We performed density functional theory calculations and we calculated Scanning Tunneling Microscopy images (constant height mode) on twisted bilayer graphene (BLG). The STM theoretical images show the graphene structure and also superstructures. The roughness associated to the surface carbon atoms appears over a large oscillation amplitude which is in agreement with the “giant corrugation” experimentally reported by several authors. Additionally we found a strong dependence between the corrugation amplitude of the calculated images and the bias voltage considered. These results suggest that superstructures in twisted BLG have to do mainly with a redistribution of the electronic density and that deformations introduced by tip-sample mechanical interaction could be of second order.