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Sample records for anti-plane s-wave analytical

  1. Analytical solutions to general anti-plane shear problems in finite elasticity

    NASA Astrophysics Data System (ADS)

    Gao, David Yang

    2016-03-01

    This paper presents a pure complementary energy variational method for solving a general anti-plane shear problem in finite elasticity. Based on the canonical duality-triality theory developed by the author, the nonlinear/nonconvex partial differential equations for the large deformation problem are converted into an algebraic equation in dual space, which can, in principle, be solved to obtain a complete set of stress solutions. Therefore, a general analytical solution form of the deformation is obtained subjected to a compatibility condition. Applications are illustrated by examples with both convex and nonconvex stored strain energies governed by quadratic-exponential and power-law material models, respectively. Results show that the nonconvex variational problem could have multiple solutions at each material point, the complementary gap function and the triality theory can be used to identify both global and local extremal solutions, while the popular convexity conditions (including rank-one condition) provide mainly local minimal criteria and the Legendre-Hadamard condition (i.e., the so-called strong ellipticity condition) does not guarantee uniqueness of solutions. This paper demonstrates again that the pure complementary energy principle and the triality theory play important roles in finite deformation theory and nonconvex analysis.

  2. An analytical solution to separate P-waves and S-waves in the VSP wavefield

    SciTech Connect

    Amano, Hiroshi

    1994-12-31

    An analytical solution to separate P-waves and S-waves in the VSP wavefield is derived with combinations of the formal solution of a forward VSP modeling. Some practical applications of this method to synthetic seismograms and field data are investigated and evaluated. Little wave distortion is recognized and the weak wavefield masked by dominant wave trains can be extracted with this method. The decomposed wavefield is expressed in frequency-depth (f-z) domain as a linear combination of up to the third order differential of traces, which is approximated by trace difference sin the practical separation process. In general, five traces with single-component data are required in this process, but the same process is implemented with only three traces in the acoustic case. Two-trace extrapolation is applied to each edge of data gather in order to enhance the accuracy of trace difference. Since the formulas are developed in f-z domain, the influence of anelasticity is taken into account with simplicity and the calculation is carried out fast enough with the benefit of fast Fourier transform (FFT).

  3. Debonding of an elastic inhomogeneity of arbitrary shape in anti-plane shear

    NASA Astrophysics Data System (ADS)

    Wang, Xu; Yang, Moxuan; Schiavone, Peter

    2016-08-01

    We investigate the anti-plane shear problem of a curvilinear crack lying along the interface of an arbitrarily shaped elastic inhomogeneity embedded in an infinite matrix subjected to uniform stresses at infinity. Complex variable and conformal mapping techniques are used to derive an analytical solution in series form. The problem is first reduced to a non-homogeneous Riemann-Hilbert problem, the solution of which can be obtained by evaluating the associated Cauchy integral. A set of linear algebraic equations is obtained from the compatibility condition imposed on the resulting analytic function defined in the inhomogeneity and its Faber series expansion. Each of the unknown coefficients in the corresponding analytic functions can then be uniquely determined by solving the linear algebraic equations, which are written concisely in matrix form. The resulting analytical solution is then used to quantify the displacement jump across the debonded section of the interface as well as the traction distribution along the bonded section of the interface. In addition, our solution allows us to obtain mode-III stress intensity factors at the two crack tips. The solution to the anti-plane problem of a partially debonded elliptical inhomogeneity containing a confocal crack is also derived using a similar method.

  4. Teleseismic S wave microseisms.

    PubMed

    Nishida, Kiwamu; Takagi, Ryota

    2016-08-26

    Although observations of microseisms excited by ocean swells were firmly established in the 1940s, the source locations remain difficult to track. Delineation of the source locations and energy partition of the seismic wave components are key to understanding the excitation mechanisms. Using a seismic array in Japan, we observed both P and S wave microseisms excited by a severe distant storm in the Atlantic Ocean. Although nonlinear forcing of an ocean swell with a one-dimensional Earth model can explain P waves and vertically polarized S waves (SV waves), it cannot explain horizontally polarized S waves (SH waves). The precise source locations may provide a new catalog for exploring Earth's interior. PMID:27563094

  5. Anti-plane transverse waves propagation in nanoscale periodic layered piezoelectric structures.

    PubMed

    Chen, A-Li; Yan, Dong-Jia; Wang, Yue-Sheng; Zhang, Chuanzeng

    2016-02-01

    In this paper, anti-plane transverse wave propagation in nanoscale periodic layered piezoelectric structures is studied. The localization factor is introduced to characterize the wave propagation behavior. The transfer matrix method based on the nonlocal piezoelectricity continuum theory is used to calculate the localization factor. Additionally, the stiffness matrix method is applied to compute the wave transmission spectra. A cut-off frequency is found, beyond which the elastic waves cannot propagate through the periodic structure. The size effect or the influence of the ratio of the internal to external characteristic lengths on the cut-off frequency and the wave propagation behavior are investigated and discussed. PMID:26518526

  6. Crack Growth Mechanisms under Anti-Plane Shear in Composite Laminates

    NASA Astrophysics Data System (ADS)

    Horner, Allison Lynne

    The research conducted for this dissertation focuses on determining the mechanisms associated with crack growth in polymer matrix composite laminates subjected to anti-plane shear (mode III) loading. For mode III split-beam test methods were proposed, and initial evaluations were conducted. A single test method was selected for further evaluation. Using this test method, it was determined that the apparent mode III delamination toughness, GIIIc , depended on geometry, which indicated a true material property was not being measured. Transverse sectioning and optical microscopy revealed an array of transverse matrix cracks, or echelon cracks, oriented at approximately 45° and intersecting the plane of the delamination. Subsequent investigations found the echelon array formed prior to the onset of planar delamination advance and that growth of the planar delamination is always coupled to echelon array formation in these specimens. The evolution of the fracture surfaces formed by the echelon array and planar delamination were studied, and it was found that the development was similar to crack growth in homogenous materials subjected to mode III or mixed mode I-III loading, although the composite laminate architecture constrained the fracture surface development differently than homogenous materials. It was also found that, for split-beam specimens such as those used herein, applying an anti-plane shear load results in twisting of the specimen's uncracked region which gives rise to a mixed-mode I-III load condition. This twisting has been related to the apparent mode III toughness as well as the orientation of the transverse matrix cracks. A finite element model was then developed to study the mechanisms of initial echelon array formation. From this, it is shown that an echelon array will develop, but will become self-limiting prior to the onset of planar delamination growth.

  7. Uniform strain field inside a non-circular inhomogeneity with homogeneously imperfect interface in anisotropic anti-plane shear

    NASA Astrophysics Data System (ADS)

    Dai, Ming; Schiavone, Peter; Gao, Cun-Fa

    2016-06-01

    We re-examine the conclusion established earlier in the literature that in the presence of a homogeneously imperfect interface, the circular inhomogeneity is the only shape of inhomogeneity which can achieve a uniform internal strain field in an isotropic or anisotropic material subjected to anti-plane shear. We show that under certain conditions, it is indeed possible to design such non-circular inhomogeneities despite the limitation of a homogeneously imperfect interface. Our method proceeds by prescribing a uniform strain field inside a non-circular inhomogeneity via perturbations of the uniform strain field inside the analogous circular inhomogeneity and then subsequently identifying the corresponding (non-circular) shape via the use of a conformal mapping whose unknown coefficients are determined from a system of nonlinear equations. We illustrate our results with several examples. We note also that, for a given size of inhomogeneity, the minimum value of the interface parameter required to guarantee the desired uniform internal strain increases as the elastic constants of the inclusion approach those of the matrix. Finally, we discuss in detail the relationship between the curvature of the interface and the displacement jump across the interface in the design of such inhomogeneities.

  8. A meshfree local RBF collocation method for anti-plane transverse elastic wave propagation analysis in 2D phononic crystals

    NASA Astrophysics Data System (ADS)

    Zheng, Hui; Zhang, Chuanzeng; Wang, Yuesheng; Sladek, Jan; Sladek, Vladimir

    2016-01-01

    In this paper, a meshfree or meshless local radial basis function (RBF) collocation method is proposed to calculate the band structures of two-dimensional (2D) anti-plane transverse elastic waves in phononic crystals. Three new techniques are developed for calculating the normal derivative of the field quantity required by the treatment of the boundary conditions, which improve the stability of the local RBF collocation method significantly. The general form of the local RBF collocation method for a unit-cell with periodic boundary conditions is proposed, where the continuity conditions on the interface between the matrix and the scatterer are taken into account. The band structures or dispersion relations can be obtained by solving the eigenvalue problem and sweeping the boundary of the irreducible first Brillouin zone. The proposed local RBF collocation method is verified by using the corresponding results obtained with the finite element method. For different acoustic impedance ratios, various scatterer shapes, scatterer arrangements (lattice forms) and material properties, numerical examples are presented and discussed to show the performance and the efficiency of the developed local RBF collocation method compared to the FEM for computing the band structures of 2D phononic crystals.

  9. Supersonic crack growth in a solid of upturn stress?strain relation under anti-plane shear

    NASA Astrophysics Data System (ADS)

    Guo, Gaofeng; Yang, Wei; Huang, Y.

    2003-11-01

    This paper examines, from the prospect of continuum analysis, the possibility for a supersonic crack growth in a solid with an upturn stress-strain relation. The stress has a linear-upturn power-law relation with the strain, resulting in an elastic modulus, and consequently a wave speed, that increase with the strain. Though appearing to be "supersonic", the local wave speed in the crack tip vicinity of the solid with a sufficient upturn stress-strain relation exceeds the crack extension speed. A pre-request for such a supersonic crack growth is the storage of sufficient deformation energy within the solid to nurse the energy flux drawn to the crack tip that extends at an "apparent supersonic" speed. The idea is demonstrated for the simplest case, the anti-plane shear. We examine the steady-state supersonic crack growth in a hyperelastic material. The governing equation is elliptical in the crack tip vicinity but hyperbolic elsewhere. The boundary between two regions is determined with a certain extent. An asymptotic solution is constructed within the super-hardening zone. The solution connects to the hyperbolic radiation strips by weak discontinuity boundaries and to the pre-stressed frontal field by a strong discontinuity boundary.

  10. Chiral dynamics of S -wave baryon resonances

    NASA Astrophysics Data System (ADS)

    Long, Bingwei

    2016-07-01

    As the pion mass approaches a critical value mπ⋆ from below, an S -wave resonance crosses the pion-baryon threshold and becomes a bound state with arbitrarily small binding energy, thus driving the scattering length to diverge. I explore the consequences of chiral symmetry for the values of mπ close to mπ⋆. It turns out that chiral symmetry is crucial for an S -wave resonance to be able to stand very near the threshold and in the meantime to remain narrow, provided that the mass splitting is reasonably small. The effective range of pion-baryon scattering is unexpectedly large, proportional to 4 π fπ2/mπ3 when mπ is around mπ⋆. As a result, this unexpected large length scale causes universality relations to break down much sooner than naively expected.

  11. Structure of near-threshold s-wave resonances.

    PubMed

    Hyodo, Tetsuo

    2013-09-27

    We study the structure of two-body s-wave bound states as well as resonances in the threshold energy region. We focus on the single-channel scattering where the scattering length and the effective range are given by real numbers. It is shown that, in the energy region where the effective range expansion is valid, the properties of resonances are constrained only by the position of the pole. We find that the compositeness defined through the analytic continuation of the field renormalization constant is purely imaginary and normalized for resonances. We discuss the interpretation of this quantity by examining the structure of the hadron resonance Λc(2595) in the πΣc scattering. We show that the Λc(2595) resonance requires an unnaturally large effective range and hence it is not likely a πΣc molecule. PMID:24116769

  12. Structure of Near-Threshold s-Wave Resonances

    NASA Astrophysics Data System (ADS)

    Hyodo, Tetsuo

    2013-09-01

    We study the structure of two-body s-wave bound states as well as resonances in the threshold energy region. We focus on the single-channel scattering where the scattering length and the effective range are given by real numbers. It is shown that, in the energy region where the effective range expansion is valid, the properties of resonances are constrained only by the position of the pole. We find that the compositeness defined through the analytic continuation of the field renormalization constant is purely imaginary and normalized for resonances. We discuss the interpretation of this quantity by examining the structure of the hadron resonance Λc(2595) in the πΣc scattering. We show that the Λc(2595) resonance requires an unnaturally large effective range and hence it is not likely a πΣc molecule.

  13. Holographic s-wave condensate with nonlinear electrodynamics: A nontrivial boundary value problem

    NASA Astrophysics Data System (ADS)

    Banerjee, Rabin; Gangopadhyay, Sunandan; Roychowdhury, Dibakar; Lala, Arindam

    2013-05-01

    In this paper, considering the probe limit, we analytically study the onset of holographic s-wave condensate in the planar Schwarzschild-AdS background. Inspired by various low-energy features of string theory, in the present work we replace the conventional Maxwell action with a (nonlinear) Born-Infeld action which essentially corresponds to the higher-derivative corrections of the gauge fields. Based on a variational method which is commonly known as the Sturm-Liouville eigenvalue problem and considering a nontrivial asymptotic solution for the scalar field, we compute the critical temperature for the s-wave condensation. The results thus obtained analytically agree well with the numerical findings [J. Jing and S. Chen, Phys. Lett. B 686, 68 (2010)]. As a next step, we extend our perturbative technique to compute the order parameter for the condensation. Interestingly, our analytic results are found to be of the same order as the numerical values obtained earlier.

  14. Fault zone characterization using P- and S-waves

    NASA Astrophysics Data System (ADS)

    Wawerzinek, Britta; Buness, Hermann; Polom, Ulrich; Tanner, David C.; Thomas, Rüdiger

    2014-05-01

    Although deep fault zones have high potential for geothermal energy extraction, their real usability depends on complex lithological and tectonic factors. Therefore a detailed fault zone exploration using P- and S-wave reflection seismic data is required. P- and S-wave reflection seismic surveys were carried out along and across the eastern border of the Leinetal Graben in Lower Saxony, Germany, to analyse the structural setting, different reflection characteristics and possible anisotropic effects. In both directions the P-wave reflection seismic measurements show a detailed and complex structure. This structure was developed during several tectonic phases and comprises both steeply- and shallowly-dipping faults. In a profile perpendicular to the graben, a strong P-wave reflector is interpreted as shallowly west-dipping fault that is traceable from the surface down to 500 m depth. It is also detectable along the graben. In contrast, the S-waves show different reflection characteristics: There is no indication of the strong P-wave reflector in the S-wave reflection seismic measurements - neither across nor along the graben. Only diffuse S-wave reflections are observable in this region. Due to the higher resolution of S-waves in the near-surface area it is possible to map structures which cannot be detected in P-wave reflection seismic, e.g the thinning of the uppermost Jurassic layer towards the south. In the next step a petrophysical analysis will be conducted by using seismic FD modelling to a) determine the cause (lithological, structural, or a combination of both) of the different reflection characteristics of P- and S-waves, b) characterize the fault zone, as well as c) analyse the influence of different fault zone properties on the seismic wave field. This work is part of the gebo collaborative research programme which is funded by the 'Niedersächsisches Ministerium für Wissenschaft und Kultur' and Baker Hughes.

  15. Chromomagnetism, flavour symmetry breaking and S-wave tetraquarks

    NASA Astrophysics Data System (ADS)

    Buccella, F.; Høgaasen, H.; Richard, J.-M.; Sorba, P.

    2007-02-01

    The chromomagnetic interaction, with full account for flavour-symmetry breaking, is applied to S-wave configurations containing two quarks and two antiquarks. Phenomenological implications are discussed for light, charmed, charmed and strange, hidden-charm and double-charm mesons, and extended to their analogues with beauty.

  16. A simple method of predicting S-wave velocity

    USGS Publications Warehouse

    Lee, M.W.

    2006-01-01

    Prediction of shear-wave velocity plays an important role in seismic modeling, amplitude analysis with offset, and other exploration applications. This paper presents a method for predicting S-wave velocity from the P-wave velocity on the basis of the moduli of dry rock. Elastic velocities of water-saturated sediments at low frequencies can be predicted from the moduli of dry rock by using Gassmann's equation; hence, if the moduli of dry rock can be estimated from P-wave velocities, then S-wave velocities easily can be predicted from the moduli. Dry rock bulk modulus can be related to the shear modulus through a compaction constant. The numerical results indicate that the predicted S-wave velocities for consolidated and unconsolidated sediments agree well with measured velocities if differential pressure is greater than approximately 5 MPa. An advantage of this method is that there are no adjustable parameters to be chosen, such as the pore-aspect ratios required in some other methods. The predicted S-wave velocity depends only on the measured P-wave velocity and porosity. ?? 2006 Society of Exploration Geophysicists.

  17. Exotic s-wave superconductivity in alkali-doped fullerides

    NASA Astrophysics Data System (ADS)

    Nomura, Yusuke; Sakai, Shiro; Capone, Massimo; Arita, Ryotaro

    2016-04-01

    Alkali-doped fullerides ({{A}3}{{\\text{C}}60} with A  =  K, Rb, Cs) show a surprising phase diagram, in which a high transition-temperature ({{T}\\text{c}} ) s-wave superconducting state emerges next to a Mott insulating phase as a function of the lattice spacing. This is in contrast with the common belief that Mott physics and phonon-driven s-wave superconductivity are incompatible, raising a fundamental question on the mechanism of the high-{{T}\\text{c}} superconductivity. This article reviews recent ab initio calculations, which have succeeded in reproducing comprehensively the experimental phase diagram with high accuracy and elucidated an unusual cooperation between the electron-phonon coupling and the electron-electron interactions leading to Mott localization to realize an unconventional s-wave superconductivity in the alkali-doped fullerides. A driving force behind the exotic physics is unusual intramolecular interactions, characterized by the coexistence of a strongly repulsive Coulomb interaction and a small effectively negative exchange interaction. This is realized by a subtle energy balance between the coupling with the Jahn-Teller phonons and Hund’s coupling within the {{\\text{C}}60} molecule. The unusual form of the interaction leads to a formation of pairs of up- and down-spin electrons on the molecules, which enables the s-wave pairing. The emergent superconductivity crucially relies on the presence of the Jahn-Teller phonons, but surprisingly benefits from the strong correlations because the correlations suppress the kinetic energy of the electrons and help the formation of the electron pairs, in agreement with previous model calculations. This confirms that the alkali-doped fullerides are a new type of unconventional superconductors, where the unusual synergy between the phonons and Coulomb interactions drives the high-{{T}\\text{c}} superconductivity.

  18. Exotic s-wave superconductivity in alkali-doped fullerides.

    PubMed

    Nomura, Yusuke; Sakai, Shiro; Capone, Massimo; Arita, Ryotaro

    2016-04-20

    Alkali-doped fullerides (A3C60 with A = K, Rb, Cs) show a surprising phase diagram, in which a high transition-temperature (Tc) s-wave superconducting state emerges next to a Mott insulating phase as a function of the lattice spacing. This is in contrast with the common belief that Mott physics and phonon-driven s-wave superconductivity are incompatible, raising a fundamental question on the mechanism of the high-Tc superconductivity. This article reviews recent ab initio calculations, which have succeeded in reproducing comprehensively the experimental phase diagram with high accuracy and elucidated an unusual cooperation between the electron-phonon coupling and the electron-electron interactions leading to Mott localization to realize an unconventional s-wave superconductivity in the alkali-doped fullerides. A driving force behind the exotic physics is unusual intramolecular interactions, characterized by the coexistence of a strongly repulsive Coulomb interaction and a small effectively negative exchange interaction. This is realized by a subtle energy balance between the coupling with the Jahn-Teller phonons and Hund's coupling within the C60 molecule. The unusual form of the interaction leads to a formation of pairs of up- and down-spin electrons on the molecules, which enables the s-wave pairing. The emergent superconductivity crucially relies on the presence of the Jahn-Teller phonons, but surprisingly benefits from the strong correlations because the correlations suppress the kinetic energy of the electrons and help the formation of the electron pairs, in agreement with previous model calculations. This confirms that the alkali-doped fullerides are a new type of unconventional superconductors, where the unusual synergy between the phonons and Coulomb interactions drives the high-Tc superconductivity. PMID:26974650

  19. P and S wave delays caused by thermal plumes

    NASA Astrophysics Data System (ADS)

    Maguire, Ross; Ritsema, Jeroen; van Keken, Peter E.; Fichtner, Andreas; Goes, Saskia

    2016-05-01

    Many studies have sought to seismically image plumes rising from the deep mantle in order to settle the debate about their presence and role in mantle dynamics, yet the predicted seismic signature of realistic plumes remains poorly understood. By combining numerical simulations of flow, mineral-physics constraints on the relationships between thermal anomalies and wave speeds, and spectral-element method based computations of seismograms, we estimate the delay times of teleseismic S and P waves caused by thermal plumes. Wavefront healing is incomplete for seismic periods ranging from 10 s (relevant in traveltime tomography) to 40 s (relevant in waveform tomography). We estimate P wave delays to be immeasurably small (< 0.3 s). S wave delays are larger than 0.4 s even for S waves crossing the conduits of the thinnest thermal plumes in our geodynamic models. At longer periods (> 20 s), measurements of instantaneous phase misfit may be more useful in resolving narrow plume conduits. To detect S wave delays of 0.4-0.8 s and the diagnostic frequency dependence imparted by plumes, it is key to minimize the influence of the heterogeneous crust and upper mantle. We argue that seismic imaging of plumes will advance significantly if data from wide-aperture ocean-bottom networks were available since, compared to continents, the oceanic crust and upper mantle is relatively simple.

  20. P- and S-wave delays caused by thermal plumes

    NASA Astrophysics Data System (ADS)

    Maguire, Ross; Ritsema, Jeroen; van Keken, Peter E.; Fichtner, Andreas; Goes, Saskia

    2016-08-01

    Many studies have sought to seismically image plumes rising from the deep mantle in order to settle the debate about their presence and role in mantle dynamics, yet the predicted seismic signature of realistic plumes remains poorly understood. By combining numerical simulations of flow, mineral-physics constraints on the relationships between thermal anomalies and wave speeds, and spectral-element method based computations of seismograms, we estimate the delay times of teleseismic S and P waves caused by thermal plumes. Wave front healing is incomplete for seismic periods ranging from 10 s (relevant in traveltime tomography) to 40 s (relevant in waveform tomography). We estimate P-wave delays to be immeasurably small (<0.3 s). S-wave delays are larger than 0.4 s even for S waves crossing the conduits of the thinnest thermal plumes in our geodynamic models. At longer periods (>20 s), measurements of instantaneous phase misfit may be more useful in resolving narrow plume conduits. To detect S-wave delays of 0.4-0.8 s and the diagnostic frequency dependence imparted by plumes, it is key to minimize the influence of the heterogeneous crust and upper mantle. We argue that seismic imaging of plumes will advance significantly if data from wide-aperture ocean-bottom networks were available since, compared to continents, the oceanic crust and upper mantle are relatively simple.

  1. Bending AdS waves with new massive gravity

    NASA Astrophysics Data System (ADS)

    Ayón-Beato, Eloy; Giribet, Gaston; Hassaïne, Mokhtar

    2009-05-01

    We study AdS-waves in the three-dimensional new theory of massive gravity recently proposed by Bergshoeff, Hohm, and Townsend. The general configuration of this type is derived and shown to exhibit different branches, with different asymptotic behaviors. In particular, for the special fine tuning m2 = ±1/(2l2), solutions with logarithmic fall-off arise, while in the range m2 > -1/(2l2), spacetimes with Schrödinger isometry group are admitted as solutions. Spacetimes that are asymptotically AdS3, both for the Brown-Henneaux and for the weakened boundary conditions, are also identified. The metric function that characterizes the profile of the AdS-wave behaves as a massive excitation on the spacetime, with an effective mass given by meff2 = m2-1/(2l2). For the critical value m2 = -1/(2l2), the value of the effective mass precisely saturates the Breitenlohner-Freedman bound for the AdS3 space where the wave is propagating on. The analogies with the AdS-wave solutions of topologically massive gravity are also discussed. Besides, we consider the coupling of both massive deformations to Einstein gravity and find the exact configurations for the complete theory, discussing all the different branches exhaustively. One of the effects of introducing the Chern-Simons gravitational term is that of breaking the degeneracy in the effective mass of the generic modes of pure New Massive Gravity, producing a fine structure due to parity violation. Another effect is that the zoo of exact logarithmic specimens becomes considerably enlarged.

  2. s-Wave collisional frequency shift of a fermion clock.

    PubMed

    Hazlett, Eric L; Zhang, Yi; Stites, Ronald W; Gibble, Kurt; O'Hara, Kenneth M

    2013-04-19

    We report an s-wave collisional frequency shift of an atomic clock based on fermions. In contrast to bosons, the fermion clock shift is insensitive to the population difference of the clock states, set by the first pulse area in Ramsey spectroscopy, θ(1). The fermion shift instead depends strongly on the second pulse area θ(2). It allows the shift to be canceled, nominally at θ(2)=π/2, but correlations perturb the null to slightly larger θ(2). The frequency shift is relevant for optical lattice clocks and increases with the spatial inhomogeneity of the clock excitation field, naturally larger at optical frequencies. PMID:23679589

  3. On the relative scattering of P- and S-waves

    NASA Technical Reports Server (NTRS)

    Malin, P. E.; Phinney, R. A.

    1985-01-01

    Using a single-scattering approximation, equations for the scattering attenuation coefficients of P-body and S-body waves are derived. The results are discussed in the light of the energy-renormalization approaches of Wu (1980, 1982) and Sato (1982) to seismic wave scattering. Practical methods for calculating the scattering attenuation coefficients for various earth models are emphasized. The conversions of P-waves to S-waves and S-waves to P-waves are included in the theory. The earth models are assumed to be randomly inhomogeneous, with their properties known only through their average-wavenumber power spectra. The power spectra are approximated with piecewise constant functions, each segment of which contributes to the net frequency-dependent scattering attenuation coefficient. The smallest and largest wavenumbers of a segment can be plotted along with the wavevectors of the incident and scattered waves on a wavenumber diagram. This diagram gives a geometric interpretation for the frequency behavior associated with each spectral segment, including a transition peak that is due entirely to the wavenumber limits of the segment. For regions of the earth where the inhomogeneity spectra are concentrated in a band of wavenumbers, it should be possible to observe such a peak in the apparent attenuation of seismic waves. Both the frequency and distance limits on the accuracy of the theoretical results are given.

  4. Estimating Moho depth utilizing S-wave receiver functions

    NASA Astrophysics Data System (ADS)

    Ceylan, S.; Rychert, C.; Harmon, N.

    2014-12-01

    H-k stacking method [Zhu and Kanamori, 2000] is a widely used grid search technique for estimating the Moho depth (H) and Vp/Vs (k) beneath a given station. The H-k surface reaches a maximum when the optimum H and k values are used, which is assumed to be the average crustal structure beneath the seismic station. In general, the method is employed in conjunction with P-wave receiver functions. Here, we investigate the usability of H-k stacking method with S-to-P (Sp) conversions and S-wave reverberations within the crust, employing an extended multi-taper deconvolution. We apply the method to southern California, using data recorded between 1990-2011. We compare results with those of prior studies that used P-to-S (Ps) conversions [Zhu and Kanamori, 2000; Yan and Clayton, 2007], applying a smoothing length of 0.5 degrees to reflect lateral Sp sensitivity. P-waves have better potential to resolve lateral variations in Moho depth owing to the higher frequency content and the geometry of Ps ray path. Our results from Sp conversions are in broad agreement with those from Ps, affirming that S-wave receiver functions can be used in conjunction with the H-k stacking method. Consistent with the P-wave receiver function results, crust is thinner beneath the central Transverse Range (30 km) with respect to eastern Transverse Range (33 km) and Peninsular Region (35 km). Our Moho depth observations (35 km) are more compatible with those of Yan and Clayton [2007] (~35 km) than Zhu and Kanamori [2000] (~30 km) beneath Sierra Nevada, most probably due to a larger data set this study and Yan and Clayton [2007] use. Also, results from this study are deeper than those from Ps for the Salton Trough (30-35 km vs. 25 km). In this case, broad receiver function waveform characteristics suggest a more gradual impedance change across the Moho discontinuity and/or a multi-layered crust. We suggest that a combination of P- and S-wave receiver functions can yield more robust crustal thickness

  5. Interaction of a screw dislocation with a nano-sized, arbitrarily shaped inhomogeneity with interface stresses under anti-plane deformations.

    PubMed

    Wang, Xu; Schiavone, Peter

    2014-10-01

    We propose an elegant and concise general method for the solution of a problem involving the interaction of a screw dislocation and a nano-sized, arbitrarily shaped, elastic inhomogeneity in which the contribution of interface/surface elasticity is incorporated using a version of the Gurtin-Murdoch model. The analytic function inside the arbitrarily shaped inhomogeneity is represented in the form of a Faber series. The real periodic function arising from the contribution of the surface mechanics is then expanded as a Fourier series. The resulting system of linear algebraic equations is solved through the use of simple matrix algebra. When the elastic inhomogeneity represents a hole, our solution method simplifies considerably. Furthermore, we undertake an analytical investigation of the challenging problem of a screw dislocation interacting with two closely spaced nano-sized holes of arbitrary shape in the presence of surface stresses. Our solutions quite clearly demonstrate that the induced elastic fields and image force acting on the dislocation are indeed size-dependent. PMID:25294965

  6. S-wave velocity structure in the SE Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Cai, Yan; Wu, Jianping; Wang, Weilai; Fang, Lihua; Fan, Liping

    2016-06-01

    We use observations recorded by 23 permanent and 99 temporary stations in the SE Tibetan plateau to obtain the S-wave velocity structure along two profiles by applying joint inversion with receiver functions and surface waves. The two profiles cross West Yunnan block (WYB), the Central Yunnan sub-block (CYB), South China block (SCB), and Nanpanjiang basin (NPB). The profile at ~25°N shows that the Moho interface in the CYB is deeper than those in the WYB and the NPB, and the topography and Moho depth have clear correspondence. Beneath the Xiaojiang fault zone (XJF), there exists a crustal low-velocity zone (LVZ), crossing the XJF and expanding eastward into the SCB. The NPB is shown to be of relatively high velocity. We speculate that the eastward extrusion of the Tibetan plateau may pass through the XJF and affect its eastern region, and is resisted by the rigid NPB, which has high velocity. This may be the main cause of the crustal thickening and uplift of the topography. In the Tengchong volcanic area, the crust is shown to have alternate high- and low-velocity layers, and the upper mantle is shown to be of low velocity. We consider that the magma which exists in the crust is from the upper mantle and that the complex crustal velocity structure is related to magmatic differentiation. Between the Tengchong volcanic area and the XJF, the crustal velocity is relatively high. Combining these observations with other geophysical evidence, it is indicated that rock strength is high and deformation is weak in this area, which is why the level of seismicity is quite low. The profile at ~23°N shows that the variation of the Moho depth is small from the eastern rigid block to the western active block with a wide range of LVZs. We consider that deformation to the south of the SE Tibetan Plateau is weak.

  7. Neutron capture in s-wave resonances of nickel-64

    SciTech Connect

    Wisshak, K.; Fabbri, F.; Kappeler, F.; Macklin, R.L.; Reffo, G.

    1984-05-01

    The neutron capture widths of the s-wave resonances at 13.9 and 33.8 keV in /sup 64/Ni have been determined using a setup with extremely low neutron sensitivity completely different from all previous experiments on this isotope. This feature is important because these resonances exhibit a very large scattering-to-capture ratio. A pulsed 3-MV Van de Graaff accelerator and a kinematically collimated neutron beam, produced via the /sup 7/Li(p,n) reaction, was used in the experiments. Capture gamma rays were observed by three Moxon-Rae detectors with a graphite, a bismuth-graphite, and a bismuth converter, respectively. The samples were positioned at a neutron flight path of only 6 to 8 cm. Thus, events due to capture of resonance-scattered neutrons in the detectors or in surrounding materials are completely discriminated by their additional time of flight. The short flight path and the high neutron flux at the sample position allowed for a signal-to-background ratio of approximately unity even for the broad resonance at 33.8 keV. The data obtained with the individual detectors were corrected for the efficiency of the different converter materials. For that purpose, detailed theoretical calculations of the capture gamma-ray spectra of the measured isotope and of gold, which was used as a standard, were performed. The final radiative widths are GAMMA..gamma.. (13.9 keV) = 1.01 + or - 0.07 eV and GAMMA..gamma.. (33.8 keV) = 1.16 + or - 0.08 eV, considerably smaller than the rough estimates obtained in previous work.

  8. S-wave velocity structure in the SE Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Cai, Yan; Wu, Jianping; Wang, Weilai; Fang, Lihua; Fan, Liping

    2016-05-01

    We use observations recorded by 23 permanent and 99 temporary stations in the SE Tibetan plateau to obtain the S-wave velocity structure along two profiles by applying joint inversion with receiver functions and surface waves. The two profiles cross West Yunnan block (WYB), the Central Yunnan sub-block (CYB), South China block (SCB), and Nanpanjiang basin (NPB). The profile at ~25°N shows that the Moho interface in the CYB is deeper than those in the WYB and the NPB, and the topography and Moho depth have clear correspondence. Beneath the Xiaojiang fault zone (XJF), there exists a crustal low-velocity zone (LVZ), crossing the XJF and expanding eastward into the SCB. The NPB is shown to be of relatively high velocity. We speculate that the eastward extrusion of the Tibetan plateau may pass through the XJF and affect its eastern region, and is resisted by the rigid NPB, which has high velocity. This may be the main cause of the crustal thickening and uplift of the topography. In the Tengchong volcanic area, the crust is shown to have alternate high- and low-velocity layers, and the upper mantle is shown to be of low velocity. We consider that the magma which exists in the crust is from the upper mantle and that the complex crustal velocity structure is related to magmatic differentiation. Between the Tengchong volcanic area and the XJF, the crustal velocity is relatively high. Combining these observations with other geophysical evidence, it is indicated that rock strength is high and deformation is weak in this area, which is why the level of seismicity is quite low. The profile at ~23°N shows that the variation of the Moho depth is small from the eastern rigid block to the western active block with a wide range of LVZs. We consider that deformation to the south of the SE Tibetan Plateau is weak.

  9. Majorana modes in a topological insulator/s-wave superconductor heterostructure

    PubMed Central

    Li, Zheng-Zao; Zhang, Fu-Chun; Wang, Qiang-Hua

    2014-01-01

    In a recent experiment, signatures of Majorana fermion (MF) were found in the vortex core threading a heterostructure composed of n layers of topological insulator (TI) deposited on a bulk s-wave superconductor. Here we provide strong theoretical support to the experiment. First, we demonstrate that MF modes appear on both top and bottom layers of TI, and are well separated for n ~ 6. The top MF becomes more extended with increasing n, in agrement with the experiment. Second, we show both analytically and numerically that right at the vortex core the MF mode is always accompanied by another low energy bound state, leading to a zero-bias peak plus a side peak in the local density of states (LDOS) therein. However, a local scalar impurity at the core can wipe out the accompanying side-peak state while leaving the zero-energy MF mode intact. Consequently the LDOS becomes symmetric about the fermi level, and the peak does not branch near the vortex core, in agreement with the experiment. Finally but unfortunately, while the MF is extremely stable against a single local impurity, the stability in terms of the critical impurity strength is reduced drastically for a moderate concentration (e.g., 10%) of impurities. PMID:25219507

  10. Predicting S-wave velocities for unconsolidated sediments at low effective pressure

    USGS Publications Warehouse

    Lee, Myung W.

    2010-01-01

    Accurate S-wave velocities for shallow sediments are important in performing a reliable elastic inversion for gas hydrate-bearing sediments and in evaluating velocity models for predicting S-wave velocities, but few S-wave velocities are measured at low effective pressure. Predicting S-wave velocities by using conventional methods based on the Biot-Gassmann theory appears to be inaccurate for laboratory-measured velocities at effective pressures less than about 4-5 megapascals (MPa). Measured laboratory and well log velocities show two distinct trends for S-wave velocities with respect to P-wave velocity: one for the S-wave velocity less than about 0.6 kilometer per second (km/s) which approximately corresponds to effective pressure of about 4-5 MPa, and the other for S-wave velocities greater than 0.6 km/s. To accurately predict S-wave velocities at low effective pressure less than about 4-5 MPa, a pressure-dependent parameter that relates the consolidation parameter to shear modulus of the sediments at low effective pressure is proposed. The proposed method in predicting S-wave velocity at low effective pressure worked well for velocities of water-saturated sands measured in the laboratory. However, this method underestimates the well-log S-wave velocities measured in the Gulf of Mexico, whereas the conventional method performs well for the well log velocities. The P-wave velocity dispersion due to fluid in the pore spaces, which is more pronounced at high frequency with low effective pressures less than about 4 MPa, is probably a cause for this discrepancy.

