Western were using a source extended both in time and along the borehole for this work. As received, the raw data had been correlated so that the wavelets were somewhat collapsed. Nevertheless, the direct arriving compressional waves had well developed precursive energy, and the normal minimum phase deconvolution was clearly inappropriate.
The compressional waves were quite clean and similar in character, and the first plan called for picking, shifting, and stacking to form the estimate.