Analysis of the specific features of propagation of tsunamis in the shelf zone of the basin

2012 ◽  
Vol 21 (6) ◽  
pp. 371-382
Author(s):  
S. F. Dotsenko ◽  
N. K. V. Sannikova
Keyword(s):  
Shelf Zone

scholarly journals The Study of Uranium Accumulation in Marine Bottom Sediments: Effect of Redox Conditions at the Time of Sedimentation

Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 332
Author(s):  
Nadezhda Khaustova ◽  
Yulia Tikhomirova ◽  
Svetlana Korost ◽  
Elena Poludetkina ◽  
Andrey Voropaev ◽  
...  
Keyword(s):  
Bottom Sediments ◽  
White Sea ◽  
Uranium Content ◽  
Black Shales ◽  
Redox Conditions ◽  
Source Rocks ◽  
Shelf Zone ◽  
The Black Sea ◽  
The White Sea ◽  
Run Off

To evaluate the effect of redox conditions at the sedimentation stage on uranium content and U/TOC ratio in marine source rocks, we analyzed the accumulation of uranium in modern marine bottom sediments formed in different redox conditions. The behavior of uranium from bottom sediments formed in oxidizing and sub-oxidizing settings has been studied on the sediments of the Upper Pleistocene–Holocene age accumulated in the coastal area of the White Sea (Kandalaksha Gulf). We studied the content of uranium, Eh, pH, TOC, C, H, N, and S element and isotope compositions and other parameters in two sampled columns of bottom sediments at a depth of 0–2.5 m. The composition of sediments was typical for the shelf zone where marine genesis mixes with the continental run-off. The upper layer of sediments (0–50 cm) were characterized by oxidizing conditions (Eh ~ 400 mV); with the increase in depth, redox conditions changed from oxidizing to reducing (0 ÷ 200 mV). The uranium concentration in the upper layer was 1–1.5 ppm, U/TOC ratio varied in the range of 0.8–1.1 ppmU/%TOC. The uranium content and U/TOC ratio increased up to the values of 2.6 ppm and 1.4 ppmU/%TOC at a depth of 0.5−2.5 m, respectively, but the general content of uranium in the studied environment was close to the values characterizing continental run-off. The results obtained for the White Sea sediments were compared with the sediment of the Black Sea, formed in the anoxic conditions of hydrogen sulfide contamination. In these conditions, the uranium content varied from 10 to 20 ppm. The obtained data were interpreted using thermodynamic modeling of the uranium forms in the seawater at different pH and Eh. This study demonstrated that the change of redox conditions from oxidizing to reducing leads to increased uranium content due to a decrease in uranium’s solubility in water. These results show that oxidation–reduction potential could be one of the most important factors controlling uranium content in black shales formed in the marine environment.

Acoustic tomography of dynamic processes in a sea shelf zone with the use of complex signals

2002 ◽  
Vol 48 (1) ◽  
pp. 1-7 ◽  
Author(s):  
V. A. Akulichev ◽  
V. V. Bezotvetnykh ◽  
S. I. Kamenev ◽  
E. V. Kuz’20min ◽  
Yu. N. Morgunov ◽  
...  
Keyword(s):  
Shelf Zone ◽  
Dynamic Processes ◽  
Acoustic Tomography ◽  
Complex Signals

scholarly journals Nonlinear Model of Coastal Flooding by a Highly Turbulent Tsunami

2021 ◽  
Vol 28 (4) ◽  
pp. 436-451
Author(s):  
Sergey A. Arsen’yev ◽  
Lev V. Eppelbaum
Keyword(s):  
Tsunami Wave ◽  
Exact Analytical Solution ◽  
Front Propagation ◽  
Coastal Flooding ◽  
Shelf Zone ◽  
Linear Solution ◽  
Coastal Inundation ◽  
Tsunami Wave Height ◽  
Calm Water ◽  
Frontal Boundary

AbstractWhen a tsunami wave comes from ocean and propagates through the shelf, it is very important to predict several dangerous factors: (a) maximum flooding of the coast, (b) tsunami wave height on the coast, (c) velocity of the tsunami front propagation through the coast, and (d) time of tsunami arriving at a given point in the coast and around it. In this study we study the separate case where the angle of inclination α of the seacoast is equal to zero. A linear solution of this problem is unsatisfactory since it gives an infinite rate of the coastal inundation that means the coast is flooded instantly and without a frontal boundary. In this study, we propose a principally new exact analytical solution of this problem based on nonlinear theory for the reliable recognizing these essential tsunami characteristics. The obtained formulas indicate that the tsunami wave can be stopped (or very strongly eliminated) in the shelf zone until approaching the shoreline. For this aim, it is necessary to artificially raising several dozens of bottom protrusions to the level of the calm water.

