Diffraction of elastic waves from a 2D thin elastic inclusion: null field approach

2002 ◽  
Author(s):  
Ya.I. Kunets ◽  
V.V. Matus ◽  
V.O. Mishchenko ◽  
V.V. Porochovsky
Keyword(s):  
Elastic Waves ◽  
Elastic Inclusion ◽  
Field Approach ◽  
Null Field ◽  
Thin Elastic Inclusion ◽  
Diffraction Of Elastic Waves

Scattering of plane elastic waves at rough surfaces. II

1963 ◽  
Vol 59 (1) ◽  
pp. 231-248 ◽  
Author(s):  
Iya Abubakar
Keyword(s):  
Incident Wave ◽  
Elastic Waves ◽  
Rayleigh Waves ◽  
Irregular Surfaces ◽  
Elliptic Orbits ◽  
Incident Plane ◽  
Diffraction Of Elastic Waves ◽  
Axis Of Symmetry ◽  
Point Of Intersection ◽  
Second Wave

AbstractThis is a continuation of (1) on the two-dimensional problem of the diffraction of elastic waves by irregular surfaces. The effect of an irregular surface with an isolated irregularity like a trough or ditch on incident plane harmonic P- and SV-waves is discussed. The maximum depth of the ditch is assumed small compared to the wavelength of the incident wave.It is found that, when either a P- or an SV-wave is incident on such a boundary, besides the specularly reflected P- and SV-waves whose amplitudes are independent of the curvature of the surface there exist scattered waves travelling in various directions. In particular the diffracted zone contains the following second wave-types whose amplitudes are proportional to the depth of the ditch: (i) direct reflected P- and SV-waves, which at large distances appear to diverge from the point of intersection of the axis of symmetry of the ditch and the horizontal plane asymptotic to the boundary if the ratio of the wavelength of the incident wave to the half-width of the ditch is large. If the ratio is small these waves are reflected in the specular directions, (ii) A ‘secondary S-wave’ which finishes as P having travelled most of the way as an SV-wave. Its energy is confined to the neighbourhood of the free surface, (iii) A secondary P-wave which travels along the surface and finally emerges into the medium as an SV-wave at the critical angle for the medium, (iv) Rayleigh waves whose particle motion is in elliptic orbits.

Diffraction of elastic waves by the core of the Earth

1961 ◽  
Vol 51 (1) ◽  
pp. 35-49
Author(s):  
Leon Knopoff ◽  
Freeman Gilbert
Keyword(s):  
Half Plane ◽  
Elastic Waves ◽  
Amplitude Distribution ◽  
Laboratory Model ◽  
Shadow Zone ◽  
Adequate Explanation ◽  
Model Experiments ◽  
The Core ◽  
The Earth ◽  
Diffraction Of Elastic Waves

Abstract The problem of the diffraction of a seismic pulse by the core of the Earth is investigated theoretically. The result is compared to that of diffraction by a half-plane. The differences are striking. Laboratory model experiments have been performed to verify the theoretical approximations in their regions of validity, and to complement the theory elsewhere. The curves, thus obtained, of the theoretical amplitude distribution in the shadow of the Earth's core agree very well with the observations of Gutenberg. It is therefore concluded that diffraction is a completely adequate explanation for the amplitude distribution in the shadow zone.

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