Synthetic seismogram generation from sediment composition data - An initial study in the southwest Brazil Basin

A synthetic seismogram was constructed for Deep-Sea Drilling Site 515 in the Brazil Basin by convolving a measured 3.5 kHz seismic pulse with a reflectivity profile constructed from geologic parameters. Acoustic impedance was computed from detailed high-resolution carbonate measurements at 10 cm intervals over 62 m of Hydraulic Piston Core section (Hole 515A). The synthetic seismogram and two surface-ship 3.5 kHz profiles which cross near the site show a striking similarity to each other, suggesting that carbonate content is controlling the 3.5 kHz record at this site. Although the interference between pulses reflected from adjacent carbonate peaks occasionally changes the character of the reflected profile, specific reflecting horizons can be correlated with particular carbonate peaks. Previous studies suggest that the carbonate peaks in this core correspond to turbidites. The technique can be used to generate synthetic seismograms for sediment cores where the primary physical property information does not exist.