Multi-scale slope instabilities along the Nile deep-sea fan, Egyptian margin: A general overview

Loncke, Lies; Gaullier, Virginie; Droz, Laurence; Ducassou, Emmanuelle; Migeon, Sébastien; Mascle, J.

doi:10.1016/j.marpetgeo.2008.03.010

Cited by 60 publications

(66 citation statements)

References 38 publications

(73 reference statements)

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“…1990;Frey Martinez et al 2005;Bull et al 2009). This is exemplified in the Gulf of Mexico and the Nile Delta continental slope, where channels have been captured by the headwalls of basal scars and were located within the scars (Hackbarth and Shew 1994;Winker and Booth 2000;Loncke et al 2009;Kertznus 2009;Kneller et al 2016).…”

Section: Depletion Zone Of the Basal Scar And Flow Capturementioning

confidence: 99%

The Role of Mass Wasting In the Progressive Development Of Submarine Channels (Espírito Santo Basin, Se Brazil)

Qin

Alves

Constantine

et al. 2017

Journal of Sedimentary Research

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ABSTRACT:A Pliocene-Quaternary submarine channel system, influenced by a localized mass wasting, is investigated in this work using high-resolution 3D seismic data from offshore Espírito Santo Basin, SE Brazil. Three abandoned channels, a channel belt and an mass-transport deposit (MTD) are recognized in the channel system within a confluence region confined by salt diapirs. In this confluence region, the cross-sectional area (CSA) of the channel system can be up to 1.2 km 2 , i.e., 4 to 10 times larger than CSA in other parts of the channel system. Such significant changes in the architecture and morphology of the channel system resulted from the interaction between mass-wasting processes and turbidity flows. We postulate that a basal erosional scar was created by mass-wasting processes and was filled with an MTD. This basal scar was then used as a preferential pathway for turbidity flows, which were captured by its headwall and lateral margins. The interpreted data shows that the captured turbidity flows greatly widened the basal scar, but caused only small modifications in scar height. Part of the MTD within the basal scar was removed downslope by turbidity flows, and was replaced by channel-fill deposits. This paper shows a flow-capture process occurred in a confluence region on continental slope. Basal scars can capture turbidity flows and facilitate flow channelization, which is a key process for submarine-channel initiation. The replacement of MTD by channel-fill deposits has profound implications for reservoir volumes and net-to-gross ratios in channel systems and partly depends on the turbidity-flows properties, such as their erosive ability and frequency. The more erosive and frequent flows are captured by the basal scar, the larger is the accommodation space created for succeeding sand-prone turbidites.

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Section: Depletion Zone Of the Basal Scar And Flow Capturementioning

confidence: 99%

The Role of Mass Wasting In the Progressive Development Of Submarine Channels (Espírito Santo Basin, Se Brazil)

Qin

Alves

Constantine

et al. 2017

Journal of Sedimentary Research

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“…According to the geological data, this landslide generated a tsunami wave with a height of 10-12 m on the coast of Norway; on the Shetland Islands, it was higher than 20 m [13]. Many other examples exist in the geological record and are often observed on industry-acquired geophysical data [14][15][16]. The common features of the above landslides are that they are very long (10 1 -10 2 km), relatively shallow (less than 10 2 m thick) and occur in very mild continental slopes (inclination less than 10 −1 ) built of normally consolidated sediments.…”

Section: Introduction (A) Submarine Landslidesmentioning

confidence: 99%

Significance of the actual nonlinear slope geometry for catastrophic failure in submarine landslides

Puzrin

Gray²,

Hill

2015

Proc. R. Soc. A.

