Bibliografías temáticas / S-wave velocity

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Literatura académica sobre el tema "S-wave velocity"

Autor: Grafiati
Publicado: 4 de junio de 2021
Última modificación: 1 de abril de 2023

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Artículos de revistas sobre el tema "S-wave velocity"

1

Valentina Socco, Laura y Cesare Comina. "Time-average velocity estimation through surface-wave analysis: Part 2 — P-wave velocity". GEOPHYSICS 82, n.º 3 (1 de mayo de 2017): U61—U73. http://dx.doi.org/10.1190/geo2016-0368.1.

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Surface waves (SWs) in seismic records can be used to extract local dispersion curves (DCs) along a seismic line. These curves can be used to estimate near-surface S-wave velocity models. If the velocity models are used to compute S-wave static corrections, the required information consists of S-wave time-average velocities that define the one-way time for a given datum plan depth. However, given the wider use of P-wave reflection seismic with respect to S-wave surveys, the estimate of P-wave time-average velocity would be more useful. We therefore focus on the possibility of also extracting time-average P-wave velocity models from SW dispersion data. We start from a known 1D S-wave velocity model along the line, with its relevant DC, and we estimate a wavelength/depth relationship for SWs. We found that this relationship is sensitive to Poisson’s ratio, and we develop a simple method for estimating an “apparent” Poisson’s ratio profile, defined as the Poisson’s ratio value that relates the time-average S-wave velocity to the time-average P-wave velocity. Hence, we transform the time-average S-wave velocity models estimated from the DCs into the time-average P-wave velocity models along the seismic line. We tested the method on synthetic and field data and found that it is possible to retrieve time-average P-wave velocity models with uncertainties mostly less than 10% in laterally varying sites and one-way traveltime for P-waves with less than 5 ms uncertainty with respect to P-wave tomography data. To our knowledge, this is the first method for reliable estimation of P-wave velocity from SW data without any a priori information or additional data.
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2

Chen, S. T. "Shear‐wave logging with dipole sources". GEOPHYSICS 53, n.º 5 (mayo de 1988): 659–67. http://dx.doi.org/10.1190/1.1442500.

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Laboratory measurements have verified a novel technique for direct shear‐wave logging in hard and soft formations with a dipole source, as recently suggested in theoretical studies. Conventional monopole logging tools are not capable of measuring shear waves directly. In particular, no S waves are recorded in a soft formation with a conventional monopole sonic tool because there are no critically refracted S rays when the S-wave velocity of the rock is less than the acoustic velocity of the borehole fluid. The present studies were conducted in the laboratory with scale models representative of sonic logging conditions in the field. We have used a concrete model to represent hard formations and a plastic model to simulate a soft formation. The dipole source, operating at frequencies lower than those conventionally used in logging, substantially suppressed the P wave and excited a wave train whose first arrival traveled at the S-wave velocity. As a result, one can use a dipole source to log S-wave velocity directly on‐line by picking the first arrival of the full wave train, in a process similar to that used in conventional P-wave logging. Laboratory experiments with a conventional monopole source in a soft formation did not produce S waves. However, the S-wave velocity was accurately estimated by using Biot’s theory, which required measuring the Stoneley‐wave velocity and knowing other borehole parameters.
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3

Steiner, Brian, Erik H. Saenger y Stefan M. Schmalholz. "Time-reverse imaging with limited S-wave velocity model information". GEOPHYSICS 76, n.º 5 (septiembre de 2011): MA33—MA40. http://dx.doi.org/10.1190/geo2010-0303.1.

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Time-reverse imaging is a wave propagation algorithm for locating sources. Signals recorded by synchronized receivers are reversed in time and propagated back to the source location by elastic wavefield extrapolation. Elastic wavefield extrapolation requires a P-wave as well as an S-wave velocity model. The velocity models available from standard reflection seismic methods are usually restricted to only P-waves. In this study, we use synthetically produced time signals to investigate the accuracy of seismic source localization by means of time-reverse imaging with the correct P-wave and a perturbed S-wave velocity model. The studies reveal that perturbed S-wave velocity models strongly influence the intensity and position of the focus. Imaging the results with the individual maximum energy density for both body wave types instead of mixed modes allows individual analysis of the two body waves. P-wave energy density images render stable focuses in case of a correct P-wave and incorrect S-wave velocity model. Thus, P-wave energy density seems to be a more suitable imaging condition in case of a high degree of uncertainty in the S-wave velocity model.
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4

Li, Lun y Yuanyuan V. Fu. "Surface-Wave Tomography of Eastern and Central Tibet from Two-Plane-Wave Inversion: Rayleigh-Wave and Love-Wave Phase Velocity Maps". Bulletin of the Seismological Society of America 110, n.º 3 (17 de marzo de 2020): 1359–71. http://dx.doi.org/10.1785/0120190199.

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ABSTRACT An understanding of mantle dynamics occurring beneath the Tibetan plateau requires a detailed image of its seismic velocity and anisotropic structure. Surface waves at long periods (>50 s) could provide such critical information. Though Rayleigh-wave phase velocity maps have been constructed in the Tibetan regions using ambient-noise tomography (ANT) and regional earthquake surface-wave tomography, Love-wave phase velocity maps, especially those at longer periods (>50 s), are rare. In this study, two-plane-wave teleseismic surface-wave tomography is applied to develop 2D Rayleigh-wave and Love-wave phase velocity maps at periods between 20 and 143 s across eastern and central Tibet and its surroundings using four temporary broadband seismic experiments. These phase velocity maps share similar patterns and show high consistency with those previously obtained from ANT at overlapping periods (20–50 s), whereas our phase velocity maps carry useful information at longer periods (50–143 s). Prominent slow velocity is imaged at periods of 20–143 s beneath the interior of the Tibetan plateau (i.e., the Songpan–Ganzi terrane, the Qiangtang terrane, and the Lhasa terrane), implying the existence of thick Tibetan crust along with warm and weak Tibetan lithosphere. In contrast, the dispersal of fast velocity anomalies coincides with mechanically strong, cold tectonic blocks, such as the Sichuan basin and the Qaidam basin. These phase velocity maps could be used to construct 3D shear-wave velocity and radial seismic anisotropy models of the crust and upper mantle down to 250 km across the eastern and central Tibetan plateau.
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5

Tang, Huai-Gu, Bing-Shou He y Hai-Bo Mou. "P- and S-wave energy flux density vectors". GEOPHYSICS 81, n.º 6 (noviembre de 2016): T357—T368. http://dx.doi.org/10.1190/geo2016-0245.1.

