Scattering 1
Scattering 1 : Dispersion and irregular spreading of water waves leading to attenuation and energy dissipation of the wave system. In reference to seismic waves, the effects of scattering on measurements of intrinsic attenuation, at frequencies that are so low that wavelengths are much larger than linear dimensions of a heterogeneity, the effects of scattering can usually be neglected for the propagation of body waves. Very low frequencies are in the domain of Rayleigh scattering, in which the energy loss in the forward direction is proportional to the inverse fourth power of frequency. At sufficiendy low frequency, the medium behaves like an equivalent medium, having properties that are an average of small-scale heterogeneities. At higher frequencies, those in which the wavelength is on the order of the scale length of heterogeneities, the presence of the heterogeneities can profoundly alter the propagation of the wave field. For wavelengths much smaller than the scale length of the heterogeneities, it is possible in some situations to calculate the effect of scatterers by using ray theory. The distribution and shape of the scatterers, however, must first be known or assumed
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