| 摘要 |
Electromechanical device for generating elastic waves in a material medium such as the subsoil in a frequency range where the wavelengths of the waves generated are great in view of the dimensions of the device, and method for implementing it. The device comprises one or more vibrators suited to be buried in the medium, associated with a control system. Each vibrator comprises at least one inertia mass (1), several plates (2, 3) providing mechanical coupling with the medium, electromechanical transducers (4, 5) connecting inertia masses (1) to plates (2, 3). Control system (7) is suited to apply to the various transducers (4, 5) respective control signals so that the resulting elastic wavefield generated in the medium by the device is preferentially oriented in one or more directions. This focused wavefield can be obtained directly by applying suitable control signals to the various transducers of each vibrator or by carrying out several successive emission phases with different wavefields so that, by combining the seismograms obtained during these different phases, the equivalent wavefield is focused, or by combining focused wavefields emitted by several simple vibrators. Application: onshore seismic prospecting for example.
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