a r t i c l e i n f o a b s t r a c t Improving the reliability and accuracy in the determination of the depth to velocity discontinuities in the Earth's mantle is essential for a better understanding of mantle dynamics, as well as for addressing such fundamental questions as the origin of mantle plumes and fate of subducted slabs. Most existing techniques that utilize receiver function stackin...

To date, a number of numerical methods, including the popular Finite-Difference Time Domain (FDTD) technique, have been proposed to simulate Ground-Penetrating Radar (GPR) responses. Despite having a number of advantages, the finite-difference method also has pitfalls such as being very time consuming in simulating the most common case of media with high dielectric permittivity, causing the for...

Abstract In the field of complex underground geological structures and irregular topography, prestack seismic data often have a low Signal-to-Noise Ratio (SNR), where weakly reflected signals are buried beneath strong incoherent, scattered noise. Stacking, such as beamforming along moveout surfaces coherent local events, can significantly improve quality. Accurate efficient estimation for an ac...

We show that diffraction stack migration can be used to estimate the distribution of near-surface faults. The assumption is that near-surface faults generate detectable back-scattered surface waves from impinging surface waves. The processing steps are to isolate the back-scattered surface waves, and then migrate them by diffraction migration using the surface wave velocity as the migration vel...

Three multiple attenuation techniques are tested on a Gulf of Mexico dataset. These methods are (1) a hyperbolic Radon transform followed by a mute (2), the Delft approach and (3), a pattern-based technique. The Radon transform separates multiples and primaries according to their moveout. The Delft approach models the multiples and subtracts them by estimating adaptive filters. The pattern-base...

in this paper a first step in classifying the fuzzy normalsubgroups of a finite group is made. explicit formulas for thenumber of distinct fuzzy normal subgroups are obtained in theparticular cases of symmetric groups and dihedral groups.