An evaluation of peak and bubble tuning in sub-basalt seismology: modelling and results from OBS data

As part of the iSIMM project (White et al. 2002), a 6360 in3 airgun source array was used to acquire, in two passes, a deep seismic profile into a 480 km array of ocean bottom seismometers (OBS) east of the Faroe Islands. The first pass used peak tuning, and the second pass used bubble tuning, with other source parameters constant. The objective was to deliver low frequency energy for deep, long-offset, sub-basalt penetration. The results suggest that towing large guns deep is more important than the tuning method. However, for the gun configuration used, the bubble-tuned data are more compact, less reverberant and easier to pick.