A numerical treatment of body forces which are equivalent to seismic sources in elastic media is given. This treatment allows the formulation of sources of different orders and with different spatial and temporal dependence. It includes internal sources having different extensions in different directions in space; the internal sources can be located arbitrarily close to a free surface or an interface. The method also handles distributed surface forces acting on a finite area.
Complete solutions, calculated for impulsive sources of first, second, and third order, buried in an elastic half-space and extending over a finite region, and for a distributed surface loading, are illustrated.