Download or read book Regional Seismic Wave Propagation written by Paul W. Pomeroy and published by . This book was released on 1979 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research reported here was carried out to enhance our understanding of seismic wave propagation at regional distances in the central portion of the USSR. Results in this region are contrasted with those from the Western USSR and with data from eastern North America.

Download or read book Regional Characterization of the Seismic Wave Propagation of Central Eurasia Using Deterministic Crustal Models written by Thomas Scott Anderson and published by . This book was released on 1997 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modes Rays and Scattering A Basic Study of Seismic Wave Propagation at Regional Distances written by and published by . This book was released on 1997 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research was to systematically explore the attributes of the wave form Lg and related wave forms which are trapped in the crust. The different theoretical approximations used to characterize or to fully compute regional seismic waves were thoroughly investigated. Empirical classification of the behavior of Lg was achieved through waveform data analyses. The Kennett conjecture that Lg waves can be adequately described by multiple S energy trapped in the crust has been adopted. It has been shown that Lg magnitudes are much more stable than the chaotic behavior of the ray would seem to imply. As a result of recognizing that a large number of caustic are generated as a consequence of the chaotic ray behavior, it was decided that Maslov theory was probably the only suitable technique to deal with the singularity problem. As a result, it has been shown that Maslov synthetics can be used to justify the use of ray density plots as energy plots, which can be used in turn for the calibration of Lg magnitudes. The 3-component array and single station data from the NPE 1993 detonation have been analyzed in order to examine the effects boundary undulations of the crustal wave guide may have on propagation.

Download or read book Seismic Wave Propagation in Stratified Media written by Brian Kennett and published by ANU E Press. This book was released on 2009-05-01 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic Wave Propagation in Stratified Media presents a systematic treatment of the interaction of seismic waves with Earth structure. The theoretical development is physically based and is closely tied to the nature of the seismograms observed across a wide range of distance scales - from a few kilometres as in shallow reflection work for geophysical prospecting, to many thousands of kilometres for major earthquakes. A unified framework is presented for all classes of seismic phenomena, for both body waves and surface waves. Since its first publication in 1983 this book has been an important resource for understanding the way in which seismic waves can be understood in terms of reflection and transmission properties of Earth models, and how complete theoretical seismograms can be calculated. The methods allow the development of specific approximations that allow concentration on different seismic arrivals and hence provide a direct tie to seismic observations.

Download or read book Fundamentals of Seismic Wave Propagation written by Chris Chapman and published by Cambridge University Press. This book was released on 2004-07-29 with total page 646 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Seismic Wave Propagation, published in 2004, presents a comprehensive introduction to the propagation of high-frequency body-waves in elastodynamics. The theory of seismic wave propagation in acoustic, elastic and anisotropic media is developed to allow seismic waves to be modelled in complex, realistic three-dimensional Earth models. This book provides a consistent and thorough development of modelling methods widely used in elastic wave propagation ranging from the whole Earth, through regional and crustal seismology, exploration seismics to borehole seismics, sonics and ultrasonics. Particular emphasis is placed on developing a consistent notation and approach throughout, which highlights similarities and allows more complicated methods and extensions to be developed without difficulty. This book is intended as a text for graduate courses in theoretical seismology, and as a reference for all academic and industrial seismologists using numerical modelling methods. Exercises and suggestions for further reading are included in each chapter.

Download or read book Regional Seismic Wave Propagation written by J. A. Carter and published by . This book was released on 1984 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: Work has involved evaluation of method for using regional seismic waves, particularly Lg for yield determination. The Wake Island Hydrophone Array digital recording continues to provide high quality data. Polarization and array analyses have been made of Catskill Seismic Array and Regional Seismic Test Network data. For continental models, whole waveform synthetics demonstrate clearly the large dependence of the amplitude and spectral shape on the focal depth and the smaller dependence of these factors on focal mechanism. The broadband digital seismic station, SRNY has been in operation since 16 May 1984. Digital data are recorded magnetic cartridge tapes each capable of holding 67 Megabytes or 38 hours of data. Many programs have been developed for data handling and analysis. Keywords include: Pn and Sn, Yield determination, and Depth discrimination.

Download or read book A Study of Seismic Wave Propagation at Regional Distances in Five Areas of the World written by Z. A. Der and published by . This book was released on 1982 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Propagation and excitation of regional phases in southern Africa, the southwestern United States, the Pakistan-India region, South America, and the Kamchatka-Kuriles region were studied. Comparison of the shield areas of South America, Pakistan and southern Africa reveals no appreciable differences in the excitation and attenuation of regional phases in these areas. On the other hand, excitation and attenuation rates for all regional phases are markedly different in the southwestern United States. The mountainous areas of South America are characterized by highly variable propagation characteristics, with Sn and Lg being absent from many seismograms studied. Attenuation of Sn and Lg is especially severe along the southern Andes mountains in Chile and Argentina. For these areas, the value of regional phases for detection and discrimination is highly questionable. The Andes region is also characterized by highly unusual seismograms with scattered, emergent phases resembling lunar seismograms. These problems are present, though to a much lesser degree, in the mountainous areas surrounding India and Pakistan. These areas are also characterized by highly variable propagation efficiency and by spatial attenuation that is higher than that of the shield.

