The scattering potential of partial derivative wavefields in 3D elastic orthorhombic media

The scattering potential of partial derivative wavefields in 3D elastic orthorhombic media

Ju-Won Oh and Tariq Alkhalifah, "The scattering potential of partial derivative wavefields in 3D elastic orthorhombic media: An inversion prospective", Geophys J Int 206 (2016): 1740-1760. DOI: 10.1093/gji/ggw238.​
BibTex​ 
Ju-Won Oh, Tariq Alkhalifah
Image processing, Inverse theory, Numerical approximations and analysis, Controlled source seismology, Seismic anisotropy, Wave scattering and diffraction
2016
​Multi-parameter full waveform inversion (FWI) applied to an elastic orthorhombic model description of the subsurface requires in theory a nine-parameter representation of each pixel of the model. Even with optimal acquisition on the Earth surface that includes large offsets, full azimuth, and multi component sensors, the potential for tradeoff between the elastic orthorhombic parameters are large. The first step to understanding such trade-off is analysing the scattering potential of each parameter, and specifically, its scattering radiation patterns. We investigate such radiation patterns for diffraction and for scattering from a horizontal reflector considering a background isotropic model. The radiation patterns show considerable potential for trade-off between the parameters and the potentially limited resolution in their recovery. The radiation patterns of C11, C22 and C33 are well separated so that we expect to recover these parameters with limited trade-offs. However, the resolution of their recovery represented by recovered range of model wavenumbers varies between these parameters. We can only invert for the short wavelength components (reflection) of C33 while we can mainly invert for the long wavelength components (transmission) of the elastic coefficients C11 and C22 if we have large enough offsets. The elastic coefficients C13, C23 and C12 suffer from strong trade-offs with C55, C44 and C66, respectively. The trade-offs between C13 and C55, as well as C23 and C44, can be partially mitigated if we acquire P-SV and SV-SV waves. However, to reduce the trade-offs between C12 and C66, we require credible SH-SH waves. The analytical radiation patterns of the elastic constants are supported by numerical gradients of these parameters.
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