production. In this study, we implement the properties of single- and two-phase fluids into a numerical poroelastic model to compute frequency-dependent seismic velocities and attenuation factors of a fractured rock as a function of fluid state. Fluid properties are computed while considering that thermodynamic interaction between the fluid phases takes place. This leads to frequency-dependent fluid properties and fluid internal attenuation. As shown in a first example, if the fluid contains very small amounts of vapor, fluid internal attenuation is of similar magnitude as attenuation in fractured rock due to other mechanisms. In a second example, seismic properties of a fractured geothermal reservoir with spatially varying fluid properties are calculated. Using the resulting seismic properties as an input model, the seismic response of the reservoir is then computed while the hydrothermal structure is assumed to vary over time. The resulting seismograms demonstrate that anomalies in the seismic response due to fluid state variability are small compared to variations caused by geological background heterogeneity. However, the hydrothermal structure in the reservoir can be delineated from amplitude anomalies when the variations due to geology can be ruled out such as in time-lapse experiments.

  5. 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)

  6. Mobility Effect on Poroelastic Seismic Signatures in Partially Saturated Rocks With Applications in Time-Lapse Monitoring of a Heavy Oil Reservoir

    Science.gov (United States)

    Zhao, Luanxiao; Yuan, Hemin; Yang, Jingkang; Han, De-hua; Geng, Jianhua; Zhou, Rui; Li, Hui; Yao, Qiuliang

    2017-11-01

    Conventional seismic analysis in partially saturated rocks normally lays emphasis on estimating pore fluid content and saturation, typically ignoring the effect of mobility, which decides the ability of fluids moving in the porous rocks. Deformation resulting from a seismic wave in heterogeneous partially saturated media can cause pore fluid pressure relaxation at mesoscopic scale, thereby making the fluid mobility inherently associated with poroelastic reflectivity. For two typical gas-brine reservoir models, with the given rock and fluid properties, the numerical analysis suggests that variations of patchy fluid saturation, fluid compressibility contrast, and acoustic stiffness of rock frame collectively affect the seismic reflection dependence on mobility. In particular, the realistic compressibility contrast of fluid patches in shallow and deep reservoir environments plays an important role in determining the reflection sensitivity to mobility. We also use a time-lapse seismic data set from a Steam-Assisted Gravity Drainage producing heavy oil reservoir to demonstrate that mobility change coupled with patchy saturation possibly leads to seismic spectral energy shifting from the baseline to monitor line. Our workflow starts from performing seismic spectral analysis on the targeted reflectivity interface. Then, on the basis of mesoscopic fluid pressure diffusion between patches of steam and heavy oil, poroelastic reflectivity modeling is conducted to understand the shift of the central frequency toward low frequencies after the steam injection. The presented results open the possibility of monitoring mobility change of a partially saturated geological formation from dissipation-related seismic attributes.

  7. Multicomponent seismic applications in coalbed methane development

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, D.; Trend, S. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics

    2004-07-01

    Seismic applications for coalbed methane (CBM) development are used to address the following challenges: lateral continuity of coal zones; vertical continuity of coal seams; permeability of cleats and fractures; coal quality and gas content; wet versus dry coal zones; and, monitoring storage of greenhouse gases. This paper presented a brief description of existing seismic programs, including 2-D and 3-D surface seismic surveys; multicomponent seismic surveys; vertical seismic profiles; cross-well seismic surveys; and, time-lapse seismic surveys. A comparative evaluation of their use in the Horseshoe Canyon Formation and the Ardley Formation was presented. The study showed that variations in reservoir properties resulting from gas production and dewatering can be effectively imaged using seismic surveys. Seismic surveys are useful in reservoir management, monitoring sweep efficiency during enhanced natural gas from coal (NGC) production, monitoring disposal of produced water and verifying storage of carbon dioxide for carbon credits. tabs., figs.

  8. Numerical Analysis of Slopes Stability and Shallow Foundations Behavior at Crest under Real Seismic Loading - Reinforcement Effect

    International Nuclear Information System (INIS)

    Mekdash, H.; Hage Chehade, F.; Sadek, M.; Abdel Massih, D.; El Hachem, E.; Youssef, E.

    2011-01-01

    The aim of this paper is to analyze the slopes stability under seismic loading using a global numerical dynamic approach. This approach allows important parameters that are generally ignored by traditional engineering methods such as the soil deformability, the dynamic amplification, non linear soil behavior, the spatial and temporal variability of the seismic loading and the reinforcement element. The present study is conducted by using measures recorded during real earthquakes (Turkey, 1999) and (Lebanon, 2008). Elastoplastic soil behavior analysis leads to monitor the evolution of the slope state after an earthquake and to clarify the most probable failure circles. A parametric study according to the reinforcement length, position, inclination and the number of elements has been studied in order to define the optimal reinforcement scheme for slopes under seismic loading. This study contains also the stability analysis of an existing foundation near the slope's crest. It will focus on the reinforcement in order to give recommendation for the most appropriate scheme that minimize the settlement of the foundation due to earthquake effect. (author)

  9. Reference frame access under the effects of great earthquakes: a least squares collocation approach for non-secular post-seismic evolution

    Science.gov (United States)

    Gómez, D. D.; Piñón, D. A.; Smalley, R.; Bevis, M.; Cimbaro, S. R.; Lenzano, L. E.; Barón, J.

    2016-03-01

    The 2010, (Mw 8.8) Maule, Chile, earthquake produced large co-seismic displacements and non-secular, post-seismic deformation, within latitudes 28°S-40°S extending from the Pacific to the Atlantic oceans. Although these effects are easily resolvable by fitting geodetic extended trajectory models (ETM) to continuous GPS (CGPS) time series, the co- and post-seismic deformation cannot be determined at locations without CGPS (e.g., on passive geodetic benchmarks). To estimate the trajectories of passive geodetic benchmarks, we used CGPS time series to fit an ETM that includes the secular South American plate motion and plate boundary deformation, the co-seismic discontinuity, and the non-secular, logarithmic post-seismic transient produced by the earthquake in the Posiciones Geodésicas Argentinas 2007 (POSGAR07) reference frame (RF). We then used least squares collocation (LSC) to model both the background secular inter-seismic and the non-secular post-seismic components of the ETM at the locations without CGPS. We tested the LSC modeled trajectories using campaign and CGPS data that was not used to generate the model and found standard deviations (95 % confidence level) for position estimates for the north and east components of 3.8 and 5.5 mm, respectively, indicating that the model predicts the post-seismic deformation field very well. Finally, we added the co-seismic displacement field, estimated using an elastic finite element model. The final, trajectory model allows accessing the POSGAR07 RF using post-Maule earthquake coordinates within 5 cm for ˜ 91 % of the passive test benchmarks.

  10. Microstructure and Thermo-Hydro-Mechanical effects as an explanation for rate dependency during seismic slip

    Science.gov (United States)

    Stefanou, I.; Rattez, H.; Sulem, J.

    2017-12-01

    Rapid shear tests of granulated fault gouges show pronounced rate-dependency. For this reason rate-dependent constitutive laws are frequently used for describing fault friction.Here we propose a micromechanical, physics-based continuum approach by considering the characteristic size of the microstructure and the thermal- and pore-pressure-diffusion mechanisms that take place in the fault gouge during rapid shearing. It is shown that even for rate-independent materials, the apparent, macroscopic behavior of the system is rate-dependent. This is due to the competition of the characteristic lengths and time scales introduced indirectly by the microstructure and the thermal and hydraulic diffusivities.Both weakening and shear band thickness are rate dependent, despite the fact that the constitutive description of the material was considered rate-independent. Moreover the size of the microstructure, which here is identified with the grain size of the fault gouge (D50), plays an important role in the slope of the softening branch of the shear stress-strain response curve and consequently in the transition from aseismic to seismic slip.References Dieterich, J. H. (1979). Modeling of rock friction: 1. Experimental results and constitutive equations. Journal of Geophysical Research, 84(B5), 2161. http://doi.org/10.1029/JB084iB05p02161 Scholz, C. H. (2002). The mechanics of earthquakes and faulting (Second). Cambridge. Sulem, J., & Stefanou, I. (2016). Thermal and chemical effects in shear and compaction bands. Geomechanics for Energy and the Environment, 6, 4-21. http://doi.org/10.1016/j.gete.2015.12.004

  11. Effects of Permafrost and Seasonally Frozen Ground on the Seismic Responses of Transportation Infrastructure Sites

    Science.gov (United States)

    2010-02-01

    The state of Alaska is located in one of the most seismically active zones in the world. Several large magnitude earthquakes (the Prince William Sound Earthquake, March 1964 and the Denali Earthquake, November 2002) have occurred in the state and cau...

  12. Crack-induced anisotropy and its effect on vertical seismic profiling

    NARCIS (Netherlands)

    Douma, J.

    1988-01-01

    Media containing aligned rotationally symmetrical inclusions show transverse isotropy with respect to elastic wave propagation. The characteristics of this type of anisotropy have been investigated in the first part of this thesis (chapters 2, 3, and 4) while its implications on Vertical Seismic

  13. Effect of fault roughness on aftershock distribution and post co-seismic strain accumulation.

    Science.gov (United States)

    Aslam, K.; Daub, E. G.

    2017-12-01

    We perform physics-based simulations of earthquake rupture propagation on geometrically complex strike-slip faults. We consider many different realization of the fault roughness and obtain heterogeneous stress fields by performing dynamic rupture simulation of large earthquakes. We calculate the Coulomb failure function (CFF) for all these realizations so that we can quantify zones of stress increase/shadows surrounding the main fault and compare our results to seismic catalogs. To do this comparison, we use relocated earthquake catalogs from Northern and Southern California. We specify the range of fault roughness parameters based on past observational studies. The Hurst exponent (H) varies in range from 0.5 to 1 and RMS height to wavelength ratio ( RMS deviation of a fault profile from planarity) has values between 10-2 to 10-3. For any realization of fault roughness, the Probability density function (PDF) values relative to the mean CFF change show a wider spread near the fault and this spread squeezes into a narrow band as we move away from fault. For lower value of RMS ratio ( 10-3), we see bigger zones of stress change near the hypocenter and for higher value of RMS ratio ( 10-2), we see alternate zones of stress increase/decrease surrounding the fault to have comparable lengths. We also couple short-term dynamic rupture simulation with long-term tectonic modelling. We do this by giving the stress output from one of the dynamic rupture simulation (of a single realization of fault roughness) to long term tectonic model (LTM) as initial condition and then run LTM over duration of seismic cycle. This short term and long term coupling enables us to understand how heterogeneous stresses due to fault geometry influence the dynamics of strain accumulation in the post-seismic and inter-seismic phase of seismic cycle.

  14. Time lapse seismic observations and effects of reservoir compressibility at Teal South oil field

    Science.gov (United States)

    Islam, Nayyer

    One of the original ocean-bottom time-lapse seismic studies was performed at the Teal South oil field in the Gulf of Mexico during the late 1990's. This work reexamines some aspects of previous work using modern analysis techniques to provide improved quantitative interpretations. Using three-dimensional volume visualization of legacy data and the two phases of post-production time-lapse data, I provide additional insight into the fluid migration pathways and the pressure communication between different reservoirs, separated by faults. This work supports a conclusion from previous studies that production from one reservoir caused regional pressure decline that in turn resulted in liberation of gas from multiple surrounding unproduced reservoirs. I also provide an explanation for unusual time-lapse changes in amplitude-versus-offset (AVO) data related to the compaction of the producing reservoir which, in turn, changed an isotropic medium to an anisotropic medium. In the first part of this work, I examine regional changes in seismic response due to the production of oil and gas from one reservoir. The previous studies primarily used two post-production ocean-bottom surveys (Phase I and Phase II), and not the legacy streamer data, due to the unavailability of legacy prestack data and very different acquisition parameters. In order to incorporate the legacy data in the present study, all three post-stack data sets were cross-equalized and examined using instantaneous amplitude and energy volumes. This approach appears quite effective and helps to suppress changes unrelated to production while emphasizing those large-amplitude changes that are related to production in this noisy (by current standards) suite of data. I examine the multiple data sets first by using the instantaneous amplitude and energy attributes, and then also examine specific apparent time-lapse changes through direct comparisons of seismic traces. In so doing, I identify time-delays that, when

  15. Seismic Studies

    Energy Technology Data Exchange (ETDEWEB)

    R. Quittmeyer

    2006-09-25

    This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground

  16. Seismic Studies

    International Nuclear Information System (INIS)

    R. Quittmeyer

    2006-01-01

    This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground motion at

  17. Interaction between two subducting plates under Tokyo and its possible effects on seismic hazards

    Science.gov (United States)

    Wu, Francis; Okaya, David; Sato, Hiroshi; Hirata, Naoshi

    2007-09-01

    Underneath metropolitan Tokyo the Philippine Sea plate (PHS) subducts to the north on top of the westward subducting Pacific plate (PAC). New, relatively high-resolution tomography images the PHS as a well-defined subduction zone under western Kanto Plain. As PAC shoals under eastern Kanto, the PHS lithosphere is being thrusted into an increasingly tighter space of the PAC-Eurasian mantle wedge. As a result, zones of enhanced seismicity appear under eastern Kanto at the top of PHS, internal to PHS and also at its contact with PAC. These zones are located at depths greater than the causative fault of the disastrous 1923 Great Tokyo ``megathrust'' earthquake, in the vicinity of several well-located historical, damaging (M6 and M7) earthquakes. Thus a rather unique interaction between subducting plates under Tokyo may account for additional seismic hazards in metropolitan Tokyo.

  18. Analysis of confinement effects for in-water seismic tests on PWR fuel assemblies

    International Nuclear Information System (INIS)

    Broc, Daniel; Queval, Jean-Claude; Rigaudeau, J.; Viallet, E.

    2001-01-01

    In the framework of a comprehensive program on the seismic behaviour of the PWR reactor cores, tests have been performed on a row of six PWR fuel assemblies, with two confinement configurations in water. Global fluid motion along the row is not allowed in the 'full confinement configuration', and is allowed in the 'lateral confinement configuration'. The seismic test results show that the impact forces at assembly grid levels are significantly smaller with the full confinement. This is due to damping, which is found to be larger in this configuration where the average fluid velocity inside the assembly (around the rods) is itself larger. We present analyses of these phenomena from theoretical and experimental standpoint. This involves both fluid models and structural models of the assembly row. (author)

  19. Distance effects on regional discriminants along a seismic profile in Northwest Nevada; NPE and nuclear results

    Energy Technology Data Exchange (ETDEWEB)

    McCormack, D.A. [AWE Blacknest, Berkshire (United Kingdom); Priestley, K.F. [Univ. of Cambridge (United Kingdom); Patton, H.J. [Lawrence Livermore National Lab., CA (United States)

    1994-12-31

    To address questions of discriminant transportability, it is important to understand how discriminants based on regional seismic phases are affected by regional variations in velocity structure. To examine this issue, we have recorded two explosions, the nuclear explosion Kinibito and the Non-Proliferation Experiment along a 300 km-long profile through western Nevada. We use these data to investigate the stability with distance of several proposed seismic discriminants. In this study we first estimate the apparent attenuation of the regional phases. We compare attenuation corrected amplitude ratios for P{sub n}/L{sub g} and P{sub g}/L{sub g}, and spectral ratios for P{sub n}, P{sub g}, and L{sub g}, as a function of distance along the profile. We make these comparisons for the vertical component and for the total vector resultant using all three components of motion.

  20. The effect of Earth's oblateness on the seismic moment estimation from satellite gravimetry

    Science.gov (United States)

    Dai, Chunli; Guo, Junyi; Shang, Kun; Shum, C. K.; Wang, Rongjiang

    2018-05-01

    Over the last decade, satellite gravimetry, as a new class of geodetic sensors, has been increasingly studied for its use in improving source model inversion for large undersea earthquakes. When these satellite-observed gravity change data are used to estimate source parameters such as seismic moment, the forward modelling of earthquake seismic deformation is crucial because imperfect modelling could lead to errors in the resolved source parameters. Here, we discuss several modelling issues and focus on one modelling deficiency resulting from the upward continuation of gravity change considering the Earth's oblateness, which is ignored in contemporary studies. For the low degree (degree 60) time-variable gravity solutions from Gravity Recovery and Climate Experiment mission data, the model-predicted gravity change would be overestimated by 9 per cent for the 2011 Tohoku earthquake, and about 6 per cent for the 2010 Maule earthquake. For high degree gravity solutions, the model-predicted gravity change at degree 240 would be overestimated by 30 per cent for the 2011 Tohoku earthquake, resulting in the seismic moment to be systematically underestimated by 30 per cent.

  1. Effect of Vertically Propagating Shear Waves on Seismic Behavior of Circular Tunnels

    Directory of Open Access Journals (Sweden)

    Tohid Akhlaghi

    2014-01-01

    Full Text Available Seismic design loads for tunnels are characterized in terms of the deformations imposed on the structure by surrounding ground. The free-field ground deformations due to a seismic event are estimated, and the tunnel is designed to accommodate these deformations. Vertically propagating shear waves are the predominant form of earthquake loading that causes the ovaling deformations of circular tunnels to develop, resulting in a distortion of the cross sectional shape of the tunnel lining. In this paper, seismic behavior of circular tunnels has been investigated due to propagation of shear waves in the vertical direction using quasi-static analytical approaches as well as numerical methods. Analytical approaches are based on the closed-form solutions which compute the forces in the lining due to equivalent static ovaling deformations, while the numerical method carries out dynamic, nonlinear soil-structure interaction analysis. Based on comparisons made, the accuracy and reliability of the analytical solutions are evaluated and discussed. The results show that the axial forces determined using the analytical approaches are in acceptable agreement with numerical analysis results, while the computed bending moments are less comparable and show significant discrepancies. The differences between the analytical approaches are also investigated and addressed.

  2. Effectiveness of Tuned Mass Dampers in Seismic Response Control of Isolated Bridges Including Soil-Structure Interaction

    Directory of Open Access Journals (Sweden)

    Said Elias

    Full Text Available Abstract The effect of soil-structure interaction (SSI on the dynamic responses of seismically isolated three-span continuous reinforced concrete (RC bridge is investigated. Also, tuned mass damper(s (TMD/s is/are installed to control undesirable bearing displacement, even under the SSI effect. The TMDs are placed at the mid-span of the bridge and each tuned with a modal frequency, while controlling up to first few modes as desirable. The soil surrounding the foundation of pier is modeled by frequency independent coefficients. Dynamic analysis is carried out in time domain using direct integration method. In order to specify the effects of the SSI, the responses of the non-isolated, isolated, and controlled isolated bridge are compared. It is observed that the soil surrounding the pier has significant effects on the bearing displacement of the isolated RC bridges. In addition, it is observed that the seismic responses of isolated RC bridge reduced significantly with installation of the TMDs.

  3. Annual Hanford seismic report - fiscal year 1996

    International Nuclear Information System (INIS)

    Hartshorn, D.C.; Reidel, S.P.

    1996-12-01

    Seismic monitoring (SM) at the Hanford Site was established in 1969 by the US Geological Survey (USGS) under a contract with the US Atomic Energy Commission. Since 1980, the program has been managed by several contractors under the US Department of Energy (USDOE). Effective October 1, 1996, the Seismic Monitoring workscope, personnel, and associated contracts were transferred to the USDOE Pacific Northwest National Laboratory (PNNL). SM is tasked to provide an uninterrupted collection and archives of high-quality raw and processed seismic data from the Hanford Seismic Network (HSN) located on and encircling the Hanford Site. SM is also tasked to locate and identify sources of seismic activity and monitor changes in the historical pattern of seismic activity at the Hanford Site. The data compiled are used by SM, Waste Management, and engineering activities at the Hanford Site to evaluate seismic hazards and seismic design for the Site

  4. Induced seismicity. Final report

    International Nuclear Information System (INIS)

    Segall, P.

    1997-01-01

    The objective of this project has been to develop a fundamental understanding of seismicity associated with energy production. Earthquakes are known to be associated with oil, gas, and geothermal energy production. The intent is to develop physical models that predict when seismicity is likely to occur, and to determine to what extent these earthquakes can be used to infer conditions within energy reservoirs. Early work focused on earthquakes induced by oil and gas extraction. Just completed research has addressed earthquakes within geothermal fields, such as The Geysers in northern California, as well as the interactions of dilatancy, friction, and shear heating, on the generation of earthquakes. The former has involved modeling thermo- and poro-elastic effects of geothermal production and water injection. Global Positioning System (GPS) receivers are used to measure deformation associated with geothermal activity, and these measurements along with seismic data are used to test and constrain thermo-mechanical models

  5. Seismic Symphonies

    Science.gov (United States)

    Strinna, Elisa; Ferrari, Graziano

    2015-04-01

    The project started in 2008 as a sound installation, a collaboration between an artist, a barrel organ builder and a seismologist. The work differs from other attempts of sound transposition of seismic records. In this case seismic frequencies are not converted automatically into the "sound of the earthquake." However, it has been studied a musical translation system that, based on the organ tonal scale, generates a totally unexpected sequence of sounds which is intended to evoke the emotions aroused by the earthquake. The symphonies proposed in the project have somewhat peculiar origins: they in fact come to life from the translation of graphic tracks into a sound track. The graphic tracks in question are made up by copies of seismograms recorded during some earthquakes that have taken place around the world. Seismograms are translated into music by a sculpture-instrument, half a seismograph and half a barrel organ. The organ plays through holes practiced on paper. Adapting the documents to the instrument score, holes have been drilled on the waves' peaks. The organ covers about three tonal scales, starting from heavy and deep sounds it reaches up to high and jarring notes. The translation of the seismic records is based on a criterion that does match the highest sounds to larger amplitudes with lower ones to minors. Translating the seismogram in the organ score, the larger the amplitude of recorded waves, the more the seismogram covers the full tonal scale played by the barrel organ and the notes arouse an intense emotional response in the listener. Elisa Strinna's Seismic Symphonies installation becomes an unprecedented tool for emotional involvement, through which can be revived the memory of the greatest disasters of over a century of seismic history of the Earth. A bridge between art and science. Seismic Symphonies is also a symbolic inversion: the instrument of the organ is most commonly used in churches, and its sounds are derived from the heavens and

  6. The Effects of Realistic Geological Heterogeneity on Seismic Modeling: Applications in Shear Wave Generation and Near-Surface Tunnel Detection

    Science.gov (United States)

    Sherman, Christopher Scott

    Naturally occurring geologic heterogeneity is an important, but often overlooked, aspect of seismic wave propagation. This dissertation presents a strategy for modeling the effects of heterogeneity using a combination of geostatistics and Finite Difference simulation. In the first chapter, I discuss my motivations for studying geologic heterogeneity and seis- mic wave propagation. Models based upon fractal statistics are powerful tools in geophysics for modeling heterogeneity. The important features of these fractal models are illustrated using borehole log data from an oil well and geomorphological observations from a site in Death Valley, California. A large part of the computational work presented in this disserta- tion was completed using the Finite Difference Code E3D. I discuss the Python-based user interface for E3D and the computational strategies for working with heterogeneous models developed over the course of this research. The second chapter explores a phenomenon observed for wave propagation in heteroge- neous media - the generation of unexpected shear wave phases in the near-source region. In spite of their popularity amongst seismic researchers, approximate methods for modeling wave propagation in these media, such as the Born and Rytov methods or Radiative Trans- fer Theory, are incapable of explaining these shear waves. This is primarily due to these method's assumptions regarding the coupling of near-source terms with the heterogeneities and mode conversion. To determine the source of these shear waves, I generate a suite of 3D synthetic heterogeneous fractal geologic models and use E3D to simulate the wave propaga- tion for a vertical point force on the surface of the models. I also present a methodology for calculating the effective source radiation patterns from the models. The numerical results show that, due to a combination of mode conversion and coupling with near-source hetero- geneity, shear wave energy on the order of 10% of the

  7. Evaluation of seismic effects on the landslide deposits of Monte Salta (Eastern Italian Alps) using distinct element method

    Science.gov (United States)

    Marcato, G.; Fujisawa, K.; Mantovani, M.; Pasuto, A.; Silvano, S.; Tagliavini, F.; Zabuski, L.

    2007-11-01

    The aim of the paper is to present the modelling of the ground effects of seismic waves on a large debris deposit lying on a steep mountain slope, with particular attention paid to the potential triggering of slope movements. The study site is a mass of 2.5 million m3 rock fall deposit, named "Monte Salta Landslide", located on the northern slope of the Vajont valley, at the border between Veneto and Friuli Venezia Giulia regions in north-eastern Italy. Several historical landslide events were reported in the area in the past, first one dating back to the 17th century. The landslide deposit completely mantles the slope with a thick cover of rock blocks. The Mt. Salta landslide is conditioned by the presence of Mt. Borgà regional thrust, which uplifts Jurassic limestone on the top of Cretaceous rock units. Above the thrust zone, folded and highly fractured rock mass dips steeply towards the slope free face, producing highly unstable setting. The study area has been classified as high seismic hazard and different vulnerable elements can be affected by the remobilisation of debris, among which a village, a national road and a big quarry that was opened, with the intent to exploit the part of the landslide deposit for construction purposes. In this study, numerical analysis was performed, to simulate the slope behaviour using distinct element method and applying UDEC code. The 2-D models were built on three cross-sections and elasto-plastic behaviour was assumed, both for rock matrix and discontinuities. The earthquake effect was modelled in pseudo-dynamic way, i.e. by magnifying the acceleration and applying also its horizontal component. The expected seismic acceleration in the study area was calculated on the basis of previous studies as equal to 0.28 g. The results proved that the increase of the vertical component alone has a small influence on the deformational behaviour of the system. Hence, the acceleration vector was deviated at 5° and then at 10° from the

  8. Evaluation of seismic effects on the landslide deposits of Monte Salta (Eastern Italian Alps using distinct element method

    Directory of Open Access Journals (Sweden)

    G. Marcato

    2007-11-01

    Full Text Available The aim of the paper is to present the modelling of the ground effects of seismic waves on a large debris deposit lying on a steep mountain slope, with particular attention paid to the potential triggering of slope movements.

    The study site is a mass of 2.5 million m3 rock fall deposit, named "Monte Salta Landslide", located on the northern slope of the Vajont valley, at the border between Veneto and Friuli Venezia Giulia regions in north-eastern Italy.

    Several historical landslide events were reported in the area in the past, first one dating back to the 17th century. The landslide deposit completely mantles the slope with a thick cover of rock blocks.

    The Mt. Salta landslide is conditioned by the presence of Mt. Borgà regional thrust, which uplifts Jurassic limestone on the top of Cretaceous rock units. Above the thrust zone, folded and highly fractured rock mass dips steeply towards the slope free face, producing highly unstable setting.

    The study area has been classified as high seismic hazard and different vulnerable elements can be affected by the remobilisation of debris, among which a village, a national road and a big quarry that was opened, with the intent to exploit the part of the landslide deposit for construction purposes.

    In this study, numerical analysis was performed, to simulate the slope behaviour using distinct element method and applying UDEC code. The 2-D models were built on three cross-sections and elasto-plastic behaviour was assumed, both for rock matrix and discontinuities. The earthquake effect was modelled in pseudo-dynamic way, i.e. by magnifying the acceleration and applying also its horizontal component. The expected seismic acceleration in the study area was calculated on the basis of previous studies as equal to 0.28 g.

    The results proved that the increase of the vertical component alone has a small influence on the deformational behaviour of the

  9. Understanding induced seismicity

    NARCIS (Netherlands)

    Elsworth, Derek; Spiers, Christopher J.|info:eu-repo/dai/nl/304829323; Niemeijer, Andre R.|info:eu-repo/dai/nl/370832132

    2016-01-01

    Fluid injection–induced seismicity has become increasingly widespread in oil- and gas-producing areas of the United States (1–3) and western Canada. It has shelved deep geothermal energy projects in Switzerland and the United States (4), and its effects are especially acute in Oklahoma, where

  10. Effect of foundation embedment on the seismic response of a high-temperature gas-cooled reactor plant

    International Nuclear Information System (INIS)

    Lee, T.H.; Thompson, R.W.; Charman, C.M.

    1983-01-01

    The effects of soil-structure interaction during seismic events upon the dynamic response of a High Temperature Gas-Cooled Reactor plant (HTGR) have been investigated for both surface-founded and embedded basemats. The influence from foundation embedment has been quantitatively assessed through a series of theoretical studies on plants of various sizes. The surface-founded analyses were performed using frequency-independent soil impedance parameters, while the embedded plant analyses utilized finite element models simulated on the FLUSH computer program. The seismic response of the surface-founded plants has been used to establish the standard-site design in-structure response spectra. These analyses were performed by using the linear modal formulation based on conventional soil stiffness and damping values. They serve as reference solutions to which the response data of the corresponding embedded plants are compared. In these comparison studies the responses of embedded plants were generally found to be lower than those of the corresponding surface-founded plants. Additional studies on the surface-founded plants have recently been performed by considering inelastic soil behavior. These inelastic solutions, which treat the soil as an elasto-plastic medium exhibiting hysteretic unloading-reloading characteristics in time, have reduced the response of surface-founded plants. Numerical results are presented in terms of in-structure response spectra along with other pertinent seismic load data at key levels of the plant. Analysis techniques for future studies using viscoelastic halfspace representation and inelastic finite element modeling for soil are also discussed

  11. The revaluation of the macroseismic effects of March 4, 1977 earthquake in the frame of the new seismic hazard assessment methodologies

    International Nuclear Information System (INIS)

    Pantea, A.; Constantin, Angela; Anghel, M.

    2002-01-01

    To increase the earthquakes resistance of structure the design norms and construction require the best knowledge of seismic hazard parameters and using the new methodologies of seismic hazard assessment. One of these parameters is seismic intensity of the earthquakes occurred on the whole territory analyzed during as long as possible time interval for which data are available, especially for the strongest of them. For Romanian territory the strongest and the best known from the point of view of the macroseismic effects is the March 4, 1977 earthquake. Seismology by itself, without geophysics (solid earth physics), geology, geography, and geodesy, cannot fully, comprehensively, validly assess seismic hazards. Among those who have understood seismic hazard assessment as the result of cooperation between geosciences as a whole and seismology, one may quote Bune, 1978; Pantea et al., 2002, etc. Assessing seismic hazards is a complex undertaking, for it draws on a vast amount of knowledge in numerous sectors of geosciences, particularly solid earth physics as a branch of geophysics that also includes seismology, tectonic physics, gravimetry, geomagnetism, geochronology, etc.. It involves processing the results of complex geophysical, seismologic, tectonic, and geologic studies. To get a picture of, and understand, the laws that govern seismogenesis, one has to know what the relations are among the measured physical quantities indicating the properties of the rocks (whether gravimetric, magnetometric, electrometric, seismometric, or others), the dynamics of tectonic structures, as well as the nature and geological characteristics. Geophysics can be relied upon to determine the deep internal structure of the earth that geological methods are unable to reveal. Geophysics, and implicitly seismology, can help resolve the problem by: 1. Identifying the areas of the seismic sources and their characteristics, including focal depth, M max [Bune, 1978], and the recurrence chart

  12. Soil-structure interaction effects in seismic analysis of turbine generator building on rock-like foundation

    International Nuclear Information System (INIS)

    Park, Chi Seon; Lee, Sang Hoon; Yoo, Kwang Hoon

    2004-01-01

    Soil properties supporting structure may become criteria determining methodologies for seismic response analysis of a structure. Regulatory Guide describes that a fixed-base assumption is acceptable for structures supported on rock or rock-like materials defined by a shear wave velocity of 3,500 ft/sec or greater at a shear strain of 10 -3 percent or smaller when considering preloaded soil conditions due to the structure. Seismic analyses for the Korean nuclear power plant (NPP) structures satisfying the above site soil condition have been completed through the fixed-base analysis. However, dynamic responses for relatively stiff structures such as NPP structures still have soil-structure interaction (SSI) effects. In other words, the fixed-base analysis does not always yield conservative results to be compared with SSI analysis. The SSI effects due to different stiff soil properties for Turbine Generator Building (TGB) structure to be constructed at Kori site of South Korea are investigated in views of floor response spectra (FRS) and member forces

  13. Effect of soil-structure interaction on the seismic behaviour of pedestal-structure system in large dish antennas

    Directory of Open Access Journals (Sweden)

    Bahador Pourhatami

    2017-12-01

    Full Text Available Regarding the progressive improvement in the territory of Space Technology in all developed countries and consequently developing countries including Islamic Republic of Iran, the optimization of design and utilization of the communication equipment has been paid more attention today. For instance, considering recent highly innovative methods, specifically in communication field, developed for design, manufacturing and exploiting dish antenna for specific cases, cooperation of other science and technology experts, like civil engineers, is also necessary. In this way, more delicate design procedure in order to satisfy communication requirement, is achieved. So far, no specific investigation about aforementioned subject, especially the effect of soil-structure interaction (SSI in analysing the seismic behaviour of communication large dish antennas has been conducted in Iran. In this paper, with the aim of investigating the effect of SSI on seismic behavior of pedestal, first an acceptable range for antenna displacement – as the most important parameter in pedestal structure for antenna – in both operational and survival states, has been calculated numerically based on generic formula. Secondly, the modelling of the whole pedestal-structure system has been modelled subjected to the associated loads and other primary conditions. This procedure has been performed once without considering the SSI and once more with it. Comparison of the obtained results shows that considering the SSI would impress the output results with a difference rate more than 50% and 600% respectively at survival and operational condition.

  14. Seismic Discrimination

    Science.gov (United States)

    1979-09-30

    were presumed nuclear explosions announced by ERDA. Of the last, 11 were at the Semipalatinsk test site , 2 at the Western Kazakh test site , 2 in Novaya...which will fulfill U.S. ob- ligations that may be incurred under a possible future Comprehensive Test Ban Treaty. This report includes 9 contributions...which could assume U.S. seismic-data-management responsibilities in the event that international agreement is reached on a Comprehensive Test Ban

  15. Effect of Ground Motion Characteristics on the Seismic Response of a Monumental Concrete Arch Bridge

    Science.gov (United States)

    Caglayan, B. Ozden; Ozakgul, Kadir; Tezer, Ovunc

    2008-07-01

    Railway network in Turkey dates back to more than a hundred years ago and according to official records, there are approximately 18,000 railway bridges with spans varying between 50 cm up to 150 meters. One of them is a monumental concrete arch bridge with a total length of 210 meters having three major spans of 30 meters and a height of 65 meters, located in an earthquake-prone region in southern part of the country. Three-dimensional finite element model of the bridge was generated using a commercially available general finite element analysis software and based on the outcomes of a series of in-depth acceleration measurements that were conducted on-site, the model was refined. Types of ground motion records were used to investigate the seismic response and vulnerability of this massive structure in order to provide information regarding (i) damage-susceptible regions of the structure for monitoring purposes, and, (ii) seismic loads to be taken into account during evaluation and possible strengthening phases for this type of structures.

  16. Effect of Ground Motion Characteristics on the Seismic Response of a Monumental Concrete Arch Bridge

    International Nuclear Information System (INIS)

    Caglayan, B. Ozden; Ozakgul, Kadir; Tezer, Ovunc

    2008-01-01

    Railway network in Turkey dates back to more than a hundred years ago and according to official records, there are approximately 18,000 railway bridges with spans varying between 50 cm up to 150 meters. One of them is a monumental concrete arch bridge with a total length of 210 meters having three major spans of 30 meters and a height of 65 meters, located in an earthquake-prone region in southern part of the country. Three-dimensional finite element model of the bridge was generated using a commercially available general finite element analysis software and based on the outcomes of a series of in-depth acceleration measurements that were conducted on-site, the model was refined. Types of ground motion records were used to investigate the seismic response and vulnerability of this massive structure in order to provide information regarding (i) damage-susceptible regions of the structure for monitoring purposes, and, (ii) seismic loads to be taken into account during evaluation and possible strengthening phases for this type of structures

  17. 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.

  18. Study of the spectral ratios derived from seismic refraction data for evaluation of the local seismic effects in six sites between south of Mizil and west of Giurgiu

    International Nuclear Information System (INIS)

    Raileanu, Victor

    2002-01-01

    An analysis of spectral ratios derived from seismic records along the seismic refraction line Vrancea 99 is performed for six sites located south of Mizil. Records generated by four big shots (300 - 900 Kg charge) are analyzed in each size and 24 curves of spectral ratios are obtained. A first sight shows that the spectral ratios depend not only on the local geological and physical conditions but also on epicentral distance from source to the site as well as the magnitude of the released energy by the seismic source. Nevertheless it is noticed that the frequency windows with the high spectral ratios are about the same regardless of the position and magnitude of the source which suggests the influence of the local conditions. Generally, the sites from the north of Bucharest city, namely Parepa Rusani, Gradistea and Pantelimon show low spectral ratios while the southern sites, Singureni, Stanesti and Gaujani present higher spectral ratios in the frequency window from 0.1 - 10 Hz. The northern group of sites presents a diminution of the spectral ratios from about 2 Hz (0.5 s) to 7 - 8 Hz ( 0.14 - 0.12 s). The southern group has the peaks of spectral ratios within a better individualized frequency window, 3-6 Hz (0.33 - 0.16 s). A secondary peak is around 12 - 13 Hz (∼ 0.08 s). Such quite high resonance frequencies are generated by the shallow layers with thicknesses from a few tens meters (0.08 s corresponds to 32 m thickness) to one - two hundred meters (0.16/0.33/0.5 s → 60, 120, 190 m thickness). (author)

  19. Effect of Seepage on Change in Stress Distribution Scenario in Static and Seismic Behaviour of Earthen Dams

    Directory of Open Access Journals (Sweden)

    Nandi N.

    2018-02-01

    Full Text Available The present study makes an effort to understand the damage of earthen dams under static and seismic loading condition. To make the investigation more realistic, behaviour of earthen dams considering the occurrence of a phreatic line indicating the submerged zone due to seepage within the dam body is considered. In case of earthen dams, homogeneous or nonhomogeneous, the consideration of the occurrence of a phreatic line or seepage line through the dam body is an important part of the earthen dam design methodology. The impervious material properties in the submerged zone below the phreatic line due to seepage may differ a lot in magnitudes as compared to the value of the same materials lying above this line. Hence, to have the exact stress distribution scenarios within the earthen dam, the different material properties above and below the phreatic line are considered in this present study. The study is first carried out by two-dimensional as well as three-dimensional finite element analysis under static loading condition. The work is further extended to observe the effect of seepage due to the consideration of the phreatic line on dynamic characteristics of earthen dams. Free vibration analysis and seismic analysis based on the Complete Quadratic Combination (CQC method by considering twodimensional and three-dimensional modeling are carried out to present the frequencies, mode shapes and the stress distribution pattern of the earthen dam.

  20. Effect of Spin Transition onComposition and Seismic Structure of the Lower Mantle

    Science.gov (United States)

    Wu, Z.

    2015-12-01

    Spin transition of iron in ferropericlase (Fp) causes a significant softening in bulk modulus [e.g.,1,2], which leads to unusual dVP/dT>0. Because dVP/dT>0 in Fp cancels out with dVP/dTMao, Z., Marquardt, H., 2013. . Rev Geophys 51, 244-275 (2013). [3] Wu, Z.Q., Wentzcovitch, R.M., 2014. Spin crossover in ferropericlase and velocity heterogeneities in the lower mantle. Proc. Natl. Acad. Sci. U. S. A. 111, 10468-10472. [4] Zhao, D.P., 2007. Seismic images under 60 hotspots: Search for mantle plumes. Gondwana Res 12, 335-355. [5] van der Hilst, R.D., Karason, H., 1999. Science 283, 1885-1888. [6] Huang,C., Leng, W., Wu, Z. Q., 2015. Iron-spin transition controls structure and stability of LLSVPs in the lower mantle, Earth Planet. Sci. Lett. 423, 173-181.

  1. EFFECTS OF PARAMETRIC VARIATIONS ON SEISMIC ANALYSIS METHODS FOR NON-CLASSICALLY DAMPED COUPLED SYSTEMS

    International Nuclear Information System (INIS)

    XU, J.; DEGRASSI, G.

    2000-01-01

    A comprehensive benchmark program was developed by Brookhaven National Laboratory (BNL) to perform an evaluation of state-of-the-art methods and computer programs for performing seismic analyses of coupled systems with non-classical damping. The program, which was sponsored by the US Nuclear Regulatory Commission (NRC), was designed to address various aspects of application and limitations of these state-of-the-art analysis methods to typical coupled nuclear power plant (NPP) structures with non-classical damping, and was carried out through analyses of a set of representative benchmark problems. One objective was to examine the applicability of various analysis methods to problems with different dynamic characteristics unique to coupled systems. The examination was performed using parametric variations for three simple benchmark models. This paper presents the comparisons and evaluation of the program participants' results to the BNL exact solutions for the applicable ranges of modeling dynamic characteristic parameters

  2. Compositional trends among Kaapvaal Craton garnet peridotite xenoliths and their effects on seismic velocity and density

    DEFF Research Database (Denmark)

    Schutt, Derek; Lesher, Charles

    2010-01-01

    garnet and clinopyroxene enrichment. Using the parameterization of Schutt and Lesher (2006) we show that at cratonic mantle temperatures and pressures, orthopyroxene enrichment results in little change in bulk density (ρbulk) and shear-wave velocity (VS), but decreases compressional wave velocities (VP......We examine the modes and compositions of garnet-bearing peridotite xenoliths from the Kaapvaal Craton to quantify factors governing density and seismic velocity variations within metasomatically altered cratonic mantle. Three distinct compositional trends are resolved by principal component...... analysis. The first reflects differences in residue composition resulting from partial melting. The second is associated with orthopyroxene (opx) enrichment, possibly due to silica addition by subduction zone fluids in the source region of the xenoliths. The third principal component reflects garnet...

  3. Seismic efficiency of meteor airbursts

    Science.gov (United States)

    Svetsov, V. V.; Artemieva, N. A.; Shuvalov, V. V.

