Factors affecting the evaluation of scattering attenuation

Tae-Kyung Hong, B.L.N. Kennett and Ru-Shan Wu (2003)

AGU Fall Meeting, San Francisco, Dec. 8-12, 2003

The scattering of waves is a near ubiquitous phenomenon in the earth and has been widely studied in seismology. Scattering attenuation can be calculated by a formulation based on an approximation allowing for both multiple forward-scattering and a single backscattering process. In this approximation possible interaction between scattering in the forward and backward directions is neglected. In this study we examine the effects of multiple scattering and propagation distance on the evaluation of scattering attenuation through numerical experiments on highly heterogeneous models. A change in propagation distance results in the variation of the radius of the Fresnel zone, which controls the interference volume of scattered waves. We find that primary waves display a characteristic attenuation pattern depending on both the frequency content of the incident waves and the change in propagation distance. On the other hand, the coda energy is determined to be nearly constant for changes in the random model and perturbation level.