Download or read book Acoustic and Related Properties of the Sea Floor Shear Wave Velocity Profiles and Gradients written by Edwin L. Hamilton and published by . This book was released on 1975 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of the velocity of shear waves at various depths in common watersaturated sediments were collected from published studies. Because measurements in marine sediments are rare, most of this information came from land geology and geophysics. This report considered the two end-member sediments types: sand and silt-clays, including turbidites which are alternating layers of silt-clay with thinner layers of silt and sand. The shear velocity measurements in sands were 29 selected, in situ values at depths to 12m. Data from laboratory and field studies indicate that shear wave velocity is proportional to the 1/3 to 1/6 power of pressure or depth in sands; that the 1/6 power is not reached until very high pressures are applied; and that for most sand bodies the exponent is between 3/10 and 1/4. Data from laboratory studies allow prediction of compressional wave (sound) as a function of depth in sands. The shear velocity measurements in silt-clays and turbidites used in this report include 47 measurements to depths of 650 m. Three linear equations were used to characterize the data. The shear velocity gradient in the upper 40m(4.65/sec) is 4-5 times greater than is the compressional wave (sound) velocity gradient in comparable sediments. At deeper depths, shear velocity and compressional velocity gradients are comparable. This report concludes with methods for prediction of shear wave velocity profiles and gradients in sea-floor sediments. This result will be of immediate use in a sophisticated model that determines sound energy losses when an acoustic wave interacts with the sea floor.
Download or read book Acoustic and Related Properties of the Sea Floor written by Edwin Lee Hamilton and published by . This book was released on 1975 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The general objectives of this investigation were to determine and study those characteristics of the sea floor that affect sound propagation and the prediction of sonar performance; to support underwater acoustics' experiments and theory by furnishing information on the mass physical properties of sediments and rocks in the form of geoacoustic models of the sea floor; and to develop models of the sea floor which include gradients of sound velocity and attenuation, density, and elastic properties. Specifically, the minor objectives were to revise and review earlier work on the relations between frequency and attenuation of compressional (sound) waves in marine sediments and on the relations between attenuation and sediment porosity. The major objectives were to determine and predict variations of the attenuation of sound waves with depth in the sea floor.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1990 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acoustic and Related Properties of the Sea Floor Density and Porosity Profiles and Gradients written by Edwin L. Hamilton and published by . This book was released on 1975 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: The general objectives of this investigation were (1) to determine and study those characteristics of the sea floor that affect the propagation of sound and the prediction of sonar performance; (2) to support underwater acoustic experiments and theory by furnishing information on the mass physical properties of sediments and rocks in the form of geoacoustic models of the sea floor; and (3) to develop models of the sea floor which include gradients of sound velocity and attenuation, density, and elastic properties. The specific objectives of this particular report were to determine and predict density profiles and gradients in common sediment and rock layers of the sea floor.
Download or read book Ocean Seismo Acoustics written by T. Akal and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 898 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seafloor investigation has long been a feature of not only seismology but also of acoustics. Indeed it was acoustics that produced depth sounders, giving us the first capability of producing both global and local maps of the seafloor. Subsequently, better instrumentation and techniques led to a clearer, more quantitative picture of the seabed itself, which stimulated new hypotheses such as seafloor spreading through the availability of more reliable data on sediment thickness over ocean basins and other bottom features. Geologists and geophysicists have used both acoustic and seismic methods to study the seabed by considering the propagation of signals arising from both natural seismic events and man-made impulsive sources. Although significant advances have been made in instrumentation, such as long towed geophysical arrays, ai r guns and ocean bot tom seismometers, the pic ture of the seafloor is still far from complete. Underwater acoustics concerns itself today with the phenomena of propagation and noise at frequencies and ranges that require an understanding of acoustic interaction at both of its boundaries, the sea surface and seafloor, over depths ranging from tens to thousands of meters. Much of the earlier higher frequency (>1 kHz) work included the characterization of the seafloor in regimes of reflection coefficients which were empirically derived from surveys. The results of these studies met with only limited success, confined as they were to those areas where survey data existed and lacking a physical understanding of the processes of reflection and scattering.
Download or read book Bottom Interacting Ocean Acoustics written by William A. Kuperman and published by Springer Science & Business Media. This book was released on 2013-03-13 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: vi These categories seem to represent the basic breakdown by field of present-day research in this area. Though each paper has been classified into one of these categories (for conference organization purpose), many papers overlapped two or three areas. It is also interesting to note that not only are scientific results being communicated, but the latest techniques and the state-of-the-art tools of the trade (existing and in development) are also being presented. The forty-six papers presented at this conference represent the work of seventy scientists working at universities, government laboratories, and industrial laboratories in seven different countries . We would like to thank the contributors for their efforts and especially for their promptness in providing the editors with their final manuscripts. William A. Kuperman Finn B. Jensen La Spezia, Italy July 1980 CONTENTS GEOACOUSTIC PROPERTIES OF MARINE SEDIMENTS Attenuation of Sound in Marine Sediments . • 1 J. M. Hovem Directivity and Radiation Impedance of a Transducer 15 Embedded in a Lossy Medium . •• •••••• G. H. Ziehm Elastic Properties Related to Depth of Burial, Strontium Content and Age, and Diagenetic Stage in Pelagic Carbonate Sediments . . • • . • • • . 41 M. H. Manghnani, S. O. Schianger, and P. D. Milholland Application of Geophysical Methods 'and Equipment to Explore the Sea Bottom . •• •••. • 53 H. F. Weichart The Acoustic Response of Some Gas-Charged Sediments in the Northern Adriatic Sea • • • • . • • • • 73 A.
