Academic literature on the topic 'Surface-wave dispersion analysis'
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Journal articles on the topic "Surface-wave dispersion analysis"
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Chávez-García, Francisco J., Jaime Ramos-Martínez, and Evangelina Romero-Jiménez. "Surface-wave dispersion analysis in Mexico City." Bulletin of the Seismological Society of America 85, no. 4 (August 1, 1995): 1116–26. http://dx.doi.org/10.1785/bssa0850041116.
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Abstract In this article, we present an observational investigation of ground motion at Mexico City focused on surface waves. Our purpose is 2-fold; first, to understand incident ground motion during the great Michoacán earthquake of 19 September 1985, and second, to characterize surface waves propagating in the lake-bed zone. To this end we analyze the strong-motion records obtained at Mexico City for the large (MS = 8.1) earthquake of 19 September 1985. It is shown that, in the low-frequency range, we observe the Rayleigh fundamental mode in both the vertical and the radial components, and the Love fundamental mode in the transverse component at all the strong-motion stations. The vertical component also shows the first higher mode of Rayleigh waves. We use a very broadband record obtained at station CU for the smaller (MS = 6.7) earthquake of 14 May 1993 to verify that the dispersion computed from the model of Campillo et al. (1989) represents well the average surface-wave propagation between the coast and Mexico City in the 7- to 10-sec period range. We use this result to assign absolute times to the strong-motion records of the Michoacán event. This allowed us to identify additional wave trains that propagate laterally in directions other than great circle in the 3- to 5-sec period range. These wave trains are identified as Love waves. In a second analysis, we study a set of refraction data obtained during a small-scale (250 m) experiment on the virgin clay of the lake-bed zone. Phase-velocity dispersion curves for several modes of Rayleigh waves are identified in the refraction data and inverted to obtain an S-wave velocity profile. This profile is used as the uppermost layering in a 2D model of Mexico City valley. The results of numerical simulation show that surface waves generated by lateral finiteness of the clay layer suffer large dispersion and attenuation. We conclude that surface waves generated by the lateral heterogeneity of the upper-most stratigraphy very significantly affect ground motion near the edge of the valley, but their importance is negligible for distances larger than 1.5 km from the edge. Thus, locally generated surface waves propagating through the clay layer cannot explain late arrivals observed for the 1985 event. We suggest that the long duration of strong motion is due to the interaction between lateral propagation of waves guided by deep layers (1 to 4 km) and the surficial clay layer. This interaction is possible by the coincidence of the dominant frequency of the uppermost layers and the frequency of the deeply guided waves.
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Lin, Chih-Ping, and Tzong-Sheng Chang. "Multi-station analysis of surface wave dispersion." Soil Dynamics and Earthquake Engineering 24, no. 11 (December 2004): 877–86. http://dx.doi.org/10.1016/j.soildyn.2003.11.011.
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Ikeda, Tatsunori, and Takeshi Tsuji. "Two-station continuous wavelet transform cross-coherence analysis for surface-wave tomography using active-source seismic data." GEOPHYSICS 85, no. 1 (January 1, 2020): EN17—EN28. http://dx.doi.org/10.1190/geo2019-0054.1.
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ABSTRACT Surface-wave tomography has great potential to improve the lateral resolution of near-surface characterization compared to 2D surface-wave analysis with multichannel analysis of surface waves (MASW). Surface-wave tomography has been widely applied to obtain high-resolution maps of phase or group velocity from dispersion curves between pairs of stations in seismological studies. However, very few studies have done surface-wave tomography with active-source (exploration) seismic data, probably because extracting surface-wave dispersion curves between two stations is difficult due to the complex wave propagation in heterogeneous near-surface structures. Here, we describe a method to estimate reliable phase-velocity dispersion curves between two stations from exploration seismic data. In our approach, we compute cross coherences between pairs of stations to extract phase information, stacking the cross coherences from different shot gathers to improve the signal-to-noise ratio. To further distinguish surface-wave signals from noise in the time domain, we perform a time-frequency analysis using the continuous wavelet transform (CWT) on the stacked cross coherences. We used modeling of the wavelet transform between station pairs to extract phase-velocity dispersion curves from the stacked cross coherences. We apply this two-station CWT cross-coherence method to synthetic and field data sets. Both applications demonstrate that our method can extract stable phase-velocity dispersion curves between two stations better than two-station or multistation analysis without time-domain filtering. In phase-velocity distributions constructed by surface-wave tomography from the dispersion curves between two stations, the horizontal resolution is improved over MASW-based analyses. Improvement of the horizontal resolution is also achieved in S-wave velocity structures derived by inversion of the phase-velocity distributions. Our method is effective in estimating reliable phase-velocity dispersion curves and may contribute to constructing high-resolution S-wave velocity models located with a laterally heterogeneous structure, by subsequent surface-wave tomography and S-wave velocity inversion.
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Addo, K. O., and P. K. Robertson. "Shear-wave velocity measurement of soils using Rayleigh waves." Canadian Geotechnical Journal 29, no. 4 (August 1, 1992): 558–68. http://dx.doi.org/10.1139/t92-063.
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A modified version of the spectral analysis of surface waves (SASW) equipment and analysis procedure has been developed to determine in situ shear-wave velocity variation with depth from the ground surface. A microcomputer has been programmed to acquire waveform data and perform the relevant spectral analyses that were previously done by signal analyzers. Experimental dispersion for Rayleigh waves is now obtainable at a site and inverted with a fast algorithm for dispersion computation. Matching experimental and theoretical dispersion curves has been automated in an optimization routine that does not require intermittent operator intervention or experience in dispersion computation. Shear-wave velocity profiles measured by this procedure are compared with results from independent seismic cone penetration tests for selected sites in western Canada. Key words : surface wave, dispersion, inversion, optimization, shear-wave velocity.
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Lin, Chih-Ping, Chun-Hung Lin, and Chih-Jung Chien. "Dispersion analysis of surface wave testing – SASW vs. MASW." Journal of Applied Geophysics 143 (August 2017): 223–30. http://dx.doi.org/10.1016/j.jappgeo.2017.05.008.
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Boiero, Daniele, Paolo Bergamo, Roberto Bruno Rege, and Laura Valentina Socco. "Estimating surface-wave dispersion curves from 3D seismic acquisition schemes: Part 1 — 1D models." GEOPHYSICS 76, no. 6 (November 2011): G85—G93. http://dx.doi.org/10.1190/geo2011-0124.1.