  11. Complex seismic amplitude inversion for P-wave and S-wave quality factors

    NASA Astrophysics Data System (ADS)

    Zong, Zhaoyun; Yin, Xingyao; Wu, Guochen

    2015-07-01

    Stratum quality factors (P-wave and S-wave quality factors, Qp and Qs) have gradually been utilized in the study of physical state of crust and uppermost mantle, tectonic evolution, hydrogeololgy, gas hydrates, petroleum exploration, etc. Different opinions of the seismic attenuation mechanism result in various approaches to estimate the P-wave and S-wave quality factors. Considering the viscoelasticity of the underground medium, the constitutive matrix of the Earth medium is written as the superposition of homogeneous background medium, elastic perturbation medium and viscoelastic perturbation medium. Under the hypothesis of Born integral and stationary phase approximation, the seismic reflectivity is initially raised in terms of P-wave and S-wave moduli, density, P-wave and S-wave quality factors. Furthermore, incorporating the complex seismic traces with the seismic wavelets at different offsets, a two-step inversion approach is proposed to estimate the P-wave and S-wave quality factors. The AVO/AVA Bayesian inversion approach is suggested to estimate the P-wave modulus and S-wave modulus with the real component of the pre-stack seismic data initially. Taking the estimated P-wave and S-wave moduli as prior information, the P-wave and S-wave quality factors are further estimated with the imaginary component of the complex pre-stack seismic data, which is the quadrature of the original data. Finally, synthetic examples demonstrate that the proposed approach is able to estimate P-wave and S-wave quality factors stably and properly, and two field data examples demonstrate that the proposed approach may work as an efficient approach to fluid identification.

  12. Constraining depth range of S wave velocity decrease after large earthquakes near Parkfield, California

    NASA Astrophysics Data System (ADS)

    Wu, Chunquan; Delorey, Andrew; Brenguier, Florent; Hadziioannou, Celine; Daub, Eric G.; Johnson, Paul

    2016-06-01

    We use noise correlation and surface wave inversion to measure the S wave velocity changes at different depths near Parkfield, California, after the 2003 San Simeon and 2004 Parkfield earthquakes. We process continuous seismic recordings from 13 stations to obtain the noise cross-correlation functions and measure the Rayleigh wave phase velocity changes over six frequency bands. We then invert the Rayleigh wave phase velocity changes using a series of sensitivity kernels to obtain the S wave velocity changes at different depths. Our results indicate that the S wave velocity decreases caused by the San Simeon earthquake are relatively small (~0.02%) and access depths of at least 2.3 km. The S wave velocity decreases caused by the Parkfield earthquake are larger (~0.2%), and access depths of at least 1.2 km. Our observations can be best explained by material damage and healing resulting mainly from the dynamic stress perturbations of the two large earthquakes.

  13. Comment on ``Spectroscopic factors for bound s-wave states derived from neutron scattering lengths''

    NASA Astrophysics Data System (ADS)

    Barker, F. C.

    1997-12-01

    The procedure proposed by Mohr et al. [Phys. Rev. C 55, 1591 (1997)] for extracting the spectroscopic factor for a bound s-wave neutron state from the scattering length appears to be of doubtful validity and accuracy.

  14. Determination of S-wave slowness from a linear array of borehole receivers

    NASA Astrophysics Data System (ADS)

    Eisner, Leo; Fischer, Tomáš; Rutledge, James T.

    2009-01-01

    Locations of seismic events from a linear array of receivers may require determination of slowness vectors of arriving waves. In an isotropic medium, P waves are polarized along the slowness vector, which enables direct determination of backazimuth (i.e. azimuth to a source from a receiver) from P-wave polarization. In contrast, S waves usually have much larger signal-to-noise ratio than P waves, but are polarized in a plane perpendicular to their slowness vectors, which prevents direct determination of their backazimuth. We have developed a novel technique to determine the slowness vector of S waves detected in a linear array of receivers in an isotropic medium. We combine the S-wave polarization measurement with the derivative of the S-wave travel times along the array to obtain the full slowness vector and backazimuth. The proposed method allows one to determine direction to sources of seismic events from a single linear array of receivers, using only S waves. This technique is not affected by SV waves, which is shown by a test on a synthetic data set. We also test the method on two real microseismic data sets from hydraulic fracturing treatments and show that it outperforms the backazimuth determination from P waves and from horizontal polarization of S waves.

  15. Site-effect estimations for Taipei Basin based on shallow S-wave velocity structures

    NASA Astrophysics Data System (ADS)

    Chen, Ying-Chi; Huang, Huey-Chu; Wu, Cheng-Feng

    2016-03-01

    Shallow S-wave velocities have been widely used for earthquake ground-motion site characterization. Thus, the S-wave velocity structures of Taipei Basin, Taiwan were investigated using array records of microtremors at 15 sites (Huang et al., 2015). In this study, seven velocity structures are added to the database describing Taipei Basin. Validity of S-wave velocity structures are first examined using the 1D Haskell method and well-logging data at the Wuku Sewage Disposal Plant (WK) borehole site. Basically, the synthetic results match well with the observed data at different depths. Based on S-wave velocity structures at 22 sites, theoretical transfer functions at five different formations of the sedimentary basin are calculated. According to these results, predominant frequencies for these formations are estimated. If the S-wave velocity of the Tertiary basement is assumed to be 1000 m/s, the predominant frequencies of the Quaternary sediments are between 0.3 Hz (WUK) and 1.4 Hz (LEL) in Taipei Basin while the depths of sediments between 0 m (i.e. at the edge of the basin) and 616 m (i.e. site WUK) gradually increase from southeast to northwest. Our results show good agreement with available geological and geophysical information.

  16. Identification and mitigation of T-S waves using localized dynamic surface modification

    NASA Astrophysics Data System (ADS)

    Amitay, Michael; Tuna, Burak A.; Dell'Orso, Haley

    2016-06-01

    The control of transition from a laminar to a turbulent flow over a flat plate using localized dynamic surface modifications was explored experimentally in Rensselaer Polytechnic Institute's subsonic wind tunnel. Dynamic surface modification, via a pair of Piezoelectrically Driven Oscillating Surface (PDOS) actuators, was used to excite and control the T-S wave over a flat plate. Creating an upstream, localized small disturbance at the most amplified frequency of fact = 250 Hz led to phase-locking the T-S wave. This enabled observation of the excited T-S wave using phase-locked stereoscopic particle image velocimetry. The growth of the T-S wave as it moved downstream was also measured using this technique (25% growth over four wavelengths of the excited wave). Activation of a downstream PDOS actuator (in addition to the upstream PDOS) at the appropriate amplitude and phase shift resulted in attenuation of the peak amplitude of the coherent velocity fluctuations (by up to 68%) and a substantial reduction of the degree of coherence of the T-S wave. Since the PDOS actuators used in this work were localized, the effect of the control strategy was confined to the region directly downstream of the PDOS actuator.

  17. Holographic s-wave condensation and Meissner-like effect in Gauss-Bonnet gravity with various non-linear corrections

    NASA Astrophysics Data System (ADS)

    Dey, Shirsendu; Lala, Arindam

    2015-03-01

    In this paper we have studied the onset of holographic s-wave condensate in the (4 + 1) dimensional planar Gauss-Bonnet-AdS black hole background with several non-linear corrections to the gauge field. In the probe limit, performing explicit analytic computations, with and without magnetic field, we found that these higher order corrections indeed affect various quantities characterizing the holographic superconductors. Also, performing a comparative study of the two non-linear electrodynamics it has been shown that the exponential electrodynamics has stronger effects on the formation of the scalar hair. We observe that our results agree well with those obtained numerically (Zhao et al., 2013).

  18. Kondo physics in the Josephon junction with DIII-class topological and s-wave superconductors

    NASA Astrophysics Data System (ADS)

    Gao, Z.; Gong, W. J.

    2015-12-01

    We discuss the Kondo effect in the Josephson junction formed by the indirect coupling between a one-dimensional DIII-class topological and s-wave superconductors via a quantum dot. By performing the Schrieffer-Wolff transformation, we find that the single-electron occupation in the quantum dot induces various correlation modes, such as the Kondo and singlet-triplet correlations between the quantum dot and the s-wave superconductor and the spin-exchange correlation between the dot and Majorana doublet. Also, it modifies the Josephson effect by introducing the high-order anisotropic Kondo-like correlation and extra spin-exchange correlations. However, the Kondo temperature is still governed by the antiferromagnetic correlation between the dot and s-wave superconductor. We believe that this work shows the fundamental property of the DIII-class topological superconductor.

  19. Three-dimensional P and S wave velocity structure of Redoubt Volcano, Alaska

    USGS Publications Warehouse

    Benz, H.M.; Chouet, B.A.; Dawson, P.B.; Lahr, J.C.; Page, R.A.; Hole, J.A.

    1996-01-01

    The three-dimensional P and S wave structure of Redoubt Volcano, Alaska, and the underlying crust to depths of 7-8 km is determined from 6219 P wave and 4008 S wave first-arrival times recorded by a 30-station seismograph network deployed on and around the volcano. First-arrival times are calculated using a finite-difference technique, which allows for flexible parameterization of the slowness model and easy inclusion of topography and source-receiver geometry. The three-dimensional P wave velocity structure and hypocenters are determined simultaneously, while the three-dimensional S wave velocity model is determined using the relocated seismicity and an initial S wave velocity model derived from the P wave velocity model assuming an average Vp/Vs ratio of 1.78. Convergence is steady with approximately 73% and 52% reduction in P and S wave arrival time RMS, respectively, after 10 iterations. The most prominent feature observed in the three-dimensional velocity models derived for both P and S waves is a relative low-velocity, near-vertical, pipelike structure approximately 1 km in diameter that extends from 1 to 6 km beneath sea level. This feature aligns axially with the bulk of seismicity and is interpreted as a highly fractured and altered zone encompassing a magma conduit. The velocity structure beneath the north flank of the volcano between depths of 1 and 6 km is characterized by large lateral velocity variations. High velocities within this region are interpreted as remnant dikes and sills and low velocities as regions along which magma migrates. No large low-velocity body suggestive of a magma chamber is resolved in the the upper 7-8 km of the crust.

  20. Lattice QCD studies of s-wave meson-baryon interactions

    SciTech Connect

    Ikeda, Yoichi

    2011-10-21

    We study the s-wave KN interactions in the isospin I = 0, 1 channels and associated exotic state {Theta}{sup +} from 2+1 flavor full lattice QCD simulation for relatively heavy quark mass corresponding to m{sub {pi}} = 871 MeV. The s-wave KN potentials are obtained from the Bethe-Salpeter amplitudes. Potentials in both channels reveal short range repulsions: Strength of the repulsion is stronger in the I = 1 potential. The I = 0 potential is found to have attractive well at mid range. The KN scattering phase shifts are calculated and compared with the experimental data.

  1. Anomalous fluctuations of s-wave reduced neutron widths of 192,194Pt resonances

    SciTech Connect

    Koehler, Paul Edward; Becvar, F.; Krticka, Milan; Harvey, John A; Guber, Klaus H

    2010-01-01

    We obtained an unprecedentedly large number of s-wave neutron widths through R-matrix analysis of neutron cross-section measurements on enriched Pt samples. Careful analysis of these data rejects the validity of the Porter-Thomas distribution with a statistical significance of at least 99.997%.

  2. Electron-impact excitation-autoionization of helium in the S-wave limit

    SciTech Connect

    Horner, Daniel A.; McCurdy, C. William; Rescigno, Thomas N.

    2004-10-01

    Excitation of the autoionizing states of helium by electron impact is shown in calculations in the s-wave limit to leave a clear signature in the singly differential cross section for the (e,2e) process. It is suggested that such behavior should be seen generally in (e,2e) experiments on atoms that measure the single differential cross section.

  3. S-wave velocity measurements applied to the seismic microzonation of Basel, Upper Rhine Graben

    NASA Astrophysics Data System (ADS)

    Havenith, Hans-Balder; Fäh, Donat; Polom, Ulrich; Roullé, Agathe

    2007-07-01

    An extensive S-wave velocity survey had been carried out in the frame of a recent seismic microzonation study of Basel and the border areas between Switzerland, France and Germany. The aim was to better constrain the seismic amplification potential of the surface layers. The survey included single station (H/V spectral ratios) and ambient vibration array measurements carried out by the Swiss team, as well as active S-wave velocity measurements performed by the German and French partners. This paper is focused on the application of the array technique, which consists in recording ambient vibrations with a number of seismological stations. Several practical aspects related to the field measurements are outlined. The signal processing aims to determine the dispersion curves of surface waves contained in the ambient vibrations. The inversion of the dispersion curve provides a 1-D S-wave velocity model for the investigated site down to a depth related to the size of the array. Since the size of arrays is theoretically not limited, arrays are known to be well adapted for investigations in deep sediment basins, such as the Upper Rhine Graben including the area of the city of Basel. In this region, 27 array measurements with varying station configurations have been carried out to determine the S-wave velocity properties of the geological layers down to a depth of 100-250 m. For eight sites, the outputs of the array measurements have been compared with the results of the other investigations using active sources, the spectral analysis of surface waves (SASW) and S-wave reflection seismics. Borehole information available for a few sites could be used to calibrate the geophysical measurements. By this comparison, the advantages and disadvantages of the array method and the other techniques are outlined with regard to the effectiveness of the methods and the required investigation depth. The dispersion curves measured with the arrays and the SASW technique were also combined

  4. P-wave and S-wave Tomography for Characterizing an Impoundment Dam

    NASA Astrophysics Data System (ADS)

    Link, C. A.; Betterly, S. J.; Romero, S.

    2005-05-01

    A data set consisting of vertical and shear component seismic data was recorded on the crest of an impoundment dam. The data were recorded for the purpose of characterizing the integrity of the dam before transferal of the property to the public domain. Cone penetrometer results were also available for comparison. Four sets of 24 channels were used to record data from 3-component spiked geophones and vertical component data from gimbaled geophones in a parallel land streamer configuration. A sledge hammer with flat plate and spiked shear source was used for vertical, transverse, and inline source orientations. Left-right and front-back hits were used to generate the shear data. At each source location, five orientations of the source were used: vertical, transverse left-right, inline front-back. Thus the final data set consists of nine-component data. A spread consisted of 24 one meter spaced receiver locations. The source was moved through the stationary spread starting and ending two meters off the spread ends for 28 shots per spread. A total of three spreads were shot with spread move-up of one-half spread length. Data processing was done using a diving wave tomography approach and Rayfract software. The tomography approach uses first arrivals. First arrivals for the shear data were picked from differenced transverse shot gathers to remove compressional wave contamination. The transverse shear gathers were equalized before differencing. The resulting P-wave and S-wave velocity profiles were subsequently used to calculate a Poisson's ratio profile for the dam. The P-wave velocity profile shows zones of high velocity, approximately that of water, correlating with suspected zones of seepage. These zones occur at a depth of nine meters. Near the top of the P-wave profile, two low velocity anomalies and one higher velocity anomaly are apparent. No independent data exist to confirm the nature of these anomalies. The S-wave velocity profile does not exhibit the

  5. P- and S-wave seismic attenuation for deep natural gas exploration and development

    SciTech Connect

    Walls, Joel; Uden, Richard; Singleton, Scott; Shu, Rone; Mavko, Gary

    2005-04-12

    Using current methods, oil and gas in the subsurface cannot be reliably predicted from seismic data. This causes domestic oil and gas fields to go undiscovered and unexploited, thereby increasing the need to import energy.The general objective of this study was to demonstrate a simple and effective methodology for estimating reservoir properties (gas saturation in particular, but also including lithology, net to gross ratios, and porosity) from seismic attenuation and other attributes using P- and S-waves. Phase I specific technical objectives: Develop Empirical or Theoretical Rock Physics Relations for Qp and Qs; Create P-wave and S-wave Synthetic Seismic Modeling Algorithms with Q; and, Compute P-wave and S-wave Q Attributes from Multi-component Seismic Data. All objectives defined in the Phase I proposal were accomplished. During the course of this project, a new class of seismic analysis was developed based on compressional and shear wave inelastic rock properties (attenuation). This method provides a better link between seismic data and the presence of hydrocarbons. The technique employs both P and S-wave data to better discriminate between attenuation due to hydrocarbons versus energy loss due to other factors such as scattering and geometric spreading. It was demonstrated that P and S attenuation can be computed from well log data and used to generate synthetic seismograms. Rock physics models for P and S attenuation were tested on a well from the Gulf of Mexico. The P- and S-wave Q attributes were computed on multi-component 2D seismic data intersecting this well. These methods generated reasonable results, and most importantly, the Q attributes indicated gas saturation.

  6. S-wave velocity structure of the North China from inversion of Rayleigh wave phase velocity

    NASA Astrophysics Data System (ADS)

    Chen, Hao-peng; Zhu, Liang-bao; Wang, Qing-dong; Zhang, Pan; Yang, Ying-hang

    2014-07-01

    We constructed the S-wave velocity structure of the crust and uppermost mantle (10-100 km) beneath the North China based on the teleseismic data recorded by 187 portable broadband stations deployed in this region. The traditional two-step inversion scheme was adopted. Firstly, we measured the interstation fundamental Rayleigh wave phase velocity of 10-60 s and imaged the phase velocity distributions using the Tarantola inversion method. Secondly, we inverted the 1-D S-wave velocity structure with a grid spacing of 0.25° × 0.25° and constructed the 3-D S-wave velocity structure of the North China. The 3-D S-wave velocity model provides valuable information about the destruction mechanism and geodynamics of the North China Craton (NCC). The S-wave velocity structures in the northwestern and southwestern sides of the North-South Gravity Lineament (NSGL) are obviously different. The southeastern side is high velocity (high-V) while the northeastern side is low velocity (low-V) at the depth of 60-80 km. The upwelling asthenosphere above the stagnated Pacific plate may cause the destruction of the Eastern Block and form the NSGL. A prominent low-V anomaly exists around Datong from 50 to 100 km, which may due to the upwelling asthenosphere originating from the mantle transition zone beneath the Western Block. The upwelling asthenosphere beneath the Datong may also contribute to the destruction of the Eastern Block. The Zhangjiakou-Penglai fault zone (ZPFZ) may cut through the lithosphere and act as a channel of the upwelling asthenosphere. A noticeable low-V zone also exists in the lower crust and upper mantle lid (30-50 km) beneath the Beijing-Tianjin-Tangshan (BTT) region, which may be caused by the upwelling asthenosphere through the ZPFZ.

  7. Detailed p- and s-wave velocity models along the LARSE II transect, Southern California

    USGS Publications Warehouse

    Murphy, J.M.; Fuis, G.S.; Ryberg, T.; Lutter, W.J.; Catchings, R.D.; Goldman, M.R.

    2010-01-01

    Structural details of the crust determined from P-wave velocity models can be improved with S-wave velocity models, and S-wave velocities are needed for model-based predictions of strong ground motion in southern California. We picked P- and S-wave travel times for refracted phases from explosive-source shots of the Los Angeles Region Seismic Experiment, Phase II (LARSE II); we developed refraction velocity models from these picks using two different inversion algorithms. For each inversion technique, we calculated ratios of P- to S-wave velocities (VP/VS) where there is coincident P- and S-wave ray coverage.We compare the two VP inverse velocity models to each other and to results from forward modeling, and we compare the VS inverse models. The VS and VP/VS models differ in structural details from the VP models. In particular, dipping, tabular zones of low VS, or high VP/VS, appear to define two fault zones in the central Transverse Ranges that could be parts of a positive flower structure to the San Andreas fault. These two zones are marginally resolved, but their presence in two independent models lends them some credibility. A plot of VS versus VP differs from recently published plots that are based on direct laboratory or down-hole sonic measurements. The difference in plots is most prominent in the range of VP = 3 to 5 km=s (or VS ~ 1:25 to 2:9 km/s), where our refraction VS is lower by a few tenths of a kilometer per second from VS based on direct measurements. Our new VS - VP curve may be useful for modeling the lower limit of VS from a VP model in calculating strong motions from scenario earthquakes.

  8. P and S wave responses of bacterial biopolymer formation in unconsolidated porous media

    NASA Astrophysics Data System (ADS)

    Noh, Dong-Hwa; Ajo-Franklin, Jonathan B.; Kwon, Tae-Hyuk; Muhunthan, Balasingam

    2016-04-01

    This study investigated the P and S wave responses and permeability reduction during bacterial biopolymer formation in unconsolidated porous media. Column experiments with fine sands, where the model bacteria Leuconostoc mesenteroides were stimulated to produce insoluble biopolymer, were conducted while monitoring changes in permeability and P and S wave responses. The bacterial biopolymer reduced the permeability by more than 1 order of magnitude, occupying ~10% pore volume after 38 days of growth. This substantial reduction was attributed to the bacterial biopolymer with complex internal structures accumulated at pore throats. S wave velocity (VS) increased by more than ~50% during biopolymer accumulation; this indicated that the bacterial biopolymer caused a certain level of stiffening effect on shear modulus of the unconsolidated sediment matrix at low confining stress conditions. Whereas replacing pore water by insoluble biopolymer was observed to cause minimal changes in P wave velocity (VP) due to the low elastic moduli of insoluble biopolymer. The spectral ratio analyses revealed that the biopolymer formation caused a ~50-80% increase in P wave attenuation (1/QP) at the both ultrasonic and subultrasonic frequency ranges, at hundreds of kHz and tens of kHz, respectively, and a ~50-60% increase in S wave attenuation (1/QS) in the frequency band of several kHz. Our results reveal that in situ biopolymer formation and the resulting permeability reduction can be effectively monitored by using P and S wave attenuation in the ultrasonic and subultrasonic frequency ranges. This suggests that field monitoring using seismic logging techniques, including time-lapse dipole sonic logging, may be possible.

  9. J-matrix calculation of electron-helium S-wave scattering

    SciTech Connect

    Konovalov, D. A.; Fursa, D. V.; Bray, I.

    2011-09-15

    The J-matrix approach to electron-atom scattering is revised by merging it with the Fano's multiconfiguration interaction matrix elements [U. Fano, Phys. Rev. 140, A67 (1965)]. The revised method is then applied to the S-wave model of the e-He scattering problem demonstrating remarkable computational efficiency and accuracy. In particular, the method is in complete agreement with the convergent-close-coupling elastic, 2{sup 1,3}S excitation and single ionization cross sections for impact energies in the range 0.1-1000 eV. The S-wave resonance structures in the elastic and 2{sup 1,3}S excitation cross sections are highlighted.

  10. Effective p -wave interaction and topological superfluids in s -wave quantum gases

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Zheng, Zhen; Pu, Han; Zou, Xubo; Guo, Guangcan

    2016-03-01

    p -wave interaction in cold atoms may give rise to exotic topological superfluids. However, the realization of p -wave interaction in a cold atom system is experimentally challenging. Here we propose a simple scheme to synthesize effective p -wave interaction in conventional s -wave interacting quantum gases. The key idea is to load atoms into a spin-dependent optical lattice potential. Using two concrete examples involving spin-1/2 fermions, we show how the original system can be mapped into a model describing spinless fermions with nearest-neighbor p -wave interaction, whose ground state can be a topological superfluid that supports Majorana fermions under proper conditions. Our proposal has the advantage that it does not require spin-orbit coupling or loading atoms onto higher orbitals, which is the key in earlier proposals to synthesize effective p -wave interaction in s -wave quantum gases, and may provide a completely new route for realizing p -wave topological superfluids.

  11. Three-dimensional P and S wave velocity structures of southern Peru and their tectonic implications

    NASA Technical Reports Server (NTRS)

    Cunningham, Paul S.; Roecker, Steven W.; Hatzfeld, Denis

    1986-01-01

    Arrival times of compressional and shear (S) waves from microearthquakes recorded in 1981 by an 18-station regional array are used to study the three-dimensional velocity structure of the crust and upper mantle of the central Andes. The data suggest a crustal thickness of about 40 km beneath the coast, increasing to about 70 km beneath the Cordillera Occidental. The inverse correlation between the dip in the Moho and the dip of the slab may indicate a broad-scale causal relation between the two. S wave velocities in the mantle between 70 and 130 km depth above the 30-degree dipping slab are low, possibly indicating the presence of a partially melted asthenosphere that may be responsible for the magmatic activity recorded in southern Peru.

  12. S-wave envelope broadening characteristics of microearthquakes in the Canary Islands

    NASA Astrophysics Data System (ADS)

    Ugalde, Arantza

    2013-04-01

    This study analyzes the S-wave envelope broadening characteristics of 290 earthquakes recorded by 14 stations of the Spanish National Seismograph Network in the Canary Islands region. The S-wave peak delay time ( t p ) and envelope duration ( t q ) parameters are evaluated phenomenologically to infer the strength of velocity inhomogeneities of the medium along each seismic ray path. Crustal (0 ≤ h ≤ 18 km) and upper mantle (18 < h ≤ 80 km) events are analyzed separately. Results in the frequency range 1 to 12 Hz for hypocentral distances from 30 to 600 km show that both t p and t q increase according to a power of hypocentral distance and they are independent of frequency. The spatial distribution of the peak delay time reveals weak strength of heterogeneity in most of the region at shallow depths. Relatively strong inhomogeneous zones are generated under the island of Tenerife and Gran Canaria at depths of 11-22 km.

  13. Possibility of an s-wave pion condensate in neutron stars reexamined

    SciTech Connect

    Ohnishi, A.; Jido, D.; Sekihara, T.; Tsubakihara, K.

    2009-09-15

    We examine possibilities of pion condensation with zero momentum (s-wave condensation) in neutron stars by using the pion-nucleus optical potential U and the relativistic mean field (RMF) models. We use low-density phenomenological optical potentials parametrized to fit deeply bound pionic atoms or pion-nucleus elastic scatterings. The proton fraction (Y{sub p}) and electron chemical potential ({mu}{sub e}) in neutron star matter are evaluated in RMF models. We find that the s-wave pion condensation hardly takes place in neutron stars and especially has no chance if hyperons appear in neutron star matter and/or the b{sub 1} parameter in U has density dependence.

  14. Temporal Changes in S-Wave Velocity at Different Depths Near Parkfield, CA

    NASA Astrophysics Data System (ADS)

    Wu, C.; Delorey, A. A.; Brenguier, F.; Guyer, R. A.; Gomberg, J. S.; Johnson, P. A.

    2014-12-01

    The 2003 Mw6.5 San Simeon earthquake and the 2004 Mw6.0 Parkfield earthquake have been found to cause significant seismic velocity decreases along the San Andreas Fault (SAF). However, the depth range of the velocity decreases is hard to constrain based on traditional approaches and is still inclusive. In this study, we used noise interferometry (MSNoise) and surface wave inversion to measure the S-wave velocity changes at different depths near Parkfield after the two large earthquakes. We processed continuous seismic recordings from 15 stations near Parkfield from 2001 to 2011 to obtain the noise cross-correlation functions, and measured the temporal variations in Rayleigh wave phase velocities at 6 different frequency bands. We then invert the Rayleigh wave phase velocity changes at different frequencies using a series of Rayleigh wave sensitivity kernels, for the S-wave velocity changes at different depths. Our results indicate that the S-wave velocity decreases caused by the San Simeon earthquake are relatively small (up to ~0.1%), and they access depths of at least 6 km in the region of Parkfield. On the other hand, the S-wave velocity decrease caused by the Parkfield earthquake is larger (up to ~0.3%), but is dominated by elastic changes in the top 1-2 km of the crust. Our ongoing work is focused on constraining and understanding the physical mechanisms for the different depth ranges of velocity changes cause by the two large earthquakes, and characterization of the recovery processes at different depths after the Parkfield earthquake.

  15. S -wave nonleptonic hyperon decays and Ξb-→π-Λb

    NASA Astrophysics Data System (ADS)

    Gronau, Michael; Rosner, Jonathan L.

    2016-02-01

    The decay Ξb-→π-Λb has recently been observed by the LHCb Collaboration at CERN. In contrast to most weak decays of b -flavored baryons, this process involves the decay of the strange quark in Ξb and thus has features in common with nonleptonic weak decays of hyperons. Thanks to the expected pure S-wave nature of the decay in question in the heavy b quark limit, we find that its amplitude may be related to those for S-wave nonleptonic decays of Λ , Σ , and Ξ in a picture inspired by duality. The calculated branching fraction B (Ξb-→π-Λb)=(6.3 ±4.2 )×10-3 is consistent with the range allowed in the LHCb analysis. The error is dominated by an assumed 30% uncertainty in the amplitude due to possible U(3) violation. A more optimistic view based on sum rules involving nonleptonic hyperon decay S-wave amplitudes reduces the error on the branching fraction to 2.0 ×10-3.

  16. ESTIMATION OF S-WAVE VELOCITY STRUCTURE OF FUKUI PLAIN BASED ON MICROTREMOR ARRAY OBSERVATION

    NASA Astrophysics Data System (ADS)

    Kojima, Keisuke; Moto, Koudai

    The precise evaluations of Quaternary structure of the region are indispensable in order to accurately predict the seismic damage. However, deep borehole, PS-logging and elastic wave exploration have been executed only on limited points around the Fukui Plain. The problem analyzed in this study is statistical estimation of the 3D S-wave velocity structure down to the Tertiary bedrock of the Fukui Plain based on the data from 75 microtremor array observation sites. The Rayleigh wave phase velocities at each array site were calculated by the spatial autocorrelation method. The phase velocities at each site were inverted to a 1D S-wave profile using a genetic inversion. The 3-components single-site microtremor observations were carried out to compensate the array observations. The 3D S-wave velocity structure around the Fukui plain have been interpolated by using Kriging and Co-Kriging techniques. In the Co-Kriging procedure, the correlations between the estimated depths of Quaternary and the observed predominant periods of the sites were taken into account. The validity of the estimated structure from the microtremor observation was confirmed by comparing with the density structure and with the existing PS-logging data.

  17. Developing Strength Chart of Saturated Concrete by Using Seismic P and S-Wave Velocities in Laboratory

    NASA Astrophysics Data System (ADS)

    Ekinci, B.; Sabbağ, N.; Uyanik, O.; Öncü, Z.; Akdemir, S.; Türker, E.

    2014-12-01

    Determining of concrete strength can be used by destructive or non-destructive methods. Concrete strength is determined with uniaxial compressive test as destructive in laboratory and with Seismic Ultrasonic P- (Compressional) and S-wave (Shear) measurements as non-destructive in-situ or laboratory. In this study, strength of saturated concrete is investigated by using seismic P and S-wave velocities. For this, concrete samples were formed with using the cube samples in size 15x15x15cm. Different strength designs were made for obtain different strengths in these samples. The aim is to create concrete strengths of between the lowest 5MPa and the highest 100 MPa. After the end of the curing time of created the cube concrete samples Seismic P and S waves measurements were made in the laboratory by Ultrasonic test equipment. Hence, P and S wave velocities of the sample were calculated. After these, for determine the strength of the samples uniaxial compression strength test was performed. As a result, P and S wave velocities and concrete strength values of concrete samples were obtained. By correlating these values over %90 exponential relationships were determined. By using this relationship, concrete strength can be determined sensitively from P and S wave velocities. In addition, by using P and S wave velocities elastic parameters values and Poisson's ratio of concrete specimens can be calculated. Keywords: Concrete, Strength, Compressional and Shear-wave velocities, Empirical Relationship

  18. Mantle deformation patterns beneath southern Tibet using splitting of direct-S waves

    NASA Astrophysics Data System (ADS)

    Mohanty, Debasis D.; Eken, Tuna; Singh, Arun; Singh, Chandrani; Kumar, M. Ravi

    2016-04-01

    This study presents a total of 12008 shear wave splitting measurements obtained using the reference station technique applied to direct S-waves from 106 earthquakes recorded at 143 seismic stations of the Hi-CLIMB seismic network. The results reveal significant anisotropy in regions of southern Tibet where null or negligible anisotropy has been hitherto reported from SK(K)S measurements. While the individual fast polarization direction (FPD) at each station are found to be consistent, the splitting time delays (TDs) exhibit deviations particularly at stations located south of the Indus-Tsangpo Suture Zone. The fast polarization directions (FPDs) are oriented (a) NE-SW to E-W to the south of the Indus-Tsangpo Suture Zone (b) NE-SW to ENE-SSW between Bangong-Nujiang Suture Zone and the Indus-Tsangpo Suture Zone (ITSZ) and (c) E-W to the extreme north of the profile. The splitting time delays (dt) vary between 0.45 and 1.3 s south of the ITSZ (<30 N latitude), while they range from 0.9 to 1.4 s north of it. The overall trends are similar to SKS/SKKS results. However, the differences may be due to the not so near vertical paths of direct S waves which may sample the anisotropy in a different way in comparison to SKS waves, or insufficient number of SKS observations. The significant anisotropy ( 0.8 s) observed beneath Himalaya reveals a complex deformation pattern in the region and can be best explained by the combined effects of deformation related to shear at the base of the lithosphere and subduction related flows with possible contributions from the crust. Additional measurements obtained using direct S-waves provide new constraints in regions with complex anisotropy.

  19. Significant seismic anisotropy beneath southern Tibet inferred from splitting of direct S-waves

    NASA Astrophysics Data System (ADS)

    Singh, Arun; Eken, Tuna; Mohanty, Debasis D.; Saikia, Dipankar; Singh, Chandrani; Ravi Kumar, M.

    2016-01-01

    This study presents a total of 12008 shear wave splitting measurements obtained using the reference-station technique applied to direct S-waves from 106 earthquakes recorded at 143 seismic stations of the Hi-CLIMB seismic network. The results reveal significant anisotropy in regions of southern Tibet where null or negligible anisotropy has been hitherto reported from SK(K)S measurements. While the individual fast polarization direction (FPD) at each station are found to be consistent, the splitting time delays (TDs) exhibit deviations particularly at stations located south of the Indus-Tsangpo Suture Zone. The fast polarization directions (FPDs) are oriented (a) NE-SW to E-W to the south of the Indus-Tsangpo Suture Zone (b) NE-SW to ENE-SSW between Bangong-Nujiang Suture Zone and the Indus-Tsangpo Suture Zone (ITSZ) and (c) E-W to the extreme north of the profile. The splitting time delays (δt) vary between 0.45 and 1.3 s south of the ITSZ (<30°N latitude), while they range from 0.9 to 1.4 s north of it. The overall trends are similar to SKS/SKKS results. However, the differences may be due to the not so near vertical paths of direct S waves which may sample the anisotropy in a different way in comparison to SKS waves, or insufficient number of SKS observations. The significant anisotropy (∼ 0.8 s) observed beneath Himalaya reveals a complex deformation pattern in the region and can be best explained by the combined effects of deformation related to shear at the base of the lithosphere and subduction related flows with possible contributions from the crust. Additional measurements obtained using direct S-waves provide new constraints in regions with complex anisotropy.

  20. Global S-wave tomography using receiver pairs: an alternative to get rid of earthquake mislocation

    NASA Astrophysics Data System (ADS)

    Zaroli, C.; Lévêque, J.-J.; Schuberth, B. S. A.; Duputel, Z.; Nolet, G.

    2014-11-01

    Global seismic tomography suffers from uncertainties in earthquake parameters routinely published in seismic catalogues. In particular, errors in earthquake location and origin-time may lead to strong biases in measured body wave delay-times and significantly pollute tomographic models. Common ways of dealing with this issue are to incorporate source parameters as additional unknowns into the linear tomographic equations, or to seek combinations of data to minimize the influence of source mislocations. We propose an alternative, physically-based method to desensitize direct S-wave delay-times to errors in earthquake location and origin-time. Our approach takes advantage of the fact that mislocation delay-time biases depend to first order on the earthquake-receiver azimuth, and to second order on the epicentral distance. Therefore, for every earthquake, we compute S-wave differential delay-times between optimized receiver pairs, such that a large part of their mislocation delay-time biases cancels out (for example origin-time fully subtracts out), while the difference of their sensitivity kernels remains sensitive to the model parameters of interest. Considering realistic, randomly distributed source mislocation vectors, as well as various levels of data noise and different synthetic Earths, we demonstrate that mislocation-related model errors are highly reduced when inverting for such differential delay-times, compared to absolute ones. The reduction is particularly rewarding for imaging the upper-mantle and transition zone. We conclude that using optimized receiver pairs is a suitable, low cost alternative to get rid of errors on earthquake location and origin-time for teleseismic direct S-wave traveltimes. Moreover, it can partly remove unilateral rupture propagation effects in cross-correlation delay-times, since they are similar to mislocation effects.

  1. Global S-Wave Tomography Using Receiver Pairs: An Alternative to Get Rid of Earthquake Mislocation

    NASA Astrophysics Data System (ADS)

    Leveque, J. J.; Zaroli, C.; Schuberth, B. S. A.; Duputel, Z.; Nolet, G.

