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Areal seabed classification using backscatter angular response at 95kHz
(NATO. SACLANTCEN, 1997)
A sediment classification scheme is developed based on the angular response (AR) of the seabed backscatter strength. The AR is characterised based on its mean level and slope over predefined angular sectors, and the presence ...
Seabed sediment characteristics assessed geophysically: results of experiments in the Clyde Sea, Scotland
(NATO. SACLANTCEN, 1997)
Within a research programme aimed at developing in situ sediment classification methodologies, it has been demonstrated that with only limited ground truth information, sub-bottom profiler data can be inverted to produce ...
Seabed characterization by inversion of parametric sonar data: selection of the cost function
(NATO. SACLANTCEN, 1997)
A class of possible cost functions to be used in model-based estimation of bottom parameters from highfrequency backscatter signals is introduced. The cost is based on the properttes of the signal in the wavelettransformed ...
Dynamic attenuation extraction of seafloor sediments from very high resolution acoustic data
(NATO. SACLANTCEN, 1997)
An approach to acquire geophysical information of seabed sediments as derrved from acoustic attenuation rs described. Using thefrequencies corresponding to the signal power spectrum maximum and a point 3 dB below, signal ...
An experimental study of sediment discrimination using 1st and 2nd echoes
(NATO. SACLANTCEN, 1997)
Analysis of Roxann seabed classification data, at 24 kHz and 200 kHz, using co-located echosounders is presented. Timeseries backscater data gathered at the same time as the Roxann data has also been anal~sed using variations ...
High-resolution characterization of seafloor sediments for modeling acoustic backscatter
(NATO. SACLANTCEN, 1997)
Quantitative information on fine-scale sediment inhomogeneity is extremely scarce and sorely needed for developing realistic volume scattering models. To address this deficiency, we present a novel approach for sediment ...
Relating in situ shear wave velocity to void ratio and grain size for unconsolidated marine sediments
(NATO. SACLANTCEN, 1997)
Recent advances in field hardware have meant that it has become possible to measurein situ shear wave velocity in the upper few decimetres of sea floor sediment in a routine manner. It is known that shear wave velocity can ...
Source and receiver responses in boreholes
(NATO. SACLANTCEN, 1997)
This report considers the acoustic interaction between the acoustic freld rn a borehole and the elastic field in the surrounding formation. The problem with acoustic-seismic radration of energy from a source in a fluid ...
Bottom bistatic scattering: experimental results and model comparison for a carbonate sediment
(NATO. SACLANTCEN, 1997)
Bistatic scattering measurements were carried out under the Coastal Benthic Boundary Layer (CBBL) program. The results presented here are for a carbonate sand-silt-clay, and the data were collected in Februar) 1995 near ...
Sedimentological acoustics: an attempt to reduce the gap between acoustical modeling and sedimentoloogical survey
(NATO. SACLANTCEN, 1997)
A major task in shallow water acoustics is to provide pertinent geoacoustical data. The purpose of the work is to evaluate the state of the art in this field, connecting in situ sedimentological measurement and acoustical ...