Strong scattering of short-period seismic waves by the core-mantle boundary and the P-diffracted wave

We interpret the long-tail-in-time (up to 3 minutes) decay of short-period P-diff as being due to multiple scattering within D '', which, for this purpose, is assumed to be an heterogeneous region with a low velocity zone just next to the core-mantle boundary. A simple multiple scattering theory, generalized for a two-dimensional spherical geometry, provides good agreement with observations for values of the scattering and attenuation coefficients (eta) of about 10(-3) km(-1).