In an approximate theoretical analysis of longitudinal and transverse elastic waves generated in a solid mass under uniformly distributed action at the boundary of a cylindrical cavity of finite length, the real cavity is replaced by a cavity of infinitesimal radius.

When a charge is exploded on a solid deformable medium with the aim of compaction, the formation of depressions or destruction, care is intuitively taken to ensure significant values of vertical displacements or particle displacement velocities in the corresponding areas of the surface. Maximum displacements (or velocities) are expected in those areas of the boundary surface where the greatest compressive normal stresses are created. Shear stresses during free explosion of a charge on a surface are considered significantly less than normal ones, and they are often neglected. Horizontal displacements are also neglected, which naturally decrease away from the point of explosion according to the principle of radiation, and at the point of explosion, under symmetry, should be zero.

Consider the dynamic elastic field in the explosion of an elongated charge parallel to one of the exposed surfaces of a rock massif ledge. Mathematically, such an effect can be described quite accurately by direct and reflected from the exposed surfaces perturbations caused by a source moving with detonation velocity such as a center of expansion.