Complex scattering at the core-mantle boundary observed in short-period diffracted P-waves

Abstract

We identified diffracted P-waves, Pdiff, in 15 short-period records from Global Digital Seismic Network data, to infer inheterogeneities near the core-mantle boundary (CMB). These records are classified into three types by their waveforms. From particle motions in the tail and comparison between Pdiff and direct P-waves propagating through the lower mantle, the characteristics of each type are caused by scattering due to heterogeneities deep in the Earth, probably near the CMB. Assuming that the corresponding heterogeneities are only the result of irregular core-mantle topography, we estimate the CMB configuration from the above observations and some simple numerical simulations including the multiple-scattering effect.