Shear wave splitting of SK(K)S phases is often used to examine upper mantle anisotropy. In specific cases, however, splitting of these phases may reflect anisotropy in the lowermost mantle. Here we present SKS and SKKS splitting measurements for 233 event-station pairs at 34 seismic stations that sample D′′ beneath Africa. Of these, 36 pairs show significantly different splitting between the tw...

Rayleigh-wave phase velocity of a layered earth model is a function of frequency and four groups of earth properties: Pwave velocity, S-wave velocity (Vs), density, and thickness of layers. Analysis of the Jacobian matrix (or the difference method) provides a measure of dispersion curve sensitivity to earth properties. Vs is the dominant influence for the fundamental mode (Xia et al., 1999) and...

The elastic properties of the unconsolidated materials which cover most of the earth are, in general, unknown. In this paper, an attempt was made to measure, in the field, the shear and compressional wave velocities, with the emphasis on those for shear waves. For this purpose,'a simple source was devised which produced fairly pure shear waves. A portable refraction seismograph of standard desi...

The dynamics of amphiphilic films deposited on a solid surface is analyzed for the case when shear oscillations of the solid surface are excited. The two cases of surface-and bulk shear waves are studied with the film exposed to gas or to a liquid. By solving the corresponding dispersion equation and the wave equation while maintaining the energy balance we are able to connect the surface densi...

[1] We apply seismic interferometry to strong-motion records to detect the near-surface (i.e., an upper few hundred meters deep) change in anisotropy caused by the MW 9.0 Tohoku-Oki earthquake on 11 March 2011. We show that the earthquake increased the difference between fast and slow shear-wave velocities arising from shear-wave splitting in most parts of northeastern Japan, but it did not sig...

Within the crust, the weathered layer has been shown to contain some of the greatest values of shear wave velocity anisotropy. There are two main causes of this shear wave velocity anisotropy. In all rock types, anisotropy results from structural weaknesses commonly manifest as aligned open fractures. In sedimentary rocks, additional anisotropy can result from mineral or grain particle alignmen...

The hydrodynamic modes and the velocity autocorrelation functions for a dilute sheared inelastic fluid are analyzed using an expansion in the parameter =(1-e);{12} , where e is the coefficient of restitution. It is shown that the hydrodynamic modes for a sheared inelastic fluid are very different from those for an elastic fluid in the long-wave limit, since energy is not a conserved variable wh...

A time domain method is presented for analyzing simultaneous measurements of pressure and the horizontal components of velocity obtained beneath irregular multidirectional wave fields. This new method differs from the usual linear directional analyses applied to PUV data in two important aspects. First, the essential nonlinearity of the measured waves is not sacrificed to achieve a solution. Th...

In this paper, propagation of shear waves in a non-homogeneous anisotropic incompressible, magnetic field, gravity field and initially stressed medium has been studied. Analytical analysis reveals that the velocity of propagation of the shear waves depends upon the direction of propagation, the anisotropy, magnetic field, gravity field, non-homogeneity of the medium, and the initial stress. The...