Seabed sediment attenuation profiles from a movable sub-bottom acoustic vertical array Available to Purchase

The acoustic lance [S. S. Fu, M.Sc. Thesis, University of Hawaii at Manoa (1994); Fu et al., J. Acoust Soc. Am. 99, 234–241 (1996)] consists of a linear array of acoustic receivers below an acoustic source, all mounted on the outside of a core barrel or independent probe which is embedded in the seafloor. In earlier studies lance travel time data were processed to give in situ compressional wave sound speed as a function of depth. In this study lance waveforms are processed to extract compressional wave attenuation $A=Q−1$ as a function of depth. The processing technique is unusual because the $L1$ norm is used instead of the usual $L2$ norm, the model space of attenuation profiles is exhaustively searched within the limits of discretization, and the marginal posterior probability density function of attenuation is computed explicitly at each depth. The technique is described in terms of Bayesian inverse theory using the notation of Tarantola.