    2017-08-01

    We present the results of numerical simulation for impacts of relatively small asteroids and ice bodies of 30-100 m in size, decelerated in the atmosphere and exploding before they reach the surface, but still producing seismic effects due to the impact wave reaching the surface. The calculated magnitudes fall within the range of 4 to 6, and average seismic efficiency of these events is 2.5 × 10-5. The results obtained allow the seismic hazard from impacts of cosmic bodies to be estimated.

  4. Assessment of the Vibrations Effects Caused by Technical Seismicity Due to the Railway traffic on High-sensitivity Machinery

    Science.gov (United States)

    Papán, Daniel; Valašková, Veronika; Demeterová, Katarína

    2016-10-01

    The numerical and experimental approach in structural dynamics problems is more and more current nowadays. This approach is applied and solved in many research and developing institutions of the all the world. Vibrations effect caused by passing trains used in manufacturing facilities can affect the quality of the production activity. This effect is possible to be solved by a numerical or an experimental way. Numerical solution is not so financially and time demanding. The main aim of this article is to focus on just experimental measurement of this problem. In this paper, the case study with measurement due to cramped conditions realized in situ is presented. The case study is located close to railway. The vibration effect caused by passing trains on the high-sensitivity machinery contained in this object were observed. The structure was a high-sensitivity machine that was placed in a construction process. For the measurements, the high-sensitivity standard vibrations equipment was used. The assessments of measurements’ results were performed for the technological conditions and Slovak Standard Criteria. Both of these assessments were divided to amplitude and frequency domain. The amplitude criterion is also divided to peak particle velocity and RMS (Root Mean Square). Frequency domain assessment were realised using the frequency response curves obtained from high-sensitivity machinery manufacturer. The frequency limits are established for each axis of triaxle system. The measurement results can be predicted if the vibration have to be reduced. Measurement implemented in the production hall should obtain materials to determine the seismic loading and response of production machinery caused by technical seismicity.

  5. Seismic instrumentation

    International Nuclear Information System (INIS)

    1984-06-01

    RFS or Regles Fondamentales de Surete (Basic Safety Rules) applicable to certain types of nuclear facilities lay down requirements with which compliance, for the type of facilities and within the scope of application covered by the RFS, is considered to be equivalent to compliance with technical French regulatory practice. The object of the RFS is to take advantage of standardization in the field of safety, while allowing for technical progress in that field. They are designed to enable the operating utility and contractors to know the rules pertaining to various subjects which are considered to be acceptable by the Service Central de Surete des Installations Nucleaires, or the SCSIN (Central Department for the Safety of Nuclear Facilities). These RFS should make safety analysis easier and lead to better understanding between experts and individuals concerned with the problems of nuclear safety. The SCSIN reserves the right to modify, when considered necessary, any RFS and specify, if need be, the terms under which a modification is deemed retroactive. The aim of this RFS is to define the type, location and operating conditions for seismic instrumentation needed to determine promptly the seismic response of nuclear power plants features important to safety to permit comparison of such response with that used as the design basis

  6. Proposal for a model to assess the effect of seismic activity on the triggering of debris flows

    Science.gov (United States)

    Vidar Vangelsten, Bjørn; Liu, Zhongqiang; Eidsvig, Unni; Luna, Byron Quan; Nadim, Farrokh

    2013-04-01

    Landslide triggered by earthquakes is a serious threat for many communities around the world, and in some cases is known to have caused 25-50% of the earthquake fatalities. Seismic shaking can contribute to the triggering of debris flows either during the seismic event or indirectly by increasing the susceptibility of the slope to debris flow during intense rainfall in a period after the seismic event. The paper proposes a model to quantify both these effects. The model is based on an infinite slope formulation where precipitation and earthquakes influence the slope stability as follows: (1) During the shaking, the factor of safety is reduced due to cyclic pore pressure build-up where the cyclic pore pressure is modelled as a function of earthquake duration and intensity (measured as number of equivalent shear stress cycles and cyclic shear stress magnitude) and in-situ soil conditions (measured as average normalised shear stress). The model is calibrated using cyclic triaxial and direct simple shear (DSS) test data on clay and sand. (2) After the shaking, the factor of safety is modified using a combined empirical and analytical model that links observed earthquake induced changes in rainfall thresholds for triggering of debris flow to an equivalent reduction in soil shear strength. The empirical part uses data from past earthquakes to propose a conceptual model linking a site-specific reduction factor for rainfall intensity threshold (needed to trigger debris flows) to earthquake magnitude, distance from the epicentre and time period after the earthquake. The analytical part is a hydrological model for transient rainfall infiltration into an infinite slope in order to translate the change in rainfall intensity threshold into an equivalent reduction in soil shear strength. This is generalised into a functional form giving a site-specific shear strength reduction factor as function of earthquake history and soil conditions. The model is suitable for hazard and risk

  7. Thin-layer effects in glaciological seismic amplitude-versus-angle (AVA analysis: implications for characterising a subglacial till unit, Russell Glacier, West Greenland

    Directory of Open Access Journals (Sweden)

    A. D. Booth

    2012-08-01

    Full Text Available Seismic amplitude-versus-angle (AVA methods are a powerful means of quantifying the physical properties of subglacial material, but serious interpretative errors can arise when AVA is measured over a thinly-layered substrate. A substrate layer with a thickness less than 1/4 of the seismic wavelength, λ, is considered "thin", and reflections from its bounding interfaces superpose and appear in seismic data as a single reflection event. AVA interpretation of subglacial till can be vulnerable to such thin-layer effects, since a lodged (non-deforming till can be overlain by a thin (metre-scale cap of dilatant (deforming till. We assess the potential for misinterpretation by simulating seismic data for a stratified subglacial till unit, with an upper dilatant layer between 0.1–5.0 m thick (λ / 120 to > λ / 4, with λ = 12 m. For dilatant layers less than λ / 6 thick, conventional AVA analysis yields acoustic impedance and Poisson's ratio that indicate contradictory water saturation. A thin-layer interpretation strategy is proposed, that accurately characterises the model properties of the till unit. The method is applied to example seismic AVA data from Russell Glacier, West Greenland, in which characteristics of thin-layer responses are evident. A subglacial till deposit is interpreted, having lodged till (acoustic impedance = 4.26±0.59 × 106 kg m−2 s−1 underlying a water-saturated dilatant till layer (thickness < 2 m, Poisson's ratio ~ 0.5. Since thin-layer considerations offer a greater degree of complexity in an AVA interpretation, and potentially avoid misinterpretations, they are a valuable aspect of quantitative seismic analysis, particularly for characterising till units.

  8. Korea-Japan Joint Research on Development of Seismic Capacity Evaluation and Enhancement Technology Considering Near-Fault Effect (Final Report)

    Energy Technology Data Exchange (ETDEWEB)

    Choun, Young Sun; Choi, In Kil; Kim, Min Kyu [KAERI, Daejeon (Korea, Republic of); Ohtori, Yasuki; Shiba, Yoshiaki; Nakajima, Masato [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    2006-12-15

    We compiled the results of the source analysis obtained under the collaboration research. Recent construction scheme for source modeling adopted in Japan is described, and strong-motion prediction is performed assuming the scenario earthquakes occurring in the Ulsan fault system, Korea. Finally Qs values beneath the Korean inland crust are estimated using strong-motion records in Korea from the 2005 Off West Fukuoka earthquake (M7.0). Probabilistic seismic hazard for four NPP sites in Korea are evaluated, in which the site specific attenuation equations with Index SA developed for NPP sites are adopted. Furthermore, the uniform hazard spectra for the four NPP sites in Korea are obtained by conducting the PSHA by using the attenuation equations with the index of response spectra and seismic source model cases with maximum weights. The supporting tools for seismic response analysis, the evaluation tool for evaluating annual probability of failure, and system analysis program were developed for the collaboration. The tools were verified with theoretical results, the results written in the reference document of EQESRA, and so forth. The system analysis program was applied for the investigation of the effect of improving the seismic capacity of equipment. We evaluated the annual probability of failure of isolated and non-isolated EDG at Younggwang NPP site as the results of the collaboration. The input ground motion for generating the seismic fragility curve was determined based on the seismic hazard analysis. It was found that the annual probability of failure of isolated EDG is lower than that of non-isolated EDG.

  9. Complex source mechanisms of mining-induced seismic events - implications for surface effects

    Science.gov (United States)

    Orlecka-Sikora, B.; Cesca, S.; Lasocki, S.; Rudzinski, L.; Lizurek, L.; Wiejacz, P.; Urban, P.; kozlowska, M.

    2012-04-01

    The seismicity of Legnica-Głogów Copper District (LGCD) is induced by mining activities in three mines: Lubin, Rudna and Polkowice-Sieroszowice. Ground motion caused by strong tremors might affect local infrastructure. "Żelazny Most" tailings pond, the biggest structure of this type in Europe, is here under special concern. Due to surface objects protection, Rudna Mine has been running ground motion monitoring for several years. From June 2010 to June 2011 unusually strong and extensive surface impact has been observed for 6 mining tremors induced in one of Rudna mining sections. The observed peak ground acceleration (PGA) for both horizontal and vertical component were in or even beyond 99% confidence interval for prediction. The aim of this paper is analyze the reason of such unusual ground motion. On the basis of registrations from Rudna Mine mining seismological network and records from Polish Seismological Network held by the Institute of Geophysics Polish Academy of Sciences (IGF PAN), the source mechanisms of these 6 tremors were calculated using a time domain moment tensor inversion. Furthermore, a kinematic analysis of the seismic source was performed, in order to determine the rupture planes orientations and rupture directions. These results showed that in case of the investigated tremors, point source models and shear fault mechanisms, which are most often assumed in mining seismology, are invalid. All analyzed events indicate extended sources with non-shear mechanism. The rapture planes have small dip angles and the rupture starts at the tremors hypocenter and propagates in the direction opposite to the plane dip. The tensional component plays here also big role. These source mechanisms well explain such observed strong ground motion, and calculated synthetic PGA values well correlates with observed ones. The relationship between mining tremors were also under investigation. All subsequent tremors occurred in the area of increased stress due to

  10. Testing cost-effective methodologies for flood and seismic vulnerability assessment in communities of developing countries (Dajç, northern Albania

    Directory of Open Access Journals (Sweden)

    Veronica Pazzi

    2016-05-01

    Full Text Available Nowadays many developing countries need effective measures to reduce the disaster related risks. Structural interventions are the most effective to achieve these aims. Nevertheless, in the absence of adequate financial resources different low-cost strategies can be used to minimize losses. The purpose of this paper is to demonstrate that the disaster risk reduction can be gathered building a community coping capacity. In the case study, flood and seismic analyses have been carried out using relatively simple and low-cost technologies, fundamental for governments and research institutions of poorly developed countries. In fact, through the acquisition and dissemination of these basic information, a reduction of vulnerability and risk can be achieved. In detail, two methodologies for the evaluation of hydraulic and seismic vulnerability were tested in the Dajç municipality (Northern Albania, a high-seismicity region that is also severely affected by floods. Updated bathymetric, topographic and hydraulic data were processed with HEC-RAS software to identify sites potentially affected by dykes overflowing. Besides, the soil-structure interaction effects for three strategic buildings were studied using microtremors and the Horizontal to Vertical Spectral Ratio method. This flood and seismic vulnerability analysis was then evaluated in terms of costs and ease of accessibility in order to suggest the best use both of the employed devices and the obtained information for designing good civil protection plans and to inform the population about the right behaviour in case of threat.

  11. The effect of regional variation of seismic wave attenuation on the strong ground motion from earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Chung, D H; Bernreuter, D L

    1981-10-01

    Attenuation is caused by geometric spreading and absorption. Geometric spreading is almost independent of crustal geology and physiographic region, but absorption depends strongly on crustal geology and the state of the earth's upper mantle. Except for very high frequency waves, absorption does not affect ground motion at distances less than about 25 to 50 km. Thus, in the near-field zone, the attenuation in the eastern United States is similar to that in the western United States. Beyond the near field, differences in ground motion can best be accounted for by differences in attenuation caused by differences in absorption. The stress drop of eastern earthquakes may be higher than for western earthquakes of the same seismic moment, which would affect the high-frequency spectral content. But we believe this factor is of much less significance than differences in absorption in explaining the differences in ground motion between the East and the West. The characteristics of strong ground motion in the conterminous United States are discussed in light of these considerations, and estimates are made of the epicentral ground motions in the central and eastern United States. (author)

  12. SITE-2, Power Plant Siting, Cost, Environment, Seismic and Meteorological Effects

    International Nuclear Information System (INIS)

    Frigerio, N.A.; Habegger, L.J.; King, R.F.; Hoover, L.J.; Clark, N.A.; Cobian, J.M.

    1977-01-01

    1 - Description of problem or function: SITE2 is designed to (1) screen candidate energy facility sites or areas within an electric utility region, based on the region's physical and socioeconomic attributes, the planned facility's characteristics, and impact assessments, and (2) evaluate the cumulative regional impacts associated with alternate energy supply options and inter-regional energy import/export practices, specifically, comparison of different energy technologies and their regional distribution in clustered or dispersed patterns. 2 - Method of solution: The SITE2 methodology is based on the quantification of three major site-related vectors. A cost vector is determined which identifies site-specific costs, such as transmission costs, cooling costs as related to water availability, and costs of specific controls needed to protect the surrounding environment. An impact vector is also computed for each potential site, using models of health and environmental impacts incurred in areas adjacent to the site. Finally, a site attribute vector is developed which reflects such characteristics as population, seismic conditions, meteorology, land use, and local ecological systems. This vector can be used to eliminate certain sites because of their inability to satisfy specific constraints. These three vectors can be displayed as density maps and combined in a simple overlay approach, similar to that developed by I. L. McHarg in reference 2, to identify candidate sites. Alternatively, the vector elements can be computationally combined into a weighted sum to obtain quantitative indicators of site suitability

  13. SITE-2, Power Plant Siting, Cost, Environment, Seismic and Meteorological Effects

    Energy Technology Data Exchange (ETDEWEB)

    Frigerio, N A [Environmental Impact Studies, Argonne National Laboratory 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Habegger, L J; King, R F; Hoover, L J [Energy and Environmental Systems Division, Argonne National Laboratory 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Clark, N A [Applied Mathematics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Cobian, J M [Northwestern University, Evanston, Illinois 60201 (United States)

    1977-08-01

    1 - Description of problem or function: SITE2 is designed to (1) screen candidate energy facility sites or areas within an electric utility region, based on the region's physical and socioeconomic attributes, the planned facility's characteristics, and impact assessments, and (2) evaluate the cumulative regional impacts associated with alternate energy supply options and inter-regional energy import/export practices, specifically, comparison of different energy technologies and their regional distribution in clustered or dispersed patterns. 2 - Method of solution: The SITE2 methodology is based on the quantification of three major site-related vectors. A cost vector is determined which identifies site-specific costs, such as transmission costs, cooling costs as related to water availability, and costs of specific controls needed to protect the surrounding environment. An impact vector is also computed for each potential site, using models of health and environmental impacts incurred in areas adjacent to the site. Finally, a site attribute vector is developed which reflects such characteristics as population, seismic conditions, meteorology, land use, and local ecological systems. This vector can be used to eliminate certain sites because of their inability to satisfy specific constraints. These three vectors can be displayed as density maps and combined in a simple overlay approach, similar to that developed by I. L. McHarg in reference 2, to identify candidate sites. Alternatively, the vector elements can be computationally combined into a weighted sum to obtain quantitative indicators of site suitability.

  14. Pore-fluid effects on seismic waves in vertically fractured earth with orthotropic symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Berryman, J.G.

    2010-05-15

    For elastically noninteracting vertical-fracture sets at arbitrary orientation angles to each other, a detailed model is presented in which the resulting anisotropic fractured medium generally has orthorhombic symmetry overall. Some of the analysis methods and ideas of Schoenberg are emphasized, together with their connections to other similarly motivated and conceptually related methods by Sayers and Kachanov, among others. Examples show how parallel vertical-fracture sets having HTI (horizontal transversely isotropic) symmetry transform into orthotropic fractured media if some subsets of the vertical fractures are misaligned with the others, and then the fractured system can have VTI (vertical transversely isotropic) symmetry if all of the fractures are aligned randomly or half parallel and half perpendicular to a given vertical plane. An orthotropic example having vertical fractures in an otherwise VTI earth system (studied previously by Schoenberg and Helbig) is compared with the other examples treated and it is finally shown how fluids in the fractures affect the orthotropic poroelastic system response to seismic waves. The key result is that fracture-influence parameters are multiplied by a factor of (1-B), where 0 {le} B < 1 is Skempton's second coefficient for poroelastic media. Skempton's B coefficient is itself a measurable characteristic of fluid-saturated porous rocks, depending on porosity, solid moduli, and the pore-fluid bulk modulus. For heterogeneous porous media, connections between the present work and earlier related results of Brown and Korringa are also established.

  15. Ageing effects due to inactivity for magnetorheological seismic dampers: a 10-year experimental investigation

    Science.gov (United States)

    Caterino, N.; Spizzuoco, M.; Occhiuzzi, A.

    2018-06-01

    The proposed work gives a response, based on the experimental evidence, to the issue of long-term magnetorheological (MR) dampers’ behavior, when they are applied for structural control of earthquake induced vibrations. MR control devices, designed for infrequent dynamic loads as earthquakes, might be dormant for most of their life until a seismic event hits the hosting controlled structure. Two prototype MR devices have been tested three times, first in 2008, then in 2013 after five years of absolute inactivity, and finally in 2017 after further four years of rest. The comparison between the results of the three experimental testing activities is made in terms of force-displacement loops, dissipated energy and maximum reacting force. It is shown that only the first stroke of the damper is characterized by an unexpected mechanical response. However, after this first movement, the damper comes back to behave similarly to what was before the rest, with only a slight not reversible decrease of the damping force. This reduction results to be more significant (about 5%) for larger currents, while less significant in the case of zero feeding current. From a civil engineering perspective, this performance decay is definitely acceptable, even if it is referred to a possible cause, deeply studied in literature, that could continue endangering the mechanical response of the devices over time. The paper shows the experimental results, but the possible causes of mechanical deterioration of the dampers will be discussed also.

  16. Seismic qualification of equipment

    International Nuclear Information System (INIS)

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

    1983-03-01

    This report describes the results of an investigation into the seismic qualification of equipment located in CANDU nuclear power plants. It is particularly concerned with the evaluation of current seismic qualification requirements, the development of a suitable methodology for the seismic qualification of safety systems, and the evaluation of seismic qualification analysis and testing procedures

  17. Causality between expansion of seismic cloud and maximum magnitude of induced seismicity in geothermal field

    Science.gov (United States)

    Mukuhira, Yusuke; Asanuma, Hiroshi; Ito, Takatoshi; Häring, Markus

    2016-04-01

    Occurrence of induced seismicity with large magnitude is critical environmental issues associated with fluid injection for shale gas/oil extraction, waste water disposal, carbon capture and storage, and engineered geothermal systems (EGS). Studies for prediction of the hazardous seismicity and risk assessment of induced seismicity has been activated recently. Many of these studies are based on the seismological statistics and these models use the information of the occurrence time and event magnitude. We have originally developed physics based model named "possible seismic moment model" to evaluate seismic activity and assess seismic moment which can be ready to release. This model is totally based on microseismic information of occurrence time, hypocenter location and magnitude (seismic moment). This model assumes existence of representative parameter having physical meaning that release-able seismic moment per rock volume (seismic moment density) at given field. Seismic moment density is to be estimated from microseismic distribution and their seismic moment. In addition to this, stimulated rock volume is also inferred by progress of microseismic cloud at given time and this quantity can be interpreted as the rock volume which can release seismic energy due to weakening effect of normal stress by injected fluid. Product of these two parameters (equation (1)) provide possible seismic moment which can be released from current stimulated zone as a model output. Difference between output of this model and observed cumulative seismic moment corresponds the seismic moment which will be released in future, based on current stimulation conditions. This value can be translated into possible maximum magnitude of induced seismicity in future. As this way, possible seismic moment can be used to have feedback to hydraulic stimulation operation in real time as an index which can be interpreted easily and intuitively. Possible seismic moment is defined as equation (1), where D

  18. Seismic Safety Guide

    International Nuclear Information System (INIS)

    Eagling, D.G.

    1985-01-01

    The Seismic Safety Guide provides facilities managers with practical guidelines for administering a comprehensive earthquake safety program. Most facilities managers, unfamiliar with earthquake engineering, tend to look for answers in techniques more sophisticated than required to solve the actual problems in earthquake safety. Often the approach to solutions to these problems is so academic, legalistic, and financially overwhelming that mitigation of actual seismic hazards simply does not get done in a timely, cost-effective way. The objective of the Guide is to provide practical advice about earthquake safety so that managers and engineers can get the job done without falling into common pitfalls, prolonged diagnosis, and unnecessary costs. It is comprehensive with respect to earthquakes in that it covers the most important aspects of natural hazards, site planning, rehabilitation of existing buildings, design of new facilities, operational safety, emergency planning, non-structural elements, life lines, and risk management. 5 references

  19. German seismic regulations

    International Nuclear Information System (INIS)

    Danisch, Ruediger

    2002-01-01

    Rules and regulations for seismic design in Germany cover the following: seismic design of conventional buildings; and seismic design of nuclear facilities. Safety criteria for NPPs, accident guidelines, and guidelines for PWRs as well as safety standards are cited. Safety standards concerned with NPPs seismic design include basic principles, soil analysis, design of building structures, design of mechanical and electrical components, seismic instrumentation, and measures to be undertaken after the earthquake

  20. Seismic Isolation Working Meeting Gap Analysis Report

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-09-01

    The ultimate goal in nuclear facility and nuclear power plant operations is operating safety during normal operations and maintaining core cooling capabilities during off-normal events including external hazards. Understanding the impact external hazards, such as flooding and earthquakes, have on nuclear facilities and NPPs is critical to deciding how to manage these hazards to expectable levels of risk. From a seismic risk perspective the goal is to manage seismic risk. Seismic risk is determined by convolving the seismic hazard with seismic fragilities (capacity of systems, structures, and components (SSCs)). There are large uncertainties associated with evolving nature of the seismic hazard curves. Additionally there are requirements within DOE and potential requirements within NRC to reconsider updated seismic hazard curves every 10 years. Therefore opportunity exists for engineered solutions to manage this seismic uncertainty. One engineered solution is seismic isolation. Current seismic isolation (SI) designs (used in commercial industry) reduce horizontal earthquake loads and protect critical infrastructure from the potentially destructive effects of large earthquakes. The benefit of SI application in the nuclear industry is being recognized and SI systems have been proposed, in the American Society of Civil Engineers (ASCE) 4 standard, to be released in 2014, for Light Water Reactors (LWR) facilities using commercially available technology. However, there is a lack of industry application to the nuclear industry and uncertainty with implementing the procedures outlined in ASCE-4. Opportunity exists to determine barriers associated with implementation of current ASCE-4 standard language.

  1. Recent Vs. Historical Seismicity Analysis For Banat Seismic Region (Western Part Of Romania

    Directory of Open Access Journals (Sweden)

    Oros Eugen

    2015-03-01

    Full Text Available The present day seismic activity from a region reflects the active tectonics and can confirm the seismic potential of the seismogenic sources as they are modelled using the historical seismicity. This paper makes a comparative analysis of the last decade seismicity recorded in the Banat Seismic Region (western part of Romania and the historical seismicity of the region (Mw≥4.0. Four significant earthquake sequences have been recently localized in the region, three of them nearby the city of Timisoara (January 2012 and March 2013 and the fourth within Hateg Basin, South Carpathians (October 2013. These sequences occurred within the epicentral areas of some strong historical earthquakes (Mw≥5.0. The main events had some macroseismic effects on people up to some few kilometers from the epicenters. Our results update the Romanian earthquakes catalogue and bring new information along the local seismic hazard sources models and seismotectonics.

  2. Korea-Japan Joint Research on Development of Seismic Capacity Evaluation and Enhancement Technology Considering Near-Fault Effect

    Energy Technology Data Exchange (ETDEWEB)

    Choun, Young Sun; Choi, In Kil; Kim, Min Kyu [KAERI, Daejon (Korea, Republic of); Ohtori, Yasuki; Shiba, Yoshiaki; Nakajima, Masato [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    2005-12-15

    Several recent improved methods for the EGFM are introduced in order to avoid artificial holes seen in the synthetic acceleration spectrum. Furthermore evaluation of input ground motions at Wolsung NPP are performed by varying the source parameters that may control the high-frequency wave radiation and the deviation of the synthetic motions are revealed. The PSHA case studies for four NPP sites (Wolsung, Kori, Uljin, Younggwang) are performed. In the analysis, site-specific attenuation equations developed for Korean NPP sites are employed, and the seismic hazards for the target sites are evaluated in the case where the four kind of seismic source models are considered. Moreover, the PSHA for Wolsung and Younggwang are conducted by using the site-specific attenuation equation with the index of response spectra and the uniform hazard spectra are evaluated for the two sites. The supporting tool for seismic response analysis and the evaluation tool for evaluating annual probability of failure were integrated in the frame of the seismic risk assessment system. Then, the tools were applied to the seismic risk assessment of the conventional EDG and isolated EDG. General information such as earthquake parameters and regional distribution of seismic intensity is summarized on the 2005 West Off Fukuoka earthquake. Then, the observed strong motion records in Japan and Korea sites are compiled, and regional distribution of peak accelerations are represented. Moreover, the peak accelerations of the records are compared with the values estimated from the existing attenuation equations.

  3. An investigation on the effect of gusset plate connection rigidity on the seismic behavior of special concentrically braced frames

    Directory of Open Access Journals (Sweden)

    Ali Esnaashari

    2016-12-01

    Full Text Available Special concentrically braced frames (SCBFs are commonly used to resist lateral loads in buildings. The bracing system sustains large deformations due to inelastic behavior in bracing members (buckling and yielding in tension. Generally, in the conventional modeling strategy, the effect of gusset plates in providing beam-column connections rigidity and hence, improving the post-buckling performance of these frames is not taken into account. This paper deals with the effect of gusset plate rigidity on the seismic behavior of SCBFs using Roeder’s proposed model in the literature. In this paper, four 3, 6, 9 and 12-story SCBFs were designed and modeled using two distinct methods: conventional method with hinged connections and Roeder’s method with semi-rigid connections. Then, the models behavior was investigated with both pushover analysis and nonlinear time-history analysis using OpenSees software. The results showed that lateral load capacity of the frames modeled with the Roeder’s proposed model are about 10% larger than the conventional method’s capacity. Also, it was found that the semi-rigid model leads to a less drift ratios and more overstrength factors.

  4. Investigation of the effects of a seismic event on accelerated aged components and benefits in equipment life extension

    International Nuclear Information System (INIS)

    Rygg, D.E.; Epstein, J.L.

    1985-01-01

    Westinghouse has performed extensive testing to determine the effects of aging on a wide range of components. Additionally, Westinghouse has an extensive data base of nuclear plant equipment and components. This paper presents how the data base of information on plant parts can be analyzed, modified, and managed or tracked to reflect in-plant parts life extension based on actual tests on aging. Such an approach can benefit utility programs for parts inventory, plant operations and plant availability, and can also reduce the costs of parts reordering. Rather than weigh the merits of the positions in this debate, this paper presents the results of a component aging program which simulates from five to twenty years of operation followed by a seismic event and identifies the possible incorporation of this data into a plant data base which offers quick reference and provides other relevant information on the component and equipment. The use of this data as part of a well structured maintenance and surveillance program offers an avenue to resolve this debate in a cost effective manner

  5. Effect of the flexibility of the base mat on seismic response of a PWR-reactor building

    International Nuclear Information System (INIS)

    Waas, G.; Riggs, H.R.

    1983-01-01

    The flexibility of the base mat influences the stiffness and the radiation damping of foundations, In this paper its effect on the seismic response of an axisymmetric PWR-reactor building is investigated. The base mat of the building is stiffened by cylindrical concrete walls and by a rigid block in the center. Soft and stiff soil conditions are considered. The structure and its foundation are modelled by axisymmetric shell and volume elements with Fourier expansions in the circumferential direction. The soil is treated as a horizontally layered viscoelastic medium. Soil and structure are coupled along nodal rings. The stiffness matrix of the soil is computed using an explicit semi-analytic solution for displacements caused by ring loads acting on the surface or within a layered medium. The analysis is performed in the frequency domain, and the response in the time domain is computed by the fast Fourier transformation. The earthquake response is computed with and without including the flexibility of the relatively stiff base mat. The comparison shows that including the flexibility of the mat has hardly any effect on the resonant frequencies and the damping of the fundamental rocking and vertical modes. This is the case for soft and stiff soil conditions. However, the flexibility of the mat strongly affects the first structural deformation mode, in which the external and internal structures deflect in opposite directions. (orig./HP)

  6. 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)

  7. Romanian Educational Seismic Network Project

    Science.gov (United States)

    Tataru, Dragos; Ionescu, Constantin; Zaharia, Bogdan; Grecu, Bogdan; Tibu, Speranta; Popa, Mihaela; Borleanu, Felix; Toma, Dragos; Brisan, Nicoleta; Georgescu, Emil-Sever; Dobre, Daniela; Dragomir, Claudiu-Sorin

    2013-04-01

    Romania is one of the most active seismic countries in Europe, with more than 500 earthquakes occurring every year. The seismic hazard of Romania is relatively high and thus understanding the earthquake phenomena and their effects at the earth surface represents an important step toward the education of population in earthquake affected regions of the country and aims to raise the awareness about the earthquake risk and possible mitigation actions. In this direction, the first national educational project in the field of seismology has recently started in Romania: the ROmanian EDUcational SEISmic NETwork (ROEDUSEIS-NET) project. It involves four partners: the National Institute for Earth Physics as coordinator, the National Institute for Research and Development in Construction, Urban Planning and Sustainable Spatial Development " URBAN - INCERC" Bucharest, the Babeş-Bolyai University (Faculty of Environmental Sciences and Engineering) and the software firm "BETA Software". The project has many educational, scientific and social goals. The main educational objectives are: training students and teachers in the analysis and interpretation of seismological data, preparing of several comprehensive educational materials, designing and testing didactic activities using informatics and web-oriented tools. The scientific objective is to introduce into schools the use of advanced instruments and experimental methods that are usually restricted to research laboratories, with the main product being the creation of an earthquake waveform archive. Thus a large amount of such data will be used by students and teachers for educational purposes. For the social objectives, the project represents an effective instrument for informing and creating an awareness of the seismic risk, for experimentation into the efficacy of scientific communication, and for an increase in the direct involvement of schools and the general public. A network of nine seismic stations with SEP seismometers

  8. The effects of thick sediment upon continental breakup: seismic imaging and thermal modeling of the Salton Trough, southern California

    Science.gov (United States)

    Han, L.; Hole, J. A.; Lowell, R. P.; Stock, J. M.; Fuis, G. S.; Driscoll, N. W.; Kell, A. M.; Kent, G. M.; Harding, A. J.; Gonzalez-Fernandez, A.; Lázaro-Mancilla, O.

    2015-12-01

    Continental rifting ultimately creates a deep accommodation space for sediment. When a major river flows into a late-stage rift, thick deltaic sediment can change the thermal regime and alter the mechanisms of extension and continental breakup. The Salton Trough, the northernmost rift segment of the Gulf of California plate boundary, has experienced the same extension as the rest of the Gulf, but is filled to sea level by sediment from the Colorado River. Unlike the southern Gulf, seafloor spreading has not initiated. Instead, seismicity, high heat flow, and minor volcanoes attest to ongoing rifting of thin, transitional crust. Recently acquired controlled-source seismic refraction and wide-angle reflection data in the Salton Trough provide constraints upon crustal architecture and active rift processes. The crust in the central Salton Trough is only 17-18 km thick, with a strongly layered but relatively one-dimensional structure for ~100 km in the direction of plate motion. The upper crust includes 2-4 km of Colorado River sediment. Crystalline rock below the sediment is interpreted to be similar sediment metamorphosed by the high heat flow and geothermal activity. Meta-sediment extends to at least 9 km depth. A 4-5 km thick layer in the middle crust is either additional meta-sediment or stretched pre-existing continental crust. The lowermost 4-5 km of the crust is rift-related mafic magmatic intrusion or underplating from partial melting in the hot upper mantle. North American lithosphere in the Salton Trough has been almost or completely rifted apart. The gap has been filled by ~100 km of new transitional crust created by magmatism from below and sedimentation from above. These processes create strong lithologic, thermal, and rheologic layering. While heat flow in the rift is very high, rapid sedimentation cools the upper crust as compared to a linear geotherm. Brittle extension occurs within new meta-sedimentary rock. The lower crust, in comparison, is

  9. Co-Seismic Effect of the 2011 Japan Earthquake on the Crustal Movement Observation Network of China

    Directory of Open Access Journals (Sweden)

    Shaomin Yang

    2013-01-01

    Full Text Available Great earthquakes introduce measurable co-seismic displacements over regions of hundreds and thousands of kilometers in width, which, if not accounted for, may significantly bias the long-term surface velocity field constrained by GPS observations performed during a period encompassing that event. Here, we first present an estimation of the far-field co-seismic off-sets associated with the 2011 Japan Mw 9.0 earthquake using GPS measurements from the Crustal Movement Observation Network of China (CMONOC in North China. The uncertainties of co-seismic off-set, either at cGPS stations or at campaign sites, are better than 5 - 6 mm on average. We compare three methods to constrain the co-seismic off-sets at the campaign sites in northeastern China 1 interpolating cGPS coseismic offsets, 2 estimating in terms of sparsely sampled time-series, and 3 predicting by using a well-constrained slip model. We show that the interpolation of cGPS co-seismic off-sets onto the campaign sites yield the best co-seismic off-set solution for these sites. The source model gives a consistent prediction based on finite dislocation in a layered spherical Earth, which agrees with the best prediction with discrepancies of 2 - 10 mm for 32 campaign sites. Thus, the co-seismic off-set model prediction is still a reasonable choice if a good coverage cGPS network is not available for a very active region like the Tibetan Plateau in which numerous campaign GPS sites were displaced by the recent large earthquakes.

  10. Use of the SSHAC methodology within regulated environments: Cost-effective application for seismic characterization at multiple sites

    International Nuclear Information System (INIS)

    Coppersmith, Kevin J.; Bommer, Julian J.

    2012-01-01

    Highlights: ► SSHAC processes provide high levels of regulatory assurance in hazard assessments for purposes of licensing and safety review. ► SSHAC projects provide structure to the evaluation of available data, models, and methods for building hazard input models. ► Experience on several nuclear projects in the past 15 years leads to the identification of key essential procedural steps. ► Conducting a regional SSHAC Level 3 study, followed by Level 2 site-specific studies can be time and cost effective. - Abstract: Essential elements of license applications and safety reviews for nuclear facilities are quantifications of earthquake and other natural hazards. A Senior Seismic Hazard Analysis Committee (SSHAC) Level 3 or 4 process provides regulatory assurance that the hazard assessment considers all data and models proposed by members of the technical community and the associated uncertainties have been properly quantified. The SSHAC process has been endorsed as an acceptable hazard assessment methodology in US NRC regulatory guidance. Where hazard studies are required for multiple sites, regional SSHAC Level 3 or 4 studies followed by site-specific Level 2 refinements can provide major benefits in cost and duration.

  11. The Effects of Fracture Anisotropy on the Damage Pattern and Seismic Radiation from a Chemical Explosion in a Granite Quarry

    Science.gov (United States)

    Rogers-Martinez, M. A.; Sammis, C. G.; Ezzedine, S. M.

    2017-12-01

    As part of the New England Damage Experiment (NEDE) a 122.7 kg Heavy ANFO charge was detonated at a depth of 13 m in a granite quarry in Barre Vt. Subsequent drill cores from the source region revealed that most of the resultant fracturing was concentrated in the rift plane of the highly anisotropic Barre granite. We simulated this explosion using a dynamic damage mechanics model embedded in the ABAQUS 3D finite element code. The damage mechanics was made anisotropic by taking the critical stress intensity factor to be a function of azimuth in concert with the physics of interacting parallel fractures and laboratory studies of anisotropic granite. In order to identify the effects of anisotropy, the explosion was also simulated assuming 1) no initial damage (pure elasticity) and 2) isotropic initial damage. For the anisotropic case, the calculated fracture pattern simulated that observed in NEDE. The simulated seismic radiation looked very much like that from a tensile fracture oriented in the rift plane, and similar to the crack-like moment tensor observed in the far field of many nuclear explosions.

  12. Experimental and numerical investigations of higher mode effects on seismic inelastic response of reinforced concrete shear walls

    Science.gov (United States)

    Ghorbanirenani, Iman

    This thesis presents two experimental programs together with companion numerical studies that were carried out on reinforced concrete shear walls: static tests and dynamic (shake table) tests. The first series of experiments were monotonic and cyclic quasi-static testing on ductile reinforced concrete shear wall specimens designed and detailed according to the seismic provisions of NBCC 2005 and CSA-A23.3-04 standard. The tests were carried out on full-scale and 1:2.37 reduced scale wall specimens to evaluate the seismic design provisions and similitude law and determine the appropriate scaling factor that could be applied for further studies such as dynamic tests. The second series of experiments were shake table tests conducted on two identical 1:2.33 scaled, 8-storey moderately ductile reinforced concrete shear wall specimens to investigate the effects of higher modes on the inelastic response of slender walls under high frequency ground motions expected in Eastern North America. The walls were designed and detailed according to the seismic provisions of NBCC 2005 and CSA-A23.3-04 standard. The objectives were to validate and understand the inelastic response and interaction of shear, flexure and axial loads in plastic hinge zones of the walls considering the higher mode effects and to investigate the formation of second hinge in upper part of the wall due to higher mode responses. Second mode response significantly affected the response of the walls. This caused inelastic flexural response to develop at the 6th level with approximately the same rotation ductility compared to that observed at the base. Dynamic amplification of the base shear forces was also observed in both walls. Numerical modeling of these two shake table tests was performed to evaluate the test results and validate current modeling approaches. Nonlinear time history analyses were carried out by the reinforced concrete fibre element (OpenSees program) and finite element (VecTor2 program

  13. Experimental measurement at the seismic station Ostrava-Krásné Pole (OKC): preliminary results and remarks on site effect at the studied locality

    Czech Academy of Sciences Publication Activity Database

    Lednická, Markéta; Rušajová, Jana

    2016-01-01

    Roč. 13, č. 2 (2016), s. 137-147 ISSN 1214-9705 R&D Projects: GA MŠk LM2010008; GA ČR GP13-07027P Institutional support: RVO:68145535 Keywords : seismic station OKC * spectral ratio * site effect Subject RIV: JM - Building Engineering Impact factor: 0.699, year: 2016 https://www.irsm.cas.cz/index.php?page=acta_content_doi&id_cislo=17

  14. Seismic Imager Space Telescope

    Science.gov (United States)

    Sidick, Erkin; Coste, Keith; Cunningham, J.; Sievers,Michael W.; Agnes, Gregory S.; Polanco, Otto R.; Green, Joseph J.; Cameron, Bruce A.; Redding, David C.; Avouac, Jean Philippe; hide

    2012-01-01

    A concept has been developed for a geostationary seismic imager (GSI), a space telescope in geostationary orbit above the Pacific coast of the Americas that would provide movies of many large earthquakes occurring in the area from Southern Chile to Southern Alaska. The GSI movies would cover a field of view as long as 300 km, at a spatial resolution of 3 to 15 m and a temporal resolution of 1 to 2 Hz, which is sufficient for accurate measurement of surface displacements and photometric changes induced by seismic waves. Computer processing of the movie images would exploit these dynamic changes to accurately measure the rapidly evolving surface waves and surface ruptures as they happen. These measurements would provide key information to advance the understanding of the mechanisms governing earthquake ruptures, and the propagation and arrest of damaging seismic waves. GSI operational strategy is to react to earthquakes detected by ground seismometers, slewing the satellite to point at the epicenters of earthquakes above a certain magnitude. Some of these earthquakes will be foreshocks of larger earthquakes; these will be observed, as the spacecraft would have been pointed in the right direction. This strategy was tested against the historical record for the Pacific coast of the Americas, from 1973 until the present. Based on the seismicity recorded during this time period, a GSI mission with a lifetime of 10 years could have been in position to observe at least 13 (22 on average) earthquakes of magnitude larger than 6, and at least one (2 on average) earthquake of magnitude larger than 7. A GSI would provide data unprecedented in its extent and temporal and spatial resolution. It would provide this data for some of the world's most seismically active regions, and do so better and at a lower cost than could be done with ground-based instrumentation. A GSI would revolutionize the understanding of earthquake dynamics, perhaps leading ultimately to effective warning

  15. Permanent downhole seismic sensors in flowing wells

    NARCIS (Netherlands)

    Jaques, P.; Ong, H.; Jupe, A.; Brown, I.; Jansenns, M.

    2003-01-01

    It is generally accepted that the 'Oilfield of the Future' will incorporate distributed permanent downhole seismic sensors in flowing wells. However the effectiveness of these sensors will be limited by the extent to which seismic signals can be discriminated, or de-coupled, from flow induced

  16. Seismic intrusion detector system

    Science.gov (United States)

    Hawk, Hervey L.; Hawley, James G.; Portlock, John M.; Scheibner, James E.

    1976-01-01

    A system for monitoring man-associated seismic movements within a control area including a geophone for generating an electrical signal in response to seismic movement, a bandpass amplifier and threshold detector for eliminating unwanted signals, pulse counting system for counting and storing the number of seismic movements within the area, and a monitoring system operable on command having a variable frequency oscillator generating an audio frequency signal proportional to the number of said seismic movements.

  17. National Seismic Station

    International Nuclear Information System (INIS)

    Stokes, P.A.