    2014-12-01

    Global seismic tomography suffers from uncertainties in earthquake parameters routinely published in seismic catalogues. In particular, errors in earthquake location and origin-time may lead to strong biases in measured body-wave delay-times and significantly pollute tomographic models. Common ways of dealing with this issue are to incorporate source parameters as additional unknowns into the linear tomographic equations, or to seek combinations of data to minimise the influence of source mislocations.We propose an alternative, physically-based method to desensitise direct S-wave delay-times to errors in earthquake location and origin-time. Our approach takes advantage of the fact that mislocation delay-time biases depend to first order on the earthquake-receiver azimuth, and to second order on the epicentral distance. Therefore, for every earthquake, we compute S-wave differential delay-times between optimised receiver pairs, such that a large part of their mislocation delay-time biases cancels out (for example origin-time fully subtracts out), while the difference of their sensitivity kernels remains sensitive to the model parameters of interest. Considering realistic, randomly distributed source mislocation vectors, as well as various levels of data noise and different synthetic Earths, we demonstrate that mislocation-related model errors are highly reduced when inverting for such differential delay-times, compared to absolute ones. The reduction is particularly rewarding for imaging the upper-mantle and transition-zone.We conclude that using optimised receiver pairs is a suitable, low cost alternative to get rid of errors on earthquake location and origin-time for teleseismic direct S-wave traveltimes. Moreover, it can partly remove unilateral rupture propagation effects in cross-correlation delay-times, since they are similar to mislocation effects.

  2. Characterization of S-waves Generated from Aboveground and Underground Explosions in Alluvium

    NASA Astrophysics Data System (ADS)

    Bonner, J. L.; Napoli, V.; Reinke, R.

    2014-12-01

    The source of S-waves from explosions is debated within the nuclear explosion monitoring community. The HUMBLE REDWOOD III (HRIII) experiment series in 2012 located in New Mexico provides a unique dataset to further our understanding of the generation of S-waves in alluvium by comparing and contrasting co-located aboveground and underground explosions. Two 91 kg explosions were detonated in alluvium at the same location, but HRIII-1 was detonated at 2 m aboveground and HRIII-2 was detonated at 7 m belowground and was fully coupled. A semicircular seismic network of 21 stations was deployed at 1 km to record the explosions. We determined that the belowground HRIII-2 explosion generated P-waves that were 2.4x larger than the aboveground HRIII-1 shot, thus we scaled the aboveground signals by this factor. Visual inspection of the waveforms after scaling showed similar P-wave, higher mode (HM) Rayleigh-wave, and fundamental mode Rayleigh-wave amplitudes for both shots on the vertical and radial components; however the largest differences were observed on the transverse components. Additional Love wave (or SH) energy is generated by the underground explosion that is not accounted for in the P-wave scaling factor. Spectral ratios confirm that the increased SH generation occurs at frequencies between 10-100 Hz. Future work includes modeling of these waveforms to explain the larger SH waves as well as analysis of S-wave generation from a similar set of above- and below-ground explosions in limestone.

  3. P- and S-wave velocity measurements on saturated siliceous conglomerates: determination of frame moduli

    NASA Astrophysics Data System (ADS)

    He, T.; Schmitt, D. R.

    2005-12-01

    Reservoir conditions, such as the pore pressure and the fluid saturation levels, will change during the production of fluids from the earth. These changes will also influence the seismic wave properties of the rock. In order to better understand its seismic response, compressional and shear wave velocities were measured on a series of low porosity (less than 10%) conglomerates under different confining and pore pressures under both dry and water saturated conditions. P- and S-wave velocities were simultaneously measured using standard pulse transmission methods. In all cases, the velocities increased dramatically with effective confining pressures to 60 MPa. As expected, saturated P-wave velocities were always greater than those under `dry' (i.e. pore space under vacuum) conditions. Conventional assumptions leading from Gassmann's relations suggest that the S-wave velocity would drop; however, in this study the S-wave velocity increased after saturation. The contradiction of the observed data with the theory has been attributed to a number of mechanisms, such as viscous coupling, the reduction in free surface energy, and frequency dispersion due to local flow of the fluid in the microcracks. The pore geometry, the microcracks and the clay content are among the most important factors influencing the seismic properties of these rocks. These geological factors are characterized though thin section, Scanning Electron Microscope (SEM), and Hg-porosimetry. The stress sensitive intra- and inter-grain cracks observed through these images play an important role in the velocity pressure relationship. The variation of the Vp/Vs and Poisson's ratios as functions of the effective pressure are also shown.

  4. Experimental Evidence of s-Wave Superconductivity in Bulk CaC6

    NASA Astrophysics Data System (ADS)

    Lamura, G.; Aurino, M.; Cifariello, G.; di Gennaro, E.; Andreone, A.; Emery, N.; Hérold, C.; Marêché, J.-F.; Lagrange, P.

    2006-03-01

    The temperature dependence of the in-plane magnetic penetration depth, λab(T), has been measured in a c-axis oriented polycrystalline CaC6 bulk sample using a high-resolution mutual inductance technique. A clear exponential behavior of λab(T) has been observed at low temperatures, strongly suggesting isotropic s-wave pairing. Data fit using the standard BCS theory yields λab(0)=(720±80)Å and Δ(0)=(1.79±0.08)meV. The ratio 2Δ(0)/kBTc=(3.6±0.2) gives indication for a weakly coupled superconductor.

  5. S-wave K- pi+ system in D+ ---> K- pi+ pi+ decays from Fermilab E791

    SciTech Connect

    Meadows, B.T.; /Cincinnati U.

    2005-06-01

    A new approach to the analysis of three body decays is presented. Model-independent results are obtained for the S-wave K{pi} amplitude as a function of K{pi} invariant mass. These are compared with results from K{sup -}{pi}{sup +} elastic scattering, and the prediction of the Watson theorem, that the phase behavior be the same below K{eta}' threshold, is tested. Contributions from I = 1/2 and I = 3/2 are not resolved in this study. If I = 1/2 dominates, however, the Watson theorem does not describe these data well.

  6. 3D P and S Wave Velocity Structure and Tremor Locations in the Parkfield Region

    NASA Astrophysics Data System (ADS)

    Zeng, X.; Thurber, C. H.; Shelly, D. R.; Bennington, N. L.; Cochran, E. S.; Harrington, R. M.

    2014-12-01

    We have assembled a new dataset to refine the 3D seismic velocity model in the Parkfield region. The S arrivals from 184 earthquakes recorded by the Parkfield Experiment to Record MIcroseismicity and Tremor array (PERMIT) during 2010-2011 were picked by a new S wave picker, which is based on machine learning. 74 blasts have been assigned to four quarries, whose locations were identified with Google Earth. About 1000 P and S wave arrivals from these blasts at permanent seismic network were also incorporated. Low frequency earthquakes (LFEs) occurring within non-volcanic tremor (NVT) are valuable for improving the precision of NVT location and the seismic velocity model at greater depths. Based on previous work (Shelley and Hardebeck, 2010), waveforms of hundreds of LFEs in same family were stacked to improve signal qualify. In a previous study (McClement et al., 2013), stacked traces of more than 30 LFE families at the Parkfileld Array Seismic Observatory (PASO) have been picked. We expanded our work to include LFEs recorded by the PERMIT array. The time-frequency Phase Weight Stacking (tf-PWS) method was introduced to improve the stack quality, as direct stacking does not produce clear S-wave arrivals on the PERMIT stations. This technique uses the coherence of the instantaneous phase among the stacked signals to enhance the signal-to-noise ratio (SNR) of the stack. We found that it is extremely effective for picking LFE arrivals (Thurber et al., 2014). More than 500 P and about 1000 S arrivals from 58 LFE families were picked at the PERMIT and PASO arrays. Since the depths of LFEs are much deeper than earthquakes, we are able to extend model resolution to lower crustal depths. Both P and S wave velocity structure have been obtained with the tomoDD method. The result suggests that there is a low velocity zone (LVZ) in the lower crust and the location of the LVZ is consistent with the high conductivity zone beneath the southern segment of the Rinconada fault that

  7. Anisotropic transport properties in a layered d+s-wave superconductor

    SciTech Connect

    Nicol, E.J.; Kim, Heesang; Palumbo, M.; Graf, M.J.

    1996-11-01

    Recent measurements of the penetration depth and optical conductivity in YBa{sub 2}Cu{sub 3}O{sub x} (YBCO) single crystals suggest the possibility of an order parameter with d+s-wave symmetry. The authors present results from calculations of both the anisotropic low temperature penetration depth and the frequency-dependent conductivity for a layered superconductor with such a pairing symmetry. The system is modelled as a stack of weakly coupled, two dimensional superconducting planes, and the effect of non-magnetic impurity scattering in both Born and unitarity limits is examined.

  8. Constraining the Lithospheric Structure of the Central Andes Using P- and S- wave Receiver Functions

    NASA Astrophysics Data System (ADS)

    Ryan, J. C.; Beck, S. L.; Zandt, G.; Wagner, L. S.; Minaya, E.; Tavera, H.

    2014-12-01

    The Central Andean Plateau (CAP) has elevations in excess of 3 km, and is part of the Andean Cordillera that resulted in part from shortening along the western edge of South America as it was compressed between the subducting Nazca plate and underthrusting Brazilian cratonic lithosphere. We calculated P- and S-wave receiver functions for the Central Andean Uplift and Geodynamics of High Topography (CAUGHT) temporary deployment of broadband seismometers in the Bolivian orocline (12°-20°S) region to investigate crustal thickness and lithospheric structure. Migration of the receiver functions is done using common conversion point (CCP) stacks through a 3D shear velocity model from ambient noise tomography (Ward et al., 2013). The P- and S-wave receiver functions provide similar estimates of the depth to Moho under the CAP. Crustal thicknesses include 60-65 km thick crust underneath the Bolivian Altiplano, crust that varies from ~70 km to ~50 km underneath the Eastern Cordillera and Interandean zone, and thins to 50 to 40 km crust in the Subandes and the edge of the foreland. The variable crustal thickness of the Eastern Cordillera and Interandean zone ranges from >70 km associated with the Los Frailes volcanic field at 19°-20°S to ~55 km beneath the 6 km peaks of the Cordillera Real at ~16°S. From our S-wave receiver functions, that have no multiples that can interfere with deeper structure, we also identify structures below the Moho. Along a SW-NE line that runs near La Paz where we have our highest station density, the S-wave CCP receiver-function stacks show a strong negative polarity arrival at a depth of ~120 km from the eastern edge of the Altiplano to the Subandean zone. We suggest this may be a good candidate for the base of the CAP lithosphere. In addition, above this depth the mantle is strongly layered, suggesting that there is not a simple high velocity mantle lithosphere associated with the continental lithosphere underthrusting the Andean orogen

  9. Charge independence, charge symmetry breaking in the S-wave nucleon-nucleon interaction, and renormalization

    SciTech Connect

    Alvaro Calle Cordon,Manuel Pavon Valderrama,Enrique Ruiz Arriola

    2012-02-01

    We study the interplay between charge symmetry breaking and renormalization in the NN system for S-waves. We find a set of universality relations which disentangle explicitly the known long distance dynamics from low energy parameters and extend them to the Coulomb case. We analyze within such an approach the One-Boson-Exchange potential and the theoretical conditions which allow to relate the proton-neutron, proton-proton and neutron-neutron scattering observables without the introduction of extra new parameters and providing good phenomenological success.

  10. Charge symmetry breaking effect for 3H and 3He within s-wave approach

    NASA Astrophysics Data System (ADS)

    Filikhin, I.; Suslov, V. M.; Vlahovic, B.

    2016-06-01

    Three-nucleon systems are considered assuming the neutrons and protons to be distinguishable particles. The configuration space Faddeev equations are exploited to calculate ground state energies of 3H and 3He nuclei within an s-wave approach applying the Malfliet-Tjon, Tamagaki G3RS and Afnan-Tang ATS3 NN potentials. We modify the potentials by scaling strength parameters to define nn, pp and np singlet components. The scaling parameters are fixed to reproduce experimental scattering lengths. The charge symmetry breaking energy is numerically evaluated. The relation between nn, pp and np singlet potentials is discussed.

  11. Gas hydrate concentration estimated from P- and S-wave velocities

    NASA Astrophysics Data System (ADS)

    Carcione, J. M.; Gei, D.

    2003-04-01

    We estimate the concentration of gas hydrate at the Mallik 2L-38 research site, Mackenzie Delta, Canada, using P- and S-wave velocities obtained from well logging and vertical seismic profiles (VSP). The theoretical velocities are obtained from a poro-viscoelastic model based on a Biot-type approach. It considers the existence of two solids (grains and gas hydrate) and a fluid mixture and is based on the assumption that hydrate fills the pore space and shows interconnection. The moduli of the matrix formed by gas hydrate are obtained from the percolation model described by Leclaire et al., (1994). An empirical mixing law introduced by Brie et al., (1995) provides the effective bulk modulus of the fluid phase, giving Wood's modulus at low frequency and Voigt's modulus at high frequencies. The dry-rock moduli are estimated from the VSP profile where the rock is assumed to be fully saturated with water, and the quality factors are obtained from the velocity dispersion observed between the sonic and VSP velocities. Attenuation is described by using a constant-Q model for the dry rock moduli. The amount of dissipation is estimated from the difference between the seismic velocities and the sonic-log velocities. We estimate the amount of gas hydrate by fitting the sonic-log and seismic velocities to the theoretical velocities, using the concentration of gas hydrate as fitting parameter. We obtain hydrate concentrations up to 75 %, average values of 43 and 47 % from the VSP P- and S-wave velocities, respectively, and 47 and 42 % from the sonic-log P- and S-wave velocities, respectively. These averages are computed from 897 to 1110 m, excluding the zones where there is no gas hydrate. We found that modeling attenuation is important to obtain reliable results. largeReferences} begin{description} Brie, A., Pampuri, F., Marsala A.F., Meazza O., 1995, Shear Sonic Interpretation in Gas-Bearing Sands, SPE Annual Technical Conference and Exhibition, Dallas, 1995. Carcione, J

  12. Three-dimensional distribution of S wave reflectors in the northern Kinki district, southwestern Japan

    NASA Astrophysics Data System (ADS)

    Aoki, Sho; Iio, Yoshihisa; Katao, Hiroshi; Miura, Tsutomu; Yoneda, Itaru; Sawada, Masayo

    2016-06-01

    Distinct reflected waves (S × S) are observed in the northern Kinki district, southwestern Japan. We conducted a high-resolution reflection analysis by using data from 128 seismic stations with an average spacing of about 5 km. We used a stacking method to obtain three-dimensional distributions of relative reflection strengths of S waves and found a thin planar zone of high reflection strengths at depths of 25-30 km, which we call a S wave reflector. We also found that the zone of high reflection strengths is dipping to the north and that low-frequency earthquakes (LFEs) occurred near the edge of the zone at depths around the Moho discontinuity. It is inferred from these results that fluid is concentrated in this zone of high reflection strengths. It is likely that the zone of high reflection strengths is a path of fluid upwelling from the mantle, together with the hypocentral region of LFEs, that is located near the lower edge of the zone. The northern Kinki district is thought to be part of the Niigata-Kobe Tectonic Zone (NKTZ) high strain rates region. The high reflection strengths zone may be associated with high strain rates in the NKTZ.

  13. Synthetic p-wave interaction and topological superfluids in s-wave quantum gases

    NASA Astrophysics Data System (ADS)

    Pu, Han; Wang, Bin; Zheng, Zhen; Zou, Xubo; Guo, Guangcan

    2016-05-01

    P-wave interaction in cold atoms may give rise to exotic topological superfluids. However, realization of p-wave interaction in cold atom system is experimentally challenging. Here we propose a simple scheme to synthesize effective p-wave interaction in conventional s-wave interacting quantum gases. The key idea is to load atoms into spin-dependent optical lattice potential. Using two concrete examples involving spin-1/2 fermions, we show how the original system can be mapped into a model describing spinless fermions with nearest neighbor p-wave interaction, whose ground state can be a topological superfluid that supports Majorana fermions under proper conditions. Our proposal has the advantage that it does not require spin-orbit coupling or loading atoms onto higher orbitals, which is the key in earlier proposals to synthesize effective p-wave interaction in s-wave quantum gases, and may provide a completely new route for realizing p-wave topological superfluids.

  14. Chiral Restoration in a Nuclear Medium ---Probed by S-Wave Pion Dynamics---

    NASA Astrophysics Data System (ADS)

    Kienle, P.

    Using 500 MeV (d,^3He π^-) pion transfer reactions in recoil free kinematics, pionic 1s-states were populated in the ^{115,119,123}Sn isotopes and their binding energies and widths determined by precision missing mass spectroscopy. Using these data and corresponding ones from iso-scalar light nuclei nuclei, ^{16}O, ^{20}Ne and ^{28}Si, we determined the pion nucleus s-wave strength parameters, b_0, b_1, Re B_0, and Im B_0. By comparison of the iso-vector pion nucleon strength, determined from pionic hydrogen X-ray spectroscopy b_1^{free}, with the b_1 in a nuclear medium scaled to the density ρ(0), we deduced a scaling factor, the square of the pion decay constant in the vacuum and in nuclear medium, as R = b_1^{free} / b_1 = f^2_{π}(ρ_0)/f^2_{π} = 0.64. Thus from the observed increase of the pion s-wave iso-vector strength in a nuclear medium a reduction of f^2_{π}, the order parameter of chiral symme try breaking, is indicated in accordance with theoretical expectations. This finding is supported by recent π^+ and π^- scattering experiments. A short outlook is given on a future program at RIBF in RIKEN for precision studies of deeply bound 1s-states in heavy nuclei.

  15. Tomographic Imaging of Upper Mantle P- and S-wave Velocity Heterogeneity Beneath the Arabian Peninsula

    SciTech Connect

    Park, Y; Nyblade, A; Rodgers, A; Al-Amri, A

    2005-08-30

    We report the estimates of three-dimensional P- and S-wave velocity structure beneath the Arabian Peninsula estimated from travel time delay tomography. We have completed travel time measurements and inversion of a partial data set provided by King Abdulaziz City for Science and Technology (KACST). This study builds on previous work by Benoit et al. (2003) following the methods of VanDecar and Crosson (1990) and VanDecar (1991). Data were collected from the Saudi Arabian National Digital Seismic Network (SANDSN) operated by KACST. The network consists of 38 stations (27 broadband and 11 short-period). We augmented the KACST data with delay times measured from permanent Incorporated Research Institutions for Seismology (IRIS) stations in the region (RAYN, EIL and MRNI) and the 1996 Saudi Arabian PASSCAL Experiment. This study shows the inverted P- and S-wave models computed with the combined data with all three different seismic networks (KASCST, IRIS, and the 1996 Saudi Arabian PASSCAL experiment) with best coverage beneath the Arabian Shield. Tomographic images reveal low velocity features in the upper mantle along a north-south line from the southern Asir region to the northeastern portion of the Arabian Shield.

  16. S-wave identification by polarization filtering and waveform coherence analysis

    NASA Astrophysics Data System (ADS)

    Amoroso, O.; Maercklin, N.; Zollo, A.

    2011-04-01

    The increasing number of seismic networks with high density of stations offers an ever larger amount of three-component recordings of earthquakes in a wide range of magnitudes. The analysis of these data can provide detailed information on both the propagation medium and the seismic source. In particular, the S-wave velocity is a key parameter for the understanding of the compositional and physical state of the lithosphere. On the other hand this requires a tool for identifying the seismic phase. The S-phase can be identified by a change in amplitude and frequency content of the signal with respect to the P-phase. The precise identification of S-phase is generally made difficult by the interference of P-coda waves, the arrival of converted phases generated beneath the recording site or the S-wave splitting. These factors can lead the operator to misidentify the phase or, very often, to abandon reading itself. In this study, we propose a data processing technique aimed at univocally identifying the arrival-time of the S-phase by using three component recordings available at all stations of a seismic network. The proposed technique provides an additional support to the operators to be used for both the analysis of a single event or for the massive, quasi-automatic analysis of huge datasets. The technique is based on the combination of a polarization detector mainly used in passive seismology and the move-out and stack analysis of trace gathers as for the velocity analysis in exploration seismics. The processing consists of four main steps. The first consists in P-phase picking and event location. The second step is the setting-up polarization detector: we rotate the three-component seismograms into the ray-coordinate system (L,Q,T), using theoretical backazimuths and incidence angles from P-phase polarizations. In the new system we calculate the directivity D, which is defined as the normalized angle between the P-phase polarization L and the actual polarization

  17. Three-dimensional P- and S-wave velocity structure along the central Alpine Fault, South Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Guo, B.; Thurber, C. H.; Roecker, S. W.; Townend, J.; Rawles, C.; Chamberlain, C. J.; Boese, C. M.; Bannister, S. C.

    2014-12-01

    The Deep Fault Drilling Project (DFDP) on the central Alpine Fault, South Island, New Zealand, has motivated a broad range of geophysical and geological studies aiming to characterize the fault system in the locality of the drill site at various scales. We have been developing three-dimensional P- and S-wave velocity models of the region by double-difference tomography utilizing datasets from multiple seismic networks (WIZARD, SAMBA, ALFA, GeoNet, and others). In our previous work, the quality of the S-wave model has been poor due to the small number of available S-wave picks. We have utilized a new high-accuracy automatic S-wave picker to increase the number of usable S arrivals by an order of magnitude, thereby dramatically improving the S-wave velocity model. Compared to previous studies, e.g. Eberhart-Phillips and Bannister (2002) and Feenstra et al (2013), our updated P-wave model shows a clear high Vp body (Vp > 6km/s) at depths of 5-15 km near the drill site. With our better resolved S-wave velocity model, we can see a sharp high Vs body (Vs > 3.7 km/s) in the same region. The newly added S-picks help to improve the accuracy of the relocations of the earthquakes . This in turn has highlighted the presence of earthquake swarms within the low velocity zone. Together with the updated earthquake relocations, the P- and S-wave tomography results reveal the Alpine Fault to be marked by a velocity contrast throughout most of the study region. The fault dips steeply from 5 to 20 km depth with an average dip of 50-60° SE, as inferred from the velocity structure and the seismicity.

  18. Attenuation of High Frequency P and S Waves in the Gujarat Region, India

    NASA Astrophysics Data System (ADS)

    Chopra, Sumer; Kumar, Dinesh; Rastogi, B. K.

    2011-05-01

    The local earthquake waveforms recorded on broadband seismograph network of Institute of Seismological Research in Gujarat, India have been analyzed to understand the attenuation of high frequency (2-25 Hz) P and S waves in the region. The frequency dependent relationships for quality factors for P ( Q P) and S ( Q S) waves have been obtained using the spectral ratio method for three regions namely, Kachchh, Saurashtra and Mainland Gujarat. The earthquakes recorded at nine stations of Kachchh, five stations of Saurashtra and one station in mainland Gujarat have been used for this analysis. The estimated relations for average Q P and Q S are: Q P = (105 ± 2) f 0.82 ± 0.01, Q S = (74 ± 2) f 1.06 ± 0.01 for Kachchh region; Q P = (148 ± 2) f 0.92 ± 0.01, Q S = (149 ± 14) f 1.43 ± 0.05 for Saurashtra region and Q P = (163 ± 7) f 0.77 ± 0.03, Q S = (118 ± 34) f 0.65 ± 0.14 for mainland Gujarat region. The low Q (<200) and high exponent of f (>0.5) as obtained from present analysis indicate the predominant seismic activities in the region. The lowest Q values obtained for the Kachchh region implies that the area is relatively more attenuative and heterogeneous than other two regions. A comparison between Q S estimated in this study and coda Q ( Qc) previously reported by others for Kachchh region shows that Q C > Q S for the frequency range of interest showing the enrichment of coda waves and the importance of scattering attenuation to the attenuation of S waves in the Kachchh region infested with faults and fractures. The Q S/ Q P ratio is found to be less than 1 for Kachchh and Mainland Gujarat regions and close to unity for Saurashtra region. This reflects the difference in the geological composition of rocks in the regions. The frequency dependent relations developed in this study could be used for the estimation of earthquake source parameters as well as for simulating the strong earthquake ground motions in the region.

  19. Fault zone exploration in a geothermal context using P- and S-wave measurements

    NASA Astrophysics Data System (ADS)

    Wawerzinek, Britta; Buness, Hermann; Musmann, Patrick; Tanner, David C.; Krawczyk, Charlotte M.; Thomas, Rüdiger

    2015-04-01

    In the framework of the collaborative research programme gebo ('Geothermal Energy and High Performance Drilling') we applied seismic P- and S-wave measurements to analyse and characterise fault zones. Fault zones have a high potential for geothermal energy extraction, but their usability depends on complex factors (structure, lithology, tectonics), underlining the need for detailed fault zone exploration and the deeper understanding of the factors' interplay. In this study, we carried out both P- and S-wave reflection seismic surveys parallel and perpendicular to the eastern border of the Leinetal Graben, Lower Saxony, to explore the fault system. The seismic data reveal a high-resolution image of the complex graben structure which comprises both steeply-dipping normal faults and shallowly west-dipping normal faults, which cause a roll-over structure. In addition halokinesis is observed. The structural image of the graben structure indicates independent tectonic development of the uppermost (<500 m) and deeper (>500 m) depth levels. One of the shallowly west-dipping normal faults is traceable from the surface down to 500 m depth. To further investigate this fault zone which shows different reflection characteristics of P- and S-waves, a petrophysical analysis was conducted, including elastic parameter derivation and seismic modelling. Elastic parameters change strongly in the near-surface area, e.g., vs increases from 300 m/s at the surface to 900 m/s at 100 m depth, leading to a decrease in vp/vs from 6 to approx. 2.5. Changes in elastic parameters correlate with the geological interpretation and are in correspondence to literature values for the given lithologies. However, the fault zone itself shows no significant changes in elastic parameters due to the low resolution of the derived seismic velocities. Seismic modelling is a helpful tool to check elastic parameters which are assigned to the fault zone in the model. A comparison between synthetic and field data

  20. Optimized {gamma}-Multiplicity Based Spin Assignments of s-Wave Neutron Resonances

    SciTech Connect

    Becvar, F.; Koehler, Paul Edward; Krticka, Milan; Mitchell, G. E.; Ullmann, J. L.

    2011-01-01

    The multiplicity of -ray emission following neutron capture at isolated resonances carries valuable information on the resonance spin. Several methods utilizing this information have been developed. The latest method was recently introduced for analyzing the data from time-of-flight measurements with 4 -calorimetric detection systems. The present paper describes a generalization of this method. The goal is the separation of the -emission yields belonging to the two neutron capturing state spins of isolated (or even unresolved) s-wave neutron resonances on targets with non-zero spin. The formalism for performing this separation is described and then tested on artificially generated data. This new method was applied to the -multiplicity data obtained for the 147Sm(n, )148Sm reaction using the DANCE detector system at the LANSCE facility at Los Alamos National Laboratory. The analyzing power of the upgraded method is supported by combined dicebox and geant4 simulations of the fluctuation properties of the multiplicity distributions.

  1. Energy space entanglement spectrum of pairing models with s-wave and p-wave symmetry

    NASA Astrophysics Data System (ADS)

    Rodríguez-Laguna, Javier; Berganza, Miguel Ibáñez; Sierra, Germán

    2014-07-01

    We study the entanglement between blocks of energy levels in 1D models for s-wave and p-wave superconductivity. The ground state entanglement entropy and entanglement spectrum (ES) of a block of ℓ levels around the Fermi point is obtained and related to its physical properties. In the superconducting phase at large coupling, the maximal entropy grows with the number of levels L as 1/2ln(L). The number of levels presenting maximal entanglement is shown to estimate the number of Cooper pairs involved in pairing correlations. Moreover, the properties of the ES signal the presence of the Read-Green quantum phase transition in the p +ip model, and of the Moore-Read line, which is difficult to characterize. This work establishes a link between physical properties of superconducting phases and quantum entanglement.

  2. Anisotropy in s-wave Bose-Einstein condensate collisions and its relationship to superradiance

    NASA Astrophysics Data System (ADS)

    Deuar, P.; Jaskula, J.-C.; Bonneau, M.; Krachmalnicoff, V.; Boiron, D.; Westbrook, C. I.; Kheruntsyan, K. V.

    2014-09-01

    We report the experimental realization of a single-species atomic four-wave mixing process with Bose-Einstein-condensate collisions for which the angular distribution of scattered atom pairs is not isotropic, despite the collisions being in the s-wave regime. Theoretical analysis indicates that this anomalous behavior can be explained by the anisotropic nature of the gain in the medium. There are two competing anisotropic processes: classical trajectory deflections due to the mean-field potential and Bose-enhanced scattering which bears similarity to superradiance. We analyze the relative importance of these processes in the dynamical buildup of the anisotropic density distribution of scattered atoms and compare the Bose enhancement effects to those in optically pumped superradiance.

  3. The relation between seismic P- and S-wave velocity dispersion in saturated rocks

    SciTech Connect

    Mavko, G.; Jizba, D.

    1994-01-01

    Seismic velocity dispersion in fluid-saturated rocks appears to be dominated by two mechanisms: the large scale mechanism modeled by Biot, and the local flow or squirt mechanism. The two mechanisms can be distinguished by the ratio of P- to S-wave dispersions, or more conveniently, by the ratio of dynamic bulk to shear compliance dispersions derived from the wave velocities. The authors` formulation suggests that when local flow dominates, the dispersion of the shear compliance will be approximately 4/15 the dispersion of the compressibility. When the Biot mechanism dominates, the constant of proportionality is much smaller. Their examination of ultrasonic velocities from 40 sandstones and granites shows that most, but not all, of the samples were dominated by local flow dispersion, particularly at effective pressures below 40 MPa.

  4. Dynamical Generation of Floquet Majorana Flat Bands in s-Wave Superconductors

    NASA Astrophysics Data System (ADS)

    Poudel, Amrit; Ortiz, Gerardo; Viola, Lorenza

    2015-03-01

    We present techniques to dynamically engineer flat bands of symmetry-protected Majorana edge modes in s-wave superconductors. Specifically, we show how time-dependent periodic control may be employed for designing time-independent effective Hamiltonians, which support Floquet Majorana flat bands, starting from topologically trivial equilibrium conditions. In the first approach, a suitably chosen modulation of the chemical potential simultaneously induces Majorana flat bands and dynamically ``activates'' a pre-existing chiral symmetry which is responsible for their protection. In the second approach, a desired chiral symmetry is dynamically generated by suppressing a chirality-breaking term in the static Hamiltonian. In the process, we also show how a non-equilibrium topological state of matter may be reached, that has no known equilibrium counterpart.

  5. Dynamical generation of Floquet Majorana flat bands in s-wave superconductors

    NASA Astrophysics Data System (ADS)

    Poudel, A.; Ortiz, G.; Viola, L.

    2015-04-01

    We present quantum control techniques to engineer flat bands of symmetry-protected Majorana edge modes in s-wave superconductors. Specifically, we show how periodic control may be employed for designing time-independent effective Hamiltonians, which support Floquet Majorana flat bands, starting from equilibrium conditions that are either topologically trivial or only support a Majorana pair per edge. In the first approach, a suitable modulation of the chemical potential simultaneously induces Majorana flat bands and dynamically activates a pre-existing chiral symmetry which is responsible for their protection. In the second approach, the application of effective parity kicks dynamically generates a desired chiral symmetry by suppressing chirality-breaking terms in the static Hamiltonian. Our results demonstrate how the use of time-dependent control enlarges the range of possibilities for realizing gapless topological superconductivity, potentially enabling access to topological states of matter that have no known equilibrium counterpart.

  6. Feshbach enhanced s-wave scattering of fermions: direct observation with optimized absorption imaging

    NASA Astrophysics Data System (ADS)

    Genkina, Dina; Aycock, Lauren; Stuhl, Benjamin; Lu, Hsin-I.; Williams, Ross; Spielman, Ian

    2016-05-01

    We directly measured the normalized s-wave scattering cross-section of ultracold 40 K atoms across a magnetic-field Feshbach resonance by colliding pairs of degenerate Fermi gases (DFGs) and imaging the scattered atoms. We extracted the scattered fraction for a range of bias magnetic fields, and measured the resonance location to be B 0 = 20.206(15) mT with width Δ = 1.0(5) mT. To optimize the signal-to-noise ratio (SNR) of atom number in scattering images, we developed techniques to interpret absorption images in a regime where recoil induced detuning corrections are significant. These imaging techniques are generally applicable to experiments with lighter alkalis that would benefit from maximizing SNR on atom number counting at the expense of spatial imaging resolution.

  7. Single gap s-wave superconductivity in Nb2PdS5

    NASA Astrophysics Data System (ADS)

    Shruti; Goyal, R.; Awana, V. P. S.; Patnaik, S.

    2016-05-01

    Superconducting order parameter and its symmetry are important parameters towards deciphering the pairing mechanism in newly discovered superconducting systems. We report a study on penetration depth measurement on Nb2PdS5 that has recently been reported with extremely high upper critical field with possible triplet pairing mechanism. Our data show that at low temperatures the change in penetration depth Δλ is best fitted with BCS s-wave model for single gap with zero-temperature value of the superconducting energy gap Δ0 = 1.05 meV, corresponding to the ratio 2Δ0/kBTc = 3.9 ± 0.18. The superfluid density in the entire temperature range is well described by single gap with gap ratio 2Δ0/kBTc = 4.1 ± 0.13 for λ(0) = 225 nm.

  8. Neutron capture in s-wave resonances of iron-56, nickel-58, and nickel-60

    SciTech Connect

    Wisshak, K.; Fabbri, F.; Kappeler, F.; Reffo, G.

    1984-02-01

    The neutron capture widths of s-wave resonances in /sup 56/Fe (27.7 keV), /sup 58/Ni (15.4 keV), and /sup 60/Ni (12.5 keV) have been determined using a setup completely different from previous experiments. A pulsed 3-MV Van de Graaff accelerator and a kinematically collimated neutron beam, produced via the /sup 7/Li(p,n) reaction, were used in the experiments. Capture gamma rays were observed by three Moxon-Rae detectors with graphite, bismuth-graphite, and bismuth converters, respectively. The samples were positioned at a neutron flight path of only 9 cm. Thus, events due to capture of resonance-scattered neutrons in the detectors or in surrounding materials are completely discriminated by their additional time of flight. The high neutron flux at the sample position allowed the use of very thin samples (0.15 to 0.45 mm), avoiding large multiple scattering corrections. The data obtained with the individual detectors were corrected for the efficiency of the respective converter materials. For that purpose, detailed theoretical calculations of the capture gamma-ray spectra of the measured isotopes and of gold, which was used as a standard, were performed. The final results are GAMMA /SUB lg/ (27.7 keV, /sup 56/Fe) = 1.06 + or - 0.05 eV; GAMMA..gamma..(15.4 keV, /sup 58/Ni) = 1.53 + or - 0.10 eV; and GAMMA..gamma..(12.5 keV, /sup 60/Ni) = 2.92 + or - 0.19 eV. The accuracy obtained with the present experimental method represents an improvement by a factor 3 to 6 compared to previous experiments. The investigated s-wave resonances contribute 10 to 40% to the total capture rate of the respective isotopes in a typical fast reactor.

  9. Landstreamer Use for Near-Surface P- and S-Wave Velocities and Poisson's Ratio

    NASA Astrophysics Data System (ADS)

    Link, C. A.; Speece, M. A.

    2006-12-01

    Seismic landstreamer use is becomingly increasingly important in shallow seismic investigations where cost or time efficiency is critical. Applications range from locating underground voids to investigating archaeological sites, and recently to determining engineering parameters such as Poisson's ratio and shear modulus. The advantage of a landstreamer is the capability to drag a geophone array from location to location rather than planting individual geophones by hand each time the array is moved. Comparison studies have shown that data quality from landstreamer geophones and conventionally planted spiked geophones is similar and often practically indistinguishable. The Geophysical Engineering Department at Montana Tech has been using seismic landstreamers to aid data collection for projects that use both diving wave tomographic inversion to produce P-wave velocity images and surface wave dispersion inversion to estimate S-wave velocity images. We then use the P-wave and S-wave velocity images to calculate a Poisson's ratio image. All of these are produced from the same set of recorded shot gathers using vertical component, gimbaled geophones in a landstreamer configuration. This combined use of landstreamers and single mode geophones proves to be an extremely efficient method for determining subsurface parameters of interest. We used this approach to image an open-top buried cement structure at a local geophysical test site. The two velocity images and Poisson's ratio image show good agreement with expected values and clearly show the location of the buried structure. We also used this approach to characterize a leaking earthen mine tailings dam. Results from this investigation highlight areas interpreted to be weak zones associated to known leakage locations.

  10. Electron attachment in F2 - Conclusive demonstration of nonresonant, s-wave coupling in the limit of zero electron energy

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Alajajian, S. H.

    1987-01-01

    Dissociative electron attachment to F2 has been observed in the energy range 0-140 meV, at a resolution of 6 meV (full width at half maximum). Results show conclusively a sharp, resolution-limited threshold behavior consistent with an s-wave cross section varying as sq rt of epsilon. Two accurate theoretical calculations predict only p-wave behavior varying as the sq rt of epsilon. Several nonadiabatic coupling effects leading to s-wave behavior are outlined.

  11. Global Upper-Mantle Tomography With the Automated Multimode Inversion of Surface and S Wave Forms

    NASA Astrophysics Data System (ADS)

    Lebedev, S.; van der Hilst, R. D.

