The 1996 Finneidfjord Slide; Seafloor Failure and Slide Dynamics

Abstract

The 1996 Finneidfjord slide was a combined submarine/subaerial, retrogressive flow/ quick clay slide that mobilized 1 mill. m3 of sediments and killed four people. Interpretation of the morphology of the submarine slide scar and the slide deposits combined with eyewitness observations suggest that the initial failure occurred on the steepest slope of the foreshore platform. Detachment along a weak layer within silty clay caused unloading, oversteepening and erosion and triggered retrogressive sliding. Outrunner blocks from the slide occur up to 1.6 km outside the main debris lobe. Excess hydrostatic pressure related to meteorological and anthropogenic influence is thought to have triggered the slide.