Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Influence Of Scattering On Seismic Waves Velocity And Attenuation Of The Upper Crust In Southeast Maine
Download Influence Of Scattering On Seismic Waves Velocity And Attenuation Of The Upper Crust In Southeast Maine full books in PDF, epub, and Kindle. Read online Influence Of Scattering On Seismic Waves Velocity And Attenuation Of The Upper Crust In Southeast Maine ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Influence of Scattering on Seismic Waves: Velocity and Attenuation of the Upper Crust in Southeast Maine by : Edmund Reister
Download or read book Influence of Scattering on Seismic Waves: Velocity and Attenuation of the Upper Crust in Southeast Maine written by Edmund Reister and published by . This book was released on 1988 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rg and Pg velocities and Rg attenuation have been examined for the Central Merrimack Synclinorium and nearby regions in southeastern Maine using digital records from a seismic refraction experiment. Determination of Rg group velocities and Pg travel times indicates that both lateral variations and azimuthal anisotropy are present in the study area. The axes of the axes of the azimuthal velocity anisotropy appear to lie along and perpendicular to the Appalachian structural strike in the region, with Rg group velocities along strike up to 20% faster than cross strike velocities. Measurement of Rg attenuation gives Q values of 25-80, varying with frequency. Inversion of the Rg group velocity for velocity structure shows that both the compressional and shear velocities increase rapidly with depth in the upper 1 km in the region. Keywords: Short period Rayleigh waves, Anisotropy, Earth crustal structure, Seismic wave attenuation, New England. (edc).
Book Synopsis Influence of Scattering on Seismic Waves by : Edmund Reiter
Download or read book Influence of Scattering on Seismic Waves written by Edmund Reiter and published by . This book was released on 1988 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1989 with total page 984 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scattering and Attenuations of Seismic Waves, Part I by : AKI
Download or read book Scattering and Attenuations of Seismic Waves, Part I written by AKI and published by Birkhäuser. This book was released on 2013-12-18 with total page 443 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reprint from Pure and Applied Geophysics (PAGEOPH), Volume 128 (1988), No. 1/2
Book Synopsis Scattering and Attenuation of Seismic Waves, Part II by : WU
Download or read book Scattering and Attenuation of Seismic Waves, Part II written by WU and published by Birkhäuser. This book was released on 2013-11-21 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reprint from Pure and Applied Geophysics (PAGEOPH), Volume 131 (1989), No. 4
Book Synopsis Influence of Scattering on Seismic Waves by : M. N. Toksöz
Download or read book Influence of Scattering on Seismic Waves written by M. N. Toksöz and published by . This book was released on 1988 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Work on this contract examined two subjects, the analysis of seismic data using the NORESS array in southern Norway and the attenuation properties of the crust. This document consists of two preprints. The first, 'Phase velocity estimation of diffusely scattered waves deals with work at NORESS which was partly carried out under a previous contract, partly in conjunction with the Lawrence Livermore National Laboratory and partly under this contract. The second paper, 'A model for attenuation and scattering in the earth's crust', describes work on attenuation. Keywords: Coda waves; Seismic array analysis; Phase velocity; Rayleigh waves. (EDC).
Book Synopsis Scattering and Attenuation of Seismic Waves by : Keiiti Aki
Download or read book Scattering and Attenuation of Seismic Waves written by Keiiti Aki and published by Birkhauser. This book was released on 1988 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Government Reports Announcements & Index by :
Download or read book Government Reports Announcements & Index written by and published by . This book was released on 1992-12 with total page 2022 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Bibliography of North American Geology by :
Download or read book Bibliography of North American Geology written by and published by . This book was released on 1965 with total page 1162 pages. Available in PDF, EPUB and Kindle. Book excerpt: 1919/28 cumulation includes material previously issued in the 1919/20-1935/36 issues and also material not published separately for 1927/28. 1929/39 cumulation includes material previously issued in the 1929/30-1935/36 issues and also material for 1937-39 not published separately.
