The complete far–field asymptotic description of a point source acting on a transversely isotropic half–space

Author(s):  
Dmitri Gridin ◽  
Larissa Ju. Fradkin
2018 ◽  
Vol 29 (11) ◽  
pp. 2508-2521 ◽  
Author(s):  
Parvez Alam ◽  
Santimoy Kundu ◽  
Shishir Gupta

Propagation of Love-type waves emanating due to a disturbance point source in a transversely isotropic layer of finite thickness laid over a semi-infinite half-space is investigated. The layer is assumed under the influence of magnetic field and hydrostatic state of stress, while the half-space is inhomogeneous. The source point is situated at the common interface of the layer and half-space. Maxwell’s equation and generalized Ohm’s law have been taken into account to calculate the Laurent force induced in the layer. Green’s function technique and Fourier transform are used as a powerful tool to calculate the interior deformations of the model; consequently, we obtain a closed-form dispersion relation for the wave. Six numerical examples for the transversely isotropic layer, namely, beryl, magnesium, cadmium, zinc, cobalt, and simply isotropic, have been considered. The role of magneto-elastic coupling parameter, hydrostatic stress, inhomogeneity, the order of the depth variation in inhomogeneity function, and different examples of the layer on the propagation of Love-type wave has been observed by numerical examples and graphical demonstrations.


2020 ◽  
Vol 110 (2) ◽  
pp. 783-792
Author(s):  
Jie Zhou ◽  
Haiming Zhang

ABSTRACT A Rayleigh wave, often the most visible component in the far-field seismograms, is an important type of seismic-wave motion associated with the Earth’s surface. In this study, we explore some of the general properties of the Rayleigh wave in a homogeneous elastic half-space. Starting from the displacement expressed in the form of a wavenumber integral in the frequency domain, we extract the contribution from the pole in the complex wavenumber plane to obtain the excitation formulae of the Rayleigh wave by the residue theorem for complex integrals. Numerical results are compared with the full wavefield solutions to validate our solutions. By examining the analytical expressions obtained, we explore some basic properties of Rayleigh waves such as the particle motion and geometrical spreading. We also demonstrate that these properties of the Rayleigh wave excited by a point source are slightly different from but mostly consistent with the well-known classical properties of plane Rayleigh waves.


2014 ◽  
Vol 61-62 ◽  
pp. 135-139 ◽  
Author(s):  
Morteza Eskandari-Ghadi ◽  
Seyed Masoud Nabizadeh ◽  
Azizollah Ardeshir-Behrestaghi

Sign in / Sign up

Export Citation Format

Share Document