The structure of the Earth's inner core is not well known between depths of∼ 100–200 km
beneath the inner core boundary. This is a result of the PKP core phase triplication and the
existence of strong precursors to PKP phases, which hinder the measurement of inner core
compressional PKIKP waves at epicentral distances between roughly 143 and 148°.
Consequently, interpretation of the detailed structure of deeper regions also remains difficult.
To overcome these issues we stack seismograms in slowness and time, separating the PKP …