f New vibrator control concept offers industrial use of pseudo-random sweeps in populated areas

For land seismic exploration, the vibratory source dominante increases not only compared to other surface sources but also to explosive sources. Today, the majority of vibroseis surveys are recorded with linear or non-linear sweeps (e.g. logarithmic) that are considered as harmonic sweeps. In urban or industrial areas, the risk of structure resonances makes it mandatory to decrease the vibrator drive level, to truncate the low frequency part of the spectrum, and often to skip the vibrated point. Due to the limitations of conventional vibrator control systems, which are phase-locked to the estimated ground force, very few tests have been successfully conducted to find an alternative to harmonic sweeps suitable for populated areas .