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Surface-wave analysis is based on the estimation of surface-wave dispersion curves, which are then inverted to provide 1D S-wave velocity profiles. Surface-wave dispersion curves can be extracted from P-wave records obtained in seismic exploration and used to characterize the ground structure at a shallow depth. Dispersion curve estimation using 2D wavefield transforms is well-established for 2D acquisition schemes (in-line source and receiver spread). It is possible to extract surface-wave dispersion curves using 2D wavefield transforms from 3D seismic data acquired with any acquisition scheme. In particular, we focus on areal geometry and orthogonal geometry, and we provide a method based on the analysis in the offset domain and the [Formula: see text] multiple signal classification (MUSIC) transform. We assess the performance of the method on synthetic and field data concerning 1D sites.
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Park, Choon B., Richard D. Miller, and Jianghai Xia. "Multichannel analysis of surface waves." GEOPHYSICS 64, no. 3 (May 1999): 800–808. http://dx.doi.org/10.1190/1.1444590.
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The frequency‐dependent properties of Rayleigh‐type surface waves can be utilized for imaging and characterizing the shallow subsurface. Most surface‐wave analysis relies on the accurate calculation of phase velocities for the horizontally traveling fundamental‐mode Rayleigh wave acquired by stepping out a pair of receivers at intervals based on calculated ground roll wavelengths. Interference by coherent source‐generated noise inhibits the reliability of shear‐wave velocities determined through inversion of the whole wave field. Among these nonplanar, nonfundamental‐mode Rayleigh waves (noise) are body waves, scattered and nonsource‐generated surface waves, and higher‐mode surface waves. The degree to which each of these types of noise contaminates the dispersion curve and, ultimately, the inverted shear‐wave velocity profile is dependent on frequency as well as distance from the source. Multichannel recording permits effective identification and isolation of noise according to distinctive trace‐to‐trace coherency in arrival time and amplitude. An added advantage is the speed and redundancy of the measurement process. Decomposition of a multichannel record into a time variable‐frequency format, similar to an uncorrelated Vibroseis record, permits analysis and display of each frequency component in a unique and continuous format. Coherent noise contamination can then be examined and its effects appraised in both frequency and offset space. Separation of frequency components permits real‐time maximization of the S/N ratio during acquisition and subsequent processing steps. Linear separation of each ground roll frequency component allows calculation of phase velocities by simply measuring the linear slope of each frequency component. Breaks in coherent surface‐wave arrivals, observable on the decomposed record, can be compensated for during acquisition and processing. Multichannel recording permits single‐measurement surveying of a broad depth range, high levels of redundancy with a single field configuration, and the ability to adjust the offset, effectively reducing random or nonlinear noise introduced during recording. A multichannel shot gather decomposed into a swept‐frequency record allows the fast generation of an accurate dispersion curve. The accuracy of dispersion curves determined using this method is proven through field comparisons of the inverted shear‐wave velocity ([Formula: see text]) profile with a downhole [Formula: see text] profile.
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Xi, Chaoqiang, Jianghai Xia, Binbin Mi, Tianyu Dai, Ya Liu, and Ling Ning. "Modified frequency–Bessel transform method for dispersion imaging of Rayleigh waves from ambient seismic noise." Geophysical Journal International 225, no. 2 (January 11, 2021): 1271–80. http://dx.doi.org/10.1093/gji/ggab008.
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SUMMARY Ambient noise surface wave methods have gained much attention among geophysical and civil engineering communities because of their capability of determining near-surface shear wave velocities in highly populated urban areas. Higher mode information of surface waves is important in dispersion curve inversion for shear wave velocity structure. The frequency–Bessel (F-J) transform method is an effective tool for multimode surface wave extraction, which has been applied to multiscale investigations of the Earth structure. The measured dispersion energy with the F-J method, however, would usually be contaminated by a type of ‘crossed’ artefacts at high frequencies, which are caused by spatial aliasing and bidirectional velocity scan of dispersion analysis methods. The ‘crossed’ artefacts usually cross and smear the true dispersion energy in the frequency–velocity domain. We propose a modified F-J (MFJ) transform method in which the Bessel function is replaced by the Hankel function for dispersion analysis of empirical Green's function. The MFJ method performs a unidirectional velocity scanning on the outgoing wave to avoid the ‘crossed’ artefacts. Synthetic and real-world examples demonstrate the effectiveness of the proposed MFJ method in improving the accuracy of Rayleigh wave multimode dispersion measurements.
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Wu, T. T., and Y. Y. Chen. "Wavelet Analysis of Laser-Generated Surface Waves in a Layered Structure With Unbond Regions." Journal of Applied Mechanics 66, no. 2 (June 1, 1999): 507–13. http://dx.doi.org/10.1115/1.2791076.
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This paper presents the results on the utilization of a wavelet transform to study the dispersion of laser-generated surface waves in an epoxy-bonded copper-aluminum layered specimen with and without unbond areas. Laser ultrasonic experiments based on the point-source/point-receiver (PS/PR) technique were undertaken to measure surface wave signals in a layered specimen. The wavelet transform with a Morlet wavelet function was adopted to analyze the group velocity dispersion of the surface wave signals. A novel hybrid formula for group velocity dispersion is proposed for measurements across unbond regions. Results and data obtained are in good agreement with calculated and experimental dispersion curves. The general behavior of the group velocity dispersion for different measurement, configurations can be utilized to differentiate the unbond regions in a layered structure.
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Hu, Shufan, Yonghui Zhao, Laura Valentina Socco, and Shuangcheng Ge. "Retrieving 2-D laterally varying structures from multistation surface wave dispersion curves using multiscale window analysis." Geophysical Journal International 227, no. 2 (July 20, 2021): 1418–38. http://dx.doi.org/10.1093/gji/ggab282.
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SUMMARY The analysis of multistation surface wave records is of increasing popularity in imaging the structure of the Earth due to its robustness on dispersion measurement. Since the representation of multistation surface wave dispersion curves (DCs) is uncertain in laterally varying media, average information beneath the receiver array is assumed to be obtained by inverting the dispersion curves with a horizontally layered model. To retrieve a more realistic 2-D laterally varying structure, we present a multiscale window analysis of surface waves (MWASW) method for analysing 2-D active-source surface wave data. The MWASW method is based on the use of a forward algorithm for calculating the theoretical DCs over 2-D models and multisize spatial windows for estimating the dispersion data. The forward algorithm calculates the theoretical dispersion considering the lateral variation beneath the receiver array; hence, the estimated DC is not treated as representative of the average properties but as data containing the lateral variation information. By inverting the dispersion data extracted from different spatial windows, the subsurface information at different depth ranges and lateral extensions are integrated to produce a shear wave velocity model. The dispersion curves analysed from smaller spatial windows retrieve the shallow structure with a higher lateral resolution, whereas the phase velocity data from larger spatial windows provide average information with a greater depth. We test the effectiveness of the MWASW method using three synthetic examples and two field data sets. Both results show the improved lateral resolution of the S-wave velocity structure retrieved with the MWASW method compared to the traditional multistation method in which the local horizontally layered model is adopted.