    1982-06-01

    The National Seismic Station was developed to meet the needs of regional or worldwide seismic monitoring of underground nuclear explosions to verify compliance with a nuclear test ban treaty. The Station acquires broadband seismic data and transmits it via satellite to a data center. It is capable of unattended operation for periods of at least a year, and will detect any tampering that could result in the transmission of unauthentic seismic data

  18. Study on dynamic buckling behavior of a cylindrical liquid storage tanks under seismic excitation. 1st report, effects of liquid pressure on elephant foot bulge

    International Nuclear Information System (INIS)

    Ito, Tomohiro; Morita, Hideyuki; Sugiyama, Akihisa; Kawamoto, Yoji; Sirai, Eiji; Ogo, Hideyasu

    2004-01-01

    When a thin walled cylindrical liquid storage tank is exposed to a very large seismic base excitation, buckling phenomena may be caused such as bending buckling where diamond buckling pattern or elephant foot bulge pattern will be found at the bottom portion, and shear buckling at the middle portion of the tank. In this study, dynamic buckling tests were performed using scale models of thin cylindrical liquid storage tanks for the nuclear power plants. The input seismic acceleration was increased until the elephant foot bulge occurred and the vibrational behavior before and after buckling was investigated. And the effects of static and dynamic liquid pressure on the bending buckling patterns and the buckling critical force was investigated by fundamental tests using small tank models. (author)

  19. Project investigation and analysis of soil-structure interaction effects in seismic response of NPPs EBO, EMO, Slovakia. Final report

    International Nuclear Information System (INIS)

    Juhasova, E.

    1999-01-01

    The work described in this report was devoted to investigation of expected seismic response of the structures of WWER-440/213 type NPPs, namely Mochovce and Bohunice. Special attention was devoted to the properties of subsoil materials and the transfer of seismic waves from the bedrock to the foundation structures. Theoretical background was elaborated and discussed for wave propagation of surface waves. Alternative procedure was derived for non-linear media accounting for complex modulus theory. Material characteristics of subsoils were investigated for both NPPs. The obtained results were used as a basis for forecasting and calculation of expected seismic response when the time history records from Paks explosion were used an input. It was pointed out that the used procedure, together with previous calculation of subsoil transfer characteristics completed well the comparison with experimental results

  20. Quantitative Seismic Amplitude Analysis

    NARCIS (Netherlands)

    Dey, A.K.

    2011-01-01

    The Seismic Value Chain quantifies the cyclic interaction between seismic acquisition, imaging and reservoir characterization. Modern seismic innovation to address the global imbalance in hydrocarbon supply and demand requires such cyclic interaction of both feed-forward and feed-back processes.

  1. Potential Geophysical Field Transformations and Combined 3D Modelling for Estimation the Seismic Site Effects on Example of Israel

    Science.gov (United States)

    Eppelbaum, Lev; Meirova, Tatiana

    2015-04-01

    It is well-known that the local seismic site effects may have a significant contribution to the intensity of damage and destruction (e.g., Hough et al., 1990; Regnier et al., 2000; Bonnefoy-Claudet et al., 2006; Haase et al., 2010). The thicknesses of sediments, which play a large role in amplification, usually are derived from seismic velocities. At the same time, thickness of sediments may be determined (or defined) on the basis of 3D combined gravity-magnetic modeling joined with available geological materials, seismic data and borehole section examination. Final result of such investigation is a 3D physical-geological model (PGM) reflecting main geological peculiarities of the area under study. Such a combined study needs in application of a reliable 3D mathematical algorithm of computation together with advanced methodology of 3D modeling. For this analysis the developed GSFC software was selected. The GSFC (Geological Space Field Calculation) program was developed for solving a direct 3-D gravity and magnetic prospecting problem under complex geological conditions (Khesin et al., 1996; Eppelbaum and Khesin, 2004). This program has been designed for computing the field of Δg (Bouguer, free-air or observed value anomalies), ΔZ, ΔX, ΔY , ΔT , as well as second derivatives of the gravitational potential under conditions of rugged relief and inclined magnetization. The geological space can be approximated by (1) three-dimensional, (2) semi-infinite bodies and (3) those infinite along the strike closed, L.H. non-closed, R.H. on-closed and open). Geological bodies are approximated by horizontal polygonal prisms. The program has the following main advantages (besides abovementioned ones): (1) Simultaneous computing of gravity and magnetic fields; (2) Description of the terrain relief by irregularly placed characteristic points; (3) Computation of the effect of the earth-air boundary by the method of selection directly in the process of interpretation; (4

  2. Seismic Analysis of Intake Towers Considering Multiple-Support Excitation and Soil-Structure Interaction Effects

    National Research Council Canada - National Science Library

    Vidot, Aidcer

    2004-01-01

    .... The other effect examined is the soil-structure interaction. First, a direct approach based on a finite element model of the tower, bridge, and dam with the earthquake motion applied at the bedrock is used...

  3. Experimental and analytical study on vibration control effects of eddy-current tuned mass dampers under seismic excitations

    Science.gov (United States)

    Lu, Zheng; Huang, Biao; Zhang, Qi; Lu, Xilin

    2018-05-01

    Eddy-current tuned mass dampers (EC-TMDs) are non-contacting passive control devices and are developed on the basis of conventional tuned mass dampers. They comprise a solid mass, a stiffness element, and a damping element, wherein the damping mechanism originates from eddy currents. By relative motion between a non-magnetic conductive metal and a permanent magnet in a dynamic system, a time-varying magnetic field is induced in the conductor, thereby generating eddy currents. The eddy currents induce a magnetic field with opposite polarity, causing repulsive forces, i.e., damping forces. This technology can overcome the drawbacks of conventional tuned mass dampers, such as limited service life, deterioration of mechanical properties, and undesired additional stiffness. The experimental and analytical study of this system installed on a multi-degree-of-freedom structure is presented in this paper. A series of shaking table tests were conducted on a five-story steel-frame model with/without an EC-TMD to evaluate the effectiveness and performance of the EC-TMD in suppressing the vibration of the model under seismic excitations. The experimental results show that the EC-TMD can effectively reduce the displacement response, acceleration response, interstory drift ratio, and maximum strain of the columns under different earthquake excitations. Moreover, an analytical method was proposed on the basis of electromagnetic and structural dynamic theories. A comparison between the test and simulation results shows that the simulation method can be used to estimate the response of structures with an EC-TMD under earthquake excitations with acceptable accuracy.

  4. 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

  5. Seismic induced earth pressures in buried vaults

    International Nuclear Information System (INIS)

    Miller, C.A.; Costantino, C.J.

    1994-01-01

    The magnitude and distribution of earth pressures acting on buried structures and induced by a seismic event are considered in this paper. A soil-structure-interaction analysis is performed for typical Department of Energy high level waste storage tanks using a lumped parameter model. The resulting soil pressure distributions are determined and compared with the static soil pressure to assess the design significance of the seismic induced soil pressures. It is found that seismic pressures do not control design unless the peak ground acceleration exceeds about 0.3 G. The effect of soil non linearities (resulting from local soil failure) are also found to have little effect on the predictions of the seismic response of the buried structure. The seismic induced pressures are found to be very similar to those predicted using the elastic model in ASCE 4-86

  6. Seismic response of uplifting concrete gravity dams

    International Nuclear Information System (INIS)

    Leger, P.; Sauve, G.; Bhattacharjee, S.

    1992-01-01

    The foundation interaction effects on the seismic response of dam-foundation systems have generally been studied using the linear elastic finite element models. In reality, the foundation can not develop effective tensile stresses to a significant degree along the interface. A two-dimensional finite element model, in which nonlinear gap elements are used at the dam-foundation interface to determine the uplift response of concrete gravity dams subjected to seismic loads, is presented. Time domain analyses were performed for a wide range of modelling assumptions such as dam height, interface uplift pressure, interface mesh density, and earthquake input motions, that were systematically varied to find their influence on the seismic response. The nonlinear interface behavior generally reduces the seismic response of dam-foundation systems acting as a seismic isolation mechanism, and may increase the safety against sliding by reducing the base shear transmitted to the foundation. 4 refs., 5 figs., 6 tabs

  7. Compositional trends among Kaapvaal Craton garnet peridotite xenoliths and their effects on seismic velocity and density

    DEFF Research Database (Denmark)

    Schutt, Derek; Lesher, Charles

    2010-01-01

    and clinopyroxene enrichment possibly as a consequence of melt infiltration. More than half of the mineral mode variance among Kaapvaal Craton xenoliths can be accounted for by opx enrichment. Melt depletion effects can account for as much as 30% of the variance, while less than 20% of the variance is associated...

  8. France's seismic zoning

    International Nuclear Information System (INIS)

    Mohammadioun, B.

    1997-01-01

    In order to assess the seismic hazard in France in relation to nuclear plant siting, the CEA, EDF and the BRGM (Mine and Geology Bureau) have carried out a collaboration which resulted in a seismic-tectonic map of France and a data base on seismic history (SIRENE). These studies were completed with a seismic-tectonic zoning, taking into account a very long period of time, that enabled a probabilistic evaluation of the seismic hazard in France, and that may be related to adjacent country hazard maps

  9. The effect of seismic energy scavenging on host structure and harvesting performance

    International Nuclear Information System (INIS)

    Lallart, Mickaël; Wu, Yi-Chieh; Yan, Linjuan; Richard, Claude; Guyomar, Daniel

    2013-01-01

    Cantilevered piezoelectric energy harvesters have been studied extensively in recent years. Numerous techniques have been investigated to achieve optimal power output. However, the extraction of electrical energy from mechanical vibration leads to a reduction of the vibration magnitude of the harvester because of the electromechanical coupling effect, and so a model considering constant vibration magnitude input is no longer valid. Thus, an energy harvesting model excited with a constant force or acceleration magnitude has been adopted to take into account the damping effect induced by the energy harvesting process. This paper extends this model to the effect of energy harvesting on the fixed host structure (mechanical to mechanical coupling). Theoretical developments are presented as a dynamic problem of an electromechanically coupled two-degree-of-freedom (TDOF) spring–mass–damper system. Then, experimental measurements and computations based on finite element modeling (FEM) are carried out to validate theoretical predictions. It is shown that the extracted power obtained from the TDOF model would reach a maximal value by tuning the mass ratio between the host structure and the harvester and optimizing the electric load. The mechanical to mechanical coupling effect due to the harvester leads to a trade-off between the mechanical energy of the host structure and the harvested energy. When the harvester mass to host structure mass ratio is around 10 −3 , the maximal power is obtained and the host structure then has a sudden displacement reduction due to the strong mechanical to mechanical coupling. Experimental measurements have been performed for a mass ratio of around 0.02, with which the harvester effect is not negligible on the host structure behavior as the host structure displacement shows a decrease of more than 3 dB. In addition, the harvested power calculated with the TDOF model is about two times less than with a single-degree-of-freedom (SDOF

  10. Effect on non-linear soil-structure interaction due to base slab uplift on the seismic response of a high-temperature gas-cooled reactor (HTGR)

    International Nuclear Information System (INIS)

    Kennedy, R.P.; Short, S.A.

    1976-01-01

    In high seismic regions it has often been the practice to use oversized base slabs for the major nuclear power plant structures in order to prevent, or at least minimize the amount of dynamic base slab uplift which will result from the overturning moments developed during seismic ground motion. Two major reasons have been expressed as to why dynamic base slab uplift should be minimized: (1) As nuclear power plants are normally designed for seismic loadings based upon linear analysis, and since soil-structure interaction becomes nonlinear when only a portion of the base slab is in contact with the soil, linear elasticity analysis may be acceptable if base slab uplift occurs (as the resultant design loads may be incorrect), and (2) substantial uplift could cause excessive toe pressures in the supporting soil and significant impact forces when the slab recontacts the soil. The primary purpose of this paper is to evaluate the importance of the nonlinear soil-structure interaction effects resulting from substantial base slab uplift occurring during a seismic excitation. The structure for this investigation consisted of the containment building and prestressed reactor vessel (PCRV) for a typical HTGR plant. A simplified dynamic mathematical model was utilized consisting of a conventional lumped mass structure with soil-structure interaction accounted for by translational and rotational springs whose properties are determined by elastic half space theory. Three different site soil conditions (a rock site, a moderately stiff soil, and a soft soil) and two levels of horizontal ground motion (0.3 and 0.5 g earthquakes) were considered. (Auth.)

  11. Toward understanding subtle instrumentation effects associated with weak seismic events in the near field

    Czech Academy of Sciences Publication Activity Database

    Zahradník, J.; Plešinger, Axel

    2010-01-01

    Roč. 100, č. 1 (2010), s. 59-73 ISSN 0037-1106 R&D Projects: GA AV ČR IAA300120911 Grant - others:GA ČR(CZ) GA205/07/0502 Institutional research plan: CEZ:AV0Z30120515 Keywords : instrumentation effects * broadband seismology * weak earthquakes Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.027, year: 2010

  12. Seismic risk perception test

    Science.gov (United States)

    Crescimbene, Massimo; La Longa, Federica; Camassi, Romano; Pino, Nicola Alessandro

    2013-04-01

    The perception of risks involves the process of collecting, selecting and interpreting signals about uncertain impacts of events, activities or technologies. In the natural sciences the term risk seems to be clearly defined, it means the probability distribution of adverse effects, but the everyday use of risk has different connotations (Renn, 2008). The two terms, hazards and risks, are often used interchangeably by the public. Knowledge, experience, values, attitudes and feelings all influence the thinking and judgement of people about the seriousness and acceptability of risks. Within the social sciences however the terminology of 'risk perception' has become the conventional standard (Slovic, 1987). The mental models and other psychological mechanisms which people use to judge risks (such as cognitive heuristics and risk images) are internalized through social and cultural learning and constantly moderated (reinforced, modified, amplified or attenuated) by media reports, peer influences and other communication processes (Morgan et al., 2001). Yet, a theory of risk perception that offers an integrative, as well as empirically valid, approach to understanding and explaining risk perception is still missing". To understand the perception of risk is necessary to consider several areas: social, psychological, cultural, and their interactions. Among the various research in an international context on the perception of natural hazards, it seemed promising the approach with the method of semantic differential (Osgood, C.E., Suci, G., & Tannenbaum, P. 1957, The measurement of meaning. Urbana, IL: University of Illinois Press). The test on seismic risk perception has been constructed by the method of the semantic differential. To compare opposite adjectives or terms has been used a Likert's scale to seven point. The test consists of an informative part and six sections respectively dedicated to: hazard; vulnerability (home and workplace); exposed value (with reference to

  13. Seismic source characterization for the 2014 update of the U.S. National Seismic Hazard Model

    Science.gov (United States)

    Moschetti, Morgan P.; Powers, Peter; Petersen, Mark D.; Boyd, Oliver; Chen, Rui; Field, Edward H.; Frankel, Arthur; Haller, Kathleen; Harmsen, Stephen; Mueller, Charles S.; Wheeler, Russell; Zeng, Yuehua

    2015-01-01

    We present the updated seismic source characterization (SSC) for the 2014 update of the National Seismic Hazard Model (NSHM) for the conterminous United States. Construction of the seismic source models employs the methodology that was developed for the 1996 NSHM but includes new and updated data, data types, source models, and source parameters that reflect the current state of knowledge of earthquake occurrence and state of practice for seismic hazard analyses. We review the SSC parameterization and describe the methods used to estimate earthquake rates, magnitudes, locations, and geometries for all seismic source models, with an emphasis on new source model components. We highlight the effects that two new model components—incorporation of slip rates from combined geodetic-geologic inversions and the incorporation of adaptively smoothed seismicity models—have on probabilistic ground motions, because these sources span multiple regions of the conterminous United States and provide important additional epistemic uncertainty for the 2014 NSHM.

  14. Detection of induced seismicity effects on ground surface using data from Sentinel 1A/1B satellites

    Science.gov (United States)

    Milczarek, W.

    2017-12-01

    Induced seismicity is the result of human activity and manifests itself in the form of shock and vibration of the ground surface. One of the most common factors causing the occurrence of induced shocks is underground mining activity. Sufficiently strong high-energy shocks may cause displacements of the ground surface. This type of shocks can have a significant impact on buildings and infrastructure. Assessment of the size and influence of induced seismicity on the ground surface is one of the major problems associated with mining activity. In Poland (Central Eastern Europe) induced seismicity occurs in the area of hard coal mining in the Upper Silesian Coal Basin and in the area of the Legnica - Głogów Copper Basin.The study presents an assessment of the use of satellite radar data (SAR) for the detection influence of induced seismicity in mining regions. Selected induced shocks from the period 2015- 2017 which occurred in the Upper Silesian Coal Basin and the Legnica - Głogów Copper Basin areas have been analyzed. In the calculations SAR data from the Sentinel 1A and Sentinel 1B satellites have been used. The results indicate the possibility of quickly and accurate detection of ground surface displacements after an induced shock. The results of SAR data processing were compared with the results from geodetic measurements. It has been shown that SAR data can be used to detect ground surface displacements on the relative small regions.

  15. Kinematic Interaction and Rocking Effects on the Seismic Response of Viaducts on Pile Foundations

    International Nuclear Information System (INIS)

    Dezi, F.; Carbonari, S.; Leoni, G.

    2008-01-01

    This paper is aimed at providing a contribution for a more accurate and effective design of bridges founded on piles. A numerical model is employed herein to determine the stresses and displacements in the piles taking into account soil-foundation-structure interaction. A 3D finite element approach is developed for piles and superstructure whereas the soil is assumed to be a Winkler-type medium. The method is applied to single piers representative for a class of bridges. Varying the soil layers characteristics and the pile spacing (from 3 to 5 diameters), bending and axial stresses along piles as well as the pier base shear are computed. A comparison with respect to a fixed-base model is provided. Special issues such as the contribution of the soil profile, of the local amplification and of the rocking at the foundation level are discussed. Soil-structure interaction is found to be essential for effective design of bridges especially for squat piers and soft soil

  16. Evaluation of stress and saturation effects on seismic velocity and electrical resistivity - laboratory testing of rock samples

    Science.gov (United States)

    Vilhelm, Jan; Jirků, Jaroslav; Slavík, Lubomír; Bárta, Jaroslav

    2016-04-01

    Repository, located in a deep geological formation, is today considered the most suitable solution for disposal of spent nuclear fuel and high-level waste. The geological formations, in combination with an engineered barrier system, should ensure isolation of the waste from the environment for thousands of years. For long-term monitoring of such underground excavations special monitoring systems are developed. In our research we developed and tested monitoring system based on repeated ultrasonic time of flight measurement and electrical resistivity tomography (ERT). As a test site Bedřichov gallery in the northern Bohemia was selected. This underground gallery in granitic rock was excavated using Tunnel Boring Machine (TBM). The seismic high-frequency measurements are performed by pulse-transmission technique directly on the rock wall using one seismic source and three receivers in the distances of 1, 2 and 3 m. The ERT measurement is performed also on the rock wall using 48 electrodes. The spacing between electrodes is 20 centimeters. An analysis of relation of seismic velocity and electrical resistivity on water saturation and stress state of the granitic rock is necessary for the interpretation of both seismic monitoring and ERT. Laboratory seismic and resistivity measurements were performed. One series of experiments was based on uniaxial loading of dry and saturated granitic samples. The relation between stress state and ultrasonic wave velocities was tested separately for dry and saturated rock samples. Other experiments were focused on the relation between electrical resistivity of the rock sample and its saturation level. Rock samples with different porosities were tested. Acknowledgments: This work was partially supported by the Technology Agency of the Czech Republic, project No. TA 0302408

  17. Bayesian seismic AVO inversion

    Energy Technology Data Exchange (ETDEWEB)

    Buland, Arild

    2002-07-01

    A new linearized AVO inversion technique is developed in a Bayesian framework. The objective is to obtain posterior distributions for P-wave velocity, S-wave velocity and density. Distributions for other elastic parameters can also be assessed, for example acoustic impedance, shear impedance and P-wave to S-wave velocity ratio. The inversion algorithm is based on the convolutional model and a linearized weak contrast approximation of the Zoeppritz equation. The solution is represented by a Gaussian posterior distribution with explicit expressions for the posterior expectation and covariance, hence exact prediction intervals for the inverted parameters can be computed under the specified model. The explicit analytical form of the posterior distribution provides a computationally fast inversion method. Tests on synthetic data show that all inverted parameters were almost perfectly retrieved when the noise approached zero. With realistic noise levels, acoustic impedance was the best determined parameter, while the inversion provided practically no information about the density. The inversion algorithm has also been tested on a real 3-D dataset from the Sleipner Field. The results show good agreement with well logs but the uncertainty is high. The stochastic model includes uncertainties of both the elastic parameters, the wavelet and the seismic and well log data. The posterior distribution is explored by Markov chain Monte Carlo simulation using the Gibbs sampler algorithm. The inversion algorithm has been tested on a seismic line from the Heidrun Field with two wells located on the line. The uncertainty of the estimated wavelet is low. In the Heidrun examples the effect of including uncertainty of the wavelet and the noise level was marginal with respect to the AVO inversion results. We have developed a 3-D linearized AVO inversion method with spatially coupled model parameters where the objective is to obtain posterior distributions for P-wave velocity, S

  18. The effect of random mass, stiffness and eccentricity parameters on seismic response of torsional system

    International Nuclear Information System (INIS)

    Ghafory-Ashtiany, M.

    2001-01-01

    In this paper, the effect of random eccentricity, mass and stiffness parameter on the dynamic characteristics of structure and story shear and torsional response has been comprehensively examined. Numerical results are obtained for a five-story torsional building excited by random excitation with various damping ration and frequency parameter values using both approaches of response calculations-a more accurate complex mode and an approximate normal mode have been used. The results show that the introduction of eccentricity in a direction introduces torsional moments in the system and reduces the direct story shear. For a safe design, eccentricity should be neglected in the calculations for shear, and a value of 0.05 of radius of gyration for calculation of torsional moment should be considered, even if a structure is intended to be symmetrical

  19. Effect of lumped mass and support stiffness on pipe seismic response

    International Nuclear Information System (INIS)

    Chang, P.S.Y.

    1986-01-01

    In performing pipe stress analysis, generic support stiffness values are typically used to predict the response of the piping systems. Consistent design of every support to match the generic stiffness value is difficult. The difference between the actual and generic stiffness may affect the results of pipe stresses and support reactions. The objective of this study is to develop an acceptance criteria for the actual support stiffness and to avoid unnecessary reanalysis. The support mass in the restraint direction and mass within the pipe span can also affect the piping system behavior and this study will discuss this mass effect as well. Added mass and change in support stiffness will cause the piping system to shift frequency

  20. Development of an evaluation method for seismic isolation systems of nuclear power facilities. Seismic design analysis methods for crossover piping system

    International Nuclear Information System (INIS)

    Tai, Koichi; Sasajima, Keisuke; Fukushima, Shunsuke; Takamura, Noriyuki; Onishi, Shigenobu

    2014-01-01

    This paper provides seismic design analysis methods suitable for crossover piping system, which connects between seismic isolated building and non-isolated building in the seismic isolated nuclear power plant. Through the numerical study focused on the main steam crossover piping system, seismic response spectrum analysis applying ISM (Independent Support Motion) method with SRSS combination or CCFS (Cross-oscillator, Cross-Floor response Spectrum) method has found to be quite effective for the seismic design of multiply supported crossover piping system. (author)

  1. Development of the DQFM method to consider the effect of correlation of component failures in seismic PSA of nuclear power plant

    International Nuclear Information System (INIS)

    Watanabe, Yuichi; Oikawa, Tetsukuni; Muramatsu, Ken

    2003-01-01

    This paper presents a new calculation method for considering the effect of correlation of component failures in seismic probabilistic safety assessment (PSA) of nuclear power plants (NPPs) by direct quantification of Fault Tree (FT) using the Monte Carlo simulation (DQFM) and discusses the effect of correlation on core damage frequency (CDF). In the DQFM method, occurrence probability of a top event is calculated as follows: (1) Response and capacity of each component are generated according to their probability distribution. In this step, the response and capacity can be made correlated according to a set of arbitrarily given correlation data. (2) For each component whether the component is failed or not is judged by comparing the response and the capacity. (3) The status of each component, failure or success, is assigned as either TRUE or FALSE in a Truth Table, which represents the logical structure of the FT to judge the occurrence of the top event. After this trial is iterated sufficient times, the occurrence probability of the top event is obtained as the ratio of the occurrence number of the top event to the number of total iterations. The DQFM method has the following features compared with the minimal cut set (MCS) method used in the well known Seismic Safety Margins Research Program (SSMRP). While the MCS method gives the upper bound approximation for occurrence probability of an union of MCSs, the DQFM method gives more exact results than the upper bound approximation. Further, the DQFM method considers the effect of correlation on the union and intersection of component failures while the MCS method considers only the effect on the latter. The importance of these features in seismic PSA of NPPs are demonstrated by an example calculation and a calculation of CDF in a seismic PSA. The effect of correlation on CDF was evaluated by the DQFM method and was compared with that evaluated in the application study of the SSMRP methodology. In the application

  2. Effect of longitudinal profile on the seismic anaysis of concrete gravity dams

    International Nuclear Information System (INIS)

    El-Nady, A.; Ghobarah, A.; Aziz, T.S.

    1992-01-01

    The traditional three-dimensional analysis of concrete gravity dams is expensive and very difficult. An alternate approach is to divide the dam into substructures. Each monolith is considered as a substructure and its degrees of freedom are reduced to those on the contact surfaces with the adjacent monoliths as well as a few Ritz vectors. Using this procedure high accuracy was achieved using a reasonable number of degrees of freedom. The analysis is carried out in the frequency domain to account for the frequency dependent parameters in the reservoir substructure. The procedure was tested and compared to typical three-dimensional analysis and was found to give high accuracy. A simplified cross section of gravity dams with different longitudinal profiles was studied using the substructuring procedure as well as a typical two-dimensional analysis. The results obtained show a significant variation in dynamic properties of the dam from that calculated assuming two-dimensional analysis. Furthermore, the response of the dam varies significantly when including the effect of longitudinal profile of the structure. It is concluded that the two-dimensional representation of the structure may substantially overestimate the response of the dam, depending on its longitudinal profile, especially when keyed joints are used in the construction. 13 refs., 5 figs., 4 tabs

  3. Effects of porosity on seismic velocities, elastic moduli and Poisson's ratios of solid materials and rocks

    Directory of Open Access Journals (Sweden)

    Chengbo Yu

    2016-02-01

    Full Text Available The generalized mixture rule (GMR is used to provide a unified framework for describing Young's (E, shear (G and bulk (K moduli, Lame parameter (λ, and P- and S-wave velocities (Vp and Vs as a function of porosity in various isotropic materials such as metals, ceramics and rocks. The characteristic J values of the GMR for E, G, K and λ of each material are systematically different and display consistent correlations with the Poisson's ratio of the nonporous material (ν0. For the materials dominated by corner-shaped pores, the fixed point at which the effective Poisson's ratio (ν remains constant is at ν0 = 0.2, and J(G > J(E > J(K > J(λ and J(G  0.2 and ν0  J(Vp and J(Vs  0.2 and ν0  0.2 and ν0 = 0.2, respectively. For natural rocks containing thin-disk-shaped pores parallel to mineral cleavages, grain boundaries and foliation, however, the ν fixed point decreases nonlinearly with decreasing pore aspect ratio (α: width/length. With increasing depth or pressure, cracks with smaller α values are progressively closed, making the ν fixed point rise and finally reach to the point at ν0 = 0.2.

  4. Site Effect and Expected Seismic Performance of Buildings in Palestine- Case Study: Nablus City

    International Nuclear Information System (INIS)

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

    2008-01-01

    The effects of local geology on ground-motion amplification and building damage were studied in Palestine-West Bank. Nakamura's method of microtremor analysis was applied in this study. The measurements showed significantly higher amplification in the frequency range of building vulnerability in different parts of Nablus city. This finding is consistent with the distribution of the earthquake damage grades in the urban areas struck by the 11 February 2004 earthquake (ML = 5.2) with a focal depth of 17 km beneath the northeastern part of the Dead Sea Basin. Quite large differences in amplification between around 1 and 9 were computed between the eastern and western rims of the city. The downtown built in the central part of the city on soft clay, marl and valley deposits, whereas the northern and southern parts of urban areas in Nablus city lying on mountains consist of consolidated carbonates bedrock. In the central part of the city and at the rims, where the thickness of fluvial deposits and soft formations is about 15 m, amplifications between 6.74 and 8.67 for dominant natural period range of 0.8-1.1 sec were obtained. On the southern and northern mountains, which are located on limestone rocks covered with a thin layer of soil, the amplification in the same frequency range was low. Calculating the natural period of the existing common buildings (T b ) in the studied area (buildings with 10-12 stories), by using the dynamic analysis method. The values of T b obtained were much closed to the site dominant natural period (Ts). The findings of this study indicate that the expected differences in damage grades for urban areas in Nablus city could be attributed to variations in the thickness and physical properties of Tertiary-Quaternary sediments, which appear to be rather heterogeneous

  5. The effects of pulse pressure from seismic water gun technology on Northern Pike

    Science.gov (United States)

    Gross, Jackson A.; Irvine, Kathryn M.; Wilmoth, Siri K.; Wagner, Tristany L.; Shields, Patrick A; Fox, Jeffrey R.

    2013-01-01

    We examined the efficacy of sound pressure pulses generated from a water gun for controlling invasive Northern Pike Esox lucius. Pulse pressures from two sizes of water guns were evaluated for their effects on individual fish placed at a predetermined random distance. Fish mortality from a 5,620.8-cm3 water gun (peak pressure source level = 252 dB referenced to 1 μP at 1 m) was assessed every 24 h for 168 h, and damage (intact, hematoma, or rupture) to the gas bladder, kidney, and liver was recorded. The experiment was replicated with a 1,966.4-cm3 water gun (peak pressure source level = 244 dB referenced to 1 μP at 1 m), but fish were euthanized immediately. The peak sound pressure level (SPLpeak), peak-to-peak sound pressure level (SPLp-p), and frequency spectrums were recorded, and the cumulative sound exposure level (SELcum) was subsequently calculated. The SPLpeak, SPLp-p, and SELcum were correlated, and values varied significantly by treatment group for both guns. Mortality increased and organ damage was greater with decreasing distance to the water gun. Mortality (31%) by 168 h was only observed for Northern Pike exhibiting the highest degree of organ damage. Mortality at 72 h and 168 h postexposure was associated with increasing SELcum above 195 dB. The minimum SELcum calculated for gas bladder rupture was 199 dB recorded at 9 m from the 5,620.8-cm3 water gun and 194 dB recorded at 6 m from the 1,966.4-cm3water gun. Among Northern Pike that were exposed to the large water gun, 100% of fish exposed at 3 and 6 m had ruptured gas bladders, and 86% exposed at 9 m had ruptured gas bladders. Among fish that were exposed to pulse pressures from the smaller water gun, 78% exhibited gas bladder rupture. Results from these initial controlled experiments underscore the potential of water guns as a tool for controlling Northern Pike.

  6. Angola Seismicity MAP

    Science.gov (United States)

    Neto, F. A. P.; Franca, G.

    2014-12-01

    The purpose of this job was to study and document the Angola natural seismicity, establishment of the first database seismic data to facilitate consultation and search for information on seismic activity in the country. The study was conducted based on query reports produced by National Institute of Meteorology and Geophysics (INAMET) 1968 to 2014 with emphasis to the work presented by Moreira (1968), that defined six seismogenic zones from macro seismic data, with highlighting is Zone of Sá da Bandeira (Lubango)-Chibemba-Oncócua-Iona. This is the most important of Angola seismic zone, covering the epicentral Quihita and Iona regions, geologically characterized by transcontinental structure tectono-magmatic activation of the Mesozoic with the installation of a wide variety of intrusive rocks of ultrabasic-alkaline composition, basic and alkaline, kimberlites and carbonatites, strongly marked by intense tectonism, presenting with several faults and fractures (locally called corredor de Lucapa). The earthquake of May 9, 1948 reached intensity VI on the Mercalli-Sieberg scale (MCS) in the locality of Quihita, and seismic active of Iona January 15, 1964, the main shock hit the grade VI-VII. Although not having significant seismicity rate can not be neglected, the other five zone are: Cassongue-Ganda-Massano de Amorim; Lola-Quilengues-Caluquembe; Gago Coutinho-zone; Cuima-Cachingues-Cambândua; The Upper Zambezi zone. We also analyzed technical reports on the seismicity of the middle Kwanza produced by Hidroproekt (GAMEK) region as well as international seismic bulletins of the International Seismological Centre (ISC), United States Geological Survey (USGS), and these data served for instrumental location of the epicenters. All compiled information made possible the creation of the First datbase of seismic data for Angola, preparing the map of seismicity with the reconfirmation of the main seismic zones defined by Moreira (1968) and the identification of a new seismic

  7. A seismic recording device

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, R; Kind, A G; Thompson, S R

    1983-06-08

    A method and a device for noting the moment of an explosion on a seismic recording is proposed, in which the moment of the explosion is recorded as a result of a break in an electrical circuit under the effects of the explosive charge used to excite the seismic waves. The electrical circuit being broken is connected to the same energy source as the electric detonator which initiates the explosion, which is attached to a high frequency, alternating current source, where the circuit being broken is either the primary or the secondary winding of a transformer, through which the electric detonator is switched in to the source. The moment the circuit is broken is determined from the ceasation of current in the circuit or by the sharp rise in voltage in the broken sector. The method makes it possible to more precisely fix the moment of the break than the existing methods. When insulated copper wires are used the recording of the time occurs 100 microseconds after the explosion.

  8. New seismic source `BLASTER` for seismic survey; Hasaiyaku wo shingen to shite mochiita danseiha tansa

    Energy Technology Data Exchange (ETDEWEB)

    Koike, G; Yoshikuni, Y [OYO Corp., Tokyo (Japan)

    1996-10-01

    Built-up weight and vacuole have been conceived as seismic sources without using explosive. There have been problems that they have smaller energy to generate elastic wave than explosive, and that they have inferior working performance. Concrete crushing explosive is tried to use as a new seismic source. It is considered to possess rather large seismic generating energy, and it is easy to handle from the viewpoint of safety. Performance as seismic source and applicability to exploration works of this crushing explosive were compared with four kinds of seismic sources using dynamite, dropping weight, shot-pipe utilizing shot vacuole, and impact by wooden maul. When considered by the velocity amplitude, the seismic generating energy of the crushing explosive of 120 g is about one-fifth of dynamite of 100 g. Elastic wave generated includes less high frequency component than that by dynamite, and similar to that using seismic source without explosive, such as the weight dropping. The maximum seismic receiving distance obtained by the seismic generation was about 100 m. This was effective for the slope survey with the exploration depth between 20 m and 30 m. 1 ref., 9 figs., 2 tabs.

  9. Eastern US seismic hazard characterization update

    International Nuclear Information System (INIS)

    Savy, J.B.; Boissonnade, A.C.; Mensing, R.W.; Short, C.M.

    1993-06-01

    In January 1989, LLNL published the results of a multi-year project, funded by NRC, on estimating seismic hazard at nuclear plant sites east of the Rockies. The goal of this study was twofold: to develop a good central estimate (median) of the seismic hazard and to characterize the uncertainty in the estimates of this hazard. In 1989, LLNL was asked by DOE to develop site specific estimates of the seismic hazard at the Savannah River Site (SRS) in South Carolina as part of the New Production Reactor (NPR) project. For the purpose of the NPR, a complete review of the methodology and of the data acquisition process was performed. Work done under the NPR project has shown that first order improvement in the estimates of the uncertainty (i.e., lower mean hazard values) could be easily achieved by updating the modeling of the seismicity and ground motion attenuation uncertainty. To this effect, NRC sponsored LLNL to perform a reelicitation to update the seismicity and ground motion experts' inputs and to revise methods to combine seismicity and ground motion inputs in the seismic hazard analysis for nuclear power plant sites east of the Rocky Mountains. The objective of the recent study was to include the first order improvements that reflect the latest knowledge in seismicity and ground motion modeling and produce an update of all the hazard results produced in the 1989 study. In particular, it had been demonstrated that eliciting seismicity information in terms of rates of earthquakes rather than a- and b-values, and changing the elicitation format to a one-on-one interview, improved our ability to express the uncertainty of earthquake rates of occurrence at large magnitudes. Thus, NRC sponsored this update study to refine the model of uncertainty, and to re-elicitate of the experts' interpretations of the zonation and seismicity, as well as to reelicitate the ground motion models, based on current state of knowledge

  10. Global Compilation of InSAR Earthquake Source Models: Comparisons with Seismic Catalogues and the Effects of 3D Earth Structure

    Science.gov (United States)

    Weston, J. M.; Ferreira, A. M.; Funning, G. J.

    2010-12-01

    should map epicentral locations accurately, this allows us to obtain a first independent estimate of epicentral location errors in the seismic catalogues. InSAR depths are systematically shallower than those in the EHB catalogue with differences of 5-10km; we discuss the possible reasons for these differences, which allow us to place constraints on the accuracy of both ICMT and EHB depth determinations. Finally, we carry out long-period surface-wave CMT inversions using four different 3D global tomographic models and two different forward modelling techniques to assess the effect of inaccurate wave propagation formulations and/or 3D Earth structure on the source parameter comparisons. We find that comparing InSAR source models with the range of seismic solutions that we obtain is a useful way to assess limitations in the earthquake models, notably in identifying inaccuracies in the retrieved earthquake slip distribution using InSAR. Moreover, we find that using more accurate formulations, together with the best fitting Earth models, further reduces differences between the seismic moment determined using InSAR and seismic data.

  11. The Effects of Structure and Source Complexity on Waveforms: Crustal Structure of Tibet and the Recovery of Complex Seismic Sources

    Science.gov (United States)

    1989-09-07

    range from 43-49 km. Kono [1974] examined the Bouguer gravity in eastern Nepal and found that the crust under the Himalayas is much thinner than...December 13, 1982 Yemen earthquake is of considerable interest because it is historically the first earthquake in the southwestern Arabian Peninsula...southwest boundary of the Arabian Peninsula, which is relatively seismically inactive, has been characterized by Ambraseys and Meiville (1983) as couple

  12. Geochemical features and effects on deep-seated fluids during the May-June 2012 southern Po Valley seismic sequence

    Directory of Open Access Journals (Sweden)

    Francesco Italiano

    2012-10-01

    Full Text Available A periodic sampling of the groundwaters and dissolved and free gases in selected deep wells located in the area affected by the May-June 2012 southern Po Valley seismic sequence has provided insight into seismogenic-induced changes of the local aquifer systems. The results obtained show progressive changes in the fluid geochemistry, allowing it to be established that deep-seated fluids were mobilized during the seismic sequence and reached surface layers along faults and fractures, which generated significant geochemical anomalies. The May-June 2012 seismic swarm (mainshock on May 29, 2012, M 5.8; 7 shocks M >5, about 200 events 3 > M > 5 induced several modifications in the circulating fluids. This study reports the preliminary results obtained for the geochemical features of the waters and gases collected over the epicentral area from boreholes drilled at different depths, thus intercepting water and gases with different origins and circulation. The aim of the investigations was to improve our knowledge of the fluids circulating over the seismic area (e.g. origin, provenance, interactions, mixing of different components, temporal changes. This was achieved by collecting samples from both shallow and deep-drilled boreholes, and then, after the selection of the relevant sites, we looked for temporal changes with mid-to-long-term monitoring activity following a constant sampling rate. This allowed us to gain better insight into the relationships between the fluid circulation and the faulting activity. The sampling sites are listed in Table 1, along with the analytical results of the gas phase. […

  13. Geomorphology and seismic risk

    Science.gov (United States)

    Panizza, Mario

    1991-07-01

    The author analyses the contributions provided by geomorphology in studies suited to the assessment of seismic risk: this is defined as function of the seismic hazard, of the seismic susceptibility, and of the vulnerability. The geomorphological studies applicable to seismic risk assessment can be divided into two sectors: (a) morpho-neotectonic investigations conducted to identify active tectonic structures; (b) geomorphological and morphometric analyses aimed at identifying the particular situations that amplify or reduce seismic susceptibility. The morpho-neotectonic studies lead to the identification, selection and classification of the lineaments that can be linked with active tectonic structures. The most important geomorphological situations that can condition seismic susceptibility are: slope angle, debris, morphology, degradational slopes, paleo-landslides and underground cavities.

  14. Analyzing the effect of large rotations on the seismic response of structures subjected to foundation local uplift

    Directory of Open Access Journals (Sweden)

    El Abbas N.

    2016-01-01

    Full Text Available This work deals with seismic analysis of structures by taking into account soil-structure interaction where the structure is modeled by an equivalent flexible beam mounted on a rigid foundation that is supported by a Winkler like soil. The foundation is assumed to undergo local uplift and the rotations are considered to be large. The coupling of the system is represented by a series of springs and damping elements that are distributed over the entire width of the foundation. The non-linear equations of motion of the system were derived by taking into account the equilibrium of the coupled foundation-structure system where the structure was idealized as a single-degree-of-freedom. The seismic response of the structure was calculated under the occurrence of foundation uplift for both large and small rotations. The non-linear differential system of equations was integrated by using the Matlab command ode15s. The maximum response has been determined as function of the intensity of the earthquake, the slenderness of the structure and the damping ratio. It was found that considering local uplift with small rotations of foundation under seismic loading leads to unfavorable structural response in comparison with the case of large rotations.

