Multi-channel Analysis of Surface Waves (MASW) is a suitable technique for vertical shear-wave velocity profile determination whose efficiency and effectiveness depends on data acquisition parameters and processing procedures. In the present paper we compare the performances of three different methods to determine Rayleigh waves dispersion curves. Such curves are successively exploited for the ...

In the classic microseismic band of 5-20 s seismic noise consists mainly of fundamental mode Rayleigh and Love waves; however, at shorter periods seismic noise also contains a significant amount of body wave energy and higher-mode surface waves. In this study we perform a global survey of Earth’s short period seismic noise field with the goal of quantifying the relative contributions of these p...

In the present study, dispersion and displacement curves of ultrasonic lamb wave, propagated in Aluminum thin plates, were drawn. Two ultrasonic lamb wave techniques, pulse-echo (a1 mode as emitter) and emission (s1 mode as emitter), were used for interpretation of notch defects with depths of 10%, 30% and 60% of plate thickness. Thickness of plate was 2 mm and the nominal centre frequency of t...

Ambient noise tomography has proven to be effective in resolving shallow earth structure. We applied ambient noise tomography on a dense seismic array in Long Beach, California. The array was composed of more than 5200 stations with an average spacing close to 100 m. Three weeks of passive ambient noise were crosscorrelated between each station pair, which resulted in more than 13.5 million cro...

Modal dispersion data i.e. mode travel time as a function of frequency have been used in inversion schemes that estimate sediment properties in a range-independent environment. This method has been extended to include range-dependent environment. Simulation studies show that range-dependent sediment properties can be extracted if mode dispersion data are obtained for multiple source/receiver lo...

The linear Rayleigh–Taylor instability of two immiscible superposed non-Newtonian fluids saturated by a porous medium in the simultaneous presence interfacial surface tension and suspended dust particles is investigated. behavior described Jeffrey model. set coupled partial differential equations satisfying appropriate boundary conditions solved applying theory normal mode technique. exact solu...

Data transmission in optical systems and increased transmission distance capacity benefit by using optical amplification wavelength division multiplexing (WDM) technology. The combination of four waves (FWM) is a non-linear effect in the wavelength division multiplex (WDM), when more than two wavelengths of light in a fiber launch will occur. FWM amount depends on the channel, the channel spaci...

The governing equations of a transversely isotropic dissipative medium are solved analytically to obtain the surface wave solutions. The appropriate solutions satisfy the required boundary conditions at the stress-free surface to obtain the frequency equation of Rayleigh wave. The numerical values of the non-dimensional speed of Rayleigh wave speed are computed for different values of frequency...