Bottom-Interacting Ocean Acoustics

ISBN-13: 9781468490534 / Angielski / Miękka / 2012 / 717 str.

Opis

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.

Spis treści

Geoacoustic Properties of Marine Sediments.- Attenuation of Sound in Marine Sediments.- Directivity and Radiation Impedance of a Transducer Embedded in a Lossy Medium.- Elastic Properties Related to Depth of Burial, Strontium Content and Age, and Diagenetic Stage in Pelagic Carbonate Sediments.- Application of Geophysical Methods and Equipment to Explore the Sea Bottom.- The Acoustic Response of Some Gas-Charged Sediments in the Northern Adriatic Sea.- Simultaneous Application of Reflection Strength Recorder, Sidescan Sonar and Sub-Bottom Profiler in Sea-Floor Sediment Mapping.- Results and Methods Used to Determine the Acoustic Properties of the Southeast Asian Margins.- Circular Structures Observed in the Deep Sea by the Swathmap Long-Range Sidescan Sonar.- Bottom Loss: Reflection and Refraction.- A Perspective on Bottom Reflectivity and Backscattering.- Some Bottom-Reflection Loss Anomalies Near Grazing and their Effect on Propagation in Shallow Water.- Determination of Sediment Sound Speed Profiles Using Caustic Range Information.- Inference of Geo-Acoustic Parameters from Bottom-Loss Data.- Attenuation Estimates from High Resolution Sub-Bottom Profiler Echoes.- Low Frequency Bottom Reflectivity Measurements in the Tufts Abyssal Plain.- Resonances in Acoustic Bottom Reflection and their Relation to the Ocean Bottom Properties.- Comparison of Synthetic and Experimental Bottom Interactive Waveforms.- Reflection and Refraction of Parametrically Generated Sound at a Water-Sediment Interface.- Transmission of a Narrow Beam of Sound across the Boundary between two Fluids.- Bottom-Interface and Seismic-Wave Propagation.- Experimental Determination of Properties of the Scholte Wave in the Bottom of the North Sea.- Model Computations for Low-Velocity Surface Waves on Marine Sediments.- Experimental and Theoretical Studies of Seismic Interface Waves in Coastal Waters.- Ambient and Ship-Induced Low-Frequency Noise in Shallow Water.- Dispersion of One-Second Rayleigh Modes through Oceanic Sediments Following Shallow Earthquakes in the South-Central Pacific Ocean Basin.- Velocity Spectral Estimates from the Arrays of the ROSE Program.- Acoustic Modelling.- Bottom Interaction Represented by Impedance Conditions in Normal-Mode Calculations.- Cycle Distance in Guided Propagation.- Computations of Averaged Sound-Propagation Losses and Frequency/Space Coherence Functions in Shallow Waters.- Initial Data for the Parabolic Equation.- The Seamount as a Diffracting Body.- Propagation of Sound from a Fluid Wedge into a Fast Fluid Bottom.- Range-Dependent Bottom-Limited Propagation Modelling with the Parabolic Equation.- Sound Propagation: Techniques and Experiment vs Theory.- A Low-Frequency Parametric Research Tool for Ocean Acoustics.- Transmission Loss Variability in Shallow Water.- Influence of Semiconsolidated Sediments on Sound Propagation in a Coastal Region.- Geoacoustic Models of the Seabed to Support Range-Dependent Propagation Studies on the Scotian Shelf.- Propagation Loss Modelling on the Scotian Shelf: the Geo-Acoustic Model.- Propagation Loss Modelling on the Scotian Shelf: Comparison of Model Predictions with Measurements.- Sea Floor Effects on Shallow-Water Acoustic Propagation.- Broadband Model/Data Comparisons for Acoustic Propagation in Coastal Waters.- Computer Model Predictions of Ocean Basin Reverberation for Large Underwater Explosions.- Fluctuations, Coherence and Signal Processing.- Fluctuation Statistics of Sea-Bed Acoustic Backscatter.- Measurements of Spatial Coherence of Bottom-Interacting Sound in the Tagus Abyssal Plain.- Effects of Medium Fluctuations on Underwater Acoustic Transmissions in a Shallow Water Area.- Analysis of Time-Varying Spatially-Varying Sound-Propagation Systems.- Phase-Coherence in a Shallow Water Waveguide.- The Influence of Unknown Bottom Parameters on Bearing Estimation in Shallow Water.- List of contributors.- Author Index.