Download or read book Seismic Wave Propagation and Scattering in the Heterogenous Earth written by Haruo Sato and published by Springer Science & Business Media. This book was released on 2008-12-17 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic waves – generated both by natural earthquakes and by man-made sources – have produced an enormous amount of information about the Earth's interior. In classical seismology, the Earth is modeled as a sequence of uniform horizontal layers (or sperical shells) having different elastic properties and one determines these properties from travel times and dispersion of seismic waves. The Earth, however, is not made of horizontally uniform layers, and classic seismic methods can take large-scale inhomogeneities into account. Smaller-scale irregularities, on the other hand, require other methods. Observations of continuous wave trains that follow classic direct S waves, known as coda waves, have shown that there are heterogeneities of random size scattered randomly throughout the layers of the classic seismic model. This book focuses on recent developments in the area of seismic wave propagation and scattering through the randomly heterogeneous structure of the Earth, with emphasis on the lithosphere. The presentation combines information from many sources to present a coherent introduction to the theory of scattering in acoustic and elastic materials and includes analyses of observations using the theoretical methods developed.

Download or read book The Seismic Wavefield Volume 1 Introduction and Theoretical Development written by B. L. N. Kennett and published by Cambridge University Press. This book was released on 2001-11-12 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a guide to understanding of seismograms for graduate students, researchers, professionals in academia and the petroleum industry.

Download or read book The Effects of Seismic Anisotropy on Regional Seismic Wave Propagation written by and published by . This book was released on 1997 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crustal rocks can be highly anisotropic, due to (1) oriented minerals, (2) oriented cracks, and/or (3) thin layers of material with different elastic stiffnesses. Crustal Love and Rayleigh surface waves couple strongly for anisotropic structures that do not possess a vertical axis of symmetry, and cause explosions to generate significant shear motion on the transverse component of seismograms. We developed theory and 1-D layered-media synthetic seismogram codes for anisotropy with an arbitrary axis of symmetry. One code version can synthesize surface waves with periods 100 > T > 0.4 sec. Another code version can synthesize teleseismic body wave reverberations up to 5 Hz. We determined that a tilted axis of symmetry enhances Love-Rayleigh coupling and the scattering of P-waves (compressional) to S-waves (shear). Using P-S scattering, we found evidence for strong (> 10%) anisotropy in the deepest and shallowest crustal layers beneath seismic station ARU (Arti, Russia), an 'open' seismic observatory proximal to the Novaya Zemlya nuclear test site. We also developed a wavelet-based signal processing algorithm that picks out correlated 'signals' from uncorrelated 'noise' in an optimally bandpassed manner. Using the Terrascope regional array in California we applied this algorithm to reconstruct, for a single correlated signal anomalous amplitudes and polarizations at individual stations, allowing more 'signal' to be recovered than via standard 'stacking.'

Download or read book Collection and Analysis of Seismic Wave Propagation Data written by David E. Willis and published by . This book was released on 1966 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report summarizes one year of theoretical and applied research on propagation of seismic waves and techniques for analyzing data. The main objectives were to determine the frequency and energy of seismic signatures, and investigate attenuation, patterns of azimuthal radiation from source regions, and methods of determining the type of motion at the source. Natural and artificial sources were studied to develop diagnostic aids for distinguishing between earthquakes and underground nuclear detonations. Equipment for selection, reformatting, and digital-to-analog conversion for digitally recorded LASA data was constructed and is being checked out. Several approaches for using the parallel computational capabilities of optics for LASA data were developed. A study of background noise and reciprocity for teleseismic events as recorded on the bottom of a large fresh water lake has commenced with the emplacement of three-component seismometers in Lake Superior. Array data have been used for crustal studies on the Eastern United States. Digital mode filtering was investigated. A perturbation theory for seismic sources was developed. (Author).

Download or read book The Seismic Wavefield Volume 2 Interpretation of Seismograms on Regional and Global Scales written by B. L. N. Kennett and published by Cambridge University Press. This book was released on 2001 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Guide to understanding of seismograms for graduate students, researchers, professionals in academia and petroleum industry.

Download or read book An Integrated Study of Lithospheric Structure Regional Seismic Wave Propagation and Seismic Discrimination Capability in the Middle East written by Keith Priestley and published by . This book was released on 1996 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report covers a number of studies relevant to seismic verification of the CTBT in Asia. The south Caspian basin anomalously affects regional seismic wave. Mangino and Priestley (1998) use teleseismic receiver functions and deep seismic sounding data to determine a crustal model of the basin and the surrounding region. Priestley, Patton and Schultz (1998) use this crustal structure to model the anomalous surface wave propagation across the basin seen in data from the Caspian Seismic Network. The attenuation of the intermediate frequency surface waves is primarily affected by the thick, low Q sediments. Cipar and Priestley (1997) have used reflectivity modeling of seismograms from three nuclear explosions along the RIFT profile to form a quasi-2-D cross section of the crust and upper mantle structure beneath the Siberian platform.