Dissertations / Theses on the topic "Surface-wave dispersion analysis"
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Yoon, Sungsoo. "Array-Based Measurements of Surface Wave Dispersion and Attenuation Using Frequency-Wavenumber Analysis." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7246.
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Surface wave methods have been used to determine dynamic properties of near-surface soils in geotechnical engineering for the past 50 years. Although the capabilities of engineering surface wave methods have improved in recent years due to several advances, several issues including (1) near-field effects, (2) combined active and passive measurements, and (3) accurate measurements of surface wave attenuation still require study to further improve the capabilities of modern surface wave methods.
Near-field effects have been studied for traditional surface wave methods with two receivers and several filtering criteria to mitigate the effects have been recommended. However, these filtering criteria are not applicable to surface wave methods with multiple receivers. Moreover, the criteria are not quantitatively based and do not account for different types of soil profiles, which strongly influence near-field effects. A new study of near-field effects on surface wave methods with multiple receivers was conducted with numerical and experimental methods. Two normalized parameters were developed to capture near-field effects. Quantitatively based near-field effect criteria for an ideal homogeneous half-space and three typical soil profiles are presented.
Combining active and passive surface wave measurements allows developing a shear wave velocity profile to greater depth without sacrificing the near-surface resolution offered by active measurements. Generally, active and passive measurements overlap in the frequency range from approximately 4 to 10 Hz, and there are often systematic differences between the two measurements. The systematic errors in active and passive surface wave methods were explored to explain and resolve the differences, allowing for a more accurate composite dispersion curve.
The accuracy of measured surface wave attenuation is improved by properly accounting for (1) geometric spreading, (2) near-field effects, and (3) ambient noise. In this study, a traditional estimation method and a frequency-wavenumber method utilizing sub-arrays were investigated using displacement data from numerical simulations, focusing on near-field and ambient noise effects. Detailed procedures for the frequency-wavenumber estimation method are developed based on a study of the primary factors affecting attenuation estimates. The two methods are also evaluated using experimental displacement data obtained from surface wave field measurements with three different arrays.
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Pasquet, Sylvain. "Apport des méthodes sismiques à l'hydrogéophysique : importance du rapport Vp/Vs et contribution des ondes de surface." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066495/document.
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La caractérisation et le monitoring des ressources en eau souterraine et des processus d'écoulement et de transport associés reposent principalement sur la mise en place de forages (piézomètres). Mais la variété des échelles auxquelles se déroulent ces processus et leur variabilité dans l'espace et dans le temps limitent l'interprétation des observations hydrogéologiques. Dans un tel contexte, l'hydrogéophysique fait appel aux méthodes de prospection géophysique afin, notamment, d'améliorer la très faible résolution spatiale des données de forage et de limiter leur caractère destructif. Parmi les outils géophysiques appliqués à l'hydrogéologie, les méthodes sismiques sont régulièrement utilisées à différentes échelles. Mais la réponse sismique dans le contexte de la caractérisation des aquifères reste complexe. L'interprétation des vitesses estimées est souvent délicate à cause de leur variabilité en fonction de la lithologie de l'aquifère (paramètres mécaniques intrinsèques et géométrie des milieux poreux le constituant, influence du degré de saturation, etc). La perméabilité du milieu a également un effet sur la géométrie d'un réservoir hydrologique dont les contours peuvent varier en espace comme en temps, compliquant ainsi l'interprétation des données sismiques.Les géophysiciens cherchent à pallier ces limites, notamment à travers l'étude conjointe des vitesses (Vp et Vs) des ondes compression (P) et de cisaillement (S), dont l'évolution est par définition fortement découplée en présence de fluides. D'un point de vue théorique, cette approche se révèle appropriée à la caractérisation de certains aquifères, en particulier grâce à l'estimation des rapports Vp/Vs ou du coefficient de Poisson. L'évaluation de ces rapports peut être pratiquée de manière systématique grâce à la tomographie sismique en réfraction en utilisant parallèlement ondes P et S. Mais d'un point de vue pratique, la mesure de Vs reste délicate à mettre en oeuvre car les ondes S sont souvent difficiles à générer et à identifier sur les enregistrements sismiques. Une alternative est proposée par l’estimation indirecte de Vs à partir de l’inversion de la dispersion des ondes de surface, réalisée à partir de mesures de la vitesse des ondes de surface contenues dans les enregistrements sismiques classiques. Bien que généralement proposée pour la caractérisation de milieux 1D, la prospection par ondes de surface peut être déployée le long de sections linéaires dans le but de reconstruire un modèle 2D de distribution des Vs du sous-sol.Une méthodologie a été mise au point afin d'exploiter simultanément et de façon optimale les ondes P et les ondes de surface à partir des mêmes enregistrements sismiques. Lors de sa mise en oeuvre sur le terrain, cette acquisition « en ondes P » a été systématiquement suivie d'une acquisition « en ondes SH » afin de comparer les vitesses Vs obtenues par analyse de la dispersion des ondes de surface et par tomographie en ondes SH. L'utilisation de cette méthodologie dans différents contextes géologiques et hydrogéologiques a permis d'estimer les variations latérales et temporelles du rapport Vp/Vs, en bon accord avec les informations géologiques a priori et les données géophysiques et piézométriques existantes. L'utilisation de l'interférométrie laser a également permis de mettre ces techniques de traitement en application sur des modèles physiques parfaitement contrôlés afin d'étudier la propagation des ondes élastiques dans des « analogues » réalistes de milieux poreux partiellement saturésCharacterisation and monitoring of groundwater resources and associated flow and transport processes mainly rely on the implementation of wells (piezometers). The interpretation of hydrogeological observations is however limited by the variety of scales at which these processes occur and by their variability in space and in time. In such a context, using geophysical methods often improves the very low spatial resolution of borehole data and limits their destructive nature. Among the geophysical tools applied to hydrogeology, seismic methods are commonly used at different scales. However, the seismic response in the context of aquifer characterisation remains complex. The interpretation of the estimated velocities is often difficult because of their variability depending on the aquifer lithology (intrinsic mechanical parameters and geometry of the constituting porous media, influence of the degree of saturation, etc). The permeability of the medium also affects the geometry of a hydrological reservoir whose contours may vary in space and in time, thus complicating the interpretation of seismic data. Geophysicists seek to overcome these limitations, especially through the joint study of compression (P-) and shear (S-) wave velocities (Vp and Vs), whose evolution is by definition highly decoupled in the presence of fluids. From a theoretical point of view, this approach proves suitable for the characterisation of aquifers, especially by estimating Vp/Vs or Poisson's ratio. The evaluation of these ratios can be systematically carried out with seismic refraction tomography using both P- and S-waves. However, retrieving Vs remains practically delicate because S-waves are usually difficult to generate and identify on seismic records. As an alternative, indirect estimation of Vs is commonly achieved thanks to surface-wave dispersion inversion, carried out from measurements of surface waves phase velocities contained in typical seismic records. Although it is usually proposed for the characterisation of 1D media, surface-wave prospecting can be deployed along linear sections in order to build 2D models of Vs distribution in the ground. A specific methodology has been developed for the combined and optimised exploitation of P- and surface waves present on single seismic records. When deployed on the field, this "P-wave" acquisition has been systematically followed by a "SH-wave" acquisition in order to compare Vs models obtained from surface-wave dispersion analysis and SH-wave refraction tomography. The use of this methodology in several geological and hydrogeological contexts allowed for estimating Vp/Vs ratio lateral and temporal variations in good agreement with a priori geological information and existing geophysical and piezometric data. Laser-based ultrasonic techniques were also proposed to put these processing techniques in practice on perfectly controlled physical models and study elastic wave propagation in partially saturated porous media
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Pasquet, Sylvain. "Apport des méthodes sismiques à l'hydrogéophysique : importance du rapport Vp/Vs et contribution des ondes de surface." Electronic Thesis or Diss., Paris 6, 2014. http://www.theses.fr/2014PA066495.
