This chapter starts with the glossary of terms used to describe seismic sources, and a short description of seismic potency, radiated seismic energy, and associated parameters like apparent stress, energy index, and apparent volume. There is a short description of the static solution for a circular crack subjected to a uniform shear strain given by Eshelby that explains the basic source scaling relations, and a section on the circular \(\omega ^{2}\) source model by Brune. While Brune’s model fits the spectra of seismic events recorded in deep high stress mines, it does not work as well in many mines with a weaker inhomogeneous rock mass and/or at intermediate depth and in caving mines. Seismic events in such an environment radiate less energy per unit of deformation at source. Therefore Chap. 2 introduces more general point source models suggested by Beresnev and Atkinson that allow for “softer spectra”, e.g. \(\omega ^{2.5}\) or \(\omega ^{3}\) . It also describes the final static deformation and strains induced by the double-couple source, gives the radiation pattern for the near, intermediate, and far fields and derives the expression for the surface of such a source for a given inelastic strain drop.