Lessons learned from the monitoring of turbidity currents and guidance for future platform designs

Abstract Turbidity currents transport globally significant volumes of sediment and organic carbon into the deep-sea and pose a hazard to critical infrastructure. Despite advances in technology, their powerful nature often damages expensive instruments placed in their path. These challenges mean that turbidity currents have only been measured in a few locations worldwide, in relatively shallow water depths (<<2 km). Here, we share lessons from recent field deployments about how to design the platforms on which instruments are deployed. First, we show how monitoring platforms have been affected by turbidity currents including instability, displacement, tumbling and damage. Second, we relate these issues to specifics of the platform design, such as exposure of large surface area instruments within a flow and inadequate anchoring or seafloor support. Third, we provide recommended modifications to improve design by simplifying mooring configurations, minimizing surface area and enhancing seafloor stability. Finally, we highlight novel multi-point moorings that avoid interaction between the instruments and the flow, and flow-resilient seafloor platforms with innovative engineering design features, such as feet and ballast that can be ejected. Our experience will provide guidance for future deployments, so that more detailed insights can be provided into turbidity current behaviour, in a wider range of settings.