02167nas a2200301   4500000000100000000000100001008004100002260000800043653001400051653001500065653002600080653001200106653001600118653000900134653001600143100001200159700001200171700001300183700001200196700001800208700001300226245011900239856006100358300001400419490000800433520141000441020001401851       2006                            d  cNov10aACOUSTICS10aDISPERSION10aGAS-BEARING SEDIMENTS10aIN-SITU10aPROPAGATION10asand10aSOUND SPEED1 aG. Robb1 aAI Best1 aJ.K. Dix1 aJ. Bull1 aT.G. Leighton1 aP. White00aThe frequency dependence of compressional wave velocity and attenuation coefficient of intertidal marine sediments  uhttp://asadl.org/jasa/resource/1/jasman/v120/i5/p2526_s1  a2526-25370 v1203 aTo advance the present understanding of the frequency dependence of compressional wave velocity and attenuation in marine sediments a series of well-constrained in situ acoustic transmission experiments (16 to 100 kHz) were performed on intertidal sediments. The processing techniques incorporated in situ spreading losses, sediment to transducer coupling and thorough error analyses. Significant variations in velocity and attenuation were observed over scales of tens of meters within the same sediment type. Velocity was generally nondispersive in sands, while highly variable silt velocities prevented any meaningful dispersion estimates from being determined. The attenuation coefficient was proportional to frequency for 75\% of the experimental sites. The measured compressional wave properties were compared to predictions from the Grain-Shearing model. For the sandy sites, the phase velocities predicted by the Grain Shearing model exceed those measured, while predicted phase velocities agreed with measured group velocities at specific locations for the silty sites. For both silts and sands predicted dispersions are comparable to the intrinsic errors in group velocity and hence undetectable. The attenuation coefficients predicted by the Grain Shearing model adequately describe the measured attenuation coefficients, within the observed variability. (c) 2006 Acoustical Society of America.  a0001-4966