A Weak Layer Feature on the Northern Storegga Slide Escarpment

Abstract

The northern Storegga Slide esearpment and the area affected by the slide has been an area of extensive geological and geotechnical studies during recent years, mainly focusing on sediment transport processes and slope failure mechanisms. The well-preserved stratigraphy established north of the Storegga Slide, also partly exposed along the northern escarpment, is considered to be the closest parallel to the geological setting of the Storegga Slide prior to the slope failure (Fig. 1, 2). The stratigraphic setting is characterised by units consisting dominantly of diamicton and/or ice-proximal upper margin deposits, and hemipelagic and/or glaciomarine seismically well-layered deposits on mid and lower margin settings (Fig. 2). The boundary of these units is regional and usually characterised by a strong seismic reflector. Occasionally, the internal layering of these units also displays a pronounced seismic character, but they have a less distinctive regional appearance.Fig.1.Outline of the Storegga Slide area on the mid-Norwegian margin, with the TOBI sidescan survey area at the northern Storegga Slide escarpment. The location of the airgun seismic profiles presented in Fig. 2 is shown