In order to obtain a realistic description of the propagation of sound over long distances in the atmosphere or in the ocean, or to compute the paths deep in the earth followed by earthquake waves, one must take into account the continuous variations in properties of the atmosphere, the ocean, or the earth. With these and other applications in mind, authors have published dozens of articles on wave propagation in inho-mogeneous media, and a chapter is devoted to this subject in each of two recent books. [1, 2]. Attention has been focused exclusively on situations where velocity varies from point to point, and techniques for computing curved ray paths have been developed quite fully. It is the purpose of this paper to examine the case where density and elastic constants vary in direct proportion, so that the propagation velocity is constant throughout the medium. An interest in the propagation of elastic waves in a thin wedge led to this study, and the relation between a thin wedge and a linearly inhomogeneous medium is discussed.
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Seismic Wave Propagation: Collected Works of J. E. White
This first chapter sets the stage for the later technical development of Dr. Whit’s career in applied seismics. Experiments, f’wst at the Acoustics Laboratory of the Massachusetts Institute of Technology and later at Mobil Oil and Marathon Oil, provided insight into the general problems of impedance measurements, transduction, filtering, and attenuation. These papers also serve as a bridge to show geophysicists how theft own experiments in seismology naturally interface with (indeed, arose out of) the larger world of sound measurements in air and water. These experiments demonstrate the power of geometrically constrained experiments to allow verification of approximate (and in some cases, exact) theories of sound.