Abstract: A seismic energy source includes a base plate and a block fixedly coupled in a frame. The base plate is configured for contact with a part of the Earth's subsurface to be seismically energized. The frame has a first electromagnet associated therewith. A second electromagnet is disposed in a travelling reaction mass, which is movably disposed in the frame between the first electromagnet assembly and the top block. The reaction mass includes at least a third electromagnet associated therewith.

Abstract: A seismic energy source includes a base plate and a block fixedly coupled in a frame. The base plate is configured for contact with a part of the Earth's subsurface to be seismically energized. The frame has a first electromagnet associated therewith. A second electromagnet is disposed in a travelling reaction mass, which is movably disposed in the frame between the first electromagnet assembly and the top block. The reaction mass includes at least a third electromagnet associated therewith. The source has circuits for selectively energizing the first, second and at least a third electromagnets, and which are configured to energize the first and second electromagnets to repel each other such that the traveling reaction mass is lifted from the first electromagnet, and configured to energize the at least a third electromagnet after a selected delay time to cause attraction between the traveling reaction mass and the top block.

Abstract: A seismic energy source includes a base plate having a first electromagnet thereon. A reaction mass has a second electromagnet thereon. A switchable current source is connected to the first and second electromagnets such that the first electromagnet repels the second electromagnet. At least one damper is functionally connected between the reaction mass and the base plate. The damper is configured to enable faster movement of the reaction mass away from the base plate than toward the base plate.

Abstract: A seismic energy source includes a base plate and a block fixedly coupled in a frame. The base plate is configured for contact with a part of the Earth's subsurface to be seismically energized. The frame has a first electromagnet associated therewith. A second electromagnet is disposed in a travelling reaction mass, which is movably disposed in the frame between the first electromagnet assembly and the top block. The reaction mass includes at least a third electromagnet associated therewith.