  15. Advanced Seismic While Drilling System

    Energy Technology Data Exchange (ETDEWEB)

    Robert Radtke; John Fontenot; David Glowka; Robert Stokes; Jeffery Sutherland; Ron Evans; Jim Musser

    2008-06-30

    A breakthrough has been discovered for controlling seismic sources to generate selectable low frequencies. Conventional seismic sources, including sparkers, rotary mechanical, hydraulic, air guns, and explosives, by their very nature produce high-frequencies. This is counter to the need for long signal transmission through rock. The patent pending SeismicPULSER{trademark} methodology has been developed for controlling otherwise high-frequency seismic sources to generate selectable low-frequency peak spectra applicable to many seismic applications. Specifically, we have demonstrated the application of a low-frequency sparker source which can be incorporated into a drill bit for Drill Bit Seismic While Drilling (SWD). To create the methodology of a controllable low-frequency sparker seismic source, it was necessary to learn how to maximize sparker efficiencies to couple to, and transmit through, rock with the study of sparker designs and mechanisms for (a) coupling the sparker-generated gas bubble expansion and contraction to the rock, (b) the effects of fluid properties and dynamics, (c) linear and non-linear acoustics, and (d) imparted force directionality. After extensive seismic modeling, the design of high-efficiency sparkers, laboratory high frequency sparker testing, and field tests were performed at the University of Texas Devine seismic test site. The conclusion of the field test was that extremely high power levels would be required to have the range required for deep, 15,000+ ft, high-temperature, high-pressure (HTHP) wells. Thereafter, more modeling and laboratory testing led to the discovery of a method to control a sparker that could generate low frequencies required for deep wells. The low frequency sparker was successfully tested at the Department of Energy Rocky Mountain Oilfield Test Center (DOE RMOTC) field test site in Casper, Wyoming. An 8-in diameter by 26-ft long SeismicPULSER{trademark} drill string tool was designed and manufactured by TII

  16. 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)

  17. Seismic motions from project Rulison

    Energy Technology Data Exchange (ETDEWEB)

    Loux, P C [Environmental Research Corp., Alexandria, VA (United States)

    1970-05-15

    In the range from a few to a few hundred km, seismic measurements from the Rulison event are shown and compared with experimentally and analytically derived pre-event estimates. Seismograms, peak accelerations, and response spectra are given along with a description of the associated geologic environment. Techniques used for the pre-event estimates are identified with emphasis on supportive data and on Rulison results. Of particular interest is the close-in seismic frequency content which is expected to contain stronger high frequency components. This higher frequency content translates into stronger accelerations within the first tens of km, which in turn affect safety preparations. Additionally, the local geologic structure at nearby population centers must be considered. Pre-event reverse profile refraction surveys are used to delineate the geology at Rifle, Rulison, Grand Valley, and other sites. The geologic parameters are then used as input to seismic amplification models which deliver estimates of local resonant frequencies. Prediction of such resonances allows improved safety assurance against seismic effects hazards. (author)

  18. Considering soil-structure interaction effects in the equivalent static analysis method of the Iranian of the Iranian seismic building code

    International Nuclear Information System (INIS)

    Shakib, H.; Dehghani Ashkezari, G.

    2002-01-01

    In this study, based on the equivalent static analysis method of the Iranian seismic code, an algorithm is presented to consider the soil-structure interaction (SSI) effects. Modifications of free field motion and structural properties like period and damping due to soil situation are considered in the proposed algorithm. An increase for fundamental period of structure and a modification (usually increase) for it's effective damping are observed. The increase of period is due to the flexibility of the soil foundation and modification of damping is due to the dissipating energy in soil. In order to propose the relative expressions in the presented algorithm, the soil-structure analyses of 8, 10, 13 and 16 stories frames are carried out. By considering the NEHRP soil-structure interaction algorithm and findings of soil-structure interaction analyses carried out in this study, the algorithm based on the equivalent static analysis method of the Iranian seismic building code to consider the effect of soil-structure interaction

  19. Realistic Features in Analysing the Effect of the Seismic Motion upon Localized Structures Considering Base Isolation Influence on Their Dynamic Behaviour

    Science.gov (United States)

    Apostol, Bogdan Felix; Florin Balan, Stefan; Ionescu, Constantin

    2017-12-01

    The effects of the earthquakes on buildings and the concept of seismic base isolation are investigated by using the model of the vibrating bar embedded at one end. The normal modes and the eigenfrequencies of the bar are highlighted and the amplification of the response due to the excitation of the normal modes (eigenmodes) is computed. The effect is much enhanced at resonance, for oscillating shocks which contain eigenfrequencies of the bar. Also, the response of two linearly joined bars with one end embedded is calculated. It is shown that for very different elastic properties the eigenfrequencies are due mainly to the “softer” bar. The effect of the base isolation in seismic structural engineering is assessed by formulating the model of coupled harmonic oscillators, as a simplified model for the structure building-foundation viewed as two coupled vibrating bars. The coupling decreases the lower eigenfrequencies of the structure and increases the higher ones. Similar amplification factors are derived for coupled oscillators at resonance with an oscillating shock.

  20. Enhanced seismic criteria for piping

    International Nuclear Information System (INIS)

    Touboul, F. . E-mail francoise.touboul@cea.fr; Blay, N.; Sollogoub, P.; Chapuliot, S.

    2006-01-01

    In situ or laboratory experiments have shown that piping systems exhibit satisfactory seismic behavior. Seismic motion is not severe enough to significantly damage piping systems unless large differential motions of anchorage are imposed. Nevertheless, present design criteria for piping are very severe and require a large number of supports, which creates overly rigid piping systems. CEA, in collaboration with EDF, FRAMATOME and IRSN, has launched a large R and D program on enhanced design methods which will be less severe, but still conservative, and compatible with defect justification during operation. This paper presents the background of the R and D work on this matter, and CEA proposed equations. Our approach is based on the difference between the real behavior (or the best estimated computed one) with the one supposed by codified methods. Codified criteria are applied on an elastically calculated behavior that can be significantly different from the real one: the effect of plasticity may be very meaningful, even with low incursion in the plastic domain. Moreover, and particularly in piping systems, the elastic follow-up effect affects stress distribution for both seismic and thermal loads. For seismic load, we have proposed to modify the elastic moment limitation, based on the interpretation of experimental results on piping systems. The methods have been validated on more industrial cases, and some of the consequences of the changes have been studied: modification of the drawings and of the number of supports, global displacements, forces in the supports, stability of potential defects, etc. The basic aim of the studies undertaken is to make a decision on the stress classification problem, one that is not limited to seismic induced stresses, and to propose simplified methods for its solution

  1. Seismic excitation by space shuttles

    Science.gov (United States)

    Kanamori, H.; Mori, J.; Sturtevant, B.; Anderson, D.L.; Heaton, T.

    1992-01-01

    Shock waves generated by the space shuttles Columbia (August 13, 1989), Atlantis (April 11, 1991) and Discovery (September 18, 1991) on their return to Edwards Air Force Base, California, were recorded by TERRAscope (Caltech's broadband seismic network), the Caltech-U.S.G.S Southern California Seismic Network (SCSN), and the University of Southern California (USC) Los Angeles Basin Seismic Network. The spatial pattern of the arrival times exhibits hyperbolic shock fronts from which the path, velocity and altitude of the space shuttle could be determined. The shock wave was acoustically coupled to the ground, converted to a seismic wave, and recorded clearly at the broadband TERRAscope stations. The acoustic coupling occurred very differently depending on the conditions of the Earth's surface surrounding the station. For a seismic station located on hard bedrock, the shock wave (N wave) was clearly recorded with little distortion. Aside from the N wave, very little acoustic coupling of the shock wave energy to the ground occurred at these sites. The observed N wave record was used to estimate the overpressure of the shock wave accurately; a pressure change of 0.5 to 2.2 mbars was obtained. For a seismic station located close to the ocean or soft sedimentary basins, a significant amount of shock wave energy was transferred to the ground through acoustic coupling of the shock wave and the oceanic Rayleigh wave. A distinct topography such as a mountain range was found effective to couple the shock wave energy to the ground. Shock wave energy was also coupled to the ground very effectively through large man made structures such as high rise buildings and offshore oil drilling platforms. For the space shuttle Columbia, in particular, a distinct pulse having a period of about 2 to 3 seconds was observed, 12.5 s before the shock wave, with a broadband seismograph in Pasadena. This pulse was probably excited by the high rise buildings in downtown Los Angeles which were

  2. Seismic hazard map of the western hemisphere

    Science.gov (United States)

    Shedlock, K.M.; Tanner, J.G.

    1999-01-01

    horizontal force a building should be able to withstand during an earthquake. This seismic hazard map of the Americas depicts the likely level of short-period ground motion from earthquakes in a fifty-year window. Short-period ground motions effect short-period structures (e.g., one-to-two story buildings). The largest seismic hazard values in the western hemisphere generally occur in areas that have been, or are likely to be, the sites of the largest plate boundary earthquakes. Although the largest earthquakes ever recorded are the 1960 Chile and 1964 Alaska subduction zone earthquakes, the largest seismic hazard (PGA) value in the Americas is in Southern California (U.S.), along the San Andreas fault.

  3. Seismic hazard map of the western hemisphere

    Directory of Open Access Journals (Sweden)

    J. G. Tanner

    1999-06-01

    specify the horizontal force a building should be able to withstand during an earthquake. This seismic hazard map of the Americas depicts the likely level of short-period ground motion from earthquakes in a fifty-year window. Short-period ground motions effect short-period structures (e.g., one-to-two story buildings. The largest seismic hazard values in the western hemisphere generally occur in areas that have been, or are likely to be, the sites of the largest plate boundary earthquakes. Although the largest earthquakes ever recorded are the 1960 Chile and 1964 Alaska subduction zone earthquakes, the largest seismic hazard (PGA value in the Americas is in Southern California (U.S., along the San Andreas fault.

  4. Seismic Design of a Single Bored Tunnel: Longitudinal Deformations and Seismic Joints

    Science.gov (United States)

    Oh, J.; Moon, T.

    2018-03-01

    The large diameter bored tunnel passing through rock and alluvial deposits subjected to seismic loading is analyzed for estimating longitudinal deformations and member forces on the segmental tunnel liners. The project site has challenges including high hydrostatic pressure, variable ground profile and high seismic loading. To ensure the safety of segmental tunnel liner from the seismic demands, the performance-based two-level design earthquake approach, Functional Evaluation Earthquake and Safety Evaluation Earthquake, has been adopted. The longitudinal tunnel and ground response seismic analyses are performed using a three-dimensional quasi-static linear elastic and nonlinear elastic discrete beam-spring elements to represent segmental liner and ground spring, respectively. Three components (longitudinal, transverse and vertical) of free-field ground displacement-time histories evaluated from site response analyses considering wave passage effects have been applied at the end support of the strain-compatible ground springs. The result of the longitudinal seismic analyses suggests that seismic joint for the mitigation measure requiring the design deflection capacity of 5-7.5 cm is to be furnished at the transition zone between hard and soft ground condition where the maximum member forces on the segmental liner (i.e., axial, shear forces and bending moments) are induced. The paper illustrates how detailed numerical analyses can be practically applied to evaluate the axial and curvature deformations along the tunnel alignment under difficult ground conditions and to provide the seismic joints at proper locations to effectively reduce the seismic demands below the allowable levels.

  5. NCSRR digital seismic network in Romania

    International Nuclear Information System (INIS)

    Aldea, A.; Albota, E.; Demetriu, S.; Poiata, N.; Kashima, T.

    2007-01-01

    Digital seismic instrumentation donated by Japan International Cooperation Agency (JICA) to the National Center for Seismic Risk Reduction (NCSRR, Romania) allowed the installation in 2003 of a new Romanian seismic network. In 2005-2006 the network was developed by investments from NCSRR within the budget ensured by Ministry of Transports, Construction and Tourism (MTCT). The NCSRR seismic network contains three types of instrumentation: (i) free-field stations - outside the capital city Bucharest (8 accelerometers), (ii) instrumented buildings - in Bucharest (5 buildings), and (iii) stations with free-field and borehole sensors - in Bucharest (8 sites with ground surface sensor and sensors in 15 boreholes with depths up to 153 m). Since its installation, the NCSRR network recorded more than 170 seismic motions from 26 earthquakes with moment magnitudes ranging from 3.2 to 6.0. The seismic instrumentation was accompanied by investigations of ground conditions and site response: PS logging tests, single-station and array microtremor measurements. The development of seismic monitoring in Romania is a major contribution of JICA Project, creating the premises for a better understanding and modelling of earthquake ground motion, site effects and building response. (authors)

  6. Research on performance-based seismic design criteria

    Institute of Scientific and Technical Information of China (English)

    谢礼立; 马玉宏

    2002-01-01

    The seismic design criterion adopted in the existing seismic design codes is reviewed. It is pointed out that the presently used seismic design criterion is not satisfied with the requirements of nowadays social and economic development. A new performance-based seismic design criterion that is composed of three components is presented in this paper. It can not only effectively control the economic losses and casualty, but also ensure the building(s function in proper operation during earthquakes. The three components are: classification of seismic design for buildings, determination of seismic design intensity and/or seismic design ground motion for controlling seismic economic losses and casualties, and determination of the importance factors in terms of service periods of buildings. For controlling the seismic human losses, the idea of socially acceptable casualty level is presented and the (Optimal Economic Decision Model( and (Optimal Safe Decision Model( are established. Finally, a new method is recommended for calculating the importance factors of structures by adjusting structures service period on the base of more important structure with longer service period than the conventional ones. Therefore, the more important structure with longer service periods will be designed for higher seismic loads, in case the exceedance probability of seismic hazard in different service period is same.

  7. 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)

  8. Effect of the surface roughness on the seismic signal generated by a single rock impact: insight from laboratory experiments

    Science.gov (United States)

    Bachelet, Vincent; Mangeney, Anne; de Rosny, Julien; Toussaint, Renaud

    2016-04-01

    The seismic signal generated by rockfalls, landslides or avalanches is a unique tool to detect, characterize and monitor gravitational flow activity, with strong implication in terms of natural hazard monitoring. Indeed, as natural flows travel down the slope, they apply stresses on the ground, generating seismic waves in a wide frequency band. Our ultimate objective is to relate the granular flow properties to the generated signals that result from the different physical processes involved. We investigate here the more simple process: the impact of a single bead on a rough surface. Farin et al. [2015] have already shown theoretically and experimentally the existence of a link between the properties of an impacting bead (mass and velocity) on smooth surfaces, and the emitted signal (radiated elastic energy and mean frequency). This demonstrates that the single impactor properties can be deduced from the form of the emitted signal. We extend this work here by investigating the impact of single beads and gravels on rough and erodible surfaces. Experimentally, we drop glass and steel beads of diameters from 2 mm to 10 mm on a PMMA plate. The roughness of this last is obtained by gluing 3mm-diameter glass beads on one of its face. Free beads have been also added to get erodible beds. We track the dropped impactor motion, times between impacts and the generated acoustic waves using two fast cameras and 8 accelerometers. Cameras are used in addition to estimate the impactor rotation. We investigate the energy balance during the impact process, especially how the energy restitution varies as a function of the energy lost through acoustic waves. From these experiments, we clearly observe that even if more dissipative processes are involved (friction, grain reorganization, etc.), the single bead scaling laws obtained on smooth surfaces remain valid. A main result of this work is to quantify the fluctuations of the characteristic quantities such as the bounce angle, the

  9. Time-dependent seismic tomography

    Science.gov (United States)

    Julian, B.R.; Foulger, G.R.

    2010-01-01

    Of methods for measuring temporal changes in seismic-wave speeds in the Earth, seismic tomography is among those that offer the highest spatial resolution. 3-D tomographic methods are commonly applied in this context by inverting seismic wave arrival time data sets from different epochs independently and assuming that differences in the derived structures represent real temporal variations. This assumption is dangerous because the results of independent inversions would differ even if the structure in the Earth did not change, due to observational errors and differences in the seismic ray distributions. The latter effect may be especially severe when data sets include earthquake swarms or aftershock sequences, and may produce the appearance of correlation between structural changes and seismicity when the wave speeds are actually temporally invariant. A better approach, which makes it possible to assess what changes are truly required by the data, is to invert multiple data sets simultaneously, minimizing the difference between models for different epochs as well as the rms arrival-time residuals. This problem leads, in the case of two epochs, to a system of normal equations whose order is twice as great as for a single epoch. The direct solution of this system would require twice as much memory and four times as much computational effort as would independent inversions. We present an algorithm, tomo4d, that takes advantage of the structure and sparseness of the system to obtain the solution with essentially no more effort than independent inversions require. No claim to original US government works Journal compilation ?? 2010 RAS.

  10. Seismic design standardization of nuclear facilities

    International Nuclear Information System (INIS)

    Reddy, G.R.; Vaze, K.K.

    2011-01-01

    Full text: Structures, Systems and Components (SSCs) of Nuclear Facilities have to be designed for normal operating loads such as dead weight, pressure, temperature etc., and accidental loads such as earthquakes, floods, extreme, wind air craft impact, explosions etc. Man made accidents such as aircraft impact, explosions etc., some times may be considered as design basis event and some times taken care by providing administrative controls. This will not be possible in the case of natural events such as earthquakes, flooding, extreme winds etc. Among natural events earthquakes are considered as most devastating and need to be considered as design basis event. It is generally felt design of SSCs for earthquake loads is very time consuming and expensive. Conventional seismic design approaches demands for large number of supports for systems and components. This results in large space occupation and in turn creates difficulties for maintenance and in service inspection of systems and components. In addition, complete exercise of design need to be repeated for plants being located at different sites due to different seismic demands. However, advanced seismic response control methods will help to standardize the seismic design meeting the safety and economy. These methods adopt passive, semi active and active devices, and base isolators to control the seismic response. In nuclear industry, it is advisable to go for passive devices to control the seismic responses. Ideally speaking, these methods will make the designs made for normal loads can also satisfy the seismic demand without calling for change in material, geometry, layout etc. in the SSCs. This paper explain the basic ideas of seismic response control methods, demonstrate the effectiveness of control methods through case studies and eventually give the procedure to be adopted for seismic design standardization of nuclear facilities

  11. 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.

  12. 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

  13. Seismic texture classification. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Vinther, R.

    1997-12-31

    The seismic texture classification method, is a seismic attribute that can both recognize the general reflectivity styles and locate variations from these. The seismic texture classification performs a statistic analysis for the seismic section (or volume) aiming at describing the reflectivity. Based on a set of reference reflectivities the seismic textures are classified. The result of the seismic texture classification is a display of seismic texture categories showing both the styles of reflectivity from the reference set and interpolations and extrapolations from these. The display is interpreted as statistical variations in the seismic data. The seismic texture classification is applied to seismic sections and volumes from the Danish North Sea representing both horizontal stratifications and salt diapers. The attribute succeeded in recognizing both general structure of successions and variations from these. Also, the seismic texture classification is not only able to display variations in prospective areas (1-7 sec. TWT) but can also be applied to deep seismic sections. The seismic texture classification is tested on a deep reflection seismic section (13-18 sec. TWT) from the Baltic Sea. Applied to this section the seismic texture classification succeeded in locating the Moho, which could not be located using conventional interpretation tools. The seismic texture classification is a seismic attribute which can display general reflectivity styles and deviations from these and enhance variations not found by conventional interpretation tools. (LN)

  14. Effects of a significant New Madrid Seismic Zone event on oil and natural gas pipelines and their cascading effects to critical infrastructures

    Science.gov (United States)

    Fields, Damon E.

    Critical Infrastructure Protection (CIP) is a construct that relates preparedness and responsiveness to natural or man-made disasters that involve vulnerable assets deemed essential for the functioning of our economy and society. Infrastructure systems (power grids, bridges, airports, etc.) are vulnerable to disastrous types of events--natural or man-made. Failures of these systems can have devastating effects on communities and entire regions. CIP relates our willingness, ability, and capability to defend, mitigate, and re-constitute those assets that succumb to disasters affecting one or more infrastructure sectors. This qualitative research utilized ethnography and employed interviews with subject matter experts (SMEs) from various fields of study regarding CIP with respect to oil and natural gas pipelines in the New Madrid Seismic Zone. The study focused on the research question: What can be done to mitigate vulnerabilities in the oil and natural gas infrastructures, along with the potential cascading effects to interdependent systems, associated with a New Madrid fault event? The researcher also analyzed National Level Exercises (NLE) and real world events, and associated After Action Reports (AAR) and Lessons Learned (LL) in order to place a holistic lens across all infrastructures and their dependencies and interdependencies. Three main themes related to the research question emerged: (a) preparedness, (b) mitigation, and (c) impacts. These themes comprised several dimensions: (a) redundancy, (b) node hardening, (c) education, (d) infrastructure damage, (e) cascading effects, (f) interdependencies, (g) exercises, and (h) earthquake readiness. As themes and dimensions are analyzed, they are considered against findings in AARs and LL from previous real world events and large scale exercise events for validation or rejection.

  15. Effectiveness of two conventional methods for seismic retrofit of steel and RC moment resisting frames based on damage control criteria

    Science.gov (United States)

    Beheshti Aval, Seyed Bahram; Kouhestani, Hamed Sadegh; Mottaghi, Lida

    2017-07-01

    This study investigates the efficiency of two types of rehabilitation methods based on economic justification that can lead to logical decision making between the retrofitting schemes. Among various rehabilitation methods, concentric chevron bracing (CCB) and cylindrical friction damper (CFD) were selected. The performance assessment procedure of the frames is divided into two distinct phases. First, the limit state probabilities of the structures before and after rehabilitation are investigated. In the second phase, the seismic risk of structures in terms of life safety and financial losses (decision variables) using the recently published FEMA P58 methodology is evaluated. The results show that the proposed retrofitting methods improve the serviceability and life safety performance levels of steel and RC structures at different rates when subjected to earthquake loads. Moreover, these procedures reveal that financial losses are greatly decreased, and were more tangible by the application of CFD rather than using CCB. Although using both retrofitting methods reduced damage state probabilities, incorporation of a site-specific seismic hazard curve to evaluate mean annual occurrence frequency at the collapse prevention limit state caused unexpected results to be obtained. Contrary to CFD, the collapse probability of the structures retrofitted with CCB increased when compared with the primary structures.

  16. Seismic isolation structure for pool-type LMFBR - isolation building with vertically isolated floor for NSSS

    International Nuclear Information System (INIS)

    Sakurai, A.; Shiojiri, H.; Aoyagi, S.; Matsuda, T.; Fujimoto, S.; Sasaki, Y.; Hirayama, H.

    1987-01-01

    The NSSS isolation floor vibration characteristics were made clear. Especially, the side support bearing (rubber bearing) is effective for horizontal floor motion restraint and rocking motion control. Seismic isolation effects for responses of the reactor components can be sufficiently expected, using the vertical seismic isolation floor. From the analytical and experimental studies, the following has been concluded: (1) Seismic isolation structure, which is suitable for large pool-type LMFBR, were proposed. (2) Seismic response characteristics of the seismic isolation structure were investigated. It was made clear that the proposed seismic isolation (Combination of the isolated building and the isolated NSSS floor) was effective. (orig./HP)

  17. Man-caused seismicity of Kuzbass

    Science.gov (United States)

    Emanov, Alexandr; Emanov, Alexey; Leskova, Ekaterina; Fateyev, Alexandr

    2010-05-01

    . A spatial displacement of activations along with mine working has been found. An impact of technogeneous factors on behavior of seismic process was investigated. It was demonstrated that industrial explosions in neighboring open-casts have no pronounced effect on seismic process near lavas. Stoppage of mole work in lavas leads to simultaneous changes in man-caused seismicity. The number of technogeneous earthquakes is halved. The earthquakes of small powers remain, but such slack lead to occasional though more strong technogeneous earthquakes.

  18. On the effect of the 3-D regional geology on the seismic design of critical structures: the case of the Kashiwazaki-Kariwa Nuclear Power Plant

    Science.gov (United States)

    Gatti, F.; Lopez-Caballero, F.; Clouteau, D.; Paolucci, R.

    2018-05-01

    In this study, numerical investigation is performed on a realistic source-to-site earthquake scenario, with the aim to assess the role of complex 3-D geological structures on the predicted wavefield. With this respect, the paper pointedly targets the seismic response of nuclear power plants in near-field conditions and the verification of some simplified assumptions commonly adopted for earthquake ground motion prediction and site effects analysis. To this purpose, the Kashiwazaki-Kariwa Nuclear Power Plant (Japan) is assumed as reference case-study. In 2007, the nuclear site and its surroundings were struck by the Niigata-Ken Chūetsu-Oki seismic sequence, which caused some of the peak ground motion design limits to be largely overpassed. The dense observation network deployed at the site recorded a highly incoherent and impulsive earthquake ground motion. Many studies argued that the intricate syncline-anticline geology lying underneath the nuclear facility was highly responsible of the observed seismic response. Therefore, a physics-based numerical model of the epicentral area is built-up (≈60 km wide) and tested for small aftershocks, so to discount the effect of extended source on the synthetic site-response. The numerical model (based on the Spectral Element Method) reproduces the source-to-site wave propagation by embracing the effects of the surface topography along with the presence of the Japan Sea (i.e. the bathymetry, the coastline and the fluid-solid interaction). Broad-band (0-5 Hz) synthetic waveforms are obtained for two different aftershocks, located at the two opposite sides of the nuclear facility, aiming to assess the influence of the incidence angle the radiated wave field impinges the foldings beneath it. The effect of the folding presence is assessed by comparing it to a subhorizontally layered geology, in terms of numerical outcome, and by highlighting the differences with respect to the observations. The presence of an intricate geology

  19. 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.

  20. THK: CLB Crossed Linear Bearing Seismic Isolators

    International Nuclear Information System (INIS)

    Toniolo, Roberto

    2008-01-01

    This text highlights the new seismic isolation technology called CLB (Crossed Linear Bearing), which is made of linear guides with recirculating steel ball technology. It describes specifications and building characteristics, provides examples of seismic isolation and application functionalities and shows experimental data. Since 1994, the constant commitment by Japan to develop diversified anti-seismic systems based on the precise needs of the structures to protect and the areas where they were built has led to the creation of important synergy between the research institutions of leading Japanese companies and THK's Centre for Research and Development. Their goal has been to develop new technology and solutions to allow seismic isolation to be effective in the following cases:

  1. Using Seismic Interferometry to Investigate Seismic Swarms

    Science.gov (United States)

    Matzel, E.; Morency, C.; Templeton, D. C.

    2017-12-01

    Seismicity provides a direct means of measuring the physical characteristics of active tectonic features such as fault zones. Hundreds of small earthquakes often occur along a fault during a seismic swarm. This seismicity helps define the tectonically active region. When processed using novel geophysical techniques, we can isolate the energy sensitive to the fault, itself. Here we focus on two methods of seismic interferometry, ambient noise correlation (ANC) and the virtual seismometer method (VSM). ANC is based on the observation that the Earth's background noise includes coherent energy, which can be recovered by observing over long time periods and allowing the incoherent energy to cancel out. The cross correlation of ambient noise between a pair of stations results in a waveform that is identical to the seismogram that would result if an impulsive source located at one of the stations was recorded at the other, the Green function (GF). The calculation of the GF is often stable after a few weeks of continuous data correlation, any perturbations to the GF after that point are directly related to changes in the subsurface and can be used for 4D monitoring.VSM is a style of seismic interferometry that provides fast, precise, high frequency estimates of the Green's function (GF) between earthquakes. VSM illuminates the subsurface precisely where the pressures are changing and has the potential to image the evolution of seismicity over time, including changes in the style of faulting. With hundreds of earthquakes, we can calculate thousands of waveforms. At the same time, VSM collapses the computational domain, often by 2-3 orders of magnitude. This allows us to do high frequency 3D modeling in the fault region. Using data from a swarm of earthquakes near the Salton Sea, we demonstrate the power of these techniques, illustrating our ability to scale from the far field, where sources are well separated, to the near field where their locations fall within each other

  2. The Seismic Analyzer: Interpreting and Illustrating 2D Seismic Data

    OpenAIRE

    Patel, Daniel; Giertsen, Christopher; Thurmond, John; Gjelberg, John; Gröller, Eduard

    2008-01-01

    We present a toolbox for quickly interpreting and illustrating 2D slices of seismic volumetric reflection data. Searching for oil and gas involves creating a structural overview of seismic reflection data to identify hydrocarbon reservoirs. We improve the search of seismic structures by precalculating the horizon structures of the seismic data prior to interpretation. We improve the annotation of seismic structures by applying novel illustrative rendering algorithms tailored to seism...

  3. Seismic Risk Perception compared with seismic Risk Factors

    Science.gov (United States)

    Crescimbene, Massimo; La Longa, Federica; Pessina, Vera; Pino, Nicola Alessandro; Peruzza, Laura

    2016-04-01

    The communication of natural hazards and their consequences is one of the more relevant ethical issues faced by scientists. In the last years, social studies have provided evidence that risk communication is strongly influenced by the risk perception of people. In order to develop effective information and risk communication strategies, the perception of risks and the influencing factors should be known. A theory that offers an integrative approach to understanding and explaining risk perception is still missing. To explain risk perception, it is necessary to consider several perspectives: social, psychological and cultural perspectives and their interactions. This paper presents the results of the CATI survey on seismic risk perception in Italy, conducted by INGV researchers on funding by the DPC. We built a questionnaire to assess seismic risk perception, with a particular attention to compare hazard, vulnerability and exposure perception with the real data of the same factors. The Seismic Risk Perception Questionnaire (SRP-Q) is designed by semantic differential method, using opposite terms on a Likert scale to seven points. The questionnaire allows to obtain the scores of five risk indicators: Hazard, Exposure, Vulnerability, People and Community, Earthquake Phenomenon. The questionnaire was administered by telephone interview (C.A.T.I.) on a statistical sample at national level of over 4,000 people, in the period January -February 2015. Results show that risk perception seems be underestimated for all indicators considered. In particular scores of seismic Vulnerability factor are extremely low compared with house information data of the respondents. Other data collected by the questionnaire regard Earthquake information level, Sources of information, Earthquake occurrence with respect to other natural hazards, participation at risk reduction activities and level of involvement. Research on risk perception aims to aid risk analysis and policy-making by

  4. Simulation of Co-Seismic Off-Fault Stress Effects: Influence of Fault Roughness and Pore Pressure Coupling

    Science.gov (United States)

    Fälth, B.; Lund, B.; Hökmark, H.

    2017-12-01

    Aiming at improved safety assessment of geological nuclear waste repositories, we use dynamic 3D earthquake simulations to estimate the potential for co-seismic off-fault distributed fracture slip. Our model comprises a 12.5 x 8.5 km strike-slip fault embedded in a full space continuum where we apply a homogeneous initial stress field. In the reference case (Case 1) the fault is planar and oriented optimally for slip, given the assumed stress field. To examine the potential impact of fault roughness, we also study cases where the fault surface has undulations with self-similar fractal properties. In both the planar and the undulated cases the fault has homogeneous frictional properties. In a set of ten rough fault models (Case 2), the fault friction is equal to that of Case 1, meaning that these models generate lower seismic moments than Case 1. In another set of ten rough fault models (Case 3), the fault dynamic friction is adjusted such that seismic moments on par with that of Case 1 are generated. For the propagation of the earthquake rupture we adopt the linear slip-weakening law and obtain Mw 6.4 in Case 1 and Case 3, and Mw 6.3 in Case 2 (35 % lower moment than Case 1). During rupture we monitor the off-fault stress evolution along the fault plane at 250 m distance and calculate the corresponding evolution of the Coulomb Failure Stress (CFS) on optimally oriented hypothetical fracture planes. For the stress-pore pressure coupling, we assume Skempton's coefficient B = 0.5 as a base case value, but also examine the sensitivity to variations of B. We observe the following: (I) The CFS values, and thus the potential for fracture slip, tend to increase with the distance from the hypocenter. This is in accordance with results by other authors. (II) The highest CFS values are generated by quasi-static stress concentrations around fault edges and around large scale fault bends, where we obtain values of the order of 10 MPa. (III) Locally, fault roughness may have a

  5. Seismic safety in conducting large-scale blasts

    Science.gov (United States)

    Mashukov, I. V.; Chaplygin, V. V.; Domanov, V. P.; Semin, A. A.; Klimkin, M. A.

    2017-09-01

    In mining enterprises to prepare hard rocks for excavation a drilling and blasting method is used. With the approach of mining operations to settlements the negative effect of large-scale blasts increases. To assess the level of seismic impact of large-scale blasts the scientific staff of Siberian State Industrial University carried out expertise for coal mines and iron ore enterprises. Determination of the magnitude of surface seismic vibrations caused by mass explosions was performed using seismic receivers, an analog-digital converter with recording on a laptop. The registration results of surface seismic vibrations during production of more than 280 large-scale blasts at 17 mining enterprises in 22 settlements are presented. The maximum velocity values of the Earth’s surface vibrations are determined. The safety evaluation of seismic effect was carried out according to the permissible value of vibration velocity. For cases with exceedance of permissible values recommendations were developed to reduce the level of seismic impact.

  6. IAEA establishes International Seismic Safety Centre

    International Nuclear Information System (INIS)

    2008-01-01

    Full text: The IAEA today officially inaugurated an international centre to coordinate efforts for protecting nuclear installations against the effects of earthquakes. The International Seismic Safety Centre (ISSC), which has been established within the IAEA's Department of Nuclear Safety and Security, will serve as a focal point on seismic safety for nuclear installations worldwide. ISSC will assist countries on the assessment of seismic hazards of nuclear facilities to mitigate the consequences of strong earthquakes. 'With safety as our first priority, it is vital that we pool all expert knowledge available worldwide to assist nuclear operators and regulators to be well prepared for coping with major seismic events,' said Antonio Godoy, Acting Head of the IAEA's Engineering Safety Section and leader of the ISSC. 'The creation of the ISSC represents the culmination of three decades of the IAEA's active and recognized involvement in this matter through the development of an updated set of safety standards and the assistance to Member States for their application.' To further seismic safety at nuclear installations worldwide, the ISSC will: - Promote knowledge sharing among the international community in order to avoid or mitigate the consequences of extreme seismic events on nuclear installations; - Support countries through advisory services and training courses; and - Enhance seismic safety by utilizing experience gained from previous seismic events in member states. The centre is supported by a scientific committee of high-level experts from academic, industrial and nuclear safety authorities that will advise the ISSC on implementation of its programme. Experts have been nominated from seven specialized areas, including geology and tectonics, seismology, seismic hazard, geotechnical engineering, structural engineering, equipment, and seismic risk. Japan and the United States have both contributed initial funds for creation of the centre, which will be based at

  7. Advances in experimental seismic engineering

    International Nuclear Information System (INIS)

    Muthumani, K.; Gopalakrishnan, N.; Sathish Kumar, K.; Iyer, Nagesh R.

    2011-01-01

    Seismic testing plays a key role in better understanding physical phenomena, validating and improving analysis and design methods, and qualifying sensitive equipment. There are several different experimental techniques that can be used to test the response of structures to verify their seismic performance. These include (i) Quasi-static testing (ii) Shake table testing, (iii) Effective force testing (iv) Pseudodynamic testing and (v) Real-time dynamic hybrid testing. The sophisticated shaking table facilities and modern data acquisition and processing methods using high speed computers have made it possible to improve the accuracy and reliability of the experimental data, and to increase the number of gauge points, thus yielding a more detailed picture of the structural behavior. Lifeline structures like nuclear power plants and thermal power

  8. Time-domain study of tectonic strain-release effects on seismic waves from underground nuclear explosions

    International Nuclear Information System (INIS)

    Nakanishi, K.K.; Sherman, N.W.

    1982-09-01

    Tectonic strain release affects both the amplitude and phase of seismic waves from underground nuclear explosions. Surface wave magnitudes are strongly affected by the component of tectonic strain release in the explosion. Amplitudes and radiation patterns of surface waves from explosions with even small tectonic components change magnitudes significantly and show a strong dependence on receiver locations. A thrust-slip source superimposed on an isotropic explosion can explain observed reversals in waveform at different azimuths and phase delays between normal and reversed Rayleigh waves. The mechanism of this reversal is due to the phase relationship between reasonable explosion and tectonic release sources. Spallation or an unusual source time function are not required. The observations of Shagan River events imply thrust-slip motion along faults in a northwest-southeast direction, which is consistent with regional tectonics

  9. ANALYSIS FOR EFFECT OF FPS-TYPED TMD CONTROLLING SEISMIC RESPONSES%FPS型TMD控震效应分析

    Institute of Scientific and Technical Information of China (English)

    李大望; 关罡; 霍达

    2001-01-01

    Based on the differential vibration equations of the multi-layer shear-type st ructure controlled by FPS-TMD,the seismic response laws of the structure are ca lculated and analyzed;the results display that the earthquake responses of the b uilding structures can be improved with a reasonable designed FPS-TMD.%基于FPS(Friction Pendulum System)型TMD(Turned Mass Damper)控制的多层剪切型结构振动微分方程,通过时程计算分析了FPS型TMD控震响应规律。结果表明,合理设计的FPS型TMD 控振系统可以改善结构的振动响应。

  10. Nonlinear seismic analysis of a large sodium pump

    International Nuclear Information System (INIS)

    Huang, S.N.

    1985-01-01

    The bearings and seismic bumpers used in a large sodium pump of a typical breeder reactor plant may need to be characterized by nonlinear springs and gaps. Then, nonlinear seismic analysis utilizing the time-history method is an effective way to predict the pump behaviors during seismic events - especially at those bearing and seismic bumper areas. In this study, synthesized time histories were developed based on specified seismic response spectra. A nonlinear seismic analysis was then conducted and results were compared with those obtained by linear seismic analysis using the response spectrum method. In contrast to some previous nonlinear analysis trends, the bearing impact forces predicted by nonlinear analysis were higher than those obtained by the response spectrum method. This might be due to the larger gaps and stiffer bearing supports used in this specific pump. However, at locations distant from the impact source, the nonlinear seismic analysis has predicted slightly less responses than those obtained by linear seismic analysis. The seismically induced bearing impact forces were used to study the friction induced thermal stresses on the hydrostatic bearing and to predict the coastdown time of the pump. Results and discussions are presented

  11. Nonlinear seismic analysis of a large sodium pump

    International Nuclear Information System (INIS)

    Huang, S.N.

    1985-01-01

    The bearings and seismic bumpers used in a large sodium pump of a typical breeder reactor plant may need to be characterized by nonlinear springs and gaps. Then, nonlinear seismic analysis utilizing the time-history method is an effective way to predict the pump behaviors during seismic events, especially at those bearing and seismic bumper areas. In this study, synthesized time histories were developed based on specified seismic response spectra. A nonlinear seismic analysis was then conducted and results were compared with those obtained by linear seismic analysis using the response spectrum method. In contrast to some previous nonlinear analysis trends, the bearing impact forces predicted by nonlinear analysis were higher than those obtained by the response spectrum method. This might be due to the larger gaps and stiffer bearing supports used in this specific pump. However, at locations distant from the impact source, the nonlinear seismic analysis has predicted slightly less responses than those obtained by linear seismic analysis. The seismically induced bearing impact forces were used to study the friction induced thermal stresses on the hydrostatic bearing and to predict the coastdown time of the pump. Results and discussions are presented

  12. Seismic isolation of buildings using composite foundations based on metamaterials

    Science.gov (United States)

    Casablanca, O.; Ventura, G.; Garescı, F.; Azzerboni, B.; Chiaia, B.; Chiappini, M.; Finocchio, G.

    2018-05-01

    Metamaterials can be engineered to interact with waves in entirely new ways, finding application on the nanoscale in various fields such as optics and acoustics. In addition, acoustic metamaterials can be used in large-scale experiments for filtering and manipulating seismic waves (seismic metamaterials). Here, we propose seismic isolation based on a device that combines some properties of seismic metamaterials (e.g., periodic mass-in-mass systems) with that of a standard foundation positioned right below the building for isolation purposes. The concepts on which this solution is based are the local resonance and a dual-stiffness structure that preserves large (small) rigidity for compression (shear) effects. In other words, this paper introduces a different approach to seismic isolation by using certain principles of seismic metamaterials. The experimental demonstrator tested on the laboratory scale exhibits a spectral bandgap that begins at 4.5 Hz. Within the bandgap, it filters more than 50% of the seismic energy via an internal dissipation process. Our results open a path toward the seismic resilience of buildings and a critical infrastructure to shear seismic waves, achieving higher efficiency compared to traditional seismic insulators and passive energy-dissipation systems.

  13. Seismic sequences in the Sombrero Seismic Zone

    Science.gov (United States)

    Pulliam, J.; Huerfano, V. A.; ten Brink, U.; von Hillebrandt, C.

    2007-05-01

    The northeastern Caribbean, in the vicinity of Puerto Rico and the Virgin Islands, has a long and well-documented history of devastating earthquakes and tsunamis, including major events in 1670, 1787, 1867, 1916, 1918, and 1943. Recently, seismicity has been concentrated to the north and west of the British Virgin Islands, in the region referred to as the Sombrero Seismic Zone by the Puerto Rico Seismic Network (PRSN). In the combined seismicity catalog maintained by the PRSN, several hundred small to moderate magnitude events can be found in this region prior to 2006. However, beginning in 2006 and continuing to the present, the rate of seismicity in the Sombrero suddenly increased, and a new locus of activity developed to the east of the previous location. Accurate estimates of seismic hazard, and the tsunamigenic potential of seismic events, depend on an accurate and comprehensive understanding of how strain is being accommodated in this corner region. Are faults locked and accumulating strain for release in a major event? Or is strain being released via slip over a diffuse system of faults? A careful analysis of seismicity patterns in the Sombrero region has the potential to both identify faults and modes of failure, provided the aggregation scheme is tuned to properly identify related events. To this end, we experimented with a scheme to identify seismic sequences based on physical and temporal proximity, under the assumptions that (a) events occur on related fault systems as stress is refocused by immediately previous events and (b) such 'stress waves' die out with time, so that two events that occur on the same system within a relatively short time window can be said to have a similar 'trigger' in ways that two nearby events that occurred years apart cannot. Patterns that emerge from the identification, temporal sequence, and refined locations of such sequences of events carry information about stress accommodation that is obscured by large clouds of

  14. Seismic Creep, USA Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Seismic creep is the constant or periodic movement on a fault as contrasted with the sudden rupture associated with an earthquake. It is a usually slow deformation...

  15. BUILDING 341 Seismic Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Halle, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-06-15

    The Seismic Evaluation of Building 341 located at Lawrence Livermore National Laboratory in Livermore, California has been completed. The subject building consists of a main building, Increment 1, and two smaller additions; Increments 2 and 3.

  16. Seismic data acquisition systems

    International Nuclear Information System (INIS)

    Kolvankar, V.G.; Nadre, V.N.; Rao, D.S.

