We propose to use these 'pump priming' funds to initiate an ambitious new industry consortium and UK centre of excellence for research into marine geohazards. Funding is sought specifically to: 1) set up an experimental laboratory with a set of novel sensors for imaging dense sediment flows, and 2) develop initial links with key industry stakeholders (e.g. FUGRO GeoConsulting Ltd). NOC has a strong submarine geohazards group whose work is based mainly on field observations; for instance it is leading a £2.3M NERC Consortium of tsunami-landslide hazards. It has just been awarded a £850k NERC grant to monitor active submarine flows in Monterey Canyon offshore California. Here we seek funding to develop a new experimental laboratory to test hypotheses posed by field observations. Full-scale flow observations in the field have recently confirmed an earlier hypothesis, which suggest that dense near-bed layers with high sediment concentrations often form a key part of turbidity currents. These dense layers are the most poorly understood and hence contentious part of turbidity currents, because most techniques can only image within the dilute top part of the flows. Dense near-bed layers are, however, important for geohazard analysis because their high density and basal position can exert large forces on infrastructure located close to the bed. The lateral loads they impose may result in displacement of pipelines, or in severe cases result in full bore rupture. The consequences may include economic loss, environmental effects and reputational damage to the operator. We now need to understand how these dense near-bed layers form and evolve, and what their impact is to exerted pressures and forces. Although previous experiments have successfully measured velocities within dense near-bed layers, sediment concentration measurements have so far not been possible within these layers due to their high sediment content. Here we seek funds to apply a new method of sediment concentration measurements based on Electrical Resistivity Tomography (ERT). ERT techniques are able to measures sediment concentration contrasts to characterise sedimentary reservoirs in the subsurface. This technique is not limited by sediment concentration and preliminary numerical simulations have shown that this technique can resolve sediment concentration profiles in dense near-bed layers of turbidity currents. We will use the novel ERT, in combination with velocity measurements to measure for a first time a combined velocity and sediment concentration profile through dense near-bed layers. Such simultaneous measurements will help to understand: i) what the maximum thickness of these dense layers can be, ii) how much sediment they are able to transport into the ocean, and iii) how large the impact of these layers can be on submarine pipelines. The second aim of this proposal is to develop links with FUGRO GeoConsulting Ltd. FUGRO performs risk assessments on marine geohazards for numerous oil and gas companies. As part of this assessment, numerical modelling provides a quantitative expression of likely impact and consequence to the integrity of seafloor structures. Flow densities and velocities of near-bed layers form vital inputs in these models. Currently inferred densities and velocities are required as model input, which are not well calibrated, and gross assumptions must be made. Therefore, this experimental work will provide useful direct input to improve the current model assumptions. The West Nile Delta will be used as a case study to show the direct impact of the experiments on real-world risk assessment calculations. The grant will also be used to transfer people and knowledge between FUGRO and NOC. This transfer will take place during a series of 3 meeting both at NOC and at FUGRO. Additionally two FUGRO consultants will spend 3 weeks at NOC to ensure a smooth transfer of knowledge from the experiments into the industry risk assessments.

