Sub-bottom Profiling

Sub Bottom Profiling (SBP) systems are high resolution acoustic measurement systems for imaging shallow sediments, usually consisting of a single channel source mounted on a vessel. Their applications range from the description of shallow sediments in rivers and lakes, the visualization of underwater mass movements to the detection of objects. Similar to a standard seismic reflection survey, these sources send sonic pulses into the shallow sediments of the river or lake bed. Sound pulses are then reflected at sediment layer boundaries where differences exist in the acoustic impedance of the upper and lower layers. The reflected sound pulses are then recorded by the SBP measurement system. This procedure is typically repeated along a 2D line and the individual traces are assembled to produce a 2D seismic section that can then be interpreted in a seismic interpretation software package.

Various measurement systems are available for acquiring SBP data, which differ in source type, resolution, and frequency, and thus penetration depth. Among these, "Sparker" (50 Hz - 4 kHz) systems have the highest penetration depths of up to 1000 m, "Boomer" (500 Hz - 5 kHz) systems reach up to 100 m, and "Pinger" (3.5 kHz - 7 kHz), "Chirper" (3 kHz - 40 kHz), and "Parametric" (100 kHz) systems have penetration depths of less than 100 m.