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The conventional energy flux density vector indicates the propagation direction of mixed P- and S-wave wavefields, which means when a wavefront of P-wave encounters a wavefront of S-wave with different propagation directions, the vectors cannot indicate both directions accurately. To avoid inaccuracies caused by superposition of P- and S-waves in a conventional energy flux density vector, P- and S-wave energy flux density vectors should be calculated separately. Because the conventional energy flux density vector is obtained by multiplying the stress tensor by the particle-velocity vector, the common way to calculate P- and S-wave energy flux density vectors is to decompose the stress tensor and particle-velocity vector into the P- and S-wave parts before multiplication. However, we have found that the P-wave still interfere with the S-wave energy flux density vector calculated by this method. Therefore, we have developed a new method to calculate P- and S-wave energy flux density vectors based on a set of new equations but not velocity-stress equations. First, we decompose elastic wavefield by the set of equations to obtain the P- and S-wave particle-velocity vectors, dilatation scalar, and rotation vector. Then, we calculate the P-wave energy flux density vector by multiplying the P-wave particle-velocity vector by dilatation scalar, and we calculate the S-wave energy flux density vector as a cross product of the S-wave particle-velocity vector and rotation vector. The vectors can indicate accurate propagation directions of P- and S-waves, respectively, without being interfered by the superposition of the two wave modes.
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6

Zhang, Zhen-Dong y Tariq Alkhalifah. "Wave-equation Rayleigh-wave dispersion inversion using fundamental and higher modes". GEOPHYSICS 84, n.º 4 (1 de julio de 2019): EN57—EN65. http://dx.doi.org/10.1190/geo2018-0506.1.

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Recorded surface waves often provide reasonable estimates of the S-wave velocity in the near surface. However, existing algorithms are mainly based on the 1D layered-model assumption and require picking the dispersion curves either automatically or manually. We have developed a wave-equation-based inversion algorithm that inverts for S-wave velocities using fundamental and higher mode Rayleigh waves without picking an explicit dispersion curve. Our method aims to maximize the similarity of the phase velocity spectrum ([Formula: see text]) of the observed and predicted surface waves with all Rayleigh-wave modes (if they exist) included in the inversion. The [Formula: see text] spectrum is calculated using the linear Radon transform applied to a local similarity-based objective function; thus, we do not need to pick velocities in spectrum plots. As a result, the best match between the predicted and observed [Formula: see text] spectrum provides the optimal estimation of the S-wave velocity. We derive S-wave velocity updates using the adjoint-state method and solve the optimization problem using a limited-memory Broyden-Fletcher-Goldfarb-Shanno algorithm. Our method excels in cases in which the S-wave velocity has vertical reversals and lateral variations because we used all-modes dispersion, and it can suppress the local minimum problem often associated with full-waveform inversion applications. Synthetic and field examples are used to verify the effectiveness of our method.
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7

Socco, Laura Valentina, Cesare Comina y Farbod Khosro Anjom. "Time-average velocity estimation through surface-wave analysis: Part 1 — S-wave velocity". GEOPHYSICS 82, n.º 3 (1 de mayo de 2017): U49—U59. http://dx.doi.org/10.1190/geo2016-0367.1.

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In some areas, the estimation of static corrections for land seismic data is a critical step of the processing workflow. It often requires the execution of additional surveys and data analyses. Surface waves (SWs) in seismic records can be processed to extract local dispersion curves (DCs) that can be used to estimate near-surface S-wave velocity models. Here we focus on the direct estimation of time-average S-wave velocity models from SW DCs without the need to invert the data. Time-average velocity directly provides the value of one-way time, given a datum plan depth. The method requires the knowledge of one 1D S-wave velocity model along the seismic line, together with the relevant DC, to estimate a relationship between SW wavelength and investigation depth on the time-average velocity model. This wavelength/depth relationship is then used to estimate all the other time-average S-wave velocity models along the line directly from the DCs by means of a data transformation. This approach removes the need for extensive data inversion and provides a simple method suitable for industrial workflows. We tested the method on synthetic and field data and found that it is possible to retrieve the time-average velocity models with uncertainties less than 10% in sites with laterally varying velocities. The error on one-way times at various depths of the datum plan retrieved by the time-average velocity models is mostly less than 5 ms for synthetic and field data.
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8

Mora, Peter. "Elastic wave‐field inversion of reflection and transmission data". GEOPHYSICS 53, n.º 6 (junio de 1988): 750–59. http://dx.doi.org/10.1190/1.1442510.

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Elastic inversion of multioffset seismic data by wave‐ field fitting yields a maximum probability P-wave and S-wave velocity and density model of the Earth. Theoretically, the inversion accounts for all elastic waves including reflected and transmitted waves, mode conversions, shear waves, head waves, Rayleigh waves, etc. These different wave types tend to resolve different components of the Earth properties. By inverting two‐ component synthetic data, I show that reflection data mainly resolve high wavenumbers, while transmission data mainly resolve low wavenumbers of the P-wave and S-wave velocity model. The inversion of reflection data (shot gathers) yields a result that looks like a prestack elastic migration but the meaning of the inverted data is not simply reflectivity: it is the P-wave and S-wave velocity perturbation. The inversion of transmission data (VSPs) yields a solution that contains useful interval velocity information and is comparable to an elastic diffraction tomography result.
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9

Chmiel, M., A. Mordret, P. Boué, F. Brenguier, T. Lecocq, R. Courbis, D. Hollis, X. Campman, R. Romijn y W. Van der Veen. "Ambient noise multimode Rayleigh and Love wave tomography to determine the shear velocity structure above the Groningen gas field". Geophysical Journal International 218, n.º 3 (24 de mayo de 2019): 1781–95. http://dx.doi.org/10.1093/gji/ggz237.