Our over-arching aim is to better understand the impact of powerful submarine flows, called turbidity currents, on pipelines and other seabed infrastructure used to recover oil and gas. Turbidity currents pose a serious hazard to expensive seabed installations, especially in deeper-water settings. These sediment flows are particularly hazardous because they can be exceptionally powerful (travelling at speeds of up to 20 m/s), and can flow for long distances (100s km), causing damage over vast areas of seafloor. Even weaker flows travelling at ~1-2 m/s can severely damage seafloor equipment, or break strategically important submarine telecommunication cables, while some flows have maintained speeds in excess of 5 m/s for hundreds of kilometres. This makes hazard mitigation by local re-routing of pipelines difficult. Where seafloor topography is rugged, many operators route pipelines within canyons; however, these are focal points for turbidity current activity. Mitigating against turbidity current geohazards, particularly within canyons, can have very significant cost implications for industry - additional deepwater pipeline routing costs ~ $3 million per km. Mitigation costs of $2 billion are predicted to route pipelines under the Congo Canyon, where turbidity current hazard is deemed to be high. Perhaps just as importantly, pipeline oil spills could lead to major reputational damage. Given concern over accidents to structures used to recover oil and gas, a focus on geohazards is also aligned with NERC's environmental responsibility. The most remarkable aspect of turbidity currents is how few direct measurements there are from flows, in part because they damage monitoring equipment placed on the seafloor. Several lines of evidence point to the existence of a region of high sediment concentration at the base of turbidity currents. These dense basal layers are of key important because of: (i) their location just above the bed where most submarine infrastructure is located; and (ii) they carry most momentum due to their large density. Yet, sediment concentration has never been measured directly measured in these layers. Physical experiments, numerical modeling and ancient deposits provide valuable insights into these flows; but there is a compelling need to monitor full-scale flows in action. This project is timely because it will develop innovative field-based techniques for imaging near bed flow structure and vertical changes in sediment concentration in situ. Aims: (1) Our first aim is to develop and field test a novel technique for remote sensing of dense near bed layers. (2) Our second aim is to better understand the nature of near bed dense layers. (3) Our third aim is to embed improved understanding of dense near-bed layers into numerical models used by industry to assess impact of turbidity currents on oil and gas pipelines. (4) The project will also help to establish an international centre of excellence for submarine geohazard research at the UK National Oceanography Centre. Here we propose to make direct measurements of dense basal layers that form part of the turbidity currents occuring daily during the elevated summer river discharge on the Squamish Delta, located in Howe Sound, Canada. We will use an innovative four-point mooring to hold a vessel and suspended instrumentation payload stable above an active channel system, while we observe the dense basal layer with a Chirp sub-bottom profiler. The low frequency and broad bandwidth (1.5 -13.0 kHz) Chirp source guarantees penetration through dense near-bed layers, resolving layers with ~10 cm resolution. These field observations will help to understand the fundamental character of near bed layers, and the situations in which they form.

Carbonate soils cover over 40% of the world's seabed, where offshore structures, pipelines, artificial islands and other marine structures are founded. For the most part, carbonate soils are of biogenic origin comprising skeleton bodies and shells of small organisms, the shelly carbonate sands. These soils are a complex and poorly understood material as evidenced by a number of accidents reported during platform installation in the 80s. As a consequence, shelly sands have been placed into a niche classification of "problematic soils" in most design guides. While failures are now relatively rare, conservative methods and high factors of safety are commonly used. Understanding the behaviour of shelly carbonate sand is critical for the design of foundations for offshore structures. In particular, understanding the physical phenomena taking place at the microscale has the potential to spur the development of robust computational methods to be integrated into novel or existing design approaches. Image-based geomechanics is a fascinating research field that has the potential to transform the way soils are investigated and modeled. The ability to follow deformation at the microscale has helped to answer fundamental questions about the soil behaviour observed at the macro-scale. The proposed research uses 4D synchrotron x-ray imaging and post analysis to investigate the kinematics and the strain maps of a shelly carbonate sand under compression. The outcomes will contribute scientific understanding on the multiscale behaviour of shelly carbonate sands. This will form the basis to develop fabric-informed constitutive models to better predict the soil response, thus improving design practices for foundations of offshore structures. The ambition of this project is to contribute towards safer, less conservative and more sustainable ground structures and reduce the financial risks associated with unforeseen ground response during construction of offshore foundations. This multiscale methodology and image algorithms here developed, will be valuable to the broad granular media community to simulate mechanical processes in additive manufacturing, mining, food and pharmaceutical industries.