Download or read book Geological Survey Bulletin written by and published by . This book was released on 1949 with total page 1306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Influence of Scattering on Seismic Waves: Physical Mechanisms Contributing to Attenuation in the Crust by : M. N. Toksoez
Download or read book Influence of Scattering on Seismic Waves: Physical Mechanisms Contributing to Attenuation in the Crust written by M. N. Toksoez and published by . This book was released on 1987 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanisms contributing to the attenuation of earthquake ground motion in the distance range of 10 to 200 km are studied with the aid of laboratory data, coda waves and strong motion attenuation measurements in the northeastern United States and Canada and theoretical models. The relative contributions to attenuation of anelasticity of crustal rocks (constant Q), fluid flow and scattering are evaluated. Scattering is found to be strong with albedo of Bo - 0.9 and scattering extinction length of about 17 km. The intrinsic attenuation in the crust can be explained by a high constant Q (500
Book Synopsis Government Reports Annual Index by :
Download or read book Government Reports Annual Index written by and published by . This book was released on 1989 with total page 1672 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Changes in Seismic Velocity and Apparent Attenuation Due to Isotropic and Anisotropic Scattering by : Bruce H. Dubendorff
Download or read book Changes in Seismic Velocity and Apparent Attenuation Due to Isotropic and Anisotropic Scattering written by Bruce H. Dubendorff and published by . This book was released on 1987 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Much work is presently being done concerning small scale heterogeneities in the earth's crust. These heterogeneities range from pores in sedimentary rocks up to fluctuations in the density and seismic constants of the earth's crust with scale lengths of kilometers. The ability to study and quantify these heterogeneities using seismic methods would be a major advance in the earth sciences. Physical modeling has been shown to be a useful technique for investigating various aspects of wave propagation. In this thesis, two physical modeling experiments (one three-dimensional and one two-dimensional) are used to investigate the scattering of seismic waves from small scale heterogeneities and the changes in seismic velocity and apparent attenuation resulting from this scattering. The effects of both isotropic and anisotropic scattering on velocity and apparent attenuation are calculated. These experimental results are compared to theoretical results. The theory used for isotropic scattering for the three-dimensional experiment is a modified version of Wu's single scattering theory, where instead of calculating the scattering for a single scatterer using the Born approximation, the exact results for scattering from a cylindrical shape are used. While the results for compressional waves and both components of shear waves compare reasonably well for small scatterer volume fractions, at larger scatterer volume fractions, where the need for multiple scattering is more likely, the results for all waves do not compare as well. Many theories used to test anisotropic scattering predict changes in velocity rather than changes in apparent attenuation. The velocity changes are used primarily in this work due to geometrical focusing by a seismic lens that biases the amplitudes (and hence the estimates of apparent attenuation) at low frequencies where most theories predict apparent attenuation. Velocities are calculated from the data using travel times and low frequency phase shifts for the compressional waves and for one component of the shear waves measured in this two-dimensional experiment. Theories that are used to predict compressional and shear wave velocities for both isotropic and anisotropic scatterers are based on a fractional volume method (isotropic), two crack methods (isotropic and anisotropic), and a finely layered method (anisotropic). The isotropic experimental results have much larger, non-linear changes in the velocities than do the isotropic theoretical results. The anisotropic experimental results have similar shapes to both theoretical anisotropic methods for compressional waves and to the theoretical anisotropic crack method for shear waves. Attenuation is computed using log spectral ratios and compares as well with the theoretical results as can be expected within the limits set. A method using anisotropic apparent attenuation to help quantify the scatterers is developed for use with field data.
Download or read book Geological Abstracts written by and published by . This book was released on 1988 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Collection and Analysis of Seismic-wave Propagation Data by :
Download or read book Collection and Analysis of Seismic-wave Propagation Data written by and published by . This book was released on 1968 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report discusses the results of an extensive long-range reversed refraction profile which traverses the Michigan Basin and the Appalachian Mountains. Particular emphasis is placed on the attenuation of first compressional wave arrivals and on crustal-upper mantle structure. Also included are results of a survey on lake bottom seismic background noise in Lake Superior. Although large signal levels were obtained in the lake bottom, long periods of high background noise indicated that land based seismographs are superior. Theoretical studies in elastic wave scattering were made to evaluate the effect of nonhomogeneities on the propagation of elastic waves. Theoretical development of mode filtering (previously demonstrated empirically), is nearly completed. A LASA digital data convertor was designed, constructed, and put into operation. Two- and three-dimensional seismic ray-tracing techniques using digital modeling were developed. These techniques enable the seismologist to determine the effects of lateral inhomogeneities and irregularities in velocity interfaces on travel time and attenuation of seismic waves. (Author).