Full textAbstract:
La caractérisation et le monitoring des ressources en eau souterraine et des processus d'écoulement et de transport associés reposent principalement sur la mise en place de forages (piézomètres). Mais la variété des échelles auxquelles se déroulent ces processus et leur variabilité dans l'espace et dans le temps limitent l'interprétation des observations hydrogéologiques. Dans un tel contexte, l'hydrogéophysique fait appel aux méthodes de prospection géophysique afin, notamment, d'améliorer la très faible résolution spatiale des données de forage et de limiter leur caractère destructif. Parmi les outils géophysiques appliqués à l'hydrogéologie, les méthodes sismiques sont régulièrement utilisées à différentes échelles. Mais la réponse sismique dans le contexte de la caractérisation des aquifères reste complexe. L'interprétation des vitesses estimées est souvent délicate à cause de leur variabilité en fonction de la lithologie de l'aquifère (paramètres mécaniques intrinsèques et géométrie des milieux poreux le constituant, influence du degré de saturation, etc). La perméabilité du milieu a également un effet sur la géométrie d'un réservoir hydrologique dont les contours peuvent varier en espace comme en temps, compliquant ainsi l'interprétation des données sismiques.Les géophysiciens cherchent à pallier ces limites, notamment à travers l'étude conjointe des vitesses (Vp et Vs) des ondes compression (P) et de cisaillement (S), dont l'évolution est par définition fortement découplée en présence de fluides. D'un point de vue théorique, cette approche se révèle appropriée à la caractérisation de certains aquifères, en particulier grâce à l'estimation des rapports Vp/Vs ou du coefficient de Poisson. L'évaluation de ces rapports peut être pratiquée de manière systématique grâce à la tomographie sismique en réfraction en utilisant parallèlement ondes P et S. Mais d'un point de vue pratique, la mesure de Vs reste délicate à mettre en oeuvre car les ondes S sont souvent difficiles à générer et à identifier sur les enregistrements sismiques. Une alternative est proposée par l’estimation indirecte de Vs à partir de l’inversion de la dispersion des ondes de surface, réalisée à partir de mesures de la vitesse des ondes de surface contenues dans les enregistrements sismiques classiques. Bien que généralement proposée pour la caractérisation de milieux 1D, la prospection par ondes de surface peut être déployée le long de sections linéaires dans le but de reconstruire un modèle 2D de distribution des Vs du sous-sol.Une méthodologie a été mise au point afin d'exploiter simultanément et de façon optimale les ondes P et les ondes de surface à partir des mêmes enregistrements sismiques. Lors de sa mise en oeuvre sur le terrain, cette acquisition « en ondes P » a été systématiquement suivie d'une acquisition « en ondes SH » afin de comparer les vitesses Vs obtenues par analyse de la dispersion des ondes de surface et par tomographie en ondes SH. L'utilisation de cette méthodologie dans différents contextes géologiques et hydrogéologiques a permis d'estimer les variations latérales et temporelles du rapport Vp/Vs, en bon accord avec les informations géologiques a priori et les données géophysiques et piézométriques existantes. L'utilisation de l'interférométrie laser a également permis de mettre ces techniques de traitement en application sur des modèles physiques parfaitement contrôlés afin d'étudier la propagation des ondes élastiques dans des « analogues » réalistes de milieux poreux partiellement saturésCharacterisation and monitoring of groundwater resources and associated flow and transport processes mainly rely on the implementation of wells (piezometers). The interpretation of hydrogeological observations is however limited by the variety of scales at which these processes occur and by their variability in space and in time. In such a context, using geophysical methods often improves the very low spatial resolution of borehole data and limits their destructive nature. Among the geophysical tools applied to hydrogeology, seismic methods are commonly used at different scales. However, the seismic response in the context of aquifer characterisation remains complex. The interpretation of the estimated velocities is often difficult because of their variability depending on the aquifer lithology (intrinsic mechanical parameters and geometry of the constituting porous media, influence of the degree of saturation, etc). The permeability of the medium also affects the geometry of a hydrological reservoir whose contours may vary in space and in time, thus complicating the interpretation of seismic data. Geophysicists seek to overcome these limitations, especially through the joint study of compression (P-) and shear (S-) wave velocities (Vp and Vs), whose evolution is by definition highly decoupled in the presence of fluids. From a theoretical point of view, this approach proves suitable for the characterisation of aquifers, especially by estimating Vp/Vs or Poisson's ratio. The evaluation of these ratios can be systematically carried out with seismic refraction tomography using both P- and S-waves. However, retrieving Vs remains practically delicate because S-waves are usually difficult to generate and identify on seismic records. As an alternative, indirect estimation of Vs is commonly achieved thanks to surface-wave dispersion inversion, carried out from measurements of surface waves phase velocities contained in typical seismic records. Although it is usually proposed for the characterisation of 1D media, surface-wave prospecting can be deployed along linear sections in order to build 2D models of Vs distribution in the ground. A specific methodology has been developed for the combined and optimised exploitation of P- and surface waves present on single seismic records. When deployed on the field, this "P-wave" acquisition has been systematically followed by a "SH-wave" acquisition in order to compare Vs models obtained from surface-wave dispersion analysis and SH-wave refraction tomography. The use of this methodology in several geological and hydrogeological contexts allowed for estimating Vp/Vs ratio lateral and temporal variations in good agreement with a priori geological information and existing geophysical and piezometric data. Laser-based ultrasonic techniques were also proposed to put these processing techniques in practice on perfectly controlled physical models and study elastic wave propagation in partially saturated porous media
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Caplier, Clément. "Étude expérimentale des effets de hauteur d'eau finie, de confinement latéral et de courant sur les sillages et la résistance à l'avancement des navires." Thesis, Poitiers, 2015. http://www.theses.fr/2015POIT2315/document.