Download or read book High Frequency Seafloor Acoustics written by Darrell Jackson and published by Springer Science & Business Media. This book was released on 2007-08-02 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a research monograph on high-Frequency Seafloor Acoustics. It is the first book in a new series sponsored by the Office of Naval Research on the latest research in underwater acoustics. It provides a critical evaluation of the data and models pertaining to high-frequency acoustic interaction with the seafloor, which will be of interest to researchers in underwater acoustics and to developers of sonars. Models and data are presented so as to be readily usable, backed up by extensive explanation. Much of the data is new, and the discussion in on two levels: concise descriptions in the main text backed up by extensive technical appendices.
Download or read book Government Reports Annual Index written by and published by . This book was released on 1975 with total page 882 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oceanic Acoustic Modelling Sea bottom written by and published by . This book was released on 1975 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics of Sound in Marine Sediments written by Lloyd Hampton and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: The phenomenon of sound transmissions through marine sediments is of extreme interest to both the United States civilian and Navy research communities. Both communities have conducted research within the field of this phenomenon approaching it from different perspectives. The academic research community has approached it as a technique for studying sedimentary and crustal structures of the ocean basins. The Navy research community has approached it as an additional variable in the predictability of sound trans mission through oceanic waters. In order to join these diverse talents, with the principal aim of bringing into sharp focus the state-of-the-science in the problems relating to the behavior of sound in marine sediments, the Office of Naval Research organized and sponsored an invited symposium on this subject. The papers published in this volume are the results of this symposium and mark the frontiers in the state-of-the-art. The symposia series were based on five research areas identified by ONR as being particularly suitable for critical review and for the appraisal of future research trends. These areas include: 1. Physics of Sound in Marine Sediments, 2. Physical and Engineering Properties of Deep-Sea Sediments, 3. The Role of Bottom Currents in Sea Floor Geological Processes, 4. Nephelometry and the Optical Properties of the Ocean I'laters, S. Natural Gases in Marine Sediments and Their Mode of Distribution. These five areas also form some of the research priorities of the ONR program in Marine Geology and Geophysics.
Download or read book Interaction of Sound with the Ocean Bottom written by and published by . This book was released on 1978 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report documents the results of a three-year study of the interaction of sound with the sea floor. The investigation covered sea floor properties of interest in underwater acoustics, including velocity gradients in the sea floor, density, shear-wave velocities and other properties; research on acoustic propagation models, especially at low frequencies (2 to 200 Hz); and the development of accurate and efficient methods for coupling geoacoustic models to standard propagation models such as ray theory, normal mode theory and P.E. (a numerical method using the Parabolic Equation approximation to the wave equation). During this period numerous reports were distributed to the acoustic community. Various predictions for the surveillance community have been calculated using the geoacoustic and acoustic models, support was provided to others developing models and support was provided on a continuous basis to surveillance programs including the Indian Ocean, MSS, SURTASS, and others. An extensive list of references is included. (Author).
Download or read book Acoustics of the Seabed as a Poroelastic Medium written by Nicholas P. Chotiros and published by Springer. This book was released on 2017-03-20 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a concise description of the acoustics of ocean sediment acoustics, including the latest developments that address the discrepancies between theoretical models and experimental measurements. This work should be of interest to ocean acoustic engineers and physicists, as well as graduate students and course instructors. The seabed is neither a liquid nor a solid, but a fluid saturated porous material that obeys the wave equations of a poroelastic medium, which are significantly more complicated than the equations of either a liquid or a solid. This volume presents a model of seabed acoustics with input parameters that allow the model to cover a wide range of sediment types. The author includes example reflection and transmission curves which may be used as typical for a range of sediment types. The contents of this book will allow the reader to understand the physical processes involved in the reflection, propagation, and attenuation of sound and shear waves in ocean sediments and to model the acoustic properties for a wide range of applications.
Download or read book Shear speed Gradients and Ocean Seismo acoustic Noise Resonances written by and published by . This book was released on 1999 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents experimental evidence of a seabed resonance phenomenon involving shear waves in surficial sediments for which the theoretical explanation depends critically on the shear-speed gradient. The paper also proposes a wave-theoretical model for the phenomenon. Section I presents experimental data showing seafloor noise resonances and a description of the environment. Section II relates the noise resonances to normal modes of vertically polarized shear waves and indicates the parameters of the problem that allow its analytical consideration. Section III analyzes the normal modes at normal incidence to determine resonance frequencies. An exact solution for shear wave normal modes in a layer with power-law profile of rigidity is obtained & analyzed in section IV. Effects of deviations from the power law are then addressed and some computational results are provided in section VI to illustrate some of the analytically derived conclusions. The final section examines the interplay of the various model parameters, notably the profile of shear speed versus sediment depth.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1974 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Underwater Acoustic Modeling and Simulation Fifth Edition written by Paul C. Etter and published by CRC Press. This book was released on 2018-03-15 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt: This newest edition adds new material to all chapters, especially in mathematical propagation models and special applications and inverse techniques. It has updated environmental-acoustic data in companion tables and core summary tables with the latest underwater acoustic propagation, noise, reverberation, and sonar performance models. Additionally, the text discusses new applications including underwater acoustic networks and channel models, marine-hydrokinetic energy devices, and simulation of anthropogenic sound sources. It further includes instructive case studies to demonstrate applications in sonar simulation.
Download or read book Proceedings of the Ocean Drilling Program written by Ocean Drilling Program and published by . This book was released on 1987 with total page 808 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Petroleum Abstracts written by and published by . This book was released on 1993 with total page 1752 pages. Available in PDF, EPUB and Kindle. Book excerpt:
