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A system composed of a seismic profiler and a towed hydrophone streamer can be successfully used foracoustic velocity measurements of upper sea-bed sediment layers.It is indicated that the T~2-X~2 approachwith Common-Depth-Point processing is the basic way to measure acoustic velocities of arbitrarily dippedlayers.Based on Shah’s ray-tracing formulation,equations for velocity computations of the layers below sea-bottom are derived and procedures to solve them explained.Through the analysis of errors in measuringvelocities,which are caused by deviation of the time-distance curve from an ideal hyperbola,instability oftowing speed,echo-time jitters and streamer declination,the problem of determining the major parameters ofthe measurement system is clarified.
A system composed of a seismic profiler and a towed hydrophone streamer can be successfully used foracoustic velocity measurements of upper sea-bed sediment layers. It is indicated that the T ~ 2-X ~ 2 approach with Common-Depth-Point processing is the basic way to measure acoustic velocities of arbitrarily dipped players. Based on Shah’s ray-tracing formulation, equations for velocity computations of the layers below sea-bottom are derived and procedures to solve them explained. Through the analysis of errors in measuringvelocities, which are caused by deviation of the time-distance curve from an ideal hyperbola, instability of tinging speed, echo-time jitters and streamer declination, the problem of determining the major parameters of the measurement system is clarified.