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SUMMARY The Groningen gas field is one of the largest gas fields in Europe. The continuous gas extraction led to an induced seismic activity in the area. In order to monitor the seismic activity and study the gas field many permanent and temporary seismic arrays were deployed. In particular, the extraction of the shear wave velocity model is crucial in seismic hazard assessment. Local S-wave velocity-depth profiles allow us the estimation of a potential amplification due to soft sediments. Ambient seismic noise tomography is an interesting alternative to traditional methods that were used in modelling the S-wave velocity. The ambient noise field consists mostly of surface waves, which are sensitive to the Swave and if inverted, they reveal the corresponding S-wave structures. In this study, we present results of a depth inversion of surface waves obtained from the cross-correlation of 1 month of ambient noise data from four flexible networks located in the Groningen area. Each block consisted of about 400 3-C stations. We compute group velocity maps of Rayleigh and Love waves using a straight-ray surface wave tomography. We also extract clear higher modes of Love and Rayleigh waves. The S-wave velocity model is obtained with a joint inversion of Love and Rayleigh waves using the Neighbourhood Algorithm. In order to improve the depth inversion, we use the mean phase velocity curves and the higher modes of Rayleigh and Love waves. Moreover, we use the depth of the base of the North Sea formation as a hard constraint. This information provides an additional constraint for depth inversion, which reduces the S-wave velocity uncertainties. The final S-wave velocity models reflect the geological structures up to 1 km depth and in perspective can be used in seismic risk modelling.
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Su, Yuanda, Xinding Fang y Xiaoming Tang. "Measurement of the shear slowness of slow formations from monopole logging-while-drilling sonic logs". GEOPHYSICS 85, n.º 1 (6 de diciembre de 2019): D45—D52. http://dx.doi.org/10.1190/geo2019-0236.1.

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Acoustic logging-while-drilling (LWD) is used to measure formation velocity/slowness during drilling. In a fast formation, in which the S-wave velocity is higher than the borehole-fluid velocity, monopole logging can be used to obtain P- and S-wave velocities by measuring the corresponding refracted waves. In a slow formation, in which the S-wave velocity is less than the borehole-fluid velocity, because the fully refracted S-wave is missing, quadrupole logging has been developed and used for S-wave slowness measurement. A recent study based on numerical modeling implies that monopole LWD can generate a detectable transmitted S-wave in a slow formation. This nondispersive transmitted S-wave propagates at the formation S-wave velocity and thus can be used for measuring the S-wave slowness of a slow formation. We evaluate a field example to demonstrate the applicability of monopole LWD in determining the S-wave slowness of slow formations. We compare the S-wave slowness extracted from a monopole LWD data set acquired in a slow formation and the result derived from the quadrupole data recorded in the same logging run. The results indicated that the S-wave slowness can be reliably determined from monopole LWD sonic data in fairly slow formations. However, we found that the monopole approach is not applicable to very slow formations because the transmitted S-wave becomes too weak to detect when the formation S-wave slowness is much higher than the borehole-fluid slowness.
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Tesis sobre el tema "S-wave velocity"

1

KHOSRO, ANJOM FARBOD. "S-wave and P-wave velocity model estimation from surface waves". Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2912984.

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2

Ikeda, Tatsunori. "Improvement of surface wave methods for constructing subsurface S-wave velocity structures". 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188570.

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Larson, Angela Marie. "S-wave velocity structure beneath the Kaapvaal Craton from surface-wave inversions compared with estimates from mantle xenoliths". Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/34200.

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Results from two-station surface-wave inversions across the Archean Kaapvaal craton of southern Africa are compared with seismic velocities estimated from approximately 100 mantle xenoliths brought to the surface in kimberlite pipes. As the xenoliths represent a snapshot of the mantle at the time of their eruption, comparison with recently recorded seismic data provides an opportunity to compare and contrast the independently gained results. These cratonic xenoliths from the southern Kaapvaal, all less than 100Ma in age, have been analyzed geothermobarometrically to obtain the equilibrium P-T conditions of the cratonic mantle to about 180km depth [James et al 2004]. Seismic velocity-depth and density-depth profiles calculated on the basis of these P-T data and the mineral modes of the xenoliths are used to produce theoretical surface-wave dispersion curves and to generate roughly the upper 200km of a starting/reference model. A regionally-developed crustal structure [Niu and James 2002] was used for the crust and 300km of mantle values taken from PREM filled in down to 500km depth. This composite model was used as the starting/reference model for a Neighbourhood Algorithm surface-wave inversion using fundamental-mode Rayleigh-wave phase velocities for 16 paths within the Kaapvaal Craton from five events. The velocity structures found by that inversion are consistent with those derived from the xenolith data. Hence the velocity structure (i.e. thermal structure) of the mantle to a depth of 180km beneath the Kaapvaal craton is basically the same today as it was 80-90Ma. Further, synthetics runs show that for this surface-wave dataset, there is no strong low-velocity zone at depths shallower than at least 200km.
Master of Science
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4

Freudenreich, Yann Pierre. "P- and S-wave velocity estimation from full wavefield inversion of wide-aperture seismic data". Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620695.

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Chan, Ne Xun. "One- and Three-dimensional P- and S-wave Velocity Models of Central and Southern Sweden Based on SNSN Data". Thesis, Uppsala universitet, Geofysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-231929.

