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TitleLarge submarine slope failures and associated Quaternary faults in Douglas Channel, British Columbia
AuthorConway, K W; Barrie, J V
SourceGeological Survey of Canada, Current Research (Online) no. 2015-9, 2015, 16 pages, (Open Access)
PublisherNatural Resources Canada
Mediaon-line; digital
File formatpdf
ProvinceBritish Columbia; Western offshore region
NTS103A/14; 103A/15; 103H/02; 103H/03; 103H/06; 103H/07; 103H/11; 103H/15
AreaDouglas Channel; Kitimat Arm; Gil Island; Princess Royal Island; Gribbell Island; Hawkesbury Island; Aristazabal Island
Lat/Long WENS-129.5000 -128.8333 53.5167 52.9000
Lat/Long WENS-128.6500 -128.6500 54.0000 53.9167
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
Illustrationslocation maps; stratigraphic columns; tables; profiles
ProgramMarine Geohazards, Public Safety Geoscience
Released2015 12 17
AbstractVery large (>60 x 106 m3) submarine slope failures occur in Douglas Channel, British Columbia. Geophysical and core data suggest that these failures were episodically active between 13 ka and 11 ka radiocarbon years BP. Radiocarbon ages indicate that regionally, near continuous sedimentation has been ongoing for approximately the last 10 000 a and that this deposition has not been interrupted by sedimentary units indicative of large-scale slope failures. The new data support an inferred bedrock sagging or sackung origin for the bedrock slides that occurred along bounding faults after support by buttressing glacial ice had been removed. Faulting, observed in seismic data affecting the Late Glacial section south of the slide area, may have contributed to slope instability along the southeastern shoreline of Douglas Channel. The observed fault may have been reactivated during glacial loading and unloading or may result from an existing regional, north-south-oriented, dextral-shear stress regime.
Summary(Plain Language Summary, not published)
Large scale infrastructure is under construction or planned for Kitimat, BC including LNG and oil export facilities. Concerns about natural hazards to these installations such as landslides, tsunamis and surface fault rupture has prompted marine geological hazards research to be undertaken by the GSC in the area of Douglas Channel and Kitimat Arm. New results, presented here, provide age constraints to previously identified very large landslides and also summarize evidence for faulting of sediments and bedrock in this area.