To study the mechanism of the source of acoustic emission, we analyze the transient waves which ate generated by four kinds of point sources, a single force, double force, and center of dilatation, all inside an infinite plate, and a single force on the surface of the plate. Some of these forces or a combination of them could be used to model the dynamic process of material defects. The analysis is based on the generalized ray theory and Cagniard’s method. Transient solutions are obtained by evaluating the ray integrals with a complex algorithm. Numerical results are shown for receivers that are located at a distance up to six plate thickness, and for a duration less than ten transit time for a P-wave to cross the thickness of a plate. © 1979, Walter de Gruyter. All rights reserved.