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The velocity structures of southern and central part of Sweden have been derived with the local tomography (LET) method. The region has been divided into two study areas and the datasets come from the P- and S-wave traveltimes recorded by the Swedish National Seismic Network (SNSN). Man-made explosions and earthquakes occurring over the period of 5 years and 10 years, respectively, within the study areas have been used. One-dimensional starting models were derived based on an a priori model obtained from the SNSN, that were later used for starting models in the inversion for the 3-D crustal structures of the study areas. Attempts were also made to invert for Moho topography in the areas. The study areas are found to have an upper-crustal thickness of approximately 20 to 25 km and the Moho boundaries vary from 42 to 46 km in depth. The Vp/Vs ratios varies from about 1.68 to 1.78. The LET method appear to resolve the different between the Sveconorgwegian and Svecofennian orogen regions, but the stations and sources are too sparsely distributed for higher resolution models. The seismicity in the study areas are distributed in two distinctive depth ranges. The focal depth of the SNSN catalogued earthquakes concentrated in approximately 5 km and 15 - 20 km depth. Relocations of the earthquakes using a global search method reduced this tendency. The results also show that using 3-D models produces less biased results than using 1-D models with the same relocation method.
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6

Sisman, Fatma Nurten. "Estimation Of Dynamic Soil Properties And Soil Amplification Ratios With Alternative Techniques". Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615501/index.pdf.

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Earthquakes are among the most destructive natural disasters affecting urban populations. Structural damage caused by the earthquakes varies depending not only on the seismic source and propagation properties but also on the soil properties. The amplitude and frequency content of seismic shear waves reaching the earth&rsquo
s surface is dependent on local soil conditions. It is well known that the soft sediments on top of hard bedrock can greatly amplify the ground motion and cause severe structural damage. When the fundamental period of the soil is close to the fundamental period of a structure, structural damage increases significantly. Estimation of the fundamental periods, amplification factors and types of soils is critical in terms of reduction of loss and casualties. For the reasons stated, estimation of dynamic behavior of soils has become one of the major topics of earthquake engineering. Studies for determining dynamic properties of soils depend fundamentally on the estimation of the S-wave velocity profiles, amplification factors and ground response. In this study first, the Multi-Mode Spatial Autocorrelation (MMSPAC) method is used to estimate the S-wave velocity profiles at the sites of interest. This method is different than the other ones in the sense that it works for the higher modes as well as the fundamental mode. In the second part, Horizontal to Vertical Spectral Ratio (HVSR) method will be used on both microtremor and ground motion data. Finally, the amplification factors from alternative methods are compared with each other. Consistent results are obtained in terms of both fundamental frequencies and amplification factors.
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7

Mainsant, Guenolé. "Variation de la vitesse des ondes de cisaillement lors de la transition solide-liquide au sein des argiles. Application aux glissements de terrain". Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENU005/document.

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Les glissements de terrain argileux affectent de nombreux versants à travers le monde et menacent régulièrement les activités humaines dans les zones urbanisées montagneuses. Ces glissements sont caractérisés par des cinématiques souvent lentes mais ils peuvent brutalement se liquéfier et accélérer de manière imprévisible. Cette transition solide-liquide a été étudiée sur les argiles de la région du Trièves (Alpes Françaises) à l'aide d'études rhéologiques. Elles ont montré le caractère de fluide à seuil thixotrope avec une bifurcation de viscosité importante lors de la fluidification pouvant expliquer le caractère catastrophique de l'accélération observée sur le terrain. Cette perte de rigidité du matériau peut être observée par une chute de la vitesse des ondes de cisaillement (Vs). Des études réalisées en parallèle à la fois sur un modèle analogique de plan incliné et sur le terrain (glissement de Pont-Bourquin, Suisse) ont permis d'observer une chute de Vs précédent à cette fluidification montrant ainsi que Vs pourrait être un bon proxy pour la surveillance des instabilités de terrain argileux
Landslides affect many clay slopes in the world and regularly threaten people in urban areas mountainous. These landslides are characterized by a slow velocity but they may suddenly liquefy and accelerate unexpectedly. The solid-liquid transition on the clay has been studied of Trièves region (French Alps) using rheological experiments. They have shown the yield stress thixotropic behavior with a viscosity bifurcation which can explain the catastrophic fluidization observed in the field. This loss of material stiffness can be followed by a drop in the shear wave velocity (Vs). Inclined plane test and field experiments (Pont-Bourquin landslides in Switzerland) have both shown a precursor drop of Vs indicating that it could be a good proxy for monitoring unstable clay slope
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8

Baden, Dawin Harry. "Caractérisation des propriétés élastiques d'un réservoir carbonaté hétérogène et fracturé". Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0581/document.

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Les réservoirs carbonatés sont exploités pour leur réserve d’eau potable, de ressource géothermique ou le stockage géologique du dioxyde de carbone. Ces réservoirs sont difficiles à caractériser à cause d’une histoire diagénétique souvent complexe. Cette thèse offre de nouvelles perspectives sur la caractérisation des propriétés pétrophysiques et élastiques des calcaires urgoniens de Provence. Une approche intégrée et multi-échelle est proposée pour caractériser les propriétés pétrophysiques et élastiques des carbonates. Cette étude est basée sur des mesures de vitesse d’ondes P (Vp) et S (Vs) à l’échelle du laboratoire (centimètre–décimètre) et du terrain (mètre–décamètre). En laboratoire, les Vp et Vs ainsi que l’anisotropie sont mesurées sur des plugs et sur des carottes, en utilisant différentes fréquences centrales ultrasonores. Sur le terrain, l’approche consiste à mesurer les Vp et Vs entre deux puits distant de 2 m sur une profondeur de 14 m. Les mesures sont ensuite interprétées en fonction de la géologie observée aux échelles macro- et microscopiques. Les principaux résultats montrent que les Vp et Vs moyennes sont indépendantes de l’échelle de mesure, car elles sont dictées par la porosité. L’anisotropie causée par les fractures (15%) et les hétérogénéités (5%) se manifestent par une variabilité autour des vitesses moyennes. L’approche adoptée ici a permis de définir les interactions entre les propriétés de la matrice, les hétérogénéités, les fractures et les propriétés élastiques des roches carbonatées. Elle a montré que les propriétés élastiques tout comme les structures géologiques varient en fonction de l’échelle
Carbonate reservoirs are also exploited for water production, geothermal energy, and carbon geological storage. Their Geophysical characterization remains challenging because of complex diagenetic history. This work offers new insights into the characterization of petrophysical, and elastic properties of the Urgonian limestones in the Provence region. An integrated multi-scale approach is proposed to characterize carbonate rocks petrophysical and elastic properties. This study relies on P- and S-wave velocity (Vp and Vs) measurements carried out at laboratory (centimeter–decimeter) and field (meter–decameter) scales. Laboratory scale Vp, Vs, and anisotropy are measured on plugs and cores, while on the field they are measured between two boreholes (crosshole) over a distance of 2 m and 14 m depth. The measurements are then compared to the geology from the macro- to the microscopic scale. The main results show that the average Vp and Vs are porosity related, and are independent from scale. Anisotropy caused by fractures (15%) and heterogeneities (5%) is responsible for variations around the mean velocities. The approach adopted during this work has enabled to scope out the interplay between matrix properties, heterogeneity, fracturing, and elastic properties in carbonate rocks. It has shown that the elastic properties evolve with scale as well as the geological structures
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9

