Submarine slope failures due to pipe structure formation

• Published in: Nature communications Vol. 9; no. 1; pp. 715 - 6
• Main Authors: Elger, Judith, Berndt, Christian, Rüpke, Lars, Krastel, Sebastian, Gross, Felix, Geissler, Wolfram H.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19.02.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 704/2151/213/4116; 704/2151/2809; 704/4111; Bottom water; Computational fluid dynamics; Environmental changes; Failure; Gas hydrates; Humanities and Social Sciences; Hydrates; Landslides; Landslides & mudslides; Mathematical models; multidisciplinary; Ocean models; Overpressure; Permeability; Pipes; Polar environments; Science; Science (multidisciplinary); Sea level; Seismic stability; Seismic surveys; Slope stability; Water depth
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-03176-1

There is a strong spatial correlation between submarine slope failures and the occurrence of gas hydrates. This has been attributed to the dynamic nature of gas hydrate systems and the potential reduction of slope stability due to bottom water warming or sea level drop. However, 30 years of research into this process found no solid supporting evidence. Here we present new reflection seismic data from the Arctic Ocean and numerical modelling results supporting a different link between hydrates and slope stability. Hydrates reduce sediment permeability and cause build-up of overpressure at the base of the gas hydrate stability zone. Resulting hydro-fracturing forms pipe structures as pathways for overpressured fluids to migrate upward. Where these pipe structures reach shallow permeable beds, this overpressure transfers laterally and destabilises the slope. This process reconciles the spatial correlation of submarine landslides and gas hydrate, and it is independent of environmental change and water depth. There is a strong correlation between submarine slope failures and the occurrence of gas hydrates. Here, the authors use a combination of seismic data and numerical modelling to show that overpressure at the gas hydrate stability zone leads to potential destabilization of the slope and submarine landslides.