    2006-12-01

    We apply the Automated Multimode Inversion (AMI) to a large global dataset, examine the accuracy of our techniques and assumptions, and compute an Sv-velocity model of the upper mantle (crust--660 km) using 61000 seismograms. Structure of the mantle and crust is constrained by waveform information from 306000 time-frequency windows with the fundamental-mode Rayleigh waves (periods from 20 to 400 s) and from windows with 19600 distinct higher-mode wavepackets (S and multiple S wave arrivals). We implement AMI with a 3D reference model; linear equations obtained from all the seismograms of the dataset are inverted for anomalies relative to the 3D reference, in this study composed of a 3D model of the crust and a 1D depth profile in the mantle. Waveform information is related to S- and P-velocity structure within approximate waveform sensitivity areas. Inverting for isotropic variations in S- and P-wave velocities, we also allow for S-wave azimuthal anisotropy---in order to minimize errors due to mapping of anisotropy into isotropic heterogeneity. The lateral resolution of the resulting isotropic upper-mantle images is a few hundred km, varying with data sampling. We validate the imaging technique with a novel, "spectral-element" resolution test: inverting a global synthetic data set computed with the spectral-element method (Capdeville et al. 2003) through a laterally heterogeneous mantle model we are able to reconstruct the synthetic model accurately. This test confirms both the accuracy of the implementation of the method and the validity of the JWKB and path-average approximations as applied in it. Reviewing the tomographic model, we observe that low-Sv-velocity anomalies beneath mid-ocean ridges and back-arc basins extend down to ~100 km depth only; this corresponds to estimates of primary melt production depth ranges there. Seismic lithosphere beneath cratons bottoms at depths up to 200 km. Pronounced low-velocity zones beneath cratonic lithosphere are rare

  12. S wave attenuation and site effects in the region of Friuli, Italy

    NASA Astrophysics Data System (ADS)

    Castro, Raúl R.; Pacor, Francesca; Sala, Alfio; Petrungaro, Carmine

    1996-10-01

    We used strong motion records from the 1976 Friuli earthquake (M 6.4) and 10 of the biggest aftershocks recorded by the National Accelerograph Network of the Electrical Power Company of Italy to estimate the quality factor Q of S waves in this region. The wide distance range of the recordings (10 < r < 190 km) permits us to analyze the spectral amplitude decay of the records using a nonparametric approach [e.g., Anderson and Quaas, 1988; Castro et al., 1990; Anderson, 1991]. We obtained attenuation functions for a set of 18 frequencies ranging between 0.4 and 25.0 Hz. The values of Q retrieved from the attenuation functions obtained follow the frequency-dependent relation Q = 20.4f. A test of the method was made using a second data set consisting of digital seismograms from the Friuli-Venezia Giulia Seismograph Network. In spite of the different size of the volume sampled by these data (10 < r < 131 km), the frequency dependence of Q obtained (Q = 16.1f0.92) is similar to that obtained with the strong motion data set. The near-surface attenuation was also estimated using the model proposed by Anderson and Hough [1984] and Anderson [1991]. We found that κ0 is smaller for the strong motion stations located on rock compared to stations located on either shallow or soft sediments. To estimate the site response of the strong motion stations, we corrected the spectral records for the attenuation effect and then inverted the corrected records to separate source and site effects using the inversion scheme proposed by Andrews [1986]. To verify the site amplification estimates obtained, we also calculated the transfer function of each site using Nakamura's [1989] method for S wave [e.g., Lermo and Chavez-García, 1993]. In general, the shapes of the site functions obtained with the inversion are consistent with the transfer functions obtained calculating the horizontal to vertical component ratio.

  13. INTEGRATING P-WAVE AND S-WAVE SEISMIC DATA TO IMPROVE CHARACTERIZATION OF OIL RESERVOIRS

    SciTech Connect

    Innocent J. Aluka

    2004-12-01

    The data used in this study were acquired by nine-component (9C) vertical seismic profile (VSP), using three orthogonal vector sources. The 9C vertical seismic profile is capable of generating P-wave mode and the fundamental S-wave mode (SH-SH and SV-SV) directly at the source station and permits the basic components of elastic wavefield (P, SH-SH and SV-SV) to be separated from one another for the purposes of imaging. Analysis and interpretations of data from the study area show that incident full-elastic seismic wavefield is capable of reflecting four different wave modes, P, SH , SV and C which can be utilized to fully understand the architecture and heterogeneities of geologic sequences. The conventional seismic stratigraphy utilizes only reflected P-wave modes. The notation SH mode is the same as SH-SH; SV mode means SV-SV and C mode which is a converted shear wave is a special SV mode and is the same as P-SV. These four wave modes image unique geologic stratigraphy and facies and at the same time reflect independent stratal surfaces because of the unique orientation of their particle-displacement vectors. As a result of the distinct orientation of individual mode.s particle-displacement vector, one mode may react to a critical subsurface sequence more than the other. It was also observed that P-wave and S-wave do not always reflect from the same stratal boundaries. At inline coordinate 2100 and crossline coordinates of 10,380, 10430, 10480 and 10,520 the P-wave stratigraphy shows coherency at time slice 796 m/s and C-wave stratigraphy shows coherency at time slice 1964 m/s at the same inline coordinate and crossline coordinates of 10,400 to 10470. At inline coordinate 2800 and crossline coordinate 10,650, P-wave stratigraphy shows coherency at time slice 792 m/s and C-wave stratigraphy shows coherency at time slice 1968 m/s. The utilization of full-elastic seismic wavefield needs to be maximized in oil and gas explorations in order to optimize the search for

  14. 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.

    SciTech Connect

    Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

    2007-06-06

    Velocity measurements in shallow sediments from ground surface to approximately 370 to 400 feet bgs were collected by Redpath Geophysics using impulsive S- and P-wave seismic sources (Redpath 2007). Measurements below this depth within basalt and sedimentary interbeds were made by UTA between October and December 2006 using the T-Rex vibratory seismic source in each of the three boreholes. Results of these measurements including seismic records, wave-arrival identifications and interpreted velocity profiles are presented in the following six volumes: I. P-Wave Measurements in Borehole C4993 II. P-Wave Measurements in Borehole C4996 III. P-Wave Measurements in Borehole C4997 IV. S-Wave Measurements in Borehole C4993 V. S-Wave Measurements in Borehole C4996 VI. S-Wave Measurements in Borehole C4997 In this volume (V), all S-wave measurements are presented that were performed in Borehole C4996 at the WTP with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver.

  15. 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.

    SciTech Connect

    Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

    2007-06-06

    Velocity measurements in shallow sediments from ground surface to approximately 370 to 400 feet bgs were collected by Redpath Geophysics using impulsive S- and P-wave seismic sources (Redpath 2007). Measurements below this depth within basalt and sedimentary interbeds were made by UTA between October and December 2006 using the T-Rex vibratory seismic source in each of the three boreholes. Results of these measurements including seismic records, wave-arrival identifications and interpreted velocity profiles are presented in the following six volumes: I. P-Wave Measurements in Borehole C4993 II. P-Wave Measurements in Borehole C4996 III. P-Wave Measurements in Borehole C4997 IV. S-Wave Measurements in Borehole C4993 V. S-Wave Measurements in Borehole C4996 VI. S-Wave Measurements in Borehole C4997 In this volume (VI), all S-wave measurements are presented that were performed in Borehole C4997 at the WTP with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver.

  16. Analytical testing

    NASA Technical Reports Server (NTRS)

    Flannelly, W. G.; Fabunmi, J. A.; Nagy, E. J.

    1981-01-01

    Analytical methods for combining flight acceleration and strain data with shake test mobility data to predict the effects of structural changes on flight vibrations and strains are presented. This integration of structural dynamic analysis with flight performance is referred to as analytical testing. The objective of this methodology is to analytically estimate the results of flight testing contemplated structural changes with minimum flying and change trials. The category of changes to the aircraft includes mass, stiffness, absorbers, isolators, and active suppressors. Examples of applying the analytical testing methodology using flight test and shake test data measured on an AH-1G helicopter are included. The techniques and procedures for vibration testing and modal analysis are also described.

  17. Spin Hall conductivity in the impure two-dimensional Rashba s-wave superconductor

    NASA Astrophysics Data System (ADS)

    Biderang, M.; Yavari, H.

    2016-06-01

    Based on the Kubo formula approach, the spin Hall conductivity (SHC) of a two-dimensional (2D) Rashba s-wave superconductor in the presence of nonmagnetic impurities is calculated. We will show that by increasing the superconducting gap, the SHC decreases monotonically to zero, while by decreasing the concentration of impurities at zero gap, the SHC closes to the clean limit universal value - e/8 π. As a function of the impurity relaxation rate τ at Tc = 0.1 and γ = 0.01 (γ is the spin-orbit coupling in unit of eV · m), we will show that in the dirty limit (τ → 0) the SHC vanishes, and by increasing the relaxation time (τ → ∞) the SHC depends on the value of superconducting gap (Δ = 1.76Tc√{ 1 -T/Tc }), is changed from zero for full gap to -e/8 π in zero gap. At low temperatures, the SHC goes to zero exponentially and near the critical temperature depending on the concentration of the scattering centers, the SHC will tend to the value of normal state. We will also show that the SHC is independent of spin-orbit coupling (γ) in the clean limit.

  18. Spin-Orbit Coupled s-Wave Superconductor in One-Dimensional Optical Lattice

    NASA Astrophysics Data System (ADS)

    Yang, Li-Jun; Lang, Li-Jun; Lü, Rong; Hu, Hai-Ping

    2015-04-01

    We study the topological properties of spin-orbit coupled s-wave superconductor in one-dimensional optical lattice. Compared to its corresponding continuum model, the single particle spectrum is modified by the optical lattice and the topological phase which is characterized by the Majorana edge modes can survive in two regions of the single-particle spectrum. With the help of the self-consistent Bogoliubov-de Gennes calculation in the harmonic trap, we find that the existence of an upper critical magnetic field removes the topological superconductor phase to the trap wings. We also study the effects of nonmagnetic and magnetic impurity on the topological properties, and find the universal behavior of the mid-gap state induced by impurity in the topological superconductor phase in strong scattering limit. Supported by National Program for Basic Research of MOST (973 grant), and by National Natural Science Foundation of China under Grant Nos. 11121063, 11174360, 11374354, 11274195, 2011CB606405 and 2013CB922000

  19. S-wave attenuation structure beneath the northern Izu-Bonin arc

    NASA Astrophysics Data System (ADS)

    Takahashi, Tsutomu; Obana, Koichiro; Kodaira, Shuichi

    2016-04-01

    To understand temperature structure or magma distribution in the crust and uppermost mantle, it is essential to know their attenuation structure. This study estimated the 3-D S-wave attenuation structure in the crust and uppermost mantle at the northern Izu-Bonin arc, taking into account the apparent attenuation due to multiple forward scattering. In the uppermost mantle, two areas of high seismic attenuation (high Q -1) imaged beneath the volcanic front were mostly colocated with low-velocity anomalies. This coincidence suggests that these high- Q -1 areas in low-velocity zones are the most likely candidates for high-temperature regions beneath volcanoes. The distribution of random inhomogeneities indicated the presence of three anomalies beneath the volcanic front: Two were in high- Q -1 areas but the third was in a moderate- Q -1 area, indicating a low correlation between random inhomogeneities and Q -1. All three anomalies of random inhomogeneities were rich in short-wavelength spectra. The most probable interpretation of such spectra is the presence of volcanic rock, which would be related to accumulated magma intrusion during episodes of volcanic activity. Therefore, the different distributions of Q -1 and random inhomogeneities imply that the positions of hot regions in the uppermost mantle beneath this arc have changed temporally; therefore, they may provide important constraints on the evolutionary processes of arc crust and volcanoes.

  20. Floating potential perturbations due to micrometeoroid impacts: Theory and application to S/WAVES data

    NASA Astrophysics Data System (ADS)

    Zaslavsky, A.

    2015-02-01

    In situ observation of dust grains from various origins is routinely performed by space missions equipped with radio instruments. These measurements consist in observations of voltage pulses or their spectral signature. It has for long been proposed that one of the mechanisms able to produce these pulses is the collection by the spacecraft of electric charges generated by impact ionization. Here for the first time, a complete theoretical model of how pulses are generated by charge collection is proposed. In the solar wind at 1 AU, the pulses are shown to be shaped by local plasma and photoelectron parameters. However, the situation can be different in hotter or denser plasma environments. We use the data provided by the STEREO/WAVES (S/WAVES) radio instrument onboard the twin STEREO spacecraft to validate our model. We find that the observations indeed strongly support the theory. The proposed model is an important step forward, since it makes it possible to reproduce the shape, timescales, and amplitudes of pulses generated by dust impacts in various space environments. Such a model can be used to infer the dust detection abilities of radio instruments onboard different spacecraft and can help the design of dust detection optimized radio instruments for future missions.

  1. Entropy and spin susceptibility of s-wave type-II superconductors near Hc2

    NASA Astrophysics Data System (ADS)

    Kita, Takafumi

    2004-04-01

    A theoretical study is performed on the entropy Ss and the spin susceptibility χs near the upper critical field Hc2 for s-wave type-II superconductors with arbitrary impurity concentrations. The changes of these quantities through Hc2 may be expressed as [Ss(T,B)-Ss(T,0)]/[Sn(T)-Ss(T,0)]=1-αS(1-B/Hc2)≈(B/Hc2)αS, for example, where B is the average flux density and Sn denotes entropy in the normal state. It is found that the slopes αS and αχ at T=0 are identical, connected directly with the zero-energy density of states, and vary from 1.72 in the dirty limit to 0.5 0.6 in the clean limit. This mean-free-path dependence of αS and αχ at T=0 is quantitatively the same as that of the slope αρ(T=0) for the flux-flow resistivity studied previously. The result suggests that Ss(B) and χs(B) near T=0 are convex downward (upward) in the dirty (clean) limit, deviating substantially from the linear behavior ∝B/Hc2. The specific-heat jump at Hc2 also shows fairly large mean-free-path dependence.

  2. Scattering attenuation ratios of P and S waves in elastic media

    NASA Astrophysics Data System (ADS)

    Hong, Tae-Kyung

    2004-07-01

    The variation of scattering attenuation ratios of P and S waves (Q-1P/Q-1S) is investigated in elastic media by using numerical simulations and theoretical expressions based on the first-order Born approximation. Numerical results from stochastic random media (von Karman, exponential, Gaussian) with mild velocity perturbation (10 per cent in this study) are represented well by theoretical attenuation curves with a minimum scattering angle of 60-90°. The level of scattering attenuation ratios is dependent on the velocity ratio (γ=α0/β0) and the type of medium. The change of perturbation in the density introduces a relatively small variation in attenuation ratio. Attenuation ratios are proportional to normalized frequency (fa, frequency-by-correlation length) at the intermediate-frequency range (0.1 km s-1 < fa < 10 km s-1) and determined constant at the high-frequency (fa > 10 km s-1) and low-frequency (fa < 1 km s-1) regimes. The von Karman-type models look appropriate for the representation of small-scale variation in the Earth. The scattering attenuation ratios can be implemented for the investigation of small-scale heterogeneities in the Earth.

  3. Robust sky light polarization detection with an S-wave plate in a light field camera.

    PubMed

    Zhang, Wenjing; Zhang, Xuanzhe; Cao, Yu; Liu, Haibo; Liu, Zejin

    2016-05-01

    The sky light polarization navigator has many advantages, such as low cost, no decrease in accuracy with continuous operation, etc. However, current celestial polarization measurement methods often suffer from low performance when the sky is covered by clouds, which reduce the accuracy of navigation. In this paper we introduce a new method and structure based on a handheld light field camera and a radial polarizer, composed of an S-wave plate and a linear polarizer, to detect the sky light polarization pattern across a wide field of view in a single snapshot. Each micro-subimage has a special intensity distribution. After extracting the texture feature of these subimages, stable distribution information of the angle of polarization under a cloudy sky can be obtained. Our experimental results match well with the predicted properties of the theory. Because the polarization pattern is obtained through image processing, rather than traditional methods based on mathematical computation, this method is less sensitive to errors of pixel gray value and thus has better anti-interference performance. PMID:27140364

  4. S-wave π-K scattering length from lattice QCD

    NASA Astrophysics Data System (ADS)

    Sasaki, Kiyoshi; Ishizuka, Naruhito; Yamazaki, Takeshi; Oka, Makoto

    2009-10-01

    We present the S-wave π-K scattering lengths for both the isospin 1/2 and 3/2 channels evaluated by using the finite size formula. We utilize the Nf=2+1 gauge configurations generated on 32^3 x64 lattice using the Iwasaki gauge action and the O(a)-improved Wilson action at 1/a = 2.17 GeV. The quark masses correspond to mπ = 0.30 - 0.70 GeV. For I=1/2, to separate the effects from excited states, we construct a 2x2 matrix of the time correlation function and diagonalize it. Here, we adopt the two kinds of operators, su and π-K. Our preliminary results show signs of the scattering lengths in agreement with experiment, namely attraction in I=1/2 and repulsion in I=3/2. We investigate the quark-mass dependence of the scattering length and also discuss the limitation of chiral perturbation theory.

  5. Chiral superfluidity with p-wave symmetry from an interacting s-wave atomic Fermi gas.

    PubMed

    Liu, Bo; Li, Xiaopeng; Wu, Biao; Liu, W Vincent

    2014-01-01

    Chiral p-wave superfluids are fascinating topological quantum states of matter that have been found in the liquid (3)He-A phase and arguably in the electronic Sr2RuO4 superconductor. They are fundamentally related to the fractional 5/2 quantum Hall state, which supports fractional exotic excitations. Past studies show that they require spin-triplet pairing of fermions by p-wave interaction. Here we report that a p-wave chiral superfluid state can arise from spin-singlet pairing for an s-wave interacting atomic Fermi gas in an optical lattice. This p-wave state is conceptually distinct from all previous conventional p-wave states as it is for the centre-of-mass motion, instead of the relative motion. It leads to spontaneous generation of angular momentum, finite Chern numbers and topologically protected chiral fermionic zero modes bounded to domain walls, all occuring at a higher critical temperature in relative scales. Signature quantities are predicted for the cold atom experimental condition. PMID:25266996

  6. The I=2 ππ S-wave Scattering Phase Shift from Lattice QCD

    DOE PAGESBeta

    Beane, S. R.; Chang, E.; Detmold, W.; Lin, H. W.; Luu, T. C.; Orginos, K.; Parreno, A.; Savage, M. J.; Torok, A.; Walker-Loud, A.

    2012-02-16

    The π+π+ s-wave scattering phase-shift is determined below the inelastic threshold using Lattice QCD. Calculations were performed at a pion mass of mπ ≈ 390 MeV with an anisotropic nf = 2+1 clover fermion discretization in four lattice volumes, with spatial extent L ≈ 2.0, 2.5, 3.0 and 3.9 fm, and with a lattice spacing of bs ≈ 0.123 fm in the spatial direction and bt bs/3.5 in the time direction. The phase-shift is determined from the energy-eigenvalues of π+π+ systems with both zero and non-zero total momentum in the lattice volume using Luscher's method. Our calculations are precise enoughmore » to allow for a determination of the threshold scattering parameters, the scattering length a, the effective range r, and the shape-parameter P, in this channel and to examine the prediction of two-flavor chiral perturbation theory: mπ2 a r = 3+O(mπ2/Λχ2). Chiral perturbation theory is used, with the Lattice QCD results as input, to predict the scattering phase-shift (and threshold parameters) at the physical pion mass. Our results are consistent with determinations from the Roy equations and with the existing experimental phase shift data.« less

  7. Multi-component elastic reverse time migration based on the P- and S-wave separated velocity-stress equations

    NASA Astrophysics Data System (ADS)

    Gu, Bingluo; Li, Zhiyuan; Ma, Xiaona; Liang, Guanghe

    2015-01-01

    The vector P- and S-seismograms in an elastic common-shot gather generated with a P-wave source in a two-dimensional model using a finite difference solution of the P- and S-wave separated velocity-stress equations can be imaged by two independent ERTMs based on the same equations. The inputs as boundary conditions for reverse-time extrapolation are the pure vector P- and S-waves, respectively. The vector P-wave image components can be obtained by the normalized correlation operation between the vector P-source wavefields and receiver wavefields, which are obtained by extrapolating the vector P-seismograms in reverse-time using the same equations as the forward modeling. The vector S-wave image components can be obtained by a similar method. Compared with the conventional ERTM, this method can minimize the artifacts caused by the crosstalk between different wave modes and can preserve the phase and amplitude attributes of migration images very well. Furthermore, the polarity-reversal of the vector S-wave data can be corrected automatically during the imaging process, so destructive interferences between data from adjacent sources do not exist. Numerical examples with synthetic data have demonstrated the feasibility and effectiveness of this method for complex structures.

  8. Frequency-wavenumber implementation for P- and S-wave separation from multi-component seismic data

    NASA Astrophysics Data System (ADS)

    Li, Zhiyuan; Ma, Xiaona; Fu, Chao; Gu, Bingluo; Liang, Guanghe

    2016-03-01

    In this paper, we present a frequency-wavenumber domain scheme to separate P- and S-waves from multi-component seismic data at the free surface. Based on the relationship between the P- and S-wave separated elastic equation, and the divergence and curl operators, we modify the equation to make it applicable to surface seismic data. In the modified equation, the P-wavenumber is chosen to reject the P-waves, and the S-wavenumber is chosen to eliminate the S-waves. The changes in the P-S amplitude ratio caused by the wavenumber choice are corrected. For the free surface condition, an up-going wavefield separation filter is introduced into the modified equation, which can remove the free surface effects from the surface seismic data. In the case of a free surface exhibiting lateral heterogeneity, the seismic data are first transformed into the frequency domain using the fast Fourier transform (FFT), and then are transformed into the wavenumber domain using the discrete Fourier transform (DFT). In the second transform using the DFT, the modified equation is used to separate the P- and S-waves. Numerical tests on synthetic data for three models demonstrate the good performance and accuracy of the scheme.

  9. Numerical solution of the time dependent Ginzburg-Landau equations for mixed (d + s)-wave superconductors

    SciTech Connect

    Gonçalves, W. C.; Sardella, E.; Becerra, V. F.; Milošević, M. V.; Peeters, F. M.

    2014-04-15

    The time-dependent Ginzburg-Landau formalism for (d + s)-wave superconductors and their representation using auxiliary fields is investigated. By using the link variable method, we then develop suitable discretization of these equations. Numerical simulations are carried out for a mesoscopic superconductor in a homogeneous perpendicular magnetic field which revealed peculiar vortex states.

  10. Form factors and the s-wave component of the two-pion-exchange three-nucleon potential

    SciTech Connect

    Robilotta, M.R.; Isidro Filho, M.P.; Coelho, H.T.; Das, T.K.

    1985-02-01

    We argue that the straightforward introduction of ..pi..N form factors into the s-wave component of the two-pion-exchange three-nucleon potential based on chiral symmetry is not free of problems. These can be avoided by means of a redefinition of the potential which considers its physical content.

  11. Distinct S wave reflector in the midcrust beneath Nikko-Shirane volcano in the northeastern Japan arc

    SciTech Connect

    Matsumoto, Satoshi; Hasegawa, Akira

    1996-02-10

    This paper investigates the geometry and the features of the midcrustal s wave reflector beneath Nikko-Shirane valcano in detail based on data acquired through seismic observations with a dense station network. The geometry and internal structure of the reflector is discribed.

  12. Frequency content of P and S wave travel time measurements and chemical heterogeneity in the lower mantle

    NASA Astrophysics Data System (ADS)

    Houser, C. T.

    2012-12-01

    Recently it was proposed by Schuberth et al., (GJI, 2012) that the difference in the magnitude of P and S delay times from the large low shear velocity provinces (LLSVP) can be explained by differences in their frequency content. They produced synthetic seismograms using the spectral element method (SEM) and measured travel times using an automated cross correlation technique through a synthetic 3D Earth model based solely on temperature variations. They found a similar difference in the magnitude of P and S travel time variations for their isochemical model as the real Earth and suggest that it is the nature of the cross correlation analysis that results in different P and S wave delay times, not the Earth's material properties. Their preferred explanation is two-fold: 1) that the P waves are front loaded with higher frequencies and 2) that for the same frequency, P waves have a larger Fréchet kernel and thus different wavefront healing characteristics than S waves for the same structure. Here, I demonstrate that the observed long period P waves are no more front loaded in frequency than S waves when cluster analysis is applied. I compare the travel times of P and S waves for events sweeping across the Pacific lower mantle recorded at the numerous USArray stations. I apply the cluster analysis method (Houser et al., GJI, 2008) and a manual cross correlation method (Bolton and Masters, JGR, 2001) method to the long-period (~25s) as well as shorter period (~15s) observed and synthetic seismograms. If the notion of Schuberth et al. were correct, then the observed P-wave pulse would be compressed at the onset, e.g. front loaded in frequency, and then spread out toward the back end. In this case, a cross correlation made based on the first swing of the pulse would result in a different travel time than a cross correlation based on the highest amplitude swing in the middle of the P wave. However, I find that for both P and S waves, the highest quality waveforms are

  13. Nature of deep crustal structures of the northeastern Gulf of Aden margin inferred from S-wave modeling

    NASA Astrophysics Data System (ADS)

    Watremez, L.; Leroy, S.; D'Acremont, E.

    2011-12-01

    The Encens cruise (Feb.-March 2006, Leroy et al., 2010) allowed for the acquisition of a large refraction/wide-angle reflection dataset along the northeastern Gulf of Aden margin, between the first order segmentation of the gulf defined by Alula-Fartak and Socotra-Hadbeen fracture zones. A second order segmentation divides this margin into three parts, from west to east: Ashawq-Salalah, Taqah and Mirbat segments. P-wave velocity modeling already allows us to image crustal thinning and structures from the continental to the oceanic crust, and to identify a lower crustal intermediate body on the Ashawq-Salalah segment at the base of the transitional and oceanic crusts. This intermediate body has been interpreted as mafic , and linked to a post-rift thermal anomaly. The instruments, which have been deployed on the Ashawq-Salalah segment, were recording shots on 4-components. Data show good quality S-wave converted arrivals in the transitional and oceanic crust. After picking and modeling of these arrivals, we have identified two families of converted waves:: (1) P-waves converted to S-waves at the basement interface on the way up, and (2) P-waves converted to S-waves at the basement on the way down and traveling through deep structures as shear-waves. The first family provides constraints on the S-wave velocities in the sediment layer while the second family constrains S-wave velocities in the transitional and oceanic crust. The Poisson ratio in the intermediate body (0.285) together with the P-wave velocity (7.7 km/s) and density (3.1 kg/m3) confirms its mafic nature. Furthermore, this study provides more information on the nature of the ocean-continent transition crust and its variations along the northeastern Gulf of Aden margin from a thermally affected segment to a tectonically influenced one.

  14. Determination of elastic anisotropy of rocks from P- and S-wave velocities: numerical modelling and lab measurements

    NASA Astrophysics Data System (ADS)

    Svitek, Tomáš; Vavryčuk, Václav; Lokajíček, Tomáš; Petružálek, Matěj

    2014-12-01

    The most common type of waves used for probing anisotropy of rocks in laboratory is the direct P wave. Information potential of the measured P-wave velocity, however, is limited. In rocks displaying weak triclinic anisotropy, the P-wave velocity depends just on 15 linear combinations of 21 elastic parameters, called the weak-anisotropy parameters. In strong triclinic anisotropy, the P-wave velocity depends on the whole set of 21 elastic parameters, but inversion for six of them is ill-conditioned and these parameters are retrieved with a low accuracy. Therefore, in order to retrieve the complete elastic tensor accurately, velocities of S waves must also be measured and inverted. For this purpose, we developed a lab facility which allows the P- and S-wave ultrasonic sounding of spherical rock samples in 132 directions distributed regularly over the sphere. The velocities are measured using a pair of P-wave sensors with the transmitter and receiver polarized along the radial direction and using two pairs of S-wave sensors with the transmitter and receiver polarized tangentially to the spherical sample in mutually perpendicular directions. We present inversion methods of phase and ray velocities for elastic parameters describing general triclinic anisotropy. We demonstrate on synthetic tests that the inversion becomes more robust and stable if the S-wave velocities are included. This applies even to the case when the velocity of the S waves is measured in a limited number of directions and with a significantly lower accuracy than that of the P wave. Finally, we analyse velocities measured on a rock sample from the Outokumpu deep drill hole, Finland. We present complete sets of elastic parameters of the sample including the error analysis for several levels of confining pressure ranging from 0.1 to 70 MPa.

  15. Analytical Microscopy

    SciTech Connect

    Not Available

    2006-06-01

    In the Analytical Microscopy group, within the National Center for Photovoltaic's Measurements and Characterization Division, we combine two complementary areas of analytical microscopy--electron microscopy and proximal-probe techniques--and use a variety of state-of-the-art imaging and analytical tools. We also design and build custom instrumentation and develop novel techniques that provide unique capabilities for studying materials and devices. In our work, we collaborate with you to solve materials- and device-related R&D problems. This sheet summarizes the uses and features of four major tools: transmission electron microscopy, scanning electron microscopy, the dual-beam focused-ion-beam workstation, and scanning probe microscopy.

  16. 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.

    SciTech Connect

    Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

    2007-06-06

    In this volume (IV), all S-wave measurements are presented that were performed in Borehole C4993 at the Waste Treatment Plant (WTP) with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver. S-wave measurements were performed over the depth range of 370 to 1300 ft, typically in 10-ft intervals. However, in some interbeds, 5-ft depth intervals were used, while below about 1200 ft, depth intervals of 20 ft were used. Shear (S) waves were generated by moving the base plate of T-Rex for a given number of cycles at a fixed frequency as discussed in Section 2. This process was repeated so that signal averaging in the time domain was performed using 3 to about 15 averages, with 5 averages typically used. In addition, a second average shear wave record was recorded by reversing the polarity of the motion of the T-Rex base plate. In this sense, all the signals recorded in the field were averaged signals. In all cases, the base plate was moving perpendicular to a radial line between the base plate and the borehole which is in and out of the plane of the figure shown in Figure 1.1. The definition of “in-line”, “cross-line”, “forward”, and “reversed” directions in items 2 and 3 of Section 2 was based on the moving direction of the base plate. In addition to the LBNL 3-D geophone, called the lower receiver herein, a 3-D geophone from Redpath Geophysics was fixed at a depth of 22 ft in Borehole C4993, and a 3-D geophone from the University of Texas (UT) was embedded near the borehole at about 1.5 ft below the ground surface. The Redpath geophone and the UT geophone were properly aligned so that one of the horizontal components in each geophone was aligned with the direction of horizontal shaking of the T-Rex base plate. This volume is organized into 12 sections as follows. Section 1: Introduction, Section 2: Explanation of Terminology, Section 3: Vs Profile at Borehole C4993

  17. Dynamics of nanoparticules detected at 1 AU by S/WAVES onboard STEREO spacecraft

    NASA Astrophysics Data System (ADS)

    Belheouane, Soraya; Issautier, Karine; Meyer-Vernet, Nicole; Le Chat, Gaétan; Czechowski, Andrzej; Zaslavsky, Arnaud; Zouganelis, Yannis; Mann, Ingrid

    In order to interpret in detail the S/WAVES data on the interplanetary nanodust discovered by STEREO at 1 AU [Meyer-Vernet et al., 2009], we study the dynamics of nanoparticles in the inner interplanetary medium as well as the distribution of their velocities and directions of arrival, with a model based on [Czechowski and Mann, 2012]. We deduce the charges released by their impacts on the STEREO spacecraft at 1 AU and their dependence on the position of the spacecraft on their orbits. The model studies nanoparticles of size equal or smaller than about 70 nm, assumed to be created via collisional fragmentation of dust grains of larger size moving on keplerian orbits, and sublimation of dust, meteoroids and comets. The nanoparticles are released near the Sun with initial velocities close to keplerian, and mainly subjected to the Lorentz force calculated with a simple solar wind model. A part of the nanoparticles is accelerated to high speeds of the order of 300 km/s, thereby providing impact charges between 10(-14) and 10(-11) Cb [Belheouane, 2014] which enable them to be detected by S/WAVES, whereas another part is trapped within about 0.2 AU from the Sun. We discuss how the fluxes and direction of arrival at 1 AU are expected to change in function of the solar cycle. These results enable us to interpret in detail the STEREO/WAVES observations [Zaslavsky et al., 2012]; [Pantellini et al., 2013]; [Le Chat et al., 2013]. Belheouane, S. (2014). Nanoparticules dans le vent solaire, observations spatiales et theorie. PhD thesis, Pierre and Marie Curie University UPMC. Czechowski, A. and Mann, I. (2012). Nanodust Dynamics in Interplanetary Space, chapter Nanodust Dynamics in Interplanetary Space. Springer Berlin Heidelberg. Le Chat, G., Zaslavsky, A., Meyer-Vernet, N., Issautier, K., Belheouane, S., Pantellini, F., Maksimovic, M., Zouganelis, I., Bale, S., and Kasper, J. (2013). Interplanetary Nanodust Detection by the Solar Terrestrial Relations Observatory/WAVES Low

  18. STEREO SECCHI Observations of Space Debris: Are They Associated with S/WAVES Dust Detections?

    NASA Astrophysics Data System (ADS)

    St. Cyr, O. C.; Howard, R. A.; Wang, D.; Thompson, W. T.; Harrison, R. A.; Kaiser, M. L.

    2007-12-01

    White-light coronagraphs are optimized to reject stray light in order to accomplish their primary science objective - - the observation of coronal mass ejections (CMEs) and the corona. Because they were designed to detect these faint signals while pointing at the Sun, many spacebased coronagraphs in the past (Skylab, SMM, SOHO) have detected "debris" apparently associated with the vehicle. These appear to be sunlit particles very near the front of the telescope aperture (~meters). In at least one case, these earlier debris sightings were interpreted as deteriorating insulation from the thermal blankets on the spacecraft (St. Cyr and Warner, 1991ASPC...17..126S); and for the earlier Sklyab observations, the sightings were believed to be associated with water droplets (Eddy, "A New Sun: The Solar Results from Skylab", NASA SP-402, p119, 1979.) The STEREO SECCHI suite of white-light coronagraphs represents the most recent instantations of these specialized instruments, and for the first time we are able to track CMEs from their initiation at the Sun out to 1 A.U. Since observations commenced, the SECCHI white-light telescopes have been sporadically detecting debris particles. Most of the detections are individual or small numbers of bright objects in the field which therefore do not affect the primary science goals of the mission. But on several occasions in the eight months' of observation there have been "swarms" of these bright objects which completely obscure the field of view of one or more instrument for a brief period of time. Here we report on the intriguing possibility that the SECCHI debris sightings represent particles of thermal insulation, ejected from the spacecraft by interplanetary dust impacts. Because of the large field of view and high duty cycle of the Heliospheric Imagers on STEREO, we may be able to demonstrate that some of these have also been detected by STEREO S/WAVES as sporadic plasma emissions.

  19. Interpretation of S waves generated by near-surface chemical explosions at SAFOD

    USGS Publications Warehouse

    Pollitz, Fred F.; Ellsworth, William L.; Rubinstein, Justin L.

    2015-01-01

    A series of near-surface chemical explosions conducted at the San Andreas Fault Observatory at Depth (SAFOD) were recorded by high-frequency downhole receiver arrays in separate experiments in November 2003 and May 2005. The 2003 experiment involved ∼100  kg shots detonated along a 46-km-long line (Hole–Ryberg line) centered on SAFOD and recorded by 32 three-component geophones in the pilot hole between 0.8 and 2.0 km depth. The 2005 experiment involved ∼36  kg shots detonated at Parkfield Area Seismic Observatory (PASO) stations (at ∼1–8  km offset) recorded by 80 three-component geophones in the main hole between the surface and 2.4 km depth. These data sample the downgoing seismic wavefield and constrain the shallow velocity and attenuation structure, as well as the first-order characteristics of the source. Using forward modeling on a velocity structure designed for the near field, both observed P- and S-wave energy for the PASO shots are identified with the travel times expected for direct and/or reflected phases. Larger-offset recordings from shots along the Hole–Ryberg line reveal substantial SV and SH energy, especially southwest of SAFOD from the source as indicated by P-to-S amplitude ratios. The generated SV energy is interpreted to arise chiefly from P-to-S conversions at subhorizontal discontinuities. This provides a simple mechanism for often-observed low P-to-S amplitude ratios from nuclear explosions in the far field, as originating from strong near-field wave conversions.

  20. Quantum quench phase diagrams of an s -wave BCS-BEC condensate

    NASA Astrophysics Data System (ADS)

    Yuzbashyan, E. A.; Dzero, M.; Gurarie, V.; Foster, M. S.

    2015-03-01

    We study the dynamic response of an s -wave BCS-BEC (atomic-molecular) condensate to detuning quenches within the two-channel model beyond the weak-coupling BCS limit. At long times after the quench, the condensate ends up in one of three main asymptotic states (nonequilibrium phases), which are qualitatively similar to those in other fermionic condensates defined by a global complex order parameter. In phase I the amplitude of the order parameter vanishes as a power law, in phase II it goes to a nonzero constant, and in phase III it oscillates persistently. We construct exact quench phase diagrams that predict the asymptotic state (including the many-body wave function) depending on the initial and final detunings and on the Feshbach resonance width. Outside of the weak-coupling regime, both the mechanism and the time dependence of the relaxation of the amplitude of the order parameter in phases I and II are modified. Also, quenches from arbitrarily weak initial to sufficiently strong final coupling do not produce persistent oscillations in contrast to the behavior in the BCS regime. The most remarkable feature of coherent condensate dynamics in various fermion superfluids is an effective reduction in the number of dynamic degrees of freedom as the evolution time goes to infinity. As a result, the long-time dynamics can be fully described in terms of just a few new collective dynamical variables governed by the same Hamiltonian only with "renormalized" parameters. Combining this feature with the integrability of the underlying (e.g., the two-channel) model, we develop and consistently present a general method that explicitly obtains the exact asymptotic state of the system.