Tichoň, Dušan. "Analýza šíření tlakové vlny v aortě". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-418205.

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The aim of this diploma thesis is to assess the applicability of pulse wave propagation monitoring in the cardiovascular system in the field of prediction and early diagnosis of abdominal aortic aneurysm (AAA). The very first part is focused on description of heart and blood vessels with its pathological changes in presence of aneurysm. For this reason, current methods of monitoring and surgical treating of AAA were mentioned. Due to their difficult clinical use widely in the population, new methods based on pulse wave monitoring were presented. Using an analytical approach we estimated the difference in the arrival of the pulse wave at measurable locations between healthy and pathological aorta in the order of miliseconds. By experimental monitoring using photoplethysmographic sensors, we observed significant changes of pulse wave velocity with respect to the mechanical properties of the artery wall (mainly associated with age), which we tried to implement by hyperelastic material models used in computational simulations of pulse wave proagation on simplified geometries by fluid structure interaction method. These analyzes should verify applicability of FSI simulations in further development of diagnostic methods of AAA.
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10

Bianchi, Marcelo Belentani de. "Variações da estrutura da crosta, litosfera e manto para a plataforma Sul Americana através de funções do receptor para ondas P e S". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/14/14132/tde-22092008-121708/.

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Utilizamos neste trabalho duas metodologias distintas, a função do receptor com ondas P e a função do receptor com ondas S, para mapear variações da crosta e interfaces do manto (litosfera-astenosfera, 410 km e 660 km) em diferentes estações sismográficas na placa Sul-Americana. No estudo da interface litosfera-astenosfera, por ser o primeiro realizado nesta região, utilizamos as estações temporárias do IAG/USP em conjunto com as estações permanentes da rede mundial cobrindo toda a placa Sul-Americana. O estudo para as outras interfaces (Crosta-Manto, 410 km e 660 km) foi feito com caráter regional, buscando detalhar características da crosta e manto na região estável da placa. Para ambos os métodos os traços (sismogramas) foram rotacionados para o sistema LQT, deconvolvidos, agrupados por pontos de perfuração e por estações, e finalmente empilhados. Nos traços empilhados as fases convertidas de interesse (Ps, Ppps, Ppss+Psps e Sp) foram identificadas e interpretadas. Para a parte estável da placa obtivemos um valor médio de espessura da crosta de 39.4±0.6 km, variando desde 31.0±0.5 km para a província Borborema, até 41.3±1.0 km para a bacia do Paraná, onde aplicamos uma correção para descontar o efeito do sedimento. A razão de velocidade para a crosta, Vp/Vs, apresentou valores mais altos para a bacia do Paraná (~1.75±0.08) e região litorânea oriental (>1.74), enquanto que as regiões cratônicas (cráton São Francisco e Amazônico) apresentaram valores de Vp/Vs baixos (<1.72), chegando até 1.68. O valor médio de Vp/Vs para todas as estações analisadas foi de 1.73±0.02. As variações dos tempos para as interfaces do manto mostraram boa correlação com resultados de tomografia sísmica de outros trabalhos, indicando alterações de até 5% na velocidade das ondas sísmicas para o manto superior sob os crátons, uma deflexão de até 15 km na interface de 660 km para a região Sul da bacia do Paraná e se mostraram bem correlacionadas com as médias globais para as outras região estudadas. Por fim, a espessura da litosfera apresentou valores desde ~40 km, sob as regiões de ilhas oceânicas, até ~160 km, sob as regiões mais estáveis. Para as regiões oceânicas a espessura da litosfera se mostra correlacionada com a idade da placa. À medida que adentramos a parte continental, o limite litosfera-astenosfera se torna menos proeminente, atingindo profundidades maiores no interior dos continentes e menores para as regiões marginais. Para a zona de subducção, observamos duas possíveis litosferas, uma oceânica, subduzindo junto com a placa de Nazca, e outra pertencente à parte continental.
Two distinct methodologies, the P- and S-wave receiver functions, are used to map variations in the crustal parameters (thickness and Vp/Vs) and mantle interfaces (lithosphere-asthenosphere, 410 km and 660 km) on a number of different seismograph stations located in the South American plate. The results of the S receiver function for the lithosphere-asthenosphere boundary are the first of this kind ever performed in South American continent and showed the large scale variations of this interface. To perform this study we analyze data from various global permanent stations together with all available data from temporary stations operated by the IAG/USP during the last15 years. For both methods the traces (seismograms) were rotated to the LQT system, deconvolved, grouped by piercing points and stations, and finally stacked. In the stacked traces, the converted phases (Ps, Ppps, Ppss+Psps and Sp) were identified and interpreted. Inside the stable part of the plate we found a mean crustal thickness of 39.4±0.6 km, ranging from 31.0±0.5 km in Borborema Province up to 41.3±1.0 km in the Paraná Basin, where we applied a correction to remove the sediment effects on the crustal estimates. The crustal velocity ratios, Vp/Vs, showed higher values for the Paraná Basin (~1.75±0.08) and Ribeira belt (>1.74), while the cratonic regions (São Francisco and Amazon cratons) showed low values of Vp/Vs (<1.72), down to 1.68. The average Vp/Vs obtained for all stations was equal to 1.73±0.02. The observed times of the converted mantle phases presented a good correlation with other tomographic studies, indicating that the upper mantle for the cratonic roots may be characterized by a variation up to 5% in seismic velocities, a 15 km deflection in the South Paraná 660 km discontinuity (probably due to a decreased temperature caused by the subducted slab); for other regions the converted times were close to the global average. As a final result, the lithospheric thickness presented values ranging from ~40 km under oceanic islands, to ~160 km under the stable continental regions. We found that for the oceanic islands the thickness of the lithosphere is correlated with the age of the plate. When we go further inside the continents, the lithosphere-asthenosphere boundary becomes less sharp, reaching larger depths inside the continents and shallower depths near the continental margin. In the Andean subduction area, we observed two possibles lithospheres, one oceanic, subducting together with the Nazca plate, and another belonging to the Continent, parallel to the crust interface.
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Libros sobre el tema "S-wave velocity"