    1989-01-01

    Details of seismic data acquisition systems developed at the Bhabha Atomic Research Centre, Bombay are reported. The seismic signals acquired belong to different signal bandwidths in the band from 0.02 Hz to 250 Hz. All these acquisition systems are built around a unique technique of recording multichannel data on to a single track of an audio tape and in digital form. Techniques of how these signals in different bands of frequencies were acquired and recorded are described. Method of detecting seismic signals and its performance is also discussed. Seismic signals acquired in different set-ups are illustrated. Time indexing systems for different set-ups and multichannel waveform display systems which form essential part of the data acquisition systems are also discussed. (author). 13 refs., 6 figs., 1 tab

  17. PSMG switchgear seismic analysis

    International Nuclear Information System (INIS)

    Kuehster, C.J.

    1977-01-01

    LOFT primary coolant system motor generator (PSMG) switchgear boxes were analyzed for sliding and overturning during a seismic event. Boxes are located in TAN-650, Room B-239, with the PSMG generators. Both boxes are sufficiently anchored to the floor

  18. 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

  19. Seismic facies; Facies sismicas

    Energy Technology Data Exchange (ETDEWEB)

    Johann, Paulo Roberto Schroeder [PETROBRAS, Rio de Janeiro, RJ (Brazil). Exploracao e Producao Corporativo. Gerencia de Reservas e Reservatorios]. E-mail: johann@petrobras.com.br

    2004-11-01

    The method presented herein describes the seismic facies as representations of curves and vertical matrixes of the lithotypes proportions. The seismic facies are greatly interested in capturing the spatial distributions (3D) of regionalized variables, as for example, lithotypes, sedimentary facies groups and/ or porosity and/or other properties of the reservoirs and integrate them into the 3D geological modeling (Johann, 1997). Thus when interpreted as curves or vertical matrixes of proportions, seismic facies allow us to build a very important tool for structural analysis of regionalized variables. The matrixes have an important application in geostatistical modeling. In addition, this approach provides results about the depth and scale of the wells profiles, that is, seismic data is integrated to the characterization of reservoirs in depth maps and in high resolution maps. The link between the different necessary technical phases involved in the classification of the segments of seismic traces is described herein in groups of predefined traces of two approaches: a) not supervised and b) supervised by the geological knowledge available on the studied reservoir. The multivariate statistical methods used to obtain the maps of the seismic facies units are interesting tools to be used to provide a lithostratigraphic and petrophysical understanding of a petroleum reservoir. In the case studied these seismic facies units are interpreted as representative of the depositional system as a part of the Namorado Turbiditic System, Namorado Field, Campos Basin.Within the scope of PRAVAP 19 (Programa Estrategico de Recuperacao Avancada de Petroleo - Strategic Program of Advanced Petroleum Recovery) some research work on algorithms is underway to select new optimized attributes to apply seismic facies. One example is the extraction of attributes based on the wavelet transformation and on the time-frequency analysis methodology. PRAVAP is also carrying out research work on an

  20. An investigation of major influences on the seismic response of APR1400 reactor vessel internals - 15145

    International Nuclear Information System (INIS)

    Byun, Y.J.; Kim, J.G.; Sung, K.K.; Lee, D.H.

    2015-01-01

    This paper deals with 3 topics concerning the APR1400 reactor vessel internals (RVI) seismic analysis: nonlinear problems, approaches to account for uncertainties of seismic model, and dynamic responses to various seismic excitations. First, the noticeable nonlinear characteristics of the RVI seismic model are discussed, and the modeling methods for properly simulating the nonlinear behaviors of RVI under seismic loads are presented. By applying these methods to the seismic model, the seismic analysis can correctly predict the dynamic response of RVI. Next, two approaches to account for the uncertainties of seismic model are evaluated: the time history broadening method, and the sensitivity analysis based on NUREG-0800, Section 4.2, Appendix A. From the evaluation results, it is confirmed that the time history broadening method employed in the seismic analysis of APR1400 RVI sufficiently accounts for the uncertainty of seismic model. Finally, the response characteristics of APR1400 RVI to various seismic excitations are investigated. The seismic excitations corresponding to various soil profiles, including the effects of cracked and un-cracked concrete stiffness on the reactor containment building structure, are used as forcing functions. From this study, the effects of various site conditions on the dynamic response of APR1400 RVI are identified. As a result, the enveloped seismic responses obtained from this study will contribute to the development of RVI seismic design that covers a wide range of potential site conditions. (authors)

  1. Seismic Consequence Abstraction

    International Nuclear Information System (INIS)

    Gross, M.

    2004-01-01

    The primary purpose of this model report is to develop abstractions for the response of engineered barrier system (EBS) components to seismic hazards at a geologic repository at Yucca Mountain, Nevada, and to define the methodology for using these abstractions in a seismic scenario class for the Total System Performance Assessment - License Application (TSPA-LA). A secondary purpose of this model report is to provide information for criticality studies related to seismic hazards. The seismic hazards addressed herein are vibratory ground motion, fault displacement, and rockfall due to ground motion. The EBS components are the drip shield, the waste package, and the fuel cladding. The requirements for development of the abstractions and the associated algorithms for the seismic scenario class are defined in ''Technical Work Plan For: Regulatory Integration Modeling of Drift Degradation, Waste Package and Drip Shield Vibratory Motion and Seismic Consequences'' (BSC 2004 [DIRS 171520]). The development of these abstractions will provide a more complete representation of flow into and transport from the EBS under disruptive events. The results from this development will also address portions of integrated subissue ENG2, Mechanical Disruption of Engineered Barriers, including the acceptance criteria for this subissue defined in Section 2.2.1.3.2.3 of the ''Yucca Mountain Review Plan, Final Report'' (NRC 2003 [DIRS 163274])

  2. Seismic Consequence Abstraction

    Energy Technology Data Exchange (ETDEWEB)

    M. Gross

    2004-10-25

    The primary purpose of this model report is to develop abstractions for the response of engineered barrier system (EBS) components to seismic hazards at a geologic repository at Yucca Mountain, Nevada, and to define the methodology for using these abstractions in a seismic scenario class for the Total System Performance Assessment - License Application (TSPA-LA). A secondary purpose of this model report is to provide information for criticality studies related to seismic hazards. The seismic hazards addressed herein are vibratory ground motion, fault displacement, and rockfall due to ground motion. The EBS components are the drip shield, the waste package, and the fuel cladding. The requirements for development of the abstractions and the associated algorithms for the seismic scenario class are defined in ''Technical Work Plan For: Regulatory Integration Modeling of Drift Degradation, Waste Package and Drip Shield Vibratory Motion and Seismic Consequences'' (BSC 2004 [DIRS 171520]). The development of these abstractions will provide a more complete representation of flow into and transport from the EBS under disruptive events. The results from this development will also address portions of integrated subissue ENG2, Mechanical Disruption of Engineered Barriers, including the acceptance criteria for this subissue defined in Section 2.2.1.3.2.3 of the ''Yucca Mountain Review Plan, Final Report'' (NRC 2003 [DIRS 163274]).

  3. 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

  4. Horizontal Acoustic Barriers for Protection from Seismic Waves

    Directory of Open Access Journals (Sweden)

    Sergey V. Kuznetsov

    2011-01-01

    Full Text Available The basic idea of a seismic barrier is to protect an area occupied by a building or a group of buildings from seismic waves. Depending on nature of seismic waves that are most probable in a specific region, different kinds of seismic barriers can be suggested. Herein, we consider a kind of a seismic barrier that represents a relatively thin surface layer that prevents surface seismic waves from propagating. The ideas for these barriers are based on one Chadwick's result concerning nonpropagation condition for Rayleigh waves in a clamped half-space, and Love's theorem that describes condition of nonexistence for Love waves. The numerical simulations reveal that to be effective the length of the horizontal barriers should be comparable to the typical wavelength.

  5. Use of experience data for DOE seismic evaluations

    International Nuclear Information System (INIS)

    Barlow, M.W.; Budnitz, R.; Eder, S.J.; Eli, M.W.

    1993-01-01

    As dictated by DOE Order 5480.28, seismic evaluations of essential systems and components at DOE facilities will be conducted over the next several years. For many of these systems and components, few, if any, seismic requirements applied to the original design, procurement, installation, and maintenance process. Thus the verification of the seismic adequacy of existing systems and components presents a difficult challenge. DOE has undertaken development of the criteria and procedures for these seismic evaluations that will maximize safety benefits in a timely and cost effective manner. As demonstrated in previous applications at DOE facilities and by the experience from the commercial nuclear power industry, use of experience data for these evaluations is the only viable option for most existing systems and components. This paper describes seismic experience data, the needs at DOE facilities, the precedent of application at nuclear power plants and DOE facilities, and the program being put in place for the seismic verification task ahead for DOE

  6. Seismic analysis of steam generator and parameter sensitivity studies

    International Nuclear Information System (INIS)

    Qian Hao; Xu Dinggen; Yang Ren'an; Liang Xingyun

    2013-01-01

    Background: The steam generator (SG) serves as the primary means for removing the heat generated within the reactor core and is part of the reactor coolant system (RCS) pressure boundary. Purpose: Seismic analysis in required for SG, whose seismic category is Cat. I. Methods: The analysis model of SG is created with moisture separator assembly and tube bundle assembly herein. The seismic analysis is performed with RCS pipe and Reactor Pressure Vessel (RPV). Results: The seismic stress results of SG are obtained. In addition, parameter sensitivities of seismic analysis results are studied, such as the effect of another SG, support, anti-vibration bars (AVBs), and so on. Our results show that seismic results are sensitive to support and AVBs setting. Conclusions: The guidance and comments on these parameters are summarized for equipment design and analysis, which should be focused on in future new type NPP SG's research and design. (authors)

  7. Comparison between seismic and domestic risk in moderate seismic hazard prone region: the Grenoble City (France test site

    Directory of Open Access Journals (Sweden)

    F. Dunand

    2012-02-01

    Full Text Available France has a moderate level of seismic activity, characterized by diffuse seismicity, sometimes experiencing earthquakes of a magnitude of more than 5 in the most active zones. In this seismicity context, Grenoble is a city of major economic and social importance. However, earthquakes being rare, public authorities and the decision makers are only vaguely committed to reducing seismic risk: return periods are long and local policy makers do not have much information available. Over the past 25 yr, a large number of studies have been conducted to improve our knowledge of seismic hazard in this region. One of the decision-making concerns of Grenoble's public authorities, as managers of a large number of public buildings, is to know not only the seismic-prone regions, the variability of seismic hazard due to site effects and the city's overall vulnerability, but also the level of seismic risk and exposure for the entire city, also compared to other natural or/and domestic hazards. Our seismic risk analysis uses a probabilistic approach for regional and local hazards and the vulnerability assessment of buildings. Its applicability to Grenoble offers the advantage of being based on knowledge acquired by previous projects conducted over the years. This paper aims to compare the level of seismic risk with that of other risks and to introduce the notion of risk acceptability in order to offer guidance in the management of seismic risk. This notion of acceptability, which is now part of seismic risk consideration for existing buildings in Switzerland, is relevant in moderately seismic-prone countries like France.

  8. Seismic hazard studies in Egypt

    Directory of Open Access Journals (Sweden)

    Abuo El-Ela A. Mohamed

    2012-12-01

    Full Text Available The study of earthquake activity and seismic hazard assessment of Egypt is very important due to the great and rapid spreading of large investments in national projects, especially the nuclear power plant that will be held in the northern part of Egypt. Although Egypt is characterized by low seismicity, it has experienced occurring of damaging earthquake effect through its history. The seismotectonic sitting of Egypt suggests that large earthquakes are possible particularly along the Gulf of Aqaba–Dead Sea transform, the Subduction zone along the Hellenic and Cyprean Arcs, and the Northern Red Sea triple junction point. In addition some inland significant sources at Aswan, Dahshour, and Cairo-Suez District should be considered. The seismic hazard for Egypt is calculated utilizing a probabilistic approach (for a grid of 0.5° × 0.5° within a logic-tree framework. Alternative seismogenic models and ground motion scaling relationships are selected to account for the epistemic uncertainty. Seismic hazard values on rock were calculated to create contour maps for four ground motion spectral periods and for different return periods. In addition, the uniform hazard spectra for rock sites for different 25 periods, and the probabilistic hazard curves for Cairo, and Alexandria cities are graphed. The peak ground acceleration (PGA values were found close to the Gulf of Aqaba and it was about 220 gal for 475 year return period. While the lowest (PGA values were detected in the western part of the western desert and it is less than 25 gal.

  9. Development and seismic evaluation of the seismic monitoring analysis system for HANARO

    International Nuclear Information System (INIS)

    Ryu, J. S.; Youn, D. B.; Kim, H. G.; Woo, J. S.

    2003-01-01

    Since the start of operation, the seismic monitoring system has been utilized for monitoring an earthquake at the HANARO site. The existing seismic monitoring system consists of field sensors and monitoring panel. The analog-type monitoring system with magnetic tape recorder is out-of-date model. In addition, the disadvantage of the existing system is that it does not include signal-analyzing equipment. Therefore, we have improved the analog seismic monitoring system except the field sensors into a new digital Seismic Monitoring Analysis System(SMAS) that can monitor and analyze earthquake signals. To achieve this objective for HANARO, the digital type hardware of the SMAS has been developed. The seismic monitoring and analysis programs that can provide rapid and precise information for an earthquake were developed. After the installation of the SMAS, we carried out the Site Acceptance Test (SAT) to confirm the functional capability of the newly developed system. The results of the SAT satisfy the requirements of the fabrication technical specifications. In addition, the seismic characteristics and structural integrity of the SMAS were evaluated. The results show that the cabinet of SMAS can withstand the effects of seismic loads and remain functional. This new SMAS is operating in the HANARO instrument room to acquire and analyze the signal of an earthquake

  10. Designing a low-cost effective network for monitoring large scale regional seismicity in a soft-soil region (Alsace, France)

    Science.gov (United States)

    Bès de Berc, M.; Doubre, C.; Wodling, H.; Jund, H.; Hernandez, A.; Blumentritt, H.

    2015-12-01

    The Seismological Observatory of the North-East of France (ObSNEF) is developing its monitoring network within the framework of several projects. Among these project, RESIF (Réseau sismologique et géodésique français) allows the instrumentation of broad-band seismic stations, separated by 50-100 km. With the recent and future development of geothermal industrial projects in the Alsace region, the ObSNEF is responsible for designing, building and operating a dense regional seismic network in order to detect and localize earthquakes with both a completeness magnitude of 1.5 and no clipping for M6.0. The realization of the project has to be done prior to the summer 2016Several complex technical and financial constraints constitute such a projet. First, most of the Alsace Région (150x150 km2), particularly the whole Upper Rhine Graben, is a soft-soil plain where seismic signals are dominated by a high frequency noise level. Second, all the signals have to be transmitted in near real-time. And finally, the total cost of the project must not exceed $450,000.Regarding the noise level in Alsace, in order to make a reduction of 40 dB for frequencies above 1Hz, we program to instrument into 50m deep well with post-hole sensor for 5 stations out of 8 plane new stations. The 3 remaining would be located on bedrock along the Vosges piedmont. In order to be sensitive to low-magnitude regional events, we plan to install a low-noise short-period post-hole velocimeter. In order to avoid saturation for high potentiel local events (M6.0 at 10km), this velocimeter will be coupled with a surface strong-motion sensor. Regarding the connectivity, these stations will have no wired network, which reduces linking costs and delays. We will therefore use solar panels and a 3G/GPRS network. The infrastructure will be minimal and reduced to an outdoor box on a secured parcel of land. In addition to the data-logger, we will use a 12V ruggedized computer, hosting a seed-link server for near

  11. Evaluation of performance of analytical and numerical methods to account for liquefaction effects on the seismic response of anchored quay walls

    NARCIS (Netherlands)

    van Elsäcker, W.A.; Besseling, F.; Lengkeek, H.J.; Brinkgreve, R.B.J.; de Gijt, J.G.; Jonkman, S.N.

    2017-01-01

    Liquefaction induced by earthquakes has shown to have potential devastating influence on seismic performance of anchored quay walls. Therefore, measures to mitigate liquefaction are commonly part of the design of quay walls in
    seismically active regions. Such mitigation measures are costly.

  12. Development of seismic tomography software for hybrid supercomputers

    Science.gov (United States)

    Nikitin, Alexandr; Serdyukov, Alexandr; Duchkov, Anton

    2015-04-01

    Seismic tomography is a technique used for computing velocity model of geologic structure from first arrival travel times of seismic waves. The technique is used in processing of regional and global seismic data, in seismic exploration for prospecting and exploration of mineral and hydrocarbon deposits, and in seismic engineering for monitoring the condition of engineering structures and the surrounding host medium. As a consequence of development of seismic monitoring systems and increasing volume of seismic data, there is a growing need for new, more effective computational algorithms for use in seismic tomography applications with improved performance, accuracy and resolution. To achieve this goal, it is necessary to use modern high performance computing systems, such as supercomputers with hybrid architecture that use not only CPUs, but also accelerators and co-processors for computation. The goal of this research is the development of parallel seismic tomography algorithms and software package for such systems, to be used in processing of large volumes of seismic data (hundreds of gigabytes and more). These algorithms and software package will be optimized for the most common computing devices used in modern hybrid supercomputers, such as Intel Xeon CPUs, NVIDIA Tesla accelerators and Intel Xeon Phi co-processors. In this work, the following general scheme of seismic tomography is utilized. Using the eikonal equation solver, arrival times of seismic waves are computed based on assumed velocity model of geologic structure being analyzed. In order to solve the linearized inverse problem, tomographic matrix is computed that connects model adjustments with travel time residuals, and the resulting system of linear equations is regularized and solved to adjust the model. The effectiveness of parallel implementations of existing algorithms on target architectures is considered. During the first stage of this work, algorithms were developed for execution on

  13. Detection capability of the IMS seismic network based on ambient seismic noise measurements

    Science.gov (United States)

    Gaebler, Peter J.; Ceranna, Lars

    2016-04-01

    All nuclear explosions - on the Earth's surface, underground, underwater or in the atmosphere - are banned by the Comprehensive Nuclear-Test-Ban Treaty (CTBT). As part of this treaty, a verification regime was put into place to detect, locate and characterize nuclear explosion testings at any time, by anyone and everywhere on the Earth. The International Monitoring System (IMS) plays a key role in the verification regime of the CTBT. Out of the different monitoring techniques used in the IMS, the seismic waveform approach is the most effective technology for monitoring nuclear underground testing and to identify and characterize potential nuclear events. This study introduces a method of seismic threshold monitoring to assess an upper magnitude limit of a potential seismic event in a certain given geographical region. The method is based on ambient seismic background noise measurements at the individual IMS seismic stations as well as on global distance correction terms for body wave magnitudes, which are calculated using the seismic reflectivity method. From our investigations we conclude that a global detection threshold of around mb 4.0 can be achieved using only stations from the primary seismic network, a clear latitudinal dependence for the detection threshold can be observed between northern and southern hemisphere. Including the seismic stations being part of the auxiliary seismic IMS network results in a slight improvement of global detection capability. However, including wave arrivals from distances greater than 120 degrees, mainly PKP-wave arrivals, leads to a significant improvement in average global detection capability. In special this leads to an improvement of the detection threshold on the southern hemisphere. We further investigate the dependence of the detection capability on spatial (latitude and longitude) and temporal (time) parameters, as well as on parameters such as source type and percentage of operational IMS stations.

  14. Effect of strong-column weak-beam design provision on the seismic fragility of RC frame buildings

    Science.gov (United States)

    Surana, Mitesh; Singh, Yogendra; Lang, Dominik H.

    2018-04-01

    Incremental dynamic analyses are conducted for a suite of low- and mid-rise reinforced-concrete special moment-resisting frame buildings. Buildings non-conforming and conforming to the strong-column weak-beam (SCWB) design criterion are considered. These buildings are designed for the two most severe seismic zones in India (i.e., zone IV and zone V) following the provisions of Indian Standards. It is observed that buildings non-conforming to the SCWB design criterion lead to an undesirable column failure collapse mechanism. Although yielding of columns cannot be avoided, even for buildings conforming to a SCWB ratio of 1.4, the observed collapse mechanism changes to a beam failure mechanism. This change in collapse mechanism leads to a significant increase in the building's global ductility capacity, and thereby in collapse capacity. The fragility analysis study of the considered buildings suggests that considering the SCWB design criterion leads to a significant reduction in collapse probability, particularly in the case of mid-rise buildings.

  15. Effects of FRP application on the seismic response of a masonry church in Emilia-Romagna (Italy)

    Science.gov (United States)

    Milani, Gabriele; Shehu, Rafael; Valente, Marco

    2016-12-01

    The paper presents some preliminary results of advanced Finite Element (FE) analyses on the upgrading of old masonry constructions by means of Fiber Reinforced Polymers (FRPs). The case study is a masonry Romanesque church, located in Ferrara, Emilia Romagna (Italy). The church exhibits widespread damage caused by the recent earthquake sequence occurred in 2012 about 60 km far from Ferrara with two major seismic events of magnitude 5.8 and 5.9. The main damage involved mainly the columns of the central nave and the apse. A partial detachment of the façade was observed too. First, gravity load analyses and non-linear static and dynamic analyses are performed on the church in the unretrofitted configuration. Numerical results put in evidence the insufficient strength of the apse and the columns of the naves, and the detachment of the façade. A strengthening intervention conducted by means of FRP strips is numerically analysed, assuming the behavior of the strips, especially for what concerns delamination, in agreement with Italian Guidelines. Numerical results show a quite reasonable strength improvement of the weak structural elements due to FRP application, with levels of strength higher than the minimum ones required by Italian Code.

  16. SHC, Seismic Hazard Assessment for Eastern US

    International Nuclear Information System (INIS)

    Savy, J.; Davis, B.

    2001-01-01

    magnitude-recurrence relationship. The seismic hazard methodology is based on a probability model of the occurrence and distribution of earthquakes and the attenuation of the ground motion from a source to a site. It also includes modeling of local site effects, such as soil types. The earthquake location is assumed to be uniformly distributed throughout the zone, and the ground-motion model expresses the decay with distance of the median value of a ground-motion parameter. In addition, the methodology incorporates the uncertainty in all parameters into the results. The uncertainty in the hazard is estimated by a Monte Carlo simulation process in which all levels of confidence are normalized and treated as probability values. It includes a probability distribution of the maps for each seismicity expert, distributions for the uncertainty in each of the seismicity parameters, and distribution of the ground-motion models for each of the ground-motion experts. 3 - Restrictions on the complexity of the problem: Maxima of: 150 zones per combination; 100 combinations; 96 zones; 50 simulations per attenuation expert; 50 zone clusters for alternative boundaries; 35 zones per cluster; 30 maps; 30 zones per map; 21 distances per distribution of a zone; 20 zones in a circle of influence; 20 coefficients per attenuation model; 11 seismic experts; 10 accelerations; 9 frequencies; 7 attenuation models per expert; 6 attenuation experts for ALEAS; 5 attenuation experts for COMBS; 5 return periods; 4 regions

  17. Uncertainty analysis in seismic tomography

    Science.gov (United States)

    Owoc, Bartosz; Majdański, Mariusz

    2017-04-01

    Velocity field from seismic travel time tomography depends on several factors like regularization, inversion path, model parameterization etc. The result also strongly depends on an initial velocity model and precision of travel times picking. In this research we test dependence on starting model in layered tomography and compare it with effect of picking precision. Moreover, in our analysis for manual travel times picking the uncertainty distribution is asymmetric. This effect is shifting the results toward faster velocities. For calculation we are using JIVE3D travel time tomographic code. We used data from geo-engineering and industrial scale investigations, which were collected by our team from IG PAS.

  18. Delineation of seismic source zones based on seismicity parameters ...

    Indian Academy of Sciences (India)

    these source zones were evaluated and were used in the hazard evaluation. ... seismic sources, linear and areal, were considered in the present study to model the seismic sources in the ..... taken as an authentic reference manual for iden-.

  19. Modeling the effect of the seismic wave propagation in buried continuous pipelines; Modelacion del efecto de propagacion de ondas sismicas en tuberias continuas enterradas

    Energy Technology Data Exchange (ETDEWEB)

    Melchor Garcia, Nicolas Ageo

    2005-02-15

    This work presents the state of art of the behavior of buried pipelines facing the effect of the propagation of seismic waves. Special attention has been given to the modeling of the soil-piping system. Some analytical models are presented and discussed in great detail. The purpose of this is to contribute, in particular, to the following aspects: First, it attempts to be a reference work for the geotechnical engineers facing problems related to the seismic wave propagation phenomenon in buried structures, since within the consulted literature there are many of the principles presented in here, that are related with the seismic engineering, the reaction module, as well as expressions or investigations performed in piles. Second, a cuasi-static numerical model is presented that analyzes the continuous piping through a stress vector of sinusoidal type. The analysis of the stresses and deformations that the ground transmits to the pipe is made using a ground-to-pipe interaction model. For a low level of deformations an elastic behavior of transference in the interface is considered in the inter-phase ground-piping. In the case of greater deformations it is assumed that sliding is presented because the surrounding ground presents fault by shearing stress in the surrounding ground. The analysis covers solely the case with axial deformations in straight sections. Finally, it intends to give a series of recommendations for future research works on the modeling of buried pipelines. In this work, the influence of several aspects on the response of the pipelines to the propagation of seismic waves is analyzed and discussed; such as the conditions of topography, geology, ground stratigraphy and the rigidity changes in the surrounding ground of the pipe. [Spanish] Este trabajo presenta el estado del arte sobre el comportamiento de tuberias enterradas ante efecto de programacion de ondas sismicas. Una especial atencion ha sido dada a la modelacion del sistema suelo

  20. Seismic fragility analyses

    International Nuclear Information System (INIS)

    Kostov, Marin

    2000-01-01

    In the last two decades there is increasing number of probabilistic seismic risk assessments performed. The basic ideas of the procedure for performing a Probabilistic Safety Analysis (PSA) of critical structures (NUREG/CR-2300, 1983) could be used also for normal industrial and residential buildings, dams or other structures. The general formulation of the risk assessment procedure applied in this investigation is presented in Franzini, et al., 1984. The probability of failure of a structure for an expected lifetime (for example 50 years) can be obtained from the annual frequency of failure, β E determined by the relation: β E ∫[d[β(x)]/dx]P(flx)dx. β(x) is the annual frequency of exceedance of load level x (for example, the variable x may be peak ground acceleration), P(fI x) is the conditional probability of structure failure at a given seismic load level x. The problem leads to the assessment of the seismic hazard β(x) and the fragility P(fl x). The seismic hazard curves are obtained by the probabilistic seismic hazard analysis. The fragility curves are obtained after the response of the structure is defined as probabilistic and its capacity and the associated uncertainties are assessed. Finally the fragility curves are combined with the seismic loading to estimate the frequency of failure for each critical scenario. The frequency of failure due to seismic event is presented by the scenario with the highest frequency. The tools usually applied for probabilistic safety analyses of critical structures could relatively easily be adopted to ordinary structures. The key problems are the seismic hazard definitions and the fragility analyses. The fragility could be derived either based on scaling procedures or on the base of generation. Both approaches have been presented in the paper. After the seismic risk (in terms of failure probability) is assessed there are several approaches for risk reduction. Generally the methods could be classified in two groups. The

  1. Seismic forecast using geostatistics

    International Nuclear Information System (INIS)

    Grecu, Valeriu; Mateiciuc, Doru

    2007-01-01

    The main idea of this research direction consists in the special way of constructing a new type of mathematical function as being a correlation between a computed statistical quantity and another physical quantity. This type of function called 'position function' was taken over by the authors of this study in the field of seismology with the hope of solving - at least partially - the difficult problem of seismic forecast. The geostatistic method of analysis focuses on the process of energy accumulation in a given seismic area, completing this analysis by a so-called loading function. This function - in fact a temporal function - describes the process of energy accumulation during a seismic cycle from a given seismic area. It was possible to discover a law of evolution of the seismic cycles that was materialized in a so-called characteristic function. This special function will help us to forecast the magnitude and the occurrence moment of the largest earthquake in the analysed area. Since 2000, the authors have been evolving to a new stage of testing: real - time analysis, in order to verify the quality of the method. There were five large earthquakes forecasts. (authors)

  2. 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

  3. Seismicity and seismic monitoring in the Asse salt mine

    International Nuclear Information System (INIS)

    Flach, D.; Gommlich, G.; Hente, B.

    1987-01-01

    Seismicity analyses are made in order to assess the safety of candidate sites for ultimate disposal of hazardous wastes. The report in hand reviews the seismicity history of the Asse salt mine and presents recent results of a measuring campaign made in the area. The monitoring network installed at the site supplies data and information on the regional seismicity, on seismic amplitudes under ground and above ground, and on microseismic activities. (DG) [de

  4. Seismic qualification for water chillers of nuclear power plant

    International Nuclear Information System (INIS)

    Wang Chunming

    2005-01-01

    Water chillers are important components of the electric building chilled water system of Nuclear Power Plant. In this article, we describe the seismic qualification methodology. A united method of seismic analysis and experiment testing were applied. Since the seismic classification of the evaporator, condenser and oil separator is 1F, the chillers must satisfy the function criteria. The functional and performance of the control panel were qualified by seismic test. In order to get the seismic time histories of the base of the motor, compressor and control panel, we did time histories analysis for the whole chillers using the seismic acceleration time history of the building floor on which the water chillers was located. Then, these curves were translated into required response spectrum (RRS), which were used by the seismic test of water chillers compressor sets. All passive components, such as evaporator, condenser, oil separator and support, were qualified by seismic stress analysis method. These components were verified to satisfy the standard when they were subjected to the seismic, gravitational, operational pressure and nozzle loads. The Chillers' components were qualified to the specification and the standard. The motor-compressor set and control panel were qualified to the functional and performance criteria. The applied of this methodology qualified the function of the water chillers compressor sets effectively, especially after the aging test. (author)

  5. Earthquake source studies and seismic imaging in Alaska

    Science.gov (United States)

    Tape, C.; Silwal, V.

    2015-12-01

    Alaska is one of the world's most seismically and tectonically active regions. Its enhanced seismicity, including slab seismicity down to 180 km, provides opportunities (1) to characterize pervasive crustal faulting and slab deformation through the estimation of moment tensors and (2) to image subsurface structures to help understand the tectonic evolution of Alaska. Most previous studies of earthquakes and seismic imaging in Alaska have emphasized earthquake locations and body-wave travel-time tomography. In the past decade, catalogs of seismic moment tensors have been established, while seismic surface waves, active-source data, and potential field data have been used to improve models of seismic structure. We have developed moment tensor catalogs in the regions of two of the largest sedimentary basins in Alaska: Cook Inlet forearc basin, west of Anchorage, and Nenana basin, west of Fairbanks. Our moment tensor solutions near Nenana basin suggest a transtensional tectonic setting, with the basin developing in a stepover of a left-lateral strike-slip fault system. We explore the effects of seismic wave propagation from point-source and finite-source earthquake models by performing three-dimensional wavefield simulations using seismic velocity models that include major sedimentary basins. We will use our catalog of moment tensors within an adjoint-based, iterative inversion to improve the three-dimensional tomographic model of Alaska.

  6. Delineation of seismic source zones based on seismicity parameters ...

    Indian Academy of Sciences (India)

    In the present study, an attempt has been made to delineate seismic source zones in the study area (south India) based on the seismicity parameters. Seismicity parameters and the maximum probable earthquake for these source zones were evaluated and were used in the hazard evaluation. The probabilistic evaluation of ...

  7. Seismic Microzonation for Refinement of Seismic Load Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Savich, A. I.; Bugaevskii, A. G., E-mail: office@geodyn.ru, E-mail: bugaevskiy@geodyn.ru [Center of the Office of Geodynamic Observations in the Power Sector, an affiliate of JSC “Institut Gidroproekt” (Russian Federation)

    2016-05-15

    Functional dependencies are established for the characteristics of seismic transients recorded at various points of a studied site, which are used to propose a new approach to seismic microzonation (SMZ) that enables the creation of new SMZ maps of strong seismic motion, with due regard for dynamic parameters of recorded transients during weak earthquakes.

  8. Weight factors in diffraction transformation of seismic recordings

    Energy Technology Data Exchange (ETDEWEB)

    Bulatov, M.G.; Lyevyy, N.V.; Telegin, A.N.

    1980-01-01

    In diffraction transformation of seismic recordings made using amplitude regulators, there is a distortion of the dynamics of the result-producing depth log. To eliminate distortions, it is suggested that weight factors be used. A formula is given for computing the factors, and the effectiveness of their use is confirmed using test and production seismic materials.

  9. Effect of seismic activities on ion temperature in the F{sub 2} region of the ionosphere

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, D.K.; Rai, J. [Department of Physics, Indian Institute of Technology, Roorkee (India); Chand, R.; Israil, M. [Department of Earth Sciences, Indian Institute of Technology, Roorkee (India)]. E-mail: ramesh20june@yahoo.co.in

    2006-01-15

    Ionospheric anomalies related to the seismic events have been analyzed in the present paper. The ionospheric ion temperature data recorded by the Retarded Potential Analyzer (RPA) payload aboard the Indian SROSS-C2 satellite are used for the period from January 1995 to December 1996. Earthquake events recorded in the region of interest from United State Geological Survey (USGS) were used to define the ionospheric ion temperature anomalies associated with the earthquake preparation, occurrence and relaxation. Ionospheric ion temperature data were analyzed in such a way that the anomalies due to other phenomena will not be masked over the temperature anomalies due to earthquakes. Ion temperature enhancements in the ionosphere were observed during earthquake events and few pre-post days to the events. The seismogenic vertical electric field propagation up to ionospheric height induces the Joule heating that may cause the ion temperature enhancement. [Spanish] En este articulo se analizan anomalias ionosfericas relacionadas con eventos sismicos. Se utilizaron los datos de temperatura ionosferica registrados por el Analizador Potencial Retrasado (RPA) del satelite hindu SROSS-C2 para el periodo de enero de 1995 a diciembre de 1996. Para definir las anomalias de la temperatura ionica de la ionosfera asociadas con la preparacion, ocurrencia y relajacion de los eventos sismicos se utilizaron los datos de estos eventos registrados por el Estudio Geologico de Estado Unido (USGS) para la region de interes. Los datos de temperatura ionica fueron analizados de manera que las anomalias debidas a otros fenomenos no enmascararan aquellas relacionadas con los eventos sismicos. La propagacion del campo electrico vertical sismogenico hacia la ionosfera induce el calentamiento joulico que podria causar el incremento de la temperatura ionica.

  10. Development of seismic PSA methodology at JAERI

    International Nuclear Information System (INIS)

    Muramatsu, K.; Ebisawa, K.; Matsumoto, K.; Oikawa, T.; Kondo, M.

    1995-01-01

    The Japan Atomic Energy Research Institute (JAERI) is developing a methodology for seismic probabilistic safety assessment (PSA) of nuclear power plants, aiming at providing a set of procedures, computer codes and data suitable for performing seismic PSA in Japan. In order to demonstrate the usefulness of JAERI's methodology and to obtain better understanding on the controlling factors of the results of seismic PSAs, a seismic PSA for a BWR is in progress. In the course of this PSA, various improvements were made on the methodology. In the area of the hazard analysis, the application of the current method to the model plant site is being carried out. In the area of response analysis, the response factor method was modified to consider the non-linear response effect of the building. As for the capacity evaluation of components, since capacity data for PSA in Japan are very scarce, capacities of selected components used in Japan were evaluated. In the systems analysis, the improvement of the SECOM2 code was made to perform importance analysis and sensitivity analysis for the effect of correlation of responses and correlation of capacities. This paper summarizes the recent progress of the seismic PSA research at JAERI with emphasis on the evaluation of component capacity and the methodology improvement of systems reliability analysis. (author)

  11. Nonlinear acoustic/seismic waves in earthquake processes

    International Nuclear Information System (INIS)

    Johnson, Paul A.

    2012-01-01

    Nonlinear dynamics induced by seismic sources and seismic waves are common in Earth. Observations range from seismic strong ground motion (the most damaging aspect of earthquakes), intense near-source effects, and distant nonlinear effects from the source that have important consequences. The distant effects include dynamic earthquake triggering—one of the most fascinating topics in seismology today—which may be elastically nonlinearly driven. Dynamic earthquake triggering is the phenomenon whereby seismic waves generated from one earthquake trigger slip events on a nearby or distant fault. Dynamic triggering may take place at distances thousands of kilometers from the triggering earthquake, and includes triggering of the entire spectrum of slip behaviors currently identified. These include triggered earthquakes and triggered slow, silent-slip during which little seismic energy is radiated. It appears that the elasticity of the fault gouge—the granular material located between the fault blocks—is key to the triggering phenomenon.

  12. Calculating seismic of slabs ITA NNP Garona

    International Nuclear Information System (INIS)

    Ezeberry, J. I.; Guerrero, A.; Gamarra, J.; Beltran, F.

    2014-01-01

    This article describes the methodology that Idom has employed to perform the seismic evaluation of slabs within the ITA project of the NPP Santa Maria de Garona. Seismic calculations that have been conducted include consideration of the effects of the interaction of soil structure as well as the possible take-off containers with respect to slab during the earthquake. Therefore, the main contribution of the work is the study of the coupling of rolling containers with the flexibility of the whole ground-slab For calculations has been used ABAQUS/Explicit program, allowing to solve effectively the nonlinearities listed above using explicit integration algorithms over time. The results of the calculations reflect the importance of jointly analyse the seismic responses of slab and containers. (Author)

  13. Quake warnings, seismic culture

    Science.gov (United States)

    Allen, Richard M.; Cochran, Elizabeth S.; Huggins, Tom; Miles, Scott; Otegui, Diego

    2017-01-01

    Since 1990, nearly one million people have died from the impacts of earthquakes. Reducing those impacts requires building a local seismic culture in which residents are aware of earthquake risks and value efforts to mitigate harm. Such efforts include earthquake early warning (EEW) systems that provide seconds to minutes notice of pending shaking. Recent events in Mexico provide an opportunity to assess performance and perception of an EEW system and highlight areas for further improvement. We have learned that EEW systems, even imperfect ones, can help people prepare for earthquakes and build local seismic culture, both beneficial in reducing earthquake-related losses.

  14. Induced Seismicity Monitoring System

    Science.gov (United States)

    Taylor, S. R.; Jarpe, S.; Harben, P.

    2014-12-01

    There are many seismological aspects associated with monitoring of permanent storage of carbon dioxide (CO2) in geologic formations. Many of these include monitoring underground gas migration through detailed tomographic studies of rock properties, integrity of the cap rock and micro seismicity with time. These types of studies require expensive deployments of surface and borehole sensors in the vicinity of the CO2 injection wells. Another problem that may exist in CO2 sequestration fields is the potential for damaging induced seismicity associated with fluid injection into the geologic reservoir. Seismic hazard monitoring in CO2 sequestration fields requires a seismic network over a spatially larger region possibly having stations in remote settings. Expensive observatory-grade seismic systems are not necessary for seismic hazard deployments or small-scale tomographic studies. Hazard monitoring requires accurate location of induced seismicity to magnitude levels only slightly less than that which can be felt at the surface (e.g. magnitude 1), and the frequencies of interest for tomographic analysis are ~1 Hz and greater. We have developed a seismo/acoustic smart sensor system that can achieve the goals necessary for induced seismicity monitoring in CO2 sequestration fields. The unit is inexpensive, lightweight, easy to deploy, can operate remotely under harsh conditions and features 9 channels of recording (currently 3C 4.5 Hz geophone, MEMS accelerometer and microphone). An on-board processor allows for satellite transmission of parameter data to a processing center. Continuous or event-detected data is kept on two removable flash SD cards of up to 64+ Gbytes each. If available, data can be transmitted via cell phone modem or picked up via site visits. Low-power consumption allows for autonomous operation using only a 10 watt solar panel and a gel-cell battery. The system has been successfully tested for long-term (> 6 months) remote operations over a wide range

  15. Seismic microzonation of Bangalore, India

    Indian Academy of Sciences (India)

    Evaluation of seismic hazards and microzonation of cities enable us to characterize the potential seismic areas which have similar exposures to haz- ards of earthquakes, and these results can be used for designing new structures or retrofitting the existing ones. Study of seismic hazard and preparation of microzonation ...

  16. Simulation of the Basin Effects in the Po Plain During the Emilia-Romagna Seismic Sequence (2012) Using Empirical Green's Functions

    Science.gov (United States)

    Dujardin, Alain; Causse, Mathieu; Courboulex, Françoise; Traversa, Paola

    2016-06-01

    The two main earthquakes that occurred in 2012 (May 20 and 29) in the Reggio-Emiliano region (Northern Italy) were relatively small (Mw 6.1 and Mw 5.9) but they generated unexpected damages in a large area around the epicenter. On some stations, the observed seismic levels exceeded design levels recommended by the EC8 seismic code for buildings and civil engineering works. The ground motions generated by the two mainshocks have specific characteristics: the waveforms are mainly controlled by surface waves generated by the deep sedimentary Po plain, by local site effects and also, on some stations, by non-linear behaviors. In this particular context, we test the ability of an empirical Green's function (EGF) simulation approach to reproduce the recorded seismograms in a large frequency band without any knowledge of the underground medium. We focus on the possibility to reproduce the strong surface waves generated by the basin at distances between 25 and 90 km. We choose to work on the second mainshock of the sequence (Mw 5.9), which occurred on May 29, 2012, because it is better recorded by the seismological networks than the May 20th first mainshock. We use a k-2 kinematic source model to generate a set of 100 slip distributions on the fault plane and choose the recordings of a close-by Mw 3.9 event as EGF. We then generate a set of broad-band seismograms (from 0.2 to 35 Hz) and compare them to the mainshock signals at 15 stations (Seismograms, Fourier spectra, PGA, PGV, duration, Stockwell Transforms) at epicentral distances from 5 to 160 km. We find that the main specific features of the signals are very well reproduced for all the stations within and beyond the basin. Nevertheless, at nearby stations, the PGA values are over-evaluated, which could be explained by the fact that non- linear effects are not taken into account in the simulation process. A better fit was found for a position of the nucleation point to the bottom west of the fault, that suggest a

  17. Original earthquake design basis in light of recent seismic hazard studies

    International Nuclear Information System (INIS)

    Petrovski, D.

