Abstract: A gyroscopic vibrator provides a new vibrational energy source for applications such as reflection seismology and shake tables. A gyroscopic mass is rotated at a high angular velocity about a shaft. A control force imparts an oscillatory angular displacement to the shaft, preferrably in a plane perpendicular to the vector direction of the desired vibratory source. The resultant gyroscopic reactionary moment in the shaft includes a force component in the direction of the desired vibratory force. One end of the shaft is constrained by a reaction mass while the other end of the shaft is mechanically coupled to the mass which is to be excited. The resultant excitational forces are substantially greater than the controlled force required to impart the angular displacement to the shaft.