Back in the early 1940s, M.A. Sadovsky established the fact of correlation of the degree of damage to buildings and structures during explosions with the value of the maximum velocity of ground oscillations on the day surface (at the base of structures). The value of this velocity in the case of instant explosions of concentrated (and equivalent to them spatially dispersed and short-delayed) charges is modeled by a two-parameter argument - the equivalent reduced distance, which displays the energy principle of similarity of phenomena in explosions.