Constraining geohazards to the past: Impact assessment of submarine mass movements on seabed development

This paper presents a conceptual review of submarine mass movements and associated hazards such as run-out and turbidity currents, and their implications for the planning of exploration and development activities. Submarine mass movements are placed in the context of ground models and geohazard scenarios from which conditioning factors and trigger mechanisms can be assessed and event magnitudes estimated. The approach to dating these events in order to derive a frequency is discussed with reference to radiometric, biostratigraphic and Optically Stimulated Luminescence techniques that have been successfully deployed in recent projects. The need for good stratigraphic control, both seismostratigraphic and lithological, is emphasized. Based on the ground model and geohazard scenarios, ground movement at different locations within the mass movement system can be inferred. This understanding along with predicted soil conditions derived from the ground model and evolutionary history of the site allows the potential consequences on well conductors, facilities and flowlines to be assessed and the need for geohazard design and mitigation evaluated. These findings indicate the constraints on possible exploration and development activities.