Data Preparation Methods to Utilize Distorted Vibratory Signals in Seismic Tomography

The first arrivals, recorded during a seismic reflection measurement, are suitable for being processed by different tomographical methods as well. The data can be utilized in velocity and absorption estimation of the covered space. The seismic acquisitions targeting the near surface are inherently using single sensors and sources for the measurements. In case of vibratory sources, there is a possibility to increase the accuracy of the tomographical parameter determination by utilizing the full energy emitted by the source. For vibratory sources there are methods to form a new ground force signal estimate by data combination, which can describe properly even its distorted nature. As a result the total transmitted energy can be taken into account in the calculations – the fundamental part and the higher harmonics as well. These harmonic components can be fed into the inversion, as they were measured independently, to increase the stability and accuracy of the tomography process. Also the source signal estimation, together with special analysis techniques, can qualify the first arrival data at each offset and frequency. These quality grades could be submitted into the tomography algorithm as weighting factors to filter out erroneous data for reliability improvement.