  1. Craton Development and Stabilization: Insights from SE Canada using P and S Wave Tomography

    NASA Astrophysics Data System (ADS)

    Boyce, A.; Bastow, I. D.; Darbyshire, F. A.; Gilligan, A.; Ellwood, A.; Levin, V. L.; Menke, W. H.

    2015-12-01

    Cratons, the ancient cores of the continents, are the longest-lived parts of Earth's surface that have survived thermal and mechanical erosion during multiple Wilson cycles. They are visible in tomographic images due to their thick (>200km), seismically fast keels or roots. The Laurentian keel beneath North America is intriguing since its root is thought to extend beneath both the Archean Superior craton and the Proterozoic Grenville province thus implying that keel formation may not have been restricted to Archean times. In order to address this issue we present a P and S wave relative arrival-time tomographic study using data from seismograph networks in SE Canada and the NE US, stretching from the southern tip of Hudson Bay within the Superior craton to the coastal Phanerozoic Appalachian terranes. The tomographic images display three broad zones of increasing mantle wavespeed from globally "slow" in the Appalachian terranes, to a "fast" Grenville Province and "extremely fast" Superior craton. We observe a linear low-velocity feature resulting from modification of the Laurentian keel by the passage of the Great Meteor hotspot. This feature is progressively offset southwestward with depth, potentially due to viscous coupling with mantle flow. No major plate-scale underthrusting during the Grenville Orogeny is apparent, which contradicts the inferred results from crustal seismic reflection and refraction studies. Our results therefore may have fundamental implications for the nature of the Grenville orogenic collision and cratonic stabilization of North America. The results also support the developing consensus that keels form in two stages: a chemically depleted core of Archean age followed by a thermally developed, less-depleted lithosphere during Proterozoic times, highlighted by an abrupt wavespeed contrast in the tomographic images.

  2. Significantly Improving Regional Seismic Amplitude Tomography at Higher Frequencies by Determining S -Wave Bandwidth

    DOE PAGESBeta

    Fisk, Mark D.; Pasyanos, Michael E.

    2016-05-03

    Characterizing regional seismic signals continues to be a difficult problem due to their variability. Calibration of these signals is very important to many aspects of monitoring underground nuclear explosions, including detecting seismic signals, discriminating explosions from earthquakes, and reliably estimating magnitude and yield. Amplitude tomography, which simultaneously inverts for source, propagation, and site effects, is a leading method of calibrating these signals. A major issue in amplitude tomography is the data quality of the input amplitude measurements. Pre-event and prephase signal-to-noise ratio (SNR) tests are typically used but can frequently include bad signals and exclude good signals. The deficiencies ofmore » SNR criteria, which are demonstrated here, lead to large calibration errors. To ameliorate these issues, we introduce a semi-automated approach to assess the bandwidth of a spectrum where it behaves physically. We determine the maximum frequency (denoted as Fmax) where it deviates from this behavior due to inflections at which noise or spurious signals start to bias the spectra away from the expected decay. We compare two amplitude tomography runs using the SNR and new Fmax criteria and show significant improvements to the stability and accuracy of the tomography output for frequency bands higher than 2 Hz by using our assessments of valid S-wave bandwidth. We compare Q estimates, P/S residuals, and some detailed results to explain the improvements. Lastly, for frequency bands higher than 4 Hz, needed for effective P/S discrimination of explosions from earthquakes, the new bandwidth criteria sufficiently fix the instabilities and errors so that the residuals and calibration terms are useful for application.« less

  3. The I=2 ππ S-wave Scattering Phase Shift from Lattice QCD

    SciTech Connect

    Beane, S. R.; Chang, E.; Detmold, W.; Lin, H. W.; Luu, T. C.; Orginos, K.; Parreno, A.; Savage, M. J.; Torok, A.; Walker-Loud, A.

    2012-02-16

    The π+π+ s-wave scattering phase-shift is determined below the inelastic threshold using Lattice QCD. Calculations were performed at a pion mass of mπ ≈ 390 MeV with an anisotropic nf = 2+1 clover fermion discretization in four lattice volumes, with spatial extent L ≈ 2.0, 2.5, 3.0 and 3.9 fm, and with a lattice spacing of bs ≈ 0.123 fm in the spatial direction and bt bs/3.5 in the time direction. The phase-shift is determined from the energy-eigenvalues of π+π+ systems with both zero and non-zero total momentum in the lattice volume using Luscher's method. Our calculations are precise enough to allow for a determination of the threshold scattering parameters, the scattering length a, the effective range r, and the shape-parameter P, in this channel and to examine the prediction of two-flavor chiral perturbation theory: mπ2 a r = 3+O(mπ2χ2). Chiral perturbation theory is used, with the Lattice QCD results as input, to predict the scattering phase-shift (and threshold parameters) at the physical pion mass. Our results are consistent with determinations from the Roy equations and with the existing experimental phase shift data.

  4. S-Wave Velocities of the Lithosphere-Asthenosphere System in the Caribbean Region

    NASA Astrophysics Data System (ADS)

    González, O'leary F.; Alvarez, José Leonardo; Moreno, Bladimir; Panza, Giuliano F.

    2012-01-01

    An overview of the S-wave velocity ( V s) structural model of the Caribbean with a resolution of 2° × 2° is presented. New tomographic maps of Rayleigh wave group velocity dispersion at periods ranging from 10 to 40 s were obtained as a result of the frequency time analysis of seismic signals of more than 400 ray-paths in the region. For each cell of 2° × 2°, group velocity dispersion curves were determined and extended to 150 s by adding data from a larger scale tomographic study ( Vdovin et al., Geophys. J. Int 136:324-340, 1999). Using, as independent a priori information, the available geological and geophysical data of the region, each dispersion curve has been inverted by the "hedgehog" non-linear procedure ( Valyus, Determining seismic profiles from a set of observations (in Russian), Vychislitielnaya Seismologiya 4, 3-14. English translation: Computational Seismology (V.I. Keylis-Borok, ed.) 4:114-118, 1968), in order to compute a set of V s versus depth models up to 300 km of depth. Because of the non-uniqueness of the solutions for each cell, a local smoothness optimization has been applied to the whole region in order to choose a three-dimensional model of V s, satisfying this way the Occam's razor concept. Several known and some new main features of the Caribbean lithosphere and asthenosphere are shown on these models such as: the west directed subduction zone of the eastern Caribbean region with a clear mantle wedge between the Caribbean lithosphere and the subducted slab; the complex and asymmetric behavior of the crustal and lithospheric thickness in the Cayman ridge; the predominant oceanic crust in the region; the presence of continental type crust in Central America, and the South and North America plates; as well as the fact that the bottom of the upper asthenosphere gets shallower going from west to east.

  5. Analytical Searching.

    ERIC Educational Resources Information Center

    Pappas, Marjorie L.

    1995-01-01

    Discusses analytical searching, a process that enables searchers of electronic resources to develop a planned strategy by combining words or phrases with Boolean operators. Defines simple and complex searching, and describes search strategies developed with Boolean logic and truncation. Provides guidelines for teaching students analytical…

  6. Non-relativistic s-wave binding energies of Λ-particle in hypernuclei

    NASA Astrophysics Data System (ADS)

    Armat, A.; Hassanabadi, H.

    2016-04-01

    In this work, the ground state binding energy of Λ-particle in hypernuclei is investigated by using analytical solution of non-relativistic Schrödinger equation in the presence of a generalized Woods-Saxon-type interaction. The comparison with the experimental data is motivating.

  7. Observability of surface Andreev bound states in a topological insulator in proximity to an s-wave superconductor.

    PubMed

    Snelder, M; Golubov, A A; Asano, Y; Brinkman, A

    2015-08-12

    To guide experimental work on the search for Majorana zero-energy modes, we calculate the superconducting pairing symmetry of a three-dimensional topological insulator in combination with an s-wave superconductor. We show how the pairing symmetry changes across different topological regimes. We demonstrate that a dominant p-wave pairing relation is not sufficient to realise a Majorana zero-energy mode useful for quantum computation. Our main result is the relation between odd-frequency pairing and Majorana zero energy modes by using Green functions techniques in three-dimensional topological insulators in the so-called Majorana regime. We discuss thereafter how the pairing relations in the different regimes can be observed in the tunneling conductance of an s-wave proximised three-dimensional topological insulator. We discuss the necessity to incorporate a ferromagnetic insulator to localise the zero-energy bound state to the interface as a Majorana mode. PMID:26189576

  8. Mantle seismic structure beneath the MELT region of the east pacific rise from P and S wave tomography

    PubMed

    Toomey; Wilcock; Solomon; Hammond; Orcutt

    1998-05-22

    Relative travel time delays of teleseismic P and S waves, recorded during the Mantle Electromagnetic and Tomography (MELT) Experiment, have been inverted tomographically for upper-mantle structure beneath the southern East Pacific Rise. A broad zone of low seismic velocities extends beneath the rise to depths of about 200 kilometers and is centered to the west of the spreading center. The magnitudes of the P and S wave anomalies require the presence of retained mantle melt; the melt fraction near the rise exceeds the fraction 300 kilometers off axis by as little as 1%. Seismic anisotropy, induced by mantle flow, is evident in the P wave delays at near-vertical incidence and is consistent with a half-width of mantle upwelling of about 100 km. PMID:9596567

  9. Local earthquake (LE) tomography with joint inversion for P- and S-wave velocities using structural constraints

    NASA Astrophysics Data System (ADS)

    Tryggvason, Ari; Linde, Niklas

    2006-04-01

    In local earthquake (LE) tomography for P- and S-wave velocities (or Vp/Vs ratios), constraints punishing deviations from a given Vp/Vs ratio are often used. In a synthetic model test we demonstrate that though such constraints inhibit unreasonable Vp/Vs ratio variations, they bias the resulting Vp/Vs ratios. As an alternative approach, structural constraints based on the cross-product of the model gradients can be used to constrain the joint P- and S-wave inversion. We show that the resulting models are as low in artifacts as if a Vp/Vs damping was used, but the resulting Vp/Vs ratios are less biased, which is important for a quantitative interpretation of physical properties and processes in the Earth.

  10. Analytical sedimentology

    SciTech Connect

    Lewis, D.W. . Dept. of Geology); McConchie, D.M. . Centre for Coastal Management)

    1994-01-01

    Both a self instruction manual and a cookbook'' guide to field and laboratory analytical procedures, this book provides an essential reference for non-specialists. With a minimum of mathematics and virtually no theory, it introduces practitioners to easy, inexpensive options for sample collection and preparation, data acquisition, analytic protocols, result interpretation and verification techniques. This step-by-step guide considers the advantages and limitations of different procedures, discusses safety and troubleshooting, and explains support skills like mapping, photography and report writing. It also offers managers, off-site engineers and others using sediments data a quick course in commissioning studies and making the most of the reports. This manual will answer the growing needs of practitioners in the field, either alone or accompanied by Practical Sedimentology, which surveys the science of sedimentology and provides a basic overview of the principles behind the applications.

  11. Upper mantle temperatures and lithospheric thickness of North China inferred from S-wave tomography

    NASA Astrophysics Data System (ADS)

    Xiong, X.; Yang, S.; Zheng, Y.

    2013-12-01

    Temperature is one of the most important key parameters which control the density, viscosity, and rheology of the earth's material and hence the dynamic process of the mantle. Based on the correlation between mineral temperature and seismic velocity structure, we derive the upper mantle temperatures of North China in the depth range of 50 to 300 km by high-resolution S-wave tomography model. Defining the depth where the geotherm intersects the mantle adiabat with a potential temperature of 1300°C as the lithosphere-asthenosphere boundary, we estimate the correspondent lithospheric thickness in the north China. The calculated heat flows agree well with the observed data at the surface, and the misfits for most regions of North China are within the uncertainty of the heat flow measurements. Three main characteristics can be observed from the distribution of temperature: (1) lithospheric temperature at shallow depth is in consistent with the tectonic settings. At depth shallower than 170 km, temperature under the active tectonic eastern part of North China is higher than that in the stable cratonic regions in west. The regions with high mantle temperature include the Hehuai Basin, the Bohai Bay Basin, the boundary between North China Plain and the central North China; hotter lithosphere can also be found at the northern margin of Ordos Plateau, including the Yinchuan-Hetao Rift Zone and the Yinshan Orogen. (2) The lithospheric thickness in the regions with warmer lithosphere is about 80 -100 km thick, which is relatively thinner than the stable areas. The lowest temperature is located under the Ordos Plateau in western North China, which is about 200 to 400°C lower than that in the eastern North China. The lithosphere in the Ordos block is also the thickest in the north China, with thickness ranges 140-150 km on average and about 160 km in the thickest areas; (3) At the depth between 170 and 280 km, the distribution pattern of the thermal structure is almost reverse

  12. S-wave Anisotropy and Crack Distribution at the Coso Geothermal Field, California

    NASA Astrophysics Data System (ADS)

    Vlahovic, G.; Elkibbi, M.; Rial, J. A.

    2001-05-01

    The Coso geothermal area is located along the eastern front of Sierra Nevada, in the southwestern Basin and Range Province. Seismic activity averaging more than 20 microearthquakes per day is the result of both regional tectonics and geothermal production activity [Malin, 1994]. Microseismicity is monitored by the Coso Digital Downhole Seismic Network (CDDSN) recording at 2 ms sampling rate. Continuous operation of the CDDSN since 1990 created a data set of exceptional richness and continuity. We used data accumulated from January 1999 through June 2000 for the study of S wave anisotropy and crack distribution. Understanding the faults and associated fracture system in Coso is fundamental for efficient long-term energy extraction and micro-tectonic models of the area. Strike of cracks in the shear-wave window of each station was determined by plotting rose diagrams of the fast shear-wave polarization directions. Each rose diagram has a clear dominant polarization direction, interpreted as the direction of the local fracture system. Three dominant strike groups were observed: 0 - 20 NE, 40 - 60 NE and 20 - 40 NW. These results are consistent with subsurface crack directions determined by Lou and Rial [1997], and with photographically and magnetically mapped alignments on the surface [Moore and Erskine, 1990], as well as with deep borehole observations. Four stations centered in the geothermal production area were selected for detailed study of variation of arrival time delays between fast and slow shear-waves and changes of polarization of leading shear-wave with time. Preliminary results suggest that for one station in the northeast end of the geothermal field, there is an increase in number of secondary fractures with strike from 10 NW to 30 NE in the data from January to June of 2000, relative to data from January to June of 1999. Statistical significance and reasons for such a change will be further studied, although it is interesting to note that this station

  13. Anomalously low amplitude of S waves produced by the 3D structures in the lower mantle

    NASA Astrophysics Data System (ADS)

    To, Akiko; Capdeville, Yann; Romanowicz, Barbara

    2016-07-01

    mostly overlaps with the northern part of the Pacific large low shear velocity province (LLSVP) revealed in tomographic models. Although the very low amplitudes observed at a distance of about 95° remain unexplained, our results indicate that the boundary of the Pacific LLSVP is sharp, and the amplitude of S waves at these large distances is lowered by strong vertical and/or lateral deflection at the boundary toward the interior of the low velocity province.

  14. Comparison of P- and S-wave velocity profiles obtained from surface seismic refraction/reflection and downhole data

    USGS Publications Warehouse

    Williams, R.A.; Stephenson, W.J.; Odum, J.K.

    2003-01-01

    High-resolution seismic-reflection/refraction data were acquired on the ground surface at six locations to compare with near-surface seismic-velocity downhole measurements. Measurement sites were in Seattle, WA, the San Francisco Bay Area, CA, and the San Fernando Valley, CA. We quantitatively compared the data in terms of the average shear-wave velocity to 30-m depth (Vs30), and by the ratio of the relative site amplification produced by the velocity profiles of each data type over a specified set of quarter-wavelength frequencies. In terms of Vs30, similar values were determined from the two methods. There is <15% difference at four of the six sites. The Vs30 values at the other two sites differ by 21% and 48%. The relative site amplification factors differ generally by less than 10% for both P- and S-wave velocities. We also found that S-wave reflections and first-arrival phase delays are essential for identifying velocity inversions. The results suggest that seismic reflection/refraction data are a fast, non-invasive, and less expensive alternative to downhole data for determining Vs30. In addition, we emphasize that some P- and S-wave reflection travel times can directly indicate the frequencies of potentially damaging earthquake site resonances. A strong correlation between the simple S-wave first-arrival travel time/apparent velocity on the ground surface at 100 m offset from the seismic source and the Vs30 value for that site is an additional unique feature of the reflection/refraction data that could greatly simplify Vs30 determinations. ?? 2003 Elsevier Science B.V. All rights reserved.

  15. Estimation of shallow S-wave velocity structure in the Puli basin, Taiwan, using array measurements of microtremors

    NASA Astrophysics Data System (ADS)

    Wu, Cheng-Feng; Huang, Huey-Chu

    2012-05-01

    The September 21, 1999, Chi-Chi earthquake induced strong shaking, resulting in severe damage in the Puli area. According to Huang and Tarng (2005), the collapse of many structures during the earthquake was very closely related to site effects. Shallow shear-wave velocities are widely used for earthquake ground-motion site characterization. Thus, we investigate S-wave velocity structures for the Puli area by performing microtremor array measurements at 16 sites. Dispersion curves at these sites are calculated using the F-K method (Capon, 1969) for the vertical component; S-wave velocity structures for the Puli area are then estimated by surface wave inversion (Herrmann, 1991). If the S-wave velocity of the bedrock is assumed to be 2000 m/s, the depths of the Quaternary sediments in the Puli area are between 300 m (FAL, PIP) and 870 m (DAH). Moreover, there are 3˜6 distinct interfaces in the shallow velocity structure (0˜1000 m). The depth of the bedrock gradually increases from the edge (SIN, PIP) to the center (PUL, DAH) of the basin and the thickest Quaternary sediments appear near Heng-Chih-Cheng (DAH).

  16. Q-values for P and S waves in Southern Sinai and Southern Gulf of Suez Region, Egypt

    NASA Astrophysics Data System (ADS)

    Mohamed, Gad-Elkareem A.

    2014-05-01

    The quality factor Q has been estimated using spectral amplitudes of P and S waves from earthquakes recorded by the seismic network of the Egyptian National Seismological Network (ENSN) in southern Sinai and southern Gulf of Suez region. The earthquakes recorded at nine stations - DHA, NUB, TR1, TR2, KAT, SH2, GRB, HRG and SFG have been used in this study. The spectral amplitude ratios have been calculated between 2 - 20 Hz and single station spectral ratio method has been applied for this purpose. The results show that the quality factors for both P and S waves (Qp and Qs) increase as a function of frequency according to law the Q = Q0fn. By averaging the estimated Q- Value obtained at all stations we calculated the average attenuation laws: Qp = (13.15± 0.76) f0.95± 0.19 and Qs = (20.05± 0.79) f1.03±0.04 for P and S waves respectively. These relations are useful for the estimation of source parameters of earthquakes and simulation of earthquake strong ground motions. The QS /QP ratio for KAT station is less than 1 at lower frequencies, whereas at HRG and SH2 stations QS /QP ratio is are greater than 1.

  17. S-wave velocity and Poisson's ratio model in Southern Chile along a transect at 38°15'S from active and passive TIPTEQ data

    NASA Astrophysics Data System (ADS)

    Ramos, Catalina; Mechie, James

    2015-04-01

    Using active and passive seismology data from project TIPTEQ (from The Incoming Plate to mega-Thrust EarthQuake processes) we derive a shear (S) wave velocity and a Poisson's ratio (σ) model across the Chilean convergent margin along 38°15'S, where the Mw 9.5 Valdivia earthquake is believed to have occurred. The obtained S-wave velocity model consists of three different tomographic images that were merged together. In the upper part (0 - 5 km depth), controlled source data from explosions were used to obtain a S-wave travel-time tomography. In the middle part (5 - 20 km depth) a dispersion analysis and then a noise tomography were carried out in two different ways: one used the dispersion curves to obtain a 3D S-wave velocity model in one step and the other used the dispersion curves to obtain surface-wave velocity tomographic images for different periods and then used the surface-wave velocity values every 10 km along the profile to obtain 1D S-wave velocity profiles every 10 km that were then interpolated to obtain a 2D S-wave tomography. Both methods produce similar S-wave travel-times. In the lower part (20 - 75 km depth, depending on the longitude) an already existent S-wave velocity model from local earthquake tomography was merged with the other two sections. The final S-wave velocity model and already existent compressional (P) wave velocity models along the same transect allowed us to obtain a Poisson's ratio model. The results show that the velocities and Poisson's ratios in this part of the Chilean convergent margin can all be explained in terms of normal rock types. There is no requirement to call on the existence of significant amounts of present-day fluids in the continental lithosphere above the plate interface in this part of the Chilean convergent margin, to explain the derived velocities and Poisson's ratios.

  18. Determination of the s-Wave Scattering Length and the C{sub 6} van der Waals Coefficient of {sup 174}Yb via Photoassociation Spectroscopy

    SciTech Connect

    Enomoto, K.; Kitagawa, M.; Kasa, K.; Tojo, S.; Takahashi, Y.

    2007-05-18

    We report photoassociation spectroscopy of {sup 174}Yb for the {sup 1}S{sub 0}-{sup 1}P{sub 1} transition at 1 {mu}K, where only the s-wave scattering state contributes to the spectra. The wave function of the s-wave scattering state is obtained from the photoassociation efficiency, and we determine that the C{sub 6} potential coefficient is 2300{+-}250 a.u. and the s-wave scattering length is 5.53{+-}0.11 nm. Based on these parameters, we discuss the scattering properties of s- and d-wave states.

  19. Determination of the s-wave scattering length and the C6 van der Waals coefficient of 174Yb via photoassociation spectroscopy.

    PubMed

    Enomoto, K; Kitagawa, M; Kasa, K; Tojo, S; Takahashi, Y

    2007-05-18

    We report photoassociation spectroscopy of 174Yb for the 1S(0)-1P1 transition at 1 microK, where only the s-wave scattering state contributes to the spectra. The wave function of the s-wave scattering state is obtained from the photoassociation efficiency, and we determine that the C6 potential coefficient is 2300+/-250 a.u. and the s-wave scattering length is 5.53+/-0.11 nm. Based on these parameters, we discuss the scattering properties of s- and d-wave states. PMID:17677695

  20. High-resolution 3-D S-wave Tomography of upper crust structures in Yilan Plain from Ambient Seismic Noise

    NASA Astrophysics Data System (ADS)

    Chen, Kai-Xun; Chen, Po-Fei; Liang, Wen-Tzong; Chen, Li-Wei; Gung, YuanCheng

    2015-04-01

    The Yilan Plain (YP) in NE Taiwan locates on the western YP of the Okinawa Trough and displays high geothermal gradients with abundant hot springs, likely resulting from magmatism associated with the back-arc spreading as attested by the offshore volcanic island (Kueishantao). YP features NS distinctive characteristics that the South YP exhibits thin top sedimentary layer, high on-land seismicity and significant SE movements, relative those of the northern counterpart. A dense network (~2.5 km station interval) of 89 Texan instruments was deployed in Aug. 2014, covering most of the YP and its vicinity. The ray path coverage density of each 0.015 degree cells are greater than 150 km that could provide the robustness assessment of tomographic results. We analyze ambient noise signals to invert a high-resolution 3D S-wave model for shallow velocity structures in and around YP. The aim is to investigate the velocity anomalies corresponding to geothermal resources and the NS geological distinctions aforementioned. We apply the Welch's method to generate empirical Rayleigh wave Green's functions between two stations records of continuous vertical components. The group velocities of thus derived functions are then obtained by the multiple-filter analysis technique measured at the frequency range between 0.25 and 1 Hz. Finally, we implement a wavelet-based multi-scale parameterization technique to construct 3D model of S-wave velocity. Our first month results exhibit low velocity in the plain, corresponding existing sediments, those of whole YP show low velocity offshore YP and those of high-resolution south YP reveal stark velocity contrast across the Sanshin fault. Key words: ambient seismic noises, Welch's method, S-wave, Yilan Plain

  1. 2.5D S-wave velocity model of the TESZ area in northern Poland from receiver function analysis

    NASA Astrophysics Data System (ADS)

    Wilde-Piorko, Monika; Polkowski, Marcin; Grad, Marek

    2016-04-01

    Receiver function (RF) locally provides the signature of sharp seismic discontinuities and information about the shear wave (S-wave) velocity distribution beneath the seismic station. The data recorded by "13 BB Star" broadband seismic stations (Grad et al., 2015) and by few PASSEQ broadband seismic stations (Wilde-Piórko et al., 2008) are analysed to investigate the crustal and upper mantle structure in the Trans-European Suture Zone (TESZ) in northern Poland. The TESZ is one of the most prominent suture zones in Europe separating the young Palaeozoic platform from the much older Precambrian East European craton. Compilation of over thirty deep seismic refraction and wide angle reflection profiles, vertical seismic profiling in over one hundred thousand boreholes and magnetic, gravity, magnetotelluric and thermal methods allowed for creation a high-resolution 3D P-wave velocity model down to 60 km depth in the area of Poland (Grad et al. 2016). On the other hand the receiver function methods give an opportunity for creation the S-wave velocity model. Modified ray-tracing method (Langston, 1977) are used to calculate the response of the structure with dipping interfaces to the incoming plane wave with fixed slowness and back-azimuth. 3D P-wave velocity model are interpolated to 2.5D P-wave velocity model beneath each seismic station and synthetic back-azimuthal sections of receiver function are calculated for different Vp/Vs ratio. Densities are calculated with combined formulas of Berteussen (1977) and Gardner et al. (1974). Next, the synthetic back-azimuthal sections of RF are compared with observed back-azimuthal sections of RF for "13 BB Star" and PASSEQ seismic stations to find the best 2.5D S-wave models down to 60 km depth. National Science Centre Poland provided financial support for this work by NCN grant DEC-2011/02/A/ST10/00284.

  2. S-Wave Velocity Structure of the Taiwan Chelungpu Fault Drilling Project (TCDP) Site Using Microtremor Array Measurements

    NASA Astrophysics Data System (ADS)

    Wu, Cheng-Feng; Huang, Huey-Chu

    2015-10-01

    The Taiwan Chelungpu Fault Drilling Project (TCDP) drilled a 2-km-deep hole 2.4 km east of the surface rupture of the 1999 Chi-Chi earthquake ( M w 7.6), near the town of Dakeng. Geophysical well logs at the TCDP site were run over depths ranging from 500 to 1,900 m to obtain the physical properties of the fault zones and adjacent damage zones. These data provide good reference material for examining the validity of velocity structures using microtremor array measurement; therefore, we conduct array measurements for a total of four arrays at two sites near the TCDP drilling sites. The phase velocities at frequencies of 0.2-5 Hz are calculated using the frequency-wavenumber ( f- k) spectrum method. Then the S-wave velocity structures are estimated by employing surface wave inversion techniques. The S-wave velocity from the differential inversion technique gradually increases from 1.52 to 2.22 km/s at depths between 585 and 1,710 m. This result is similar to those from the velocity logs, which range from 1.4 km/s at a depth of 597 m to 2.98 km/s at a depth of 1,705 m. The stochastic inversion results are similar to those from the seismic reflection methods and the lithostratigraphy of TCDP-A borehole, comparatively. These results show that microtremor array measurement provides a good tool for estimating deep S-wave velocity structure.

  3. Near-surface S-wave velocity measured with six-degree-of-freedom seismic sensor Rotaphone

    NASA Astrophysics Data System (ADS)

    Malek, Jiri; Brokesova, Johana

    2015-04-01

    An essential parameter in seismic engineering is the near-surface S-wave velocity. Rotaphone, a six-degree-of-freedom seismic sensor can be used with advantage to retrieve it from collocated rotational and translational measurements. Rotaphone consists of highly sensitive geophones connected to a conjoint datalogger. The geophones are mounted in parallel pairs to a rigid (metal) ground-based frame. The instrument is designed to measure short-period translational ground motion (velocity) and, in addition, differential motion between the paired geophones. The records of those differential motions are used to obtain rotational components. In-situ calibration of individual geophones is performed simultaneously with each measurement, which enables to reach high sensitivity and accuracy of rotational measurements. In our method we utilize seismic waves produced by anthropogenic source - a generator of S waves and rotational ground motions. The generator contains a fixed part (anchored to the ground), a revolving part and a braking mechanism for immediate braking of the rotational part, in which rotational seismic motions are generated by immediately stopping the revolving part, whereby energy is transmitted into the rock massive. The generator produces repeatedly identical source pulses. Due to identity of the source pulses, we can suppress noise by means of stacking data from many generator actions and thus increase the depth range and resolution. The phase velocity retrieval is based on matching relevant acceleration and rotation rate components. Thanks to a near-source distance and high-frequency content of the source pulses, well-known equations for plane-wave approximation must be replaced by more adequate equations relating the individual rotation rate components to the translational ones. These equations are derived under an assumption of spherical wave. The resulting S-wave phase velocity is compared to the value obtained by standard profile measurements. The

  4. P and S Waves Traversing Beneath Western Japan and the Shape of the Subducting Philippine Sea Plate

    NASA Astrophysics Data System (ADS)

    Kuge, K.; Fukuda, T.

    2011-12-01

    We show the characteristics of P and S waves traversing beneath western Japan, which can provide constraints on the shape of the subducting Philippine Sea plate. The subduction of the Philippine Sea plate causes megathrust earthquakes along the Nankai trough in western Japan. The complicated shape of the subducting plate can affect the spatial variation of the plate coupling as well as the recurrence of great interplate earthquakes. For slab earthquakes at depths of about 45 km in northwestern Shikoku, we observe two arrivals of P wave at the NIED Hi-net stations in the azimuth range from the north to the east. The apparent velocities are about 8 and 6.7 km/s, corresponding to P velocities in the mantle and crust, respectively. Dominant S waves propagate by apparent velocity of about 3.8 km/s, being S velocity in the crust. These observations are in agreement with those of Oda et al. (1990) and Ohkura (2000) using a smaller number of local stations. The P and S waves propagating at the slow apparent velocities can be modeled by horizontally layered structure if the earthquakes are located within a low-velocity layer spanning the stations. The thick low-velocity layer can be a stack of the continental crust of the Eurasian plate and the oceanic crust of the Philippine Sea plate subducting nearly subhorizontally (Oda et al., 1990; Ohkura, 2000). The P and S waves with the slow apparent velocities are observable at distances up to about 300 km. On the other hand, they are not observed or observable only at small distances in the western side of the epicenters. The spatial characteristics can be used to constrain the geometry of the low-velocity layer associated with the shape of the oceanic crust of the Philippine Sea plate. We observe two arrivals of P wave in the eastern side of the Kii Peninsula for slab earthquakes beneath Shikoku. Both apparent velocities are in a range of P velocity in the mantle. There appear two ray paths of P wave propagating in the mantle

  5. p{sub x}+ip{sub y} Superfluid from s-Wave Interactions of Fermionic Cold Atoms

    SciTech Connect

    Zhang Chuanwei; Tewari, Sumanta; Lutchyn, Roman M.; Das Sarma, S.

    2008-10-17

    Two-dimensional (p{sub x}+ip{sub y}) superfluids or superconductors offer a playground for studying intriguing physics such as quantum teleportation, non-Abelian statistics, and topological quantum computation. Creating such a superfluid in cold fermionic atom optical traps using p-wave Feshbach resonance is turning out to be challenging. Here we propose a method to create a p{sub x}+ip{sub y} superfluid directly from an s-wave interaction making use of a topological Berry phase, which can be artificially generated. We discuss ways to detect the spontaneous Hall mass current, which acts as a diagnostic for the chiral p-wave superfluid.

  6. The Study on S-Wave Velocity Structure of Upper Crust in Three Gorges Region of Yangtze River

    NASA Astrophysics Data System (ADS)

    Li, X.; Zhu, P.; Zhou, Q.

    2014-12-01

    The profile of S-wave velocity structure along Badong-Maoping-Tumen is presented using the ambient noise data observed at 10 stations from mobile broadband seismic array which is located at Three Gorges Region. All of available vertical component time series during April and May,2011 have been cross-correlated to estimate the empirical Green functions. Group velocity dispersion curves were measured by applying multiple filtering technique. Using these dispersion curves,we obtain high resolution pure-path dispersions at 0.5-10 second periods. The S-wave velocity structure,which was reconstructed by inverting the pure-path dispersions,reveals the velocity variations of upper crust at Three Gorges Region. Main conclusions are as follows:(1)The velocity variations in the study region have a close relationship with the geological structure and the velocity profile suggests a anticline unit which core area is Huangling block;(2)The relative fast velocity variations beneath Jiuwanxi and its surrounding areas may correspond to the geological structure and earthquake activity there;(3) The high velocity of the upper crustal in Sandouping indicates that the Reservoir Dam of Three Gorges is located at a tectonic stable region.

  7. T-waves excited by S-waves and oscillated within the ocean above the Southeastern Taiwan Forearc

    NASA Astrophysics Data System (ADS)

    Lin, Cheng-Horng

    The generation processes of T-waves were investigated from seismograms produced by a local intermediate-depth earthquake and recorded at one short-period station in Taiwan. The first group of T-phases arrived 44 seconds after the S-phases, while the following 2 groups consistently had the same travel-time difference of about 88 seconds each. Analyses of the ray paths and travel-times of these phases show that the T-waves were converted from the S-waves and oscillated within the ocean above the forearc in the southeastern Taiwan area. Further comparisons of these results with those of previous studies suggest that the generation of T-waves is probably dependent on the incidence angles of the seismic waves. The T-waves were converted from S-waves when the incidence angles of the seismic waves were near vertical, whereas they were generated from P-waves when those angles were near horizontal.

  8. Global upper-mantle tomography with the automated multimode inversion of surface and S-wave forms

    NASA Astrophysics Data System (ADS)

    Lebedev, Sergei; van der Hilst, Rob D.

    2008-05-01

    We apply the Automated Multimode Inversion of surface and S-wave forms to a large global data set, verify the accuracy of the method and assumptions behind it, and compute an Sv-velocity model of the upper mantle (crust-660 km). The model is constrained with ~51000 seismograms recorded at 368 permanent and temporary broadband seismic stations. Structure of the mantle and crust is constrained by waveform information both from the fundamental-mode Rayleigh waves (periods from 20 to 400 s) and from S and multiple S waves (higher modes). In order to enhance the validity of the path-average approximation, we implement the automated inversion of surface- and S-wave forms with a three-dimensional (3-D) reference model. Linear equations obtained from the processing of all the seismograms of the data set are inverted for seismic velocity variations also relative to a 3-D reference, in this study composed of a 3-D model of the crust and a one-dimensional (1-D), global-average depth profile in the mantle below. Waveform information is related to shear- and compressional-velocity structure within approximate waveform sensitivity areas. We use two global triangular grids of knots with approximately equal interknot spacing within each: a finely spaced grid for integration over sensitivity areas and a rougher-spaced one for the model parametrization. For the tomographic inversion we use LSQR with horizontal and vertical smoothing and norm damping. We invert for isotropic variations in S- and P-wave velocities but also allow for S-wave azimuthal anisotropy-in order to minimize errors due to possible mapping of anisotropy into isotropic heterogeneity. The lateral resolution of the resulting isotropic upper-mantle images is a few hundred kilometres, varying with data sampling. We validate the imaging technique with a `spectral-element' resolution test: inverting a published global synthetic data set computed with the spectral-element method using a laterally heterogeneous mantle

  9. s-wave scattering for deep potentials with attractive tails falling off faster than -1/r2

    NASA Astrophysics Data System (ADS)

    Müller, Tim-Oliver; Kaiser, Alexander; Friedrich, Harald

    2011-09-01

    For potentials with attractive tails, as occur in typical atomic interactions, we present a simple formula for the s-wave phase shift δ0. It exposes a universal dependence of δ0(E) on the potential tail and the influence of effects specific to a given potential, which enter via the scattering length a, or equivalently, the noninteger part Δth of the threshold quantum number nth. The formula accurately reproduces δ0(E) from threshold up to the semiclassical regime, far beyond the validity of the effective-range expansion. We derive the tail functions occurring in the formula for δ0(E) and demonstrate the validity of the formula for attractive potential tails proportional to 1/r6 or to 1/r4, and also for a mixed potential tail consisting of a 1/r4 term together with a non-negligible 1/r6 contribution.

  10. Measurement of the p to s Wave Branching Ratio of {sup 187}Re {beta} Decay from Beta Environmental Fine Structure

    SciTech Connect

    Arnaboldi, C.; Brofferio, C.; Capelli, S.; Capozzi, F.; Cremonesi, O.; Fiorini, E.; Nucciotti, A.; Pavan, M.; Pessina, G.; Pirro, S.; Previtali, E.; Sisti, M.; Benedek, G.; Filipponi, A.; Giuliani, A.; Pedretti, M.; Monfardini, A.

