Quantifying the role of sandy–silty sediments in generating slope failures during earthquakes: example from the Algerian margin

Autor: Nabil Sultan, Gabriela Dan, K. Yelles, Jacques Déverchère, Bruno Savoye
Přispěvatelé: Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université européenne de Bretagne - European University of Brittany (UEB), FUGRO FRANCE, FUGRO, Centre de Recherche en Astronomie Astrophysique et Géophysique (CRAAG)
Rok vydání: 2008
Předmět:
Zdroj: International Journal of Earth Sciences
International Journal of Earth Sciences, Springer Verlag, 2009, 98 (4), pp.769-789. ⟨10.1007/s00531-008-0373-5⟩
International Journal of Earth Sciences (1437-3254) (Springer), 2009-06, Vol. 98, N. 4, P. 769-789
ISSN: 1437-3262
1437-3254
DOI: 10.1007/s00531-008-0373-5
Popis: The Algerian margin is a seismically active region, where during the last century, several large magnitude earthquakes took place. This study combines geotechnical and sedimentological data with numerical modelling to quantitatively assess the present-day slope stability of the Algerian margin. Geotechnical laboratory tests, such as cyclic triaxial tests, oedometric tests and vane shear tests were carried out on sediment cores collected on the study area. The liquefaction potential of a sediment column located about 30 km from the Boumerdes earthquake epicentre of 21st May 2003 was evaluated theoretically for an earthquake of M w = 6.8. We show that thin sand and silt beds such as those described on recovered sediment cores are the main cause of sediment deformation and liquefaction during earthquakes. Numerical calculations showed that the slope failure may occur during an earthquake characterised by a PGA in excess of 0.1g, and also that, under a PGA of 0.2g liquefaction could be triggered in shallow silty–sandy deposits. Moreover, comparison of the predicted slope failure with failure geometries inferred from seafloor morphology showed that earthquakes and subsequent mass movements could explain the present-day morphology of the study area.
Databáze: OpenAIRE
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