Multipolar moments spectra around clusters (upper red curves) and around random location (lower blue curves) for the two annuli 0.25 ≤ R/R_vir< 0.5 and 1 ≤ R/R_vir< 4 (left and right-hand panels respectively) for the z = 0 simulation output. There is an excess of power around clusters as compared to random localisations, since the density field is denser. At large m (substructures scales), their spectra differ by a nearly constant multiplicative factor , which is the first order signature of the dynamical evolution of the shape of clusters (see Sect. 3.3).