Circular grids of 75 km radius spaced at |$\sim$|55 km (0.5|$^\circ$|⁠) intervals, within which RFs are stacked. Sizes of the circles are proportional to the number of RFs in that grid. The circles are colour coded according to the (a) amplitude ratio of Ps conversion from the LVL-410 and 410 km discontinuities and (b) depth difference between the LVL-410 and the 410 km discontinuity. Open circles represent grids where the LVL could not be found and circles filled with white colour represent grids where LVLs could not be picked due to possible contamination from other phases like crustal multiples.