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How Do ∼2° Slopes Fail in Areas of Slow Sedimentation? A Sensitivity Study on the Influence of Accumulation Rate and Permeability on Submarine Slope Stability

  • Morelia UrlaubEmail author
  • Antonis Zervos
  • Peter J. Talling
  • Doug G. Masson
  • Chris I. Clayton
Conference paper
Part of the Advances in Natural and Technological Hazards Research book series (NTHR, volume 31)

Abstract

Overpressure generation due to rapid sediment deposition can result in low effective stresses within the sediment column. It has been proposed that these large overpressures are the main preconditioning factor for causing large-scale submarine slope failure on passive continental margins, such as those in the Gulf of Mexico and offshore Norway. The rate of overpressure generation depends on the sedimentation rate, sediment compressibility and permeability. The Gulf of Mexico and the Norwegian continental slope have experienced comparatively high sediment input, but large-scale slope failure also occurs in locations with very low sedimentation rates such as the Northwest African continental margin. Here we show results from 2D numerical modelling of a 2° continental slope subjected to deposition rates of 0.15 m/ka. These results do not indicate any evidence for significant overpressure or slope instability. We conclude that factors other than overpressure must be fundamental for initiating slope failure, at least in locations with low sedimentation rates.

Keywords

Overpressure Continental margin Submarine landslide Slope ­stability modelling 

Notes

Acknowledgments

Sebastian Krastel kindly provided reflection seismic lines offshore NW Africa. Brandon Dugan, Peter Flemings and Derek Sawyer are thanked for their encouragement to address these problems. We also thank the reviewers C. Berndt and A. Kopf for their constructive reviews.

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Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Morelia Urlaub
    • 1
    Email author
  • Antonis Zervos
    • 2
  • Peter J. Talling
    • 1
  • Doug G. Masson
    • 1
  • Chris I. Clayton
    • 2
  1. 1.National Oceanography CentreSouthamptonUK
  2. 2.School of Civil Engineering and the EnvironmentUniversity of SouthamptonSouthamptonUK

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