In past decades, considerable effort has been devoted to the phenomenon of wave-induced liquefaction, because it is one of the most important factors for analysing the seabed and designing marine structures. As waves propagate and fluctuate over the ocean surface, energy is carried within the medium of the water particles. This energy could be transmitted into the seabed, which results in the r...

We present a two-dimensional vertical (2DV) flow and morphological numerical model describing the behaviour of offshore sand waves. The model contains the 2DV shallow water equations, with a free water surface and a general bed load formula. The water movement is coupled to the sediment transport equation by a seabed evolution equation. Using this model, we investigate the evolution of sand wav...

Abstract The system of seabed Cone Penetration Test (CPT) is a kind equipment for offshore investigations. Seabed CPT used to assess multiple physical properties marine sediments. Constant-rate penetration mechanism the core part CPT, which adopts dual-cylinder drive penetrate probe rod into seafloor sediments at constant speed (2cm/s). At present, domestic and its almost all rely on imports. I...

We report evidences of active seabed doming and gas discharge few kilometers offshore from the Naples harbor (Italy). Pockmarks, mounds, and craters characterize the seabed. These morphologies represent the top of shallow crustal structures including pagodas, faults and folds affecting the present-day seabed. They record upraise, pressurization, and release of He and CO2 from mantle melts and d...

Deep waters (c. 4200m) around the Crozet Islands have localised and isolated seabed communities on sediments lying beneath highly productive waters to the north and east of the Islands. The restricted areas of primary productivity are stimulated by natural iron fertilization from the volcanic islands, in an otherwise low productivity HNLC (High Nutrient Low Chlorophyll) region, characteristic o...

This paper applies Bayesian inversion to bottom-loss data derived from wind-driven ambient noise measurements from a vertical line array to quantify the information content constraining seabed geoacoustic parameters. The inversion utilizes a previously proposed ray-based representation of the ambient noise field as a forward model for fast computations of bottom loss data for a layered seabed. ...

this paper presents a k- turbulence model for simulation of steady current and itsinduced vortex shedding caused by the presence of an offshore pipeline. performance of the modelaround a circular cylinder above a wall with gap to diameter ratios of 0.1, 0.35 and 0.5 underdifferent flow regimes with reynolds numbers of 1500, 2500 and 7000 is studied. the flow field iscomputed with solving the re...

Theoretical ecology predicts that heterogeneous habitats allow more species to co-exist in a given area. In the deep sea, biodiversity is positively linked with ecosystem functioning, suggesting that deep-seabed heterogeneity could influence ecosystem functions and the relationships between biodiversity and ecosystem functioning (BEF). To shed light on the BEF relationships in a heterogeneous d...

Prediction of wave-induced instantaneous (oscillatory or momentary) liquefaction is particularly important for the design offshore foundations. Most previous studies applied linear Darcy model to characterize porous flow in a seabed. This treatment was found cause fallacious tensile stresses non-cohesive In this study, overcome such shortcomings models, non-Darcy proposed based on Karush–Kuhn–T...

Most multibeams today provide a measure of the received seabed backscatter intensity. With proper radiometric and geometric reduction, the seabed backscatter strength and its angular variation may be derived, which can then be used to attempt seabed classification. Most multibeams, however, are monochromatic in the sense that they transmit using a single center frequency (even if with some puls...