||Garziglia Sebastien1, Sultan Nabil1, Cattaneo Antonio1, Ker Stephan1, Marsset Bruno1, Riboulot Vincent1, Voisset Michel1, Adamy J.2, Unterseh 2
||1 : IFREMER, F-29280 Plouzane, France.
2 : Total, France
||4th International Symposium on Submarine Mass Movements and Their Consequences, Austin, TX, NOV 07-12, 2009
||Advances in Natural and Technological Hazards Research (1878-9897) (Springer), 2010 , Vol. 28 , P. 55-65
|WOS© Times Cited
||In : Submarine Mass Movements and Their Consequences. ISBN 978-90-481-3070-2
||Cone penetration tests, shear zone, 3D seismic data, ultrahigh-resolution 2D seismic, mass-transport complex, slope stability
||In a site investigation of the eastern part of the offshore Niger delta, cone penetration tests (CPTU) showed significant drops in tip resistance, associated with decreases in sleeve friction and induced excess pore pressures at the interface between superficial sediments and the underlying deposits of a mass-transport complex (MTC) called NG1. Such signature characteristics of weakened zones are clearly expressed at three sites where the drop in tip resistance reaches more than 40% over 2-3 m-thick intervals. Correlations between CPTU profiles and both 3D and ultrahigh-resolution 2D seismic data suggest that the weakened zones surround syndepositional the within the frontal part of NG1. Hence, weakening appears associated with the remobilization of thrust faults, inducing localized plastic shear. Relatively recent, deep-seated structural movements affecting NG1 are suspected to have remobilized these thrusts faults. When considering the sole influence of gravity, the fact that shear strength is mobilized within scattered, limited zones along steeply dipping syndepositional faults is not favorable for the further development of a continuous slope-parallel failure surface above NC1.
||Access on demand
|Author's final draft