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TitreReservoir-triggered seismicity in the Canadian Shield
AuteurLamontagne, M; Manescu, D
SourceProceedings of the 9th U.S. National and 10th Canadian Conference on Earthquake Engineering (9USN/10CCEE)/Compte Rendu de la 9ième Conférence Nationale Américaine et 10ième Conférence Canadienne de Génie Parasismique; 2010, 10 pages
Séries alt.Secteur des sciences de la Terre, Contribution externe 20100180
Réunion9th U.S. National and 10th Canadian Conference on Earthquake Engineering (9USN/10CCEE); Toronto; CA; juillet 25-29, 2010
Mediapapier; numérique
Sujetssismicité; risque sismique; milieux tectoniques; interprétations tectoniques; cadre tectonique; barrages; reservoirs; caractéristiques structurales; failles; Bouclier Canadien; tectonique
Illustrationsplots; tables
ProgrammeEastern Canada Geohazards Assessment Project, Géoscience pour la sécurité publique
Résumé(disponible en anglais seulement)
The International Commission on Large Dams (ICOLD) has recently published a Bulletin on Reservoir-Triggered Seismicity (RTS). The Bulletin, in its rough draft stage, reviews the state of knowledge on this phenomenon, and suggests a methodology to assess its likelihood in various tectonic contexts. In light of future development of hydro-electric reservoirs, we examine how this Bulletin applies to the Canadian Shield environment, i.e. a mostly seismically quiescent region that contains some active areas and five documented cases of RTS. We find that some generalizations contained in the Bulletin should be refined in light of the known RTS history in the Canadian Shield. According to the Bulletin, for example, the thrust faulting environment and the quasi absence of background seismicity make RTS unlikely in the Canadian Shield, in contradiction to the known RTS history. Another example is that the Bulletin describes reservoir-triggered earthquakes as tectonic events that occur prematurely because of the increase in pore-fluid pressure. Based on this, one could consider the regional earthquake activity representative of the potential for RTS, even though tectonic earthquakes in the Canadian Shield generally occur much deeper (5-30 km depth) than RTS (upper 1-2 km depth). We present some preliminary ideas on the assessment of RTS potential in the Canadian Shield, keeping in mind the difficulty in forecasting the impact of increased pore fluid pressures on faults that are generally unmapped, have an unknown neotectonic history and lack sufficient knowledge of their permeability. The problem of defining a representative RTS event (location, magnitude, depth) for the design of dams and appurtenant structures is also examined.