The information and technology necessary to derive a valid geological-geophysical-acoustic model of the sea floor are presented. Two contrasting models are detailed and discussed: one in the Bering Sea which has a shallow-water, high-velocity, hard-sand bottom; and the Mohole (Guadalupe Site) model which has a deep-water, low-velocity, soft-clay bottom. Other models are to be reported in a continuing series. (Author).
This two-volume handbook presents advanced research and operational information about hard minerals and hydrocarbons. It provides information in an integrated, interdisciplinary manner, stressing case histories. It includes review chapters, illustrations, graphs, tables, and color satellite images that present the results of gravity, geodetic, and seismic surveys and of 3-D sea floor sub-bottom visualizations. The data was obtained using satellites, aircraft, and ships from the Atlantic and Pacific Oceans, the Gulf of Mexico, and the Caribbean Sea. Major topics addressed in these volumes include geophysical methods used to explore for hydrocarbons, advanced radiometric and electrical methods for hard mineral searches, the role of geotechnology and seismic acoustics in overcoming geological hazards in selecting drilling sites and pipeline routes, and remote sensing techniques used to determine the physical properties of sediments.
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
Underwater Acoustic Modeling provides the only comprehensive source on how to translate our physical understanding of sound in the sea into mathematical formulas solvable by computers.
This book discusses in depth many of the key problems in non-equilibrium physics. The origin of macroscopic irreversible behavior receives particular attention and is illustrated in the framework of solvable models. An updated discussion on the linear response focuses on the correct electrodynamic aspects, which are essential for example, in the proof of the Nyquist theorem. The material covers the scaling relationship between different levels of description (kinetic to hydrodynamic) as well as spontaneous symmetry breaking in real time in terms of nonlinear dynamics (attractors), illustrated using the example of Bose-Einstein condensation. The presentation also includes the latest developments - quantum kinetics - related to modern ultrafast spectroscopy, where transition from reversible to irreversible behavior occurs.
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.
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.
Underwater Acoustic Modeling and Simulation, Fourth Edition continues to provide the most authoritative overview of currently available propagation, noise, reverberation, and sonar-performance models. This fourth edition of a bestseller discusses the fundamental processes involved in simulating the performance of underwater acoustic systems and emphasizes the importance of applying the proper modeling resources to simulate the behavior of sound in virtual ocean environments. New to the Fourth Edition Extensive new material that addresses recent advances in inverse techniques and marine-mammal protection Problem sets in each chapter Updated and expanded inventories of available models Designed for readers with an understanding of underwater acoustics but who are unfamiliar with the various aspects of modeling, the book includes sufficient mathematical derivations to demonstrate model formulations and provides guidelines for selecting and using the models. Examples of each type of model illustrate model formulations, model assumptions, and algorithm efficiency. Simulation case studies are also included to demonstrate practical applications. Providing a thorough source of information on modeling resources, this book examines the translation of our physical understanding of sound in the sea into mathematical models that simulate acoustic propagation, noise, and reverberation in the ocean. The text shows how these models are used to predict and diagnose the performance of complex sonar systems operating in the undersea environment.
This text features 105 papers dealing with the fundamentals and the applications of poromechanics from the Biot conference of 1998, held in Louvain-la-Neuve. Topics include: wave propogation; numerical modelling; identification of poromechanical parameters; and constitutive modelling.
