Novel Acoustic Methods for Directly Monitoring Seabed Sediment Transport, Geohazards & Scour

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This project will develop and field test novel acoustic methods for directly monitoring and understanding processes of seafloor sediment transport and scour, including around Offshore Wind Farms. These seabed processes can be a significant geohazard to offshore wind installations and their seabed power cables, telecommunication cables, oil and gas pipelines and other strategic seafloor infrastructure. The PhD will be based initially around a series of calibrated flume experiments to understand what determines the nature of acoustic signals emitted by seabed sediment transport or erosion processes. For example, it will determine how the power spectrum of radiated sound is affected by flow speed, bedload transport rates and intensity of grain collisions, grain sizes present (sand or mid), and presence and nature of dense near bed layers (e.g. layers of saltating grains or sheet-flow). These laboratory experiment (supervised by Simmons in Hull) will help to interpret acoustic field data to better monitor and understand seabed sediment transport. Hydrophone and/or ADCP data will then be used to monitor processes of sediment transport and seabed scour near Offshore Wind Facilities in the N. Sea. This work will use hydrophone data sets that are already acquired by Neasham in Newcastle. The PhD will finally analyse a series of major field data sets involving hydrophone records of active sediment transport processes. They will include major new field data sets offshore West Africa, California and British Columbia. This work will show how hydrophones can be used to understand hazardous seabed flows, and processes of sediment transport and seabed scour, which may underpin future global seabed listening networks. The aim here is to further test acoustic methods needed to quantify sediment transport around Offshore Wind Facilities, and make use of existing opportunities provided by two NERC funded projects worth over £3.2 Million. This scale of funding is simply not available through the CDT itself (where budgets for single projects are less than £20k at most). This project will also allow the student to take part in two major oceanographic cruises, which will use a wide range of seabed surveying and monitoring tool, thus providing outstanding field training. They are an outstanding training opportunity. It will also include training via analysis of hydrophone data from locations near Offshore Wind Farms in the North Sea.