Variability in the acoustic response of shallow-water marine sediments determined by normal-incident 30-kHz and 50-kHz sound

Lambert, Douglas N.; Kalcic, Maria T.; Faas, Richard W.

doi:10.1016/s0025-3227(01)00234-1

Cited by 10 publications

(9 citation statements)

References 13 publications

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“…Attenuation of broadband Chirp signals is used for sediment classification [ Vandenplas et al , 2000; Stevenson et al , 2002; Gutowski et al , 2002]. Attenuation is frequency‐dependent, and new acoustic techniques use multifrequency methods [ Vanneste et al , 2001; Walter et al , 2002; Lambert et al , 2002; Price , 2006].…”

Section: Introductionmentioning

confidence: 99%

Multiscale analysis of waves reflected by granular media: Acoustic experiments on glass beads and effective medium theories

Gonidec

Gibert

2007

J. Geophys. Res.

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To cite this version:Yves Le Gonidec, Dominique Gibert. Multiscale analysis of waves reflected by granular media: Acoustic experiments on glass beads and effective medium theories. [1] The wavelet response is a multiscale method based on the continuous wavelet transform. We use it to characterize the acoustic reflectivity of a layer of glass beads with diameter d = 1 mm randomly arranged in water. The volumetric concentration is f ' 63% of spherical inclusions. The wavelet response is measured over a large frequency range (100 kHz f 5 MHz) where five different acoustic regimes are identified on the basis of scattering phenomena. A strong decrease in the reflectivity occurs when the wavelength of the incident wave is twice the bead diameter, a situation where lateral scattering is dominant. The energy ratio of the ballistic and the coda parts of the wavelet response reveals a clear transition from a ballistic propagation regime to a diffusion regime where multiple scattering occurs. The experimental data are explained with an effective medium theory approach: the reflectivity data in the low-frequency domain of the spanned frequency range are correctly reproduced with quasi-static models. For higher frequencies, more sophisticated models accounting for multiple scattering must be used. The high-frequency part of the experimental reflectivity curve may be explained by strong multiple scattering at the top of the glass beads located at the surface of the layer and corresponds to the optical geometric limit.Citation: Le Gonidec, Y., and D. Gibert (2007), Multiscale analysis of waves reflected by granular media: Acoustic experiments on glass beads and effective medium theories,

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Section: Introductionmentioning

confidence: 99%

Multiscale analysis of waves reflected by granular media: Acoustic experiments on glass beads and effective medium theories

Gonidec

Gibert

2007

J. Geophys. Res.

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“…Brandes et al [10] provided a Geoacoustic characterization of calcareous seabed areas in the Florida Keys. Lambert et al [11] studied the acoustic response of shallow-water marine sediments at six sites within the Ship Island Test Bed off Gulfport, Mississippi. And a comparably small number of studies dealing with bottom sediment physical properties are available from the international literature (e.g., [12][13][14]).…”

Section: Introductionmentioning

confidence: 99%

Seafloor Sediment Study from South China Sea: Acoustic & Physical Property Relationship

et al. 2015

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Seafloor sediments of different geographical areas in the southern South China Sea (continental shelf, continental slope, and Okinawa Trough) were gravity cored at 21 locations. Sound velocities (V) of the samples were measured at 15-cm increments immediately upon retrieval, and porosity, wet bulk density, and mean grain size were measured later in the laboratory. Empirical equations from previous studies were applied to predict V of sediment samples from the measured physical properties and it was found that the sound velocities derived from the existing equations did not closely match the measured sound velocities. Therefore empirical equations were reconstructed based on the measured data that represent the relationships between physical and acoustic properties of the different geographical area in the study area. Possible explanations for the discrepancies between the measured data and those of previous studies were investigated and found that physical properties, sediment types, geographical area, etc. are important factors that influence sound velocity. The empirical equations of this report should be preferred for prediction of sediment sound velocity for high-frequency acoustic experiments.

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“…But in environments rich in fine-grained sediments the interpretation of the sediment structure -especially the delineation of the mud layer -is challenging and requires measurements of sediment properties at appropriate resolution (Lambert et al, 2002;Schettini et al, 2010). Hence, additional measurements are performed with optical or acoustic sensors to derive the suspended solids concentrations (SSCs) (McAnally et al, 2007;Schettini et al, 2010;Shi et al, 1996;Teeter, 1992;Wolanski et al, 1989), non-acoustical direct devices such as cone penetration testing with pore pressure measurement (Seifert and Kopf, 2012;Seifert et al, 2008), or the coring for the ground truth (Lambert et al, 2002). The additional information aims to improve the layer delineation along a continuous vertical profile of sediment properties showing distinctive interfaces of water-mud-consolidated lakebed sediment.…”

Section: Introductionmentioning

confidence: 99%

Characterization of sediment layer composition in a shallow lake: from open water zones to reed belt areas

Kogelbauer

Loiskandl

2015

Hydrol. Earth Syst. Sci.

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Abstract. Lake sediment characterization, a prerequisite for the vulnerability assessment of lake ecosystems, demands reliable in situ methods for the characterization of the sediment layer composition. A unified characterization of lake sediments within lake ecotopes (open water, open water patches within the reed, and the reed) is still a challenge. Each ecotope is covered by different classical scientific disciplines (hydrography and terrestrial remote sensing to soil physics) with their specific characterization methods. Recently, a complementary tool that bridges the gap between land and hydrographic surveying methods was introduced. It is a non-acoustic device that combines two soil physical sensors (a capacitive sensor and a cone penetrometer) and GNSS-positioning in a measuring system (CSPS). The CSPS enables rapid in situ delineation of water-mud-consolidated lakebed interfaces. The system was successfully applied across ecotopes at the Neusiedler See, a well-mixed shallow lake rich in fine-grained sediments. The geo-referenced vertical CSPS profiles show ecotope-specific layer composition. The effects of wind-induced turbidity, particle size, and electrical conductivity were analysed. The water-mud interface was precisely delineated at the open water due to a persistent high water content gradient, equivalent to a lutocline. The penetration resistance (PR) for open water showed either a shallow and highly compacted consolidated lakebed or a consolidated lakebed with a partially compacted layer above, while in the reed the PR smoothly increased until reaching the deepest penetration depths.

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Variability in the acoustic response of shallow-water marine sediments determined by normal-incident 30-kHz and 50-kHz sound

Cited by 10 publications

References 13 publications

Multiscale analysis of waves reflected by granular media: Acoustic experiments on glass beads and effective medium theories

Multiscale analysis of waves reflected by granular media: Acoustic experiments on glass beads and effective medium theories

Seafloor Sediment Study from South China Sea: Acoustic & Physical Property Relationship

Characterization of sediment layer composition in a shallow lake: from open water zones to reed belt areas

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