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Ce mémoire présente une étude expérimentale des effets de confinement de la voie d'eau et de courant sur les sillages et la résistance à l'avancement des navires. Deux formes de carènes génériques et représentatives de navires maritimes et fluviaux ont fait l'objet de mesures dans le bassin des carènes de l'Institut Pprime dans différentes configurations bathymétriques. Des méthodes de mesure de déformée de surface libre par moyens optiques stéréoscopiques ont été mises en place pour caractériser les sillages générés. L'étendue spatiale et la résolution des mesures optiques permet de mener une analyse fine du sillage dans l'espace spectral, afin de le décomposer en une composante hydrodynamique dans le champ proche de la carène et une composante ondulatoire dans le champ lointain. Les résultats obtenus dans une configuration de voie d'eau profonde mettent en évidence la non-linéarité des sillages. Les résultats obtenus dans une configuration de voie d'eau peu profonde mettent en avant une modification de la forme des sillages et une répartition différente de l'énergie entre les différents systèmes de vagues. L'influence de la forme et de la vitesse des navires sur l'amplitude de la réponse hydrodynamique et du courant de retour est mise en avant. Des mesures en présence de contre-courant montrent une augmentation de l'amplitude des vagues du sillage et un élargissement de la zone de réflexion au niveau des parois du canal. Des mesures de forces de traînée avec un dynamomètre donnent accès aux courbes de résistance dans chaque configuration. L'augmentation de la résistance à l'avancement en eau peu profonde est mise en parallèle avec l'augmentation de l'amplitude et de la longueur d'onde des ondes transversesThis thesis presents an experimental study of the effects of the waterway confinement and the current on ships wakes and drag. Two generic hulls representative of maritime and river ships have been studied in several bathymetric configurations in the towing tank of the Institut Pprime. Optical measurement methods based on a stereovision principle have been set up to measure the free surface deformations. The spatial extent and the resolution permits to lead a fine analysis of the wakes in the spectral space in order to decompose them into a hydrodynamic component and an undulatory component, respectively in the near-field and the far-field of the ship hull. The results obtained in a deep waterway configuration highlight the non-linearity of the ship wakes, which results in a modification of the shape of the envelop of the wave field in the real space. The results obtained in a shallow waterway configuration show a modification of the shape of the ship wakes and a different distribution of the energy between the wave systems. The influence of the shape and the speed of the ships on the amplitude of the hydrodynamic response and the return current is also identified. The comparison of the measurements in the presence of a counter-current with the results in calm water show an increase of the amplitude of the waves and an enlargement of the wash zone on the walls of the canal. Drag forces measurements with a multicomponent dynamometer give access to resistance curves for each configuration. The increase of the ship resistance in shallow water is put in parallel with the increase of the amplitude and the wavelength of the transverse waves
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Filippini, Andrea Gilberto. "Free surface flow simulation in estuarine and coastal environments : numerical development and application on unstructured meshes." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0404/document.
Full textAbstract:
Over the last decades, there has been considerable attention in the accurate mathematical modeling and numerical simulations of free surface wave propagation in near-shore environments. A physical correct description of the large scale phenomena, which take place in the shallow water region, must account for strong nonlinear and dispersive effects, along with the interaction with complex topographies. First, a study on the behavior in nonlinear regime of different Boussinesq-type models is proposed, showing the advantage of using fully-nonlinear models with respect to weakly-nonlinear and weakly dispersive models (commonly employed). Secondly, a new flexible strategy for solving the fully-nonlinear and weakly-dispersive Green-Naghdi equations is presented, which allows to enhance an existing shallow water code by simply adding an algebraic term to the momentum balance and is particularly adapted for the use of hybrid techniques for wave breaking. Moreover, the first discretization of the Green-Naghdi equations on unstructured meshes is proposed via hybrid finite volume/ finite element schemes. Finally, the models and the methods developed in the thesis are deployed to study the physical problem of bore formation in convergent alluvial estuary, providing the first characterization of natural estuaries in terms of bore inceptionCes dernières décennies, une attention particulière a été portée sur la modélisation mathématique et la simulation numérique de la propagation de vagues en environnements côtiers. Une description physiquement correcte des phénomènes à grande échelle, qui apparaissent dans les régions d'eau peu profonde, doit prendre en compte de forts effets non-linéaires et dispersifs, ainsi que l'interaction avec des bathymétries complexes. Dans un premier temps, une étude du comportement en régime non linéaire de différents modèles de type Boussinesq est proposée, démontrant l'avantage d'utiliser des modèles fortement non-linéaires par rapport à des modèles faiblement non-linéaires et faiblement dispersifs (couramment utilisés). Ensuite, une nouvelle approche flexible pour résoudre les équations fortement non-linéaires et faiblement dispersives de Green-Naghdi est présentée. Cette stratégie permet d'améliorer un code "shallow water" existant par le simple ajout d'un terme algébrique dans l'équation du moment et est particulièrement adapté à l'utilisation de techniques hybrides pour le déferlement des vagues. De plus, la première discrétisation des équations de Green-Naghdi sur maillage non structuré est proposée via des schémas hybrides Volume Fini/Élément Fini. Finalement, les modèles et méthodes développés dans la thèse sont appliqués à l'étude du problème physique de la formation du mascaret dans des estuaires convergents et alluviaux. Cela a amené à la première caractérisation d'estuaire naturel en terme d'apparition de mascaret
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Yen, Ta-Lung, and 嚴大龍. "Surface Wave Dispersion Analysis of Planar Corrugated Surfaces by Asymptotic Corrugations Boundary Conditions." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/13358769963814126866.
Full textAbstract:
碩士國立交通大學
電信工程研究所
100
Electromagnetic bandgap (EBG) structures had been widely investigated in literature in recent years, and the planar corrugated surface is one of them. In studying such structures, the dispersion and reflection phase diagrams are two of the most important characteristics. In this thesis, we will study how to retrieve the dispersion diagram of the corrugations accurately and rapidly. By an asymptotic method and the use of classical vector potentials, we can derive the characteristic equation, thereby obtaining the surface-wave dispersion diagram. To demonstrate its accuracy and quickness, the method we proposed will be compared to a full wave simulator and the transverse resonance technique (TRT), the latter being a traditional method for getting the dispersion diagram. Finally, we fabricated a corrugation, and measure its scattering parameters to indirectly verify the dispersion diagram obtained by the method we proposed. In traditional studies of corrugations, surface-wave propagations along only the two principal directions are considered, pertaining to the so-called soft and hard surfaces. In this thesis, we will further explore the situation whereby the wave propagates obliquely on the surface. By observing the dispersion diagram of the corrugations, we will notice its difference compared to normal periodic structures, and then explain the wave propagation properties on the corrugation surface. At the measurement stage, it is difficult to get the dispersion diagram directly, and usually the scattering parameters are used to explain the width and position in the frequency spectrum of the bandgaps. In the thesis, the relationship of the scattering parameters and wavenumbers are discussed, so that the measured scattering parameters can be transformed to the dispersion diagram effectively. So far we succeed in transforming the simulated scattering parameters to the dispersion diagram, and we hope this method can be applied to measured data in the future.
