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Subaerial rivers and turbidity currents are the two most voluminous sediment transport processes on our planet, and it is important to understand how they are linked offshore from river mouths. Previously, it was thought that slope failures or direct plunging of river floodwater (hyperpycnal flow) dominated the triggering of turbidity currents on delta fronts. Here we reanalyze the most detailed time‐lapse monitoring yet of a submerged delta; comprising 93 surveys of the Squamish Delta in British Columbia, Canada. We show that most turbidity currents are triggered by settling of sediment from dilute surface river plumes, rather than landslides or hyperpycnal flows. Turbidity currents triggered by settling plumes occur frequently, run out as far as landslide‐triggered events, and cause the greatest changes to delta and lobe morphology. For the first time, we show that settling from surface plumes can dominate the triggering of hazardous submarine flows and offshore sediment fluxes.
Center for Coastal and Ocean Mapping
Journal or Conference Title
Geophysical Research Letters
Digital Object Identifier (DOI)
Hizzett, J.L., Hughes Clarke, J.E., Sumner, E.J,, Cartigny, M.J.B., Talling, P.J., Clare, M.A., 2017, Which Triggers Produce the Most Erosive, Frequent, and Longest Runout Turbidity Currents on Deltas?: Geophysical Research Letters, 45, 855–863, https://doi.org/10.1002/2017GL075751
This is an article published by Wiley in Geophysical Research Letters in 2017, available online: https://dx.doi.org/10.1002/2017GL075751