Categorizing Active Marine Acoustic Sources Based on Their Potential to Affect Marine Animals

Ruppel, Carolyn D.; Weber, Thomas C.; Staaterman, Erica; Labak, Stanley; Hart, Patrick E.

doi:10.3390/jmse10091278

Cited by 9 publications

(2 citation statements)

References 42 publications

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“…This pattern may be characterized by the angle φ between the orthogonal to the sea surface and the line where the signal amplitude is half of its maximum. Ruppel et al (2022) showed that this angle is about 60˚for a three-plate directional Boomer. In similar cases, the isotropic factor a 1 (t) can produce an over-compensation and should be modified allowing for the φ angle.…”

Section: Geometrical Spreading Correctionmentioning

confidence: 99%

A workflow for processing mono‐channel Chirp and Boomer surveys

Vesnaver

Baradello

2023

Geophysical Prospecting

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Acquiring seismic data with multichannel, multiple‐streamer and even multi‐componentsystems at sea provides excellent images of the Earth. However, the cost and complexity of operations prevent their use in busy areas such as ports or in sensitive environments such as lagoons. In the latter cases, mono‐channel Chirp or Boomer systems are the most viable instruments for marine surveys. The lack of multiple offsets prevents the use of standard tools for amplitude‐versus‐offset and velocity analysis, which are necessary for the lithological characterization of rocks, especially for the shallow sediments in offshore engineering. In this paper, we present a few recent techniques that exploit the traveltime and amplitude of multiple reflections to compensate for the offset limitation, including a new algorithm for the joint tomographic inversion of direct arrivals, primaries and multiples. We have developed a cost‐effective workflow for mono‐channel surveys based on a data‐driven, physically consistent philosophy that attempts to approximately extract lithological parameters, such as P velocity, anelastic absorption, acoustic impedance and even density. We applied the proposed workflow to a real field experiment and obtained a semi‐quantitative estimate for shallow sediments that can be used by offshore engineers.

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Section: Geometrical Spreading Correctionmentioning

confidence: 99%

A workflow for processing mono‐channel Chirp and Boomer surveys

Vesnaver

Baradello

2023

Geophysical Prospecting

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“…Multi-channel seismic profiling or, even better, using ocean-bottom cables [1] can provide high-resolution images over wide areas [2,3]; however, the associated costs can only be borne for large-scale projects such as the construction of platforms for oil and gas exploration [4] or large wind farms [5][6][7][8]. For smaller engineering projects in high-traffic areas such as harbors [9], archeological areas [10] or sensitive environments [11][12][13], the low cost and ease of use of Boomer surveys may be the only viable option [14][15][16][17][18][19][20]. For monochannel systems, the estimation of rock parameters such as P velocity, density and thickness of shallow marine sediments becomes a challenge.…”

Section: Introductionmentioning

confidence: 99%

Coupled Inversion of Amplitudes and Traveltimes of Primaries and Multiples for Monochannel Seismic Surveys

Vesnaver,

Baradello

2024

JMSE

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Engineers need to know properties of shallow marine sediments to build piers, pipelines and even offshore windfarms. We present a method for estimating the density, P velocity and thickness of these sediments. The traveltime inversion of primary and multiple reflections enables their semiquantitative estimation in marine surveys when using a minimal acquisition system such as a monochannel Boomer. Picking errors, ambient noise and interfering events lead to significant errors in the estimates. Similar, albeit milder, instabilities occur when inverting the signal amplitudes to determine the reflectivity of the layer interfaces. In this paper, we introduce a coupling between the separate inversion of amplitudes and traveltimes to obtain a better Earth model. The P velocity shows up in two stable terms provided by the separate inversions: the acoustic impedance of shallow sediments (through the amplitudes) and the transit time across the sediment layer (through the traveltimes). We couple the two inversion engines by imposing a smoothness condition on velocity and density and thickness of the layer while keeping the impedance and traveltime constant. We thus exploit the ambiguity of the solution to introduce geological criteria and reduce the noise contribution. We validated the proposed method with synthetic and real data.

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Current species protection does not serve its porpoise—Knowledge gaps on the impact of pressures on the Critically Endangered Baltic Proper harbour porpoise population, and future recommendations for its protection

Koschinski,

Owen,

Lehnert

et al. 2024

Ecology and Evolution

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Successful management requires information on pressures that threaten a species and areas where conservation actions are needed. The Baltic Proper harbour porpoise population was first listed as Critically Endangered by the International Union for the Conservation of Nature in 2008. Now, 16 years later, there is no change in conservation status despite ample conservation policy calling for its protection and an urgent need for management action to protect this population. Here, we provide an overview of the current status of the population, highlight knowledge gaps on the impact of pressures, and make recommendations for management of anthropogenic activities. Based on an exceeded limit for anthropogenic mortality, the high concentrations of contaminants in the Baltic Sea, combined with reductions in prey availability and increases in underwater noise, it is inferred that this population is likely still decreasing in size and conservation action becomes more urgent. As bycatch and unprotected underwater explosions result in direct mortality, they must be reduced to zero. Inputs of contaminants, waste, and existing and emerging noise sources should be minimised and regulated. Additionally, ecosystem‐based sustainable management of fisheries is paramount in order to ensure prey availability, and maintain a healthy Baltic Sea. Stranding networks to routinely assess individuals for genetic population assignment and health need to be expanded, to identify rare samples from this population. Knowledge is still scarce on the population‐level impact of each threat, along with the cumulative impact of multiple pressures on the population. However, the current knowledge and management instruments are sufficient to apply effective protection for the population now. While bycatch is the main pressure impacting this population, urgent conservation action is needed across all anthropogenic activities. Extinction of the Baltic Proper harbour porpoise population is a choice: decision‐makers have the fate of this genetically and biologically distinct marine mammal population in their hands.

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Categorizing Active Marine Acoustic Sources Based on Their Potential to Affect Marine Animals

Cited by 9 publications

References 42 publications

A workflow for processing mono‐channel Chirp and Boomer surveys

A workflow for processing mono‐channel Chirp and Boomer surveys

Coupled Inversion of Amplitudes and Traveltimes of Primaries and Multiples for Monochannel Seismic Surveys

Current species protection does not serve its porpoise—Knowledge gaps on the impact of pressures on the Critically Endangered Baltic Proper harbour porpoise population, and future recommendations for its protection

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