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Yeh, Ren-jie, and 葉仁傑. "Probing the Lateral Velocity Variations along the Manila Trench by Analysis of Surface Wave Dispersion." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/54621494925095429684.
Full textAbstract:
碩士國立中央大學
地球物理研究所
99
The Eurasian Plate subducts to the east beneath the Philippine Sea Plate along the Manila Trench. While the subducting slab is relatively cold and seismically fast as compared to ambient mantle, those of the mantle wedge often exhibit opposite characters resulting from partial melting of wet peridotite. As a result, we expect the existence of lateral velocity variations in slab-normal direction along the Manila trench corresponding to different depths of subducting slab. The objective of this study is thus to test the expectation by analyzing surface wave dispersions as observed by Broadband Array in Taiwan for Seismology (BATS). The fact that earthquake sources distribute on both sides of the Philippine archipelago makes the test feasible with distinct ray coverages to BATS’s stations. Surface wave dispersion refers to the different velocities of waves with different frequencies (periods), which can be explained by the longer period wave sampling deeper structures. In this study, we applied the Multiple Filter Technique (MFT) to analyze the Rayleigh wave dispersion curves. Results thus analyzed are then used for inversion of 1-D velocity model with the AK135 model as the initial, using the damped least-square inversion scheme. We determine the optimal damping factors by grid searching on the inversion results of synthetic waveforms, which are synthesized by FK method. The velocity inversion is done with the conventional surf96 codes. While velocities are overall fast for ray paths to the east of the Manila trench relative to those to the west, explained by the sampling of oceanic lithosphere versus continental one, there are indeed paths of low velocity anomalies corresponding to surface volcanic chains suggesting the effects of magma chambers. Future works include 2-D tomography studies to better resolve the velocity anomalies.
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Naskar, Tarun. "Testing of Ground Subsurface using Spectral and Multichannel Analysis of Surface Waves." Thesis, 2017. http://etd.iisc.ac.in/handle/2005/3775.
Full textAbstract:
Two surface wave testing methods, namely, (i) the spectral analysis of surface waves (SASW), and (ii) the multi-channel analysis of surface waves (MASW), form non-destructive and non-intrusive techniques for predicting the shear wave velocity profile of different layers of ground and pavement. These field testing tools are based on the dispersive characteristics of Rayleigh waves, that is, different frequency components of the surface wave travel at different velocities in layered media. The SASW and MASW testing procedure basically comprises of three different components: (i) field measurements by employing geophones/accelerometers, (ii) generating dispersion plots, and (iii) predicting the shear wave velocity profile based on an inversion analysis.
For generating the field dispersion plot, the complexities involved while doing the phase unwrapping calculations for the SASW technique, while performing the spectral calculations on the basis of two receivers’ data, makes it difficult to automate since it requires frequent manual judgment. In the present thesis, a new method, based on the sliding Fourier transform, has been introduced. The proposed method has been noted to be quite accurate, computationally economical and it generally overcomes the difficulties associated with the unwrapping of the phase difference between the two sensors’ data. In this approach, the unwrapping of the phase can be carried out without any manual intervention. As a result, an automation of the entire computational process to generate the dispersion plot becomes feasible. The method has been thoroughly validated by including a number of examples on the basis of surface wave field tests as well as synthetic test data.
While obtaining the dispersion image by using the MASW method, three different transformation techniques, namely, (i) the Park’s wavefield transform, (ii) the frequency (f) -wavenumber ( ) transform and (iii) the time intercept ( -phase slowness (p) transform have been utilized for generating the multimodal dispersion plots. The performance of these three different methods has been assessed by using synthetic as well as field data records obtained from a ground site by means of 48 geophones. Two-dimensional as well as three-dimensional dispersion plots were generated. The Park’s wavefield transformation method has been found to be especially advantageous since it neither requires a very high sampling rate nor an inclusion of the zero padding of the data in a wavenumber (distance) domain.
In the case of an irregular dispersive media, a proper analysis of the higher modes existing in the dispersion plots becomes essential for predicting the shear wave velocity profile of ground on the basis of surface wave tests. In such cases, the establishment of the predominant mode becomes quite significant. In the current investigation for Rayleigh wave propagation, the predominant mode has been computed by maximizing the normalized vertical displacements along the free surface. Eigenvectors computed from the thin layer approach (TLM) approach are analyzed to predict the corresponding predominant mode. It is noted that the establishment of the predominant mode becomes quite important where only two to six sensors are employed and the governing (predominant) modal dispersion curve is usually observed rather than several multiple modes which can otherwise be identified by using around 24 to 48 multiple sensors.
By using the TLM, it is, however, not possible to account for the exact contribution of the elastic half space in the dynamic stiffness matrix (DSM) approach. A method is suggested to incorporate the exact contribution of the elastic half space in the TLM. The numerical formulation is finally framed as a quadratic eigenvalue problem which can be easily solved by using the subroutine polyeig in MATLAB. The dispersion plots were generated for several chosen different ground profiles. The numerical results were found to match quite well with the data available from literature.
In order to address all the three different aspects of SASW and MASW techniques, a series of field tests were performed on five different ground sites. The ground vibrations were induced by means of (i) a 65 kg mass dropped freely from a height of 5 m, and (ii) by using a 20 pound sledge hammer. It was found that by using a 65 kg mass dropped from a height of 5 m, for stiffer sites, ground exploration becomes feasible even up to a depth of 50-80 m whereas for the softer sites the exploration depth is reduced to about 30 m. By using a 20 lb sledge hammer, the exploration depth is restricted to only 8-10 m due to its low impact energy.
Overall, it is expected that the work reported in the thesis will furnish useful guidelines for (i) performing the SASW and MASW field tests, (ii) generating dispersion plots/images, and (iii) predicting the shear wave velocity profile of the site based on an inversion analysis.
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Naskar, Tarun. "Testing of Ground Subsurface using Spectral and Multichannel Analysis of Surface Waves." Thesis, 2017. http://etd.iisc.ernet.in/2005/3775.
