Time domain scattering of elastic waves by a cavity, represented by radiation from equivalent body forces

2017 ◽  
Vol 115 ◽  
pp. 43-50 ◽  
Author(s):  
Chao Yang ◽  
Jan D. Achenbach
2019 ◽  
Vol 49 (12) ◽  
pp. 1723
Author(s):  
Wang Jue ◽  
Li Peijun ◽  
Bao Gang ◽  
Hu Bin

Geophysics ◽  
1976 ◽  
Vol 41 (3) ◽  
pp. 441-458 ◽  
Author(s):  
Paul G. Richards ◽  
Clint W. Frasier

We have studied scattered pulse shapes by modeling inhomogeneities as a sequence of infinitesimally thin homogeneous layers. With oblique incidence of plane P or SV waves, the reflected‐converted‐transmitted waves are obtained by taking the calculus limit for the sum of primary interactions of the incident wave with all layer boundaries. The resulting scattered waves thus present themselves naturally in the time domain. For an incident impulse, the scattered pulse shape is merely an analytic function of the depth from which scatter has taken place within the inhomogeneity. The direct application of this simple method appears to be new, and we have found it remarkably accurate when compared with methods in which higher‐order boundary interactions are also retained (i.e., Haskell methods and an adaptation in the time domain which also keeps all multiples). In specific studies of P-waves incident (up to 30 degrees away from the vertical) upon a 5 km thick crust‐mantle transition, between materials having impedance ratio 1:2.8, we find the scattered pulse shapes are given adequately by our theory, for the passband of short‐period seismometers. Indeed, the theory remains remarkably accurate even for long periods, being in error by only 8 per cent at zero frequency.


Author(s):  
Michael H. Meylan ◽  
Ross C. McPhedran

We study the scattering of elastic waves by platonic clusters in the time domain, both for plane wave excitations and for a specified initial wave profile. We show that we can use an analytical extension of our problem to calculate scattering frequencies of the solution. These allow us to calculate approximate solutions that give the flexural wave profile accurately in and around the cluster for large times. We also discuss the early-time behaviour of flexural waves in terms of the classical models of Sommerfeld and Brillouin.


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