Rapid geoacoustic characterization using a surface ship of opportunity

The problem of rapid classification of the sea-floor sediment is addressed using horizontal line array (HLA) acoustic data from a passing surface ship. The data are beamformed to improve signal-to-noise ratio. The rapid geoacoustic characterization (RGC) algorithm involves extracting acoustic observables from the data (normalized striation slope, time spread, and transmission-loss slope). A simple single homogenous sediment layer over an acoustic half-space model is used to compute forward estimates of the acoustic observables. An exhaustive search over the two-parameter model is performed. The two parameters searched over are the sediment compressional speed (Cp), which is a polynomial function of the mean grain size (/spl phi/), and sediment thickness (H). This approach provides a real-time technique for classifying the sediment in a way that successfully reproduces the basic physics of propagation.

[1]  David P Knobles,et al.  Geoacoustic inversion with ships as sources. , 2005, The Journal of the Acoustical Society of America.

[2]  E. Hamilton.  Geoacoustic modeling of the sea floor , 1980 .

[3]  N. Chapman,et al.  Tomographic inversion of geoacoustic properties in a range-dependent shallow-water environment. , 1998, The Journal of the Acoustical Society of America.

[4]  K. Williams,et al.  An effective density fluid model for acoustic propagation in sediments derived from Biot theory. , 2001, The Journal of the Acoustical Society of America.

[5]  Holland,et al.  High-resolution geoacoustic inversion in shallow water: a joint time- and frequency-domain technique , 2000, The Journal of the Acoustical Society of America.

[6]  A. Caiti,et al.  Geoacoustic seafloor exploration with a towed array in a shallow water area of the Strait of Sicily , 1996, OCEANS 96 MTS/IEEE Conference Proceedings. The Coastal Ocean - Prospects for the 21st Century.

[7]  Henrik Schmidt,et al.  Nonlinear inversion for ocean‐bottom properties , 1992 .

[8]  A. Cheng,et al.  From geology to geoacoustics—Evaluation of Biot–Stoll sound speed and attenuation for shallow water acoustics , 1998 .

[9]  M. Buckingham,et al.  Estimating the compressional and shear wave speeds of a shallow water seabed from the vertical coherence of ambient noise in the water column , 1998 .

[10]  Martin Musil,et al.  Range-dependent matched-field inversion of SWellEX-96 data using the downhill simplex algorithm , 1999 .

[11]  Peter Gerstoft,et al.  Parameter estimation using multifrequency range‐dependent acoustic data in shallow water , 1996 .

[12]  O. Godin,et al.  Dispersion of interface waves in sediments with power-law shear speed profiles. II. Experimental observations and seismo-acoustic inversions. , 2001, The Journal of the Acoustical Society of America.

[13]  Peter Gerstoft,et al.  Inversion of broad-band multitone acoustic data from the YELLOW SHARK summer experiments , 1996 .

[14]  Stan E. Dosso,et al.  Estimation of ocean-bottom properties by matched-field inversion of acoustic field data , 1993 .

[15]  Altan Turgut,et al.  Inversion of bottom/subbottom statistical parameters from acoustic backscatter data , 1997 .

[16]  M. Buckingham.  Theory of acoustic attenuation, dispersion, and pulse propagation in unconsolidated granular materials including marine sediments , 1997 .

[17]  M. D. Richardson,et al.  ON THE USE OF ACOUSTIC IMPEDANCE VALUES TO DETERMINE SEDIMENT PROPERTIES , 1993 .

[18]  Fallat,et al.  Hybrid geoacoustic inversion of broadband Mediterranean Sea data , 2000, The Journal of the Acoustical Society of America.

[19]  N. R. Chapman,et al.  Matched field inversion for geoacoustic model parameters using adaptive simulated annealing , 1993 .

[20]  L. A. Thompson,et al.  Broadband sound propagation in shallow water and geoacoustic inversion. , 2000, The Journal of the Acoustical Society of America.

[21]  F. A. Bowles,et al.  Observations on attenuation and shear-wave velocity in fine-grained, marine sediments , 1997 .

[22]  K. Heaney.  Rapid geoacoustic characterization: applied to range-dependent environments , 2004, IEEE Journal of Oceanic Engineering.

[23]  N. R. Chapman,et al.  Matched-field inversion for geoacoustic model parameters in shallow water , 1996 .

[24]  Peter Gerstoft,et al.  Inversion of seismoacoustic data using genetic algorithms and a posteriori probability distributions , 1994 .

[25]  Stephen K. Mitchell,et al.  New measurements of compressional wave attenuation in deep ocean sediments , 1980 .

[26]  Jean-Pierre Hermand,et al.  Broad-band geoacoustic inversion in shallow water from waveguide impulse response measurements on a single hydrophone: theory and experimental results , 1999 .

[27]  W. Kuperman,et al.  Application of waveguide invariants to analysis of spectrograms from shallow water environments that vary in range and azimuth , 1999 .