Successful field work in Finneidfjord and off Vesterålen

Within the framework of the SEABED-funding CDog (Coastal and Deepwater offshore geohazards), two highly successful surveys onboard G.O. Sars (Univ. Bergen) and R/V Seisma (NGU) were completed in the Summer of 2010, the first year of this research project.

The survey work was a critical part of the project, which aims at understanding the occurrence of smaller-scale landslides in different geological and environmental settings, through sampling and geophysical site surveying.

The data acquired in 2010 include high-quality continuous Calypso cores down to ~15m; free-fall penetrometer data (with pore pressure and dissipation tests), swath bathymetry, VHR-3D chirp seismic, VHR-2D Topas seismic, ocean-bottom seismometer data, etc.

Data are currently being processed and analyzed at the different institutes involved. Geological analysis focuses on stratigraphy, lithology and chronology (XRF, X-ray, dating, grain size distribution, MSCL, etc.). A dedicated geotechnical program was established on the different facies observed on the X-rays, in particular on the depth interval in which the suspected slip plane occurs. Geotechnical tests include undrained shear strength (undisturbed, remoulded), in addition to common index testing (water content, plasticity limits, etc.).

Partners: ICG-6 (NGI, NGU, NORSAR), Univ. Bergen, National Oceanography Centre Southampton, MARUM University of Bremen.


Figure: Survey map of data acquired during the summer of 2010 in Finneidfjord. The seismic profile (not fully processed) is acquired with the VHR-3D chirp system of NOCS, showing well-stratified sequences as well as the landslide body, with unprecedented resolution.