The radiation patterns of an elastic wave field generated by circular plane compressional and shear transducers are derived using the method of steepest descent. These patterns contain both effects of the elastic half space and the amplitude modulation due to the finite dimension of the piston source. Behaviors of radiation patterns of the generated compressional and shear waves are shown for l...

Multicomponent seismic images are composed of different combinations of downgoing and upgoing wavefields. Each wave mode has different propagation velocity and polarization direction and thus carries unique, direction-dependent information about the subsurface. Differences in propagation velocity cause events in convertedor shear-wave images to appear at later times than the compressional-wave ...

We present high-resolution compressional wave to shear wave velocity ratios (Vp∕Vs) beneath Kı̄lauea’s summit caldera by applying an in situ estimation method using waveform cross-correlation data for three similar earthquake clusters. We observe high Vp∕Vs ratios (1.832 and 1.852) for two event clusters surrounded by the low background Vp∕Vs value of 1.412 at ∼2.1 km depth below the surface. Th...

Recently, Morner discussed his model of glacio-isostatic compensation in the light of new seismological models of the upper mantle below Fennoscandia (Miimer, 1990). He concluded that the P-wave velocity distribution is in “full agreement” with his estimate of the viscosity distribution as inferred from glacio-isostatic relaxation. Whereas the consistency of seismological and geodynamical earth...

A vertical seismic profiling (VSP) method was developed to produce compressional (p-wave) velocity sections in a 3-D survey volume, down to a maximum depth of 57 m. The VSP method consisted of a multilevel hydrophone tool deployed down several wells. Multiple offset surface shotpoints were recorded at multiple azimuths around each well head, using an impact source. The VSP data were processed a...

According to a recently developed theory of wave propagation in marine sediments, the dispersion relationships for the phase speed and attenuation of the compressional and the shear wave depend on only three macroscopic physical variables: porosity, grain size, and depth in the sediment. The dispersion relations also involve three (real) parameters, assigned fixed values, representing microscop...

We have measured elastic (bulk and shear modulus) and acoustic (compressional and shear wave velocities) properties of heavy-oil sands over a range of frequencies (2− 2000Hz) covering the seismic bandwidth and at ultrasonic frequencies (0.8MHz). The measurements were carried on heavy-oil sand sample from Asphalt Ridge, Utah at a constant temperature ( 20oC) and different confining pressures usi...

The time harmonic Green function for a point load in an unbounded fluid-saturated porous solid is derived in the context of Biot's theory. The solution contains the two compressional waves and one transverse wave that are predicted by the theory and have been observed in experiments. At low frequency, the slow compressional wave is diffusive and only the fast compressional nd transverse waves r...

Introduction During hydraulic fracturing experiments in the laboratory the opening of hydraulic fractures is monitored with ultrasonic transducers. The experiment closely resembles seismic monitoring surveys in the field [MEADOWS AND WINTERSTEIN 1994, WILLS ET AL. 1992]. The extraction of information out of these experiments is critically dependent on the understanding of the elastodynamic beha...

ultrasonic testing (ut), a nondestructive testing (ndt) method, is under development for quality determination of agricultural products, although it has long been used in the food industry. determination and measurement of product quality are important in modern agricultural research. noninvasive/nondestructive quality determination is a novel aspect of the postharvest process in which paramete...