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Improving the processing of vibroseis data for very shallow high‐resolution measurements
- Source: Near Surface Geophysics, Volume 5, Issue 3, Dec 2007, p. 173 - 182
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- 01 Feb 2005
- 18 Dec 2018
Abstract
Very shallow seismic surveys, i.e. 20–100 m target depth, require a large bandwidth of high frequencies to ensure detailed resolution. A survey with a small hydraulic vibrator across young glacial structures in northern Germany that gave unsatisfactory results was repeated with monitored vibrator motions. This enabled us to use the groundforce signal as correlation operator and to apply sweep deconvolution.
The application of the groundforce signal resulted in a distinct improvement compared to correlation using the reference sweep, whatever the data compression technique used. This is due to harmonics that show high amplitudes at high frequencies and contribute considerably to signal energy. Sweep deconvolution works at least as well as correlation. Due to the minimum‐phase nature of sweep deconvolved data, this technique, if combined with a minimum‐phase deconvolution, gave the best results. The geological target, consisting of thin interstadials embedded in a sequence of sands deposited during the last glaciation, could be imaged much more clearly than before.