The UK is the world leader in offshore wind energy; almost 40% of global capacity is installed in UK waters. A new ambitious target of 40GW of wind power by 2030 aims to produce sufficient offshore wind capacity to power every home, helping to achieve net zero carbon emissions by 2050. Offshore wind turbine (OWT) foundations, which are typically steel monopiles, contribute approximately 25% to a windfarm's capital cost. The size of OWTs is increasing rapidly and continued optimisation of foundation design is paramount. Recent research has led to significant advances through theoretical developments combined with high-quality field-testing. Despite recent advances, there remains significant uncertainty in the measurement and interpretation of key soil deformation parameters that underpin new and existing design approaches. The central aim of SOURCE is to use rigorous measurement and interpretation in the field and laboratory to quantify and reduce material parameter uncertainty and minimise the impact on the predictive capability of OWT foundation design methods. Improved site characterisation will contribute to increased security in design, lowering capital costs, subsidies and carbon emissions and meeting the UK's ambitious new energy targets.

Submarine landslides can be far larger than terrestrial landslides, and many generate destructive tsunamis. The Storegga Slide offshore Norway covers an area larger than Scotland and contains enough sediment to cover all of Scotland to a depth of 80 m. This huge slide occurred 8,200 years ago and extends for 800 km down slope. It produced a tsunami with a run up >20 m around the Norwegian Sea and 3-8 m on the Scottish mainland. The UK faces few other natural hazards that could cause damage on the scale of a repeat of the Storegga Slide tsunami. The Storegga Slide is not the only huge submarine slide in the Norwegian Sea. Published data suggest that there have been at least six such slides in the last 20,000 years. For instance, the Traenadjupet Slide occurred 4,000 years ago and involved ~900 km3 of sediment. Based on a recurrence interval of 4,000 years (2 events in the last 8,000 years, or 6 events in 20,000 years), there is a 5% probability of a major submarine slide, and possible tsunami, occurring in the next 200 years. Sedimentary deposits in Shetland dated at 1500 and 5500 years, in addition to the 8200 year Storegga deposit, are thought to indicate tsunami impacts and provide evidence that the Arctic tsunami hazard is still poorly understood. Given the potential impact of tsunamis generated by Arctic landslides, we need a rigorous assessment of the hazard they pose to the UK over the next 100-200 years, their potential cost to society, degree to which existing sea defences protect the UK, and how tsunami hazards could be incorporated into multi-hazard flood risk management. This project is timely because rapid climatic change in the Arctic could increase the risk posed by landslide-tsunamis. Crustal rebound associated with future ice melting may produce larger and more frequent earthquakes, such as probably triggered the Storegga Slide 8200 years ago. The Arctic is also predicted to undergo particularly rapid warming in the next few decades that could lead to dissociation of gas hydrates (ice-like compounds of methane and water) in marine sediments, weakening the sediment and potentially increasing the landsliding risk. Our objectives will be achieved through an integrated series of work blocks that examine the frequency of landslides in the Norwegian Sea preserved in the recent geological record, associated tsunami deposits in Shetland, future trends in frequency and size of earthquakes due to ice melting, slope stability and tsunami generation by landslides, tsunami inundation of the UK and potential societal costs. This forms a work flow that starts with observations of past landslides and evolves through modelling of their consequences to predicting and costing the consequences of potential future landslides and associated tsunamis. Particular attention will be paid to societal impacts and mitigation strategies, including examination of the effectiveness of current sea defences. This will be achieved through engagement of stakeholders from the start of the project, including government agencies that manage UK flood risk, international bodies responsible for tsunami warning systems, and the re-insurance sector. The main deliverables will be: (i) better understanding of frequency of past Arctic landslides and resulting tsunami impact on the UK (ii) improved models for submarine landslides and associated tsunamis that help to understand why certain landslides cause tsunamis, and others don't. (iii) a single modelling strategy that starts with a coupled landslide-tsunami source, tracks propagation of the tsunami across the Norwegian Sea, and ends with inundation of the UK coast. Tsunami sources of various sizes and origins will be tested (iv) a detailed evaluation of the consequences and societal cost to the UK of tsunami flooding , including the effectiveness of existing flood defences (v) an assessment of how climate change may alter landslide frequency and thus tsunami risk to the UK.