Download or read book An Investigation of Seismic Wave Propagation in Eastern North America written by P. W. Pomeroy and published by . This book was released on 1978 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic waves propagated and recorded at regional distances in eastern North America are being studies for possible use in discriminating between explosion and earthquake sources. This report deals with (a) the propagation characteristics of the regional seismic wave designated L sub g and (b) an evaluation of the usefulness of a particular ocean bottom seismograph system as an aid in discrimination of seismic sources at regional distances. Results of the study of the propagation characteristics of L sub g, with predominant frequencies of 1-3 hertz, is consistently the largest amplitude portion of the short period signal from the Eastern North American events studied. Analysis of the group velocity for each event studied shows a clustering of measurements in the 3.47 km/sec range for the earthquakes studied and a significantly lower 3.24 km/sec mean for measurements from the SALMON explosion. This lower value is believed to be the result of propagation path or source effects. When group velocity information was divided into two regions, E (h)--high group velocity (4.0-3.4 km/sec) energy--and E(l)--low group velocity (3.4-2.8 km/sec) energy, the ratios of these areas showed a discrimination between SALMON ((E(h)/E(l) .5) and the earthquakes ((E(h)/E(l).5). Phase velocity measurements made using records from Cumberland Plateau Seismic Observatory have a mean of 4.18 km/sec. Analysis of a second event also yields measurements in the 4.0-4.4 km/sec range.

Download or read book Global Investigation of Seismic Wave Propagation on a Regional Scale written by Jack E. Oliver and published by . This book was released on 1981 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Th Middle East study is focused on the Turkish and Iranian plateaus and the surrounding regions. Sn amplitude variations are very striking in these areas. Efficient Sn propagation is observed across a major part of the Turkish and Iranian plateaus. However, Sn is strongly attenuated in the northernmost part of the plateaus south of the Black and Caspian Seas, and in the area between these two areas. These regions are characterized, in general, by active tectonism, including volcanism, faulting, and folding. However, this active tectonism is not restricted to the areas of high Sn attenuation, but appears to extend, though with somewhat less apparent activity, beneath a major part of the Turkish and Iranian plateaus. Patterns of lateral variations in the propagation of Lg are not as consistent as those for Sn. Lg propagates efficiently across Turkey, Iran and adjacent regions, but the Lg waves that cross the Turkish and Iranian plateaus are, in general, weak and have relatively long predominant periods of about 2-5 seconds. The Lg phase is not observed when the path of propagation crosses the southern Caspian and the Black Seas, consistent with the available evidence of oceanic-type crustal structure beneath these seas. (Author).

Download or read book Seismic Wave Propagation and Scattering in the Heterogeneous Earth Second Edition written by Haruo Sato and published by Springer Science & Business Media. This book was released on 2012-03-08 with total page 505 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic waves - generated both by natural earthquakes and by man-made sources - have produced an enormous amount of information about the Earth's interior. In classical seismology, the Earth is modeled as a sequence of uniform horizontal layers (or spherical shells) having different elastic properties and one determines these properties from travel times and dispersion of seismic waves. The Earth, however, is not made of horizontally uniform layers, and classic seismic methods can take large-scale inhomogeneities into account. Smaller-scale irregularities, on the other hand, require other methods. Observations of continuous wave trains that follow classic direct S waves, known as coda waves, have shown that there are heterogeneities of random size scattered randomly throughout the layers of the classic seismic model. This book focuses on recent developments in the area of seismic wave propagation and scattering through the randomly heterogeneous structure of the Earth, with emphasis on the lithosphere. The presentation combines information from many sources to present a coherent introduction to the theory of scattering in acoustic and elastic materials and includes analyses of observations using the theoretical methods developed. The second edition especially includes new observational facts such as the spatial variation of medium inhomogeneities and the temporal change in scattering characteristics and recent theoretical developments in the envelope synthesis in random media for the last ten years. Mathematics is thoroughly rewritten for improving the readability. Written for advanced undergraduates or beginning graduate students of geophysics or planetary sciences, this book should also be of interest to civil engineers, seismologists, acoustical engineers, and others interested in wave propagation through inhomogeneous elastic media.

Download or read book Effects of Small Scale Heterogeneities on Regional Propagation written by Stanley M. Flatte and published by . This book was released on 1990 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Regional seismic-wave propagation at frequencies above 1 Hz is described in terms of ray theory, and the effects of small-scale heterogeneities are described statistically by means of the modern theory of wave propagation through random media. Observed features of regional propagation, such as the complexity of waveforms over tens or hundreds of seconds, the sensitivity of this complexity to the location of source or receiver, and the spread in arrival angles of waves at a receiving array, are explained by this propagation model. Keywords: Propagation; Heterogeneities; Seismic waves; Crustal waveguide. (jhd).