    1993-01-01

    For the purpose of conceiving the framework within which efforts have been made in the eastern countries to construct earthquake resistant nuclear power plants, a review of the development and application of the seismic zoning map of USSR is given. The normative values of seismic intensity and acceleration are discussed from the aspect of recent probabilistic seismic hazard studies. To that effect, presented briefly in this paper is the methodology of probabilistic seismic hazard analysis. (author)

  18. Seismic vulnerability of natural gas pipelines

    International Nuclear Information System (INIS)

    Lanzano, Giovanni; Salzano, Ernesto; Santucci de Magistris, Filippo; Fabbrocino, Giovanni

    2013-01-01

    This work deals with the analysis of the interaction of earthquakes with pipelines transporting and distributing natural gas for industrial and civil use. To this aim, a new large data-set of seismic information classified on the basis of selected seismological, geotechnical and structural parameters is presented and analyzed. Particular attention is devoted to continuous pipelines under strong ground shaking, which is the geotechnical effect due to passage of waves in soil. Results are provided in terms of the likelihood of the loss of containment with respect to Peak Ground Velocity (PGV), a seismic intensity parameter which may be easily retrieved either from local authorities and public databases or from site dependent hazard analysis. Fragility functions and seismic intensity threshold values for the failure and for the loss of containment of gas from pipeline systems are also given. The obtained functions can be easily implemented in existing codes and guidelines for industrial risk assessment, land-use planning, and for the design of public distribution network, with specific reference to Natural—Technological interaction (Na-Tech). -- Highlights: • The seismic vulnerability of natural gas pipelines is analyzed. • A collection of data for pipelines damaged by earthquake is given. • Damage states and risk states for pipelines are defined. • Consequence-based fragility formulations for the loss of containment are given • Seismic threshold values for public authority, risk assessment and gas distribution are shown

  19. The seismic analyzer: interpreting and illustrating 2D seismic data.

    Science.gov (United States)

    Patel, Daniel; Giertsen, Christopher; Thurmond, John; Gjelberg, John; Gröller, M Eduard

    2008-01-01

    We present a toolbox for quickly interpreting and illustrating 2D slices of seismic volumetric reflection data. Searching for oil and gas involves creating a structural overview of seismic reflection data to identify hydrocarbon reservoirs. We improve the search of seismic structures by precalculating the horizon structures of the seismic data prior to interpretation. We improve the annotation of seismic structures by applying novel illustrative rendering algorithms tailored to seismic data, such as deformed texturing and line and texture transfer functions. The illustrative rendering results in multi-attribute and scale invariant visualizations where features are represented clearly in both highly zoomed in and zoomed out views. Thumbnail views in combination with interactive appearance control allows for a quick overview of the data before detailed interpretation takes place. These techniques help reduce the work of seismic illustrators and interpreters.

  20. Searching for the effects of the May-June 2012 Emilia seismic sequence (northern Italy: medium-depth deformation structures at the periphery of the epicentral area

    Directory of Open Access Journals (Sweden)

    Lisa Borgatti

    2012-10-01

    Full Text Available In 2012, a seismic sequence occurred in the lowlands of the Emilia-Romagna Region (northern Italy, between the borders of the Modena, Ferrara and Bologna Provinces. It consisted of seven mainshocks (5.9 > Ml > 5 that were recorded between May 20 and 29, 2012 [INGV 2012a] and 2,200 minor earthquakes [INGV 2012b]. An interferometric analysis [Bignami et al. 2012, Salvi et al. 2012, this volume] highlighted three main deformation areas, each of which was 12 km wide (from S to N and 10 km to 20 km long in an ESE-WNW to E-W direction, thus affecting an area of about 600 km2 (Figure 1. Field and aerial geological surveys recorded numerous surficial effects, such as: (i sediment liquefaction [Crespellani et al. 2012]; (ii localized ground fissures resembling surficial faulting [Fioravante and Giretti 2012] (Figure 2; (iii groundwater levels rising up to 400 cm above the local ground level in phreatic wells during the mainshocks (lower values were observed in confined aquifers; and (iv dormancy of previously known sinkholes [Borgatti et al. 2010, Cremonini 2010a, and references therein]. Some of the observed surface phenomena were previously recorded as coseismic effects during the earthquakes of Ferrara (1570 and Argenta (1624 [Boschi et al. 1995, Galli 2000], together with the early rising of the water level of the Po River in the Stellata section. […

  1. Relays undergo seismic tests

    International Nuclear Information System (INIS)

    Burton, J.C.

    1977-01-01

    Utilities are required by the Nuclear Regulatory Commission to document that seismic vibration will not adversely affect critical electrical equipment. Seismic testing should be designed to determine the malfunction level (fragility testing). Input possibilities include a continuous sine, a decaying sine, a sine beat, random vibrations, and combinations of random vibrations and sine beat. The sine beat most accurately simulates a seismic event. Test frequencies have a broad range in order to accommodate a variety of relay types and cabinet mounting. Simulation of motion along three axes offers several options, but is best achieved by three in-phase single-axis vibration machines that are less likely to induce testing fatigue failure. Consensus on what constitutes relay failure favors a maximum two microsecond discontinuity. Performance tests should be conducted for at least two of the following: (1) nonoperating modes, (2) operating modes, or (3) the transition above the two modes, with the monitoring mode documented for all three. Results should specify a capability curve of maximum safe seismic acceleration and a graph plotting acceleration with sine-beat frequency

  2. Mobile seismic exploration

    Energy Technology Data Exchange (ETDEWEB)

    Dräbenstedt, A., E-mail: a.draebenstedt@polytec.de, E-mail: rembe@iei.tu-clausthal.de, E-mail: ulrich.polom@liag-hannover.de; Seyfried, V. [Research & Development, Polytec GmbH, Waldbronn (Germany); Cao, X.; Rembe, C., E-mail: a.draebenstedt@polytec.de, E-mail: rembe@iei.tu-clausthal.de, E-mail: ulrich.polom@liag-hannover.de [Institute of Electrical Information Technology, TU Clausthal, Clausthal-Zellerfeld (Germany); Polom, U., E-mail: a.draebenstedt@polytec.de, E-mail: rembe@iei.tu-clausthal.de, E-mail: ulrich.polom@liag-hannover.de [Leibniz Institute of Applied Geophysics, Hannover (Germany); Pätzold, F.; Hecker, P. [Institute of Flight Guidance, TU Braunschweig, Braunschweig (Germany); Zeller, T. [Clausthaler Umwelttechnik Institut CUTEC, Clausthal-Zellerfeld (Germany)

    2016-06-28

    Laser-Doppler-Vibrometry (LDV) is an established technique to measure vibrations in technical systems with picometer vibration-amplitude resolution. Especially good sensitivity and resolution can be achieved at an infrared wavelength of 1550 nm. High-resolution vibration measurements are possible over more than 100 m distance. This advancement of the LDV technique enables new applications. The detection of seismic waves is an application which has not been investigated so far because seismic waves outside laboratory scales are usually analyzed at low frequencies between approximately 1 Hz and 250 Hz and require velocity resolutions in the range below 1 nm/s/√Hz. Thermal displacements and air turbulence have critical influences to LDV measurements at this low-frequency range leading to noise levels of several 100 nm/√Hz. Commonly seismic waves are measured with highly sensitive inertial sensors (geophones or Micro Electro-Mechanical Sensors (MEMS)). Approaching a laser geophone based on LDV technique is the topic of this paper. We have assembled an actively vibration-isolated optical table in a minivan which provides a hole in its underbody. The laser-beam of an infrared LDV assembled on the optical table impinges the ground below the car through the hole. A reference geophone has detected remaining vibrations on the table. We present the results from the first successful experimental demonstration of contactless detection of seismic waves from a movable vehicle with a LDV as laser geophone.

  3. Nucelar reactor seismic safety analysis techniques

    International Nuclear Information System (INIS)

    Cummings, G.E.; Wells, J.E.; Lewis, L.C.

    1979-04-01

    In order to provide insights into the seismic safety requirements for nuclear power plants, a probabilistic based systems model and computational procedure have been developed. This model and computational procedure will be used to identify where data and modeling uncertainties need to be decreased by studying the effect of these uncertainties on the probability of radioactive release and the probability of failure of various structures, systems, and components. From the estimates of failure and release probabilities and their uncertainties the most sensitive steps in the seismic methodologies can be identified. In addition, the procedure will measure the uncertainty due to random occurrences, e.g. seismic event probabilities, material property variability, etc. The paper discusses the elements of this systems model and computational procedure, the event-tree/fault-tree development, and the statistical techniques to be employed

  4. Reduction of seismic response in breeder plants

    International Nuclear Information System (INIS)

    Tajirian, F.F.; Somes, N.F.; Todeschini, R.A.

    1984-01-01

    Thin-walled vessels to be used in the Nuclear Steam Supply Systems (NSSS) of future LMFBR's will be more sensitive to seismic excitation than their equivalents used in conventional LWR plants. Optimization studies of building arrangement have indicated that embedment of future plants may be one feasible strategy for reducing seismic response. This paper presents the results of a three-dimensional soil-structure interaction analysis using the computer program SASSI. Two types of embedded buildings are considered: full embedment of the nuclear island, and embedment of the reactor cavity alone. A comparison, between the response of the embedded structure with that of a plant supported on the surface, indicates that the seismic response at the reactor vessel support ledge can be lowered by embedment of either the entire nuclear island or the reactor cavity alone. This reduction is larger when the plant is embedded in a softer site due to the increased effect of soil-structure interaction

  5. Seismic response of LMFBR tanks with imperfections

    International Nuclear Information System (INIS)

    Gvildys, J.; Ma, D.C.; Chang, Y.W.

    1985-01-01

    This paper deals with seismic responses of imperfect circular tanks. Physical imperfection due to manufacturing tolerances and numerical imperfection due to finite element spatial discretization are described. Numerical imperfections produced by 4-node and 9-node Lagrangian shell elements are examined. A convergence study is performed in which the number of the shell elements required to capture the dominant ''out-of-roundness'' modes under seismic excitations is determined. The response of a shell with a cos4theta imperfection due to manufacturing tolerances is compared with that of a perfect circular shell to demonstrate the effects of imperfection on the axial stresses of the shell under seismic conditions. 3 refs., 4 figs., 2 tabs

  6. Technical development of seismic imaging prospecting

    International Nuclear Information System (INIS)

    Xu Guilai

    2006-01-01

    Geophysical methods and apparatus for shallow engineering geophysical prospecting and mining related in-roadway geophysical prospecting are important research fields which has been studied for long time, unfortunately, little significant advancement has been made compared with the demand of engineering geology. The seismic imaging method and its corresponding equipment are viewed as the most hopeful choice for 0-50 m depth and are studied in this research systematically. The recording equipment CSA is made and the related in-situ data processing software is also developed. Field application experiment for shallow seismic prospecting has been finished, the results show that the CSA seismic imaging and its application technology are effective and practical for the engineering geophysical prospecting of 0-50 m depth, and can meet the demand of engineering geology investigation. Hence, the geophysical method and equipment, which can meet the demand for 0-50 m depth engineering geology investigation have been formed through this research. (authors)

  7. Permafrost Active Layer Seismic Interferometry Experiment (PALSIE).

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knox, Hunter Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); James, Stephanie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lee, Rebekah [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cole, Chris [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    We present findings from a novel field experiment conducted at Poker Flat Research Range in Fairbanks, Alaska that was designed to monitor changes in active layer thickness in real time. Results are derived primarily from seismic data streaming from seven Nanometric Trillium Posthole seismometers directly buried in the upper section of the permafrost. The data were evaluated using two analysis methods: Horizontal to Vertical Spectral Ratio (HVSR) and ambient noise seismic interferometry. Results from the HVSR conclusively illustrated the method's effectiveness at determining the active layer's thickness with a single station. Investigations with the multi-station method (ambient noise seismic interferometry) are continuing at the University of Florida and have not yet conclusively determined active layer thickness changes. Further work continues with the Bureau of Land Management (BLM) to determine if the ground based measurements can constrain satellite imagery, which provide measurements on a much larger spatial scale.

  8. 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

  9. High Voltage Seismic Generator

    Science.gov (United States)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin

    2015-04-01

    This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes

  10. Romanian seismic network

    International Nuclear Information System (INIS)

    Ionescu, Constantin; Rizescu, Mihaela; Popa, Mihaela; Grigore, Adrian

    2000-01-01

    The research in the field of seismology in Romania is mainly carried out by the National Institute for Earth Physics (NIEP). The NIEP activities are mainly concerned with the fundamental research financed by research contracts from public sources and the maintenance and operation of the Romanian seismic network. A three stage seismic network is now operating under NIEP, designed mainly to monitor the Vrancea seismic region in a magnitude range from microearthquakes to strong events: - network of 18 short-period seismometers (S13); - Teledyne Geotech Instruments (Texas); - network of 7 stations with local digital recording (PCM-5000) on magnetic tape, made up of, S13 geophone (T=2 s) on vertical component and SH1 geophone (T=5 s) on horizontal components; - network of 28 SMA-1 accelerometers and 30 digital accelerometers (Kinemetrics - K2) installed in the free field conditions in the framework of the joint German-Romanian cooperation program (CRC); the K2 instruments cover a magnitude range from 1.4 to 8.0. Since 1994, MLR (Muntele Rosu) station has become part of the GEOFON network and was provided with high performance broad band instruments. At Bucharest and Timisoara data centers, an automated and networked seismological system performs the on-line digital acquisition and processing of the telemetered data. Automatic processing includes discrimination between local and distant seismic events, earthquake location and magnitude computation, and source parameter determination for local earthquakes. The results are rapidly distributed via Internet, to several seismological services in Europe and USA, to be used in the association/confirmation procedures. Plans for new developments of the network include the upgrade from analog to digital telemetry and new stations for monitoring local seismicity. (authors)

  11. 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

  12. Seismic soil-structure interaction of foundations with large piles

    International Nuclear Information System (INIS)

    Zeevaert, L.

    1996-01-01

    In seismic regions with soft soil deposits subjected to ground surface subsidence, there is the necessity to support the weight of constructions on large diameter piles or piers hearing on deep firm strata. To justify the action of these elements working under flexo compression and shear, it is necessary to perform calculations of soil pile interaction from a practical engineering point of view and estimate the order of magnitude of the forces and displacements to which these elements will be subjected during the seismic action assigned to the foundation. In this paper we defined a pier as a large diameter pile constructed on site. Furthermore, in the seismic analysis it is necessary to evaluate the seismic pore water pressure to learn on the effective seismic soil stresses close to the ground surface. (author)

  13. Anomalous density and elastic properties of basalt at high pressure: Reevaluating of the effect of melt fraction on seismic velocity in the Earth's crust and upper mantle

    Science.gov (United States)

    Clark, Alisha N.; Lesher, Charles E.; Jacobsen, Steven D.; Wang, Yanbin

    2016-06-01

    Independent measurements of the volumetric and elastic properties of Columbia River basalt glass were made up to 5.5 GPa by high-pressure X-ray microtomography and GHz-ultrasonic interferometry, respectively. The Columbia River basalt displays P and S wave velocity minima at 4.5 and 5 GPa, respectively, violating Birch's law. These data constrain the pressure dependence of the density and elastic moduli at high pressure, which cannot be modeled through usual equations of state nor determined by stepwise integrating the bulk sound velocity as is common practice. We propose a systematic variation in compression behavior of silicate glasses that is dependent on the degree of polymerization and arises from the flexibility of the aluminosilicate network. This behavior likely persists into the liquid state for basaltic melts resulting in weak pressure dependence for P wave velocities perhaps to depths of the transition zone. Modeling the effect of partial melt on P wave velocity reductions suggests that melt fraction determined by seismic velocity variations may be significantly overestimated in the crust and upper mantle.

  14. UAV Remote Sensing Can Reveal the Effects of Low-Impact Seismic Lines on Surface Morphology, Hydrology, and Methane (CH4) Release in a Boreal Treed Bog

    Science.gov (United States)

    Lovitt, J.; Rahman, M. M.; Saraswati, S.; McDermid, G. J.; Strack, M.; Xu, B.

    2018-03-01

    Peatlands are globally significant stores of soil carbon, where local methane (CH4) emissions are strongly linked to water table position and microtopography. Historically, these factors have been difficult to measure in the field, constraining our capacity to observe local patterns of variability. In this paper, we show how remote sensing surveys conducted from unmanned aerial vehicle (UAV) platforms can be used to map microtopography and depth to water over large areas with good accuracy, paving the way for spatially explicit estimates of CH4 emissions. This approach enabled us to observe—for the first time—the effects of low-impact seismic lines (LIS; petroleum exploration corridors) on surface morphology and CH4 emissions in a treed-bog ecosystem in northern Alberta, Canada. Through compaction, LIS lines were found to flatten the observed range in microtopographic elevation by 46 cm and decrease mean depth to water by 15.4 cm, compared to surrounding undisturbed conditions. These alterations are projected to increase CH4 emissions by 20-120% relative to undisturbed areas in our study area, which translates to a total rise of 0.011-0.027 kg CH4 day-1 per linear kilometer of LIS ( 2 m wide). The 16 km of LIS present at our 61 ha study site were predicted to boost CH4 emissions by 20-70 kg between May and September 2016.

  15. 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

  16. Seismic detection of tornadoes

    Science.gov (United States)

    Tatom, F. B.

    1993-01-01

    Tornadoes represent the most violent of all forms of atmospheric storms, each year resulting in hundreds of millions of dollars in property damage and approximately one hundred fatalities. In recent years, considerable success has been achieved in detecting tornadic storms by means of Doppler radar. However, radar systems cannot determine when a tornado is actually in contact with the ground, expect possibly at extremely close range. At the present time, human observation is the only truly reliable way of knowing that a tornado is actually on the ground. However, considerable evidence exists indicating that a tornado in contact with the ground produces a significant seismic signal. If such signals are generated, the seismic detection and warning of an imminent tornado can become a distinct possibility. 

  17. Seismic analysis - what goal

    International Nuclear Information System (INIS)

    Tagart, S.W.

    1978-01-01

    The seismic analysis of nuclear components is characterized today by extensive engineering computer calculations in order to satisfy both the component standard codes such as ASME III as well as federal regulations and guides. The current nuclear siesmic design procedure has envolved in a fragmented fashion and continues to change its elements as improved technology leads to changing standards and guides. The dominant trend is a monotonic increase in the overall conservation with time causing a similar trend in costs of nuclear power plants. Ironically the improvements in the state of art are feeding a process which is eroding the very incentives that attracted us to nuclear power in the first place. This paper examines the cause of this process and suggests that what is needed is a realistic goal which appropriately addresses the overall uncertainty of the seismic design process. (Auth.)

  18. Seismic capacity of switchgear

    International Nuclear Information System (INIS)

    Bandyopadhyay, K.; Hofmayer, C.; Kassir, M.; Pepper, S.

    1989-01-01

    As part of a component fragility program sponsored by the USNRC, BNL has collected existing information on the seismic capacity of switchgear assemblies from major manufacturers. Existing seismic test data for both low and medium voltage switchgear assemblies have been evaluated and the generic results are presented in this paper. The failure modes are identified and the corresponding generic lower bound capacity levels are established. The test response spectra have been used as a measure of the test vibration input. The results indicate that relays chatter at a very low input level at the base of the switchgear cabinet. This change of state of devices including relays have been observed. Breaker tripping occurs at a higher vibration level. Although the structural failure of internal elements have been noticed, the overall switchgear cabinet structure withstands a high vibration level. 5 refs., 2 figs., 2 tabs

  19. Seismic response analysis for a deeply embedded nuclear power plant

    International Nuclear Information System (INIS)

    Chen, W.W.H.; Chatterjee, M.; Day, S.M.

    1979-01-01

    One of the important aspect of the aseimic design of nuclear power plants is the evaluation of the seismic soil-structure interaction effect due to design earthquakes. The soil-structure interaction effect can initiate rocking and result in different soil motions compared to the free field motions, thus significantly affecting the structural response. Two methods are generally used to solve the seismic soil-structure interaction problems: the direct finite element method (FLUSH) and the substructure or impedance approach. This paper presents the results of the horizontal seismic soil-structure interaction analysis using the impedance aproach and the direct finite element method for a deeply embedded nuclear power plant. (orig.)

  20. Earthquake experience suggests new approach to seismic criteria

    International Nuclear Information System (INIS)

    Knox, R.

    1983-01-01

    Progress in seismic qualification of nuclear power plants as reviewed at the 4th Pacific Basin Nuclear Conference in Vancouver, September 1983, is discussed. The lack of experience of earthquakes in existing nuclear plants can be compensated by the growing experience of actual earthquake effects in conventional power plants and similar installations. A survey of the effects on four power stations, with a total of twenty generating units, in the area strongly shaken by the San Fernando earthquake in California in 1971 is reported. The Canadian approach to seismic qualification, international criteria, Canadian/Korean experience, safety related equipment, the Tadotsu test facility and seismic tests are discussed. (U.K.)

  1. Source of seismic signals

    Energy Technology Data Exchange (ETDEWEB)

    Frankovskii, B.A.; Khor' yakov, K.A.

    1980-08-30

    Patented is a source of seismic signals consisting of a shock generator with a basic low-voltage and auxillary high-voltage stator coils, a capacitive transformer and control switches. To increase the amplitude of signal excitation a condensor battery and auxillary commutator are introduced into the device, which are connected in parallel and serially into the circuit of the main low-voltage stator coil.

  2. Stutter seismic source

    Energy Technology Data Exchange (ETDEWEB)

    Gumma, W. H.; Hughes, D. R.; Zimmerman, N. S.

    1980-08-12

    An improved seismic prospecting system comprising the use of a closely spaced sequence of source initiations at essentially the same location to provide shorter objective-level wavelets than are obtainable with a single pulse. In a preferred form, three dynamite charges are detonated in the same or three closely spaced shot holes to generate a downward traveling wavelet having increased high frequency content and reduced content at a peak frequency determined by initial testing.

  3. Long Period Seismic Waves

    Science.gov (United States)

    1976-08-01

    Geoffsica, TPHM. No. 5 , p. 161. Vargas, Freddy (To he published in 1976) 1 .-DTSCRP1TNACTON DE EVENTO«; NATHDALE«; Y ARTTFTCT ALES. 2.- CALCULO DEL...seismic risk, bv de - fininn relative weiqht of maximum MM intensity at a pivon distance ponulation density, area feolupy and attenuation of intensity wit...Population densitv, area peolopv and attenuation of intensitv with distance, is presented topether with a map anplvinp theorv to Bo- livia. ^«^a

  4. Oklahoma seismic network

    International Nuclear Information System (INIS)

    Luza, K.V.; Lawson, J.E. Jr.; Univ. of Oklahoma, Norman, OK

    1993-07-01

    The US Nuclear Regulatory Commission has established rigorous guidelines that must be adhered to before a permit to construct a nuclear-power plant is granted to an applicant. Local as well as regional seismicity and structural relationships play an integral role in the final design criteria for nuclear power plants. The existing historical record of seismicity is inadequate in a number of areas of the Midcontinent region because of the lack of instrumentation and (or) the sensitivity of the instruments deployed to monitor earthquake events. The Nemaha Uplift/Midcontinent Geophysical Anomaly is one of five principal areas east of the Rocky Mountain front that has a moderately high seismic-risk classification. The Nemaha uplift, which is common to the states of Oklahoma, Kansas, and Nebraska, is approximately 415 miles long and 12-14 miles wide. The Midcontinent Geophysical Anomaly extends southward from Minnesota across Iowa and the southeastern corner of Nebraska and probably terminates in central Kansas. A number of moderate-sized earthquakes--magnitude 5 or greater--have occurred along or west of the Nemaha uplift. The Oklahoma Geological Survey, in cooperation with the geological surveys of Kansas, Nebraska, and Iowa, conducted a 5-year investigation of the seismicity and tectonic relationships of the Nemaha uplift and associated geologic features in the Midcontinent. This investigation was intended to provide data to be used to design nuclear-power plants. However, the information is also being used to design better large-scale structures, such as dams and high-use buildings, and to provide the necessary data to evaluate earthquake-insurance rates in the Midcontinent

  5. Seismic study of soil dynamics at Garner Valley, California

    International Nuclear Information System (INIS)

    Archuleta, R.J.; Seale, S.H.

    1990-01-01

    The Garner Valley downhole array (GVDA) of force-balanced accelerometers was designed to determine the effect that near-surface soil layers have on surface ground motion by measuring in situ seismic waves at various depths. Although there are many laboratory, theoretical and numerical studies that are used to predict the effects that local site geology might have on seismic waves, there are very few direct measurements that can be used to confirm the predictions made by these methods. The effects of local site geology on seismic ground motions are critical for estimating the base motion of structures. The variations in site amplifications at particular periods can range over a factor of 20 or more in comparing amplitude spectra from rock and soil sites, e.g., Mexico City (1985) or San Francisco (1989). The basic phenomenon of nonlinear soil response, and by inference severe attenuation of seismic waves, has rarely been measured although it is commonly observed in laboratory experiments. The basic question is whether or not the local site geology amplifies are attenuates the seismic ground motion. Because the answer depends on the interaction between the local site geology and the amplitude as well as the frequency content of the incoming seismic waves, the in situ measurements must sample the depth variations of the local structure as well as record seismic waves over as wide a range as possible in amplitude and frequency

  6. Seismic contracts and agreements

    International Nuclear Information System (INIS)

    Cooper, N.M.; Krause, V.

    1999-01-01

    Some points to consider regarding management of seismic projects within the Canadian petroleum industry were reviewed. Seismic projects involve the integration of many services. This paper focused on user-provider relationships, the project planning process, competitive bid considerations, the types of agreement used for seismic and their implications, and the impact that certain points of control may have on a company: (1) initial estimate versus actual cost, (2) liability, (3) safety and operational performance, and (4) quality of deliverables. The objective is to drive home the point that in today's environment where companies are forming, merging, or collapsing on a weekly basis , chain of command and accountability are issues that can no longer be dealt with casually. Companies must form business relationships with service providers with a full knowledge of benefits and liabilities of the style of relationship they choose. Diligent and proactive management tends to optimize cost, safety and liability issues, all of which have a bearing on the points of control available to the company

  7. 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

  8. The effects of pressure, temperature, and pore water on velocities in Westerly granite. [for seismic wave propagation

    Science.gov (United States)

    Spencer, J. W., Jr.; Nur, A. M.

    1976-01-01

    A description is presented of an experimental assembly which has been developed to conduct concurrent measurements of compressional and shear wave velocities in rocks at high temperatures and confining pressures and with independent control of the pore pressure. The apparatus was used in studies of the joint effects of temperature, external confining pressure, and internal pore water on sonic velocities in Westerly granite. It was found that at a given temperature, confining pressure has a larger accelerating effect on compressional waves in dry rock, whereas at a given confining pressure, temperature has a larger retarding effect on shear waves.

  9. Vibration analysis and innovative technologies in the seismic preservation of cultural heritage

    International Nuclear Information System (INIS)

    Clemente, P.; Conti, C.; De Stefano, A.

    2015-01-01

    In order to preserve historical buildings and monuments against the effects of earthquakes a detailed analysis is needed to evaluate the characteristics of the seismic input and the dynamic behaviour of structures under seismic actions and to choose the most suitable seismic rehabilitation technique. In this paper the experimental analysis carried out on the Colosseum and the Lateran Obelisk are first shown. Then the application of seismic isolation in historical buildings is discussed and a new structure for the seismic isolation of existing building is presented.

  10. Seismic design criteria and their application to major hazard plant within the United Kingdom

    International Nuclear Information System (INIS)

    Alderson, M.A.H.G.

    1982-12-01

    The nature of seismic motions and the implications are briefly described and the development of seismic design criteria for nuclear power plants in various countries is described including possible future developments. The seismicity of the United Kingdom is briefly reviewed leading to the present position on seismic design criteria for nuclear power plants within the United Kingdom. Damage from past destructive earthquakes is reviewed and the existing codes of practice and standards are described. Finally the effect of earthquakes on major hazard plant is discussed in general terms including the seismic analysis of a typical plant item. (author)

  11. Research items regarding seismic residual risk evaluation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    After learning the Fukushima Dai-ichi NPP severe accidents in 2011, the government investigation committee proposed the effective use of probabilistic safety assessment (PSA), and now it is required to establish new safety rules reflecting the results of probabilistic risk assessment (PRA) and proposed severe accident measures. Since the Seismic Design Guide has been revised on September 19, 2006, JNES has been discussing seismic PRA (Levels 1-3) methods to review licensees' residual risk assessment while preparing seismic PRA models. Meanwhile, new safety standards for light water reactors are to be issued and enforced on July 2013, which require the residual risk of tsunami, in addition to earthquakes, should be lowered as much as possible. The Fukushima accidents raised the problems related to risk assessment, e.g. approaches based on multi-hazard (earthquake and tsunami), multi-unit, multi-site, and equipment's common cause failure. This fiscal year, while performing seismic and/or tsunami PRA to work on these problems, JNES picked up the equipment whose failure greatly contribute to core damage, surveyed accident management measures on those equipment as well as effectiveness to reduce core damage probability. (author)

  12. Seismic isolation of two dimensional periodic foundations

    International Nuclear Information System (INIS)

    Yan, Y.; Mo, Y. L.; Laskar, A.; Cheng, Z.; Shi, Z.; Menq, F.; Tang, Y.

    2014-01-01

    Phononic crystal is now used to control acoustic waves. When the crystal goes to a larger scale, it is called periodic structure. The band gaps of the periodic structure can be reduced to range from 0.5 Hz to 50 Hz. Therefore, the periodic structure has potential applications in seismic wave reflection. In civil engineering, the periodic structure can be served as the foundation of upper structure. This type of foundation consisting of periodic structure is called periodic foundation. When the frequency of seismic waves falls into the band gaps of the periodic foundation, the seismic wave can be blocked. Field experiments of a scaled two dimensional (2D) periodic foundation with an upper structure were conducted to verify the band gap effects. Test results showed the 2D periodic foundation can effectively reduce the response of the upper structure for excitations with frequencies within the frequency band gaps. When the experimental and the finite element analysis results are compared, they agree well with each other, indicating that 2D periodic foundation is a feasible way of reducing seismic vibrations.

  13. Seismic effects on bedrock and underground constructions. A literature survey of damage on constructions; Changes in groundwater levels and flow; Changes in chemistry in groundwater and gases

    International Nuclear Information System (INIS)

    Roeshoff, Kennert.

    1989-06-01

    This report is a literature review of direct and indirect effects of earthquakes on underground constructions as tunnels, caverns and mines. The direct damage will cause vibrations, shaking and displacement, which may lead to partial or total destruction of the underground facility. Damage caused by shaking has been reported in several studies, and several hundreds of events have been reported both from mines and tunnels. These reports are mainly from active earthquake areas. There are very few reports of damage caused by displacements on an existing fault. The damage, which may be severe, is generally concentrated to the vicinity of the fault zone. The report also includes a review of the effects caused by earthquakes on groundwater level, flow, pressure, chemistry and constituents in the ground. Such changes are mainly reported from studies in wells near active faults. The interesting coupling of changes in groundwater characteristics around an underground construction is, unfortunately, very seldom reported. The groundwater level and pressure changes are discussed in Chapter 4. The bases for this part of the review is taken from the Alaska earthquake 1964. Other observations are reported from wells and reservoirs located near existing faults. Changes of the geochemistry in groundwater and soil gases are reviewed in Chapter 4. The mechanisms of seismochemical anomalies are discussed and examples of short and long term monitoring are given from USA, Soviet Union and China. Gases in ground water and soil is reported in Chapter 5. Radon is so far one of the most studied species and its variation in short, medium and long term with seismic activity is rather well understood. Other gases or isotopes that have been studied include helium, carbon dioxide, hydrogen, argon and methane, radium and uranium. The paper also includes same statements for repository design based on the result of the review. (81 refs.)

  14. Seismic fragility capacity of equipment

    International Nuclear Information System (INIS)

    Iijima, Toru; Abe, Hiroshi; Suzuki, Kenichi

    2006-01-01

    Seismic probabilistic safety assessment (PSA) is an available method to evaluate residual risks of nuclear plants that are designed on definitive seismic conditions. From our preliminary seismic PSA analysis, horizontal shaft pumps are important components that have significant influences on the core damage frequency (CDF). An actual horizontal shaft pump and some kinds of elements were tested to evaluate realistic fragility capacities. Our test results showed that the realistic fragility capacity of horizontal shaft pump would be at least four times as high as a current value, 1.6 x 9.8 m/s 2 , used for our seismic PSA. We are going to incorporate the fragility capacity data that were obtained from those tests into our seismic PSA analysis, and we expect that the reliability of seismic PSA should increase. (author)

  15. 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.

  16. Influence of epicentral distance on local seismic response in Kolkata ...

    Indian Academy of Sciences (India)

    Corresponding author. e-mail: wkmohanty@gg.iitkgp.ernet.in. The influence of source and .... specific or site-specific contribution to the ground motion amplitudes ...... Accounting for site effects in probabilistic seismic haz- ard analyses of ...

  17. Protocol for Addressing Induced Seismicity Associated with Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Majer, Ernie [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Nelson, James [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Robertson-Tait, Ann [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Savy, Jean [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Wong, Ivan [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

    2012-01-01

    This Protocol is a living guidance document for geothermal developers, public officials, regulators and the general public that provides a set of general guidelines detailing useful steps to evaluate and manage the effects of induced seismicity related to EGS projects.

  18. Seismic model of the nuclear boiler SPX2

    International Nuclear Information System (INIS)

    Christodoulou, K.

    1982-01-01

    A model of the nuclear boiler SPX2 is proposed in this paper enabling to carry out comparative calculations on the response to seismic effects. The calculations are made in CISE and SEPTEN departments of Electricite de France [fr

  19. Seismic capacity of a reinforced concrete frame structure without seismic detailing and limited ductility seismic design in moderate seismicity

    International Nuclear Information System (INIS)

    Kim, J. K.; Kim, I. H.

    1999-01-01

    A four-story reinforced concrete frame building model is designed for the gravity loads only. Static nonlinear pushover analyses are performed in two orthogonal horizontal directions. The overall capacity curves are converted into ADRS spectra and compared with demand spectra. At several points the deformed shape, moment and shear distribution are calculated. Based on these results limited ductility seismic design concept is proposed as an alternative seismic design approach in moderate seismicity resign

  20. Broadband seismic : case study modeling and data processing

    Science.gov (United States)

    Cahyaningtyas, M. B.; Bahar, A.

    2018-03-01

    Seismic data with wide range of frequency is needed due to its close relation to resolution and the depth of the target. Low frequency provides deeper penetration for the imaging of deep target. In addition, the wider the frequency bandwidth, the sharper the wavelet. Sharp wavelet is responsible for high-resolution imaging and is very helpful to resolve thin bed. As a result, the demand for broadband seismic data is rising and it spurs the technology development of broadband seismic in oil and gas industry. An obstacle that is frequently found on marine seismic data is the existence of ghost that affects the frequency bandwidth contained on the seismic data. Ghost alters bandwidth to bandlimited. To reduce ghost effect and to acquire broadband seismic data, lots of attempts are used, both on the acquisition and on the processing of seismic data. One of the acquisition technique applied is the multi-level streamer, where some streamers are towed on some levels of depth. Multi-level streamer will yield data with varied ghost notch shown on frequency domain. If the ghost notches are not overlapping, the summation of multi-level streamer data will reduce the ghost effect. The result of the multi-level streamer data processing shows that reduction of ghost notch on frequency domain indeed takes place.

  1. Seismic analysis for translational failure of landfills with retaining walls.

    Science.gov (United States)

    Feng, Shi-Jin; Gao, Li-Ya

    2010-11-01

    In the seismic impact zone, seismic force can be a major triggering mechanism for translational failures of landfills. The scope of this paper is to develop a three-part wedge method for seismic analysis of translational failures of landfills with retaining walls. The approximate solution of the factor of safety can be calculated. Unlike previous conventional limit equilibrium methods, the new method is capable of revealing the effects of both the solid waste shear strength and the retaining wall on the translational failures of landfills during earthquake. Parameter studies of the developed method show that the factor of safety decreases with the increase of the seismic coefficient, while it increases quickly with the increase of the minimum friction angle beneath waste mass for various horizontal seismic coefficients. Increasing the minimum friction angle beneath the waste mass appears to be more effective than any other parameters for increasing the factor of safety under the considered condition. Thus, selecting liner materials with higher friction angle will considerably reduce the potential for translational failures of landfills during earthquake. The factor of safety gradually increases with the increase of the height of retaining wall for various horizontal seismic coefficients. A higher retaining wall is beneficial to the seismic stability of the landfill. Simply ignoring the retaining wall will lead to serious underestimation of the factor of safety. Besides, the approximate solution of the yield acceleration coefficient of the landfill is also presented based on the calculated method. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Seismic safety research program plan

    International Nuclear Information System (INIS)

    1987-05-01

    This document presents a plan for seismic research to be performed by the Structural and Seismic Engineering Branch in the Office of Nuclear Regulatory Research. The plan describes the regulatory needs and related research necessary to address the following issues: uncertainties in seismic hazard, earthquakes larger than the design basis, seismic vulnerabilities, shifts in building frequency, piping design, and the adequacy of current criteria and methods. In addition to presenting current and proposed research within the NRC, the plan discusses research sponsored by other domestic and foreign sources

  3. Seismic modelling of shallow coalfields

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, D.C. (University of Calgary, Calgary, Alberta (Canada). Dept. of Geology and Geophysics.)

    1987-01-01

    This study was undertaken in order to determine whether reflection seismic surveys can be used to map stratigraphic and structural detail of shallow Plains-type coal deposits. Two coalfields in central Alberta were used to examine and determine optimum acquisition parameters for reflection seismic surveys in such settings. The study was based on 1-D and 2-D numerical seismic modelling using sonic and density well logs to formulate a layered earth model. Additional objectives were to interpret the reflection seismic data in terms of geologic features in the study area, and to investigate the relationship between vertical resolution and field acquisition geometry. 27 refs., 41 figs.

  4. 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.)

  5. A systematic analysis of directional site effects at stations of the Italian Seismic Network to test the role of local topography

    Science.gov (United States)

    Pischiutta, Marta; Cianfarra, Paola; Salvini, Francesco; Cara, Fabrizio; Vannoli, Paola

    2018-03-01

    Directional site effects observed at seismological stations on pronounced relief are analyzed. We investigate the ground motion properties calculating horizontal-to-vertical spectral ratios and horizontal polarization of both ambient vibrations and earthquake records using broadband seismograms of the Italian Seismic Network. We find that a subset of 47 stations with pronounced relief, results in a significant (>2) directional amplification of the horizontal component, with a well defined, site-specific direction of motion. However, the horizontal spectral response of sites is not uniform, varying from an isolated (resonant) frequency peak to a broadband amplification, interesting frequency bands as large as 1-10 Hz in many cases. Using the 47 selected stations, we have tried to establish a relation between directional amplification and topography geometry in a 2D-vision, when applicable, through a morphological analysis of the Digital Elevation Model using Geographic Information Systems. The procedure computes the parameters that characterize the geometry of topographic irregularities (size and slope), in combination with a principal component analysis that automatically yields the orientation of the elongated ridges. In seeking a relation between directional amplification and the surface morphology, we have found that it is impossible to fit the variety of observations with a resonant topography model as well as to identify common features in the ground motion behavior for stations with similar topography typologies. We conclude that, rather than the shape of the topography, local structural complexities and details of the near-surface structure must play a predominant role in controlling ground motion properties at sites with pronounced relief.

  6. CONCIDERATION OF FOUNDATION AND SEISMIC CONDITIONS OF AREA IN ANALYSIS OF SEISMIC RESISTANCE OF REACTOR COMPARTMENT

    Directory of Open Access Journals (Sweden)

    SEDIN V. L.

    2015-11-01

    Full Text Available Problem statement. Providing of safe exploitation of nuclear power plants, as well as a safety of staff and environment is a very important problem. A distinct feature of this problem is a necessity to provide not only a strength of structures, but also a safe functioning of all systems that control nuclear process. In particular, the influence of earthquake should be considered on constructions of buildings and structures of nuclear and thermal power plant, taking into account soil-structure interaction. According to IAEA’s SSD-9 recommendations, a risk of vibration of soil should be analyzed for each NPP connected with earthquakes soil that means researches, including general, detailed and microseismic zoning of the area works. One of the distinctive features of the considered problem is an evaluation of the seismicity of area and getting the response spectrum on the free surface. Purpose. Determination of seismic resistance of buildings of high category of safety with the example of the reactor compartment of Zaporoghskaya NPP including the soil structure interaction. Conclusion The seismicity assessment of the area and obtaining of response specters on free surface was made during research and analysis of seismic resistance of buildings of high category of safety including the effects of foundation and structures. The method of modeling of the equivalent dynamic characteristics of the base was considered during the research in seismic impacts.

  7. Seismic analysis of large pools

    Energy Technology Data Exchange (ETDEWEB)

    Dong, R.G.; Tokarz, F.J.

    1976-11-17

    Large pools for storing spent, nuclear fuel elements are being proposed to augment present storage capacity. To preserve the ability to isolate portions of these pools, a modularization requirement appears desirable. The purpose of this project was to investigate the effects of modularization on earthquake resistance and to assess the adequacy of current design methods for seismic loads. After determining probable representative pool geometries, three rectangular pool configurations, all 240 x 16 ft and 40 ft deep, were examined. One was unmodularized; two were modularized into 80 x 40 ft cells in one case and 80 x 80 ft cells in the other. Both embedded and above-ground installations for a hard site and embedded installations for an intermediate hard site were studied. It was found that modularization was unfavorable in terms of reducing the total structural load attributable to dynamic effects, principally because one or more cells could be left unfilled. The walls of unfilled cells would be subjected to significantly higher loads than the walls of a filled, unmodularized pool. Generally, embedded installations were preferable to above-ground installations, and the hard site was superior to the intermediate hard site. It was determined that Housner's theory was adequate for calculating hydrodynamic effects on spent fuel storage pools. Current design methods for seismic loads were found to be satisfactory when results from these methods were compared with those from LUSH analyses. As a design method for dynamic soil pressure, we found the Mononobe-Okabe theory, coupled with correction factors as suggested by Seed, to be acceptable. The factors we recommend for spent fuel storage pools are tabulated.

