Preconditioning by sediment accumulation can produce powerful turbidity currents without major external triggers

Bailey，Lewis P.1,2; Clare，Michael A.1; Rosenberger，Kurt J.3; Cartigny，Matthieu J.B.4; Talling，Peter J.4; Paull，Charles K.5; Gwiazda，Roberto5; Parsons，Daniel R.6; Simmons，Stephen M.6; Xu，Jingping7; Haigh，Ivan D.2; Maier，Katherine L.3,5,8; McGann，Mary9; Lundsten，Eve5

2021-05-15

10.1016/j.epsl.2021.116845

EARTH AND PLANETARY SCIENCE LETTERS   影响因子和分区

0012-821X

Turbidity currents dominate sediment transfer into the deep ocean, and can damage critical seabed infrastructure. It is commonly inferred that powerful turbidity currents are triggered by major external events, such as storms, river floods, or earthquakes. However, basic models for turbidity current triggering remain poorly tested, with few studies accurately recording precise flow timing. Here, we analyse the most detailed series of measurements yet made of powerful (up to 7.2 m s) turbidity currents, within Monterey Canyon, offshore California. During 18-months of instrument deployment, fourteen turbidity currents were directly monitored. No consistent triggering mechanism was observed, though flows did cluster around enhanced seasonal sediment supply. We compare turbidity current timing at Monterey Canyon (a sandy canyon-head fed by longshore drift) to the only other systems where numerous (>10-100) flows have been measured precisely via direct monitoring; the Squamish Delta (a sandy fjord-head delta), and the Congo Canyon (connected to the mud-dominated mouth of the Congo River). A common seasonal pattern emerges, leading to a new model for preconditioning and triggering of turbidity currents initiating through slope failure in areas of sediment accumulation, such as canyon heads or river mouths. In this model, rapid or sustained sediment supply alone can produce elevated pore pressures, which may persist, thereby predisposing slopes to fail. Once preconditioned, a range of minor external perturbations, such as moderate storm-waves, result in local pore pressure variation, and thus become effective triggers. Major external triggers are therefore not always a prerequisite for triggering of powerful turbidity currents.

direct monitoring geohazard preconditioning submarine canyon triggering turbidity current

SCI ; EI

英语

NI论文

其他

WOS:000636736200015

20211010020338

Offshore oil well production ; Pore pressure ; Rivers ; Sediment transport ; Storms ; Turbidity

Precipitation:443.3 ; Seawater, Tides and Waves:471.4 ; Soils and Soil Mechanics:483.1 ; Oil Field Production Operations:511.1 ; Light/Optics:741.1

GEOSCIENCES

2-s2.0-85101849768

Scopus

1.National Oceanography Centre,Southampton,SO14 3ZH,United Kingdom
2.School of Ocean and Earth Science,University of Southampton,Southampton,SO14 3ZH,United Kingdom
3.Pacific Coastal and Marine Science Center,U.S. Geological Survey,Santa Cruz,95060,United States
4.Departments of Geography and Earth Science,Durham University,Durham,DH1 3LE,United Kingdom
5.Monterey Bay Aquarium Research Institute,Moss Landing,95039,United States
6.Energy and Environment Institute,University of Hull,Hull,HU6 7RX,United Kingdom
7.Southern University of Science and Technology,Shenzhen,518055,China
8.National Institute of Water and Atmospheric Research,Wellington,6241,New Zealand
9.Pacific Coastal and Marine Science Center,U.S. Geological Survey,Menlo Park,94025,United States
10.

Bailey，Lewis P.,Clare，Michael A.,Rosenberger，Kurt J.,et al. Preconditioning by sediment accumulation can produce powerful turbidity currents without major external triggers[J]. EARTH AND PLANETARY SCIENCE LETTERS,2021,562.

Bailey，Lewis P..,Clare，Michael A..,Rosenberger，Kurt J..,Cartigny，Matthieu J.B..,Talling，Peter J..,...&Lundsten，Eve.(2021).Preconditioning by sediment accumulation can produce powerful turbidity currents without major external triggers.EARTH AND PLANETARY SCIENCE LETTERS,562.

Bailey，Lewis P.,et al."Preconditioning by sediment accumulation can produce powerful turbidity currents without major external triggers".EARTH AND PLANETARY SCIENCE LETTERS 562(2021).