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Efcient mixed domain pure P wave equations for 2D and 3D tilted transversely isotropic media

Li Bowen, Wang Deli, Zhou Jinju, Zhang Qianxiang, Wang Rui

Acta Geophysica

2020

Vol. 68, no. 3

605--618

In transversely isotropic (TI) media, accurate and efcient pure P-wave extrapolation is the basis of seismic imaging and inversion algorithms. For pure P-wave equations in TI media, combining the fnite-diference (FD) method with the pseudospectral (PS) method is an efective solution. However, if the mixed-domain pure P-wave equation contains multiple wavenumbers, using the hybrid approach will involve multiple Fourier transforms, which will result in high computational costs. Referring to the weak anisotropy approximation, we propose a new approximate P-wave phase velocity expression. We then use an optimization strategy to reduce the number of wavenumber terms in the corresponding dispersion relations and derive the mixed-domain pure P-wave equations in 2D and 3D tilted transversely isotropic (TTI) media. Through numerical experiments in 2D and 3D TTI models, we verify the feasibility and efciency of the proposed mixed-domain P-wave equations.

Reaction of plane waves from a rotating magneto-thermoelastic medium with two-temperature and initial stress under three theories

Othman M. I. A., Abo-Dahab S. M., Alsebaey O. N. S.

Mechanics and Mechanical Engineering

2017

Vol. 21, nr 2

217--232

The model of the equations of generalized magneto-thermoelasticity in an isotropic elastic medium with two-temperature under the effect initial stress is established. The entire elastic medium is rotated with a uniform angular velocity. The formulation is applied under three theories of generalized thermoelasticity: Lord-Shulman, Green-Lindsay, as well as the coupled theory. The Harmonic function is used to obtain the exact expressions for the considered variables. Some particular cases are also discussed in the context of the problem. We introduce the equations of the velocity of p-wave, T-wave and SV-wave. The boundary conditions for mechanical and Maxwell’s stresses and thermal insulated or isothermal are applied to determine the reflection coefficients for p-wave, T-wave and SV-wave. Some new aspects are obtained of the reflection coefficients and displayed graphically and the new conclusions are presented. Comparisons are also made with the results predicted by different theories (CT, L-S, G-L) in the presence of rotation, initial stress, magnetic field, as well as, the two-temperature parameter on the reflection of generalized thermos-elastic waves.