Azimuthally-dependent P-wave AVO (amplitude variation with offset) responses can be related to open fracture orientation and have been suggested as a geophysical tool to identify fracture orientation in fractured oil and gas reservoirs. A field experiment recently conducted over a fractured reservoir in the Barinas Basin (Venezuela) provides data for an excellent test of this approach. Three li...

Observations are presented of nonlinear internal waves on the outer New England continental shelf during the summer Shelfbreak Primer study conducted between July 26 and August 5, 1996. Current and temperature measurements were made with an upward looking acoustic Doppler current profiler (ADCP) located on the 147 m isobath near the shelfbreak and three vertical thermistor moorings located upsh...

the mixture of natural and artificial seismic sources with random distributions cause diffuse wave field with random amplitudes and phases called noise. when noise is analyzed in a long-term process, it contains surface waves which are spread in all directions. thus, ambient noise contains data relevant to the surface waves. in recent years, as broadband seismic networks have been distributed v...

Profiles of SH waves diffracted around the core (Sd) for three deep events at stations across North America and the Atlantic (4 = 92 ° to 152 °) are used to determine the properties of the lower mantle in the vicinity of the core-manUe boundary (CMB). The S-wave velocity above the CMB is found to be tic = 7.22 __ 0.1 km/sec, in agreement with gross earth models, but higher than previously repor...

recently, the s receiver function method has been successfully developed to identify upper mantle interfaces. s receiver functions have the advantage of being free of s-wave multiple reflections and can be more suitable than p receiver function for studying mantle lithosphere. however, because of specific ray geometry of the s-to-p converted waves, the s receiver function method has some techni...

the aim of this research is recognizing synoptic patterns of the level 500 hp occurrence of late spring freezes over kurdistan province during 1965-2005. after determining freeze temporal-spatial threshold, 22 freezing days spreading over the region were extracted. then, level 500 hp height data located in a scope of 25-60 northern latitude and 30-60 eastern longitude was formulated as an s-mod...

In this paper, we are interested with the spectral study of an operator given by an elastic topographical waveguide, a deformed half-space, of which the cross-section is a local perturbation of a homogeneous half-plane. We look for guided waves propagating more rapidly than Rayleigh waves (which mathematically would correspond to embedded eigenvalues) and prove that there are no guided waves pr...

Recently we studied the effects of information carrying waves propagating through isotropic cosmologies. By information carrying we mean that the waves have an arbitrary dependence on a function. We found that the waves introduce shear and anisotropic stress into the universe. We then constructed explicit examples of pure gravity wave perturbations for which the presence of this anisotropic str...

This paper considers properties of nonlinear waves and solitons of Korteweg-de Vries equation in the presence of external perturbation. Basing on a method of stochastic destruction of separatrix, we obtain the criterion for stochasticity for such the waves. It shows that under any excitation nonlinear waves and solitons acquire the property of stirring and thereby become stochastically unstable...

in partial fulfillment of the requirements for the degree of Doctor of Philosophy ABSTRACT Observational work by Thompson (1977) and others has demonstrated that free topographic Rossby waves propaqate northward up the continental rise south of New England. To study the dynamical implications of these waves as they approach the shelf, Beardsley, Vermersch, and Brown conducted an experiment in 1...