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TitleSubmarine landslides in Pangnirtung Fiord, Baffin Island, Nunavut
AuthorSedore, P; Normandeau, AORCID logo; Maselli, V
SourceCanada-Nunavut Geoscience Office, Summary of Activities 2021, 2022 p. 31-45 Open Access logo Open Access
LinksOnline - En ligne
Alt SeriesNatural Resources Canada, Contribution Series 20210542
PublisherCanada-Nunavut Geoscience Office
Mediapaper; on-line; digital
File formatpdf
NTS26I/03; 26I/04; 26I/05; 26I/06
AreaPangnirtung Fiord; Baffin Island
Lat/Long WENS -66.0000 -65.1667 66.4000 66.0500
Subjectsmarine geology; surficial geology/geomorphology; geophysics; geochronology; sedimentology; Science and Technology; Nature and Environment; Health and Safety; marine environments; coastal environment; fiords; landslides; debris flows; slope stability; sediment stability; geophysical surveys; acoustic surveys, marine; geophysical interpretations; geophysical logging; marine sediments; marine sediment cores; radiometric dating; radiocarbon dating; floods; sea ice; fluvial processes; morphometric studies; Natural hazards; Phanerozoic; Cenozoic; Quaternary
Illustrationslocation maps; geoscientific sketch maps; photographs; tables; plots; geophysical profiles; core logs; geophysical logs; bar graphs; lithologic logs; pie charts
ProgramPublic Safety Geoscience Baffin Bay
Released2022 03 21
AbstractAs part of the Geological Survey of Canada's continuing aim to identify the potential marine geohazards in Baffin Bay, this study sought to generate a comprehensive understanding of the distribution, timing and potential triggers of submarine landslides in Pangnirtung Fiord. The high-relief topography of Pangnirtung Fiord is comparable to fiords in Greenland and Alaska, where recent studies have investigated landslide-generated tsunamis. Since the low-lying community of Pangnirtung is situated along the coast of Pangnirtung Fiord, it is evermore critical to understand the submarine-landslide hazard of the area.
The study identified 180 near-surface submarine landslides in Pangnirtung Fiord using multibeam bathymetric and sub-bottom profiler data, along with gravity cores collected in 2019. Morphometric analysis shows that most submarine landslides are relatively small (~0.13 km2), with elongated failure zones and wide deposits dispersed along the basin floor. Radiometric dating reveals that eight of the eleven dated landslides are younger than 500 years. Landslide-surface roughness was tested as a proxy for age, but the relationship was found to be weak, thus limiting the ability to accurately date all identified landslides. Four broad categories of submarine-landslide triggers were identified and it was shown that at least 53% (96 of 180) of landslides are associated with subaerial sources and, at most, 31% (56 of 180) are shallow-water, non-subaerially influenced. This suggests that triggers of most submarine landslides within Pangnirtung Fiord include rapid flood-water input, subaerial debris flows and sea-ice loading during low tide.
Summary(Plain Language Summary, not published)
Underwater landslides are geological hazards that can cause damagedestruction to coastal communities by generating tsunamis and damaging seabed infrastructure. This project looks at underwater landslides in Pangnirtung Fiord to try and determine where and when they occurred. This will help to understand where they might occur in the future and what caused them. We mapped 90 underwater landslides using data collected in 2019. We found that most landslides probably occurred within the last 500 years and almost all underwater landslides seem to be triggered in shallow water. At least half were likely caused from processes on land like debris flows and flooding in rivers that cause a lot of water and sediment to rapidly enter the sea. Many of the other landslides may have been caused by sea-ice or icebergs hitting the seafloor or from waves at low tide. Studying these underwater landslides is important to make sure that coastal communities know the geological hazards that may impact them and their important infrastructure.

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