GEOSCAN, résultats de la recherche


TitreRepetitive seabed mapping to constrain iceberg scour frequency estimates, offshore Labrador
AuteurSonnichsen, G V; Breton, C; Carr, E; Campbell, P; King, T
SourceProceedings of the 20th International Conference of Port and Ocean Engineering under Arctic Conditions (POAC); Poac09-80, 2009, 10 pages
Séries alt.Secteur des sciences de la Terre, Contribution externe 20100115
Réunion20th International Conference of Port and Ocean Engineering under Arctic Conditions (POAC); Lulea; SE; juin 9-12, 2009
Documentpublication en série
ProvinceRégion extracotière de l'est
SNRC13O; 14C; 14F
Lat/Long OENS -62.0000 -58.0000 58.0000 55.0000
Sujetsgougeage de la glace; icebergs; pipelines; érosions par la glace; affouillement; sonar latéral; levés géophysiques; géologie marine; géophysique
Illustrationslocation maps
ProgrammeAléas géologiques et contraintes à la mise en valeur des ressources extracôtières, Géosciences à l'appui de la gestion des océans
Résumé(disponible en anglais seulement)
Subsea facilities and pipelines offshore Labrador will require protection from damage from keel-dragging icebergs, however, protection requirements remain uncertain, in large part because the impact frequency is poorly constrained. Here we present new Labrador shelf iceberg scour frequency estimates based on repetitive seabed mapping surveys over 18 to 27 years. Two sidescan sonar mosaics were compared over 25 years on eastern Saglek Bank between 156 and 192 metres water depth (mwd). Four new furrows were recognized, resulting in an average scour frequency of 3.8 x 10-3 km-2 yr-1. On western Saglek Bank between 140 and 175 mwd, 2 new furrows were identified comparing 1981 sidescan sonar to 2006 multibeam sonar data. The calculated scour rate for western Saglek Bank is 2.2 x 10-3 km-2 yr-1. New ice scour events occurred most frequently at Caroline, the most northern site and also the shallowest in 115 to 121 metres water depth: 12 new furrows and 3 pits occurred between 1979 and 2006: the combined impact rate for both furrows and pits is 4.4 x 10-2 km-2 yr-1. The Saglek Bank repetitive mapping sites provide a valuable upper constraint on scour frequency estimates for Makkovik Bank, the site of proposed natural gas development, approximately 500 km to the south.