Full textAbstract:
Two surface wave testing methods, namely, (i) the spectral analysis of surface waves (SASW), and (ii) the multi-channel analysis of surface waves (MASW), form non-destructive and non-intrusive techniques for predicting the shear wave velocity profile of different layers of ground and pavement. These field testing tools are based on the dispersive characteristics of Rayleigh waves, that is, different frequency components of the surface wave travel at different velocities in layered media. The SASW and MASW testing procedure basically comprises of three different components: (i) field measurements by employing geophones/accelerometers, (ii) generating dispersion plots, and (iii) predicting the shear wave velocity profile based on an inversion analysis.
For generating the field dispersion plot, the complexities involved while doing the phase unwrapping calculations for the SASW technique, while performing the spectral calculations on the basis of two receivers’ data, makes it difficult to automate since it requires frequent manual judgment. In the present thesis, a new method, based on the sliding Fourier transform, has been introduced. The proposed method has been noted to be quite accurate, computationally economical and it generally overcomes the difficulties associated with the unwrapping of the phase difference between the two sensors’ data. In this approach, the unwrapping of the phase can be carried out without any manual intervention. As a result, an automation of the entire computational process to generate the dispersion plot becomes feasible. The method has been thoroughly validated by including a number of examples on the basis of surface wave field tests as well as synthetic test data.
While obtaining the dispersion image by using the MASW method, three different transformation techniques, namely, (i) the Park’s wavefield transform, (ii) the frequency (f) -wavenumber ( ) transform and (iii) the time intercept ( -phase slowness (p) transform have been utilized for generating the multimodal dispersion plots. The performance of these three different methods has been assessed by using synthetic as well as field data records obtained from a ground site by means of 48 geophones. Two-dimensional as well as three-dimensional dispersion plots were generated. The Park’s wavefield transformation method has been found to be especially advantageous since it neither requires a very high sampling rate nor an inclusion of the zero padding of the data in a wavenumber (distance) domain.
In the case of an irregular dispersive media, a proper analysis of the higher modes existing in the dispersion plots becomes essential for predicting the shear wave velocity profile of ground on the basis of surface wave tests. In such cases, the establishment of the predominant mode becomes quite significant. In the current investigation for Rayleigh wave propagation, the predominant mode has been computed by maximizing the normalized vertical displacements along the free surface. Eigenvectors computed from the thin layer approach (TLM) approach are analyzed to predict the corresponding predominant mode. It is noted that the establishment of the predominant mode becomes quite important where only two to six sensors are employed and the governing (predominant) modal dispersion curve is usually observed rather than several multiple modes which can otherwise be identified by using around 24 to 48 multiple sensors.
By using the TLM, it is, however, not possible to account for the exact contribution of the elastic half space in the dynamic stiffness matrix (DSM) approach. A method is suggested to incorporate the exact contribution of the elastic half space in the TLM. The numerical formulation is finally framed as a quadratic eigenvalue problem which can be easily solved by using the subroutine polyeig in MATLAB. The dispersion plots were generated for several chosen different ground profiles. The numerical results were found to match quite well with the data available from literature.
In order to address all the three different aspects of SASW and MASW techniques, a series of field tests were performed on five different ground sites. The ground vibrations were induced by means of (i) a 65 kg mass dropped freely from a height of 5 m, and (ii) by using a 20 pound sledge hammer. It was found that by using a 65 kg mass dropped from a height of 5 m, for stiffer sites, ground exploration becomes feasible even up to a depth of 50-80 m whereas for the softer sites the exploration depth is reduced to about 30 m. By using a 20 lb sledge hammer, the exploration depth is restricted to only 8-10 m due to its low impact energy.
Overall, it is expected that the work reported in the thesis will furnish useful guidelines for (i) performing the SASW and MASW field tests, (ii) generating dispersion plots/images, and (iii) predicting the shear wave velocity profile of the site based on an inversion analysis.
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Gaždová, Renata. "Využití a interpretace seismických povrchových vln v širokém oboru frekvencí." Doctoral thesis, 2012. http://www.nusl.cz/ntk/nusl-309478.
Full textAbstract:
Submitted Ph.D. thesis is concerning the application and interpretation of seismic surface waves in a broad range of frequencies and scales. Using surface waves as a supplement to the methods dealing with body waves seems to be worth the effort. Surface wave interpretation can be used to obtain new information about the studied medium and simultaneously it can overcome, in some cases, the limitations of other seismic techniques. Moreover, surface waves are usually present on measured records and hence for its usage it is not necessary to modify the standard measuring procedures. One of the results of this thesis is an original algorithm for dispersive waveform calculation. The program works in an arbitrary range of frequencies and scales. The input parameter for the calculation is the dispersion curve. In this point the algorithm differs from all other approaches used so far. Algorithm is based on a summation of frequency components with shifts corresponding to the velocity dispersion and distance. The resulting waveform only contains an individual dispersive wave of the selected mode, thus being particularly suitable for testing of methodologies for dispersive wave analysis. The algorithm was implemented into the program DISECA. Furthermore, a new procedure was designed to calculate the dispersion...
Book chapters on the topic "Surface-wave dispersion analysis"
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Dal Moro, Giancarlo. "Surface-Wave Analysis Beyond the Dispersion Curves: FVS." In Efficient Joint Analysis of Surface Waves and Introduction to Vibration Analysis: Beyond the Clichés, 55–72. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-46303-8_2.
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Vantassel, Joseph P., Brady R. Cox, Peter G. Hubbard, Michael Yust, Farnyuh Menq, Kyle Spikes, and Dante Fratta. "Effectiveness of Distributed Acoustic Sensing for Acquiring Surface Wave Dispersion Data Using Multichannel Analysis of Surface Waves." In Proceedings of the 4th International Conference on Performance Based Design in Earthquake Geotechnical Engineering (Beijing 2022), 1000–1008. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-11898-2_77.
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Schaeffer, A. J., and S. Lebedev. "Global Heterogeneity of the Lithosphere and Underlying Mantle: A Seismological Appraisal Based on Multimode Surface-Wave Dispersion Analysis, Shear-Velocity Tomography, and Tectonic Regionalization." In The Earth's Heterogeneous Mantle, 3–46. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-15627-9_1.
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"Dispersion analysis." In Surface Wave Methods for Near-Surface Site Characterization, 226–75. CRC Press, 2014. http://dx.doi.org/10.1201/b17268-8.
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"Inverse Dispersion by the Book." In Surface Wave Analysis for Near Surface Applications, 149–51. Elsevier, 2015. http://dx.doi.org/10.1016/b978-0-12-800770-9.15003-4.
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"Joint Analysis of Rayleigh-Wave Dispersion and P-Wave Refraction." In Surface Wave Analysis for Near Surface Applications, 159–61. Elsevier, 2015. http://dx.doi.org/10.1016/b978-0-12-800770-9.15005-8.
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van den Dool, Huug. "Conclusion." In Empirical Methods in Short-Term Climate Prediction. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780199202782.003.0017.