    2006-02-03

    The mixed occurrence of s-wave and p-wave contributions in a first forbidden unique Gamow-Teller {beta} decay has been investigated for the first time by measuring the beta environmental fine structure (BEFS) in a {sup 187}Re crystalline compound. The experiment has been carried out with an array of eight AgReO{sub 4} thermal detectors operating at a temperature of {approx}100 mK. A fit of the observed BEFS spectrum indicates the p-wave electron emission as the dominant channel. The complete understanding of the BEFS distortion of the {sup 187}Re {beta} decay spectrum is crucial for future experiments aiming at the precise calorimetric measurement of the antineutrino mass.

  11. Characterization of U.S. Wave Energy Converter (WEC) Test Sites: A Catalogue of Met-Ocean Data.

    SciTech Connect

    Dallman, Ann Renee; Neary, Vincent Sinclair

    2014-10-01

    This report presents met - ocean data and wave energy characteristics at three U.S. wave energy converter (WEC) test and potential deployment sites . Its purpose is to enable the compari son of wave resource characteristics among sites as well as the select io n of test sites that are most suitable for a developer's device and that best meet their testing needs and objectives . It also provides essential inputs for the design of WEC test devices and planning WEC tests, including the planning of deployment and op eration s and maintenance. For each site, this report catalogues wave statistics recommended in the (draft) International Electrotechnical Commission Technical Specification (IEC 62600 - 101 TS) on Wave Energy Characterization, as well as the frequency of oc currence of weather windows and extreme sea states, and statistics on wind and ocean currents. It also provides useful information on test site infrastructure and services .

  12. The Effect of Crack Orientation on the Nonlinear Interaction of a P-wave with an S-wave

    DOE PAGESBeta

    TenCate, J. A.; Malcolm, A. E.; Feng, X.; Fehler, M. C.

    2016-06-06

    Cracks, joints, fluids, and other pore-scale structures have long been hypothesized to be the cause of the large elastic nonlinearity observed in rocks. It is difficult to definitively say which pore-scale features are most important, however, because of the difficulty in isolating the source of the nonlinear interaction. In this work, we focus on the influence of cracks on the recorded nonlinear signal and in particular on how the orientation of microcracks changes the strength of the nonlinear interaction. We do this by studying the effect of orientation on the measurements in a rock with anisotropy correlated with the presencemore » and alignment of microcracks. We measure the nonlinear response via the traveltime delay induced in a low-amplitude P wave probe by a high-amplitude S wave pump. We find evidence that crack orientation has a significant effect on the nonlinear signal.« less

  13. Measurement of the imaginary part of the I = 1 N-barN S-wave scattering length

    SciTech Connect

    Mutchler, G.S.; Clement, J.; Kruk, J.; Moss, R.; Hungerford, E.; Kishimoto, T.; Mayes, B.; Pinsky, L.; Tang, L.; Xue, Y.; and others

    1988-08-01

    The survival time spectrum of slow antineutrons produced in a liquid-hydrogen target has been measured. From these data the imaginary part of the I = 1 spin-averaged S-wave antineutron proton scattering length has been deduced to be Ima/sub 1/ = -0.83 +- 0.07 fm. The result lies within the range of values calculated from current potential models. In addition, by combining a/sub 1/ with the antiproton-proton scattering length deduced from antiprotonic atoms, the imaginary part of the I = 0 spin-averaged N-barN scattering length was calculated to be Ima/sub 0/ = -1.07 +- 0.16 fm.

  14. The effect of crack orientation on the nonlinear interaction of a P wave with an S wave

    NASA Astrophysics Data System (ADS)

    TenCate, J. A.; Malcolm, A. E.; Feng, X.; Fehler, M. C.

    2016-06-01

    Cracks, joints, fluids, and other pore-scale structures have long been hypothesized to be the cause of the large elastic nonlinearity observed in rocks. It is difficult to definitively say which pore-scale features are most important, however, because of the difficulty in isolating the source of the nonlinear interaction. In this work, we focus on the influence of cracks on the recorded nonlinear signal and in particular on how the orientation of microcracks changes the strength of the nonlinear interaction. We do this by studying the effect of orientation on the measurements in a rock with anisotropy correlated with the presence and alignment of microcracks. We measure the nonlinear response via the traveltime delay induced in a low-amplitude P wave probe by a high-amplitude S wave pump. We find evidence that crack orientation has a significant effect on the nonlinear signal.

  15. Theoretical study of large proximity-induced s -wave-like pairing from a d -wave superconductor

    NASA Astrophysics Data System (ADS)

    Li, Wan-Ju; Chao, Sung-Po; Lee, Ting-Kuo

    2016-01-01

    We use the proximity effect to generate effective topological superconductors by placing metals with strong spin-orbit coupling in contact with a superconductor, aiming to produce Majorana zero modes useful for topologically protected quantum computation. In recent experiments, several quintuple layers of Bi2Se3 were epitaxially grown on the high-Tc material Bi2Sr2CaCu2O8+δ , and conflicting experimental results were reported. We use the standard mean-field approach to study this heterostructure and find it is unlikely to have a large proximity-induced superconducting gap. Despite the seemingly correct temperature dependence, the s -wave gap claimed to be observed may not be purely superconducting in origin. Future work on the proximity-induced bulk superconducting gap and the interfacial band structure should shed light on this issue.

  16. The leading twist light-cone distribution amplitudes for the S-wave and P-wave Bc mesons

    NASA Astrophysics Data System (ADS)

    Xu, Ji; Yang, Deshan

    2016-07-01

    The light-cone distribution amplitudes (LCDAs) serve as important nonperturbative inputs for the study of hard exclusive processes. In this paper, we calculate ten LCDAs at twist-2 for the S-wave and P-wave B c mesons up to the next-to-leading order (NLO) of the strong coupling α s and leading order of the velocity expansion. Each one of these ten LCDAs is expressed as a product of a perturbatively calculable distribution and a universal NRQCD matrix-element. By use of the spin symmetry, only two NRQCD matrix-elements will be involved. The reduction of the number of non-perturbative inputs will improve the predictive power of collinear factorization.

  17. Upper-mantle seismic structure beneath SE and Central Brazil from P- and S-wave regional traveltime tomography

    NASA Astrophysics Data System (ADS)

    Rocha, Marcelo Peres; Schimmel, Martin; Assumpção, Marcelo

    2011-01-01

    We present models for the upper-mantle velocity structure beneath SE and Central Brazil using independent tomographic inversions of P- and S-wave relative arrival-time residuals (including core phases) from teleseismic earthquakes. The events were recorded by a total of 92 stations deployed through different projects, institutions and time periods during the years 1992-2004. Our results show correlations with the main tectonic structures and reveal new anomalies not yet observed in previous works. All interpretations are based on robust anomalies, which appear in the different inversions for P- and S-waves. The resolution is variable through our study volume and has been analyzed through different theoretical test inversions. High-velocity anomalies are observed in the western portion of the São Francisco Craton, supporting the hypothesis that this Craton was part of a major Neoproterozoic plate (San Franciscan Plate). Low-velocity anomalies beneath the Tocantins Province (mainly fold belts between the Amazon and São Francisco Cratons) are interpreted as due to lithospheric thinning, which is consistent with the good correlation between intraplate seismicity and low-velocity anomalies in this region. Our results show that the basement of the Paraná Basin is formed by several blocks, separated by suture zones, according to model of Milani & Ramos. The slab of the Nazca Plate can be observed as a high-velocity anomaly beneath the Paraná Basin, between the depths of 700 and 1200 km. Further, we confirm the low-velocity anomaly in the NE area of the Paraná Basin which has been interpreted by VanDecar et al. as a fossil conduct of the Tristan da Cunha Plume related to the Paraná flood basalt eruptions during the opening of the South Atlantic.

  18. Gapped triplet p -wave superconductivity in strong spin-orbit-coupled semiconductor quantum wells in proximity to s -wave superconductor

    NASA Astrophysics Data System (ADS)

    Yu, T.; Wu, M. W.

    2016-05-01

    We show that gapped triplet superconductivity, i.e., a triplet superconductor with a triplet order parameter, can be realized in strong spin-orbit-coupled (100) quantum wells in proximity to an s -wave superconductor. It is revealed that in quantum wells with the singlet order parameter induced from the superconducting proximity effect, not only can the triplet pairings arise due to spin-orbit coupling, but the triplet order parameter can also be induced due to the repulsive effective electron-electron interaction, including the electron-electron Coulomb and electron-phonon interactions. This is a natural extension of the work of de Gennes, in which the repulsive-interaction-induced singlet order parameter arises in normal metal in proximity to an s -wave superconductor [Rev. Mod. Phys. 36, 225 (1964), 10.1103/RevModPhys.36.225]. Specifically, we derive the effective Bogoliubov-de Gennes equation, in which the self-energies due to the effective electron-electron interactions contribute to the singlet and triplet order parameters. It is further shown that for the singlet order parameter, it is efficiently suppressed due to this self-energy renormalization, whereas for the triplet order parameter it is the p -wave (px±i py ) one with the d vector parallel to the effective magnetic field due to the spin-orbit coupling. Finally, we perform a numerical calculation in InSb (100) quantum wells. Specifically, we reveal that the Coulomb interaction is much more important than the electron-phonon interaction at low temperature. Moreover, it is shown that with proper electron density, the minimum of the renormalized singlet and the maximum of the induced triplet order parameters are comparable, and hence they can be experimentally distinguished.

  19. Analytical study on holographic superfluid in AdS soliton background

    NASA Astrophysics Data System (ADS)

    Lai, Chuyu; Pan, Qiyuan; Jing, Jiliang; Wang, Yongjiu

    2016-06-01

    We analytically study the holographic superfluid phase transition in the AdS soliton background by using the variational method for the Sturm-Liouville eigenvalue problem. By investigating the holographic s-wave and p-wave superfluid models in the probe limit, we observe that the spatial component of the gauge field will hinder the phase transition. Moreover, we note that, different from the AdS black hole spacetime, in the AdS soliton background the holographic superfluid phase transition always belongs to the second order and the critical exponent of the system takes the mean-field value in both s-wave and p-wave models. Our analytical results are found to be in good agreement with the numerical findings.

  20. Implementation of an Automatic S-Wave Picker for Local Earthquake Tomography in South-Central Tibet

    NASA Astrophysics Data System (ADS)

    Riddle, E.; Nabelek, J.; Braunmiller, J.

    2012-12-01

    The HiCLIMB broadband seismic experiment (2002-2005) operated 233 stations along an 800 km long north-south line from the Himalayan foreland into the central Tibetan Plateau and in a 350x350 km sub-array within southern Tibet and central and eastern Nepal. From June 2004 to August 2005, over 22,500 local and regional seismic events were recorded throughout the south-central Tibetan Plateau based on automated arrival time picks. This dataset provides an opportunity to jointly invert for crust and upper mantle velocity structure along with earthquake locations using both P and S waves. The automated picks, however, were determined from vertical component data resulting in relatively few S picks of generally low quality. To increase the number of accurate S arrivals, we implemented an automatic S-wave picker, which uses signal attributes from three-component seismic data. The signal attributes used are rectilinearity, directivity relative to incoming P wave, ratio of transverse to overall energy and transverse amplitude. An S pick is declared when the combination of signal attributes reaches a noise dependent threshold. We used manual picks from events throughout south-central Tibet to adjust picking parameters and thresholds to optimize automatic S picks. For shallow events we found Sg can be picked reliably to the Sg/Sn crossover distance of approximately 3° while Sn arrivals are absent. Deep events beneath the southern Tibetan Plateau and the High Himalayas produce clear S arrivals that can be picked to about 5°-6° distance. Applying the S-picker to 584 larger (ML≥2.7), well-recorded events led to about 20,000 S picks; doubling the number of picks and significantly improving their accuracy. Compared to manual picks, the new automatic S picks show average differences of approximately 0.1 s from 0 to 100 km, 0.25 s from 100 to 200 km and 0.5 s from 200 to 250 km distance. This is significantly better than our previous S picks, which, from 100 to 250 km distance

  1. Validation of S-wave Velocity beneath the Ise Bay, Central Japan, Using Continuous Short-period Ambient Noise Data

    NASA Astrophysics Data System (ADS)

    Hayashida, T.; Yoshimi, M.; Horikawa, H.

    2014-12-01

    We have applied seismic interferometry to three-component ambient noise data recorded around the Ise bay area, central Japan, to validate published three-dimensional S-wave velocity models. For the bay area, detailed seismic velocity structure models have been constructed based on P-wave reflection surveys. There is no direct information on the S-wave velocities beneath the bay and the parameters are assigned by reference to those in a land area. We used one-year continuous data from 20 permanent stations of the NIED Hi-net (High-sensitivity seismograph network) to obtain stacked cross-correlation functions (CCFs) of ambient noise between station pairs that cross the bay. The CCFs were calculated, using one-hour data in the radial-radial (R-R), transverse-transverse (T-T) and vertical-vertical (Z-Z) directions for time lags of ±500s. Horizontal distances between the stations range form 15 km to 103 km. Although the Hi-net stations deploy seismometers with the natural period of 1 s, we found that the yearly stacked CCFs for selected 101 Hi-net station pairs are comparable with those derived from neighboring broadband seismic stations in the frequency range between 0.1 and 0.5 Hz, by deconvolving the instrument response. The CCFs shows clear Rayleigh waves from all directions in the R-R and Z-Z components, and clear Love waves in the T-T component with reasonable signal-to-noise ratios. The derived group velocities and waveforms of the wave trains are variable in the higher frequency range (> 0.2 Hz), indicating deep sedimentary basin beneath the bay. We compared obtained group velocities with theoretical ones to find systematic differences between the expected structure model from the CCFs and the published models in the northwest part of the bay, while the agreements are generally good for many other station pairs. This result indicates that the seismic interferometry technique provides valuable information for validation and improvement of a velocity structure

  2. High frequency measurement of P- and S-wave velocities on crystalline rock massif surface - methodology of measurement

    NASA Astrophysics Data System (ADS)

    Vilhelm, Jan; Slavík, Lubomír

    2014-05-01

    For the purpose of non-destructive monitoring of rock properties in the underground excavation it is possible to perform repeated high-accuracy P- and S-wave velocity measurements. This contribution deals with preliminary results gained during the preparation of micro-seismic long-term monitoring system. The field velocity measurements were made by pulse-transmission technique directly on the rock outcrop (granite) in Bedrichov gallery (northern Bohemia). The gallery at the experimental site was excavated using TBM (Tunnel Boring Machine) and it is used for drinking water supply, which is conveyed in a pipe. The stable measuring system and its automatic operation lead to the use of piezoceramic transducers both as a seismic source and as a receiver. The length of measuring base at gallery wall was from 0.5 to 3 meters. Different transducer coupling possibilities were tested namely with regard of repeatability of velocity determination. The arrangement of measuring system on the surface of the rock massif causes better sensitivity of S-transducers for P-wave measurement compared with the P-transducers. Similarly P-transducers were found more suitable for S-wave velocity determination then P-transducers. The frequency dependent attenuation of fresh rock massif results in limited frequency content of registered seismic signals. It was found that at the distance between the seismic source and receiver from 0.5 m the frequency components above 40 kHz are significantly attenuated. Therefore for the excitation of seismic wave 100 kHz transducers are most suitable. The limited frequency range should be also taken into account for the shape of electric impulse used for exciting of piezoceramic transducer. The spike pulse generates broad-band seismic signal, short in the time domain. However its energy after low-pass filtration in the rock is significantly lower than the energy of seismic signal generated by square wave pulse. Acknowledgments: This work was partially

  3. The ZH ratio method for long-period seismic data: inversion for S-wave velocity structure

    NASA Astrophysics Data System (ADS)

    Yano, Tomoko; Tanimoto, T.; Rivera, L.

    2009-10-01

    The particle motion of surface waves, in addition to phase and group velocities, can provide useful information for S-wave velocity structure in the crust and upper mantle. In this study, we applied a new method to retrieve velocity structure using the ZH ratio, the ratio between vertical and horizontal surface amplitudes of Rayleigh waves. Analysing data from the GEOSCOPE network, we measured the ZH ratios for frequencies between 0.004 and 0.05 Hz (period between 20 and 250s) and inverted them for S-wave velocity structure beneath each station. Our analysis showed that the resolving power of the ZH ratio is limited and final solutions display dependence on starting models; in particular, the depth of the Moho in the starting model is important in order to get reliable results. Thus, initial models for the inversion need to be carefully constructed. We chose PREM and CRUST2.0 in this study as a starting model for all but one station (ECH). The eigenvalue analysis of the least-squares problem that arises for each step of the iterative process shows a few dominant eigenvalues which explains the cause of the inversion's initial-model dependence. However, the ZH ratio is unique in having high sensitivity to near-surface structure and thus provides complementary information to phase and group velocities. Application of this method to GEOSCOPE data suggest that low velocity zones may exist beneath some stations near hotspots. Our tests with different starting models show that the models with low-velocity anomalies fit better to the ZH ratio data. Such low velocity zones are seen near Hawaii (station KIP), Crozet Island (CRZF) and Djibuti (ATD) but not near Reunion Island (RER). It is also found near Echery (ECH) which is in a geothermal area. However, this method has a tendency to produce spurious low velocity zones and resolution of the low velocity zones requires further careful study. We also performed simultaneous inversions for volumetric perturbation and

  4. Amplitude Anomalies of S Waves Caused by Low Shear Velocity Structures at the Base of the Mantle

    NASA Astrophysics Data System (ADS)

    To, A.; Capdeville, Y.; Romanowicz, B. A.

    2015-12-01

    Previous studies have shown that the direct S and Sdiff waveforms of earthquakes in Papua New Guinea region recorded by seismographs in Northern America are distorted due to sampling slow shear velocity anomalies at the base of the mantle. The emergence of postcursours to the S/Sdiff waves and the travel time anomalies have been reasonably explained by placing a ultra low velocity zone (ULVZ) in southwest of Hawaii. In this study, we focused on the amplitude anomalies of the S/Sdiff waveforms. The direct S phase show very low amplitude at stations in Southern California, at the distance and azimuth around 90 and 55 degrees from the earthquake. The amplitude is as low as 10% of the synthetic amplitude of a standard 1D model, especially at higher frequency range above 0.025 Hz. We first checked and confirmed that the anomalies are not due to errors in the focal mechanism, which is used to calculate the reference synthetic waveforms. Also we checked that the amplitude anomalies are unlikely to be caused by the structures near the earthquake or near the stations, by looking at the amplitude of the depth phases or waveforms of other earthquakes. We assumed that the anomalies are produced by the focusing and defocusing effect of sampling 3D heterogeneous at the base of the mantle, and searched for the causal structures. Full 3D synthetic waveforms are calculated down to 8 seconds for tens of structural models with slow anomalies of different size and velocity reduction placed on the core-mantle boundary (CMB). The result shows that existing tomographic models do not fully explain the observed amplitude anomalies. Stronger shear velocity anomalies are required. The previously proposed thin large ULVZ placed on the CMB southwest of Hawaii partly explains the observed amplitude reduction, even at the distance as short as 90 degrees from the earthquake. This result indicates the significance of finite frequency effect of the ULVZ structure to the S waves, since the ray

  5. Automated Measurement of P- and S-Wave Differential Times for Imaging Spatial Distributions of Vp/Vs Ratio, with Moving-Window Cross-Correlation Technique

    NASA Astrophysics Data System (ADS)

    Taira, T.; Kato, A.

    2013-12-01

    A high-resolution Vp/Vs ratio estimate is one of the key parameters to understand spatial variations of composition and physical state within the Earth. Lin and Shearer (2007, BSSA) recently developed a methodology to obtain local Vp/Vs ratios in individual similar earthquake clusters, based on P- and S-wave differential times. A waveform cross-correlation approach is typically employed to measure those differential times for pairs of seismograms from similar earthquakes clusters, at narrow time windows around the direct P and S waves. This approach effectively collects P- and S-wave differential times and however requires the robust P- and S-wave time windows that are extracted based on either manually or automatically picked P- and S-phases. We present another technique to estimate P- and S-wave differential times by exploiting temporal properties of delayed time as a function of elapsed time on the seismograms with a moving-window cross-correlation analysis (e.g., Snieder, 2002, Phys. Rev. E; Niu et al. 2003, Nature). Our approach is based on the principle that the delayed time for the direct S wave differs from that for the direct P wave. Two seismograms aligned by the direct P waves from a pair of similar earthquakes yield that delayed times become zero around the direct P wave. In contrast, delayed times obtained from time windows including the direct S wave have non-zero value. Our approach, in principle, is capable of measuring both P- and S-wave differential times from single-component seismograms. In an ideal case, the temporal evolution of delayed time becomes a step function with its discontinuity at the onset of the direct S wave. The offset in the resulting step function would be the S-wave differential time, relative to the P-wave differential time as the two waveforms are aligned by the direct P wave. We apply our moving-window cross-correlation technique to the two different data sets collected at: 1) the Wakayama district, Japan and 2) the Geysers

  6. Analytics for Education

    ERIC Educational Resources Information Center

    MacNeill, Sheila; Campbell, Lorna M.; Hawksey, Martin

    2014-01-01

    This article presents an overview of the development and use of analytics in the context of education. Using Buckingham Shum's three levels of analytics, the authors present a critical analysis of current developments in the domain of learning analytics, and contrast the potential value of analytics research and development with real world…

  7. Let's Talk... Analytics

    ERIC Educational Resources Information Center

    Oblinger, Diana G.

    2012-01-01

    Talk about analytics seems to be everywhere. Everyone is talking about analytics. Yet even with all the talk, many in higher education have questions about--and objections to--using analytics in colleges and universities. In this article, the author explores the use of analytics in, and all around, higher education. (Contains 1 note.)

  8. Stratigraphy of the Archean western Superior Province from P- and S-wave receiver functions: Further evidence for tectonic accretion?

    NASA Astrophysics Data System (ADS)

    Angus, D. A.; Kendall, J.-M.; Wilson, D. C.; White, D. J.; Sol, S.; Thomson, C. J.

    2009-12-01

    The Archean western Superior Province in Canada represents the nucleus of the North American continent whose origin has been speculated to be the result of widespread crustal accretion some 2.7 Ga ago. In this paper, crustal and upper-mantle seismic discontinuities beneath the western Superior Province of the Canadian shield are imaged with teleseismic P-to-S and S-to-P converted phases using the receiver function method. Three crustal discontinuities are observed: the Moho, ranging in depth between 38 and 47 km and dipping to the south; and two intra-crustal discontinuities having depths of approximately 15 and 30 km. The crustal discontinuities undulate laterally and often lose continuity, possibly indicating an imbricated structure and/or regions of velocity gradients. In the shallow lithosphere, a positive discontinuity is imaged at approximately 65 km depth and is consistent with earlier refraction and wide-angle reflection results. Additionally, two zones of negative receiver function amplitudes at 55 km depth are observed and are coincident with a region of anomalous tomographic low P- and S-wave velocities as well as a zone of high electrical conductivity. The images for the crust and shallow upper-mantle, when integrated with previous geophysical studies, are consistent with ideas of continental root formation due to imbrication of Archean subducted material and accretion of island arcs observed in surface geology.

  9. Relativistic corrections to the exclusive decays of C-even bottomonia into S-wave charmonium pairs

    SciTech Connect

    Sang Wenlong; Kim, U-Rae; Rashidin, Reyima; Lee, Jungil

    2011-10-01

    Within the nonrelativistic quantum chromodynamics (NRQCD) factorization formalism, we compute the relativistic corrections to the exclusive decays of bottomonia with even charge conjugation parity into S-wave charmonium pairs at leading order in the strong coupling constant. Relativistic corrections are resummed for a class of color-singlet contributions to all orders in the charm-quark velocity v{sub c} in the charmonium rest frame. Almost every process that we consider in this work has negative relativistic corrections ranging from -20 to -35%. Among the various processes, the relativistic corrections of the next-to-leading order in v{sub c} to the decay rate for {chi}{sub b2}{yields}{eta}{sub c}(mS)+{eta}{sub c}(nS) with m, n=1 or 2 are very large. In every case, the resummation of the relativistic corrections enhances the rate in comparison with the next-to-leading-order results. We compare our results with available predictions based on the NRQCD factorization formalism. The NRQCD predictions are significantly smaller than those based on the light-cone formalism by 1 or 2 orders of magnitude.

  10. Determination of the capture width of the 27. 7 keV s-wave resonance in /sup 56/Fe

    SciTech Connect

    Wisshak, K.; Kaeppeler, F.

    1980-09-01

    The capture width of the 27.7 keV s-wave resonance in /sup 56/Fe has been determined using a setup completely different from previous experiments. A pulsed 3 MV Van de Graaff accelerator and the /sup 7/Li(p,n) reaction served as a neutron source. Capture gamma rays were observed by a Moxon-Rae detector and gold was used as a standard. The samples were positioned at a flight path of only 7.6 - 8.0 cm. This allowed the use of very thin samples avoiding large multiple scattering corrections. Three metallic discs enriched in /sup 56/Fe were used with a thickness between 0.6 and 0.15 mm. Capture events in the detector due to resonance scattered neutrons were discriminated by time-of-flight. The result for the capture width is GAMMA/sub ..gamma../ = 0.99 with a statistical uncertainty of 1.3% and a systematic uncertainty of approx. 5%.

  11. Disorder effects in multiorbital s+/--wave superconductors: Implications for Zn-doped BaFe2As2 compounds

    NASA Astrophysics Data System (ADS)

    Chen, Hua; Tai, Yuan-Yen; Ting, C. S.; Graf, Matthias J.; Dai, Jianhui; Zhu, Jian-Xin

    2014-03-01

    Recent experiments on Zn-doped 122-type iron pnictides, Ba(Fe1 - x - yCoyZnx)2As2, are challenging our understanding of electron doping the 122s and the interplay between doping and impurity scattering. To resolve this enigma, we investigate the disorder effects of nonmagnetic Zn impurities on various properties of the system in the s+/--wave pairing state. The BdG is solved based on a minimal two-orbital model with an extended range of impurity concentrations. With increasing Zn concentration the density of states shows a gradual filling of the gap, revealing pair breaking effect. Both the averaged superconducting order parameter and superfluid density are dramatically suppressed towards the dirty limit, indicating the violation of the Anderson theorem and breakdown of the AG theory for impurity-averaged Green's functions. The superconductivity is fully suppressed close to the critical impurity concentration of nimp ~ 10 % , in agreement with recent experiments. NSF No.11274084, Z6110033, PHYS-1066293, 973 No. 2010CB923000, RAWF No. E-1146, LANL LDRD, CIN, U.S. DOE

  12. Strong enhancement of s -wave superconductivity near a quantum critical point of Ca3Ir4Sn13

    DOE PAGESBeta

    Biswas, P. K.; Guguchia, Z.; Khasanov, R.; Chinotti, M.; Li, L.; Wang, Kefeng; Petrovic, C.; Morenzoni, E.

    2015-11-11

    We repormore » t microscopic studies by muon spin rotation/relaxation as a function of pressure of the Ca3Ir4Sn13 and Sr3Ir4Sn13 system displaying superconductivity and a structural phase transition associated with the formation of a charge density wave (CDW). Our findings show a strong enhancement of the superfluid density and a dramatic increase of the pairing strength above a pressure of ≈ 1.6 GPa giving direct evidence of the presence of a quantum critical point separating a superconducting phase coexisting with CDW from a pure superconducting phase. The superconducting order parameter in both phases has the same s-wave symmetry. In spite of the conventional phonon-mediated BCS character of the weakly correlated (Ca1-xSrx)3Ir4Sn13 system the dependence of the effective superfluid density on the critical temperature puts this compound in the “Uemura” plot close to unconventional superconductors. This system exemplifies that conventional BCS superconductors in the presence of competing orders or multi-band structure can also display characteristics of unconventional superconductors.« less

  13. Estimation of shallow S-wave velocity structure and site response characteristics by microtremor array measurements in Tekirdag region, NW Turkey

    NASA Astrophysics Data System (ADS)

    Karagoz, Ozlem; Chimoto, Kosuke; Citak, Seckin; Ozel, Oguz; Yamanaka, Hiroaki; Hatayama, Ken

    2015-11-01

    In this study, we aimed to explore the S-wave velocity structure of shallow soils using microtremors in order to estimate site responses in Tekirdag and surrounding areas (NW Turkey). We collected microtremor array data at 44 sites in Tekirdag, Marmara Ereglisi, Corlu, and Muratlı. The phase velocities of Rayleigh waves were estimated from the microtremor data using a Spatial Autocorrelation method. Then, we applied a hybrid genetic simulated annealing algorithm to obtain a 1D S-wave velocity structure at each site. Comparison between the horizontal-to-vertical ratio of microtremors and computed ellipticities of the fundamental mode Rayleigh waves showed good agreement with validation models. The depth of the engineering bedrock changed from 20 to 50 m in the Tekirdag city center and along the coastline with a velocity range of 700-930 m/s, and it ranged between 10 and 65 m in Marmara Ereglisi. The average S-wave velocity of the engineering bedrock was 780 m/s in the region. We obtained average S-wave velocities in the upper 30 m to compare site amplifications. Empirical relationships between the AVs30, the site amplifications, and also average topographic slopes were established for use in future site effects microzonation studies in the region.

  14. Poisson's ratio model derived from P- and S-wave reflection seismic data at the CO2CRC Otway Project pilot site, Australia

    NASA Astrophysics Data System (ADS)

    Beilecke, Thies; Krawczyk, Charlotte M.; Tanner, David C.; Ziesch, Jennifer; Research Group Protect

    2014-05-01

    Compressional wave (P-wave) reflection seismic field measurements are a standard tool for subsurface exploration. 2-D seismic measurements are often used for overview measurements, but also as near-surface supplement to fill gaps that often exist in 3-D seismic data sets. Such supplementing 2-D measurements are typically simple with respect to field layout. This is an opportunity for the use of shear waves (S-waves). Within the last years, S-waves have become more and more important. One reason is that P- and S-waves are differently sensitive to fluids and pore fill so that the additional S-wave information can be used to enhance lithological studies. Another reason is that S-waves have the advantage of higher spatial resolution. Within the same signal bandwidth they typically have about half the wavelength of P-waves. In near-surface unconsolidated sediments they can even enhance the structural resolution by one order of magnitude. We make use of these capabilities within the PROTECT project. In addition to already existing 2-D P-wave data, we carried out a near surface 2-D S-wave field survey at the CO2CRC Otway Project pilot site, close to Warrnambool, Australia in November 2013. The combined analysis of P-wave and S-wave data is used to construct a Poisson's Ratio 2-D model down to roughly 600 m depth. The Poisson's ratio values along a 1 km long profile at the site are surprisingly high, ranging from 0.47 in the carbonate-dominated near surface to 0.4 at depth. In the literature, average lab measurements of 0.22 for unfissured carbonates and 0.37 for fissured examples have been reported. The high values that we found may indicate areas of rather unconsolidated or fractured material, or enhanced fluid contents, and will be subject of further studies. This work is integrated in a larger workflow towards prediction of CO2 leakage and monitoring strategies for subsurface storage in general. Acknowledgement: This work was sponsored in part by the Australian

  15. Correlation of 1- to 10-Hz earthquake resonances with surface measurements of S-wave reflections and refractions in the upper 50 m

    USGS Publications Warehouse

    Williams, R.A.; Stephenson, W.J.; Frankel, A.D.; Cranswick, E.; Meremonte, M.E.; Odum, J.K.

    2000-01-01

    Resonances observed in earthquake seismograms recorded in Seattle, Washington, the central United States and Sherman Oaks, California, are correlated with each site's respective near-surface seismic velocity profile and reflectivity determined from shallow seismic-reflection/refraction surveys. In all of these cases the resonance accounts for the highest amplitude shaking at the site above 1 Hz. These results show that imaging near-surface reflections from the ground surface can locate impedance structures that are important contributors to earthquake ground shaking. A high-amplitude S-wave reflection, recorded 250-m northeast and 300-m east of the Seattle Kingdome earthquake-recording station, with a two-way travel time of about 0.23 to 0.27 sec (about 18- to 22-m depth) marks the boundary between overlying alluvium (VS < 180 m/sec) and a higher velocity material (VS about 400 m/sec). This reflector probably causes a strong 2-Hz resonance that is observed in the earthquake data for the site near the Kingdome. In the central United States, S-wave reflections from a high-impedance boundary (an S-wave velocity increase from about 200 m/sec to 2000 m/sec) at about 40-m depth corresponds to a strong fundamental resonance at about 1.5 Hz. In Sherman Oaks, strong resonances at about 1.0 and 4 Hz are consistently observed on earthquake seismograms. A strong S-wave reflector at about 40-m depth may cause the 1.0 Hz resonance. The 4.0-Hz resonance is possibly explained by constructive interference between the first overtone of the 1.0-Hz resonance and a 3.25- to 3.9-Hz resonance calculated from an areally consistent impedance boundary at about 10-m depth as determined by S-wave refraction data.

  16. Geodynamic Environment by Satellite Geodesy, Seismic Attenuation and S-wave Splitting. Example from Vrancea Seismogenic Zone, SE Carpathians

    NASA Astrophysics Data System (ADS)

    Mocanu, Victor; Russo, Raymond; Ambrosius, Boudewijn

    2010-05-01

    In the Vrancea seismogenic zone (SE Carpathians), where very strong earthquakes (Mw > 7) are reported several times a century, the seismotectonics is very complex. It develops beneath the contact between the Moldavian East European Platform, the Scythian Platform, and the Moesian Platform, to the east and southeast, and terranes of the Transylvania Basin lying within the Carpathian arc. Several hypothesis have been considered by scientists in order to explain the clustered foci of crustal and intermediate events (as deep as 200 km). However, until now, there is no tectonic scenario which could explain all geological and geophysical observations. We try to integrate long-term permanent and campaign GPS outcomes with contributions from seismic attenuation and S-wave splitting results. GPS contributions mainly refer to determination of velocity vectors. 15 campaigns and seven permanent stations are being used in order to determine the detailed kinematics of an area characterized by very small velocities (1-2 mm/y), bringing the satellite technique to almost its limit. The results suggest a counterclockwise mantle flow around the Vrancea seismogenic zone, which is a high velocity body developed in an almost vertical position, developing deeper than 200 km. This results is also supported by seismic attenuation studies. We found that models like delamination and subduction could be supported by seismic attenuation studies in this zone. The delamination model implies strong upwelling and horizontal inflow of asthenosphere into the gap between the delaminating and remnant lithosphere. The other model implies downwelling and perhaps lateral-horizontal inflow along the slab detachment or tear. The models imply different distributions of density and rheological properties associated with the different lithosphere - asthenosphere structures. We use the ratio of spectral amplitudes of P and S waves from vertical and transverse seismograms to estimate the S to P ratio in the

  17. Crustal S-wave structure beneath Eastern Black Sea Region revealed by Rayleigh-wave group velocities

    NASA Astrophysics Data System (ADS)

    Çınar, Hakan; Alkan, Hamdi

    2016-01-01

    In this study, the crustal S-wave structure beneath the Eastern Black Sea Region (including the Eastern Black Sea Basin (EBSB) and Eastern Pontides (EP)) has been revealed using inversion of single-station, fundamental-mode Rayleigh-wave group velocities in the period range of 4-40 seconds. We used digital broadband recordings of 13 regional earthquakes that recently occurred in the easternmost EBSB recorded at stations of the Kandilli Observatory and Earthquake Research Institute (KOERI). The average group-velocity-dispersion curves were generated from 26 paths for the EBSB, and 16 paths for the EP, and they were inverted to determine the average 1-D shear-wave structure of the region. We have created a pseudo-section, roughly depicting the crustal structure of the region based on the group velocity inversion results of all station-earthquake paths. The thickness of the sedimentary layer reaches 12 km in the center of EBSB (Vs = 2.5-3.1 km/s) and decreases 4 km in the EP. There is a thin sedimentary layer in the EP (Vs = 2.7 km/s). A consolidated thin crust that exists in the EBSB possesses a high seismic velocity (Vs = 3.8 km/s). While a thin (∼26 km) and transitional crust exists beneath the EBSB, a thick (about 42 km) continental crust exists beneath the EP where the Conrad is clearly seen at about a 24 km depth. Thick continental crust in the EP region is clearly distinguished from a gradational velocity change (Vs = 3.4-3.8 km/s). The Moho dips approximately southwards, and the Vs velocity (4.25-4.15 km/s) beneath the Moho discontinuity decreases from the EBSB to the EP in the N-S direction. This may be an indication of a southward subduction.

