Hurrah for Hussar! Comparisons of stacked data

J. Helen Isaac and Gary F. Margrave


We processed, stacked and post-stack migrated twelve data sets having combinations of four sources and three receivers. The same basic processing was applied to all data but no filters were applied. The dominant frequency of the unfiltered stacks is around 10 Hz with a steep drop off to 30-40 Hz, after which the spectra remain fairly flat until near 70 Hz for the vibroseis data, where the power increases to rise a little towards 100 Hz. The dynamite data show the greatest variation in power over the signal band and the least power at high frequencies.

Filtering the data to retain only frequencies of 1-10 Hz show the low-end spectra of data recorded by the 10 Hz and 4.5 Hz geophones to be similar for each corresponding source, while the Vectorseis spectra are different. In every case there is an increase in power towards 10 Hz, except for the Vectorseis dynamite data. This increase is steep up to 4 Hz and fairly linear from 4 Hz to 10 Hz for the 10 Hz and 4.5 Hz geophones. The spectra are much flatter for the Vectorseis data and that of Vectorseis dynamite data are different from all the others, having a peak at 6 Hz.

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