Contourites and Geohazards
Leader: P. Rebesco
Continental margins are locally unstable and so prone to sudden and catastrophic collapse. This constitutes a significant geohazard for subsea pipelines, cables and other seafloor installations. Sudden slope collapse can also result in major tsunami events. These downslope movements have been the focus of considerable research in recent years, including two current IGCP projects (511 and 585) and one IODP proposal (715 Medslides). Furthermore, slope instabilities have been specifically identified in areas of contourite deposits on continental margins and in ocean gateways, including some of the largest submarine slides known. This objective has strong links to the IGCP Topic on Geohazards and important overlaps with other IGCP projects.
Specific topics for initial focus include:
- Documenting the link between contourite depositional systems, bottom current activity and slope stability/instability on continental margins.
- Exploring the occurrence of weak layers within contourite deposits that may lead to sediment failure, and the controls on their formation during sedimentation and burial.
- Further exploring the potential influence on slope stability of contourite drift location, geometry, sedimentation rate, grain-size distribution and physical properties.
- Evaluating the effects of strong bottom currents on scraping, erosion and undercutting of submarine cables and other subsea installations.
- Maintaining specific links to the current IGCP-585 and possible future IODP 715.