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Zielhuis, Aletta. S-wave velocity below Europe from delay-time and waveform inversions. [Utrecht: Instituut voor Aardwetenschappen de Rijksuniversiteit te Utrecht, 1992.

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B, Dawson Phillip y Geological Survey (U.S.), eds. Data report for a seismic study of the P and S wave velocity structure of Redoubt Volcano, Alaska. [Menlo Park, Calif.]: U.S. Dept. of the Interior, U.S. Geological Survey, 1996.

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Capítulos de libros sobre el tema "S-wave velocity"

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Soto, Jorge y Jorge E. Alva. "Estimation of Deep S-Wave Velocity Profile Using Seismic Records Case of Lima, Peru". En Current Trends in Geotechnical Engineering and Construction, 421–32. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-7358-1_36.

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Qureshi, Mohsin Usman, Suguru Yamada y Ikuo Towhata. "A Simplified Technique for Slope Stability Assessment Based on Insitu S-Wave Velocity Measurement". En Earthquake-Induced Landslides, 871–81. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-32238-9_95.

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Lee, Jeong Ki, Young H. Kim y Ho Chul Kim. "Group Velocity of Lamb Wave S0 Mode in Laminated Unidirectional CFRP Plates". En Key Engineering Materials, 2213–18. Stafa: Trans Tech Publications Ltd., 2005. http://dx.doi.org/10.4028/0-87849-978-4.2213.

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Liu, Yongbo, Zhuoshi Chen, Xiaoming Yuan y Longwei Chen. "The Uncertainty of In-situ S and P Wave Velocity Test at Xichang Experimental Field of CSES". En Proceedings of the 4th International Conference on Performance Based Design in Earthquake Geotechnical Engineering (Beijing 2022), 944–51. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-11898-2_71.

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Gaci, Said. "A NOVEL MODEL TO ESTIMATE S-WAVE VELOCITY INTEGRATING HÖLDERIAN REGULARITY, EMPIRICAL MODE DECOMPOSITION, AND MULTILAYER PERCEPTRON NEURAL NETWORKS". En Oil and Gas Exploration, 181–200. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781119227519.ch12.

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Hayashi, Koichi, Tomio Inazaki, Kaoru Kitao y Takaho Kita. "Statistical Estimation of Soil Parameters in from Cross-Plots of S-Wave Velocity and Resistivity Obtained by Integrated Geophysical Method". En Levees and Dams, 1–21. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-27367-5_1.

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Yu, Kaiwen, Changhai Han, Kang Han, Jianjun Zhao y Zhiguang Yu. "Experimental Study on Navigation Flow Condition of Downstream Approach Channel of Navigation Facilities of Baise Water Conservancy Project". En Lecture Notes in Civil Engineering, 1471–80. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-6138-0_130.

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AbstractBaise Water Conservancy Project is the second cascade in the Yujiang River planning, and its navigation facilities are one of the key projects to get through Yunnan and Guizhou. The exit of the downstream approach channel of the navigation facilities of the Baise Water Conservancy Project is located about 700 m downstream of the Dongsun Hydropower Station, so the operation of Dongsun Hydropower Station has a direct impact on the navigation flow condition of the approach channel. In addition, the topography of the river also has an obvious influence on the navigation conditions at the entrance area of the approach channel. So, based on the overall hydraulic model with a scale of 1:80 and the self-navigating ship simulation test, the navigation flow conditions at the entrance area of the approach channel and the characteristics of the ship entering and exiting the ship lock were studied. The test results show that: (1) Under the condition that the discharge of Dongsun Hydropower Station is less than1500 m3/s at full power, the flow pattern in the downstream channel of the hydropower station and the entrance area of the approach channel is relatively smooth. The flow pattern, velocity and wave height can meet the specification requirements. The maximum rudder angle and drift angle at the entrance area of the approach channel do not exceed the requirements, and the ship can enter and exit the downstream approach channel smoothly; (2) The maximum navigation discharge of 1700 m3/s can be achieved by adjusting the route of the connecting section of the downstream approach channel to the left bank and dredging the two convex points on the right bank of the entrance area of the downstream approach channel.
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Hemeda, Sayed. "Determining the S-Wave Velocity by Using Refraction Microtremors Technique". En An Integrated Geophysical and Geotechnical Assessment of Hazards Around the Abu Serga Church, 4–20. BENTHAM SCIENCE PUBLISHERS, 2021. http://dx.doi.org/10.2174/9789814998727121010003.

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Newnham, Robert E. "Acoustic waves I". En Properties of Materials. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780198520757.003.0025.

