Triggering and Evolution of a Giant Submarine Landslide, Offshore Angola, Revealed by 3D Seismic Stratigraphy and Geomorphology

Gee, M.J.R.; Gawthorpe, Robert L.; Friedmann, S. Julio

doi:10.2110/jsr.2006.02

Cited by 113 publications

(90 citation statements)

References 26 publications

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“…6) and downslope direction, suggesting an eastward flow direction. Similar structures observed on the Tampen slide (although on a completely different scale) are interpreted as deformed translated blocks (Frey-Martinez et al, 2005;Gee et al, 2006).…”

Section: Sss Ivcsupporting

confidence: 54%

“…The long-axis orientation of these coherent blocks of material, transported downslope with the main debris flow or slide body, has previously been used to infer flow direction (Frey-Martinez et al, 2005;Gee et al, 2006). This implies a northeastward dominant flow direction, which is in agreement with the package thinning.…”

Section: Sss Ivamentioning

confidence: 84%

“…Due to their extremely high hazard, most of this work has concentrated on large-to medium-scale structures originating on active (e.g., Tappin et al, 2007) and passive (e.g., Micallef et al, 2009) continental margins; and the end-member turbidite flows channelled down submarine canyons (e.g., Lykousis et al, 2007). While several large submarine landslides have been imaged offshore using traditional 3D seismic methods (e.g., Frey-Martinez et al, 2005;Gee et al, 2006;Bull et al, 2009), studies of small-to medium-scale structures in fjord or lacustrine settings are limited to interpretation from irregularly distributed cores (e.g., Guyard et al, 2007), sparse twodimensional (2D) seismic lines (50-100 m line spacing) (e.g., Schnellmann et al, 2002), and/or their surface expression in swath/ side-scan sonar imagery (e.g., Canals et al, 2004;Ilstad et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

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3D seismic imaging of buried Younger Dryas mass movement flows: Lake Windermere, UK

et al. 2010

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confidence: 54%

Section: Sss Ivamentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

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3D seismic imaging of buried Younger Dryas mass movement flows: Lake Windermere, UK

et al. 2010

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“…For mild submarine slopes satisfying equations (3.5), with the sliding layer subjected to undrained constant volume deformation, average linear strains parallel to the slope (figure 6) can be approximated as 14) so that the tangential displacements in the sliding layer are given by…”

Section: Z = F(x)mentioning

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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“…They have a wide range of sizes, from meters to hundreds of meters, but this tends to decrease with larger travel distances [Bull et al, 2009;Canals et al, 2004;Davison, 2004;Gee et al, 2006].…”

Section: Introductionmentioning

confidence: 99%

Distribution and characterization of failed (mega)blocks along salt ridges, southeast Brazil: Implications for vertical fluid flow on continental margins

2011

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[1] Three-dimensional seismic data are used to assess the control of halokinetic structures on the distribution of blocks in a mass transport deposit in the Espírito Santo Basin, southeast Brazil. In contrast to what is commonly observed over growing salt structures, the thickness of the MTD-A1 is larger on top of a northwest trending salt ridge. Emphasis was given to the statistical analysis of 172 remnant and rafted blocks identified within Eocene mass transport deposits (MTD-A1). Three styles of block deformation are identified and scale relationships between the geometry of blocks and their relative position on the salt ridge are presented. Average block height reaches 130 m. Average block area reaches 0.43 km 2 , while 11.3% of the total area (A) investigated is covered by blocks (5% < A < 17%). On the basis of variations in block geometry (height, area, width/length ratio, orientation) and their relative distribution, we interpret that most failed strata have been remobilized by adjacent topography created during growth of the investigated salt ridge. We show that the origin of the blocks is linked to densely spaced sets of halokinetic-related faults that deformed the prefailure strata. The presence of underlying faults and blocks of remnant and rafted strata potentially induces sharp variations in the internal permeability of MTD-A1. Thus, the interpreted data shows that megablocks in MTDs can constitute viable fluid pathways on otherwise low-permeability units. This character can significantly decrease seal competence above and on the flanks of halokinetic structures.Citation: Gamboa, D., T. Alves, and J. Cartwright (2011), Distribution and characterization of failed (mega)blocks along salt ridges, southeast Brazil: Implications for vertical fluid flow on continental margins,

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Triggering and Evolution of a Giant Submarine Landslide, Offshore Angola, Revealed by 3D Seismic Stratigraphy and Geomorphology

Cited by 113 publications

References 26 publications

3D seismic imaging of buried Younger Dryas mass movement flows: Lake Windermere, UK

3D seismic imaging of buried Younger Dryas mass movement flows: Lake Windermere, UK

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

Distribution and characterization of failed (mega)blocks along salt ridges, southeast Brazil: Implications for vertical fluid flow on continental margins

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