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 explodes on any solid deformable medium for the purpose of compaction, formation of depressions or destruction, intuitively care is taken to ensure significant amounts 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. Tangential stresses during the free explosion of a charge on a surface are considered significantly less than normal, 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, with symmetry, they 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.