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AbstractSubmarine landslides are a critical geological process that significantly influences seafloor stability and geological evolution, making them a focal point of geological disaster research. Particularly, rapid sedimentation as a crucial preconditioning factor for submarine landslide initiation is increasingly recognized in contemporary research. However, no comprehensive review currently examines the correlation between rapid sedimentation and submarine landslides. To elucidate the interaction mechanisms between submarine landslides and rapid sedimentation and to provide a new theoretical foundation for the prediction and prevention of geological hazards, the study categorizes three primary sedimentation patterns in marine environments and establishes a detailed historical database of sedimentation-related submarine landslide events. Moreover, the paper systematically reviews and critiques the existing research methods and advancements in addressing rapid sedimentation-related submarine landslides, and a bibliometric analysis of recent research progress is conducted. Finally, the study highlights several challenges in the study of rapid sedimentation and proposes future recommendations, aiming to provide robust support for the in-depth investigation of submarine landslides. [ABSTRACT FROM AUTHOR]

The offshore Campos Basin, located in Southeastern Brazil represents an important area in the Brazilian economy as it is one of the most prolific oil-producing basins in the country. With the development of offshore infrastructures in this region, structural design and location must consider different geohazards. This paper addresses the seismic response of gentle submarine slopes subjected to small-to-moderate-sized earthquakes, representative of the Brazilian seismic conditions. The seismic analyses employed numerical modeling, with a nonlinear constitutive model. A set of bedrock ground motions representative of the offshore Campos Basin seismicity was obtained, employing a Uniform Hazard Response spectrum for the region and earthquakes from the Pacific Earthquake Engineering Research (PEER) database. Numerical modelling results showed that, even for small slope angles and moderate earthquakes, there is an accumulation of permanent displacements and shear strains in the downslope direction can affect the stability and performance of existing offshore infrastructures. The findings of this research provide a valuable reference for the prediction of seismic displacements, shear strains and seabed amplification or attenuation of earthquakes on gentle slopes in deep-water deposits similar to those found in the offshore Campos Basin. [ABSTRACT FROM AUTHOR]

Submarine telecommunication cables, which carry about 99% of international telecommunications, are usually buried shallowly beneath seabed and vulnerable to seabed movements. In recent years, many submarine cable damages have been observed when significant lateral seabed movements occur due to geohazards, e.g., offsets of strike-slip faults and submarine landslides. However, research on the interaction between submarine telecommunication cables and lateral seabed movements is limited. There is no existing method for evaluating the cable safety when subjected to lateral seabed movements. This paper aims to carry out finite element (FE) analysis and physical modeling to investigate the responses of submarine telecommunication cables to lateral seabed movements. A FE model is developed and validated by full-scale physical test results. After validation of the FE model, a series of parametric studies is performed covering typical ranges of soil properties, cable burial depths, cable characteristics and seabed movement characteristics. The parametric study results are summarized in a dimensionless plot, followed by a regression analysis. A simple but effective formula is proposed to predict the maximum cable strains induced by lateral seabed movements. The dominant parameters that control submarine cable responses are identified and incorporated into the formula. Safety criteria for submarine telecommunication cables are also proposed for evaluating the cable safety when subjected to lateral seabed movements. [ABSTRACT FROM AUTHOR]

Submarine pipelines are likely to be impacted by frequently catastrophic landslides, resulting in broken pipelines and causing irreversible economic losses; however, because pipelines located in deep-sea environments are simply laid atop the seabed, effective protective measures have not yet been proposed. In this paper, a pipeline with a uniform distribution of honeycomb holes on the surface, namely, a honeycomb-hole submarine pipeline, is discussed and optimized in detail. A computational fluid dynamics (CFD) approach is verified and improved several times and then applied to conduct 120 numerical simulations for 12 types of suspended submarine pipelines under 10 conditions covering the Reynolds number range required by the project conditions. First, the typical characteristics of the impact forces acting on pipelines in a seawater environment are systematically investigated, and the peak drag force is isolated as the most dangerous load caused by a landslide impact. Second, according to the formation and reduction mechanism of the drag force, it is proposed that a honeycomb-hole submarine pipeline can effectively delay the separation of the boundary layer, reduce the impact velocity, prolong the arrival time, and decrease the differential pressure drag force. Finally, two normalized parameters, the depth ratio and area ratio, are established to develop an optimization design methodology, and the optimal design values of honeycomb-hole pipelines are achieved under the support of limited data. This work presents a protective technology for submarine pipelines and provides new insights into the response of fluid-structure interactions. [ABSTRACT FROM AUTHOR]