Interfering elastic wave components
Abstract
In a homogeneous isotropic elastic medium plane waves can be propagated with the velocities a = square root of (lambda + 2 mu)/rho and b = square root of mu/rho, where mu, rho and rho are Lame parameters and density; the first corresponds to longitudinal polarization and the second to transverse polarization. The ray method makes it possible to construct a highfrequency analogue of a plane wave in a smoothly inhomogeneous medium. Highfrequency perturbations, traveling with the velocities a(x) and b(x), are polarized primarily the same as in a homogeneous medium, but also have weaker components, transverse and longitudinal, called interfering components. However, the formulas for these components have been unwieldy. In order to simplify this problem the author has derived and discusses more convenient formulas for the interfering components of nonstationary modulated oscillations. In the discussion it is made clear that the relative role of the interfering components is determined but also by the kinematics and dynamics of the problem (the geometry of the rays and the diagrams of the sources). The interfering components have a lower frequency. These interfering components of longitudinal and transverse waves in certain cases should be significant in seismic investigations.
 Publication:

USSR Report Earth Sciences JPRS UES
 Pub Date:
 July 1984
 Bibcode:
 1984RpESc.......60K
 Keywords:

 Low Frequencies;
 Perturbation;
 Plane Waves;
 Polarization Characteristics;
 Oscillations;
 Seismic Waves;
 Seismology