Book Synopsis Ocean Bottom Seismic Scattering by : Martin Eugene Dougherty
Download or read book Ocean Bottom Seismic Scattering written by Martin Eugene Dougherty and published by . This book was released on 1989 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic studies of the oceanic crust, both experimental and theoretical, often assume a flat seafloor and laterally homogeneous crust. This is done regardless of the appearance in seismic data of obvious effects due to scattering from lateral heterogeneities both on and in the seafloor. Detailed fine scale surveys of mid-ocean ridges, where the upper oceanic crust is exposed, have revealed the presence of lateral heterogeneities in the form of complicated topography, extrusive volcanic structure, and abundant fracturing and faulting. These heterogeneities have a significant affect on the propagation of seismo/acoustic energy through the crust, especially in the immediate vicinity of the seafloor. This thesis deals with the problem of scattering of seismo/acoustic energy from a number of forms of lateral heterogeneity in the upper oceanic crust. A common theme throughout this work is that the size of the heterogeneity on or in the seafloor is of the same order of magnitude as the seismo/acoustic wavelength. This is the realm of scattering theory where the wave-like characteristics of seismic energy have a particularly large influence on the outcome of interaction with structure in the media. The work presented here involves the application of the finite difference modeling technique to problems concerning laterally heterogeneous elastic media. This method is a full wave solution to the elastic wave equation and as such includes all wave interactions with the media. The finite difference formulation is used to study four distinct phenomena; scattering from discrete deterministic seafloor features; wave propagation through continuous randomly heterogeneous upper oceanic crust; scattering from more complicated topographic profiles and the limitations of the method for the rough seafloor problem; and the problem of plane acoustic wave scattering from an infinite elastic cylinder. The principal finding of this work is that lateral heterogeneities in the upper oceanic crust can have a dramatic affect on seismo/acoustic wave propagation. Scattering from rough seafloors and/or volume heterogeneities is often quite similar and causes the occurrence of signal generated 'noise' (coda), decorrelation of primary arrivals, and anomalies in arrival travel time and amplitude. Topographic and volume scatterers acting as secondary sources of seismic energy can cause a resonant coupling of body wave energy into interface (Stoneley) waves at the seafloor. This is possibly one mechanism by which natural seismic and storm generated acoustic energy can be coupled into seafloor noise. The applicability of the use of the finite difference method for non-planar water-solid interfaces is also discussed. Models were calculated which approximate sinusoidal seafloors and plane acoustic wave scattering from an infinite elastic cylinder. The discretization of a rectangular difference grid must be extremely fine to accurately accommodate a smoothly varying water-solid interface which does not align with the grid. Regardless of the discretization concerns, the rough seafloor models presented here demonstrate the arrivals expected from larger scale sinusoidal topography as well as the importance of considering quite small (
Book Synopsis Scattering Attenuation in Fractally Homogeneous Random Media by : C. Reese
Download or read book Scattering Attenuation in Fractally Homogeneous Random Media written by C. Reese and published by . This book was released on 1995 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Much of seismic nuclear monitoring depends on a proper understanding of attenuation and scattering of regional seismic waves. This report seeks to characterize wave scattering from both an observational and theoretical approach. A theory of wave propagation in fractally homogeneous random media is developed and applied to southern Tibet in order to quantify the analytical and statistical properties of crust and upper lithosphere heterogeneity. Seismic velocity heterogeneity is modeled by a self-affine band limited random fractal. An approximation to multiple scattering theory yields a relationship between the exponent of the frequency dependent scattering quality factor Q and the fractal dimension of velocity iso-surfaces. In this study, the attenuation quality factor of P-waves, Qp, is calculated for southern Tibet and the implications for the fractal dimension of the velocity field are discussed. In addition, the topic of intermittent heterogeneity is introduced. The generalization of the model to fractally homogeneous media implies that scattering attenuation measurements are characterized by two fractal dimensions: one related to the self-affinity of the velocity field and the other related to the metric of the space which the field occupies. Within a fractal random media model, the attenuation calculation for southern Tibet yields a fractal dimension of velocity iso-surfaces of D = 9/4 which implies the existence of complex large-scale structure in the upper lithosphere.