  8. Seismic analysis of large pools

    International Nuclear Information System (INIS)

    Dong, R.G.; Tokarz, F.J.

    1976-01-01

    Large pools for storing spent, nuclear fuel elements are being proposed to augment present storage capacity. To preserve the ability to isolate portions of these pools, a modularization requirement appears desirable. The purpose of this project was to investigate the effects of modularization on earthquake resistance and to assess the adequacy of current design methods for seismic loads. After determining probable representative pool geometries, three rectangular pool configurations, all 240 x 16 ft and 40 ft deep, were examined. One was unmodularized; two were modularized into 80 x 40 ft cells in one case and 80 x 80 ft cells in the other. Both embedded and above-ground installations for a hard site and embedded installations for an intermediate hard site were studied. It was found that modularization was unfavorable in terms of reducing the total structural load attributable to dynamic effects, principally because one or more cells could be left unfilled. The walls of unfilled cells would be subjected to significantly higher loads than the walls of a filled, unmodularized pool. Generally, embedded installations were preferable to above-ground installations, and the hard site was superior to the intermediate hard site. It was determined that Housner's theory was adequate for calculating hydrodynamic effects on spent fuel storage pools. Current design methods for seismic loads were found to be satisfactory when results from these methods were compared with those from LUSH analyses. As a design method for dynamic soil pressure, we found the Mononobe-Okabe theory, coupled with correction factors as suggested by Seed, to be acceptable. The factors we recommend for spent fuel storage pools are tabulated

  9. Seismic stops vs. snubbers, a reliable alternative

    International Nuclear Information System (INIS)

    Cloud, R.L.; Anderson, P.H.; Leung, J.S.M.

    1988-01-01

    The Seismic Stops methodology has been developed to provide a reliable alternative for providing seismic support to nuclear power plant piping. The concept is based on using rigid passive supports with large clearances. These gaps permit unrestrained thermal expansion while limiting excessive seismic displacements. This type of restraint has performed successfully in fossil fueled power plants. A simplified production analysis tool has been developed which evaluates the nonlinear piping response including the effect of the gapped supports. The methodology utilizes the response spectrum approach and has been incorporated into a piping analysis computer program RLCA-GAP. Full scale shake table tests of piping specimens were performed to provide test correlation with the developed methodology. Analyses using RLCA-GAP were in good agreement with test results. A sample piping system was evaluated using the Seismic Stops methodology to replace the existing snubbers with passive gapped supports. To provide further correlation data, the sample system was also evaluated using nonlinear time history analysis. The correlation comparisons showed RLCA-GAP to be a viable methodology and a reliable alternative for snubber optimization and elimination. (orig.)

  10. Seismic-Proof Buildings in Developing Countries

    Directory of Open Access Journals (Sweden)

    Vittoria Laghi

    2017-08-01

    Full Text Available The use of “ductile seismic frames,” whose proper seismic behavior largely depends upon construction details and specific design rules, may do not always lead to effective seismic resistant structures, as dramatically denounced by the famous Chinese artist Ai Weiwei in his artwork Straight. The artwork (96 t of undulating metal bars that were salvaged from schools destroyed by the 2008 Sichuan, China earthquake, where over 5,000 students were killed is a clear denounce against the corruption yielding to shoddy construction methods. The issue of safe constructions against natural hazards appears even more important in developing countries where, in most cases, building structures are realized by non-expert workers, or even by simple “people from the street,” who does not have any technical knowledge on construction techniques and seismic engineering. In this paper, a brief history from the first frame structures to the more efficient wall-based structures is provided within Earthquake Engineering perspectives. The superior structural properties of box-type wall structures with respect to conventional frame structures envisage a change of paradigm from actual “ductility-based” Earthquake Engineering (centered on frame structures toward 100% safe buildings through a “strength-based” design exploiting the use of box-type wall-based structures.

  11. Seismic verification of nuclear plant equipment anchorage

    International Nuclear Information System (INIS)

    Lepiece, M.; Van Vyve, J.

    1991-01-01

    More than 60% of the electrical power of Belgium is generated by seven PWR nuclear power plants. For three of them, the electro-mechanical equipment had to be reassessed after ten years of operation, because the seismic requirements were upgraded from 0.1 g to 0.17 g free field ground acceleration. The seismic requalification of the active equipment was a critical problem as the classical methods were too conservative. The approach based on the use of the past experience on the seismic behavior of nonnuclear equipment, chosen and developed by the SQUG, had to be transposed to the Belgian N.P.P. The decision of the accept-ability of equipment relies heavily on the aseismatic capacity of anchorage. The Electrical Power Research Institute (EPRI) developed the procedure and guideline for the demonstration of the aseismatic adequacy of equipment anchorage in a cost-effective and consistent manner, to support the decision by Seismic Review Team. The field inspection procedure to identify the type of fasteners and detect their possible defects and the verification procedure developed to calculate the aseismatic capacity of equipment anchorage on the strength of fasteners, the aseismatic capacity of anchorage and the comparison of the capacity with the demand are reported. (K.I.)

  12. Induced seismicity associated with enhanced geothermal system

    Energy Technology Data Exchange (ETDEWEB)

    Majer, Ernest; Majer, Ernest L.; Baria, Roy; Stark, Mitch; Oates, Stephen; Bommer, Julian; Smith, Bill; Asanuma, Hiroshi

    2006-09-26

    Enhanced Geothermal Systems (EGS) offer the potential to significantly add to the world energy inventory. As with any development of new technology, some aspects of the technology has been accepted by the general public, but some have not yet been accepted and await further clarification before such acceptance is possible. One of the issues associated with EGS is the role of microseismicity during the creation of the underground reservoir and the subsequent extraction of the energy. The primary objectives of this white paper are to present an up-to-date review of the state of knowledge about induced seismicity during the creation and operation of enhanced geothermal systems, and to point out the gaps in knowledge that if addressed will allow an improved understanding of the mechanisms generating the events as well as serve as a basis to develop successful protocols for monitoring and addressing community issues associated with such induced seismicity. The information was collected though literature searches as well as convening three workshops to gather information from a wide audience. Although microseismicity has been associated with the development of production and injection operations in a variety of geothermal regions, there have been no or few adverse physical effects on the operations or on surrounding communities. Still, there is public concern over the possible amount and magnitude of the seismicity associated with current and future EGS operations. It is pointed out that microseismicity has been successfully dealt with in a variety of non-geothermal as well as geothermal environments. Several case histories are also presented to illustrate a variety of technical and public acceptance issues. It is concluded that EGS Induced seismicity need not pose any threat to the development of geothermal resources if community issues are properly handled. In fact, induced seismicity provides benefits because it can be used as a monitoring tool to understand the

  13. Seismic activity and environment protection in rock burst areas

    International Nuclear Information System (INIS)

    Travnicek, L.; Holecko, J.; Knotek, S.

    1993-01-01

    The significance is pointed out of seismic activity caused by mining activities in rock burst areas of the Ostrava-Karvinna district. The need is emphasized of the monitoring of the seismic activity at the Czech-Poland border as needed by the Two-party international committee for exploitation of coal supplies on the common border. The adverse effect of rock burst on the surface is documented by examples provided by the Polish party. The technique is described of investigating the DPB seismic polygon, allowing to evaluate the adverse impact of rock burst on the environment. (author) 1 fig., 8 refs

  14. Experimental seismic test of fluid coupled co-axial cylinders

    International Nuclear Information System (INIS)

    Chu, M.L.; Brown, S.J.; Lestingi, J.F.

    1979-01-01

    The dynamic response of fluid coupled coaxial cylindrical shells is of interest to the nuclear industry with respect to the seismic design of the reactor vessel and thermal liner. The experiments described present a series of tests which investigate the effect of the annular clearance between the cylinders (gap) on natural frequency, damping, and seismic response of both the inner and outer cylinders. The seismic input is a time history base load to the flexible fluid filled coaxial cylinders. The outer cylinder is elastically supported at both ends while the inner cylinder is supported only at the base (lower) end

  15. Seismic Device UVS 1504, possibilities of its Utilization

    Directory of Open Access Journals (Sweden)

    Leššo Igor

    1996-09-01

    Full Text Available Department of Mining and Geotechnics for many years deals with questions of the technical seismicity. In the paper are given possibilities of utilizing the UVS 1504 device and results obtained from the measurement of seismic effects of blasting as well as others sources of bursts. The measurements showed that this device enables to measure parameters and to evaluate measured data quickly, reliably, and with a very high precision. The device enables evaluating individual time degrees of blasts, determining the law of attenuation of the seismic waves, and precise determination of the maximum charge permissible for futher advance of the blasting in given conditions.

  16. Ensuring seismic safety of Blahutovice nuclear power plant

    International Nuclear Information System (INIS)

    Bartak, V.; David, M.; Hrabe, T.; Simunek, P.

    1989-01-01

    The results are presented of the seismic and geological survey of the Blahutovice nuclear power plant site. The variants are discussed of laying foundations and securing earthquake protection of the reactor building. The calculations made show that all variants are suitable with respect to seismic effects because the acceleration of seismic vibrations at the foundation slab level reaches the maximum intensity of 8deg MSK 64. The variant envisaging that the reactor building should be supported on spring insulators with viscous dampers is considered most advanced. (J.B.). 8 figs., 1 tab

  17. Influence of joint dip angle on seismic behaviors of rock foundation

    International Nuclear Information System (INIS)

    Yang, Lei; Gao, Yang; Jiang, Yujing; Li, Bo; Li Shucai

    2012-01-01

    The seismic response of rock foundation to seismic loads is an important issue to the stability and safety of nuclear power plants. Due to the fact that the discontinuities like joints existing in the rock mass govern principally the deformation and failure behaviors of the rock mass, the influence of discontinuities on the seismic behaviors of rock mass remains as one of the fundamental problems in the safety assessment of nuclear power plants. In this study, the distinct element method (DEM) and finite element method (FEM) were adopted to investigate the seismic responses of rock foundation to a real seismic wave, taking into account the effect of joint dip angle on the deformation and dynamic behaviors of rock foundation. In the DEM simulations, the intact rock has an amplification effect on the amplitudes of seismic waves, while the joints exhibit an attenuation effect on the seismic waves. In the FEM simulations, however, the attenuation effect of joints is not obvious. The dip angle of joints has strong effects on the deformation and dynamic behaviors of rock foundation, in terms that different dip angles lead to obviously different deformation and horizontal stress in the rock foundation when subjected to seismic load. When the dip angle of joints is around 60deg, the seismic velocity, displacement and stress reach the maximums. Therefore, attentions need to be paid on this factor during the seismic design of nuclear power plants. (author)

  18. Guideline for the seismic technical evaluation of replacement items for nuclear power plants

    International Nuclear Information System (INIS)

    Harris, S.P.; Cushing, R.W.; Johnson, H.W.; Abeles, J.M.

    1993-02-01

    Seismic qualification for equipment originally installed in nuclear power plants was typically performed by the original equipment suppliers or manufactures (OES/OEM). Many of the OES/OEM no longer maintain quality assurance programs with adequate controls for supplying nuclear equipment. Utilities themselves must provide reasonable assurance in the continued seismic adequacy of such replacement items. This guideline provides practical, cost-effective techniques which can be used to provide reasonable assurance that replacement items will meet seismic performance requirements necessary to maintain the seismic design basis of commercial nuclear power plants. It also provides a method for determining when a seismic technical evaluation of replacement items (STERI) is required as part of the procurement process for spare and replacement items. Guidance on supplier program requirements necessary to maintain continued seismic adequacy and on documentation of maintaining required seismic adequacy is also included

  19. Preliminary Seismic Response and Fragility Analysis for DACS Cabinet

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Jinho; Kwag, Shinyoung; Lee, Jongmin; Kim, Youngki [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    A DACS cabinet is installed in the main control room. The objective of this paper is to perform seismic analyses and evaluate the preliminary structural integrity and seismic capacity of the DACS cabinet. For this purpose, a 3-D finite element model of the DACS cabinet was developed and its modal analyses are carried out to analyze the dynamic characteristics. The response spectrum analyses and the related safety evaluation are then performed for the DACS cabinet subject to seismic loads. Finally, the seismic margin and seismic fragility of the DACS cabinet are investigated. A seismic analysis and preliminary structural integrity of the DACS cabinet under self weight and SSE load have been evaluated. For this purpose, 3-D finite element models of the DACS cabinet were developed. A modal analysis, response spectrum analysis, and seismic fragility analysis were then performed. From the structural analysis results, the DACS cabinet is below the structural design limit of under SSE 0.3g, and can structurally withstand until less than SSE 3g based on an evaluation of the maximum effective stresses. The HCLPF capacity for the DGRS of the SSE 0.3g is 0.55g. A modal analysis, response spectrum analysis, and seismic fragility analysis were then performed. From the structural analysis results, the DACS cabinet is below the structural design limit of under SSE 0.3g, and can structurally withstand until less than SSE 3g based on an evaluation of the maximum effective stresses. The HCLPF capacity for the DGRS of the SSE 0.3g is 0.55g. Therefore, it is concluded that the DACS cabinet was safely designed in that no damage to the preliminary structural integrity and sufficient seismic margin is expected.

  20. Preliminary Seismic Response and Fragility Analysis for DACS Cabinet

    International Nuclear Information System (INIS)

    Oh, Jinho; Kwag, Shinyoung; Lee, Jongmin; Kim, Youngki

    2013-01-01

    A DACS cabinet is installed in the main control room. The objective of this paper is to perform seismic analyses and evaluate the preliminary structural integrity and seismic capacity of the DACS cabinet. For this purpose, a 3-D finite element model of the DACS cabinet was developed and its modal analyses are carried out to analyze the dynamic characteristics. The response spectrum analyses and the related safety evaluation are then performed for the DACS cabinet subject to seismic loads. Finally, the seismic margin and seismic fragility of the DACS cabinet are investigated. A seismic analysis and preliminary structural integrity of the DACS cabinet under self weight and SSE load have been evaluated. For this purpose, 3-D finite element models of the DACS cabinet were developed. A modal analysis, response spectrum analysis, and seismic fragility analysis were then performed. From the structural analysis results, the DACS cabinet is below the structural design limit of under SSE 0.3g, and can structurally withstand until less than SSE 3g based on an evaluation of the maximum effective stresses. The HCLPF capacity for the DGRS of the SSE 0.3g is 0.55g. A modal analysis, response spectrum analysis, and seismic fragility analysis were then performed. From the structural analysis results, the DACS cabinet is below the structural design limit of under SSE 0.3g, and can structurally withstand until less than SSE 3g based on an evaluation of the maximum effective stresses. The HCLPF capacity for the DGRS of the SSE 0.3g is 0.55g. Therefore, it is concluded that the DACS cabinet was safely designed in that no damage to the preliminary structural integrity and sufficient seismic margin is expected

  1. Seismic Level 2 PSA

    International Nuclear Information System (INIS)

    Dirksen, Gerben; Pellissetti, Manuel; Duncan-Whiteman, Paul

    2014-01-01

    For most external events, the calculation of the core damage frequency (CDF) in Level 1 PSA is sufficient to be able to show that the contribution of the event to the plant risk is negligible. However, it is not sufficient to compare the CDF due to the external event to the total plant CDF; instead the Level 1 PSA result for the event should be compared to the large early release frequency (LERF), or alternatively arguments should be given why the CDF from the external event will not contribute mostly to LERF. For seismic events in particular, it can often not be easily excluded that sequences leading to core damage would not also result in LERF. Since the confinement function is one of the most essential functions for Level 2 PSA, special care must be taken of the containment penetrations. For example systems with containment penetrations that are normally closed during operation or are designed to withstand more than the maximum containment pressure are normally screened out in the Level 2 PSA for the containment isolation function, however the possibility of LOCA in such systems due to an earthquake may nevertheless lead to containment bypass. Additionally, the functionality of passive features may be compromised in case of a beyond design earthquake. In the present paper, we present crucial ingredients of a methodology for a Level 2 seismic PSA. This methodology consists of the following steps: Extension of the seismic equipment list (SEL) to include Level 2 PSA relevant systems (e.g. containment isolation system, features for core melt stabilization, hydrogen mitigation systems), Determination of the systems within the existing SEL with increased demands in case of severe accidents, Determination of essential components for which a dedicated fragility analysis needs to be performed. (author)

  2. Optimal Retrofit Scheme for Highway Network under Seismic Hazards

    Directory of Open Access Journals (Sweden)

    Yongxi Huang

    2014-06-01

    Full Text Available Many older highway bridges in the United States (US are inadequate for seismic loads and could be severely damaged or collapsed in a relatively small earthquake. According to the most recent American Society of Civil Engineers’ infrastructure report card, one-third of the bridges in the US are rated as structurally deficient and many of these structurally deficient bridges are located in seismic zones. To improve this situation, at-risk bridges must be identified and evaluated and effective retrofitting programs should be in place to reduce their seismic vulnerabilities. In this study, a new retrofit strategy decision scheme for highway bridges under seismic hazards is developed and seamlessly integrate the scenario-based seismic analysis of bridges and the traffic network into the proposed optimization modeling framework. A full spectrum of bridge retrofit strategies is considered based on explicit structural assessment for each seismic damage state. As an empirical case study, the proposed retrofit strategy decision scheme is utilized to evaluate the bridge network in one of the active seismic zones in the US, Charleston, South Carolina. The developed modeling framework, on average, will help increase network throughput traffic capacity by 45% with a cost increase of only $15million for the Mw 5.5 event and increase the capacity fourfold with a cost of only $32m for the Mw 7.0 event.

  3. Seismic monitoring of the Creys-Malville plant - Problems raised by the seismic behaviour of a fast breeder reactor

    International Nuclear Information System (INIS)

    Descleve, P.; Barrau, P.

    1988-01-01

    CREYS-MALVILLE reached full power in December 1986 and is presently the largest sodium cooled reactor in operation. Well established procedures of safety evaluation have been used for the design but for a large size reactor special attention must be paid to the effects of seismic disturbances. This paper describes the seismic protection and monitoring system of the plant, the core behaviour which is specific to fast reactors and the test performed to verify the analyses. Finally the seismic impact on the construction can be established as an indication for future plants. (author)

  4. Seismic wave generator

    International Nuclear Information System (INIS)

    Devaure, Bernard.

    1982-01-01

    This invention concerns a device for simulating earth tremors. This device includes a seismic wave generator formed of a cylinder, one end of which is closed by one of the walls of a cell containing a soil, the other end being closed by a wall on which are fixed pyrotechnic devices generating shock waves inside the cylinder. These waves are transmitted from the cylinder to the cell through openings made in the cell wall. This device also includes a mechanical device acting as low-pass filter, located inside the cylinder and close to the cell wall [fr

  5. Mine-induced seismicity at East-Rand proprietary mines

    CSIR Research Space (South Africa)

    Milev, AM

    1995-09-01

    Full Text Available Mining results in seismic activity of varying intensity, from small micro seismic events to larger seismic events, often associated with significant seismic induced damages. This work deals with the understanding of the present seismicity...

  6. Improving fault image by determination of optimum seismic survey parameters using ray-based modeling

    Science.gov (United States)

    Saffarzadeh, Sadegh; Javaherian, Abdolrahim; Hasani, Hossein; Talebi, Mohammad Ali

    2018-06-01

    In complex structures such as faults, salt domes and reefs, specifying the survey parameters is more challenging and critical owing to the complicated wave field behavior involved in such structures. In the petroleum industry, detecting faults has become crucial for reservoir potential where faults can act as traps for hydrocarbon. In this regard, seismic survey modeling is employed to construct a model close to the real structure, and obtain very realistic synthetic seismic data. Seismic modeling software, the velocity model and parameters pre-determined by conventional methods enable a seismic survey designer to run a shot-by-shot virtual survey operation. A reliable velocity model of structures can be constructed by integrating the 2D seismic data, geological reports and the well information. The effects of various survey designs can be investigated by the analysis of illumination maps and flower plots. Also, seismic processing of the synthetic data output can describe the target image using different survey parameters. Therefore, seismic modeling is one of the most economical ways to establish and test the optimum acquisition parameters to obtain the best image when dealing with complex geological structures. The primary objective of this study is to design a proper 3D seismic survey orientation to achieve fault zone structures through ray-tracing seismic modeling. The results prove that a seismic survey designer can enhance the image of fault planes in a seismic section by utilizing the proposed modeling and processing approach.

  7. Recent Seismicity in Texas and Research Design and Progress of the TexNet-CISR Collaboration

    Science.gov (United States)

    Hennings, P.; Savvaidis, A.; Rathje, E.; Olson, J. E.; DeShon, H. R.; Datta-Gupta, A.; Eichhubl, P.; Nicot, J. P.; Kahlor, L. A.

    2017-12-01

    The recent increase in the rate of seismicity in Texas has prompted the establishment of an interdisciplinary, interinstitutional collaboration led by the Texas Bureau of Economic Geology which includes the TexNet Seismic Monitoring and Research project as funded by The State of Texas (roughly 2/3rds of our funding) and the industry-funded Center for Integrated Seismicity Research (CISR) (1/3 of funding). TexNet is monitoring and cataloging seismicity across Texas using a new backbone seismic network, investigating site-specific earthquake sequences by deploying temporary seismic monitoring stations, and conducting reservoir modeling studies. CISR expands TexNet research into the interdisciplinary realm to more thoroughly study the factors that contribute to seismicity, characterize the associated hazard and risk, develop strategies for mitigation and management, and develop methods of effective communication for all stakeholders. The TexNet-CISR research portfolio has 6 themes: seismicity monitoring, seismology, geologic and hydrologic description, geomechanics and reservoir modeling, seismic hazard and risk assessment, and seismic risk social science. Twenty+ specific research projects span and connect these themes. We will provide a synopsis of research progress including recent seismicity trends in Texas; Fort Worth Basin integrated studies including geological modeling and fault characterization, fluid injection data syntheses, and reservoir and geomechanical modeling; regional ground shaking characterization and mapping, infrastructure vulnerability assessment; and social science topics of public perception and information seeking behavior.

  8. Changing theory, changing role of Coriolis effect - The East-West asymmetry of the Wadati-Benioff seismic zones

    Science.gov (United States)

    Scalera, Giancarlo

    2014-05-01

    It is a long history the tale of the recognized asymmetries of the Earth. In 1600 William Gilbert (1544-1603) published De Magnete in which the North and South geomagnetic pole are described. In 1620 Francis Bacon (1561-1628) in the XXVIIth aphorism of the Novum Organum (second part) describes the southern tips of the continents, and many other asymmetries were later described. In 1975 Samuel Warren Carey (1911-2002) stated: Neither north and south, nor east and west are tectonically equivalent. A non exhaustive list of asymmetries of the Earth is: The magnetic polarity; The land-hemisphere and the water-hemisphere; Southern tips of the continents; Larger extension of expanding mid-oceanic ridges on the southern hemisphere; South-eastward trend of younger ages in the long Pacific seafloor volcanic chains; A larger width of the seafloor isochrones bands on the Nazca region; A pear-shaped Earth; etc. It is a few decades that the different slopes of the Wadati-Benioff zones oriented towards the east and west has been enclosed in the list. Under the Americas they have angles of about 30 degrees, while under the Pacific east coasts (Asia, Japan) the angles are steeper (Luyendyk, 1970; Isacks & Barazangi, 1977; and many others). The cause of this difference has been identified in the tidal drag that would cause a global shift of the lithosphere towards west - the so called westward drift (Bostrom, 1971; Stevenson & Turner, 1977; among others). This solution has been many times criticized on the basis of the irrelevance of the tidal forces with respect to viscous friction (Jordan, 1974; Ranalli, 2000; Caputo & Caputo, 2012). Moreover, a simplistic evaluation of the regime of the convective motion in the mantle and of the order of magnitude of the involved forces (viscous, buoyancy, inertial) hastily judges as negligible the role of the Coriolis effect in producing the observed slope differences of the Wadati-Benioff regions. Instead, it is possible to show that changing

  9. Weak localization of seismic waves

    International Nuclear Information System (INIS)

    Larose, E.; Margerin, L.; Tiggelen, B.A. van; Campillo, M.

    2004-01-01

    We report the observation of weak localization of seismic waves in a natural environment. It emerges as a doubling of the seismic energy around the source within a spot of the width of a wavelength, which is several tens of meters in our case. The characteristic time for its onset is the scattering mean-free time that quantifies the internal heterogeneity

  10. DRY TRANSFER FACILITY SEISMIC ANALYSIS

    International Nuclear Information System (INIS)

    EARNEST, S.; KO, H.; DOCKERY, W.; PERNISI, R.

    2004-01-01

    The purpose of this calculation is to perform a dynamic and static analysis on the Dry Transfer Facility, and to determine the response spectra seismic forces for the design basis ground motions. The resulting seismic forces and accelerations will be used in a subsequent calculation to complete preliminary design of the concrete shear walls, diaphragms, and basemat

  11. Seismic Data Gathering and Validation

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-01

    Three recent earthquakes in the last seven years have exceeded their design basis earthquake values (so it is implied that damage to SSC’s should have occurred). These seismic events were recorded at North Anna (August 2011, detailed information provided in [Virginia Electric and Power Company Memo]), Fukushima Daichii and Daini (March 2011 [TEPCO 1]), and Kaswazaki-Kariwa (2007, [TEPCO 2]). However, seismic walk downs at some of these plants indicate that very little damage occurred to safety class systems and components due to the seismic motion. This report presents seismic data gathered for two of the three events mentioned above and recommends a path for using that data for two purposes. One purpose is to determine what margins exist in current industry standard seismic soil-structure interaction (SSI) tools. The second purpose is the use the data to validated seismic site response tools and SSI tools. The gathered data represents free field soil and in-structure acceleration time histories data. Gathered data also includes elastic and dynamic soil properties and structural drawings. Gathering data and comparing with existing models has potential to identify areas of uncertainty that should be removed from current seismic analysis and SPRA approaches. Removing uncertainty (to the extent possible) from SPRA’s will allow NPP owners to make decisions on where to reduce risk. Once a realistic understanding of seismic response is established for a nuclear power plant (NPP) then decisions on needed protective measures, such as SI, can be made.

  12. Seismic re-evaluation of Heavy Water Plant, Kota

    International Nuclear Information System (INIS)

    Parulekar, Y.M.; Reddy, G.R.; Vaze, K.K.; Kushwaha, H.S.

    2003-10-01

    This report deals with seismic re-evaluation of Heavy Water Plant, Kota. Heavy Water Plant, Kota handles considerable amount of H 2 S gas, which is very toxic. During the original design stage as per IS 1893-1966 seismic coefficient for zone-I was zero. Therefore earthquake and its effects were not considered while designing the heavy water plant structures. However as per IS 1893 (1984) the seismic coefficient for zone-I is 0.01 g. Hence seismic re-evaluation of various structures of the heavy water plant is carried out. Analysis of the heavy water plant structures was carried out for self weight, equipment load and earthquake load. Pressure loading was also considered in case of H 2 S storage tanks. Soil structure interaction effect was considered in the analysis. The combined stresses in the structures due to earthquake and dead load were checked with the allowable stresses. (author)

  13. Sloshing of coolant in a seismically isolated reactor

    International Nuclear Information System (INIS)

    Wu, T.S.; Guildys, J.; Seidensticker, R.W.

    1988-01-01

    During a seismic event, the liquid coolant inside the reactor vessel has sloshing motion which is a low-frequency phenomenon. In a reactor system incorporated with seismic isolation, the isolation frequency usually is also very low. There is concern on the potential amplification of sloshing motion of the liquid coolant. This study investigates the effects of seismic isolation on the sloshing of liquid coolant inside the reactor vessel of a liquid metal cooled reactor. Based on a synthetic ground motion whose response spectra envelop those specified by the NRC Regulator Guide 1.60, it is found that the maximum sloshing wave height increases from 18 in. to almost 30 in. when the system is seismically isolated. Since higher sloshing wave may introduce severe impact forces and thermal shocks to the reactor closure and other components within the reactor vessel, adequate design considerations should be made either to suppress the wave height or to reduce the effects caused by high waves

  14. Multivariate Formation Pressure Prediction with Seismic-derived Petrophysical Properties from Prestack AVO inversion and Poststack Seismic Motion Inversion

    Science.gov (United States)

    Yu, H.; Gu, H.

    2017-12-01

    A novel multivariate seismic formation pressure prediction methodology is presented, which incorporates high-resolution seismic velocity data from prestack AVO inversion, and petrophysical data (porosity and shale volume) derived from poststack seismic motion inversion. In contrast to traditional seismic formation prediction methods, the proposed methodology is based on a multivariate pressure prediction model and utilizes a trace-by-trace multivariate regression analysis on seismic-derived petrophysical properties to calibrate model parameters in order to make accurate predictions with higher resolution in both vertical and lateral directions. With prestack time migration velocity as initial velocity model, an AVO inversion was first applied to prestack dataset to obtain high-resolution seismic velocity with higher frequency that is to be used as the velocity input for seismic pressure prediction, and the density dataset to calculate accurate Overburden Pressure (OBP). Seismic Motion Inversion (SMI) is an inversion technique based on Markov Chain Monte Carlo simulation. Both structural variability and similarity of seismic waveform are used to incorporate well log data to characterize the variability of the property to be obtained. In this research, porosity and shale volume are first interpreted on well logs, and then combined with poststack seismic data using SMI to build porosity and shale volume datasets for seismic pressure prediction. A multivariate effective stress model is used to convert velocity, porosity and shale volume datasets to effective stress. After a thorough study of the regional stratigraphic and sedimentary characteristics, a regional normally compacted interval model is built, and then the coefficients in the multivariate prediction model are determined in a trace-by-trace multivariate regression analysis on the petrophysical data. The coefficients are used to convert velocity, porosity and shale volume datasets to effective stress and then

  15. Advances in Rotational Seismic Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Pierson, Robert [Applied Technology Associates, Albuquerque, NM (United States); Laughlin, Darren [Applied Technology Associates, Albuquerque, NM (United States); Brune, Robert [Applied Technology Associates, Albuquerque, NM (United States)

    2016-10-19

    Rotational motion is increasingly understood to be a significant part of seismic wave motion. Rotations can be important in earthquake strong motion and in Induced Seismicity Monitoring. Rotational seismic data can also enable shear selectivity and improve wavefield sampling for vertical geophones in 3D surveys, among other applications. However, sensor technology has been a limiting factor to date. The US Department of Energy (DOE) and Applied Technology Associates (ATA) are funding a multi-year project that is now entering Phase 2 to develop and deploy a new generation of rotational sensors for validation of rotational seismic applications. Initial focus is on induced seismicity monitoring, particularly for Enhanced Geothermal Systems (EGS) with fracturing. The sensors employ Magnetohydrodynamic (MHD) principles with broadband response, improved noise floors, robustness, and repeatability. This paper presents a summary of Phase 1 results and Phase 2 status.

  16. Seismic isolation in New Zealand

    International Nuclear Information System (INIS)

    Skinner, R.I.; Robinson, W.H.; McVerry, G.H.

    1989-01-01

    Bridges, buildings, and industrial equipment can be given increased protection from earthquake damage by limiting the earthquake attack through seismic isolation. A broad summary of the seismic responses of base-isolated structures is of considerable assistance for their preliminary design. Seismic isolation as already used in New Zealand consists of a flexible base or support combined with some form of energy-dissipating device, usually involving the hysteretic working of steel or lead. This paper presents examples of the New Zealand experience, where seismic isolation has been used for 42 bridges, 3 buildings, a tall chimney, and high-voltage capacitor banks. Additional seismic response factors, which may be important for nuclear power plants, are also discussed briefly

  17. Integrated system for seismic evaluations

    International Nuclear Information System (INIS)

    Xu, J.; Philippacopoulos, A.J.; Miller, C.A.; Costantino, C.J.; Graves, H.

    1989-01-01

    This paper describes the various features of the seismic module of the CARES system (computer analysis for rapid evaluation of structures). This system was developed to perform rapid evaluations of structural behavior and capability of nuclear power plant facilities. The CARES is structural in a modular format. Each module performs a specific type of analysis i.e., static or dynamic, linear or nonlinear, etc. This paper describes the features of the seismic module in particular. The development of the seismic modules of the CARES system is based on an approach which incorporates major aspects of seismic analysis currently employed by the industry into an integrated system that allows for carrying out interactively computations of structural response to seismic motions. The code operates on a PC computer system and has multi-graphics capabilities

  18. Field test investigation of high sensitivity fiber optic seismic geophone

    Science.gov (United States)

    Wang, Meng; Min, Li; Zhang, Xiaolei; Zhang, Faxiang; Sun, Zhihui; Li, Shujuan; Wang, Chang; Zhao, Zhong; Hao, Guanghu

    2017-10-01

    Seismic reflection, whose measured signal is the artificial seismic waves ,is the most effective method and widely used in the geophysical prospecting. And this method can be used for exploration of oil, gas and coal. When a seismic wave travelling through the Earth encounters an interface between two materials with different acoustic impedances, some of the wave energy will reflect off the interface and some will refract through the interface. At its most basic, the seismic reflection technique consists of generating seismic waves and measuring the time taken for the waves to travel from the source, reflect off an interface and be detected by an array of geophones at the surface. Compared to traditional geophones such as electric, magnetic, mechanical and gas geophone, optical fiber geophones have many advantages. Optical fiber geophones can achieve sensing and signal transmission simultaneously. With the development of fiber grating sensor technology, fiber bragg grating (FBG) is being applied in seismic exploration and draws more and more attention to its advantage of anti-electromagnetic interference, high sensitivity and insensitivity to meteorological conditions. In this paper, we designed a high sensitivity geophone and tested its sensitivity, based on the theory of FBG sensing. The frequency response range is from 10 Hz to 100 Hz and the acceleration of the fiber optic seismic geophone is over 1000pm/g. sixteen-element fiber optic seismic geophone array system is presented and the field test is performed in Shengli oilfield of China. The field test shows that: (1) the fiber optic seismic geophone has a higher sensitivity than the traditional geophone between 1-100 Hz;(2) The low frequency reflection wave continuity of fiber Bragg grating geophone is better.

  19. Civil Works Seismic Designs

    International Nuclear Information System (INIS)

    1985-12-01

    RFS or Regles Fondamentales de Surete (Basic Safety Rules) applicable to certain types of nuclear facilities lay down requirements with which compliance, for the type of facilities and within the scope of application covered by the RFS, is considered to be equivalent to compliance with technical French regulatory practice. The object of the RFS is to take advantage of standardization in the field of safety, while allowing for technical progress in that field. They are designed to enable the operating utility and contractors to know the rules pertaining to various subjects which are considered to be acceptable by the Service Central de Surete des Installations Nucleaires, or the SCSIN (Central Department for the Safety of Nuclear Facilities). These RFS should make safety analysis easier and lead to better understanding between experts and individuals concerned with the problems of nuclear safety. The SCSIN reserves the right to modify, when considered necessary, any RFS and specify, if need be, the terms under which a modification is deemed retroactive. This rule defines: - the parameters characterizing the design seismic motions - the calculation methods - the mathematical schematization principles on which calculations are based - the use of the seismic response for the structure checking - the content of the documents to be presented

  20. Technical evaluation of seismic qualification of safety-related equipment

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yang Hui; Park, Heong Gee; Park, Yeong Seok [Univ. of Incheon, Incheon (Korea, Republic of)

    1994-04-15

    This study is purposed to evaluate the technical acceptability of the procedures and techniques of seismic qualifications which were performed for the YGN 3 and 4 safety-related equipment.This study is also targeted to suggest a systematized technical procedure guide for the effective performance and review of the seismic qualification, which reflects the most up-to-date licensing requirements and state-of the-art.

  1. A Hammer-Impact, Aluminum, Shear-Wave Seismic Source

    Science.gov (United States)

    Haines, Seth

    2007-01-01

    Near-surface seismic surveys often employ hammer impacts to create seismic energy. Shear-wave surveys using horizontally polarized waves require horizontal hammer impacts against a rigid object (the source) that is coupled to the ground surface. I have designed, built, and tested a source made out of aluminum and equipped with spikes to improve coupling. The source is effective in a variety of settings, and it is relatively simple and inexpensive to build.

  2. Optimization Criteria In Design Of Seismic Isolated Building

    International Nuclear Information System (INIS)

    Clemente, Paolo; Buffarini, Giacomo

    2008-01-01

    Use of new anti-seismic techniques is certainly suitable for buildings of strategic importance and, in general, in the case of very high risk. For ordinary buildings, instead, the cost of base isolation system should be balanced by an equivalent saving in the structure. The comparison criteria have been first defined, then a large numerical investigation has been carried out to analyze the effectiveness and the economic suitability of seismic isolation in concrete buildings

  3. Studies on the seismic buckling design guideline of FBR main vessels. 9. Buckling evaluation under elastic-plastic seismic response

    International Nuclear Information System (INIS)

    Hagiwara, Yutaka; Yamamoto, Kohsuke; Kawamoto, Yoji; Nakagawa, Masaki; Akiyama, Hiroshi

    1998-01-01

    Plastic shear-bending buckling under seismic loadings is one of the major problems in the structural design of FBR main vessels. Pseudo-dynamic and dynamic buckling tests of cylinders were performed in order to study the effects of nonlinear seismic response on buckling strength, ductility, and plastic response reduction. The buckling strength formulae and the rule for ductility factors both derived from static tests were confirmed to be valid for the tests under dynamic loads. The displacement-constant rule for response reduction effect was modified by acceleration amplification factor in order to maintain applicability for various spectral profiles of seismic excitations. The response reduction estimated by the proposed rule was reasonably conservative for all cases of the pseudo-dynamic and the dynamic tests. Finally, a seismic safety assessment rule was proposed for plastic shear-bending buckling of cylinders, which include the proposed response reduction rule. (author)

  4. 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

  5. Seismic Search Engine: A distributed database for mining large scale seismic data

    Science.gov (United States)

    Liu, Y.; Vaidya, S.; Kuzma, H. A.

    2009-12-01

    The International Monitoring System (IMS) of the CTBTO collects terabytes worth of seismic measurements from many receiver stations situated around the earth with the goal of detecting underground nuclear testing events and distinguishing them from other benign, but more common events such as earthquakes and mine blasts. The International Data Center (IDC) processes and analyzes these measurements, as they are collected by the IMS, to summarize event detections in daily bulletins. Thereafter, the data measurements are archived into a large format database. Our proposed Seismic Search Engine (SSE) will facilitate a framework for data exploration of the seismic database as well as the development of seismic data mining algorithms. Analogous to GenBank, the annotated genetic sequence database maintained by NIH, through SSE, we intend to provide public access to seismic data and a set of processing and analysis tools, along with community-generated annotations and statistical models to help interpret the data. SSE will implement queries as user-defined functions composed from standard tools and models. Each query is compiled and executed over the database internally before reporting results back to the user. Since queries are expressed with standard tools and models, users can easily reproduce published results within this framework for peer-review and making metric comparisons. As an illustration, an example query is “what are the best receiver stations in East Asia for detecting events in the Middle East?” Evaluating this query involves listing all receiver stations in East Asia, characterizing known seismic events in that region, and constructing a profile for each receiver station to determine how effective its measurements are at predicting each event. The results of this query can be used to help prioritize how data is collected, identify defective instruments, and guide future sensor placements.

  6. Numerical Modelling of Seismic Slope Stability

    Science.gov (United States)

    Bourdeau, Céline; Havenith, Hans-Balder; Fleurisson, Jean-Alain; Grandjean, Gilles

    Earthquake ground-motions recorded worldwide have shown that many morphological and geological structures (topography, sedimentary basin) are prone to amplify the seismic shaking (San Fernando, 1971 [Davis and West 1973] Irpinia, 1980 [Del Pezzo et al. 1983]). This phenomenon, called site effects, was again recently observed in El Salvador when, on the 13th of January 2001, the country was struck by a M = 7.6 earthquake. Indeed, while horizontal accelerations on a rock site at Berlin, 80 km from the epicentre, did not exceed 0.23 g, they reached 0.6 g at Armenia, 110 km from the epicentre. Armenia is located on a small hill underlaid by a few meters thick pyroclastic deposits. Both the local topography and the presence of surface layers are likely to have caused the observed amplification effects, which are supposed to have contributed to the triggering of some of the hundreds of landslides related to this seismic event (Murphy et al. 2002). In order to better characterize the way site effects may influence the triggering of landslides along slopes, 2D numerical elastic and elasto-plastic models were developed. Various geometrical, geological and seismic conditions were analysed and the dynamic behaviour of the slope under these con- ditions was studied in terms of creation and location of a sliding surface. Preliminary results suggest that the size of modelled slope failures is dependent on site effects.

  7. The Global Detection Capability of the IMS Seismic Network in 2013 Inferred from Ambient Seismic Noise Measurements

    Science.gov (United States)

    Gaebler, P. J.; Ceranna, L.

    2016-12-01

    All nuclear explosions - on the Earth's surface, underground, underwater or in the atmosphere - are banned by the Comprehensive Nuclear-Test-Ban Treaty (CTBT). As part of this treaty, a verification regime was put into place to detect, locate and characterize nuclear explosion testings at any time, by anyone and everywhere on the Earth. The International Monitoring System (IMS) plays a key role in the verification regime of the CTBT. Out of the different monitoring techniques used in the IMS, the seismic waveform approach is the most effective technology for monitoring nuclear underground testing and to identify and characterize potential nuclear events. This study introduces a method of seismic threshold monitoring to assess an upper magnitude limit of a potential seismic event in a certain given geographical region. The method is based on ambient seismic background noise measurements at the individual IMS seismic stations as well as on global distance correction terms for body wave magnitudes, which are calculated using the seismic reflectivity method. From our investigations we conclude that a global detection threshold of around mb 4.0 can be achieved using only stations from the primary seismic network, a clear latitudinal dependence for the detection thresholdcan be observed between northern and southern hemisphere. Including the seismic stations being part of the auxiliary seismic IMS network results in a slight improvement of global detection capability. However, including wave arrivals from distances greater than 120 degrees, mainly PKP-wave arrivals, leads to a significant improvement in average global detection capability. In special this leads to an improvement of the detection threshold on the southern hemisphere. We further investigate the dependence of the detection capability on spatial (latitude and longitude) and temporal (time) parameters, as well as on parameters such as source type and percentage of operational IMS stations.

