Figure 4

2-D images obtained from the CCP stacking of radial PRFs along five NE-SW profiles, whose locations are shown in Fig. 1. PRF imaging along the profile (a) AB, (b) CD, (c) EF, (d) GH and (e) IJ. Black doted lines mark the positive peaks associated with 410-km and 660-km Mantle discontinuities, respectively. Thick blue dotted lines mark the low velocity layer atop 410-km (LVL-410) and 660-km (LVL-660) boundaries. Filled green lines mark the 410-km and 660-km depths. This figure is generated using the Funclab software version 1.8.259 (https://doi.org/10.1785/gssrl.83.3.596) and MATLAB software version 9.4.0.813654 (R2018a).