Preconditioning and triggering of offshore slope failures and turbidity currents revealed by most detailed monitoring yet at a fjord-head delta

Clare, M.A.; Hughes Clarke, J.E.; Talling, P.T.; Cartigny, M.J.B.; Pratomo, D.G.

doi:10.1016/j.epsl.2016.06.021

Preconditioning and triggering of offshore slope failures and turbidity currents revealed by most detailed monitoring yet at a fjord-head delta

Clare, M.A.; Hughes Clarke, J.E.; Talling, P.T.; Cartigny, M.J.B.; Pratomo, D.G.

Authors

M.A. Clare

J.E. Hughes Clarke

Professor Peter Talling peter.j.talling@durham.ac.uk
Professor

Dr Matthieu Cartigny matthieu.j.cartigny@durham.ac.uk
Associate Professor

D.G. Pratomo

Abstract

Rivers and turbidity currents are the two most important sediment transport processes by volume on Earth. Various hypotheses have been proposed for triggering of turbidity currents offshore from river mouths, including direct plunging of river discharge, delta mouth bar flushing or slope failure caused by low tides and gas expansion, earthquakes and rapid sedimentation. During 2011, 106 turbidity currents were monitored at Squamish Delta, British Columbia. This enables statistical analysis of timing, frequency and triggers. The largest peaks in river discharge did not create hyperpycnal flows. Instead, delayed delta-lip failures occurred 8–11 h after flood peaks, due to cumulative delta top sedimentation and tidally-induced pore pressure changes. Elevated river discharge is thus a significant control on the timing and rate of turbidity currents but not directly due to plunging river water. Elevated river discharge and focusing of river discharge at low tides cause increased sediment transport across the delta-lip, which is the most significant of all controls on flow timing in this setting.

Citation

Clare, M., Hughes Clarke, J., Talling, P., Cartigny, M., & Pratomo, D. (2016). Preconditioning and triggering of offshore slope failures and turbidity currents revealed by most detailed monitoring yet at a fjord-head delta. Earth and Planetary Science Letters, 450, 208-220. https://doi.org/10.1016/j.epsl.2016.06.021

Journal Article Type	Article
Acceptance Date	Jun 15, 2016
Online Publication Date	Jul 5, 2016
Publication Date	Sep 15, 2016
Deposit Date	Oct 24, 2016
Publicly Available Date	Dec 14, 2016
Journal	Earth and Planetary Science Letters
Print ISSN	0012-821X
Publisher	Elsevier
Peer Reviewed	Peer Reviewed
Volume	450
Pages	208-220
DOI	https://doi.org/10.1016/j.epsl.2016.06.021
Related Public URLs	http://nora.nerc.ac.uk/id/eprint/513855/

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Copyright Statement
© 2016 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/).