Morphology, distribution and origin of recent submarine landslides of the Ligurian Margin (North-western Mediterranean):
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ORIGINAL RESEARCH PAPER
Morphology, distribution and origin of recent submarine landslides of the Ligurian Margin (North-western Mediterranean): some insights into geohazard assessment Se´bastien Migeon • Antonio Cattaneo • Virginie Hassoun • Christophe Larroque • Nicola Corradi • Francesco Fanucci • Alexandre Dano • Bernard Mercier de Lepinay Franc¸oise Sage • Christian Gorini
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Received: 29 March 2010 / Accepted: 15 March 2011 / Published online: 26 March 2011 Ó Springer Science+Business Media B.V. 2011
Abstract Based on new multibeam bathymetric data, seismic-reflection profiles and side-scan sonar images, a great number of submarine failures of various types and sizes was identified along the northern margin of the Ligurian Basin and characterized with 3 distinct end-members concerning their location on the margin, sedimentary processes and possible triggering mechanisms. They include superficial landslides mainly located in the vicinity of the main mountain-supplied rivers and on the inner walls of canyons (typically smaller that 108 m3 in volume: Type 1), deep scars 100–500 m high along the base of the continental slope (Type 2), and large-scale scars and Mass Transport Deposits (MTDs) affecting the upper part of the slope (Type 3 failures). The MTDs are located in different environmental contexts of the margin, including the deep Var Sedimentary Ridge (VSR) and the upper part of the S. Migeon (&) V. Hassoun A. Dano F. Sage UMR Ge´oAzur, Universite´ de Nice-Sophia Antipolis, CNRS, OCA, Port de la darse, 06235 Villefrance/Mer, France e-mail: [email protected] A. Cattaneo IFREMER, GM-LES, 29280 Plouzane´, France C. Larroque B. Mercier de Lepinay UMR Ge´oAzur, Universite´ de Nice-Sophia Antipolis, CNRS, OCA, 250 Rue A. Einstein, 06560 Valbonne, France N. Corradi University of Genova, Dip.Te.Ris, Corso Europa, 26, 16100 Genoa, Italy F. Fanucci University of Trieste, DiGe, Italy C. Gorini UMR iSTeP, Universite´ Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris cedex05, France
continental slope in the Gulf of Genova (Finale Slide and Portofino Slide), with volumes of missing sediment reaching up to 1.5 9 109 m3. High sedimentation rates related to hyperpycnal flows, faults and earthquake activity, together with sea-level fluctuations are the main factors invoked to explain the distribution and sizes of these different failure types. Keywords Ligurian Sea Submarine landslides Seafloor morphology Seismic-reflection profiles Side-scan sonar
Introduction Submarine failures have been described with increasing details, especially during the last two decades, in a wide range of climatic and tectonic settings, from glacial to subequatorial areas (Huhnerbach and Masson 2004; Imbo et al. 2003; Laberg et al. 2000; McAdoo et al. 2000; Piper et al. 1997) and along both passive and active margins (Collot et al. 2001; Goldfinger et al. 2000; Moore et al. 1989; Urgeles et al. 1997). Triggering factors are, consequently, as diverse as sea-level fluctuations, earthquakes, high-sediment supply leading t
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