Open AccessAmplitude fluctuations due to diffraction and refraction in anisotropic random media: implications for seismic scattering attenuation estimates
Author(s) -
Müller T. M.,
Shapiro S. A.
Publication year - 2003
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1046/j.1365-246x.2003.02020.x
Subject(s) - attenuation , amplitude , anisotropy , scattering , anelastic attenuation factor , seismic wave , physics , refraction , plane wave , computational physics , geology , optics , geophysics
SUMMARY We calculate the variance of the log‐amplitude within the Rytov approximation for plane waves propagating in weakly inhomogeneous and statistically anisotropic random media. Since there is a simple relation between the log‐amplitude variance and the attenuation coefficient of seismic primaries in the weak wavefield fluctuation regime, we also obtain scattering attenuation estimates that additionally depend on the aspect ratio of longitudinal and transverse correlation scales of the inhomogeneities. These estimates can be useful for the statistical characterization of anisotropic, large‐scale inhomogeneities (large compared with the wavelength of the probing pulse) in the Earth crust and mantle, such as fault zones. With the help of plane‐wave‐transmission numerical experiments using the finite‐difference method we compute the log‐amplitude variance as a function of the propagation distance and observe reasonable agreement with the analytical results. We discuss the implications of our results in the context of seismic scattering attenuation estimations.