Sub-bottom profiling surveys are generally used to identify and characterize layers of sediments under the sea bed. Hard objects buried under the sea bed such as ships etc. can also be mapped using SBP surveys. Generally SBP and Side Scan Sonar Surveys are deployed along with standard Hydrographic Surveys for meeting the overall objective of Marine Survey
In SBP Surveys pulse is transmitted towards the sea bed like Side Scan Sonar Survey, however, part of this pulse is reflected and part is penetrated under sea bed. The pulses traveling under the sea bed are refracted and reflected while traveling in the sea bed sediments. These reflected and refracted pulses are recorded by the hydrophones and travel time taken by pulses are used to map the type and thickness of sub-bottom layers of sea bed.
Lower - frequency pulses achieve greater penetration but lower-resolution; however, higher-frequency pulses achieve higher resolution but less deep penetration