HR: 0800h
AN: OS31B-0407    [Abstracts]
TI: The Role of High Sedimentation Rates on the Development of Pore Pressure and the Consequences for Slope Stability
AU: * Forsberg, C
EM: cff@ngi.no
AF: Norwegian Geotechnical Institute, P.O.Box 3930 Ullevaal Stadion, Oslo, NO-0806, Norway
AU: Kvalstad, T
EM: tk@ngi.no
AF: Norwegian Geotechnical Institute, P.O.Box 3930 Ullevaal Stadion, Oslo, NO-0806, Norway
AB: Mass transport deposits (MTD) and slides are common features of the Earth's continental slopes. The MTDs are often associated with deposition during sea level low stands, especially during the regressive phase of the sea level cycle. These are periods when sediment transport across the shelf to the slope is at a maximum. We will here present the results of numerical models that use geotechnical sediment properties and sedimentation history to predict pore pressure profiles from both areas with recent rapid deposition and areas where rapid deposition occurred during the low sea level stand associated with the last glacial period. We will use these results to show how the sedimentation history can influence the strength of the sediments and consequently the region's slope stability. The models show that deeply buried sediments are influenced by the long term average sedimentation rate, whereas the shallow deposits reflect recent depositional history. Whereas the latter may influence stability of local slopes, the former provides pore pressure gradients that can set up fluid flow on a more regional scale. Such fluid flow in the deeper parts of the Storegga region is thought to have triggered the Storegga Slide. The pressurization can also lead to hole collapse and shallow water flow during drilling operations.
DE: 3002 Continental shelf and slope processes (4219)
DE: 3022 Marine sediments: processes and transport
DE: 3045 Seafloor morphology, geology, and geophysics
DE: 3070 Submarine landslides
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting