SH waves from torsional sources in semi-infinite heterogeneous media

1971 ◽  
Vol 87 (1) ◽  
pp. 55-65 ◽  
Author(s):  
R. S. Sidhu
Keyword(s):  
Heterogeneous Media ◽  
Sh Waves

Disturbances in semi-infinite heterogeneous media generated by torsional sources. I

1972 ◽  
Vol 62 (2) ◽  
pp. 541-550
Author(s):  
R. S. Sidhu
Keyword(s):  
Heterogeneous Media ◽  
Formal Solution ◽  
Homogeneous Medium ◽  
Finite Depth ◽  
Free Boundaries ◽  
Axially Symmetric ◽  
Sh Waves ◽  
Reflected Waves ◽  
Buried Point ◽  
Heterogeneous Layer

abstract This paper studies the generation of axially symmetric transient SH waves in semi-infinite heterogeneous media in which μ and ρ vary with depth. The sources generating these waves are taken in the form of time-dependent torsional-body forces of finite dimensions. The solution is obtained using Hankel and Laplace transforms and Green's function. The disturbance from a buried point source of impulsive type is discussed in two cases, (a) μ = μo(1 + ɛz)2, ρ = ρo (1 + ɛz)2, (b) μ = μoe2az, ρ = ρoe2az. It is shown that, in contrast to the results for a homogeneous medium, in case (i), the wave reflected by the free surface generates secondary disturbances which trail behind the wave front and die out as t increases; the incident wave in this medium generates no such disturbance. In case (ii), however, both the incident as well as the reflected waves generate secondary disturbances. Formal solution for the disturbance in a heterogeneous layer of finite depth with stress-free boundaries is discussed in Appendix II.

Elastic constants of transversely isotropic media from constrained aperture traveltimes

Geophysics ◽  
1994 ◽  
Vol 59 (4) ◽  
pp. 658-667 ◽  
Author(s):  
Reinaldo J. Michelena
Keyword(s):  
Elastic Constants ◽  
Heterogeneous Media ◽  
Transversely Isotropic ◽  
System Of Equations ◽  
Sh Waves ◽  
Velocity Models ◽  
Transversely Isotropic Media ◽  
Isotropic Media ◽  
P And Sv Waves ◽  
Homogeneous Media

The elastic constants that control P‐ and SV‐wave propagation in a transversely isotropic media can be estimated by using P‐ and SV‐wave traveltimes from either crosswell or VSP geometries. The procedure consists of two steps. First, elliptical velocity models are used to fit the traveltimes near one axis. The result is four elliptical parameters that represent direct and normal moveout velocities near the chosen axis for P‐ and SV‐waves. Second, the elliptical parameters are used to solve a system of four equations and four unknown elastic constants. The system of equations is solved analytically, yielding simple expressions for the elastic constants as a function of direct‐ and normal‐moveout velocities. For SH‐waves, the estimation of the corresponding elastic constants is easier because the phase velocity is already elliptical. The procedure, introduced for homogeneous media, is generalized to heterogeneous media by using tomographic techniques.

Vibroacoustic dynamics of heterogeneous media and NPP structures

2014 ◽  
Vol 2014 (1) ◽  
pp. 99-110
Author(s):  
Vladimir Sergeevich Fedotovskij ◽  
Tat’yana Nikolaevna Vereschagina ◽  
Svetlana Valer’evna Lunina ◽  
Evgeniya Aleksandrovna Ivanova
Keyword(s):  
Heterogeneous Media

Integral Transformation of Multidimensional Heat Conduction Problems in Heterogeneous Media

2017 ◽  
Author(s):  
Carolina Palma Naveira Cotta ◽  
Renato Machado Cotta ◽  
Anderson Pereira de Almeida
Keyword(s):  
Heat Conduction ◽  
Heterogeneous Media ◽  
Integral Transformation
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