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TitreMoment magnitude - local magnitude calibration for earthquakes in western Canada
AuteurRistau, J; Rogers, G C; Cassidy, J F
SourceBulletin of the Seismological Society of America vol. 95, no. 5, 2005 p. 1994-2000, https://doi.org/10.1785/0120050028 (Accès ouvert)
Année2005
Séries alt.Secteur des sciences de la Terre, Contribution externe 2005528
ÉditeurSeismological Society of America (SSA)
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1785/0120050028
Mediapapier; en ligne; numérique
Formatspdf
ProvinceAlberta; Colombie-Britannique; Territoires du Nord-Ouest; Yukon
SNRC72E; 72L; 72M; 73D; 73E; 73L; 73M; 74D; 74E; 74L; 74M; 75D; 75E; 75L; 75M; 76D; 76E; 76L; 76M; 77B; 77C; 77F; 77G; 78B; 78C; 78F; 82; 83; 84; 85; 86; 87; 88A; 88B; 88C; 88D; 88E; 88F; 92; 93; 94; 95; 96; 97; 98A; 98B; 98C; 98D; 98E; 98F; 102; 103; 104; 105; 106; 107; 114; 115; 116; 117
Lat/Long OENS-145.0000 -110.0000 75.0000 45.0000
Sujetsséismologie; magnitudes des séismes; secousses séismiques; études séismiques; mesures des mouvements; données sismiques; tectonique de plaques; zones de subduction; croûte continentale; panneau orienté vers le bas; risque sismique; cadre tectonique; mouvements des plaques; Cordillère canadienne; géophysique; tectonique
Illustrationssketch maps; focal mechanisms; plots
ProgrammeLes risques naturels et les interventions en cas d'urgence
ProgrammeProgramme de Séismologie des Tremblements de Terre (PSTT)
Résumé(disponible en anglais seulement)
Local magnitude (ML) is the primary magnitude scale calculated for western Canada by the Geological Survey of Canada (gsc). Moment magnitude (Mw), derived from moment tensor analysis, provides a more robust estimate of the magnitude of earthquakes but is more demanding to calculate. Moment tensor analysis of regional seismic data for earthquakes with magnitudes larger than 3.5 in western Canada is now possible owing to the installation of more than 40 three-component broadband stations in western Canada, the Pacific Northwest of the United States, and southeast Alaska. More than 100 regional moment tensor solutions have been calculated in the Canadian Cordillera and Vancouver Island/Puget Sound region for 1996-2004 at the gsc. These solutions, along with 45 prior solutions, allow the calibration of Mw-ML throughout much of western Canada. Continental crust events in the Canadian Cordillera and Vancouver Island/Puget Sound region are found to have Mw = ML for earthquakes with ML ? 3.6. In contrast, earthquakes located within the subducting slab in the Vancouver Island/Puget Sound region, where there are complex source-receiver travel paths, have Mw systematically larger than ML by nearly 0.6 magnitude units. The calibrations of Mw with ML are an important result that will allow the western Canadian earthquake database to be used more effectively for tectonic studies and seismic hazard analysis.
GEOSCAN ID221505