This paper deals with the evaluation of damage due to boulder impact on rockfall protection embankment thanks to external methods. A 4 m high, 8 m long three layered structure is built using cells filled with different material according to their location in the structure. The structure is impacted by a 6500 kg spherical boulder with a maximal impact energy of 2000 kJ. The behaviour of the structure is first investigated using topographic surveys. Then, the results are compared with geophysical measurements. Results show that a low-energy impact leads to (i) the densification of both front and inner-layers associated with the swelling of the materials of the rear layer in the impact plane, and (ii) to the readjustment of internal materials which induces a local densification in a plane offset of 2 m. A high-energy impact induces large deformations on both inner and rear layers. These results are confirmed by seismic velocities which decrease with successive impacts.