Preconditioning and triggering of offshore slope failures and turbidity currents revealed by most detailed monitoring yet at a fjord-head delta
Preconditioning and triggering of offshore slope failures and turbidity currents revealed by most detailed monitoring yet at a fjord-head delta
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.
river delta, submarine landslides, turbidity current, geohazard, mass failure, sediment flow
208-220
Clare, M.A.
2b5fe9d9-a4fa-4c54-b7ed-337d15b1c4cf
Hughes Clarke, J.E.
81b97b31-58a8-474e-b693-c4f20a54d992
Talling, P.J.
1cbac5ec-a9f8-4868-94fe-6203f30b47cf
Cartigny, M.J.
d252d7b1-16c6-47b1-bf86-8087070934ce
Pratomo, D.G.
10192727-8ce6-4a9a-9d2f-4d593206ee18
15 September 2016
Clare, M.A.
2b5fe9d9-a4fa-4c54-b7ed-337d15b1c4cf
Hughes Clarke, J.E.
81b97b31-58a8-474e-b693-c4f20a54d992
Talling, P.J.
1cbac5ec-a9f8-4868-94fe-6203f30b47cf
Cartigny, M.J.
d252d7b1-16c6-47b1-bf86-8087070934ce
Pratomo, D.G.
10192727-8ce6-4a9a-9d2f-4d593206ee18
Clare, M.A., Hughes Clarke, J.E., Talling, P.J., Cartigny, M.J. and Pratomo, D.G.
(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, .
(doi:10.1016/j.epsl.2016.06.021).
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.
Text
FINAL SQUAMISH EPSL.pdf
- Accepted Manuscript
Text
1-s2.0-S0012821X16303089-main.pdf
- Version of Record
More information
Accepted/In Press date: June 2016
Published date: 15 September 2016
Keywords:
river delta, submarine landslides, turbidity current, geohazard, mass failure, sediment flow
Organisations:
Marine Geoscience
Identifiers
Local EPrints ID: 397166
URI: http://eprints.soton.ac.uk/id/eprint/397166
ISSN: 0012-821X
PURE UUID: 4f746a26-0eb8-4d57-b5b9-96f4949c22fd
Catalogue record
Date deposited: 21 Jun 2016 14:06
Last modified: 15 Mar 2024 05:41
Export record
Altmetrics
Contributors
Author:
M.A. Clare
Author:
J.E. Hughes Clarke
Author:
P.J. Talling
Author:
M.J. Cartigny
Author:
D.G. Pratomo
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics