Azimuthally averaged radial surface density profiles at specific times (reported on top of the panels). At the time of top and middle panels, the migration behaviour has clearly bifurcated with slow outward migration for discs NW and S01 and rapidinward migration for the simulation sets with thicker active layers as well as for the case H_in. Rapid outward migration is observed for the case H_out. Despite the differences in the migration regimes, the gap depth slowly evolves from the time corresponding to the middle panel to theone represented in the bottom panel: gaps are deeper in all the simulations sets in which the planet blocks the flow from the active layers.