Modelling of the ecosystem of the Black-Sea shelf zone near the estuary of the Danube

2001 ◽  
Vol 11 (6) ◽  
pp. 509-524 ◽  
Author(s):  
V. A. Ivanov ◽  
S. P. Lyubartseva ◽  
N. Mikhailova ◽  
N. B. Shapiro
Keyword(s):  
Black Sea ◽  
Shelf Zone ◽  
The Black Sea

scholarly journals Diversity patterns and palaeoecology of benthic communities of the Kanosh Formation (Pogonip Group, Utah, western USA)

2020 ◽  
Vol 100 (4) ◽  
pp. 993-1006
Author(s):  
Richard Hofmann ◽  
Jan Philipp Kehl
Keyword(s):  
Great Basin ◽  
Benthic Communities ◽  
Habitat Diversity ◽  
Shelf Zone ◽  
Base Line ◽  
Benthic Assemblages ◽  
Diversity Patterns ◽  
Fine Grained ◽  
Type Area ◽  
Western Us

AbstractThe Dapingian to Darriwilian Kanosh Formation is one of the most fossiliferous units of the Pogonip Group (Great Basin, western US). It records a critical phase of the so-called Great Ordovician Biodiversification Event (GOBE) during which many marine clades diversified on lower systematic levels. However, a comprehensive palaeoecological analysis has not been presented for this unit so far. Based on newly collected material from three sections in the type area at Ibex, we reconstruct benthic marine communities, analyse diversity patterns, and discuss its significance for the GOBE. We find no differences in species’ composition across the formation with respect to brachiopods. Benthic assemblages are dominated by Shoshonorthis michaelis, alongside the presence of Anomalorthis lonensis and Anomalorthis utahensis across the whole unit. Trilobites show a more pronounced facies restriction with species of Kanoshia and Pseudomera being observed in more proximal limestone whereas Bathyurellus and Pseudoolenoides occur in fine-grained, low-energy deposits. The skeletal limestone also records abundant bioclasts of bryozoans, echinoderms, and receptaculitids, suggesting an ecologically diverse and tiered community being present in the inner shelf zone. However, most of these groups are not particularly diverse in terms of species richness. This implies that principle establishment of typical members of the “Palaeozoic Fauna” is not associated with a local diversification of clades. The comparably low habitat diversity of the Kanosh Fauna likely reflects environmental constraints such as high rates of siliclastic input. Additionally, these mainly Dapingian communities still represent a base-line fauna before the principal diversification took place.

scholarly journals Some estimates on the space scales of vortex pairs emitted from river mouths

2001 ◽  
Vol 8 (1/2) ◽  
pp. 1-7 ◽  
Author(s):  
V. P. Goncharov ◽  
V. I. Pavlov
Keyword(s):  
Point Vortex ◽  
Vortex Pair ◽  
Vortex Structures ◽  
Shelf Zone ◽  
Vortex Pairs ◽  
Polygonal Boundary ◽  
Dipole Vortex ◽  
Qualitative Classification ◽  
River Mouths

Abstract. Two-dimensional vortex pairs are frequently observed in geophysical conditions, for example, in a shelf zone of the ocean near river mouths. The main aims of the work are to estimate the space scales of such vortex structures, to analyze possible scenarios of vortex pair motion and to give the qualitative classification of their trajectories. We discuss some features of the motion of strong localized vorticity concentrations in a given flow in the presence of boundaries. The analyses are made in the framework of a 2D point vortex mo-del with an open polygonal boundary. Estimations are made for the characteristic parameters of dipole vortex structures emitted from river mouths into the open ocean.

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