This report deals with mathematical problems in seismology. Homogeneous and layered half-spaces are discussed. Expressions are found for the displacement caused by a point source in such models. Numerical results are presented for the displacement caused by the sudden injection of a volume into a homogeneous half-space after the model of E. Pinney. Pinney's results are extended. Numerical ray-tracing calculations are presented. Most of the original work in the report is chiefly concerned with the development of an iteration-variation method for solving wave equations in media of variable index of refraction. This method is promising and is being actively investigated.