Observations of high-frequency scattered energy associated with the core phase PKKP

Abstract

Stacks of global seismic network data reveal emergent high-frequency (∼1 Hz) energy extending back from the PKKP c caustic at 72° to a distance of about 60°. The arrival's emergent onset, long duration (∼150 s), apparent slowness, and proximity to the core phase PKKP indicate a deep scattering origin. However, the amplitude and timing of the observations are difficult to explain with simple models of PKKP scattering.