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TitrePaleoseismicity of the continental margin of eastern Canada: rare regional failures and associated turbidites in Orphan Basin
AuteurPiper, D J W; Tripsanas, E; Mosher, D C; McKillop, K
SourceExploring the deep sea and beyond: contributions to marine geology in honor of William R. Normark; par Fildani, A (éd.); Geosphere vol. 15, no. 1, 2018 p. 1-23, https://doi.org/10.1130/GES02001.1 (Accès ouvert)
Année2018
Séries alt.Secteur des sciences de la Terre, Contribution externe 20100367
ÉditeurGeological Society of America
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1130/GES02001.1
Mediaen ligne; numérique
Formatspdf (Adobe® Reader®); docx (Microsoft® Word®)
ProvinceTerre-Neuve-et-Labrador; Région extracotière de l'est
Lat/Long OENS -51.7500 -45.5000 51.0000 47.5000
Sujetsmarges continentales; talus continental; risque sismique; sismicité; secousses séismiques; risque de tremblement de terre; magnitudes des séismes; glissements de terrain; glissements de pentes; dépôts de glissement de terrain; dépôts de coulée de débris; sédiments marins; turbidites; dépôts glaciaires; carottes de sédiment marin; levés géophysiques; levés sismiques marins; levés de reflexion sismiques; profils sismiques; modèles; antécédents géologiques; antécédents tectoniques; débit de sedimentation; antecedents glaciaires; cadre tectonique; linéaments; lithostratigraphie; corrélations stratigraphiques; analyses de la stabilité des pentes; déterminations de la masse volumique en vrac; resistance au cisaillement; contrainte de cisaillement; repartition granulométrique; Zone de Charlie-Gibbs Fracture ; géologie marine; géologie des dépôts meubles/géomorphologie; géophysique; sédimentologie; tectonique; stratigraphie; géologie de l'ingénieur; Phanérozoïque; Cénozoïque; Quaternaire
Illustrationslocation maps; geoscientific sketch maps; correlation sections; seismic profiles; profiles; tables; lithologic sections; photographs; frequency distribution diagrams; stratigraphic columns; bar graphs; histograms; plots
ProgrammeLa géoscience pour les développements extracôtiers de la côte est, Géoscience en mer
Diffusé2018 12 20
Résumé(disponible en anglais seulement)
The eastern Canadian continental margin is a typical glaciated passive margin where historic earthquakes have triggered submarine landslides. This study compares seismological estimates of earthquake recurrence with the geological record over the past 85 k.y. offshore of Newfoundland to assess the reliability of the geologic record. Heinrich layers in cores provide chronology at ~3-5 k.y. resolution in high-resolution seismic-reflection profiles across headscarps and mass-transport deposits. Landslide-generated turbidites on the basin floor have distinctive petrology, sedimentology, and distribution, with ~1 k.y. chronologic resolution. Large slope failures occurred synchronously over margin lengths of 50-300 km. Since 85 ka, four failures have affected a >150-km-long sector of the slope and 18 failures were large enough to be recognized in seismic-reflection profiles and/or cores. The widespread failures were earthquake triggered; other mechanisms for triggering laterally extensive synchronous failure do not apply. A frequency-magnitude plot of length of failed slope was calibrated by the published relationship that an order-of-magnitude increase in failed slope length corresponds to two orders of magnitude of earthquake energy, together with the published estimate of Mw = 8.0 for the largest earthquake on the Canadian eastern continental margin. Mean recurrence interval of M = 7 earthquakes at any point on the margin is estimated at 25-30 k.y. from both seismological models and the sediment failure record. On such a margin with modest sedimentation rates (~0.3 m/k.y.) and low seismicity, sediment failures provide a robust estimator of past seismicity.
GEOSCAN ID287415