Investigation of a possible submarine landslide at the Var delta front (Nice continental slope, southeast France)
|Author(s)||Sultan Nabil1, Savoye Bruno1, Jouet Gwenael1, Leynaud Didier1, Cochonat Pierre1, Henry P.2, Stegmann Sylvia1, Kopf Achim3|
|Affiliation(s)||1 : IFREMER, Dept Marine Geosci, F-29280 Plouzane, France.
2 : CEREGE, F-13545 Aix En Provence, France.
3 : Univ Bremen, Dept Earth Sci, RCOM, D-28359 Bremen, Germany.
|Source||Canadian Geotechnical Journal (0008-3674) (National Research Council Canada), 2010-04 , Vol. 47 , N. 4 , P. 486-496|
|WOS© Times Cited||46|
|Keyword(s)||CPTu, gassy soil, piezocone, shear zone, submarine landslides|
|Abstract||The Var prodelta progrades across a straight, narrow shelf (less than 2 km wide) with a very steep continental slope reaching locally more than 30 degrees. Historically, the Var delta front is sadly famous for the 1979 catastrophic submarine landslide that resulted in several casualties and infrastructural damage. Geotechnical and geophysical investigations carried out in late 2007 to the east of the 1979 landslide scar provide evidence for the possible occurrence of a new important sedimentary collapse and submarine landslide. Geophysical data acquired in the area show the presence of several seafloor morphological steps rooted to shallow subsurface seismic reflections. Moreover, in situ piezocone measurements demonstrate the presence of several shear zones at the border of the shelf break at different depths below the seafloor. The aim of this technical note is to present and discuss acquired geotechnical and geophysical data in terms of failure mechanisms and submarine landslides. Both geophysical and geotechnical data suggest the start-up of a progressive failure mechanism and reveal the possible occurrence of a submarine landslide and the urgent need for mitigation procedures.|