Attenuation of sound in marine sediments: A review with emphasis on new low-frequency data

Kibblewhite, A. C.

doi:10.1121/1.398195

Cited by 113 publications

(65 citation statements)

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“…We are not, however, convinced that dispersion, as predicted by Biot^Stoll models (e.g., Yamamoto and Turgut, 1988;Leurer, 1997) and concluded from data presented by others (Stoll, 1989;Kibblewhite, 1989;Bowles, 1997;Ba⁄, 1999) produces di¡erences of the observed magnitude in Eel margin sediments. While attenuation is much more di⁄cult to measure than sound speed because of its sensitivity to noise and transducer response, these limitations should not produce the distinct di¡erences that we see in our data.…”

Section: Attenuationmentioning

confidence: 59%

“…The dispersive behavior of elastic wave propagation through porous media was theoretically predicted (Biot, 1956a,b;Kjartansson, 1979), and reported for sound speed in sandy sediments (Barbagelata et al, 1991;Fu, 1998). Other researchers doubt the existence of dispersion in marine sediments or argue that the e¡ect may be so small over a wide frequency band that it can be neglected (Hamilton, 1972;Kibblewhite, 1989;Bowles, 1997;Buckingham, 1997).…”

Section: Di¡erences Between In Situ Acoustic and Laboratory Ultrasonimentioning

confidence: 99%

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In situ acoustic and laboratory ultrasonic sound speed and attenuation measured in heterogeneous soft seabed sediments: Eel River shelf, California

Gorgas

Wilkens

et al. 2002

Marine Geology

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We compared in situ and laboratory velocity and attenuation values measured in seafloor sediments from the shallow water delta of the Eel River, California. This region receives a substantial volume of fluvial sediment that is discharged annually onto the shelf. Additionally, a high input of fluvial sediments during storms generates flood deposits that are characterized by thin beds of variable grain-sizes between the 40-and 90-m isobaths. The main objectives of this study were (1) to investigate signatures of seafloor processes on geoacoustic and physical properties, and (2) to evaluate differences between geoacoustic parameters measured in situ at acoustic (7.5 kHz) and in the laboratory at ultrasonic (400 kHz) frequencies. The in situ acoustic measurements were conducted between 60 and 100 m of water depth. Wet-bulk density and porosity profiles were obtained to 1.15 m below seafloor (m bsf) using gravity cores of the mostly cohesive fine-grained sediments across-and along-shelf. Physical and geoacoustic properties from six selected sites obtained on the Eel margin revealed the following. (1) Sound speed and wet-bulk density strongly correlated in most cases. (2) Sediment compaction with depth generally led to increased sound speed and density, while porosity and in situ attenuation values decreased. (3) Sound speed was higher in coarser-than in finer-grained sediments, on a maximum average by 80 m s 31 . (4) In coarse-grained sediments sound speed was higher in the laboratory (1560 m s 31 ) than in situ (1520 m s 31 ). In contrast, average ultrasonic and in situ sound speed in finegrained sediments showed only little differences (both approximately 1480 m s 31 ). (5) Greater attenuation was commonly measured in the laboratory (0.4 and 0.8 dB m 31 kHz 31 ) than in situ (0.02 and 0.65 dB m 31 kHz 31 ), and remained almost constant below 0.4 m bsf. We attributed discrepancies between laboratory ultrasonic and in situ acoustic measurements to a frequency dependence of velocity and attenuation. In addition, laboratory attenuation was most likely enhanced due to scattering of sound waves at heterogeneities that were on the scale of

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Section: Attenuationmentioning

confidence: 59%

Section: Di¡erences Between In Situ Acoustic and Laboratory Ultrasonimentioning

confidence: 99%

In situ acoustic and laboratory ultrasonic sound speed and attenuation measured in heterogeneous soft seabed sediments: Eel River shelf, California

