A variable pressure wave propagation velocity is developed and analyzed in ground materials which may be characterized by an exponential density-pressure relationship. The peak overpressure dependence is minor in the low pressure range and the propagation velocity of the pressure waves is essentially a constant, in fact, it is the seismic P-wave propagation velocity. Pressure dependence becomes increasingly more significant at peak overpressures exceeding 1 kbar (108 Pa). At very high pressure levels encountered only in shockwaves at and above 10 kbar (109 Pa), the initial mechanical characteristics of the ground materials becomes less significant, and the propagation velocity depends primarily upon the peak overpressure. ¿ American Geophysical Union 1992