Abstract: A seismic vibrator includes a baseplate having a surface configured to couple to a ground surface. A driver is coupled to the baseplate and is configured to move the baseplate in a vibratory manner. A decoupling system is coupled to a part of the baseplate other than the ground-contacting surface. The decoupling system includes a first layer having a Young's modulus greater than that of a second layer coupled to the first layer. The second layer is coupled to the baseplate. The Young's moduli, thicknesses and masses of the first and second layer are selected to provide the decoupling system with a resonant frequency of at most, a spatial aliasing frequency of seismic sensors deployed on the ground surface or a lowest seismic frequency of interest.

Abstract: In one embodiment of the invention a method includes (a) operating a combustion engine at a first activity level corresponding to a first noise level; (b) charging an accumulator with a first pressure input; (c) lowering engine activity level of the engine to a second activity level corresponding to a second noise level that is lower than the first noise level; and (d) seismic sweeping with the vibrator based on the first pressure input and lowering engine noise from the first noise level to the second noise level.

Abstract: A seismic vibrator includes a baseplate having a surface configured to couple to a ground surface. A driver is coupled to the baseplate and is configured to move the baseplate in a vibratory manner. A decoupling system is coupled to a part of the baseplate other than the ground-contacting surface. The decoupling system includes a first layer having a Young's modulus greater than that of a second layer coupled to the first layer. The second layer is coupled to the baseplate. The Young's moduli, thicknesses and masses of the first and second layer are selected to provide the decoupling system with a resonant frequency of at most, a spatial aliasing frequency of seismic sensors deployed on the ground surface or a lowest seismic frequency of interest.

Abstract: In one embodiment of the invention a method includes (a) operating a combustion engine at a first activity level corresponding to a first noise level; (b) charging an accumulator with a first pressure input; (c) lowering engine activity level of the engine to a second activity level corresponding to a second noise level that is lower than the first noise level; and (d) seismic sweeping with the vibrator based on the first pressure input and lowering engine noise from the first noise level to the second noise level.