Gorgas

Wilkens

et al. 2002

Marine Geology

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“…In this case the model is about 12 km thick. The seafloor consisted of ͑i͒ a 20 m thick layer of homogeneous sediment with Vp = 1.6 km/ s and attenuation of 0.01 dB/ m at 70 Hz ͓all attenuation values are from Hamilton ͑1976͒, although better values for sediments have been recommended in more recent papers ͑Bowles, 1997; Kibblewhite, 1989;Mitchell and Focke, 1980͔͒, ͑ii͒ a 2 km thick layer of basalt with a gradient in P-wave speed from 4.0 to 6.8 km/ s and attenuation of 0.0025 dB/ m, ͑iii͒ a 4 km thick layer of gabbro with a gradient in P-wave speed from 6.8 to 8.1 km/ s and attenuation of 0.0025 dB/ m, and ͑iv͒ a homogeneous half-space for the mantle at 8.1 km/ s and attenuation of 0.0025 dB/ m. Density in the sediments ͑mostly pelagic clay͒ is given by: density ͑g / cc͒ = 1.35 + ͑1.80− 1.35͒ / 300ϫ depth ͑m͒ ͑Hamilton, 1976͒. For the igneous rocks density is related to compressional sound speed by: density ͑g / cc͒ = 1.91+ 0.158Vp ͑km/ s͒ ͑Swift et al, 1998͒.…”

Section: F Parabolic Equation "Pe… Modelingmentioning

confidence: 99%

Deep seafloor arrivals: An unexplained set of arrivals in long-range ocean acoustic propagation

Stephen

Bolmer

Dzieciuch

et al. 2009

The Journal of the Acoustical Society of America

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Receptions, from a ship-suspended source ͑in the band 50-100 Hz͒ to an ocean bottom seismometer ͑about 5000 m depth͒ and the deepest element on a vertical hydrophone array ͑about 750 m above the seafloor͒ that were acquired on the 2004 Long-Range Ocean Acoustic Propagation Experiment in the North Pacific Ocean, are described. The ranges varied from 50 to 3200 km. In addition to predicted ocean acoustic arrivals and deep shadow zone arrivals ͑leaking below turning points͒, "deep seafloor arrivals," that are dominant on the seafloor geophone but are absent or very weak on the hydrophone array, are observed. These deep seafloor arrivals are an unexplained set of arrivals in ocean acoustics possibly associated with seafloor interface waves.

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“…The physical parameters included seismic velocities and attenuation, mud densities and porosities, and sedimentary thickness to bedrock. In addition, the field parameters were complemented by estimates taken from the literature (Hamilton, 1971(Hamilton, , 1972(Hamilton, , 1976Stoll, 1985;Kibblewhite, 1989) that are typical for these types of bay mud (clayey silts, and silty clays). The physical parameters were determined as: These physical parameters were subsequently taken to build numerical models for wave propagation simulations using FD and analytical modeling.…”

Section: Task 1: Determination Of Modeling Parameters At Mare Island Camentioning

confidence: 99%

Seismic Imaging of UXO-Contaminated Underwater Sites (Interim Report)

Gritto¹,

Korneev²,

Nihei³

et al. 2004

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SummaryFinite difference modeling with 2-dimensional models were conducted to evaluate the performance of source-receiver arrays to locate UXO in littoral environments. The model parameters were taken from measurements in coastal areas with typical bay mud and from examples in the literature. Seismic arrays are well suited to focus energy by steering the elements of the array to any point in the medium that acts as an energy source. This principle also applies to seismic waves that are backscattered by buried UXO. The power of the array is particularly evident in strong noise conditions when the signal-to-noise ratio is too low to observe the scattered signal on the seismograms. Using a seismic array, it was possible to detect and locate the UXO with a reliability similar to noise free situations. When the UXO was positioned within 3-6 wavelengths of the incident signal from the source array, the resolution was good enough to determine the dimensions of the UXO from the scattered waves. Beyond this distance this distinction decreased gradually while the location and the center of the UXO were still determined reliably. The location and the dimensions of two adjacent UXO were resolved down to a separation of 1/3 of the dominant wavelength of the incident wave, at which time interference effects began to appear. In the investigated cases, the ability to locate a UXO was independent on the use of a model with a rippled or a flat seafloor, as long as the array was located above the UXO. Nevertheless, the correct parameters of the seafloor interface were obtained in these cases. An investigation to find the correct migration velocity in the sediments to locate the UXO revealed that a range of velocity gradients centered around the correct velocity model produced comparable results, which needs to be further investigated with physical modeling.

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Attenuation of sound in marine sediments: A review with emphasis on new low-frequency data

Cited by 113 publications

References 1 publication

In situ acoustic and laboratory ultrasonic sound speed and attenuation measured in heterogeneous soft seabed sediments: Eel River shelf, California

In situ acoustic and laboratory ultrasonic sound speed and attenuation measured in heterogeneous soft seabed sediments: Eel River shelf, California

Deep seafloor arrivals: An unexplained set of arrivals in long-range ocean acoustic propagation

Seismic Imaging of UXO-Contaminated Underwater Sites (Interim Report)

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