Slope Instability of Glaciated Continental Margins: Constraints from Permeability-Compressibility Tests and Hydrogeological Modeling Off Storfjorden, NW Barents Sea

Abstract

Climate variations control sediment supply to the continental slope 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 faults. We test this hypothesis using a combination of geophysical and geotechnical data from the Storfjorden Trough Mouth Fan, off southern Svalbard. The results of compressibility and permeability testing are used together with margin stratigraphic models obtained from seismic reflection data, as input for numerical finite elements models to understand focusing of interstitial fluids in glaciated continental margins and influence on timing and location of submarine slope failure. Available results indicate values of overpressure of 0.23–0.5 (slope-shelf) that persist to present-day. This overpressure started to develop in response to onset of Pleistocene glaciations and reduced by half the factor of safety of the continental slope