Which Triggers Produce the Most Erosive, Frequent, and Longest Runout Turbidity Currents on Deltas?

TitleWhich Triggers Produce the Most Erosive, Frequent, and Longest Runout Turbidity Currents on Deltas?
Publication TypeJournal Article
Year2018
AuthorsHizzett, JL, Clarke, JEHughes, Sumner, EJ, Cartigny, MJB, Talling, PJ, Clare, MA
JournalGeophysical Research Letters
Volume45,2
Pages855-863
Date PublishedFebruary 19
PublisherAmerican Geophysical Union
Keywordsriver deltas, settling river plume, submarine landslides, turbidity current runout, turbidity current trigger frequency, turbidity current triggers

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.

Publication Linkhttps://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017GL075751
DOI10.1002/2017GL075751
Refereed DesignationRefereed
Check When Not CCOM Publication