Climate variations control sediment supply to the continental margin as well as glacial advances and retreats, which (a) cause significant stress changes in the sedimentary column and redistribution of interstitial fluids, (b) induce a particular margin stratigraphic pattern and permeability architecture and (c) are at the origin of isostatic adjustments that may reactivate seismogenic faults. All of these factors contribute to either reduce the shear strength or increase the shear stresses acting on marine sediments. Therefore, the hypothesis that climate change is a first order control on timing and location of arctic submarine slope failure can be drawn. We aim to test this hypothesis using a combination of geophysical and geotechnical data from the Storfjorden Trough Mouth Fan, off southern Svalbard. Available results already indicate that submarine slope failure is widely present in the area, and is controlled by thickness of deglacial plumites. We are carrying out a laboratory program to test the compressibility and permeability characteristics of glacigenic diamictons and hemipelagic sediments, the main sediment types in the area, and how burial affects these sediment properties that control interstitial fluid flow and pore pressure build-up. The results are used together with margin stratigraphic models obtained from seismic reflection data, as input for numerical models to understand focusing of interstitial fluids in glaciated continental margins and influence on timing and location of submarine slope failure. Available results indicate that significant overpressure (0.7; ratio between pore pressure and overburden stress) that persists to Present-day started to develop in response to onset of Pleistocene glaciations. Margin progradation controlled the location of depocenters resulting in maximum overpressures at the upper continental slope at a depth of between 800-1500 m below seafloor. This depth range is coincident with the detachment level observed in various slope failures in the arctic region, indication that overpressure development could be a major control in arctic submarine slope failure

IPY2012 Conference Montréal. From Knowledge to Action, 22-27 April 2012, Montréal, Canada

Peer Reviewed