Subaqueous Mass Movements and their Consequences: Advances in Process Understanding, Monitoring and Hazard Assessments
This volume focuses on underwater or subaqueous landslides with the overarching goal of understanding how they affect society and the environment. The new research presented here is the result of significant advances made over recent years in directly monitoring submarine landslides, in standardizing global datasets for quantitative analysis, constructing a global database and from leading international research projects. Subaqueous Mass Movements demonstrates the breadth of investigation taking place into subaqueous landslides and shows that, while events like the recent ones in the Indonesian archipelago can be devastating, they are at the smaller end of what the Earth has experienced in the past. Understanding the spectrum of subaqueous landslide processes, and therefore the potential societal impact, requires research across all spatial and temporal scales. This volume delivers a compilation of state-of-the-art papers covering topics from regional landslide databases to advanced techniques for in situ measurements, to numerical modelling of processes and hazards.
Submarine canyons, slope failures and mass transport processes in southern Cascadia
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Published:June 11, 2020
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CiteCitation
Jenna C. Hill, Janet T. Watt, Daniel S. Brothers, Jared W. Kluesner, 2020. "Submarine canyons, slope failures and mass transport processes in southern Cascadia", Subaqueous Mass Movements and their Consequences: Advances in Process Understanding, Monitoring and Hazard Assessments, A. Georgiopoulou, L. A. Amy, S. Benetti, J. D. Chaytor, M. A. Clare, D. Gamboa, P. D. W. Haughton, J. Moernaut, J. J. Mountjoy
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Abstract
Marine turbidite records have been used to infer palaeoseismicity and estimate recurrence intervals for large (>Mw7) earthquakes along the Cascadia Subduction Zone. Conventional models propose that upper slope failures are funneled into submarine canyons and develop into turbidity flows that are routed down-canyon to deep-water channel and fan systems. However, the sources and pathways of these turbidity flows are poorly constrained, leading to uncertainties in the connections between ground shaking, slope failure and deep-water turbidites. We examine the spatial distribution of submarine landslides along the southern Cascadia margin to identify source regions for slope failures that may have developed into turbidity flows. Using multibeam bathymetry, sparker multichannel seismic and chirp sub-bottom data, we observe relatively few canyon head slope failures and limited evidence of large landslides on the upper and middle slope. Most of the submarine canyons are draped with sediment infill in the upper reaches and do not appear to be active sediment conduits during the recent sea-level highstand. In contrast, there is evidence of extensive mass wasting of the lower slope and non-channelized downslope flows. Contrary to previous studies, we propose that failures along the lower slope are the primary sources for deep-sea seismoturbidites in southern Cascadia.
- bathymetry
- bottom features
- Cascadia subduction zone
- currents
- deep-sea environment
- earthquakes
- East Pacific
- Eel River
- failures
- geophysical methods
- geophysical profiles
- geophysical surveys
- marine environment
- mass movements
- multibeam methods
- multichannel methods
- North Pacific
- Northeast Pacific
- ocean floors
- Pacific Ocean
- paleoseismicity
- recurrence interval
- sea-level changes
- sediment transport
- sedimentary structures
- seismic methods
- seismic profiles
- seismites
- slope stability
- slopes
- slumping
- spatial distribution
- stratigraphy
- submarine canyons
- surveys
- tectonics
- transport
- turbidite
- turbidity currents
- Smith Canyon
- Mendocino Canyon
- Trinidad Canyon
- Klamath Canyon
- Eel Plateau
- Sixes Canyon