A CONTRIBUTION TO THE INVESTIGATION OF AMPLITUDE CHARACTERISTICS OF VIBRATOR SIGNALS*

The characteristic and information content of a seismic signal depends considerably on the bandwidth of the signal. The Vibroseis system gives the possibility of selecting a certain frequency range. This selection is mostly done in the field by visual comparison, mainly taking into account the characteristic of the signal and the signal/noise ratio. A signal with a good characteristic has, in some cases, an arbitrary amplitude and phase characteristic which is not by itself optimum for the transmission of the desired stratigraphic information. The different factors which influence the amplitude characteristic of a Vibroseis signal are discussed. The present situation is illustrated by some results of measurements of vibrators in different areas. An outlook of how the characteristic of vibrators may be improved is given.