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In this book we have reviewed empirical methods in short-term climate prediction. We devoted a whole chapter to the design of two of these methods, Empirical Wave Propagation (EWP, Chapter 3) and Constructed Analogue (CA Chapter 7). Other methods of empirical prediction were listed in Chapter 8, with brief descriptions and examples and references. One chapter is devoted to EOFs, as such a diagnostic topic, but widely used in both prediction and diagnostics, and thoroughly debated for a few decades. Two brief chapters, written in support of the subsequent chapter, Teleconnections (Chapter 4), should make the discussion on EOFs more interesting, and the topic of effective degrees of freedom (Chapter 6) is indispensable when one wants to understand why and when natural analogues would work (or not), or how an analogue is constructed, or how any method using truncation works. Most chapters can be read largely in isolation, but connections can be made of course between chapters. EWP is claimed to be useful, if not essential, in understanding teleconnections. Dispersion experiments, featuring day-by-day time-scales, link the CA and EWP methods. Examples of El Nino boreal winter behavior can be found in (a) the examples of EOFs on global SST and 500 mb streamfunction (Chapter 5), (b) specification of surface weather from 500 mb streamfunction (Chapter 7), and (c) the ENSO correlation and compositing approach (Chapter 8). The noble pursuit of knowledge may have been as important in the choice of some material as any immediate prediction application. Chapter 9 is different, less research oriented, and more an eyewitness description of what goes on in the making of a seasonal prediction. This eyewitness account style spills over into Chapter 8 here and there, because in order to understand why certain methods have survived to this day some practicalities have to be understood. The closeness to real-time prediction throughout the book creates a sense of application. However, the application in this book does not go beyond the making of the forecast itself; we completely shied away from such topics as a cost/benefit analysis or decision-making process by, for example, a climate sensitive potato farmer or reservoir operator.
Conference papers on the topic "Surface-wave dispersion analysis"
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Li, Guifang, and S. R. Seshadri. "Finite beam analysis of nonlinear surface wave excitation." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.thhh3.
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Nonlinear surface and guided waves are potential candidates for information carriers in integrated all-optic signal processors. The instability of these waves determines whether they are available for application. The understanding of the mechanisms of distributive excitation of these waves is a prerequisite for using them. For nonlinear waves which degenerate into linear waves in the limit of small amplitudes, instability is deducible using Whitham's method, if the explicit power-dependent dispersion relation can be established. We present a perturbation method which is capable of analyzing the instability even if the powerdependent dispersion relation cannot be found or the waves have no linear analogy. We applied this method to the nonlinear surface wave supported by an interface between a nonlinear metal and vacuum, where power-dependent dispersion relation cannot be found, and subsequently developed a formalism governing the distributive grating and prism excitations of this wave. The self-modulation of this wave is found to be comparable with that of waves supported by Kerr type media.
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Tian, K., Z. C. Li, Y. Yang, J. P. Huang, N. Li, and X. L. Cao. "Dispersion Properties Analysis of Rayleigh Surface Wave in Viscoelastic Media." In 76th EAGE Conference and Exhibition 2014. Netherlands: EAGE Publications BV, 2014. http://dx.doi.org/10.3997/2214-4609.20140879.
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Socco, L. V., P. Bergamo, and F. Garofalo. "Surface Wave Dispersion Analysis - From Local 1D Models to Tomography." In 76th EAGE Conference and Exhibition - Workshops. Netherlands: EAGE Publications BV, 2014. http://dx.doi.org/10.3997/2214-4609.20140528.
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Hassan, W. "Numerical Analysis of the Rayleigh Wave Dispersion Due to Surface Roughness." In QUANTITATIVE NONDESTRUCTIVE EVALUATION. AIP, 2004. http://dx.doi.org/10.1063/1.1711633.
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Raab, T., T. Reinsch, P. Jousset, and C. M. Krawczyk. "Multi-station Analysis of Surface Wave Dispersion Using Distributed Acoustic Fiber Optic Sensing." In EAGE/DGG Workshop 2017. Netherlands: EAGE Publications BV, 2017. http://dx.doi.org/10.3997/2214-4609.201700164.
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Ivanov, Julian, Richard D. Miller, Sarah Morton, and Shelby Peterie. "DISPERSION-CURVE IMAGING CONSIDERATIONS WHEN USING MULTICHANNEL ANALYSIS OF SURFACE WAVE (MASW) METHOD." In Symposium on the Application of Geophysics to Engineering and Environmental Problems 2015. Society of Exploration Geophysicists and Environment and Engineering Geophysical Society, 2015. http://dx.doi.org/10.4133/sageep.28-079.
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Kaul, A., P. J. Bilsby, A. Misbah, and A. Abubakar. "Machine-Learning-Driven Dispersion Curve Picking for Surface-Wave Analysis, Modelling, and Inversion." In 82nd EAGE Annual Conference & Exhibition. European Association of Geoscientists & Engineers, 2020. http://dx.doi.org/10.3997/2214-4609.202010598.
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Kaul, A., P. Bilsby, A. Abubakar, and A. Misbah. "Machine-learning-driven dispersion curve picking for surface-wave analysis, modelling, and inversion." In First EAGE Conference on Machine Learning in Americas. European Association of Geoscientists & Engineers, 2020. http://dx.doi.org/10.3997/2214-4609.202084015.
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Kaul, A. "Machine-Learning-Driven Dispersion Curve Picking for Surface-Wave Analysis, Modelling, and Inversion." In EAGE/AAPG Digital Subsurface for Asia Pacific Conference. European Association of Geoscientists & Engineers, 2020. http://dx.doi.org/10.3997/2214-4609.202075041.
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Grosh, Karl, and Peter M. Pinsky. "Wave Component Analysis of Fluid-Loaded, Finite Cylindrical Shell Response." In ASME 1995 Design Engineering Technical Conferences collocated with the ASME 1995 15th International Computers in Engineering Conference and the ASME 1995 9th Annual Engineering Database Symposium. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/detc1995-0409.
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Abstract In this paper, the surface displacement response of a finite fluid-loaded shell and the resulting far field acoustic pressure are studied. A high resolution signal processing algorithm is applied to the surface displacement to estimate the constituent wave numbers and corresponding amplitudes for these wave components. This parameter estimation technique identifies the fluid-loaded cylinder’s complex dispersion relations from finite shell data; the dispersion relations consist of subsonic, leaky, evanescent and oscillatory-decaying wave-number loci. The identified results are compared to the analytic dispersion relations. The far field pressure radiated due to each wave-number component is computed allowing for the determination of important contributors to the far field response. For the frequencies studied, the subsonic wave dominates the far field response due to the finite length of the shell and large amplitude of this component. The supersonic components have the next largest contribution to the far field pressure.