  18. Multiple mantle upwellings beneath the Northern East-African Rift System from relative P- and S-wave traveltime tomography

    NASA Astrophysics Data System (ADS)

    Civiero, Chiara; Hammond, James; Goes, Saskia; Fishwick, Stewart; Ahmed, Abdulhakim; Ayele, Atalay; Doubre, Cecile; Goitom, Berhe; Keir, Derek; Kendall, Mike; Leroy, Sylvie; Ogubazghi, Ghebrebrhan; Rumpker, Georg; Stuart, Graham

    2015-04-01

    Mantle plumes have been invoked as the likely cause of East African Rift volcanism and extension. However, the nature of mantle upwelling is debated, with proposed configurations ranging from a single broad plume, the African Superplume, connected to the LLSVP beneath Southern Africa, to one or more distinct lower-mantle sources along the rift. We present a new relative travel-time tomography model that images detailed P- and S- wave velocities from P,S and SKS phases below the northern East-African, Red Sea and Gulf of Aden rift. Data comes from stations that cover the area from Tanzania to Saudi Arabia. The aperture of the integrated dataset allows us to image for the first time structures of ~100 km length scale down to depths of 900 km beneath this region. Our images provide evidence of at least two low-velocity structures with a diameter of ~200 km that continue through the transition zone and into the lower mantle: the first extends to at least 900 km beneath Afar, and a second reaching at least 750 km depth just west of the Main Ethiopian Rift, a region with off-rift volcanism. Taking into account seismic sensitivity to temperature and thermally controlled phase boundary topography, we interpret these features as multiple focused upwellings from below the transition zone with excess temperatures of 100±50 K. The scale of the upwellings is smaller than any of the previously proposed lower mantle plume sources. This suggests the ponding or flow of deep-plume material below the transition zone may be spawning smaller upper-mantle upwellings.

  19. Investigating the Crust and Upper Mantle of Antarctica based on S-Wave Receiver Functions Deployed in Ice Stations

    NASA Astrophysics Data System (ADS)

    Ramirez, C.; Nyblade, A.; Hansen, S. E.; Heeszel, D.; Wiens, D. A.; Anandakrishnan, S.; Aster, R. C.; Huerta, A. D.; Shore, P.; Wilson, T. J.

    2014-12-01

    The thick ice sheets that cover over 97% of the Antarctic continent make it difficult to study its geology. Seismic and other geophysical methods are the most effective ways to obtain information in this remote location. Using the classic receiver function technique, the P-to-S (Ps) conversion from the crust-mantle boundary is often masked by the ice multiples. Although removing these multiples by computational methods has been done, S-wave receiver functions (SRF) are a viable alternative and complementary method to estimate the crustal structure using S-to-P (Sp) conversions, which do not interfere with the ice multiples. In this project, we analyzed the data from the TAMSEIS, GAMSEIS and POLENET/ANET temporary seismic deployments. Sp arrival times are observed at ~5-6s in the Transantarctic Mountains and Wilkes Basin region, ~6-8s in the Gamburtsev Mountains and Vostok Higlands, and ~3-4s in the West Antarctic Rift System (WARS) and Marie Byrd Land Dome area. We used a grid search approach, combining the Sp time with Rayleigh wave phase velocities for 18 to 30 seconds, to estimate the Moho depth at each of the ice stations in the networks. The Moho depths obtained using these Sp times ranged from 28-45km, 37-59km and 16-35km respectively for the three general areas. We stacked the SRFs for several stations regionally in an attempt to obtain a qualitative view of the upper mantle structure. Most of the regional stacks do not show clear signs of seismic velocity discontinuities in the upper mantle.

  20. Multimedia Analysis plus Visual Analytics = Multimedia Analytics

    SciTech Connect

    Chinchor, Nancy; Thomas, James J.; Wong, Pak C.; Christel, Michael; Ribarsky, Martin W.

    2010-10-01

    Multimedia analysis has focused on images, video, and to some extent audio and has made progress in single channels excluding text. Visual analytics has focused on the user interaction with data during the analytic process plus the fundamental mathematics and has continued to treat text as did its precursor, information visualization. The general problem we address in this tutorial is the combining of multimedia analysis and visual analytics to deal with multimedia information gathered from different sources, with different goals or objectives, and containing all media types and combinations in common usage.

  1. Analytical Challenges in Biotechnology.

    ERIC Educational Resources Information Center

    Glajch, Joseph L.

    1986-01-01

    Highlights five major analytical areas (electrophoresis, immunoassay, chromatographic separations, protein and DNA sequencing, and molecular structures determination) and discusses how analytical chemistry could further improve these techniques and thereby have a major impact on biotechnology. (JN)

  2. Analyticity without Differentiability

    ERIC Educational Resources Information Center

    Kirillova, Evgenia; Spindler, Karlheinz

    2008-01-01

    In this article we derive all salient properties of analytic functions, including the analytic version of the inverse function theorem, using only the most elementary convergence properties of series. Not even the notion of differentiability is required to do so. Instead, analytical arguments are replaced by combinatorial arguments exhibiting…

  3. Josephson effects in the junction formed by DIII-class topological and s-wave superconductors with an embedded quantum dot

    PubMed Central

    Gao, Zhen; Wang, Xiao-Qi; Shan, Wan-Fei; Wu, Hai-Na; Gong, Wei-Jiang

    2016-01-01

    We investigate the Josephson effects in the junction formed by the indirect coupling between DIII-class topological and s-wave superconductors via an embedded quantum dot. Due to the presence of two kinds of superconductors, three dot-superconductor coupling manners are considered, respectively. As a result, the Josephson current is found to oscillate in period 2π. More importantly, the presence of Majorana doublet in the DIII-class superconductor renders the current finite at the case of zero phase difference, with its sign determined by the fermion parity of such a junction. In addition, the dot-superconductor coupling plays a nontrivial role in adjusting the Josephson current. When the s-wave superconductor couples to the dot in the weak limit, the current direction will have an opportunity to reverse. It is believed that these results will be helpful for understanding the transport properties of the DIII-class superconductor. PMID:27324426

  4. Josephson effects in the junction formed by DIII-class topological and s-wave superconductors with an embedded quantum dot.

    PubMed

    Gao, Zhen; Wang, Xiao-Qi; Shan, Wan-Fei; Wu, Hai-Na; Gong, Wei-Jiang

    2016-01-01

    We investigate the Josephson effects in the junction formed by the indirect coupling between DIII-class topological and s-wave superconductors via an embedded quantum dot. Due to the presence of two kinds of superconductors, three dot-superconductor coupling manners are considered, respectively. As a result, the Josephson current is found to oscillate in period 2π. More importantly, the presence of Majorana doublet in the DIII-class superconductor renders the current finite at the case of zero phase difference, with its sign determined by the fermion parity of such a junction. In addition, the dot-superconductor coupling plays a nontrivial role in adjusting the Josephson current. When the s-wave superconductor couples to the dot in the weak limit, the current direction will have an opportunity to reverse. It is believed that these results will be helpful for understanding the transport properties of the DIII-class superconductor. PMID:27324426

  5. Determination of Bedrock Variations and S-wave Velocity Structure in the NW part of Turkey for Earthquake Hazard Mitigation

    NASA Astrophysics Data System (ADS)

    Ozel, A. O.; Arslan, M. S.; Aksahin, B. B.; Genc, T.; Isseven, T.; Tuncer, M. K.

    2015-12-01

    Tekirdag region (NW Turkey) is quite close to the North Anatolian Fault which is capable of producing a large earthquake. Therefore, earthquake hazard mitigation studies are important for the urban areas close to the major faults. From this point of view, integration of different geophysical methods has important role for the study of seismic hazard problems including seismotectonic zoning. On the other hand, geological mapping and determining the subsurface structure, which is a key to assist management of new developed areas, conversion of current urban areas or assessment of urban geological hazards can be performed by integrated geophysical methods. This study has been performed in the frame of a national project, which is a complimentary project of the cooperative project between Turkey and Japan (JICA&JST), named as "Earthquake and Tsunami Disaster Mitigation in the Marmara Region and Disaster Education". With this principal aim, this study is focused on Tekirdag and its surrounding region (NW of Turkey) where some uncertainties in subsurface knowledge (maps of bedrock depth, thickness of quaternary sediments, basin geometry and seismic velocity structure,) need to be resolved. Several geophysical methods (microgravity, magnetic and single station and array microtremor measurements) are applied and the results are evaluated to characterize lithological changes in the region. Array microtremor measurements with several radiuses are taken in 30 locations and 1D-velocity structures of S-waves are determined by the inversion of phase velocities of surface waves, and the results of 1D structures are verified by theoretical Rayleigh wave modelling. Following the array measurements, single-station microtremor measurements are implemented at 75 locations to determine the predominant frequency distribution. The predominant frequencies in the region range from 0.5 Hz to 8 Hz in study area. On the other hand, microgravity and magnetic measurements are performed on

  6. Shallow seismic exploration of the Keuper layers outcropping on the shoulders of the Rhine Graben using P and S waves

    NASA Astrophysics Data System (ADS)

    Akimova, T.; Marthelot, J.-M.; Zillmer, M.

    2012-04-01

    We have performed several seismic P and S waves profiles in Keuper layers outcropping on the shoulders of the Rhine Graben in order to investigate if the lithological and structural heterogeneity that characterize these layers can be detected at depths less than 100m. These shale and limestone layers contain anhydrite levels and are offset by faults that constitute potential hazards for shallow geothermal drilling. 7 short profiles have been done in the Keuper layers outcropping in Grünern (Baden-Württemberg), and 3 profiles in similar layers outcropping on the opposite shoulder of the Rhine Graben in Flexbourg (Alsace) where ancient gypsum mining is known. We are using a hammer and between 48 to 72 vertical geophones for the P profiles, an Elvis horizontal vibrator (30-160 Hz) and 48 to 72 horizontal geophones for the S profiles. Intervals between geophones and shots varying from 50 cm to 2 m were used. For each profile, the recording spread is at a fixed location. First refracted arrivals are observed up to the maximum offset of 100m. Travel times are adjusted with a layered model with dipping interfaces. The surface layer is characterized by a thickness from 1 to 7 m and velocities VP = 300 m/s and VS = 160 m/s. The underlying layer is characterized by a thickness from 6 to 10 m and velocities VP = 880 m/s and VS = 360 m/s. P velocity larger than 2000 m/s is observed below. The first arrivals indicate the existence of shallow lateral velocity variations. Undulations of the interfaces or the presence of low velocity lenses in the shallow layer are apparent in the refracted arrival times. Strong reflections of refracted waves observed on one profile indicate the existence of steep discontinuities that may indicate subvertical faults. Despite using small spatial sampling of shots and geophones, it has proven difficult to detect shallow reflections except on one P wave profile located close to the ancient gypsum mine in Flexbourg. There, clear reflections from

  7. Joint inversion of normal-mode and finite-frequency S-wave data using an irregular tomographic grid

    NASA Astrophysics Data System (ADS)

    Zaroli, Christophe; Lambotte, Sophie; Lévêque, Jean-Jacques

    2015-12-01

    Global-scale tomographic models should aim at satisfying the full seismic spectrum. For this purpose, and to better constrain isotropic 3-D variations of shear velocities in the mantle, we tackle a joint inversion of spheroidal normal-mode structure coefficients and multiple-frequency S-wave delay times. In all previous studies for which normal modes were jointly inverted for, with body and/or surface waves, the mantle was laterally parametrized with uniform basis functions, such as spherical harmonics, equal-area blocks and evenly spaced spherical splines. In particular, spherical harmonics naturally appear when considering the Earth's free oscillations. However, progress towards higher resolution joint tomography requires a movement away from such uniform parametrization to overcome its computational inefficiency to adapt to local variations in resolution. The main goal of this study is to include normal modes into a joint inversion based upon a non-uniform parametrization that is adapted to the spatially varying smallest resolving length of the data. Thus, we perform the first joint inversion of normal-mode and body-wave data using an irregular tomographic grid, optimized according to ray density. We show how to compute the projection of 3-D sensitivity kernels for both data sets onto our parametrization made up of spherical layers spanned with irregular Delaunay triangulations. This approach, computationally efficient, allows us to map into the joint model multiscale structural informations from data including periods in the 10-51 s range for body waves and 332-2134 s for normal modes. Tomographic results are focused on the 400-2110 km depth range, where our data coverage is the most relevant. We discuss the potential of a better resolution where the grid is fine, compared to spherical harmonics up to degree 40, as the number of model parameters is similar. Our joint model seems to contain coherent structural components beyond degree 40, such as those related

  8. P-Wave and S-Wave Velocity Structure of Submarine Landslide Associated With Gas Hydrate Layer on Frontal Ridge of Northern Cascadia Margin

    NASA Astrophysics Data System (ADS)

    He, T.; Lu, H.; Yelisetti, S.; Spence, G.

    2015-12-01

    The submarine landslide associated with gas hydrate is a potential risk for environment and engineering projects, and thus from long time ago it has been a hot topic of hydrate research. The study target is Slipstream submarine landslide, one of the slope failures observed on the frontal ridges of the Northern Cascadia accretionary margin off Vancouver Island. The previous studies indicated a possible connection between this submarine landslide feature and gas hydrate, whose occurrence is indicated by a prominent bottom-simulating reflector (BSR), at a depth of ~265-275 m beneath the seafloor (mbsf). The OBS (Ocean Bottom Seismometer) data collected during SeaJade (Seafloor Earthquake Array - Japan Canada Cascadia Experiment) project were used to derive the subseafloor velocity structure for both P- and S-wave using travel times picked from refraction and reflection events. The P-wave velocity structure above the BSR showed anomalous high velocities of about 2.0 km/s at shallow depths of 100 mbsf, closely matching the estimated depth of the glide plane (100 ± 10 m). Forward modelling of S-waves was carried out using the data from the OBS horizontal components. The S-wave velocities, interpreted in conjunction with the P-wave results, provide the key constraints on the gas hydrate distribution within the pores. The hydrate distribution in the pores is important for determining concentrations, and also for determining the frame strength which is critical for controlling slope stability of steep frontal ridges. The increase in S-wave velocity suggests that the hydrate is distributed as part of the load-bearing matrix to increase the rigidity of the sediment.

  9. Robustness of s-Wave Pairing in Electron-Overdoped A1-yFe2-xSe2 (A=K,​Cs)

    NASA Astrophysics Data System (ADS)

    Fang, Chen; Wu, Yang-Le; Thomale, Ronny; Bernevig, B. Andrei; Hu, Jiangping

    2011-08-01

    Using self-consistent mean-field and functional renormalization-group approaches, we show that s-wave pairing symmetry is robust in the heavily electron-doped iron chalcogenides AFe2-xSe2, where A=K,​Cs. Recent neutron scattering experiments suggest that the effective nearest-neighbor spin exchange may be ferromagnetic in chalcogenides. This is different from the iron pnictides, where the nearest-neighbor magnetic exchange coupling is believed to be antiferromagnetic and leads to strong competition between s-wave and d-wave pairing in the electron-overdoped region. Our finding of a robust s-wave pairing in (K,​Cs)Fe2-xSe2 differs from the d-wave pairing result obtained by other theories where nonlocal bare interaction terms and the next-to-nearest-neighbor J2 term are underestimated. Detecting the pairing symmetry in (K,​Cs)Fe2-xSe2 may hence provide important insights regarding the mechanism of superconducting pairing in iron-based superconductors.

  10. Scattering of trapped P and S waves in the hydrated subducting crust of the Philippine Sea plate at shallow depths beneath the Kanto region, Japan

    NASA Astrophysics Data System (ADS)

    Takemura, Shunsuke; Yoshimoto, Kazuo; Tonegawa, Takashi

    2015-12-01

    We performed a detailed analysis of seismograms obtained during intraslab earthquakes beneath the Kanto region and revealed a strong lateral variation in the waveforms of high-frequency trapped P and S waves propagating through the subducting crust of the Philippine Sea plate. Significantly distorted spindle-shaped trapped P and S waves with large peak delays were observed in areas where the Philippine Sea plate is at shallow depths beneath the Kanto region. In order to interpret these seismic observations, in relation to the structural properties of the crust of the Philippine Sea plate, we conducted finite difference method simulations of high-frequency seismic wave propagation using various possible heterogeneous velocity structure models. Our simulation successfully reproduced the observed characteristics of the trapped waves and demonstrated that the propagation of high-frequency P and S waves is significantly affected by small-scale velocity heterogeneities in the subducting crust. These heterogeneities can be traced to a depth of approximately 40 km, before disappearing at greater depths, a phenomenon that may be related to dehydration in the subducting crust at shallower depths.

  11. Ultrasonic P and S wave Velocity Measurements at Mid-to-Lower Crustal Conditions of Pressure and Temperature in a Piston Cylinder Apparatus

    NASA Astrophysics Data System (ADS)

    Ishikawa, M.; Arima, M.

    2007-12-01

    In order to interpret seismic structures in terms of rock type, temperature anomaly, degree of partial melting and distribution of fluids, we have carried out research on the elastic properties of the crustal rocks using ultrasonic measurements. We have developed techniques to perform ultrasonic velocity measurements at mid-to-lower crustal conditions of pressure and temperature. These techniques are now been applied to study the rock physics of exposed deep crustal sections and crustal xenoliths, including gabbro, tonalite, granite, anorthosite, granulite and amphibolite, which were collected from the Tanzawa Mountain of central Japan, Kohistan area of Pakistan, Ichinomegata of NE Japan, Takashima and Kurose of SW Japan, and granulite-facies complex of East Antarctica. Compressional (P) and shear (S) wave velocities for these rock specimens are measured in piston cylinder apparatus. In order to compare directly to seismic velocities at the deep island arc pressures and temperatures, we developed ultrasonic velocity measurements using buffer rod technique. Pt buffer rod is used to isolate the piezoelectric transducer from the high-temperature condition. Travel times through the rock sample were determined with the pulse reflection technique. We are developing a method for simultaneous P-wave and S-wave velocity measurements using dual-mode piezoelectric transducer which generates P-waves and S-waves simultaneously. Using these techniques, we can determine Vp/Vs ratio and Poisson's ratio precisely.

  12. Surface seismic measurements of near-surface P-and S-wave seismic velocities at earthquake recording stations, Seattle, Washington

    USGS Publications Warehouse

    Williams, R.A.; Stephenson, W.J.; Frankel, A.D.; Odum, J.K.

    1999-01-01

    We measured P-and S-wave seismic velocities to about 40-m depth using seismic-refraction/reflection data on the ground surface at 13 sites in the Seattle, Washington, urban area, where portable digital seismographs recently recorded earthquakes. Sites with the lowest measured Vs correlate with highest ground motion amplification. These sites, such as at Harbor Island and in the Duwamish River industrial area (DRIA) south of the Kingdome, have an average Vs in the upper 30 m (V??s30) of 150 to 170 m/s. These values of V??s30 place these sites in soil profile type E (V??s30 < 180 m/s). A "rock" site, located at Seward Park on Tertiary sedimentary deposits, has a V??S30 of 433 m/s, which is soil type C (V??s30: 360 to 760 m/s). The Seward Park site V??s30 is about equal to, or up to 200 m/s slower than sites that were located on till or glacial outwash. High-amplitude P-and S-wave seismic reflections at several locations appear to correspond to strong resonances observed in earthquake spectra. An S-wave reflector at the Kingdome at about 17 to 22 m depth probably causes strong 2-Hz resonance that is observed in the earthquake data near the Kingdome.

  13. Dynamical stability of dipolar Bose-Einstein condensates with temporal modulation of the s-wave scattering length.

    PubMed

    Sabari, S; Jisha, Chandroth P; Porsezian, K; Brazhnyi, Valeriy A

    2015-09-01

    We study the stabilization properties of dipolar Bose-Einstein condensate by temporal modulation of short-range two-body interaction. Through both analytical and numerical methods, we analyze the mean-field Gross-Pitaevskii equation with short-range two-body and long-range, nonlocal, dipolar interaction terms. We derive the equation of motion and effective potential of the dipolar condensate by variational method. We show that there is an enhancement of the condensate stability due to the inclusion of dipolar interaction in addition to the two-body contact interaction. We also show that the stability of the dipolar condensate increases in the presence of time varying two-body contact interaction; the temporal modification of the contact interaction prevents the collapse of dipolar Bose-Einstein condensate. Finally we confirm the semi-analytical prediction through the direct numerical simulations of the governing equation. PMID:26465538

  14. EMPIRICAL OBSERVATIONS OF EARTHQUAKE-EXPLOSION DISCRIMINATION USING P/S RATIOS AND IMPLICATIONS FOR THE SOURCES OF EXPLOSION S-WAVES

    SciTech Connect

    Walter, W R; Matzel, E; Pasyanos, M; Harris, D B; Gok, R; Ford, S R

    2007-06-28

    We continue exploring methodologies to improve earthquake-explosion discrimination using regional amplitude ratios such as P/S. The earliest simple source models predicted P/S wave amplitudes for explosions should be much larger than for earthquakes across the body wave spectrum. However empirical observations show the separation of explosions from earthquakes using regional P/S amplitudes is strongly frequency dependent, with relatively poor separation at low frequencies ({approx} 1 Hz) and relatively good separation at high frequencies (> {approx}3 Hz). We demonstrate this using closely located pairs of earthquakes and explosions recorded on common, publicly available stations at test sites around the world e.g. Nevada, Lop Nor, Novaya Zemlya, Semipalatinsk, India, Pakistan, and North Korea. We show this pattern appears to have little dependence on the point source variability revealed by longer period surface wave modeling. For example regional waveform modeling shows strong tectonic release from the May 1998 India test in contrast with very little tectonic release in the recent North Korea test, but the P/S discrimination behavior is similar in both events, using the limited regional data available. While accepted explosion P-wave models have been available for many years, the frequency behavior of the P/S discriminant has inspired a variety of competing models to explain how explosions generate S-waves. We briefly review some of these models in the context of the P/S discriminant observations. One hypothesis is that S-waves are generated mainly from conversion of P-waves and surface waves, so S-waves from explosions can be predicted from the P-wave models via a frequency dependent transfer function. A different hypothesis is that significant generation of S-waves comes from the CLVD (compensated linear vector dipole) component created by spall above the explosion. A recent model by Fisk (2006) shows the explosion S-wave spectra can be modeled using the P

  15. A non-parametric method for automatic determination of P-wave and S-wave arrival times: application to local micro earthquakes

    NASA Astrophysics Data System (ADS)

    Rawles, Christopher; Thurber, Clifford

    2015-08-01

    We present a simple, fast, and robust method for automatic detection of P- and S-wave arrivals using a nearest neighbours-based approach. The nearest neighbour algorithm is one of the most popular time-series classification methods in the data mining community and has been applied to time-series problems in many different domains. Specifically, our method is based on the non-parametric time-series classification method developed by Nikolov. Instead of building a model by estimating parameters from the data, the method uses the data itself to define the model. Potential phase arrivals are identified based on their similarity to a set of reference data consisting of positive and negative sets, where the positive set contains examples of analyst identified P- or S-wave onsets and the negative set contains examples that do not contain P waves or S waves. Similarity is defined as the square of the Euclidean distance between vectors representing the scaled absolute values of the amplitudes of the observed signal and a given reference example in time windows of the same length. For both P waves and S waves, a single pass is done through the bandpassed data, producing a score function defined as the ratio of the sum of similarity to positive examples over the sum of similarity to negative examples for each window. A phase arrival is chosen as the centre position of the window that maximizes the score function. The method is tested on two local earthquake data sets, consisting of 98 known events from the Parkfield region in central California and 32 known events from the Alpine Fault region on the South Island of New Zealand. For P-wave picks, using a reference set containing two picks from the Parkfield data set, 98 per cent of Parkfield and 94 per cent of Alpine Fault picks are determined within 0.1 s of the analyst pick. For S-wave picks, 94 per cent and 91 per cent of picks are determined within 0.2 s of the analyst picks for the Parkfield and Alpine Fault data set

  16. Science Update: Analytical Chemistry.

    ERIC Educational Resources Information Center

    Worthy, Ward

    1980-01-01

    Briefly discusses new instrumentation in the field of analytical chemistry. Advances in liquid chromatography, photoacoustic spectroscopy, the use of lasers, and mass spectrometry are also discussed. (CS)

  17. Analytical Chemistry in Industry.

    ERIC Educational Resources Information Center

    Kaiser, Mary A.; Ullman, Alan H.

    1988-01-01

    Clarifies the roles of a practicing analytical chemist in industry: quality control, methods and technique development, troubleshooting, research, and chemical analysis. Lists criteria for success in industry. (ML)

  18. P-wave and S-wave traveltime residuals in Caledonian and adjacent units of Northern Europe and Greenland

    NASA Astrophysics Data System (ADS)

    Hejrani, Babak; Balling, Niels; Holm Jacobsen, Bo; Kind, Rainer; Tilmann, Frederik; England, Richard; Bom Nielsen, Søren

    2014-05-01

    This work combines P-wave and S-wave travel time residuals from in total 477 temporary and 56 permanent stations deployed across Caledonian and adjacent units in Northern Europe and Greenland (Tor, Gregersen et al. 2002; SVEKALAPKO, Sandoval et al., 2003; CALAS, Medhus et al, 2012a; MAGNUS, Weidle et al. 2010; SCANLIPS south, England & Ebbing 2012; SCANLIPS north, Hejrani et al. 2012; JULS Hejrani et al. 2013; plus permanent stations in the region). We picked data from 2002 to 2012 (1221 events) using a cross correlation technique on all waveforms recorded for each event. In this way we achieve maximum consistency of relative residuals over the whole region (Medhus et al. 2012b). On the European side 18362 P-wave travel time residuals was delivered. In East Greenland 1735 P-wave residuals were recovered at the Central Fjord array (13 stations) and 2294 residuals from the sparse GLISN-array (23 stations). Likewise, we picked a total of 6034 residuals of the SV phase (For the Tor and SVEKALAPKO projects we used data from Amaru et al. 2008). Relative residuals within the region are mainly due to sub-crustal uppermost mantle velocity anomalies. A dominant subvertical boundary was detected by Medhus et al. (2012), running along the Tornquist zone, east of the Oslo Graben and crossing under high topography of the southern Scandes. We delineated this boundary in more detail, tracking it towards the Atlantic margin north of Trondheim. Further north (Scanlips north), a similar subvertical upper mantle boundary seems to be present close to the coast, coinciding with the edge of the stretched crust. The North German Caledonides were probed by the new JULS (JUtland Lower Saxony) profile which closes the gap between Tor and CALAS arrays. Mantle structure found by the Tor project was confirmed, and modelling was extended to the eastern edge of the North Sea. References: Amaru, M. L., Spakman, W., Villaseñor, A., Sandoval, S., Kissling, E., 2008, A new absolute arrival time data

  19. Learning Analytics Considered Harmful

    ERIC Educational Resources Information Center

    Dringus, Laurie P.

    2012-01-01

    This essay is written to present a prospective stance on how learning analytics, as a core evaluative approach, must help instructors uncover the important trends and evidence of quality learner data in the online course. A critique is presented of strategic and tactical issues of learning analytics. The approach to the critique is taken through…

  20. Analytical mass spectrometry

    SciTech Connect

    Not Available

    1990-01-01

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  1. Analytical mass spectrometry. Abstracts

    SciTech Connect

    Not Available

    1990-12-31

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  2. Process Analytical Chemistry.

    ERIC Educational Resources Information Center

    Callis, James B.; And Others

    1987-01-01

    Discusses process analytical chemistry as a discipline designed to supply quantitative and qualitative information about a chemical process. Encourages academic institutions to examine this field for employment opportunities for students. Describes the five areas of process analytical chemistry, including off-line, at-line, on-line, in-line, and…

  3. Extreme Scale Visual Analytics

    SciTech Connect

    Wong, Pak C.; Shen, Han-Wei; Pascucci, Valerio

    2012-05-08

    Extreme-scale visual analytics (VA) is about applying VA to extreme-scale data. The articles in this special issue examine advances related to extreme-scale VA problems, their analytical and computational challenges, and their real-world applications.

  4. Validating Analytical Methods

    ERIC Educational Resources Information Center

    Ember, Lois R.

    1977-01-01

    The procedures utilized by the Association of Official Analytical Chemists (AOAC) to develop, evaluate, and validate analytical methods for the analysis of chemical pollutants are detailed. Methods validated by AOAC are used by the EPA and FDA in their enforcement programs and are granted preferential treatment by the courts. (BT)

  5. Teaching the Analytical Life

    ERIC Educational Resources Information Center

    Jackson, Brian

    2010-01-01

    Using a survey of 138 writing programs, I argue that we must be more explicit about what we think students should get out of analysis to make it more likely that students will transfer their analytical skills to different settings. To ensure our students take analytical skills with them at the end of the semester, we must simplify the task we…

  6. Signals: Applying Academic Analytics

    ERIC Educational Resources Information Center

    Arnold, Kimberly E.

    2010-01-01

    Academic analytics helps address the public's desire for institutional accountability with regard to student success, given the widespread concern over the cost of higher education and the difficult economic and budgetary conditions prevailing worldwide. Purdue University's Signals project applies the principles of analytics widely used in…

  7. Quo vadis, analytical chemistry?

    PubMed

    Valcárcel, Miguel

    2016-01-01

    This paper presents an open, personal, fresh approach to the future of Analytical Chemistry in the context of the deep changes Science and Technology are anticipated to experience. Its main aim is to challenge young analytical chemists because the future of our scientific discipline is in their hands. A description of not completely accurate overall conceptions of our discipline, both past and present, to be avoided is followed by a flexible, integral definition of Analytical Chemistry and its cornerstones (viz., aims and objectives, quality trade-offs, the third basic analytical reference, the information hierarchy, social responsibility, independent research, transfer of knowledge and technology, interfaces to other scientific-technical disciplines, and well-oriented education). Obsolete paradigms, and more accurate general and specific that can be expected to provide the framework for our discipline in the coming years are described. Finally, the three possible responses of analytical chemists to the proposed changes in our discipline are discussed. PMID:26631024

  8. Scalar resonances in a unitary {pi}{pi} S-wave model for D{sup +} {r_arrow} {pi}{sup+}{pi}{sup-}{pi}{sup+}.

    SciTech Connect

    Boito, D. R.; Dedonder, J.-P.; El-Bennich, B.; Leitner, O.; Loiseau, B.; Physics; Univ. Autonoma de Barcelona; Univ. de Sao Paulo; Univ. Paris; Pl. Jussieu; Lab. Nazionali de Frascati

    2009-02-19

    We propose a model for D{sup +} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup +} decays following experimental results which indicate that the two-pion interaction in the S wave is dominated by the scalar resonances f{sub 0}(600)/{sigma} and f{sub 0}(980). The weak decay amplitude for D{sup +} {yields} R{pi}{sup +}, where R is a resonance that subsequently decays into {pi}{sup +}{pi}{sup -}, is constructed in a factorization approach. In the S wave, we implement the strong decay R {yields} {pi}{sup +}{pi}{sup -} by means of a scalar form factor. This provides a unitary description of the pion-pion interaction in the entire kinematically allowed mass range m{sub {pi}{pi}}{sup 2} from threshold to about 3 GeV{sup 2}. In order to reproduce the experimental Dalitz plot for D{sup +} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup +}, we include contributions beyond the S wave. For the P wave, dominated by the {rho}(770){sup 0}, we use a Breit-Wigner description. Higher waves are accounted for by using the usual isobar prescription for the f{sub 2}(1270) and {rho}(1450){sup 0}. The major achievement is a good reproduction of the experimental m{sub {pi}{pi}}{sup 2} distribution, and of the partial as well as the total D{sup +} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup +} branching ratios. Our values are generally smaller than the experimental ones. We discuss this shortcoming and, as a by-product, we predict a value for the poorly known D {yields} {sigma} transition form factor at q{sup 2} = m{sub {pi}}{sup 2}.

  9. Six-degree-of-freedom near-source seismic motions II: examples of real seismogram analysis and S-wave velocity retrieval

    NASA Astrophysics Data System (ADS)

    Brokešová, Johana; Málek, Jiří

    2015-04-01

    Near-source records obtained by the mechanical seismic sensor Rotaphone are presented. The Rotaphone can measure six components of seismic movements, three translational and three rotational. The apparent S-wave phase velocity is determined and the possibility to obtain the wavepath S-wave velocity directly under the receiver is discussed. Rotation-to-translation ratios (RTRs) characterize the strength of rotations compared to translations. The Rotaphone records of local microearthquakes were obtained in various European seismoactive regions over the last few years. Three case studies, analyzed in detail, include various geological structures and seismograms recorded at various epicentral distances from 0.7 to 14.9 km. Also, the source depth varies from 4.8 to 10.4 km. The first case is an event from the West Bohemia intraplate seismic swarm region. The seismogram was recorded only 0.7 km from the epicenter. This case shows the complexity of rotation-to-translational relations near the epicenter. The second case is from the Corinthian Gulf active-rift region. The study confirms the expectation of the theory concerning rotations connected with the direct S wave; however, difficulties follow from a very complex 3D geological structure in the vicinity of the station, complicated by a distinctive topography with steep slopes of the hills. The third example is from South Iceland, near the active Katla volcano. The data in this case satisfy the rotation-to-translation relations very well, which is probably caused by the relatively simple geological setting and appropriate source-to-receiver configuration. The RTRs are computed for all three cases, and their frequency dependence is discussed.

  10. P and S wave tomography of Japan subduction zone from joint inversions of local and teleseismic travel times and surface-wave data

    NASA Astrophysics Data System (ADS)

    Liu, Xin; Zhao, Dapeng

    2016-03-01

    We determined P and S wave velocity tomography of the Japan subduction zone down to a depth of 700 km by conducting joint inversions of a large number of high-quality arrival-time data of local earthquakes and teleseismic events which are newly collected for this study. We also determined 2-D phase-velocity images of fundamental mode Rayleigh waves at periods of 20-150 s beneath Japan and the surrounding oceanic regions using amplitude and phase data of teleseismic Rayleigh waves. A detailed 3-D S-wave tomography of the study region is obtained by jointly inverting S-wave arrival times of local and teleseismic events and the Rayleigh-wave phase-velocity data. Our inversion results reveal the subducting Pacific and Philippine Sea slabs clearly as dipping high-velocity zones from a 1-D starting velocity model. Prominent low-velocity (low-V) anomalies are revealed in the mantle wedge above the slabs and in the mantle below the Pacific slab. The distinct velocity contrasts between the subducting slabs and the surrounding mantle reflect significant lateral variations in temperature as well as water content and/or the degree of partial melting. The low-V anomalies in the mantle wedge are attributed to slab dehydration and corner flows in the mantle wedge. A sheet-like low-V zone is revealed under the Pacific slab beneath NE Japan, which may reflect hot upwelling from the deeper mantle and subduction of a plume-fed asthenosphere as well. Our present results indicate that joint inversions of different seismic data are very effective and important for obtaining robust tomographic images of the crust and mantle.

  11. S-wave attenuation in northeastern Sonora, Mexico, near the faults that ruptured during the earthquake of 3 May 1887 Mw 7.5.

    PubMed

    Villalobos-Escobar, Gina P; Castro, Raúl R

    2014-01-01

    We used a new data set of relocated earthquakes recorded by the Seismic Network of Northeastern Sonora, Mexico (RESNES) to characterize the attenuation of S-waves in the fault zone of the 1887 Sonora earthquake (M w 7.5). We determined spectral attenuation functions for hypocentral distances (r) between 10 and 140 km using a nonparametric approach and found that in this fault zone the spectral amplitudes decay slower with distance at low frequencies (f < 4 Hz) compared to those reported in previous studies in the region using more distant recordings. The attenuation functions obtained for 23 frequencies (0.4 ≤ f ≤ 63.1 Hz) permit us estimating the average quality factor Q S  = (141 ± 1.1 )f ((0.74 ± 0.04)) and a geometrical spreading term G(r) = 1/r (0.21). The values of Q estimated for S-wave paths traveling along the fault system that rupture during the 1887 event, in the north-south direction, are considerably lower than the average Q estimated using source-station paths from multiple stations and directions. These results indicate that near the fault zone S waves attenuate considerably more than at regional scale, particularly at low frequencies. This may be the result of strong scattering near the faults due to the fractured upper crust and higher intrinsic attenuation due to stress concentration near the faults. PMID:25674476

  12. Comparison of P- and S-waves velocities estimated from Biot-Gassmann and Kuster-Toksöz models with results obtained from acoustic wavetrains interpretation

    NASA Astrophysics Data System (ADS)

    BałA, Maria; Cichy, Adam

    2007-06-01

    Kuster-Toksöz and Biot-Gassmann models for estimating velocities of longitudinal and shear waves on the basis of well-logging data were analysed. P-wave and S-wave velocity models are crucial for interpretation of seismic data. Discussed models enable determination with quite good accuracy, in some cases higher than the acoustic full wavetrains interpretation. Because velocity strongly depends on lithology and saturation of pore space, the selection of parameters of rock matrix, hydrocarbons and formation waters has a strong effect on the quality of velocities estimation.

  13. S-wave triplet doubly-excited states 3Se of Li+ below the N=2 excitation threshold of Li2+

    NASA Astrophysics Data System (ADS)

    Gien, T. T.

    2009-11-01

    The Harris-Nesbet variational method was considered for the determination of the series a and b of S-wave triplet doubly-excited-state resonances 3Se of Li+ below the N=2 excitation threshold of Li2+. Because of the high accuracy of our numerical method, we succeeded in determining a greatest number of these doubly-excited states below this threshold, including those lying very close to the threshold. Five of these high-lying doubly excited states were determined by us for the first time.

