Observations of the R reflector and sediment interface reflection at the Shallow Water '06 Central Site.

Acoustic bottom-interacting measurements from the Shallow Water '06 experiment experiment (frequency range 1-20 kHz) are presented. These are co-located with coring and stratigraphic studies showing a thin (approximately 20 cm) higher sound speed layer overlaying a thicker (approximately 20 m) lower sound speed layer ending at a high-impedance reflector (R reflector). Reflections from the R reflector and analysis of the bottom reflection coefficient magnitude for the upper two sediment layers confirm both these features. Geoacoustic parameters are estimated, dispersion effects addressed, and forward modeling using the parabolic wave equation undertaken. The reflection coefficient measurements suggest a nonlinear attenuation law for the thin layer of sandy sediments.

[1]  N. Chapman,et al.  Bayesian geoacoustic inversion in a dynamic shallow water environment. , 2008, The Journal of the Acoustical Society of America.

[2]  Mark V. Trevorrow,et al.  Summary of marine sedimentary shear modulus and acoustic speed profile results using a gravity wave inversion technique , 1991 .

[3]  Richard B. Evans,et al.  Shallow-water sound transmission measurements on the New Jersey continental shelf , 1995, IEEE Journal of Oceanic Engineering.

[4]  J. Goff,et al.  Seabed characterization on the New Jersey middle and outer shelf: correlatability and spatial variab , 2004 .

[5]  Jim Austin,et al.  Late Quaternary sedimentation off New Jersey: New results using 3-D seismic profiles and cores , 1992 .

[6]  J. Milliman,et al.  Late Quaternary Sedimentation on the Outer and Middle New Jersey Continental Shelf: Result of Two Local Deglaciations? , 1990, The Journal of Geology.

[7]  J. Goff,et al.  Basal inflection-controlled shelf-edge wedges off New Jersey track sea-level fall , 2005 .

[8]  Kevin L. Williams,et al.  Direct measurement of sediment sound speed in Shallow Water '06. , 2008, The Journal of the Acoustical Society of America.

[9]  Michael G. Parsons,et al.  An assessment of fuzzy logic vessel path control , 1995, IEEE Journal of Oceanic Engineering.

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

[12]  J. D. Holmes,et al.  Nonlinear frequency-dependent attenuation in sandy sediments. , 2007, The Journal of the Acoustical Society of America.

[13]  M. D. Collins.  A split‐step Padé solution for the parabolic equation method , 1993 .

[14]  N. Chapman,et al.  Quantifying the uncertainty of geoacoustic parameter estimates for the New Jersey shelf by inverting air gun data. , 2007, The Journal of the Acoustical Society of America.

[15]  Darrell R. Jackson,et al.  Comparison of sound speed and attenuation measured in a sandy sediment to predictions based on the Biot theory of porous media , 2002 .

[16]  J. Austin,et al.  Shallowly buried, enigmatic seismic stratigraphy on the New Jersey outer shelf: Evidence for latest Pleistocene catastrophic erosion? , 2004 .