Time Dependence of Infrasonic Ambient Seafloor Noise on a Continental Shelf

Akal, T.; Barbagelata, Alessandro; Guidi, Guido; Snoek, Michael

doi:10.1007/978-1-4613-2201-6_73

Cited by 5 publications

(4 citation statements)

References 8 publications

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“…Noise in the ocean is typically nonstationary both in time and space [Burdick, 1984;Hodgkiss and Anderson, 1980]. The noise field varies considerably over time due to the rich variety of sources [Akal et al, 1986] and measurements made hours apart can show striking dissimilarity (as will be seen below). Sound recorded at near-bottom hydrophones is subject to additional propagation effects of local topography, seafloor heterogeneity, and intefface of the ocean-seafloor boundary.…”

Section: And Deploymentmentioning

confidence: 99%

The sound field near hydrothermal vents on Axial Seamount, Juan de Fuca Ridge

Little¹,

Stolzenbach²,

Purdy³

1990

J. Geophys. Res.

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High‐quality acoustic noise measurements were obtained by two hydrophones located 3 m and 40 m from an active hydrothermal vent on Axial Seamount, Juan de Fuca Ridge, in an effort to determine the feasibility of monitoring hydrothermal vent activity through flow noise generation. Most of the measured noise field could be attributed to ambient ocean noise sources of microseisms, distant shipping, and weather, punctuated by local ships and biological sources. Long‐period, low‐velocity, water/rock interface waves were detected with high amplitudes which rapidly decayed with distance from the seafloor. Detection of vent signals was hampered by unexpected spatial nonstationarity due to the shadowing effects of the caldera wall. No continuous vent signals were deemed significant based on a criterion of 90% probability of detection and 5% probability of false alarm. However, a small signal near 40 Hz, with a power level of 10−4Pa2/Hz was noticed on two records taken within 3 m of the Inferno black smoker. Hie frequency of this signal is consistent with predictions, and the power level suggests the occurrence of jet noise amplification due to convected density inhomogeneities.

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Section: And Deploymentmentioning

confidence: 99%

The sound field near hydrothermal vents on Axial Seamount, Juan de Fuca Ridge

Little¹,

Stolzenbach²,

Purdy³

1990

J. Geophys. Res.

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show abstract

“…Typical ambient ocean noise has been extensively studied (Urick, 1986;Burdick, 1984;Hodgkiss and Anderson, 1980;Wentz, 1962;Akal et al, 1986) but absolute levels depend on the exact location and time of sampling. Noise varies considerably depending on depth of water, weather, shipping, season, local topography and is punctuated by transient sources such as local ships and biological sources, making estimates for specific sites difficult.…”

Section: Field Observationsmentioning

confidence: 99%

“…The noise field varies considerably over time due to the rich variety of sources (Akal et al, 1986) and measurements made hours apart can show striking dissimilarity (as will be seen below). Sound recorded at near bottom hydrophones is subject to additional propagation effects of local topography, seafloor heterogeneity, and the interface of the oceanseafloor boundary.…”

Section: Review Of Ambient Ocean Noisementioning

confidence: 99%

“…Noise in the ocean is typically nonstationary both in time and space (Burdick, 1984;Hodgkiss and Anderson, 1980). The noise field varies considerably over time due to the rich variety of sources (Akal et al, 1986) and measurements made hours apart can show striking dissimilarity. Spatially, the noise field power levels can be orders of magnitude different depending on topography, water sound velocity structure, and proximity of receiver to the seafloor or sea surface (Urick, 1986;Burdick, 1984;Wentz, 1962).…”

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confidence: 99%

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