  8. seismic-py: Reading seismic data with Python

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available The field of seismic exploration of the Earth has changed
    dramatically over the last half a century. The Society of Exploration
    Geophysicists (SEG has worked to create standards to store the vast
    amounts of seismic data in a way that will be portable across computer
    architectures. However, it has been impossible to predict the needs of the
    immense range of seismic data acquisition systems. As a result, vendors have
    had to bend the rules to accommodate the needs of new instruments and
    experiment types. For low level access to seismic data, there is need for a
    standard open source library to allow access to a wide range of vendor data
    files that can handle all of the variations. A new seismic software package,
    seismic-py, provides an infrastructure for creating and managing drivers for
    each particular format. Drivers can be derived from one of the known formats
    and altered to handle any slight variations. Alternatively drivers can be
    developed from scratch for formats that are very different from any previously
    defined format. Python has been the key to making driver development easy
    and efficient to implement. The goal of seismic-py is to be the base system
    that will power a wide range of experimentation with seismic data and at the
    same time provide clear documentation for the historical record of seismic
    data formats.

  9. Seismic response analysis of floating nuclear power plant

    International Nuclear Information System (INIS)

    Hagiwara, Yutaka; Nakamura, Hideharu; Shiojiri, Hiroo

    1988-01-01

    Since Floating Nuclear Power Plants (FNPs) are considered to be isolated from horizontal seismic motion, it is anticipated to reduce seismic load for plant components and buildings on the barge. On the other hand, barge oscillation and sloshing in the closed basin might be excited by earthquakes, because natural periods of those motions correspond to relatively-long period component (between 2 and 20 seconds) of seismic motion. Therefore, it is necessary to evaluate seismic isolation effects and barge oscillation, for the rational design of FNPs. However, there do not exist any reasonable analytical tools which can evaluate seismic response of floating structures in closed basin. The purpose of the present report is to develop a seismic analysis method for FNPs. The proposed method is based on the finite element method, and the formulation includes fluid-structure interaction, water surface wave, buoyancy effect, and non-linear characteristics of mooring system. Response analysis can be executed in both time-domain and frequency-domain. Shaking table tests were conducted to validate the proposed method of analysis. The test results showed significant isolation effect of floating structure, and apparent interaction between the barge and the basin. And 2-D and 3-D frequency domain analyses and the 2-D linear and non-linear time-domain analyses were done and those analyses could simulate the test results well. (author)

  10. Analysis of induced seismicity in geothermal reservoirs – An overview

    Science.gov (United States)

    Zang, Arno; Oye, Volker; Jousset, Philippe; Deichmann, Nicholas; Gritto, Roland; McGarr, Arthur F.; Majer, Ernest; Bruhn, David

    2014-01-01

    In this overview we report results of analysing induced seismicity in geothermal reservoirs in various tectonic settings within the framework of the European Geothermal Engineering Integrating Mitigation of Induced Seismicity in Reservoirs (GEISER) project. In the reconnaissance phase of a field, the subsurface fault mapping, in situ stress and the seismic network are of primary interest in order to help assess the geothermal resource. The hypocentres of the observed seismic events (seismic cloud) are dependent on the design of the installed network, the used velocity model and the applied location technique. During the stimulation phase, the attention is turned to reservoir hydraulics (e.g., fluid pressure, injection volume) and its relation to larger magnitude seismic events, their source characteristics and occurrence in space and time. A change in isotropic components of the full waveform moment tensor is observed for events close to the injection well (tensile character) as compared to events further away from the injection well (shear character). Tensile events coincide with high Gutenberg-Richter b-values and low Brune stress drop values. The stress regime in the reservoir controls the direction of the fracture growth at depth, as indicated by the extent of the seismic cloud detected. Stress magnitudes are important in multiple stimulation of wells, where little or no seismicity is observed until the previous maximum stress level is exceeded (Kaiser Effect). Prior to drilling, obtaining a 3D P-wave (Vp) and S-wave velocity (Vs) model down to reservoir depth is recommended. In the stimulation phase, we recommend to monitor and to locate seismicity with high precision (decametre) in real-time and to perform local 4D tomography for velocity ratio (Vp/Vs). During exploitation, one should use observed and model induced seismicity to forward estimate seismic hazard so that field operators are in a position to adjust well hydraulics (rate and volume of the

  11. Linearized inversion frameworks toward high-resolution seismic imaging

    KAUST Repository

    Aldawood, Ali

    2016-09-01

    Seismic exploration utilizes controlled sources, which emit seismic waves that propagate through the earth subsurface and get reflected off subsurface interfaces and scatterers. The reflected and scattered waves are recorded by recording stations installed along the earth surface or down boreholes. Seismic imaging is a powerful tool to map these reflected and scattered energy back to their subsurface scattering or reflection points. Seismic imaging is conventionally based on the single-scattering assumption, where only energy that bounces once off a subsurface scatterer and recorded by a receiver is projected back to its subsurface position. The internally multiply scattered seismic energy is considered as unwanted noise and is usually suppressed or removed from the recorded data. Conventional seismic imaging techniques yield subsurface images that suffer from low spatial resolution, migration artifacts, and acquisition fingerprint due to the limited acquisition aperture, number of sources and receivers, and bandwidth of the source wavelet. Hydrocarbon traps are becoming more challenging and considerable reserves are trapped in stratigraphic and pinch-out traps, which require highly resolved seismic images to delineate them. This thesis focuses on developing and implementing new advanced cost-effective seismic imaging techniques aiming at enhancing the resolution of the migrated images by exploiting the sparseness of the subsurface reflectivity distribution and utilizing the multiples that are usually neglected when imaging seismic data. I first formulate the seismic imaging problem as a Basis pursuit denoise problem, which I solve using an L1-minimization algorithm to obtain the sparsest migrated image corresponding to the recorded data. Imaging multiples may illuminate subsurface zones, which are not easily illuminated by conventional seismic imaging using primary reflections only. I then develop an L2-norm (i.e. least-squares) inversion technique to image

  12. 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)

  13. Three-dimensional velocity model of the crust of the Bohemian Massif and its effects on seismic tomography of the upper mantle

    Czech Academy of Sciences Publication Activity Database

    Karousová, Hana; Plomerová, Jaroslava; Babuška, Vladislav

    2012-01-01

    Roč. 56, č. 1 (2012), s. 249-267 ISSN 0039-3169 R&D Projects: GA ČR GA205/07/1088; GA AV ČR IAA300120709 Institutional research plan: CEZ:AV0Z30120515 Keywords : crustal structure * seismic methods * Bohemian Massif * teleseismic tomography Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.975, year: 2012

  14. Studies on the Needs of Seismic Base Isolation Concept and its Standardization

    International Nuclear Information System (INIS)

    Lee, Min-Seok; Kim, Jong-Hae

    2015-01-01

    seismic protection of the structures of nuclear facility rather than to solely depend on seismic resistance design alone. This can also bring cost reduction effects both in early construction and in disaster control aftermath. Domestically, various types of devices are used for seismic base isolation systems in bridge projects. The 2005 revised edition of 'the highway bridge design standard' includes seismic base isolation standards under seismic resistance design for the first time in history; however, no efforts have been made to implement this technology in other fields. Therefore, KEPIC is developing seismic base isolation technology standards for the electrical industry

  15. Studies on the Needs of Seismic Base Isolation Concept and its Standardization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min-Seok; Kim, Jong-Hae [Korea Electric Association, Seoul (Korea, Republic of)

    2015-05-15

    seismic protection of the structures of nuclear facility rather than to solely depend on seismic resistance design alone. This can also bring cost reduction effects both in early construction and in disaster control aftermath. Domestically, various types of devices are used for seismic base isolation systems in bridge projects. The 2005 revised edition of 'the highway bridge design standard' includes seismic base isolation standards under seismic resistance design for the first time in history; however, no efforts have been made to implement this technology in other fields. Therefore, KEPIC is developing seismic base isolation technology standards for the electrical industry.

  16. Soil classification for seismic site effect using MASW and ReMi methods: A case study from western Anatolia (Dikili -İzmir)

    Science.gov (United States)

    Karabulut, Savaş

    2018-03-01

    The study area is located in the northern part of Izmir, Western Turkey, prone to an active tectonic extensional regime and includes typical features of sedimentary basins, horst-grabens surrounded by a series of normal and strike-slip faults. In September 1939 the Dikili (Kabakum) earthquake with a magnitude of Mw: 6.6 occurred and after this phenomenon, residents moved from the west of Dikili to the east (i.d. soft sediments to relative to rock area). A proper estimate of the earthquake-related hazard for the area is the main objective of this study. The site effect and soil engineering problems for estimating hazard parameters at the soil surface need to be carefully analyzed for seismic site classification and geo-engineering problems like soil liquefaction, soil settlement, soil bearing capacity and soil amplification. To solve the soil static and dynamic problems, shear-wave velocities have been used in a joint interpretation process; Multichannel Analysis of Surface Waves (MASW) and Refraction Microtremor (ReMi) analyses were conducted on 121 sites with 300 × 300 m grid size in an area of 60 km2. It has been proposed that the probability of an earthquake with a magnitude of Mw: 6 occurring within 10 years is 64%, when considering the Gutenberg-Richter model. This puts the region under an important earthquake risk. The estimated Vs30 values are ≤180 m/s in the central and the northernmost part of the study area are showing an E type soil after the classification of NEHRP, where alluvial deposits are dominant. Vs30 values in the north and central part are between 180 ≤ Vs ≤ 360 m/s suggesting a D type soil. In the southernmost part of the study area where volcanic rocks are widely distributed, Vs30 values range between 360 and 908 m/s, corresponding to a C type and B type soil. The results show that soil liquefaction induced settlement and soil amplification are the most important problems in the south and the northernmost part of the study area, which

  17. Seismic re-evaluation of Kozloduy NPP criteria, methodology, implementation

    International Nuclear Information System (INIS)

    Kostov, M.

    2003-01-01

    The paper describes some features of the methodology applied for seismic upgrading of civil structures at the site of the Kozloduy NPP. The essence of the methodology is the use of as-build data, realistic damping and inelastic reduction factors. As an example of seismic upgrading the analyses of units 3 and 4 are presented. The analyses are showing that for effective seismic upgrading detailed investigations are needed in order to understand the significant response modes of the structures. In the presented case this is the rotation of the attached flexible structures to the stiff reactor building. Based on this an upgrading approach is applied to increase the seismic resistance for the predominant motion. The second significant approach applied is the strengthening of the prefabricated element joints. Although it is very simple it allows use of the available element capacity. (author)

  18. Seismic qualification method of equipment for nuclear power plant

    International Nuclear Information System (INIS)

    Kim, J.S.; Choi, T.H.; Sulaimana, R.A.

    1995-01-01

    Safety related equipment installed in Korean Nuclear Power Plants are required to perform a safety function during and after a seismic event. To accomplish this safety function, they must be seismically qualified in accordance with the intent and requirements of the USNRC Reg. Guide 1.100 Rev. 02 and IEEE Std. 344-1987. This paper defines and summarizes acceptable criteria and procedures, based on the Korean experience, for seismic qualification of purchased equipment to be installed in a nuclear power plant. As such the paper is intended to be a concise reference by equipment designers, architectural engineering company and plant owners in uniform implementation of commitments to nuclear regulatory agencies such as the USNRC or Korea Institute of Nuclear Safety (KINS) relating to adequacy of seismic Category 1 equipment. Thus, the paper provides the methodologies which can be used for qualifying equipment for safely related service in Nuclear Power Plants in a cost effective manner

  19. Analysis of large concrete storage tank under seismic response

    Energy Technology Data Exchange (ETDEWEB)

    Le, Jingyuan; Cui, Hongcheng; He, Qiang; Ju, Jinsan [China Agricultural University, Beijing (China); You, Xiaochuan [Tsinghua University, Beijing (China)

    2015-01-15

    This study adopted the finite element software ABAQUS to trace the dynamic response history of large reinforced concrete storage tank during different seismic excitations. The dynamic characteristics and failure modes of the tank's structure were investigated by considering the rebar's effect. Calculation results show that the large concrete storage tank remains in safe working conditions under a seismic acceleration of 55 cm/s{sup 2}. The joint of the concrete wall and dome begins to crack when seismic acceleration reaches 250 cm/s{sup 2}. As the earthquake continues, cracks spread until the top of the wall completely fails and stops working. The maximum displacement of the concrete tank and seismic acceleration are in proportion. Peak displacement and stress of the tank always appear behind the maximum acceleration.

  20. Reprocessing seismic data: better results below diabase sills

    Energy Technology Data Exchange (ETDEWEB)

    Makler, Marisa [Halliburton Servicos Ltda., Rio de Janeiro, RJ (Brazil); Pellizzon, Marcela

    2008-07-01

    The effect of the diabase sills in the seismic data processing has been studied in the last twenty years. These rocks strongly influence the exploratory activities in a basin, because the diabase disturbs the sign and generates multiple and spherical divergence, increasing the exploratory risk in these areas. In the present work a method of 2D seismic reprocessing will be presented using Prestack Kirchhoff Time Migration in an older seismic data of Solimoes basin. The objective of this paper is to show the high results on the reprocessing seismic data below the diabase sills. The 2D lines processed give relevant improvement of the quality of signal, showing better the faults zones and preserving the geological structures than the older data. (author)

  1. Light Water Reactor Sustainability Program Advanced Seismic Soil Structure Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Bolisetti, Chandrakanth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Coleman, Justin Leigh [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-06-01

    Risk calculations should focus on providing best estimate results, and associated insights, for evaluation and decision-making. Specifically, seismic probabilistic risk assessments (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 has 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). SPRA’s are performed by convolving the seismic hazard (this is the estimate of all likely damaging earthquakes at the site of interest) with the seismic fragility (the conditional probability of failure of a structure, system, or component given the occurrence of earthquake ground motion). In this calculation, there are three main pieces to seismic risk quantification, 1) seismic hazard and nuclear power plants (NPPs) response to the hazard, 2) fragility or capacity of structures, systems and components (SSC), and 3) systems analysis. Two areas where NLSSI effects may be important in SPRA calculations are, 1) when calculating in-structure response at the area of interest, and 2) calculation of seismic fragilities (current fragility calculations assume a lognormal distribution for probability of failure of components). Some important effects when using NLSSI in the SPRA calculation process include, 1) gapping and sliding, 2) inclined seismic waves coupled with gapping and sliding of foundations atop soil, 3) inclined seismic waves coupled with gapping and sliding of deeply embedded structures, 4) soil dilatancy, 5) soil liquefaction, 6) surface waves, 7) buoyancy, 8) concrete cracking and 9) seismic isolation The focus of the research task presented here-in is on implementation of NLSSI into the SPRA calculation process when calculating in-structure response at the area

  2. Seismicity and tectonics of Bangladesh

    International Nuclear Information System (INIS)

    Hossain, K.M.

    1989-05-01

    Northern and eastern Bangladesh and surrounding areas belong to a seismically active zone and are associated with the subduction of the Indian plate. The seismicity and tectonics have been studied in detail and the observations have been correlated to understand the earthquake phenomenon in the region. The morphotectonic behaviour of northern Bangladesh shows that it is deeply related to the movement of the Dauki fault system and relative upliftment of the Shillong plateau. Contemporary seismicity in the Dauki fault system is relatively quiet comparing to that in the Naga-Disang-Haflong thrust belt giving rise to the probability of sudden release of energy being accumulated in the vicinity of the Dauki fault system. This observation corresponds with the predicted average return period of a large earthquake (1897 type) and the possibility of M > 8 earthquake in the vicinity of the Dauki fault within this century should not be ruled out. The seismicity in the folded belt in the east follows the general trend of Arakan-Yoma anticlinorium and represents shallow and low-angled thrust movements in conformity with the field observation. Seismotectonic behaviour in the deep basin part of Bangladesh demonstrates that an intraplate movement in the basement rock has been taking place along the deep-seated faults causing relative upliftment and subsidence in the basin. Bangladesh has been divided into three seismic zones on the basis of morphotectonic and seismic behaviour. Zone-I has been identified as the zone of high seismic risk. (author). 43 refs, 5 figs, 3 tabs

  3. 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.

  4. Integrated system for seismic evaluations

    International Nuclear Information System (INIS)

    Xu, J.; Philippacopoulos, A.J.; Miller, C.A.; Costantino, C.J.; Graves, H.

    1989-01-01

    This paper describes the various features of the Seismic Module of the CARES system (Computer Analysis for Rapid Evaluation of Structures). This system was developed by Brookhaven National Laboratory (BNL) for the US Nuclear Regulatory Commission to perform rapid evaluations of structural behavior and capability of nuclear power plant facilities. The CARES is structured in a modular format. Each module performs a specific type of analysis i.e., static or dynamic, linear or nonlinear, etc. This paper describes the features of the Seismic Module in particular. The development of the Seismic Module of the CARES system is based on an approach which incorporates all major aspects of seismic analysis currently employed by the industry into an integrated system that allows for carrying out interactively computations of structural response to seismic motions. The code operates on a PC computer system and has multi-graphics capabilities. It has been designed with user friendly features and it allows for interactive manipulation of various analysis phases during the seismic design process. The capabilities of the seismic module include (a) generation of artificial time histories compatible with given design ground response spectra, (b) development of Power Spectral Density (PSD) functions associated with the seismic input, (c) deconvolution analysis using vertically propagating shear waves through a given soil profile, and (d) development of in-structure response spectra or corresponding PSD's. It should be pointed out that these types of analyses can also be performed individually by using available computer codes such as FLUSH, SAP, etc. The uniqueness of the CARES, however, lies on its ability to perform all required phases of the seismic analysis in an integrated manner. 5 refs., 6 figs

  5. Canadian seismic agreement

    International Nuclear Information System (INIS)

    Wetmiller, R.J.; Lyons, J.A.; Shannon, W.E.; Munro, P.S.; Thomas, J.T.; Andrew, M.D.; Lamontagne, M.; Wong, C.; Anglin, F.M.; Plouffe, M.; Lapointe, S.P.; Adams, J.; Drysdale, J.A.

    1990-04-01

    This is the twenty-first progress report under the agreement entitled Canadian Seismic Agreement between the US Nuclear Regulatory Commission (NRC) and the Canadian Commercial Corporation. Activities undertaken by the Geophysics Division of the Geological Survey of Canada (GD/GSC) during the period from July 01, 1988 to June 30, 1989 and supported in part by the NRC agreement are described below under four headings; Eastern Canada Telemetred Network and local network developments, Datalab developments, strong motion network developments and earthquake activity. In this time period eastern Canada experienced its largest earthquake in over 50 years. This earthquake, which has been christened the Saguenay earthquake, has provided a wealth of new data pertinent to earthquake engineering studies in eastern North America and is the subject of many continuing studies, which are presently being carried out at GD and elsewhere. 41 refs., 21 figs., 7 tabs

  6. Artificial seismic acceleration

    Science.gov (United States)

    Felzer, Karen R.; Page, Morgan T.; Michael, Andrew J.

    2015-01-01

    In their 2013 paper, Bouchon, Durand, Marsan, Karabulut, 3 and Schmittbuhl (BDMKS) claim to see significant accelerating seismicity before M 6.5 interplate mainshocks, but not before intraplate mainshocks, reflecting a preparatory process before large events. We concur with the finding of BDMKS that their interplate dataset has significantly more fore- shocks than their intraplate dataset; however, we disagree that the foreshocks are predictive of large events in particular. Acceleration in stacked foreshock sequences has been seen before and has been explained by the cascade model, in which earthquakes occasionally trigger aftershocks larger than themselves4. In this model, the time lags between the smaller mainshocks and larger aftershocks follow the inverse power law common to all aftershock sequences, creating an apparent acceleration when stacked (see Supplementary Information).

  7. Seismics - Yesterday and today

    International Nuclear Information System (INIS)

    Frei, W.

    2014-01-01

    This article published in the Swiss Bulletin for Applied Geology takes a look at technical developments in the field of seismological exploration over the past 25 years. In particular, developments in the information technology area are discussed. Increased data-storage capacities and miniaturization of data-capture systems and sensors are examined. In spite of such developments, the quality of the seismological data acquired is quoted as not showing significantly increased quality. Alternatives to vibration-based seismic exploration are discussed. The challenges faced by near-surface seismology are looked at. Computer-based statistical correction of data and improved resolution are discussed, as is hybrid seismology. Examples are quoted and graphically illustrated. A list of relevant literature completes the article

  8. Seismic and Infrasound Location

    Energy Technology Data Exchange (ETDEWEB)

    Arrowsmith, Stephen J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Begnaud, Michael L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-03-19

    This presentation includes slides on Signal Propagation Through the Earth/Atmosphere Varies at Different Scales; 3D Seismic Models: RSTT; Ray Coverage (Pn); Source-Specific Station Corrections (SSSCs); RSTT Conclusions; SALSA3D (SAndia LoS Alamos) Global 3D Earth Model for Travel Time; Comparison of IDC SSSCs to RSTT Predictions; SALSA3D; Validation and Model Comparison; DSS Lines in the Siberian Platform; DSS Line CRA-4 Comparison; Travel Time Δak135; Travel Time Prediction Uncertainty; SALSA3D Conclusions; Infrasound Data Processing: An example event; Infrasound Data Processing: An example event; Infrasound Location; How does BISL work?; BISL: Application to the 2013 DPRK Test; and BISL: Ongoing Research.

  9. Seismic retrofitting of Apsara reactor building

    International Nuclear Information System (INIS)

    Reddy, G.R.; Parulekar, Y.M.; Sharma, A.; Rao, K.N.; Narasimhan, Rajiv; Srinivas, K.; Basha, S.M.; Thomas, V.S.; Soma Kumar, K.

    2006-01-01

    Seismic analysis of Apsara Reactor building was carried out and was found not meeting the current seismic requirements. Due to the building not qualifying for seismic loads, a retrofit scheme using elasto-plastic dampers is proposed. Following activities have been performed in this direction: Carried out detailed seismic analysis of Apsara reactor building structure incorporating proposed seismic retrofit. Demonstrating the capability of the retrofitted structure to with stand the earth quake level for Trombay site as per the current standards by analysis and by model studies. Implementation of seismic retrofit program. This paper presents the details of above aspects related to Seismic analysis and retrofitting of Apsara reactor building. (author)

  10. SEISMIC ANALYSIS FOR PRECLOSURE SAFETY

    Energy Technology Data Exchange (ETDEWEB)

    E.N. Lindner

    2004-12-03

    The purpose of this seismic preclosure safety analysis is to identify the potential seismically-initiated event sequences associated with preclosure operations of the repository at Yucca Mountain and assign appropriate design bases to provide assurance of achieving the performance objectives specified in the Code of Federal Regulations (CFR) 10 CFR Part 63 for radiological consequences. This seismic preclosure safety analysis is performed in support of the License Application for the Yucca Mountain Project. In more detail, this analysis identifies the systems, structures, and components (SSCs) that are subject to seismic design bases. This analysis assigns one of two design basis ground motion (DBGM) levels, DBGM-1 or DBGM-2, to SSCs important to safety (ITS) that are credited in the prevention or mitigation of seismically-initiated event sequences. An application of seismic margins approach is also demonstrated for SSCs assigned to DBGM-2 by showing a high confidence of a low probability of failure at a higher ground acceleration value, termed a beyond-design basis ground motion (BDBGM) level. The objective of this analysis is to meet the performance requirements of 10 CFR 63.111(a) and 10 CFR 63.111(b) for offsite and worker doses. The results of this calculation are used as inputs to the following: (1) A classification analysis of SSCs ITS by identifying potential seismically-initiated failures (loss of safety function) that could lead to undesired consequences; (2) An assignment of either DBGM-1 or DBGM-2 to each SSC ITS credited in the prevention or mitigation of a seismically-initiated event sequence; and (3) A nuclear safety design basis report that will state the seismic design requirements that are credited in this analysis. The present analysis reflects the design information available as of October 2004 and is considered preliminary. The evolving design of the repository will be re-evaluated periodically to ensure that seismic hazards are properly

  11. SEISMIC ANALYSIS FOR PRECLOSURE SAFETY

    International Nuclear Information System (INIS)

    E.N. Lindner

    2004-01-01

    The purpose of this seismic preclosure safety analysis is to identify the potential seismically-initiated event sequences associated with preclosure operations of the repository at Yucca Mountain and assign appropriate design bases to provide assurance of achieving the performance objectives specified in the Code of Federal Regulations (CFR) 10 CFR Part 63 for radiological consequences. This seismic preclosure safety analysis is performed in support of the License Application for the Yucca Mountain Project. In more detail, this analysis identifies the systems, structures, and components (SSCs) that are subject to seismic design bases. This analysis assigns one of two design basis ground motion (DBGM) levels, DBGM-1 or DBGM-2, to SSCs important to safety (ITS) that are credited in the prevention or mitigation of seismically-initiated event sequences. An application of seismic margins approach is also demonstrated for SSCs assigned to DBGM-2 by showing a high confidence of a low probability of failure at a higher ground acceleration value, termed a beyond-design basis ground motion (BDBGM) level. The objective of this analysis is to meet the performance requirements of 10 CFR 63.111(a) and 10 CFR 63.111(b) for offsite and worker doses. The results of this calculation are used as inputs to the following: (1) A classification analysis of SSCs ITS by identifying potential seismically-initiated failures (loss of safety function) that could lead to undesired consequences; (2) An assignment of either DBGM-1 or DBGM-2 to each SSC ITS credited in the prevention or mitigation of a seismically-initiated event sequence; and (3) A nuclear safety design basis report that will state the seismic design requirements that are credited in this analysis. The present analysis reflects the design information available as of October 2004 and is considered preliminary. The evolving design of the repository will be re-evaluated periodically to ensure that seismic hazards are properly

  12. Impacts of seismic activity on long-term repository performance at Yucca Mountain

    International Nuclear Information System (INIS)

    Gauthier, J.H.; Wilson, M.L.; Borns, D.J.; Arnold, B.W.

    1995-01-01

    Several effects of seismic activity on the release of radionuclides from a potential repository at Yucca Mountain are quantified. Future seismic events are predicted using data from the seismic hazard analysis conducted for the Exploratory Studies Facility (ESF). Phenomenological models are developed, including rockfall (thermal-mechanical and seismic) in unbackfilled emplacement drifts, container damage caused by fault displacement within the repository, and flow-path chance caused by changes in strain. Using the composite-porosity flow model (relatively large-scale, regular percolation), seismic events show little effect on total-system releases; using the weeps flow model (episodic pulses of flow in locally saturated fractures), container damage and flow-path changes cause over an order of magnitude increase in releases. In separate calculations using, more realistic representations of faulting, water-table rise caused by seismically induced changes in strain are seen to be higher than previously estimated by others, but not sufficient to reach a potential repository

  13. Seismic gaps and plate tectonics: seismic potential for major boundaries

    Energy Technology Data Exchange (ETDEWEB)

    McCann, W R; Nishenko, S P; Sykes, L R; Krause, J

    1979-01-01

    The theory of plate tectonics provides a basic framework for evaluating the potential for future great earthquakes to occur along major plate boundaries. Along most of the transform and convergent plate boundaries considered in this paper, the majority of seismic slip occurs during large earthquakes, i.e., those of magnitude 7 or greater. The concepts that rupture zones, as delineated by aftershocks, tend to abut rather than overlap, and large events occur in regions with histories of both long-and short-term seismic quiescence are used in this paper to delineate major seismic gaps. The term seismic gap is taken to refer to any region along an active plate boundary that has not experienced a large thrust or strike-slip earthquake for more than 30 years. A region of high seismic potential is a seismic gap that, for historic or tectonic reasons, is considered likely to produce a large shock during the next few decades. The seismic gap technique provides estimates of the location, size of future events and origin time to within a few tens of years at best. The accompanying map summarizes six categories of seismic potential for major plate boundaries in and around the margins of the Pacific Ocean and the Caribbean, South Sandwich and Sunda (Indonesia) regions for the next few decades. These six categories are meant to be interpreted as forecasts of the location and size of future large shocks and should not be considered to be predictions in which a precise estimate of the time of occurrence is specified. The categories of potential assigned here provide a rationale for assigning priorities for instrumentation, for future studies aimed at predicting large earthquakes and for making estimates of tsunami potential.

  14. Progressive Seismic Failure, Seismic Gap, and Great Seismic Risk across the Densely Populated North China Basin

    Science.gov (United States)

    Yin, A.; Yu, X.; Shen, Z.

    2014-12-01

    Although the seismically active North China basin has the most complete written records of pre-instrumentation earthquakes in the world, this information has not been fully utilized for assessing potential earthquake hazards of this densely populated region that hosts ~200 million people. In this study, we use the historical records to document the earthquake migration pattern and the existence of a 180-km seismic gap along the 600-km long right-slip Tangshan-Hejian-Cixian (THC) fault zone that cuts across the North China basin. The newly recognized seismic gap, which is centered at Tianjin with a population of 11 million people and ~120 km from Beijing (22 million people) and Tangshan (7 million people), has not been ruptured in the past 1000 years by M≥6 earthquakes. The seismic migration pattern in the past millennium suggests that the epicenters of major earthquakes have shifted towards this seismic gap along the THC fault, which implies that the 180- km gap could be the site of the next great earthquake with M≈7.6 if it is ruptured by a single event. Alternatively, the seismic gap may be explained by aseismic creeping or seismic strain transfer between active faults.

  15. Post-seismic relaxation from geodetic and seismic data

    Directory of Open Access Journals (Sweden)

    Mikhail V. Rodkin

    2017-01-01

    Full Text Available We have examined the aftershock sequence and the post-seismic deformation process of the Parkfield earthquake (2004, M = 6, California, USA source area using GPS data. This event was chosen because of the possibility of joint analysis of data from the rather dense local GPS network (from SOPAC Internet archive and of the availability of the rather detailed aftershock sequence data (http://www.ncedc.org/ncedc/catalog-search.html. The relaxation process of post-seismic deformation prolongs about the same 400 days as the seismic aftershock process does. Thus, the aftershock process and the relaxation process in deformation could be the different sides of the same process. It should be noted that the ratio of the released seismic energy and of the GPS obtained deformation is quite different for the main shock and for the aftershock stage. The ratio of the released seismic energy to the deformation value decreases essentially for the post-shock process. The similar change in the seismic energy/deformation value ratio is valid in a few other strong earthquakes. Thus, this decrease seems typical of aftershock sequences testifying for decrease of ratio of elastic to inelastic deformation in the process of post-shock relaxation when the source area appears to be mostly fractured after the main shock occurs, but the healing process had no yet sufficient time to develop.

  16. Automated Processing Workflow for Ambient Seismic Recordings

    Science.gov (United States)

    Girard, A. J.; Shragge, J.

    2017-12-01

    Structural imaging using body-wave energy present in ambient seismic data remains a challenging task, largely because these wave modes are commonly much weaker than surface wave energy. In a number of situations body-wave energy has been extracted successfully; however, (nearly) all successful body-wave extraction and imaging approaches have focused on cross-correlation processing. While this is useful for interferometric purposes, it can also lead to the inclusion of unwanted noise events that dominate the resulting stack, leaving body-wave energy overpowered by the coherent noise. Conversely, wave-equation imaging can be applied directly on non-correlated ambient data that has been preprocessed to mitigate unwanted energy (i.e., surface waves, burst-like and electromechanical noise) to enhance body-wave arrivals. Following this approach, though, requires a significant preprocessing effort on often Terabytes of ambient seismic data, which is expensive and requires automation to be a feasible approach. In this work we outline an automated processing workflow designed to optimize body wave energy from an ambient seismic data set acquired on a large-N array at a mine site near Lalor Lake, Manitoba, Canada. We show that processing ambient seismic data in the recording domain, rather than the cross-correlation domain, allows us to mitigate energy that is inappropriate for body-wave imaging. We first develop a method for window selection that automatically identifies and removes data contaminated by coherent high-energy bursts. We then apply time- and frequency-domain debursting techniques to mitigate the effects of remaining strong amplitude and/or monochromatic energy without severely degrading the overall waveforms. After each processing step we implement a QC check to investigate improvements in the convergence rates - and the emergence of reflection events - in the cross-correlation plus stack waveforms over hour-long windows. Overall, the QC analyses suggest that

  17. Seismic Responses of Shot Span Bridge under Three Different Patterns of Earthquake Excitations

    International Nuclear Information System (INIS)

    Zhou Daochuan; Chen Guorong; Lu Yan

    2010-01-01

    This paper presents a study of the influence of three different types of seismic input methods on the longitudinal seismic response of a short, three-span, variable cross-section, reinforced concrete bridge. Research progress of the seismic model is introduced briefly. Finite element model is created for the bridge and time history analysis conducted. Three different types of illustrative excitations are considered: 1) the EI-Centro seismic wave is used as uniform excitations at all bridge supports; 2) fixed apparent wave velocity is used for response analysis of traveling wave excitations on the bridge; 3) conforming to a selected coherency model, the multiple seismic excitation time histories considering spatially variable effects are generated. The contrast study of the response analysis result under the three different seismic excitations is conducted and the influence of different seismic input methods is studied. The comparative analysis of the bridge model shows that the uniform ground motion input can not provide conservative seismic demands-in a number of cases it results in lower response than that predicted by multiple seismic excitations. The result of uniform excitation and traveling wave excitation shows very small difference. Consequently, multiple seismic excitations needs to be applied at the bridge supports for response analysis of short span bridge.

  18. Rock-physics and seismic-inversion based reservoir characterization of the Haynesville Shale

    International Nuclear Information System (INIS)

    Jiang, Meijuan; Spikes, Kyle T

    2016-01-01

    Seismic reservoir characterization of unconventional gas shales is challenging due to their heterogeneity and anisotropy. Rock properties of unconventional gas shales such as porosity, pore-shape distribution, and composition are important for interpreting seismic data amplitude variations in order to locate optimal drilling locations. The presented seismic reservoir characterization procedure applied a grid-search algorithm to estimate the composition, pore-shape distribution, and porosity at the seismic scale from the seismically inverted impedances and a rock-physics model, using the Haynesville Shale as a case study. All the proposed rock properties affected the seismic velocities, and the combined effects of these rock properties on the seismic amplitude were investigated simultaneously. The P- and S-impedances correlated negatively with porosity, and the V _P/V _S correlated positively with clay fraction and negatively with the pore-shape distribution and quartz fraction. The reliability of these estimated rock properties at the seismic scale was verified through comparisons between two sets of elastic properties: one coming from inverted impedances, which were obtained from simultaneous inversion of prestack seismic data, and one derived from these estimated rock properties. The differences between the two sets of elastic properties were less than a few percent, verifying the feasibility of the presented seismic reservoir characterization. (paper)

  19. Installation of a very broad band borehole seismic station in Ferrara (Emilia)

    OpenAIRE

    Pesaresi, Damiano; Dall'Olio, Lorella; Rovelli, Antonio; Romanelli, Marco; Barnaba, Carla; Abu Zeid, Nasser

    2012-01-01

    The Istituto Nazionale di Geofisica e Vulcanologia (INGV) is the Italian agency devoted to monitor in real time the seismicity on the Italian territory. The seismicity in Italy is of course variable in time and space, being also very much dependant on local noise conditions. Specifically, monitoring seismicity in an alluvial basin like the Po one is a challenge, due to consistent site effects induced by soft alluvial deposits and bad coupling with the deep bedrock (Steidl et al., 1996). This...

  20. Comparison of Omega-2 and Omega-3 calibration explosions basing on regional seismic data

    International Nuclear Information System (INIS)

    Mikhajlova, N.N.; Sokolova, I.N.

    2001-01-01

    Comparison of different parameters of seismic records of Omega-2 and Omega-3 calibration explosions was performed. It was shown that despite the equal charge the level of seismic oscillations was lower during the Omega-3 explosion than during Omega-2. Spectral composition, polarization of oscillations, wave picture is identical at a given station for both explosions. Assumptions were made on the reason of such difference in seismic effect. (author)

  1. Seismic fragility analysis of buried steel piping at P, L, and K reactors

    International Nuclear Information System (INIS)

    Wingo, H.E.

    1989-10-01

    Analysis of seismic strength of buried cooling water piping in reactor areas is necessary to evaluate the risk of reactor operation because seismic events could damage these buried pipes and cause loss of coolant accidents. This report documents analysis of the ability of this piping to withstand the combined effects of the propagation of seismic waves, the possibility that the piping may not behave in a completely ductile fashion, and the distortions caused by relative displacements of structures connected to the piping

  2. Seismic analysis of a large LMFBR with fluid-structure interactions

    International Nuclear Information System (INIS)

    Ma, D.C.

    1985-01-01

    The seismic analysis of a large LMFBR with many internal components and structures is presented. Both vertical and horizontal seismic excitations are considered. The important hydrodynamic phenomena such as fluid-structure interaction, sloshing, fluid coupling and fluid inertia effects are included in the analysis. The results of this study are discussed in detail. Information which is useful to the design of future reactions under seismic conditions is also given. 4 refs., 12 figs

  3. Spots of Seismic Danger Extracted by Properties of Low-Frequency Seismic Noise

    Science.gov (United States)

    Lyubushin, Alexey

    2013-04-01

    A new method of seismic danger estimate is presented which is based on using properties of low-frequency seismic noise from broadband networks. Two statistics of noise waveforms are considered: multi-fractal singularity spectrum support width D and minimum normalized entropy En of squared orthogonal wavelet coefficients. The maps of D and En are plotted in the moving time window. Let us call the regions extracted by low values of D and high values of En as "spots of seismic danger" - SSD. Mean values of D and En are strongly anti-correlated - that is why statistics D and En extract the same SSD. Nevertheless their mutual considering is expedient because these parameters are based on different approaches. The physical mechanism which underlies the method is consolidation of small blocks of the Earth's crust into the large one before the strong earthquake. This effect has a consequence that seismic noise does not include spikes which are connected with mutual movements of small blocks. The absence of irregular spikes in the noise follows the decreasing of D and increasing of entropy En. The stability in space and size of the SSD provides estimates of the place and energy of the probable future earthquake. The increasing or decreasing of SSD size and minimum or maximum values of D and En within SSD allows estimate the trend of seismic danger. The method is illustrating by the analysis of seismic noise from broadband seismic network F-net in Japan [1-5]. Statistically significant decreasing of D allowed a hypothesis about approaching Japan to a future seismic catastrophe to be formulated at the middle of 2008. The peculiarities of correlation coefficient estimate within 1 year time window between median values of D and generalized Hurst exponent allowed to make a decision that starting from July of 2010 Japan come to the state of waiting strong earthquake [3]. The method extracted a huge SSD near Japan which includes the region of future Tohoku mega-earthquake and the

  4. Seismic link at plate boundary

    Indian Academy of Sciences (India)

    process constrain the seismic hazard assessment. Some frequent issues .... to obtain information on the causality between .... 2004), and low frequency deep triggering. (Miyazawa .... can trigger shallow thrust fault earthquakes; Science 306.

  5. Worldwide Marine Seismic Reflection Profiles

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NGDC maintains a large volume of both Analog and Digital seismic reflection data. Currently only a limited number of lines are available online. Digital data include...

  6. Seismic surveys test on Innerhytta Pingo, Adventdalen, Svalbard Islands

    Science.gov (United States)

    Boaga, Jacopo; Rossi, Giuliana; Petronio, Lorenzo; Accaino, Flavio; Romeo, Roberto; Wheeler, Walter

    2015-04-01

    We present the preliminary results of an experimental full-wave seismic survey test conducted on the Innnerhytta a Pingo, located in the Adventdalen, Svalbard Islands, Norway. Several seismic surveys were adopted in order to study a Pingo inner structure, from classical reflection/refraction arrays to seismic tomography and surface waves analysis. The aim of the project IMPERVIA, funded by Italian PNRA, was the evaluation of the permafrost characteristics beneath this open-system Pingo by the use of seismic investigation, evaluating the best practice in terms of logistic deployment. The survey was done in April-May 2014: we collected 3 seismic lines with different spacing between receivers (from 2.5m to 5m), for a total length of more than 1 km. We collected data with different vertical geophones (with natural frequency of 4.5 Hz and 14 Hz) as well as with a seismic snow-streamer. We tested different seismic sources (hammer, seismic gun, fire crackers and heavy weight drop), and we verified accurately geophone coupling in order to evaluate the different responses. In such peculiar conditions we noted as fire-crackers allow the best signal to noise ratio for refraction/reflection surveys. To ensure the best geophones coupling with the frozen soil, we dug snow pits, to remove the snow-cover effect. On the other hand, for the surface wave methods, the very high velocity of the permafrost strongly limits the generation of long wavelengths both with these explosive sources as with the common sledgehammer. The only source capable of generating low frequencies was a heavy drop weight system, which allows to analyze surface wave dispersion below 10 Hz. Preliminary data analysis results evidence marked velocity inversions and strong velocity contrasts in depth. The combined use of surface and body waves highlights the presence of a heterogeneous soil deposit level beneath a thick layer of permafrost. This is the level that hosts the water circulation from depth controlling

  7. Overview of seismic resistant design of Indian Nuclear Power Plants

    International Nuclear Information System (INIS)

    Sharma, G.K.; Hawaldar, R.V.K.P.; Vinod Kumar

    2007-01-01

    Safe operation of a Nuclear Power Plant (NPP) is of utmost importance. NPPs consist of various Structure, System and Equipment (SS and E) that are designed to resist the forces generated due to a natural phenomenon like earthquake. An earthquake causes severe oscillatory ground motion of short duration. Seismic resistant design of SS and E calls for evaluation of effect of severe ground shaking for assuring the structural integrity and operability during and after the occurre