Large‐offset seismic surveying using ocean‐bottom seismographs and air guns: Instrumentation and field technique

Repeatable, closely spaced signal sources from large‐capacity air guns and detection and recording of signals using highly flexible, microprocessor‐controlled, digital ocean‐bottom seismographs allow us to acquire high‐quality, large‐offset, marine seismic refraction and reflection data. The acquired data are readily adaptable to various processing techniques originally developed for seismic reflection data. There are several requirements and problems specific to the technique. For example, bubbly signals from one or two large‐capacity air guns are often preferable to bubble‐suppressed signals from tuned arrays in identifying weak arrivals at large offset distances. Recorded water‐wave signals at near ranges provide precise locations of detectors relative to shots.