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TitleA preliminary assessment of the occurrence of submarine slope failures in coastal British Columbia by analysis of swath multibeam bathymetric data collected 2001-2011
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AuthorConway, K W; Kung, R B; Barrie, J V; Hill, P R; Lintern, D G
SourceGeological Survey of Canada, Open File 7348, 2013, 38 pages, https://doi.org/10.4095/292370
Year2013
PublisherNatural Resources Canada
Documentopen file
Lang.English
Mediaon-line; digital
File formatreadme
File formatpdf; rtf; mxd; pmf; xml
ProvinceBritish Columbia; Western offshore region
NTS92B; 92F; 92G/03; 92G/04; 92G/05; 92G/06; 92F/08; 92F/09; 92F/10; 92F/15; 92F/16; 92K; 92L; 103G; 103J
AreaStrait of Georgia; Johnstone Strait; Queen Charlotte Strait
Lat/Long WENS-131.0000 -122.0000 54.5000 48.2500
Subjectsgeophysics; marine geology; bathymetry; seafloor topography; seabottom topography; submarine features; submarine transport; slope failures; slope stability; slope deposits; Holocene; tsunami; structural features; faults; marine deposits; marine sediments; marine environments
Illustrationstables
ProgramMarine Geohazards, Public Safety Geoscience
Released2013 03 29
AbstractAn inventory of submarine slope instability features has been compiled for coastal areas of British Columbia based on morphologic analysis of regional multibeam bathymetric data. The slope instability features are classified as submarine slides, debris flows, rock avalanches and associated features including fan deltas, sediment cones and channel complexes. In addition, the study provides an initial assessment of the size and distribution of these geohazards, with a particular focus on identifying large features that are the result of a single failure event because these would have the greatest potential to generate a damaging tsunami. Submarine landslide deposits have been identified in all fjords and inlets examined including Bute, Knight, Toba and Jervis Inlets and Howe Sound. Douglas Channel, Kitimat Arm and Alberni Inlets also have significant landslide derived sediment bodies on the margin and floors of these inlets. In the Strait of Georgia extensive failures have been identified along the Fraser River delta and on slopes where sediment accretion has occurred in the Holocene, including spits and other coastal landforms. The locus of nearly all submarine slope failures in Juan de Fuca Strait has been along the edge of a terrace landform associated with sea level lowstand. Whereas the age of some features can be tentatively inferred by association with modern or postglacial morphology, the exact age of the instability features documented in this study cannot be determined from this morphologic analysis alone. The accompanying ArcGIS document allows each instability feature to be located and queried for information such as morphologic classification, surface area, possible age, and other details.
Summary(Plain Language Summary, not published)
The Open File provides a summary of submarine landslide deposits in coastal BC that are of concern because of the possibility of damage to coastal construction or hazard to people from future landslides. The data studied for this report were collected between 2001 and 2011. The summary provides the locations and size of the landlsides seen in sophisticated echo sounder data (swath multibeam sonar) and suggests the ways in which the slides occurred during land sliding. Areas that need to be studied in the future area also described.
GEOSCAN ID292370