Abstract: A mobile generator for producing waves for seismic exploration. A hammer, mounted on an elongated boom, is dropped to strike an anvil embedded in the ground to create a ground wave. The boom is pivotal between positions selected according to the nature of the wave to be created. A pair of hydraulic piston actuators move the boom between its selected positions. A tensioning device is connected to the cable which drops the hammer in such a manner as to prevent the hammer from rebounding after an impact.

Abstract: A mobile generator for producing seismic waves in the ground, which includes a mobile four-sided frame, a boom having its lower end pivotally connected to the frame, and a worm gear mounted on the frame such that by rotating the worm gear about its longitudinal axis, the boom is pivoted toward a selected impact position. A hammer, mounted on the boom, is raised and then dropped toward an anvil carried beneath the frame on the ground. The anvil has several impact-receiving surfaces such that either a P wave or a shear wave can be generated by pivoting the boom and without relocating the anvil.The anvil structure is positioned on the ground by applying a major portion of the weight of the apparatus on the anvil plate.

Abstract: A mobile generator for producing waves for seismic exploration. An elongated boom guides a wave-generating hammer along a linear path of motion to strike an anvil embedded in the ground, the boom being movable between several adjusted positions including a vertical position for generating a P wave, an inclined position for generating a shear wave, and a horizontal position for transport. An improved anvil for generating either a P wave or a shear wave is also disclosed.