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TitleNew insight into marine and terrestrial geohazards in north coastal British Columbia
AuthorHuntley, D; Bobrowsky, P; Sawai, Y; Tanigawa, K; Goff, J; Chague-Goff, C; Gadd, P; MacLeod, R; Enkin, R; Conway, K; Barrie, V; Neelands, P; Middleton, G; Lintern, G
Source1st International Symposium on Marine Engineering Geology, program with abstracts; 2016, 1 pages
Image
Year2016
Alt SeriesEarth Sciences Sector, Contribution Series 20160235
PublisherInternational Union of Geological Sciences
PublisherInternational Association of Enginnering Geology
Meeting1st International Symposium on Marine Engineering Geology; Qingdao; CN; October 21-24, 2016
Documentbook
Lang.English
Mediapaper
File formatpdf
ProvinceBritish Columbia; Western offshore region
AreaMoon Bay; Kitimat
Subjectsengineering geology; Health and Safety; soils science; coastal management; coastal environment; coastal erosion; landslides; slumps; tsunami; Pacific Northwest; slope monitoring; geoscience outreach; change detection
Illustrationsimages; location maps; logs; 3-D models
ProgramMarine Geohazards Mapping & Monitoring (MGMM), Submarine Landslides
AbstractFor Canada and the global energy market, future economic sustainability will require safe and secure transportation corridors connecting natural resources in northeastern British Columbia, Alberta and Saskatchewan with the deep-water ports on the Pacific Northwest coast. From our investigations in north coastal British Columbia, we now have field evidence of inundation of low-lying terrain by far-field seismogenic tsunamis, and by local displacement waves generated by large volume landslides, rock fall and submarine slumps. The recurrence of such geohazards will challenge development of new pipeline and shipping infrastructure, and threaten the safety of isolated coastal communities in the region. The focus of our exploratory research has been to identify sedimentological, geochemical and biological signals that will distinguish tsunamis generated by plate boundary earthquakes and landslide-generated displacement waves; extend and improve the paleotsunami records of the Pacific basin; and by providing physical evidence to help constrain modelling of future tsunamigenic events. We have focused our investigation on salt marsh peat deposits and forest soils developed on the outboard archipelago on the east of Hecate Strait, around Prince Rupert on the coastal fringes of Chatham Sound, and in the narrow fjord inlets, estuaries, bays and coves of the Douglas Channel near Kitimat. These coastal landforms have amplified incoming far-field seismogenic tsunamis and local displacement waves generated by large volume landslides, rock fall and submarine slumps. Pacific Basin sourced tsunamis appear to expend much of their energy in the outer coastal channels, reefs and islands (e.g., Price, Aristazabal, Dewdney and Gil islands), and may not reach a far as Kitimat at the head of Douglas Channel. Evidence for a 1975 tsunami generated by the anthropogenically-triggered Moon Bay marine slump (and possibly earlier events) is preserved in Cumulic soil profiles beyond the storm berms in Minette Bay and Clio Bay near Kitimat. This suggests only local landslides above a certain threshold volume and energy will produce tsunamis of the magnitude of the 1975 event or greater. Of particular interest in this context are large volume submarine slide scars in bedrock and glacial sediments observed on the southwest flank of Hawkesbury Island, near the community of Hartley Bay. Landward of these features, deep-seated sackung-like bedrock lineaments are observed that have the potential to generate locally destructive earthquakes and tsunamis during slope failure. A multi-year change-detection analysis incorporating InSAR monitoring techniques and photogrammetric reconstruction of the terrestrial slopes using commercial Structure from Motion software will identify areas of past and current instability. In conclusion, new insight into geohazards in north coastal British Columbia offered by our work is helping to reduce the development risks to governments, resource industries, the environment and communities in the region.
Summary(Plain Language Summary, not published)
For Canada and the global energy market, future economic sustainability will require safe and secure transportation corridors connecting natural resources in northeastern British Columbia, Alberta and Saskatchewan with the deep-water ports on the Pacific Northwest coast. From our investigations in north coastal British Columbia, we now have field evidence of inundation of low-lying terrain by far-field tsunamis, and by local displacement waves generated by large volume landslides, rock fall and submarine slumps.
GEOSCAN ID299368