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In this chapter we treat plane waves specified by a wave normal and a particle motion vector . Two types of waves, longitudinal waves and shear waves, are observed in solids. For low symmetry directions, there are generally three different waves with the same wave normal, a longitudinal wave and two shear waves. The particle motions in the three waves are perpendicular to one another. Only longitudinal waves are present in liquids because of their inability to support shear stresses. The transverse waves are strongly absorbed. Acoustic wave velocities (v) are controlled by elastic constants (c) and density (ρ). For a stiff ceramic (c ∼ 5 × 1011 N/m2) and density (ρ ∼ 5 g/cm3 = 5000 kg/m3), the wave velocity is about 104 m/s. For low frequency vibrations near 1 kHz the wavelength λ is about 10 m. The shortest wavelengths are around 1 nm and correspond to infrared vibrations of 1013 Hz. Acoustic wave velocities for polycrystalline alkali metals are plotted in Fig. 23.2. Longitudinal waves travel at about twice the speed of transverse shear waves since c11 > c44. Sound is transmitted faster in light metals like Li which have shorter, stronger bonds and lower density than heavy alkali atoms like Cs. The tensor relation between velocity and elastic constants is derived using Newton’s Laws and the differential volume element shown in Fig. 23.3(a). The volume is equal to (δZ1) (δZ2) (δZ3). Acoustic waves are characterized by regions of compression and rarefaction because of the periodic particle displacements associated with the wave. These displacements are caused by the inhomogeneous stresses emanating from the source of the sound. In tensor form the components of the stress gradient are ∂Xij/∂Zk and will include both tensile stress gradients and shear stress gradients, as pictured in Fig. 23.3(b). The force F acting on the volume element is calculated by multiplying the stress components by the area of the faces on which the force acts.
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Costanzo, Maria Rosaria y Concettina Nunziata. "S-wave velocity profiling for site response evaluation in urban areas". En Earthquakes and Sustainable Infrastructure, 195–213. Elsevier, 2022. http://dx.doi.org/10.1016/b978-0-12-823503-4.00028-2.

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Actas de conferencias sobre el tema "S-wave velocity"

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Zhang*, Minyu y Robert R. Stewart. "S-wave velocity estimation using converted-wave VSP data". En SEG Technical Program Expanded Abstracts 2014. Society of Exploration Geophysicists, 2014. http://dx.doi.org/10.1190/segam2014-0618.1.

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Huang, Zhongyu, Xu Yiming, Yu Bo y Wang Yujing. "PS‐wave statics with near‐surface S‐wave velocity models". En SEG Technical Program Expanded Abstracts 2010. Society of Exploration Geophysicists, 2010. http://dx.doi.org/10.1190/1.3513165.

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Socco, Valentina y Daniele Boiero. "S-wave Velocity from P-wave Reflection Data: The Role of Surface Waves". En 74th EAGE Conference and Exhibition - Workshops. Netherlands: EAGE Publications BV, 2012. http://dx.doi.org/10.3997/2214-4609.20149867.

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Geng, Weifeng, Aiyuan Hou, Wenbo Zhang y Na Lei. "Acquiring S‐wave velocity using VSP converted wave of P‐wave source". En SEG Technical Program Expanded Abstracts 2009. Society of Exploration Geophysicists, 2009. http://dx.doi.org/10.1190/1.3255740.

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Jaramillo, Heman H. y Paul J. Fowler. "P‐S converted‐wave DMO indepth‐variable velocity". En SEG Technical Program Expanded Abstracts 1997. Society of Exploration Geophysicists, 1997. http://dx.doi.org/10.1190/1.1885725.

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Zhi‐hua, Wu y Yin Xing‐yao. "Estimation of S‐wave velocity in carbonate reservoir". En Technical Program Expanded Abstracts, editado por Huimin Hao y Jie Zhang. Society of Exploration Geophysicists, 2011. http://dx.doi.org/10.1190/1.4705015.

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Vaezi, Y. y K. DeMeersman. "Supervirtual S-wave Refraction Interferometry for Converted Wave Statics and Near-surface S-wave Velocity Model Building". En 76th EAGE Conference and Exhibition 2014. Netherlands: EAGE Publications BV, 2014. http://dx.doi.org/10.3997/2214-4609.20140996.

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Valentina Socco, Laura y Politecnico di Torino. "P- and S-wave velocity model estimation from surface wave data". En 7th International Conference on Environment and Engineering Geophysics & Summit Forum of Chinese Academy of Engineering on Engineering Science and Technology. Paris, France: Atlantis Press, 2016. http://dx.doi.org/10.2991/iceeg-16.2016.33.

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Edme, Pascal y Ed Kragh. "Near‐surface S‐wave velocity estimation from P‐wave polarization analysis". En SEG Technical Program Expanded Abstracts 2009. Society of Exploration Geophysicists, 2009. http://dx.doi.org/10.1190/1.3255780.

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Edme, P. y E. Kragh. "Near-surface S-wave Velocity Estimation from P-wave Polarization Analysis". En 72nd EAGE Conference and Exhibition incorporating SPE EUROPEC 2010. European Association of Geoscientists & Engineers, 2010. http://dx.doi.org/10.3997/2214-4609.201401113.

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Informes sobre el tema "S-wave velocity"

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Pulliam, Robert Jay. Imaging earth`s interior: Tomographic inversions for mantle P-wave velocity structure. Office of Scientific and Technical Information (OSTI), julio de 1991. http://dx.doi.org/10.2172/10132746.

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Park, Y., A. Nyblade, A. Rodgers y A. Al-Amri. Tomographic Imaging of Upper Mantle P- and S-wave Velocity Heterogeneity Beneath the Arabian Peninsula. Office of Scientific and Technical Information (OSTI), agosto de 2005. http://dx.doi.org/10.2172/878613.

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Stokoe, Kenneth H., Song Cheng Li, Brady R. Cox y Farn-Yuh Menq. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume IV S-Wave Measurements in Borehole C4993 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile. Office of Scientific and Technical Information (OSTI), junio de 2007. http://dx.doi.org/10.2172/912741.

