Mechanism for sea bottom reverberation in long range sonar in a range‐dependent continental shelf environment

AbstractThe seaward extension of onshore formations and structures were previously almost unknown in Provence. The interpretation of 2D high-resolution marine seismic profiles together with the integration of sea-bottom rock samples provides new insights into the stratigraphic, structural and paleogeographic framework of pre-Messinian Salinity Crisis (MSC) deposits of the Provence continental shelf. Seven post-Jurassic seismic units have been identified on seismic profiles, mapped throughout the offshore Provence area and correlated with the onshore series. The studied marine surface and sub-surface database provided new insights into the mid and late Cretaceous paleogeography and structural framework as well as into the syn- and post-rift deformation in Provence. Thick (up to 2000 m) Aptian-Albian series whose deposition is controlled by E-W-trending faults are evidenced offshore. The occurrence and location of the Upper Cretaceous South-Provence basin is confirmed by the thick (up to 1500 m) basinal series downlaping the Aptian-Albian unit. This basin was fed in terrigenous sediments by a southern massif (“Massif Méridional”) whose present-day relict is the Paleozoic basement and its sedimentary cover from the Sicié imbricate. In the bay of Marseille, thick syn-rift (Rupelian to Aquitanian) deposition occurred (>1000 m). During the rifting phase, syn-sedimentary deformations consist of dominant N040 to N060 sub-vertical faults with a normal component and N050 drag-synclines and anticlines. The syn-rift and early post-rift units (Rupelian to early Burdigalian) are deformed and form a set of E-W-trending en echelon folds that may result from sinistral strike-slip reactivation of N040 to N060 normal faults during a N-S compressive phase of early-to-mid Burdigalian age (18–20 Ma). Finally, minor fault reactivation and local folding affect post-rift deposits within a N160-trending corridor localized south of La Couronne, and could result from a later, post-Burdigalian and pre-Pliocene compressive phase.

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The Lateral Boundaries of the Continental Shelf and the Judgment of the International Court of Justice in the North Sea Continental Shelf Cases

The American Journal of International Law ◽

10.2307/2199204 ◽

1970 ◽

Vol 64 (3) ◽

pp. 562-593 ◽

Cited By ~ 6

Author(s):

Etienne Grisel

Keyword(s):

Continental Shelf ◽

International Law ◽

International Court Of Justice ◽

Customary International Law ◽

Exclusive Jurisdiction ◽

The North ◽

Sea Bottom ◽

International Court ◽

The North Sea ◽

Recent Origin

A rule of customary international law of recent origin has conferred sovereign rights over the continental shelf to individual states for the limited purposes of exploration and exploitation. The attribution of such exclusive jurisdiction required the delimitation of boundaries between the submarine areas appertaining to various littoral states. The importance of such partition of the seabed and subsoil is self-evident, but two points do call for comment. First, since the shelf may be considerably extended in the future according to the criterion of exploitability, the method now adopted will have a constantly growing significance. Second, the acquisition of the sea bottom by coastal nations has created inequalities between them, depending on their relative degree of technical development as well as on their geographical circumstances. The drawing of boundaries separating their respective shelves can aggravate or diminish these inequalities.

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Fish schools are the dominant cause of long‐range active sonar clutter in the New Jersey Continental Shelf: Quantitative correlations

The Journal of the Acoustical Society of America ◽

10.1121/1.4777402 ◽

2003 ◽

Vol 114 (4) ◽

pp. 2375-2375 ◽

Cited By ~ 1

Author(s):

Deanelle T. Symonds ◽

Purnima Ratilal ◽

Redwood W. Nero ◽

Nicholas C. Makris

Keyword(s):

New Jersey ◽

Continental Shelf ◽

Long Range ◽

Fish Schools ◽

Active Sonar

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Evidence that the Deepwater Horizon Oil Spill Caused a Change in the Nickel, Chromium, and Lead Average Seasonal Concentrations Occurring in Sea Bottom Sediment Collected from the Eastern Gulf of Mexico Continental Shelf Between the Years 2009 and 2011

Water Air & Soil Pollution ◽

10.1007/s11270-013-1756-1 ◽

2013 ◽

Vol 224 (11) ◽

Cited By ~ 10

Author(s):

David A. Steffy ◽

Alfred C. Nichols ◽

L. Joe Morgan ◽

Rachael Gibbs

Keyword(s):

Gulf Of Mexico ◽

Continental Shelf ◽

Bottom Sediment ◽

Oil Spill ◽

Deepwater Horizon ◽

Deepwater Horizon Oil Spill ◽

Nickel Chromium ◽

Sea Bottom ◽

Eastern Gulf Of Mexico

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Nonreciprocity of long‐range reverberation in a wedged continental shelf.

The Journal of the Acoustical Society of America ◽

10.1121/1.403488 ◽

1992 ◽

Vol 91 (4) ◽

pp. 2343-2343 ◽

Cited By ~ 1

Author(s):

Ji‐xun Zhou ◽

Xue‐zhen Zhang ◽

Dinghua Guan

Keyword(s):

Continental Shelf ◽

Long Range

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Morfologia e Sedimentologia da Plataforma Continental Interna entre as Praias Porto de Galinhas e Campos - Litoral Sul de Pernambuco, Brasil

Pesquisas em Geociências ◽

10.22456/1807-9806.19587 ◽

2003 ◽

Vol 30 (2) ◽

pp. 17 ◽

Cited By ~ 17

Author(s):

VALDIR DO AMARAL VAZ MANSO ◽

IRAN CARLOS STALLIVIERE CORRÊA ◽

NÚBIA GUERRA

Keyword(s):

Continental Shelf ◽

Coastal Zone ◽

South Coast ◽

Sea Bottom ◽

Inner Continental Shelf

The analysis of geomorphic and sedimentological characteristics of the inner continental shelf is an important propriety to studies of the coastal zone since they inform the conditions of the sea bottom, the predominant features and the types of associated sediments. Associated to morfodinamic study it can, for example, identify predisposed areas to erosive processes. The present paper shows the batimetry (to -20m) and the sediments distribution in the inner continental shelf between Porto de Galinhas and Campos beaches, south coast of Pernambuco State. The work results constitute pioneering mark in the inner continental shelf of the Pernambuco state.

