Seafloor instability in the Gulf of Lion
Shray Badhani | Ifremer Brest
In order to refine the geohazard assessment in the central Mediterranean area, two research cruises (PRISME2 and PRISME3) took place in 2013 to obtain data about submarine landslides in the Gulf of Lion. In particular, two large Mass Transport Deposits (MTDs, the Western and Eastern MTD) were recognized in the Rhône deep-sea turbiditic system, on the western and eastern flanks of the Rhône submarine valley. These deposits were described in the literature, but never analyzed in details by integrating high resolution multichannel seismic data (also with deep-towed vehicle SYSIF), sediment sampling for stratigraphic and geotechnical characterization and in situ measurement.
The aims of this project are:
- to identify the morphological and sedimentological characters of submarine landslides in the Gulf of Lions;
- to establish a chronological framework for failed sedimentary units and adjacent turbidite deposits;
- to identify major trigger mechanisms and the possible presence of weak layers.
The analytical work will include a quantitative morphological analysis of the seafloor, the integration of geophysical data with in situ penetrometer measurements (12 CPTU and 2 P-wave velocity) and the analysis of 12 sediment cores (1 to 22 m long). The results of high-resolution analysis and correlation of failed units, encasing undeformed sedimentary successions and adjacent sediment bodies will be used in numerical model to evaluate seafloor stability.