  14. Numerical Simulations of Surface Topography Effects on Shallow Explosion Ground Motions with Applications to S-Wave Generation and North Korean Nuclear Tests

    NASA Astrophysics Data System (ADS)

    Rodgers, A. J.; Lay, T.

    2014-12-01

    Observations of nuclear explosions ubiquitously reveal shear-waves in the form of high-frequency Sn and Lg at regional distances and long-period surface waves at teleseismic distances. While a number of mechanisms have been shown to generate shear-waves from explosions, including non-linear processes near the source, elastic scattering and tectonic release, it is likely that all mechanisms act to some extent in each emplacement scenario. We performed numerical simulations of seismic ground motions excited by shallow explosions in the presence of rough surface topography to investigate elastic scattering and mode-conversion mechanisms of S-wave generation. Massively parallel simulations were performed at high-resolution to capture the high frequencies (up to 8 Hz) of interest to low-yield nuclear explosion monitoring. Simulations were performed with SW4, an elastic finite difference code that uses a conforming curvilinear mesh to model the near-surface region with a non-planar free surface. Results show that the rough free surface generates significant S-waves by P-to-Rg scattering. We performed simulations with real surface topography from the North Korean (DPRK) nuclear test site and synthetic stochastic topography to investigate how surface topography governs local and regional distance S-waves. We find that S-wave amplitudes along the surface in the presence of topography are increased several-fold on average within 10 km of the source. Topographic scattering leads to SH amplitudes of up to 50% of SV within 10 km, leading to equipartitioning of shear wave energy on the horizontal components. Scattered energy between the direct P and Rg waves has the amplitude spectra of the direct P-wave but travels with the Rg velocity, clearly illustrating the P-to-Rg mechanism for shear-wave generation. The amplitude spectra of Rg waves in the presence of topography are shaped by the low frequency (0.5-2.5 Hz) peaked spectrum of the flat case plus the high frequency (> 2 Hz

  15. Enzymes in Analytical Chemistry.

    ERIC Educational Resources Information Center

    Fishman, Myer M.

    1980-01-01

    Presents tabular information concerning recent research in the field of enzymes in analytic chemistry, with methods, substrate or reaction catalyzed, assay, comments and references listed. The table refers to 128 references. Also listed are 13 general citations. (CS)

  16. Analytical techniques: A compilation

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A compilation, containing articles on a number of analytical techniques for quality control engineers and laboratory workers, is presented. Data cover techniques for testing electronic, mechanical, and optical systems, nondestructive testing techniques, and gas analysis techniques.

  17. Extreme Scale Visual Analytics

    SciTech Connect

    Steed, Chad A; Potok, Thomas E; Pullum, Laura L; Ramanathan, Arvind; Shipman, Galen M; Thornton, Peter E

    2013-01-01

    Given the scale and complexity of today s data, visual analytics is rapidly becoming a necessity rather than an option for comprehensive exploratory analysis. In this paper, we provide an overview of three applications of visual analytics for addressing the challenges of analyzing climate, text streams, and biosurveilance data. These systems feature varying levels of interaction and high performance computing technology integration to permit exploratory analysis of large and complex data of global significance.

  18. Investigating P- and S-wave velocity structure beneath the Marmara region (Turkey) and the surrounding area from local earthquake tomography

    NASA Astrophysics Data System (ADS)

    Polat, Gulten; Özel, Nurcan Meral; Koulakov, Ivan

    2016-07-01

    We investigated the crustal structure beneath the Marmara region and the surrounding area in the western part of the North Anatolian fault zone. These areas have high seismicity and are of critical significance to earthquake hazards. The study was based on travel-time tomography using local moderate and micro-earthquakes occurring in the study area recorded by the Multi-Disciplinary Earthquake Research in High Risk Regions of Turkey project and Kandilli Observatory and Earthquake Research Institute. We selected 2131 earthquakes and a total of 92,858 arrival times, consisting of 50,044 P-wave and 42,814 S-wave arrival times. We present detailed crustal structure down to 50 km depth beneath the Marmara region for P- and S-wave velocities using the LOTOS code based on iterative inversion. We used the distributions of the resulting seismic parameters ( Vp, Vs) to pick out significant geodynamical features. The high-velocity anomalies correlate well with fracturing segments of the North Anatolian fault. High seismicity is mostly concentrated in these segments. In particular, low velocities were observed beneath the central Marmara Sea at 5 km depth.

  19. Universality in s-wave and higher partial-wave Feshbach resonances: An illustration with a single atom near two scattering centers

    NASA Astrophysics Data System (ADS)

    Zhu, Shangguo; Tan, Shina

    2013-06-01

    It is well-known that cold atoms near s-wave Feshbach resonances have universal properties that are insensitive to the short-range details of the interaction. What is less known is that atoms near higher partial-wave Feshbach resonances also have remarkable universal properties. We illustrate this with a single atom interacting resonantly with two fixed static centers. At a Feshbach resonance point with orbital angular momentum L≥1, we find 2L+1 shallow bound states whose energies behave like 1/R2L+1 when the distance R between the two centers is large. We then compute corrections to the binding energies due to other parameters in the effective range expansions. For completeness we also compute the binding energies near s-wave Feshbach resonances, taking into account the corrections. Afterwards we turn to the bound states at large but finite scattering volumes. For p-wave and higher partial-wave resonances we derive a simple formula for the energies in terms of a parameter called “proximity parameter.” These results are applicable to a free atom interacting resonantly with two atoms that are localized to two lattice sites of an optical lattice, and to one light atom interacting with two heavy ones in free space. Modifications of the low energy physics due to the long range van der Waals potential are also discussed.

  20. Orthogonal relation between wavefield polarization and fast S wave direction in the Val d'Agri region: An integrating method to investigate rock anisotropy

    NASA Astrophysics Data System (ADS)

    Pischiutta, M.; Pastori, M.; Improta, L.; Salvini, F.; Rovelli, A.

    2014-01-01

    polarization is investigated using 200 seismograms recorded by a network of 20 stations installed on rock outcrops in the Val d'Agri region that hosts the largest oil fields in the southern Apennines (Italy). Polarization is assessed both in the frequency and time domains through the individual-station horizontal-to-vertical spectral ratio and covariance-matrix analysis, respectively. We find that most of the stations show a persistent horizontal polarization of waveforms, with a NE-SW predominant trend. This direction is orthogonal to the general trend of Quaternary normal faults in the region and to the maximum horizontal stress related to the present extensional regime. According to previous studies in other areas, such a directional effect is interpreted as due to the presence of fault-related fracture fields, polarization being orthogonal to their predominant direction. A comparison with S wave anisotropy inferred from shear wave splitting indicates an orthogonal relation between horizontal polarization and fast S wave direction. This suggests that wavefield polarization and fast velocity direction are effects of the same cause: The existence of an anisotropic medium represented by fractured rocks where shear wave velocity is larger in the crack-parallel component and compliance is larger perpendicularly to the crack strike. The latter is responsible for the observed anisotropic pattern of amplitudes of horizontal ground motion in the study area.

  1. Advances in analytical chemistry

    NASA Technical Reports Server (NTRS)

    Arendale, W. F.; Congo, Richard T.; Nielsen, Bruce J.

    1991-01-01

    Implementation of computer programs based on multivariate statistical algorithms makes possible obtaining reliable information from long data vectors that contain large amounts of extraneous information, for example, noise and/or analytes that we do not wish to control. Three examples are described. Each of these applications requires the use of techniques characteristic of modern analytical chemistry. The first example, using a quantitative or analytical model, describes the determination of the acid dissociation constant for 2,2'-pyridyl thiophene using archived data. The second example describes an investigation to determine the active biocidal species of iodine in aqueous solutions. The third example is taken from a research program directed toward advanced fiber-optic chemical sensors. The second and third examples require heuristic or empirical models.

  2. The upper mantle structure of the central Rio Grande rift region from teleseismic P and S wave travel time delays and attenuation

    USGS Publications Warehouse

    Slack, P.D.; Davis, P.M.; Baldridge, W.S.; Olsen, K.H.; Glahn, A.; Achauer, U.; Spence, W.

    1996-01-01

    The lithosphere beneath a continental rift should be significantly modified due to extension. To image the lithosphere beneath the Rio Grande rift (RGR), we analyzed teleseismic travel time delays of both P and S wave arrivals and solved for the attenuation of P and S waves for four seismic experiments spanning the Rio Grande rift. Two tomographic inversions of the P wave travel time data are given: an Aki-Christofferson-Husebye (ACH) block model inversion and a downward projection inversion. The tomographic inversions reveal a NE-SW to NNE-SSW trending feature at depths of 35 to 145 km with a velocity reduction of 7 to 8% relative to mantle velocities beneath the Great Plains. This region correlates with the transition zone between the Colorado Plateau and the Rio Grande rift and is bounded on the NW by the Jemez lineament, a N52??E trending zone of late Miocene to Holocene volcanism. S wave delays plotted against P wave delays are fit with a straight line giving a slope of 3.0??0.4. This correlation and the absolute velocity reduction imply that temperatures in the lithosphere are close to the solidus, consistent with, but not requiring, the presence of partial melt in the mantle beneath the Rio Grande rift. The attenuation data could imply the presence of partial melt. We compare our results with other geophysical and geologic data. We propose that any north-south trending thermal (velocity) anomaly that may have existed in the upper mantle during earlier (Oligocene to late Miocene) phases of rifting and that may have correlated with the axis of the rift has diminished with time and has been overprinted with more recent structure. The anomalously low-velocity body presently underlying the transition zone between the core of the Colorado Plateau and the rift may reflect processes resulting from the modern (Pliocene to present) regional stress field (oriented WNW-ESE), possibly heralding future extension across the Jemez lineament and transition zone.

  3. AN INVESTIGATION TO DOCUMENT MORROW RESERVOIRS THAT CAN BE BETTER DETECTED WITH SEISMIC SHEAR (S) WAVES THAN WITH COMPRESSIONAL (P) WAVES

    SciTech Connect

    Thomas Cottman

    2001-10-19

    Pennsylvanian-age Morrow reservoirs are a key component of a large fluvial-deltaic system that extends across portions of Colorado, Kansas, Oklahoma, and Texas. A problem that operators have to solve in some Morrow plays in this multi-state area is that many of the fluvial channels within the Morrow interval are invisible to seismic compressional (P) waves. This P-wave imaging problem forces operators in such situations to site infill, field-extension, and exploration wells without the aid of 3-D seismic technology. The objective of this project was to develop and demonstrate seismic technology that can improve drilling success in Morrow plays. Current P-wave technology commonly results in 80-percent of Morrow exploration wells not penetrating economic reservoir facies. Studies at Colorado School of Mines have shown that some of the Morrow channels that are elusive as P-wave targets create robust shear (S) wave reflections (Rampton, 1995). These findings caused Visos Energy to conclude that exploration and field development of Morrow prospects should be done by a combination of P-wave and S-wave seismic imaging. To obtain expanded information about the P and S reflectivity of Morrow facies, 9-component vertical seismic profile (9-C VSP) data were recorded at three locations along the Morrow trend. These data were processed to create P and S images of Morrow stratigraphy. These images were then analyzed to determine if S waves offer an alternative to P waves, or perhaps even an advantage over P waves, in imaging Morrow reservoir targets. The study areas where these field demonstrations were done are defined in Figure 1. Well A was in Sherman County, Texas; well B in Clark County, Kansas; and well C in Cheyenne County, Colorado. Technology demonstrated at these sites can be applied over a wide geographical area and influence operators across the multi-state region spanned by Morrow channel plays. The scope of the investigation described here is significant on the

  4. Frontiers in analytical chemistry

    SciTech Connect

    Amato, I.

    1988-12-15

    Doing more with less was the modus operandi of R. Buckminster Fuller, the late science genius, and inventor of such things as the geodesic dome. In late September, chemists described their own version of this maxim--learning more chemistry from less material and in less time--in a symposium titled Frontiers in Analytical Chemistry at the 196th National Meeting of the American Chemical Society in Los Angeles. Symposium organizer Allen J. Bard of the University of Texas at Austin assembled six speakers, himself among them, to survey pretty widely different areas of analytical chemistry.

  5. Type-IV Superconductivity Phenomenon: Cooper Pairs with Broken Parity and Spin-Rotational Symmetries in D- and S-wave Singlet Superconductors

    NASA Astrophysics Data System (ADS)

    Lebed, Andrei

    2006-03-01

    Paramagnetic effects are shown to result in the appearance of a triplet component of order parameter in vortex phases of d- and s-wave singlet superconductors in the absence of impurities. This component, which breaks both parity and spin-rotational symmetries of Cooper pairs, is expected to be of the order of unity in a number of modern superconductors such as high-Tc, organic, MgB2, and some others. A generic phase diagram of such type-IV superconductors [1], which are singlet ones at H=0 and in the Meissner phase and characterized by singlet-triplet mixed Copper pairs, δs+iδt, in a vortex phase, is suggested. [1] A.G. Lebed, Physical Review Letters, accepted (2006).

  6. s-wave threshold in electron attachment - Results in 2-C4F6 and CFCl3 at ultra-low electron energies

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Alajajian, S. H.; Ajello, J. M.; Orient, O. J.

    1984-01-01

    Electron attachment lineshapes and cross sections are reported for the processes 2-C4F6(-)/2-C4F6 and Cl(-)/CFCl3 at electron energies of 0-120 and 0-140 meV, and at resolutions of 6 and 7 meV (FWHM), respectively. As in previous measurements in CCl4 and SF6, the results show resolution-limited narrow structure in the cross section at electron energies below 15 meV. This structure arises from the divergence of the s-wave cross section in the limit of zero electron energy. Comparisons are given with swarm-measured results, and with collisional ionization (high-Rydberg attachment) data in this energy range.

  7. Volovik effect and Fermi-liquid behavior in the s-wave superconductor CaPd2As2: As75 NMR-NQR measurements

    DOE PAGESBeta

    Ding, Q. -P.; Wiecki, P.; Anand, V. K.; Sangeetha, N. S.; Lee, Y.; Johnston, D. C.; Furukawa, Y.

    2016-04-07

    The electronic and magnetic properties of the collapsed-tetragonal CaPd2As2 superconductor (SC) with a transition temperature of 1.27 K have been investigated by 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. The temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T1) and the Knight shifts indicate the absence of magnetic correlations in the normal state. In the SC state, 1/T1 measured by 75As NQR shows a clear Hebel-Slichter (HS) peak just below Tc and decreases exponentially at lower T, confirming a conventional s-wave SC. Additionally, the Volovik effect, also known as the Doppler shift effect, hasmore » been clearly evidenced by the observation of the suppression of the HS peak with applied magnetic field.« less

  8. Volovik effect and Fermi-liquid behavior in the s -wave superconductor CaPd2As2: 75As NMR-NQR measurements

    NASA Astrophysics Data System (ADS)

    Ding, Q.-P.; Wiecki, P.; Anand, V. K.; Sangeetha, N. S.; Lee, Y.; Johnston, D. C.; Furukawa, Y.

    2016-04-01

    The electronic and magnetic properties of the collapsed-tetragonal CaPd2As2 superconductor (SC) with a transition temperature of 1.27 K have been investigated by 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. The temperature (T ) dependence of the nuclear spin lattice relaxation rates (1 /T1) and the Knight shifts indicate the absence of magnetic correlations in the normal state. In the SC state, 1 /T1 measured by 75As NQR shows a clear Hebel-Slichter (HS) peak just below Tc and decreases exponentially at lower T , confirming a conventional s -wave SC. In addition, the Volovik effect, also known as the Doppler shift effect, has been clearly evidenced by the observation of the suppression of the HS peak with applied magnetic field.

  9. Final Data Report: P- and S-Wave Velocity Logging Borings C4993, C4996, and C4997 Part A: Interval Logs

    SciTech Connect

    Steller, Robert; Diehl, John

    2007-02-01

    Insitu borehole P- and S-wave velocity measurements were collected in three borings located within the Waste Treatment Plant (WTP) boundaries at the Hanford Site, southeastern Washington. Geophysical data acquisition was performed between August and October of 2006 by Rob Steller, Charles Carter, Antony Martin and John Diehl of GEOVision. Data analysis was performed by Rob Steller and John Diehl, and reviewed by Antony Martin of GEOVision, and report preparation was performed by John Diehl and reviewed by Rob Steller. The work was performed under subcontract with Battelle, Pacific Northwest Division with Marty Gardner as Battelle’s Technical Representative and Alan Rohay serving as the Technical Administrator for Pacific Northwest National Laboratory (PNNL). This report describes the field measurements, data analysis, and results of this work.

  10. Final Data Report: P- and S-Wave Velocity Logging Borings C4993, C4996, and C4997 Part B: Overall Logs

    SciTech Connect

    Diehl, John; Steller, Robert

    2007-03-20

    Insitu borehole P- and S-wave velocity measurements were collected in three borings located within the Waste Treatment Plant (WTP) boundaries at the Hanford Site, southeastern Washington. Geophysical data acquisition was performed between August and October of 2006 by Rob Steller, Charles Carter, Antony Martin and John Diehl of GEOVision. Data analysis was performed by Rob Steller and John Diehl, and reviewed by Antony Martin of GEOVision, and report preparation was performed by John Diehl and reviewed by Rob Steller. The work was performed under subcontract with Battelle, Pacific Northwest Division with Marty Gardner as Battelle’s Technical Representative and Alan Rohay serving as the Technical Administrator for Pacific Northwest National Laboratory (PNNL). This report describes the field measurements, data analysis, and results of this work.

  11. Analytical Chemistry Laboratory

    NASA Technical Reports Server (NTRS)

    Anderson, Mark

    2013-01-01

    The Analytical Chemistry and Material Development Group maintains a capability in chemical analysis, materials R&D failure analysis and contamination control. The uniquely qualified staff and facility support the needs of flight projects, science instrument development and various technical tasks, as well as Cal Tech.

  12. Analytical Services Management System

    Energy Science and Technology Software Center (ESTSC)

    2005-03-30

    Analytical Services Management System (ASMS) provides sample management services. Sample management includes sample planning for analytical requests, sample tracking for shipping and receiving by the laboratory, receipt of the analytical data deliverable, processing the deliverable and payment of the laboratory conducting the analyses. ASMS is a web based application that provides the ability to manage these activities at multiple locations for different customers. ASMS provides for the assignment of single to multiple samples for standardmore » chemical and radiochemical analyses. ASMS is a flexible system which allows the users to request analyses by line item code. Line item codes are selected based on the Basic Ordering Agreement (BOA) format for contracting with participating laboratories. ASMS also allows contracting with non-BOA laboratories using a similar line item code contracting format for their services. ASMS allows sample and analysis tracking from sample planning and collection in the field through sample shipment, laboratory sample receipt, laboratory analysis and submittal of the requested analyses, electronic data transfer, and payment of the laboratories for the completed analyses. The software when in operation contains business sensitive material that is used as a principal portion of the Kaiser Analytical Management Services business model. The software version provided is the most recent version, however the copy of the application does not contain business sensitive data from the associated Oracle tables such as contract information or price per line item code.« less

  13. Analytics: Changing the Conversation

    ERIC Educational Resources Information Center

    Oblinger, Diana G.

    2013-01-01

    In this third and concluding discussion on analytics, the author notes that we live in an information culture. We are accustomed to having information instantly available and accessible, along with feedback and recommendations. We want to know what people think and like (or dislike). We want to know how we compare with "others like me."…

  14. Social Learning Analytics

    ERIC Educational Resources Information Center

    Buckingham Shum, Simon; Ferguson, Rebecca

    2012-01-01

    We propose that the design and implementation of effective "Social Learning Analytics (SLA)" present significant challenges and opportunities for both research and enterprise, in three important respects. The first is that the learning landscape is extraordinarily turbulent at present, in no small part due to technological drivers. Online social…

  15. Challenges for Visual Analytics

    SciTech Connect

    Thomas, James J.; Kielman, Joseph

    2009-09-23

    Visual analytics has seen unprecedented growth in its first five years of mainstream existence. Great progress has been made in a short time, yet great challenges must be met in the next decade to provide new technologies that will be widely accepted by societies throughout the world. This paper sets the stage for some of those challenges in an effort to provide the stimulus for the research, both basic and applied, to address and exceed the envisioned potential for visual analytics technologies. We start with a brief summary of the initial challenges, followed by a discussion of the initial driving domains and applications, as well as additional applications and domains that have been a part of recent rapid expansion of visual analytics usage. We look at the common characteristics of several tools illustrating emerging visual analytics technologies, and conclude with the top ten challenges for the field of study. We encourage feedback and collaborative participation by members of the research community, the wide array of user communities, and private industry.

  16. Analytical Instrument Obsolescence Examined.

    ERIC Educational Resources Information Center

    Haggin, Joseph

    1982-01-01

    The threat of instrument obsolescence and tight federal budgets have conspired to threaten the existence of research analytical laboratories. Despite these and other handicaps most existing laboratories expect to keep operating in support of basic research, though there may be serious penalties in the future unless funds are forthcoming. (Author)

  17. Analytical Services Management System

    SciTech Connect

    Church, Shane; Nigbor, Mike; Hillman, Daniel

    2005-03-30

    Analytical Services Management System (ASMS) provides sample management services. Sample management includes sample planning for analytical requests, sample tracking for shipping and receiving by the laboratory, receipt of the analytical data deliverable, processing the deliverable and payment of the laboratory conducting the analyses. ASMS is a web based application that provides the ability to manage these activities at multiple locations for different customers. ASMS provides for the assignment of single to multiple samples for standard chemical and radiochemical analyses. ASMS is a flexible system which allows the users to request analyses by line item code. Line item codes are selected based on the Basic Ordering Agreement (BOA) format for contracting with participating laboratories. ASMS also allows contracting with non-BOA laboratories using a similar line item code contracting format for their services. ASMS allows sample and analysis tracking from sample planning and collection in the field through sample shipment, laboratory sample receipt, laboratory analysis and submittal of the requested analyses, electronic data transfer, and payment of the laboratories for the completed analyses. The software when in operation contains business sensitive material that is used as a principal portion of the Kaiser Analytical Management Services business model. The software version provided is the most recent version, however the copy of the application does not contain business sensitive data from the associated Oracle tables such as contract information or price per line item code.

  18. Ada & the Analytical Engine.

    ERIC Educational Resources Information Center

    Freeman, Elisabeth

    1996-01-01

    Presents a brief history of Ada Byron King, Countess of Lovelace, focusing on her primary role in the development of the Analytical Engine--the world's first computer. Describes the Ada Project (TAP), a centralized World Wide Web site that serves as a clearinghouse for information related to women in computing, and provides a Web address for…

  19. Model-independent measurement of S-wave K-π+ systems using D+→Kππ decays from Fermilab E791

    NASA Astrophysics Data System (ADS)

    Aitala, E. M.; Amato, S.; Anjos, J. C.; Appel, J. A.; Ashery, D.; Banerjee, S.; Bediaga, I.; Blaylock, G.; Bracker, S. B.; Burchat, P. R.; Burnstein, R. A.; Carter, T.; Carvalho, H. S.; Copty, N. K.; Cremaldi, L. M.; Darling, C.; Denisenko, K.; Devmal, S.; Fernandez, A.; Fox, G. F.; Gagnon, P.; Gobel, C.; Gounder, K.; Halling, A. M.; Herrera, G.; Hurvits, G.; James, C.; Kasper, P. A.; Kwan, S.; Langs, D. C.; Leslie, J.; Lundberg, B.; Magnin, J.; Massafferri, A.; Maytal-Beck, S.; Meadows, B.; Neto, J. R. T. De Mello; Mihalcea, D.; Milburn, R. H.; de Miranda, J. M.; Napier, A.; Nguyen, A.; D'Oliveira, A. B.; O'Shaughnessy, K.; Peng, K. C.; Perera, L. P.; Purohit, M. V.; Quinn, B.; Radeztsky, S.; Rafatian, A.; Reay, N. W.; Reidy, J. J.; Dos Reis, A. C.; Rubin, H. A.; Sanders, D. A.; Santha, A. K. S.; Santoro, A. F. S.; Schwartz, A. J.; Sheaff, M.; Sidwell, R. A.; Slaughter, A. J.; Sokoloff, M. D.; Solano, J.; Stanton, N. R.; Stefanski, R. J.; Stenson, K.; Summers, D. J.; Takach, S.; Thorne, K.; Tripathi, A. K.; Watanabe, S.; Weiss-Babai, R.; Wiener, J.; Witchey, N.; Wolin, E.; Yang, S. M.; Yi, D.; Yoshida, S.; Zaliznyak, R.; Zhang, C.; Dunwoodie, W. M.

    2006-02-01

    A model-independent partial-wave analysis of the S-wave component of the Kπ system from decays of D+ mesons to the three-body K-π+π+ final state is described. Data come from the Fermilab E791 experiment. Amplitude measurements are made independently for ranges of K-π+ invariant mass, and results are obtained below 825MeV/c2, where previous measurements exist only in two mass bins. This method of parametrizing a three-body decay amplitude represents a new approach to analyzing such decays. Though no model is required for the S-wave, a parametrization of the relatively well-known reference P- and D-waves, optimized to describe the data used, is required. In this paper, a Breit-Wigner model is adopted to describe the resonances in these waves. The observed phase variation for the S-, P-, and D-waves do not match existing measurements of I=(1)/(2) K-π+ scattering in the invariant mass range in which scattering is predominantly elastic. If the data are mostly I=(1)/(2), this observation indicates that the Watson theorem, which requires these phases to have the same dependence on invariant mass, may not apply to these decays without allowing for some interaction with the other pion. The production rate of K-π+ from these decays, if assumed to be predominantly I=(1)/(2), is also found to have a significant dependence on invariant mass in the region above 1.25GeV/c2. These measurements can provide a relatively model-free basis for future attempts to determine which strange scalar amplitudes contribute to the decays.

  20. Measurement of Rayleigh wave ellipticity and its application to the joint inversion of high-resolution S wave velocity structure beneath northeast China

    NASA Astrophysics Data System (ADS)

    Li, Guoliang; Chen, Haichao; Niu, Fenglin; Guo, Zhen; Yang, Yingjie; Xie, Jun

    2016-02-01

    We present a new 3-D S wave velocity model of the northeast (NE) China from the joint inversion of the Rayleigh wave ellipticity and phase velocity at 8-40 s periods. Rayleigh wave ellipticity, or Rayleigh wave Z/H (vertical to horizontal) amplitude ratio, is extracted from both earthquake (10-40 s) and ambient noise data (8-25 s) recorded by the NorthEast China Extended SeiSmic Array with 127 stations. The estimated Z/H ratios from earthquake and ambient noise data show good consistency within the overlapped periods. The observed Z/H ratio shows a good spatial correlation with surface geology and is systematically low within the basins. We jointly invert the measured Z/H ratio and phase velocity dispersion data to obtain a refined 3-D S wave velocity model beneath the NE China. At shallow depth, the 3-D model is featured by strong low-velocity anomalies that are spatially well correlated with the Songliao, Sanjiang, and Erlian basins. The low-velocity anomaly beneath the Songliao basin extends to ~ 2-3 km deep in the south and ~5-6 km in the north. At lower crustal depths, we find a significant low-velocity anomaly beneath the Great Xing'an range that extends to the upper mantle in the south. Overall, the deep structures of the 3-D model are consistent with previous models, but the shallow structures show a much better spatial correlation with tectonic terranes. The difference in sedimentary structure between the southern and northern Songliao basin is likely caused by a mantle upwelling associated with the Pacific subduction.

  1. Mantle Composition and Temperature of Western North America Revealed from Direct P and S Wave Velocities of KLB-1 Peridotite to the Condition of Transition Zone

    NASA Astrophysics Data System (ADS)

    Wang, X.; Chen, T.; Qi, X.; Zou, Y.; Liebermann, R. C.; Li, B.

    2015-12-01

    Comparing the elasticity of candidate compositional models with seismic profiles (e.g., PREM and AK135) is one of the most important geophysical approaches to constrain the mineralogical composition of the mantle. However in such averaging schemes (e.g., Voigt-Reuss-Hill), it is difficult to take into account all of the mineralogical and chemical complexities; we therefore undertook elasticity study of a natural mantle rock sample at high pressures and temperatures. In this study, a series of polycrystalline aggregates of peridotite KLB-1 (from Kilbourne Hole, New Mexico) were hot-pressed at pressures of 3-15 GPa and temperatures of 1200-1400°C. Scanning electron microscopy (SEM), Electron Microprobe Analysis (EPMA) and X-ray diffraction (XRD) were used to characterize the texture, grain size, and composition of these well-sintered specimens. For the first time in history, the P and S wave velocities of a pyrolitic multiphase aggregate were directly measured at mantle transition zone pressures and temperatures using ultrasonic interferometry. Based on the phase fractions from EPMA and the P and S wave velocities from in situ measurement at high pressure and high temperature, the velocities of the KLB-1 peridotite along 1200-1400 oC adiabatic mantle geotherms were obtained and compare well with the seismic models of western North America, the region where these peridotite KLB-1 samples were collected. The comparison with regional seismic models of western North America (e.g., GCA and TNA/TNA2) as well as global seismic models (PREM and AK135) place unprecedented constraints on the composition, temperature and density profiles for the upper mantle in this region, which can help us understand the nature of thermal and tectonic processes of the Rio Grande Rift.

  2. Requirements for Predictive Analytics

    SciTech Connect

    Troy Hiltbrand

    2012-03-01

    It is important to have a clear understanding of how traditional Business Intelligence (BI) and analytics are different and how they fit together in optimizing organizational decision making. With tradition BI, activities are focused primarily on providing context to enhance a known set of information through aggregation, data cleansing and delivery mechanisms. As these organizations mature their BI ecosystems, they achieve a clearer picture of the key performance indicators signaling the relative health of their operations. Organizations that embark on activities surrounding predictive analytics and data mining go beyond simply presenting the data in a manner that will allow decisions makers to have a complete context around the information. These organizations generate models based on known information and then apply other organizational data against these models to reveal unknown information.

  3. Nuclear analytical chemistry

    SciTech Connect

    Brune, D.; Forkman, B.; Persson, B.

    1984-01-01

    This book covers the general theories and techniques of nuclear chemical analysis, directed at applications in analytical chemistry, nuclear medicine, radiophysics, agriculture, environmental sciences, geological exploration, industrial process control, etc. The main principles of nuclear physics and nuclear detection on which the analysis is based are briefly outlined. An attempt is made to emphasise the fundamentals of activation analysis, detection and activation methods, as well as their applications. The book provides guidance in analytical chemistry, agriculture, environmental and biomedical sciences, etc. The contents include: the nuclear periodic system; nuclear decay; nuclear reactions; nuclear radiation sources; interaction of radiation with matter; principles of radiation detectors; nuclear electronics; statistical methods and spectral analysis; methods of radiation detection; neutron activation analysis; charged particle activation analysis; photon activation analysis; sample preparation and chemical separation; nuclear chemical analysis in biological and medical research; the use of nuclear chemical analysis in the field of criminology; nuclear chemical analysis in environmental sciences, geology and mineral exploration; and radiation protection.

  4. Analytical caustic surfaces

    NASA Technical Reports Server (NTRS)

    Schmidt, R. F.

    1987-01-01

    This document discusses the determination of caustic surfaces in terms of rays, reflectors, and wavefronts. Analytical caustics are obtained as a family of lines, a set of points, and several types of equations for geometries encountered in optics and microwave applications. Standard methods of differential geometry are applied under different approaches: directly to reflector surfaces, and alternatively, to wavefronts, to obtain analytical caustics of two sheets or branches. Gauss/Seidel aberrations are introduced into the wavefront approach, forcing the retention of all three coefficients of both the first- and the second-fundamental forms of differential geometry. An existing method for obtaining caustic surfaces through exploitation of the singularities in flux density is examined, and several constant-intensity contour maps are developed using only the intrinsic Gaussian, mean, and normal curvatures of the reflector. Numerous references are provided for extending the material of the present document to the morphologies of caustics and their associated diffraction patterns.

  5. Analytic holographic superconductor

    NASA Astrophysics Data System (ADS)

    Herzog, Christopher P.

    2010-06-01

    We investigate a holographic superconductor that admits an analytic treatment near the phase transition. In the dual 3+1-dimensional field theory, the phase transition occurs when a scalar operator of scaling dimension two gets a vacuum expectation value. We calculate current-current correlation functions along with the speed of second sound near the critical temperature. We also make some remarks about critical exponents. An analytic treatment is possible because an underlying Heun equation describing the zero mode of the phase transition has a polynomial solution. Amusingly, the treatment here may generalize for an order parameter with any integer spin, and we propose a Lagrangian for a spin-two holographic superconductor.

  6. Avatars in Analytical Gaming

    SciTech Connect

    Cowell, Andrew J.; Cowell, Amanda K.

    2009-08-29

    This paper discusses the design and use of anthropomorphic computer characters as nonplayer characters (NPC’s) within analytical games. These new environments allow avatars to play a central role in supporting training and education goals instead of planning the supporting cast role. This new ‘science’ of gaming, driven by high-powered but inexpensive computers, dedicated graphics processors and realistic game engines, enables game developers to create learning and training opportunities on par with expensive real-world training scenarios. However, there needs to be care and attention placed on how avatars are represented and thus perceived. A taxonomy of non-verbal behavior is presented and its application to analytical gaming discussed.

  7. Competing on analytics.

    PubMed

    Davenport, Thomas H

    2006-01-01

    We all know the power of the killer app. It's not just a support tool; it's a strategic weapon. Companies questing for killer apps generally focus all their firepower on the one area that promises to create the greatest competitive advantage. But a new breed of organization has upped the stakes: Amazon, Harrah's, Capital One, and the Boston Red Sox have all dominated their fields by deploying industrial-strength analytics across a wide variety of activities. At a time when firms in many industries offer similar products and use comparable technologies, business processes are among the few remaining points of differentiation--and analytics competitors wring every last drop of value from those processes. Employees hired for their expertise with numbers or trained to recognize their importance are armed with the best evidence and the best quantitative tools. As a result, they make the best decisions. In companies that compete on analytics, senior executives make it clear--from the top down--that analytics is central to strategy. Such organizations launch multiple initiatives involving complex data and statistical analysis, and quantitative activity is managed atthe enterprise (not departmental) level. In this article, professor Thomas H. Davenport lays out the characteristics and practices of these statistical masters and describes some of the very substantial changes other companies must undergo in order to compete on quantitative turf. As one would expect, the transformation requires a significant investment in technology, the accumulation of massive stores of data, and the formulation of company-wide strategies for managing the data. But, at least as important, it also requires executives' vocal, unswerving commitment and willingness to change the way employees think, work, and are treated. PMID:16447373

  8. Industrial Analytics Corporation

    SciTech Connect

    Industrial Analytics Corporation

    2004-01-30

    The lost foam casting process is sensitive to the properties of the EPS patterns used for the casting operation. In this project Industrial Analytics Corporation (IAC) has developed a new low voltage x-ray instrument for x-ray radiography of very low mass EPS patterns. IAC has also developed a transmitted visible light method for characterizing the properties of EPS patterns. The systems developed are also applicable to other low density materials including graphite foams.

  9. Competing on talent analytics.

    PubMed

    Davenport, Thomas H; Harris, Jeanne; Shapiro, Jeremy

    2010-10-01

    Do investments in your employees actually affect workforce performance? Who are your top performers? How can you empower and motivate other employees to excel? Leading-edge companies such as Google, Best Buy, Procter & Gamble, and Sysco use sophisticated data-collection technology and analysis to answer these questions, leveraging a range of analytics to improve the way they attract and retain talent, connect their employee data to business performance, differentiate themselves from competitors, and more. The authors present the six key ways in which companies track, analyze, and use data about their people-ranging from a simple baseline of metrics to monitor the organization's overall health to custom modeling for predicting future head count depending on various "what if" scenarios. They go on to show that companies competing on talent analytics manage data and technology at an enterprise level, support what analytical leaders do, choose realistic targets for analysis, and hire analysts with strong interpersonal skills as well as broad expertise. PMID:20929194

  10. Raman-Scattering Measurements and Theory of the Energy-Momentum Spectrum for Underdoped Bi2Sr2CaCuO8+δ Superconductors: Evidence of an s-Wave Structure for the Pseudogap

    NASA Astrophysics Data System (ADS)

    Sakai, S.; Blanc, S.; Civelli, M.; Gallais, Y.; Cazayous, M.; Méasson, M.-A.; Wen, J. S.; Xu, Z. J.; Gu, G. D.; Sangiovanni, G.; Motome, Y.; Held, K.; Sacuto, A.; Georges, A.; Imada, M.

    2013-09-01

    We reveal the full energy-momentum structure of the pseudogap of underdoped high-Tc cuprate superconductors. Our combined theoretical and experimental analysis explains the spectral-weight suppression observed in the B2g Raman response at finite energies in terms of a pseudogap appearing in the single-electron excitation spectra above the Fermi level in the nodal direction of momentum space. This result suggests an s-wave pseudogap (which never closes in the energy-momentum space), distinct from the d-wave superconducting gap. Recent tunneling and photoemission experiments on underdoped cuprates also find a natural explanation within the s-wave pseudogap scenario.