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Spatio-Temporal Assessment of the European Hake (Merluccius merluccius) Recruits in the Northern Iberian Peninsula

Frontiers in Marine Science ◽

10.3389/fmars.2021.614675 ◽

2021 ◽

Vol 8 ◽

Author(s):

Francisco Izquierdo ◽

Iosu Paradinas ◽

Santiago Cerviño ◽

David Conesa ◽

Alexandre Alonso-Fernández ◽

...

Keyword(s):

Continental Shelf ◽

Iberian Peninsula ◽

Environmental Variables ◽

Temporal Dynamics ◽

Bottom Temperature ◽

Merluccius Merluccius ◽

Sea Bottom ◽

Temporal Models ◽

Spatio Temporal ◽

European Hake

The protection of fish nurseries has been recognized as a useful tool to efficiently manage fisheries given that protected areas enhance the recruitment of target species. To identify and locate potential nursery areas, a solid understanding of species-environment relationships and their spatio-temporal dynamics is needed. Within this context, in this study we assess where European hake (Merluccius merluccius) recruits persistently aggregate in the northern continental shelf of the Iberian Peninsula. Hake recruit data collected during scientific trawl surveys between 2005 and 2016 were analyzed using Bayesian hurdle hierarchical spatio-temporal models, considering the environmental variables bathymetry, sea bottom temperature and salinity. Additionally, three different spatio-temporal structures (i.e., persistent, progressive, or opportunistic) were compared to assess the temporal persistence of nurseries over time. Among all the environmental variables analyzed, bathymetry was the most important. The preferential habitat of recruits was found to be within a bathymetric range of 120–200 m. Our findings clearly show that there is a temporally persistent main nursery located along the continental shelf of the Artabrian gulf (off La Coruña) in addition to several areas with high aggregations of hake recruits but with strong inter-annual variability. We argue that the analytical framework applied in this study allowed us to identify European hake nurseries in the northern continental shelf of the Iberian Peninsula, as well as their spatio-temporal fluctuations throughout the study period (2005–2016), and to assess which environmental factors, among bathymetry, sea bottom temperature and salinity, influence the occurrence and abundance of recruits in the study area. Results of our models also produce a new abundance index that could be useful for improving traditional stock assessment models.

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Anthropogeomorphology of marine fisheries in India: understanding the critical roles of Marine Fishery Advisories towards achieving SDG 14

10.5194/egusphere-egu21-2250 ◽

2021 ◽

Author(s):

Sudip Kumar Kundu ◽

Harini Santhanam

Keyword(s):

Continental Shelf ◽

Marine Environment ◽

Search Time ◽

Marine Fisheries ◽

Anthropogenic Pressures ◽

The Sustainable Development ◽

Marine Fishery ◽

Iuu Fishing ◽

Sea Bottom ◽

Marine Fishing

<p>The livelihoods of more than 30 per cent of the total population in India residing in nine maritime states and four Union Territories are dependent on the diverse ecosystem services offered by coastal and marine systems. Marine fisheries contribute significantly to the Indian economy through the foreign exchange from the export of seafood which corresponds to nearly 5 per cent of the overall export and 20 per cent of the agro-export. In recent times, the anthropogenic pressures due to extensive marine fishing introduce challenges in the marine environment. Marine anthropogeomorphology, capable of transforming the natural settings of the continental shelf dominantly, is often not studied in detail from the perspective of sustainable fishing. For example, the use of the assorted fishing gears can damage the sea floor, apart from the capture of juvenile and non-target fishes. Bottom trawling by mechanised crafts as a part of marine fishing affects the geomorphology of the continental shelf and continental slope by displacing boulders, interrupting the structure of the sediment column, resuspending sediments, and imprinting deep holes on the muddy sea bottom. Occasionally, the abandoned fishing nets/gears on the seafloor are also responsible for the geomorphological damages to the bottom of the sea and death of several marine benthic flora and fauna, a phenomenon referred to as &#8216;ghost fishing&#8217;. Further, Illegal, Unreported and Unregulated (IUU) fishing in the ocean also poses major threats for the marine environment. Thus, it is essential to quantify these impacts of anthropogeomorphology in order to achieve the targets of the Sustainable Development Goal (SDG) 14, promulgated by the United Nations Organisation. Marine Fishery Advisories, especially, Potential Fishing Zones (PFZ) advisories may be helpful in reducing the impacts by aiding sustainable harvesting of pelagic fishes under the current scenario. The ESSO-Indian National Centre for Ocean Information Services (INCOIS) is the nodal agency, which disseminates PFZ advisory since 1999 using remotely sensed datasets of sea surface temperature and chlorophyll-a to reduce the uncertainty during marine fishing. PFZ advisory can help to promote environment-friendly fishing by reducing the search time and hence, ensuring minimal damage to the marine environment.</p>

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