Submarine Landslide Dynamics and Impact on Offshore Wind Infrastructure

Project Description:

The Project

The over-arching aim of the project is to explore post-failure mobility of submarine landslides and quantify their impact on offshore wind infrastructure. By multiphase and multiscale modelling of subaqueous landslides with analytical, and numerical approaches, this research helps decision makers manage safe offshore renewable developments.

Submarine landslides are among the most challenging of natural hazards due to difficulties in quantifying consequential debris flow runout and adverse consequences. Submarine landslides can be very long (10 ~ 100km), e.g., the Miller Slide along the Atlantic continental margin of the UK, and can occur on rather mild continental slopes (1° ~ 5°). Submarine landslides are even more common in some emerging OSW markets such as the Mediterranean Sea, the Gulf of Mexico, SE Asia, and the NW Africa.

Rapid OSW energy development in these landslide prone areas make relevant subsea infrastructure, such as fixed foundations and transmission cables, at risk from potential landslides. Remote renewable energy generation will play an increasing role into the future, which requires subsea infrastructure to be installed or cross continental slopes and hence increases risks from landslide geohazard. As well as threats to offshore energy and communication infrastructure, tsunami generation (see an existing Aura project) extends the risks to coastal communities.

After failure initiation, materials evolve from intact solid soils to fluid-like debris flow and even turbidity currents (see another Aura project). The dynamics of motion become of interest once the sliding mass moves downslope, controlling the run-out distance, and potential impact on offshore wind infrastructure. Attention has previously been paid to predicting run-out features like distance using experimental, numerical and theoretical approaches. However, landslide dynamics with different initial conditions and water entrainment, and the direct impacts to OSW facilities, remain to be understood more clearly.

The specific aims of the project are as follows:

• Aim 1: study dynamic motions of submarine landslide and quantify likely ranges of runout distances, maximum velocities and maximum volumes for different initial landslide conditions.
• Aim 2: quantify slide mass impact on OSW infrastructure (mainly fixed OSW foundations and cables) and assess integrity of the infrastructure interacted with different landslide phases.

References:

• Power, P.T., Clare, M., Rushton, D., Rattley, M. (2011). Reducing Geo-risks for Offshore Developments. ISGSR 2011 – Geotechnical Safety and Risk.
• Bakhsh, T.T., Simpson, K., Lapierre, T. etal. (2021). Potential geo-hazard to floating offshore wind farms in the US pacific. IOWTC2021.
• Hizzett, J.L., Hughes Clarke, J.E., Sumner, E.J., etal. (2018). Which triggers produce the most erosive, frequent and longest runout turbidity currents on deltas? GRL, 45 (2): 855-863.
• Coombs, W.M., Augarde, C.E. (2020). AMPLE: A Material Point Learning Environment. Adv. Eng. Soft., 139: 102748.
• Zhang, W. and Randolph, M.F. (2020). A smoothed particle hydrodynamics modelling of soil–water mixing and resulting changes in average strength. IJNAG.