La séismicité provoquée au réservoir LG-2

• Published in: Canadian Journal of Earth Sciences
• Main Authors: Buchbinder, G. G. R., Anglin, F. M., McNicoll, Roger
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1981
• Subjects: General Earth and Planetary Sciences; La Grande River
• Online Access: http://dx.doi.org/10.1139/e81-064; http://www.nrcresearchpress.com/doi/pdf/10.1139/e81-064

The construction of a rock and earth-filled dam in the La Grande River valley, Quebec has created a hydroelectric reservoir with a maximum depth of 145 m and a volume of 61.7 × 10 9 m 3 . No seismicity in this Precambrian Shield region above magnitude 0.1 was observed in the reservoir zone in the 27 months preceding the filling. Microearthquakes of magnitude less than 1 started under the reservoir when a water depth of 90 m was reached after 30 days and this activity continued for about 3 months. A second series of microearthquakes began in the same active zone when the rate of filling increased twofold. The seismically active area is confined to a zone 4 km × 7 km and no deeper than 5 km. The microearthquakes are considered to be the result of minor reactivation of old faults under the reservoir in response to the increased pore pressure.