Geomorphology and Remote Physical Properties of Late Quaternary Slide Structures using Decimetre-Resolution 3D Seismic Volumes: Insights for Deep Water Geohazard Assessment

Abstract

Traditional exploration methods, involving a combination of two-dimensional seismic profiles with cores and/or swath bathymetry/side-scan sonar, do not adequately sample all three spatial dimensions for true morphological mapping of submarine mass movement deposits. It is only with the acquisition of three-dimensional (3D) seismic volumes that the complex 3D nature of these features can be correctly imaged. Over the last 5-10 years, the interpretation of industry-scale 3D seismic volumes from numerous continental shelf locations has allowed effective mapping of the deposit morphology. Features such as head scarps, side walls, extensional/compressional ridges, striations on the basal surface, translated blocks, and preservation/deformation of internal reflectors have been shown to constrain the direction and method of material transport. Here we demonstrate the application of these techniques to the shallow-water environment using decimeter-resolution 3D seismic volumes, with case studies from Trondheimsfjorden (Norway) and Lake Windermere (UK Lake District). Through the mapping of top/base reflector morphologies, internal structure, translated blocks, and head scarps/side walls we demonstrate the same techniques can be used to differentiate flow mechanics (coherent slide blocks, slumped material, debris flows, and a mass flow) and quantify direction of motion at this radically different scale.