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Are submarine landslides an underestimated hazard on the western North Atlantic passive margin?

Alexandre Normandeau, D. Calvin Campbell, David J. W. Piper and Kimberley A. Jenner
Are submarine landslides an underestimated hazard on the western North Atlantic passive margin?
Geology (Boulder) (July 2019) 47 (9): 848-852

Abstract

The western North Atlantic passive margin is considered relatively stable, with few slope instabilities recognized during the Holocene. However, new multibeam bathymetry mapping and sediment core acquisition off eastern Canada indicate that previously unidentified, large, submarine landslide events occurred during the Late Holocene, between 4 and 1.5 ka. The recognition of these new gravitational events, in addition to the well-known C.E. 1929 Grand Banks earthquake-induced landslide, indicates that approximately one large landslide event per 1000 years has occurred offshore eastern Canada within the past 4000 years, a much shorter recurrence interval than hitherto reported. This Late Holocene recurrence rate is also similar to active margins around the world and is likely due to the under-consolidation and resultant instability of Scotian Slope sediments attributable to high glacial sedimentation rates. The discovery of these new Late Holocene landslides was made possible through detailed examination of cores recovered from the lower slope. These results demonstrate that submarine landslide hazard has been underestimated on the western North Atlantic margin-home to significant submarine infrastructure and proximal to a large coastal population.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 47
Serial Issue: 9
Title: Are submarine landslides an underestimated hazard on the western North Atlantic passive margin?
Affiliation: Canadian Geological Survey, Dartmouth, NS, Canada
Pages: 848-852
Published: 20190710
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 24
Accession Number: 2019-065638
Categories: Environmental geologyQuaternary geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sect., sketch map
N41°00'00" - N42°30'00", W57°00'00" - W55°00'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201934
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