The apparent attenuation of a scattering medium

摘要: We report the results of some numerical experiments that bring out lowpass characteristics a purely elastic medium with heterogeneous velocity structure. Although typical fluctuation is spatially confined within less than wavelength, waves propagating over sufficiently long path suffer major cumulative effects. summarize removal high frequencies during transmission by frequency-independent apparent Q, and show attenuation intrinsic friction scattering are approximately additive. propose diagnostics might help to distinguish presence fluctuations resultant from anelasticity true dissipation. When dominates friction: (1) coda transmitted wave contains relatively higher initial pulse; (2) deduced power spectrum greater phase spectrum; (3) compressional shear Q's equal; (4) estimates Q made reflected vary frequency, while do not. also outline several topics in theory propagation will be relevant satisfactory interpretation short-period observations, if amplitude such signals affected scattering.