Two problems of pressure distributions applied to an elastic half-space over a circular pressure zone whose center is fixed but whose radius changes non-uniformly with time are considered. In one case, the pressure depends only on time; in the other case, the pressure varies with the radial distance from the pressure zone center. Complete transform solutions are obtained and several wave propagation aspects are briefly studied, with emphasis on the Rayleigh pole contributions and the associated propagating singularities. The effects of some specific zone time-histories on the Rayleigh pole disturbances at the half-space surface are considered. Some characteristics of a given time-history appear to be manifested in the corresponding disturbance.