Identification of crustal and upper mantle heterogeneity by modelling of controlled-source seismic data

Scattered arrivals, which trail the reflection from the '410' discontinuity and a reflection from a shallower depth of ∼320 km, constrain heterogeneity around the top of the transition zone. This heterogeneity is modelled by fluctuations in the 320-460 km depth interval with correlation lengths on the order of 20-40 km by 5-10 km. Scattering from the two shallower heterogeneous zones improves the description of the phases from around the transition zone.