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A simple approach to slope stability analysis of naturally occurring, mild nonlinear slopes is proposed through extension of shear band propagation (SBP) theory. An initial weak zone appears in the steepest part of the slope where the combined action of gravity and seismic loads overcomes the degraded peak shear resistance of the soil. If the length of this steepest part is larger than the critical length, the shear band will propagate into the quasi-stable parts of the slope, where the gravitational and seismically induced shear stresses are smaller than the peak but larger than the residual shear strength of the soil. Growth of a shear band is strongly dependent on the shape of the slope, seismic parameters and the strength of soil and less dependent on the slope inclination and the sensitivity of clay. For the slope surface with faster changing inclination, the criterion is more sensitive to the changes of the parameters. Accounting for the actual nonlinear slope geometry eliminates the main challenge of the SBP approach-determination of the length of the initial weak zone, because the slope geometry can be readily obtained from submarine site investigations. It also helps to identify conditions for the early arrest of the shear band, before failure in the sliding layer or a change in loading or excess pore water pressures occurs. The difference in the size of a landslide predicted by limiting equilibrium and SBP approaches can reach orders of magnitude, potentially providing an explanation for the immense dimensions of many observed submarine landslides that may be caused by local factors acting over a limited portion of the slope.

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“…These processes can also induce hazards including tsunami [McAdoo and Watts, 2004], and the destruction of coastal communities [Mulder et al, 1994;Dan et al, 2007] and offshore infrastructure, such as submarine cables [Piper et al, 1999]. Several factors can initiate submarine slope failures: overpressure caused by high rates of sediment input from rivers, deltas, or glaciers [Prior and Suhayda, 1979;Loncke et al, 2009]; accumulation of excess pore pressure due to gas hydrate dissociation [McIver, 1982;Field, 1990;Bouriak et al, 2000;Leynaud et al, 2009]; earthquake-induced ground motion and liquefaction [Piper et al, 1999;Tappin et al, 2001]; slope oversteepening caused by tectonic tilting of the substrate [Strasser et al, 2011;Jackson, 2012]; volcanic eruption [Masson et al, 2002;Satake, 2007]; and seepage [Orange et al, 1997]. These triggers reduce the resistance of the slope and/or increase the forces applied to the slope sediments.…”

Section: Introductionmentioning

confidence: 99%

Mass transport‐dominated sedimentation in a foreland basin, the Hidaka Trough, northern Japan

Noda

TuZino

Joshima

et al. 2013

Geochem Geophys Geosyst

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[1] Mass transport is an important process of sediment redistribution from shallow to deep sea basins. It is vital to understand this process for disaster prevention and protection of economic interests in coastal and offshore areas. We describe mass transport-dominated sedimentation in an active foreland basin, the Hidaka Trough, which developed from collision between the northeastern Japan arc and the Kuril arc. The basin is deformed by east-west compression associated with large, frequent earthquakes. The trough is filled with thick (>4.5 km) sediments, ranging from coal-bearing Cretaceous terrestrial strata to modern diatomaceous hemipelagic mud and volcanic ash. Bottomsimulating reflectors and the distribution of mud volcanoes, pockmarks, and acoustic wipe-out zones on the seismic records suggest the presence of subsurface gases in the sediments. The basin features stacked mass transport deposits (MTDs), but no channel-levee systems have developed. The MTDs are relatively thin (<30 m) and are derived from three sides of the basin margin. Initiation of submarine slope failure in this area may be controlled by multiple factors that increase driving forces and decrease resistance of the slopes. The driving forces include oversteepening of the margin slope as a result of thrusting and folding, and additional downslope gravitational acceleration caused by cyclic shaking during earthquakes. Decreased resistance in the slopes may be caused by the accumulation of excess pore-water pressure driven by a high-sedimentation rate, gas hydrate dissociation accompanying changes in sea level or seawater temperature, and liquefaction in coarsegrained beds during earthquakes.

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Multi-scale slope instabilities along the Nile deep-sea fan, Egyptian margin: A general overview

Cited by 60 publications

References 38 publications

The Role of Mass Wasting In the Progressive Development Of Submarine Channels (Espírito Santo Basin, Se Brazil)

The Role of Mass Wasting In the Progressive Development Of Submarine Channels (Espírito Santo Basin, Se Brazil)

Significance of the actual nonlinear slope geometry for catastrophic failure in submarine landslides

Mass transport‐dominated sedimentation in a foreland basin, the Hidaka Trough, northern Japan

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