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Stokoe, Kenneth H., Song Cheng Li, Brady R. Cox y Farn-Yuh Menq. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume V S-Wave Measurements in Borehole C4996 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile. Office of Scientific and Technical Information (OSTI), junio de 2007. http://dx.doi.org/10.2172/912742.

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Stokoe, Kenneth H., Song Cheng Li, Brady R. Cox y Farn-Yuh Menq. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume VI S-Wave Measurements in Borehole C4997 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile. Office of Scientific and Technical Information (OSTI), junio de 2007. http://dx.doi.org/10.2172/912743.

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Toksoez, M. N. y Youshun Sun. P and S Wave Velocity Structure of the Crust and Upper Mantle Under China and Surrounding Areas From Body and Surface Wave Tomography. Fort Belvoir, VA: Defense Technical Information Center, marzo de 2008. http://dx.doi.org/10.21236/ada486734.

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Diehl, John y Robert Steller. Final Data Report: P- and S-Wave Velocity Logging Borings C4993, C4996, and C4997 Part B: Overall Logs. Office of Scientific and Technical Information (OSTI), marzo de 2007. http://dx.doi.org/10.2172/912727.

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Steller, Robert y John Diehl. Final Data Report: P- and S-Wave Velocity Logging Borings C4993, C4996, and C4997 Part A: Interval Logs. Office of Scientific and Technical Information (OSTI), febrero de 2007. http://dx.doi.org/10.2172/912737.

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Broome, Scott y Johnny Jaramillo. P- and S-Wave velocity and Indirect Tensile Measurements for Alluvium in Support of the Source Physics Experiments. Office of Scientific and Technical Information (OSTI), mayo de 2021. http://dx.doi.org/10.2172/1821791.

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Wideman, Jr., Robert F., Nicholas B. Anthony, Avigdor Cahaner, Alan Shlosberg, Michel Bellaiche y William B. Roush. Integrated Approach to Evaluating Inherited Predictors of Resistance to Pulmonary Hypertension Syndrome (Ascites) in Fast Growing Broiler Chickens. United States Department of Agriculture, diciembre de 2000. http://dx.doi.org/10.32747/2000.7575287.bard.

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Background PHS (pulmonary hypertension syndrome, ascites syndrome) is a serious cause of loss in the broiler industry, and is a prime example of an undesirable side effect of successful genetic development that may be deleteriously manifested by factors in the environment of growing broilers. Basically, continuous and pinpointed selection for rapid growth in broilers has led to higher oxygen demand and consequently to more frequent manifestation of an inherent potential cardiopulmonary incapability to sufficiently oxygenate the arterial blood. The multifaceted causes and modifiers of PHS make research into finding solutions to the syndrome a complex and multi threaded challenge. This research used several directions to better understand the development of PHS and to probe possible means of achieving a goal of monitoring and increasing resistance to the syndrome. Research Objectives (1) To evaluate the growth dynamics of individuals within breeding stocks and their correlation with individual susceptibility or resistance to PHS; (2) To compile data on diagnostic indices found in this work to be predictive for PHS, during exposure to experimental protocols known to trigger PHS; (3) To conduct detailed physiological evaluations of cardiopulmonary function in broilers; (4) To compile data on growth dynamics and other diagnostic indices in existing lines selected for susceptibility or resistance to PHS; (5) To integrate growth dynamics and other diagnostic data within appropriate statistical procedures to provide geneticists with predictive indices that characterize resistance or susceptibility to PHS. Revisions In the first year, the US team acquired the costly Peckode weigh platform / individual bird I.D. system that was to provide the continuous (several times each day), automated weighing of birds, for a comprehensive monitoring of growth dynamics. However, data generated were found to be inaccurate and irreproducible, so making its use implausible. Henceforth, weighing was manual, this highly labor intensive work precluding some of the original objectives of using such a strategy of growth dynamics in selection procedures involving thousands of birds. Major conclusions, solutions, achievements 1. Healthy broilers were found to have greater oscillations in growth velocity and acceleration than PHS susceptible birds. This proved the scientific validity of our original hypothesis that such differences occur. 2. Growth rate in the first week is higher in PHS-susceptible than in PHS-resistant chicks. Artificial neural network accurately distinguished differences between the two groups based on growth patterns in this period. 3. In the US, the unilateral pulmonary occlusion technique was used in collaboration with a major broiler breeding company to create a commercial broiler line that is highly resistant to PHS induced by fast growth and low ambient temperatures. 4. In Israel, lines were obtained by genetic selection on PHS mortality after cold exposure in a dam-line population comprising of 85 sire families. The wide range of PHS incidence per family (0-50%), high heritability (about 0.6), and the results in cold challenged progeny, suggested a highly effective and relatively easy means for selection for PHS resistance 5. The best minimally-invasive diagnostic indices for prediction of PHS resistance were found to be oximetry, hematocrit values, heart rate and electrocardiographic (ECG) lead II waves. Some differences in results were found between the US and Israeli teams, probably reflecting genetic differences in the broiler strains used in the two countries. For instance the US team found the S wave amplitude to predict PHS susceptibility well, whereas the Israeli team found the P wave amplitude to be a better valid predictor. 6. Comprehensive physiological studies further increased knowledge on the development of PHS cardiopulmonary characteristics of pre-ascitic birds, pulmonary arterial wedge pressures, hypotension/kidney response, pulmonary hemodynamic responses to vasoactive mediators were all examined in depth. Implications, scientific and agricultural Substantial progress has been made in understanding the genetic and environmental factors involved in PHS, and their interaction. The two teams each successfully developed different selection programs, by surgical means and by divergent selection under cold challenge. Monitoring of the progress and success of the programs was done be using the in-depth estimations that this research engendered on the reliability and value of non-invasive predictive parameters. These findings helped corroborate the validity of practical means to improve PHT resistance by research-based programs of selection.
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